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Title:
TISSUE PAPER PRODUCT COMPRISING A QUATERNARY AMMONIUM COMPOUND, A POLYSILOXANE COMPOUND AND BINDER MATERIALS
Document Type and Number:
WIPO Patent Application WO/1996/019616
Kind Code:
A1
Abstract:
Tissue paper products comprising a two-component chemical softener composition and binder materials, either permanent or temporary wet strength binders, and/or dry strength binders are disclosed. The two-component chemical softening composition comprises a quaternary ammonium compound and a polysiloxane compound. Preferred quaternary ammonium compounds include dialkyl dimethyl ammonium salts such as di(hydrogenated)tallow dimethyl ammonium chloride and/or di(hydrogenated)tallow dimethyl ammonium methyl sulfate. Preferred polysiloxanes include amino-functional polydimethyl polysiloxanes wherein less than about 10 mole percent of the side chains on the polymer contain an amino-functional group.

Inventors:
Ampulski
Robert
Stanley, Monteith
Joel
Kent, Ostendorf
Ward
William, Phan
Dean
Van, Trokhan
Paul
Dennis
Application Number:
PCT/US1995/015420
Publication Date:
June 27, 1996
Filing Date:
November 28, 1995
Export Citation:
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Assignee:
THE PROCTER & GAMBLE COMPANY.
International Classes:
A47K7/00; D21H17/07; D21H17/28; D21H17/55; D21H17/59; D21H21/20; D21H21/22; D21H27/30; D21H27/38; (IPC1-7): D21H17/59; D21H17/07; D21H21/22; D21H27/38
Domestic Patent References:
WO1993002252A1
Foreign References:
EP0607796A1
US5246546A
US5312522A
EP0347153A2
Download PDF:
Claims:
What is claimed is:
1. A tissue paper product characterized in that it comprises: a) paper making fibers; b) from 0.01 % to 3.0% of a quaternarγ ammonium compound; c) from 0.01 % to 3.0% of a polγsiloxane compound; and d) from 0.01 % to 3.0% of binder materials, either wet strength binders and/or drγ strength binders, preferablγ both a wet strength binder and a drγ strength binder.
2. The tissue paper product of Claim 1 comprising at least two plies, wherein each of said plies comprises at least two superposed laγers, an inner laγer and an outer laγer contiguous with said inner laγer, wherein said tissue paper product preferablγ comprises two plies in juxtaposed relation, said plies being oriented in said tissue so that said outer laγer of each plγ forms one exposed surface of said tissue paper product and each of said inner laγers of said plies are disposed toward the interior of said tissue paper product.
3. The multilaγered tissue paper product of Claim 2 wherein the majoritγ of the quaternarγ ammonium compound and the majoritγ of the polγsiloxane compound is contained in at least one of said outer laγers, preferablγ in both of said outer laγers.
4. The multilaγered tissue paper product of Claim 2 or 3 wherein the majoritγ of the binders is contained in at least one of said inner laγers.
5. The multilaγered tissue paper product of Claim 2 or 3 wherein the majoritγ of said binders is contained in said outer laγers.
6. The multilaγered tissue paper product of anγ of Claims 2 5 wherein each of two said inner iaγers comprise relativelγ long paper making fibers having an average length of at least 2.0 mm and wherein each of two said outer laγers comprises relativelγ short paper making fibers having an average length between 0.2 mm and 1.5 mm.
7. The multilaγered tissue paper product of anγ of Claims 2 6 wherein said inner laγers comprise softwood fibers, preferablγ northern softwood Kraft fibers, and said outer laγers comprise hardwood fibers, preferablγ eucalγptus fibers.
8. The tissue paper product of anγ of Claims 17 wherein said wet strength binders are permanent wet strength binders selected from polγamideepichlorohγdrin resins, polγacrγlamide resins, and mixtures thereof, preferablγ polγamideepichlorohγdrin resins, or temporarγ wet strength binders selected from cationic dialdehγde starchbased resins, dialdehγde starch resins and mixtures thereof, preferablγ cationic dialdehγde starchbased resins; and wherein said drγ strength binder is selected from carboxγmethγl cellulose resins, starch based resins, polγacrγlamide resins, polγvinγl alcohol resins and mixtures thereof, preferablγ carboxγmethγl cellulose resins.
9. The tissue paper product of anγ of Claims 18 wherein the quaternarγ ammonium compound has the formula : (Rl >4m N + [R2lm X" wherein m is 1 to 3; each R*| is a CjCs alkγl group, hγdroxγalkγl group, hγdrocarbγi or substituted hγdrocarbγl group, alkoxγlated group, benzγl group, or mixtures thereof, preferablγ C* C3 alkγl; each R2 is a C9C41 alkγl group, hγdroxγalkγl group, hγdrocarbγl or substituted hγdrocarbγl group, alkoxγlated group, benzγl group, or mixtures thereof, preferablγ Cj β C*|g alkγl; and X' is anγ softenercompatible anion, preferablγ chloride or methγl sulfate, wherein the quaternarγ ammonium compound is preferablγ di(hγdrogenated)tallow dimethγl ammonium chloride or di(hγdrogenated)tallow dimethγl ammonium methγl sulfate.
10. The tissue paper product of anγ of Claims 1 9 wherein said polγsiloxane is polγdimethγlsiloxane having a hγdrogen bonding functional group selected from amino, carboxγl, hγdroxγl, ether, polγether, aldehγde, ketone, amide, ester, and thiol groups, preferablγ an aminofunctional group, said hγdrogen bonding functional group being present in a molar percentage of substitution of 20% or less, preferablγ 10% or less, most preferablγ from 1.0% to 5%, said polγsiloxane having a viscositγ of from 25 centistokes to 20,000,000 centistokes.
Description:
TISSUE PAPER PRODUCT COMPRISING A QUATERNARY AMMONIUM COMPOUND, A POLYSILOXANE COMPOUND AND BINDER MATERIALS

FIELD OF THE INVENTION

This invention relates to tissue paper products. More particularly, it relates to tissue paper products comprising a two component chemical softener composition and binder materials, either permanent or temporary wet strength binders, and/or dry strength binders. The treated tissue webs can be used to make soft, absorbent and lint resistant paper products such as facial tissue paper products or toilet tissue paper products.

BACKGROUND OF THE INVENTION

Paper webs or sheets, sometimes called tissue or paper tissue webs or sheets, find extensive use in modern society. Such items as facial and toilet tissues are staple items of commerce. It has long been recognized that four important physical attributes of these products are their strength, their softness, their absorbencγ, including their absorbency for aqueous systems; and their lint resistance, including their lint resistance when wet. Research and development efforts have been directed to the improvement of each of these attributes without seriously affecting the others as well as to the improvement of two or three attributes simultaneously.

Strength is the ability of the product, and its constituent webs, to maintain physical integrity and to resist tearing, bursting, and shredding under use conditions, particularly when wet.

Softness is the tactile sensation perceived by the consumer as he/she holds a particular product, rubs it across his/her skin, or crumples it within his/her hand. This tactile sensation is provided by a combination of several physical properties. Important physical properties related to softness are generally considered by those skilled in the art to be the stiffness, the surface smoothness and lubricity of the paper web from which the product is made. Stiffness, in turn, is usually considered to be directly dependent on the dry tensile strength of the web and the stiffness of the fibers which make up the web.

Absorbency is the measure of the ability of a product, and its constituent webs, to absorb quantities of liquid, particularly aqueous solutions or dispersions. Overall absorbency as perceived by the consumer is generally considered to be a combination of the total quantity of liquid a given mass of tissue paper will absorb at saturation as well as the rate at which the mass absorbs the liquid.

Lint resistance is the ability of the fibrous product, and its constituent webs, to bind together under use conditions, including when wet. In other words, the higher the lint resistance is, the lower the propensity of the web to lint will be.

The use of wet strength resins to enhance the strength of a paper web is widely known. For example, Westfelt described a number of such materials and discussed their chemistry in Cellulose Chemistry and Technology, Volume 13, at pages 813-825 (1979). Freimark et al. in U.S. Pat. No. 3,755,220 issued August 28, 1973 mention that certain chemical additives known as debonding agents interfere with the natural fiber-to-fiber bonding that occurs during sheet formation in paper making processes. This reduction in bonding leads to a softer, or less harsh, sheet of paper. Freimark et al. go on to teach the use of wet strength resins in conjunction with the use of debonding agents to off-set the undesirable effects of the debonding agents. These debonding agents do reduce both dry tensile strength and wet tensile strength.

Shaw, in U.S. Pat. No. 3,821 ,068, issued June 28, 1974, also teaches that chemical debonders can be used to reduce the stiffness, and thus enhance the softness, of a tissue paper web.

Chemical debonding agents have been disclosed in various references such as U.S. Pat. No. 3,554,862, issued to Hervey et al. on January 12, 1971. These materials include quaternary ammonium salts such as cocotrimethylammonium chloride, oleyltrimethylammonium chloride, di(hydrogenated)tallow dimethyl ammonium chloride and stearγltrimethyl ammonium chloride.

Emanuelsson et al., in U.S. Pat. No. 4, 144,122, issued March 13, 1979, and Hellsten et al., in U.S. patent 4,476,323, issued October 9, 1984, teach the use of complex quaternary ammonium compounds such as bis(alkoxy(2-hydroxγ)propylene) quaternary ammonium chlorides to soften webs. These authors also attempt to overcome any decrease in absorbency caused by the debonders through the use of nonionic surfactants such as ethylene oxide and propylene oxide adducts of fatty alcohols.

Armak Company, of Chicago, Illinois, in their bulletin 76-17 (1977) disclose the use of dimethyl di(hγdrogenated)tallow ammonium chloride in combination with fatty acid esters of polyoxyethylene glycols to impart both softness and absorbency to tissue paper webs.

One exemplary result of research directed toward improved paper webs is described in U.S. Pat. No. 3,301 ,746, issued to Sanford and Sisson on January 31 , 1967. Despite the high quality of paper webs made by the process described in this patent, and despite the commercial success of products formed from these webs, research efforts directed to finding improved products have continued.

For example, Becker et al. in U.S. Pat. No. 4,158,594, issued January 19, 1979, describe a method they contend will form a strong, soft, fibrous sheet. More specifically, they teach that the strength of a tissue paper web (which may have been softened by the addition of chemical debonding agents) can be enhanced by adhering, during processing, one surface of the web to a creping surface in a fine patterned arrangement by a bonding material (such as an acrylic latex rubber emulsion, a water soluble resin, or an elastomeric bonding material) which has been adhered to one surface of the web and to the creping surface in the fine patterned arrangement, and creping the web from the creping surface to form a sheet material.

The two component chemical softening compositions of the present invention comprise a quaternary ammonium compound and a polγsiloxane compound. Unexpectedly, it has been found that the two component chemical softening composition improves the softness of the treated tissue paper compared to the softness benefits obtained from the use of either component individually. In addition, the lint / softness relationship of the treated tissue is also greatly improved.

Unfortunately the use of chemical softening compositions comprising a quaternary ammonium compound and a polysiloxane compound can decrease the strength and the lint resistance of the treated paper webs. Applicants have discovered that both strength and lint resistance can be improved through the use of suitable binder materials such as wet and dry strength resins and retention aid resins known in the paper making art.

The present invention is applicable to tissue paper in general, but particularity applicable to multi-ply, multi-layered tissue paper products such as those described in U.S. Patent 3,994,771 , issued to Morgan Jr. et al. on November 30, 1976, and in U.S. Patent 4,300,981 , Carstens, issued November 17, 1981 , both of which are incorporated herein by reference.

The tissue paper products of the present invention contain an effective amount of binder materials, either permanent or temporary wet strength binders, and/or dry strength binders to control li ing and/or to offset the loss in tensile strength, if any, resulting from the use of the two component chemical softening compositions.

It is an object of this invention to provide soft, absorbent and lint resistant tissue paper products.

It is also a further object of this invention to provide a process for making soft, absorbent, lint resistant tissue paper products.

These and other objects are obtained using the present invention, as will become readily apparent from a reading of the following disclosure.

SUMMARY OF THE INVENTION

The present invention provides soft, absorbent, lint resistant tissue paper products comprising :

a) paper making fibers;

b) from about 0.01 % to about 3.0% of a quaternary ammonium compound;

c) from about 0.01 % to about 3.0% of a polysiloxane compound; and

d) from about 0.01 % to about 3.0% of binder materials, either wet strength binders and/or dry strength binders.

Examples of quaternary ammonium compounds suitable for use in the present invention include the well-known dialkyldimethylammonium salts such as DiTallow DiMethyl Ammonium Chloride (DTDMAC), DiTallow DiMethyl Ammonium Methyl Sulfate (DTDMAMS), Di(Hydrogenated)Tallow DiMethyl Ammonium Methyl Sulfate (DHTDMAMS), Di(Hydrogenated)Tallow DiMethyl Ammonium Chloride (DHTDMAC).

Examples of polysiloxane materials for use in the present invention include an amino-functional polydimethylpolysiloxane wherein less than about 10 mole percent of the side chains on the polymer contain an amino- functional group. Because molecular weights of polysiloxanes can be difficult to ascertain, the viscosity of a polysiloxane is used herein as an objectively ascertainable indicia of molecular weight. Accordingly, for example, about 2 mole percent substitution has been found to be very effective for polysiloxanes having a viscosity of about one-hundred-twenty- five (125) centistokes; and viscosities of about five-million (5,000,000) centistokes or more are effective with or without substitution. In addition to such substitution with amino-functional groups, effective substitution may be made with carboxyl, hydroxyl, ether, polyether, aldehyde, ketone, amide, ester, and thiol groups. Of these effective substituent groups, the

family of groups comprising amino, carboxyl, and hydroxyl groups are more preferred than the others; and amino-functional groups are most preferred.

Exemplary commercially available polysiloxanes include DOW 8075 and DOW 200 which are available from Dow Corning; and Silwet 720 and Ucarsil EPS which are available from Union Carbide.

The term binder refers to the various wet and dry strength additives, and retention aids known in the art. These materials produce the functional strength required by the product, improve the lint resistance of the tissue paper webs of the present invention as well as counteracting any decrease in tensile strength caused by chemical softening compositions. Examples of suitable binder materials include: permanent wet strength binders (i.e. Kymene * 557H marketed by Hercules Incorporated of Wilmington, DE), temporary wet strength resins: cationic dialdehyde starch-based resin (such as Caldas produced by Japan Carlet or Cobond 1000 produced by National Starch) and dry strength binders (i.e. carboxymethyl cellulose marketed by Hercules Incorporated of Wilmington, DE, and Redibύnd 5320 marketed by National Starch and Chemical corporation of Bridgewater, NJ).

The tissue paper products of the present invention preferably comprise from about 0.01 % to about 3.0% of binder materials, either permanent or temporary wet strength binders, and/or from about 0.01 % to about 3.0% of a dry strength binder.

Without being bound by theory, it is believed that the quaternary ammonium softener compounds are effective debonding agents that act to debond the fiber-to-fiber hydrogen bonds in the tissue sheet. The combination of debonding hydrogen bonds with the polysiloxane softener, along with the introduction of chemical bonds with the wet and dry strength binders decreases the overall bond density of the tissue sheet without compromising strength and lint resistance. A reduced bond density will create a more flexible sheet overall, with improved surface softness. Important measures of these physical property changes are the FFE-lndex (Carstens) and the bulk flexibility, slip-and-stick coefficient of friction, and physiological surface smoothness as described in Ampuiski at al., 1991 International Paper Physics Conference Proceedings, book 1 , page 19 - 30, incorporated herein by reference.

Briefly, the process for making the tissue paper products of the present invention comprises the steps of formation of a single-layered or multi-layered paper making furnish from the aforementioned components except for the polysiloxane compound, deposition of the paper making furnish onto a foraminous surface such as a Fourdrinier wire, and removal of the water from the deposited furnish. The polysiloxane compound is preferably added to at least one surface of the dried tissue paper web. The resulting single-layered or multi-layered tissue webs can be combined with one or more other tissue webs to form a multi-ply tissue.

All percentages, ratios and proportions herein are by weight unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWINGS

While the Specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed the invention is better understood from the following description taken in conjunction with the associated drawings, in which :

Figure 1 is a schematic cross-sectional view of a two-ply, two-layer tissue paper in accordance with the present invention.

Figure 2 is a schematic cross-sectional view of a three-ply, single- layer tissue paper in accordance with the present invention.

Figure 3 is a a schematic cross-sectional view of a single-ply, three- layer tissue paper in accordance with the present invention.

Figure 4 is a schematic representation of a papermaking machine useful for producing a soft tissue paper in accordance with the present invention.

The present invention is described in more detail below.

DETAILED DESCRIPTION OF THE INVENTION

While this specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as the invention, it is believed that the invention can be better understood from a reading of the following detailed description and of the appended examples.

As used herein, the term "lint resistance" is the ability of the fibrous product, and its constituent webs, to bind together under use conditions, including when wet. In other words, the higher the lint resistance is, the lower the propensity of the web to lint will be.

Two Component Chemical Softener Compositions

The present invention contains as an essential component a chemical softening composition comprising a quaternary ammonium compound and a polysiloxane compound. The ratio of the quaternary ammonium compound to the polysiloxane compound ranges from about 3.0 : 0.01 to 0.01 : 3.0; preferably, the weight ratio of the quaternary ammonium compound to the polysiloxane compound is about 1.0 : 0.3 to 0.3 : 1.0; more preferably, the weight ratio of the quaternary ammonium compound to the polysiloxane compound is about 1.0 : 0.7 to 0.7 : 1.0 . Each of these types of compounds will be described in detail below.

A. Quaternary Ammonium Compound

The chemical softening composition contains as As used herein, the term "binder" refers to the various wet and dry strength resins and retention aid resins known in the paper making art.

As used herein, the term "water soluble" refers to materials that are soluble in water to at least 3% at 25 °C.

As used herein, the terms "tissue paper web, paper web, web, paper sheet and paper product" all refer to sheets of paper made by a process comprising the steps of forming an aqueous paper making furnish, depositing this furnish on a foraminous surface, such as a Fourdrinier wire, and removing the water from the furnish as by gravity or vacuum-assisted drainage, with or without pressing, and by evaporation.

As used herein, an "aqueous paper making furnish" is an aqueous slurry of paper making fibers and the chemicals described hereinafter.

As used herein, the term "multi-layered tissue paper web, multi- layered paper web, multi-layered web, multi-layered paper sheet and multi- layered paper product" all refer to sheets of paper prepared from two or more layers of aqueous paper making furnish which are preferably comprised of different fiber types, the fibers typically being relatively long softwood and relatively short hardwood fibers as used in tissue paper making. The layers are preferably formed from the deposition of separate streams of dilute fiber slurries, upon one or more endless foraminous screens. If the individual layers are initially formed on separate wires, the layers are subsequently combined (while wet) to form a layered composite web.

As used herein the term "multi-ply tissue paper product" refers to a tissue paper consisting of at least two plies. Each individual ply in turn can consist of single-layered or multi-layered tissue paper webs. The multi-ply structures are formed by bonding together two or more tissue webs such as by glueing or embossing.

It is anticipated that wood pulp in ail its varieties will normally comprise the paper making fibers used in this invention. However, other cellulose fibrous pulps, such as cotton liners, bagasse, rayon, etc., can be used and none are disclaimed. Wood pulps useful herein include chemical pulps such as Kraft, sulfite and sulfate pulps as well as mechanical pulps including for example, ground wood, thermomechanical pulps and Chemi- ThermoMechanical Pulp (CTMP). Pulps derived from both deciduous and coniferous trees can be used.

Synthetic fibers such as rayon, polyethylene and polypropylene fibers, may also be utilized in combination with the above-identified natural celluose fibers. One exemplary polyethylene fiber which may be utilized is Pulpex ® , available from Hercules, Inc. (Wilmington, Del.).

Both hardwood pulps and softwood pulps as well as blends of the two may be employed. The terms hardwood pulps as used herein refers to fibrous pulp derived from the woody substance of deciduous trees (angiosperms): wherein softwood pulps are fibrous pulps derived from the

woody substance of coniferous trees (gymnosperms). Hardwood pulps such as eucalyptus are particularity suitable for the outer layers of the multi- layered tissue webs described hereinafter, whereas northern softwood Kraft pulps are preferrred for the inner layer(s) or ply(s). Also applicable to the present invention are low cost fibers derived from recycled paper, which may contain any or all of the above categories as well as other non-fibrous materials such as fillers and adhesives used to facilitate the original paper making. an essential component from about 0.01 % to about 3.00% by weight, preferably from about 0.01 % to about 1.00% by weight of a quaternary ammonium compound having the formula:

(Rl ) -m - N + - [R2l m X "

wherein m is 1 to 3; each R-| is a C-j-Cg alkyl group, hydroxyalkγl group, hydrocarbyl or substituted hydrocarbyl group, alkoxγlated group, benzyl group, or mixtures thereof; each R2 is a C9-C41 alkyl group, hydroxyalkγl group, hydrocarbyl or substituted hydrocarbyl group, alkoxγlated group, benzyl group, or mixtures thereof; and

X " is any softener-compatible anion.

As discussed in Swern, Ed. in Bailey's Industrial Oil and Fat Products, Third Edition, John Wiley and Sons (New York 1964), tallow is a naturally occurring material having a variable composition. Table 6.13 in the above- identified reference edited by Swern indicates that typically 78% or more of the fattγ acids of tallow contain 16 or 18 carbon atoms. Typically, half of the fatty acids present in tallow are unsaturated, primarily in the form of oleic acid. Synthetic as well as natural "tallows" fail within the scope of the present invention. Preferably, each R2 is C16-C18 alkyl, most preferably each R2 is straight-chain C18 alkyl. Preferablγ, each R1 is methγl and X' is chloride or methγl sulfate. Optionally, the R2 substituent can be derived from vegetable oil sources.

Examples of quaternarγ ammonium compounds suitable for use in the present invention include the well-known dialkγldimethγlammonium salts such as ditallow dimethγl ammonium chloride, ditallow dimethγlammonium methγl sulfate, di(hγdrogenated)tallow dimethγl ammonium chloride; with di(hγdrogenated)taliow dimethyl ammonium methyl sulfate being preferred. This particular material is available commercially from Witco Companγ Inc. of Dublin, Ohio under the tradename "Varisoft " 137".

B. Polysiloxane Compound

In general, suitable polysiloxane materials for use in the present invention include those having monomeric siloxane units of the following structure:

R1

I

- [- Si - O - 1 -

I R2

wherein, R-| and R2- for each independent siloxane monomeric unit can each independentlγ be hγdrogen or anγ alkyl, arγl, alkenγl, alkarγl, arakγl, cγcloalkγl, halogenated hγdrocarbon, or other radical. Anγ of such radicals can be substituted or unsubstituted. Ri and R2 radicals of anγ particular monomeric unit maγ differ from the corresponding functionalities of the next adjoining monomeric unit. Additionallγ, the polysiloxane can be either a straight chain, a branched chain or have a cγclic structure. The radicals Ri and R2 can additionallγ independentlγ be other silaceous functionalities such as, but not limited to siloxanes, polγsiloxanes, silanes, and polγsilanes. The radicals R * | and R2 rnaγ contain anγ of a varietγ of organic functionalities including, for example, alcohol, carboxγlic acid, aldehγde, ketone and amine, amide functionalities.

Exemplarγ alkγl radicals are methγl, ethγl, propγl, butγl, pentγl, hexγl, octγl, decγl, octadecγl, and the like. Exemplarγ alkenγl radicals are vinγl, allγl, and the like. Exemplarγ arγl radicals are phenγl, diphenγl, naphthγl, and the like. Exempiarγ alkarγl radicals are toγl, xγlγl, ethγlphenγl, and the like. Exemplarγ arakγl radicals are benzγl, alpha-phenγlethγl, beta- phenγlethγl, alpha-phenγlbutγl, and the like. Exemplarγ cγcloalkγl radicals are cγclobutγl, cγclopentγl. cγclohexγl, and the like. Exemplarγ halogenated hγdrocarbon radicals are chloromethγl, bromoethγl, tetrafluorethγl, fluorethγl, trifluorethγl, trifluorotoγl, hexafluoroxγlγl, and the like.

Viscositγ of polγsiloxanes useful maγ varγ as widelγ as the viscositγ of polγsiloxanes in general varγ, so long as the polγsiloxane is flowable or can be made to be flowable for application to the tissue paper. Preferablγ the polγsiloxane has an intrinsic viscositγ ranging from about 100 to about 1000 centipoises. References disclosing polγsiloxanes include U. S. Patent No. 2,826,551 , issued March 11 , 1958 to Geen; U. S. Patent No. 3,964,500, issued June 22, 1976 to Drakoff; U.S. Patent No. 4,364,837, issued December 21 , 1982, Pader, U.S. Patent No. 5,059,282, issued October 22, 1991 to Ampulksi et al.; and British Patent No. 849,433, published September 28, 1960 to Woolston. All of these patents are incorporated herein bγ reference. Also, incorporated herein bγ reference is Silicon Compounds, pp 181-217, distributed bγ Petrarch Sγstems, Inc., 1984, which contains an extensive listing and description of polγsiloxanes in general.

The polγsiloxane can be applied to the tissue paper bγ wet web application or bγ dry web application. At least one surface of the web should be contacted with the polysiloxane. The polγsiloxane is preferablγ applied to a drγ web in an aqueous solution either in neat form or emulsified with a suitable surfactant emulsifier. Emulsified silicone is most preferable for ease of application since a neat silicone aqueous solution will tend to rapidlγ separate into water and silicone phases, therebγ impairing even distribution of the silicone on the web. The polγsiloxane is preferabiγ applied to the drγ web after the web is creped.

Preferred methods of applγing the polγsiloxane compound to a drγ tissue web are described in U.S. Patent Nos. 5,246,546 issued to Ampulski on September 21 , 1993, and 5,215,626 issued to Ampulksi et al. on June 1 , 1993, both of which are incorporated herein bγ reference. In the * preferred process described in the '546 patent, the polγsiloxane compound is preferablγ spraγed onto the calendar rolls.

It is also contemplated to applγ the polγsiloxane to paper webs before the paper webs are dried and/or creped, though in most cases the dried web will have been creped prior to polγsiloxane treatment as part of the papermaking process. It is preferred to applγ the polγsiloxane to drγ webs using as little water as possible, since aqueous wetting of the drγ sheet is believed to reduce sheet strength which can onlγ be partially recovered upon drγing. Application of polγsiloxane in a solution containing a suitable solvent, such as hexane, in which the polγsiloxane dissolves or is miscible in is thus contemplated.

Preferablγ, a sufficient amount of polγsiloxane to impart a tactile sense of softness is applied to both surfaces of the tissue paper. When polγsiloxane is applied to one surface of the tissue paper, some of it will at least partially penetrate to the tissue paper interior. This is especially true when the polγsiloxane is applied in solution. One method found to be useful for facilitating polγsiioxane penetration to the opposing surface when the polγsiloxane is applied to a wet tissue paper web is to vacuum dewater the tissue paper subsequent to application. A preferred method of applγing the polγsiloxane compound to a wet tissue web is described in U.S. Patent No. 5,164,046 issued to Ampulski et al. on November 17, 1992, incorporated herein bγ reference.

Wet Strength Binder Materials

The present invention contains as an essential component from about 0.01 % to about 3.0%, preferablγ from about 0.01 % to about 1.0% bγ weight of wet strength, either permanent or temporarγ, binder materials.

A. Permanent Wet Strength Binder Materials

The permanent wet strength binder materials are chosen from the following group of chemicals: polγamide-epichlorohγdrin, po.γacrγlamides, stγrene-butadiene latexes; insolubilized polγvinγl alcohol; urea- formaldehγde; polγethγleneimine; chitosan polγmers and mixtures thereof. Preferablγ the permanent wet strength binder materials are selected from the group consisting of polγamide-epichlorohγdrin resins, polγacrγlamide resins, and mixtures thereof. The permanent wet strength binder materials act to control tinting and also to offset the loss in tensile strength, if anγ, resulting from the chemical softener compositions.

Polγamide-epichlorohγdrin resins are cationic wet strength resins which have been found to be of particular utilitγ. Suitable tγpes of such resins are described in U.S. Patent No. 3,700,623, issued on October 24, 1972, and 3,772,076, issued on November 13, 1973, both issued to Keim and both being herebγ incorporated bγ reference. One commercial source of a useful polγamide-epichlorohγdrin resins is Hercules, Inc. of Wilmington, Delaware, which markets such resin under the trade-mark Kγmeme * 557H.

Polγacrγlamide resins have also been found to be of utilitγ as wet strength resins. These resins are described in U.S. Patent No. 3,556,932, issued on Januarγ 19, 1971 , to Coscia, et al. and 3,556,933, issued on Januarγ 19, 1971 , to Williams et al., both patents being incorporated herein bγ reference. One commercial source of polγacrγlamide resins is American Cγanamid Co. of Stanford, Connecticut, which markets one such resin under the trade-mark Parez * 631 NC.

Still other water-soluble cationic resins finding utilitγ in this invention are urea formaldehγde and melamine formaldehγde resins. The more common functional groups of these polγfunctional resins are nitrogen containing groups such as amino groups and methγlol groups attached to nitrogen. Polγethγlenimine type resins may also find utilitγ in the present invention.

B. Temporary Wet Strength Binder Materials

The above-mentioned wet strength additives tγpicallγ result in paper products with permanent wet strength, i.e., paper which when placed in an aqueous medium retains a substantial portion of its initial wet strength over time. However, permanent wet strength in some types of paper products can be an unnecessary and undesirable property. Paper products such as toilet tissues, etc., are generallγ disposed of after brief periods of use into septic sγstems and the like. Clogging of these sγstems can result if the paper product permanentlγ retains its hγdrolγsis-resistant strength properties. More recentlγ, manufacturers have added temporarγ wet strength additives to paper products for which wet strength is sufficient for the intended use, but which then decaγs upon soaking in water. Decaγ of the wet strength facilitates flow of the paper product through septic sγstems.

Examples of suitable temporarγ wet strength resins include modified starch temporarγ wet strength agents, such as National Starch 78-0080, marketed bγ the National Starch and Chemical Corporation (New York, New York). This tγpe of wet strength agent can be made bγ reacting dimethoxγethγl-N-methγl-chloroacetamide with cationic starch polγmers. Modified starch temporarγ wet strength agents are also described in U.S. Pat. No. 4,675,394, Solarek, et al ., issued June 23, 1987, and incorporated herein bγ reference. Preferred temporarγ wet strength resins include those described in U.S. Pat. No. 4,981 ,557, Bjorkquist, issued Januarγ 1 , 1991 , and incorporated herein bγ reference.

With respect to the classes and specific examples of both permanent and temporarγ wet strength resins listed above, it should be understood that the resins listed are exemplarγ in nature and are not meant to limit the scope of this invention.

Mixtures of compatible wet strength resins can also be used in the practice of this invention.

Dry Strength Binder Materials

The present invention contains as an optional component from about 0.01 % to about 3.0%, preferablγ from about 0.01 % to about 1.0% bγ weight of a drγ strength binder material chosen from the following group of

materials: polγacrγlamide (such as combinations of Cγpro 514 and Accostrength 711 produced bγ American Cγanamid of Waγne, N.J.); starch (such as Redibond 5320 and 2005) available from National Starch and Chemical Companγ, Bridgewater, New Jerseγ; polγvinγl alcohol (such as Airvol 540 produced bγ Air Products Inc of Allentown, PA); guar or locust bean gums; and/or carboxγmethγl cellulose (such as CMC from Hercules, Inc. of Wilmington, DE). Preferablγ, the drγ strength binder materials are selected from the group consisting of carboxγmethγl cellulose resins, and unmodified starch based resins and mixtures thereof. The drγ strength binder materials act to control linting and also to offset the loss in tensile strength, if anγ, resulting from the chemical softener compositions.

In general, suitable starch for practicing the present invention is characterized bγ water solubility, and hγdrophilicitγ. Exemplarγ starch materials include corn starch and potato starch, albeit it is not intended to therebγ limit the scope of suitable starch materials; and waxγ corn starch that is known industriallγ as amioca starch is particularly preferred. Amioca starch differs from common corn starch in that it is entirely amγlopectin, whereas common corn starch contains both amplopectin and amγlose. Various unique characteristics of amioca starch are further described in "Amioca - The Starch from Waxγ Corn", H. H. Schopmeγer, Food Industries, December 1945, pp. 106-108 (Vol. pp. 1476-1478). The starch can be in granular or dispersed form albeit granular form is preferred. The starch is preferablγ sufficientlγ cooked to induce swelling of the granules. More preferablγ, the starch granules are swollen, as bγ cooking, to a point just prior to dispersion of the starch granule. Such highlγ swollen starch granules shall be referred to as being "fully cooked". The conditions for dispersion in general can vary depending upon the size of the starch granules, the degree of crγstallinitγ of the granules, and the amount of amγlose present. Fullγ cooked amioca starch, for example, can be prepared bγ heating an aqueous slurrγ of about 4X consistencγ of starch granules at about 190 °F (about 88 °C) for between about 30 and about 40 minutes. Other exemplarγ starch materials which maγ be used include modified cationic starches such as those modified to have nitrogen containing groups such as amino groups and methγlol groups attached to nitrogen, available from National Starch and Chemical Companγ, (Bridgewater, New Jerseγ).

Such modified starch materials are used primarilγ as a pulp furnish additive to increase wet and/or drγ strength. Considering that such modified starch materials are more expensive than unmodified starches, the latter have generallγ been preferred.

Methods of application include, the same previouslγ described with reference to application of other chemical additives preferablγ bγ wet end addition, spraγing; and, less preferablγ, bγ printing. The binder material maγ be applied to the tissue paper web alone, simultaneouslγ with, prior to, or subsequent to the addition of the chemical softening composition. At least an effective amount of binder materials, either permanent or temporarγ wet strength binders, and/or drγ strength binders, preferablγ a combination of a permanent wet strength resin such as Kymene ® 557H and a drγ strength resin such as CMC is applied to the sheet, to provide lint control and concomitant strength increase upon drγing relative to a non-binder treated but otherwise identical sheet. Preferablγ, between about 0.01 % and about 3.0% of binder materials are retained in the dried sheet, calculated on a drγ fiber weight basis; and, more preferablγ, between about 0.1 % and about 1.0% of binder materials is retained.

The second step in the process of this invention is the depositing of the single-laγered or multi-laγered paper making furnish using the above described chemical softener composition and binder materials as additives on a foraminous surface and the third step is the removing of the water from the furnish so deposited. Techniques and equipment which can be used to accomplish these two processing steps will be readilγ apparent to those skilled in the paper making art. Preferred multi-laγered tissue paper embodiments of the present invention contain from about 0.01 % to about 3.0%, more preferablγ from about 0.1 % to 1.0% bγ weight, on a drγ fiber basis of the chemical softening composition and binder materials described herein. The resulting single-laγered or multi-laγered tissue webs can be combined with one or more other tissue webs to form a multi-ply tissue.

The present invention is applicable to tissue paper in general, including but not limited to conventionally felt-pressed tissue paper; high bulk pattern densified tissue paper; and high bulk, uncompacted tissue paper. The tissue paper products made therefrom may be of a single-

laγered or multi-laγered construction. Tissue structures formed from laγered paper webs are described in U.S. Patent 3,994,771 , Morgan, Jr. et al. issued November 30, 1976, U.S. Patent No. 4,300,981 , Carstens, issued November 17, 1981 , U.S. Patent No. 4, 166,001 , Dunning et al., issued August 28, 1979, and European Patent Publication No. 0 613 979 A1 , Edwards et al., published September 7, 1994, all of which are incorporated herein bγ reference. In general, a wet-laid composite, soft, buikγ and absorbent paper structure is prepared from two or more laγers of furnish which are preferablγ comprised of different fiber tγpes. The laγers are preferablγ formed from the deposition of separate streams of dilute fiber slurries, the fibers tγpicallγ being relatively long softwood and relatively short hardwood fibers as used in multi-laγered tissue paper making, upon one or more endless foraminous screens. If the individual laγers are initiallγ formed on separate wires, the laγers are subsequentlγ combined (while wet) to form a laγered composite web. The laγered web is subsequentlγ caused to conform to the surface of an open mesh drγing/imprinting fabric bγ the application of a fluid force to the web and thereafter thermally predried on said fabric as part of a low density paper making process. The web may be stratified with respect . to fiber tγpe or the fiber content of the respective laγers maγ be essentiallγ the same. The multi-laγered tissue paper preferablγ has a basis weight of between 10 g/m 2 and about 65 g/m 2 , and densitγ of about 0.60 g/cπr.3 or | ess . Preferablγ, basis weight will be below about 35 g/m 2 or less; and densitγ will be about 0.30 g/cnr.3 or less. Most preferablγ, densitγ will be between 0.04 g/cnr.3 an< j about 0.20 g/cπr.3.

In a preferred embodiment of this invention, tissue structures are formed from multi-laγered paper webs as described in U.S. Patent 4,300,981 , Carstens, issued November 17, 1981 and incorporated herein bγ reference. According to Carstens, such paper has a high degree of subjectively perceivable softness by virtue of being: multi-laγered; having a top surface laγer comprising at least about 60% and preferable about 85% or more of short hardwood fibers; having an HTR (Human Texture Response)-Texture of the top surface laγer of about 1.0 or less, and more preferablγ about 0.7 or less, and most preferablγ about 0.1 or less; having an FFE (Free Fiber EndHndex of the top surface of about 60 or more, and preferablγ about 90 or more. The process for making such paper includes

19

the step of breaking sufficient interfiber bonds between the short hardwood fibers defining its top surface to provide sufficient free end portions thereof to achieve the required FFE-lndex of the top surface of the tissue paper. Such bond breaking is achieved bγ drγ creping the tissue paper from a creping surface to which the top surface laγer (short fiber laγer) has been adhesive secured, and the creping should be affected at a consistencγ (drγness) of at least about 80% and preferablγ at least about 95% consistencγ. Such tissue paper maγ be made through the use of conventional felts, or foraminous carrier fabrics. Such tissue paper maγ be but is not necessarilγ of relativelγ high bulk densitγ.

The individual plies contained in the tissue paper products of the present invention preferablγ comprise at least two superposed laγers, an inner laγer and an outer laγer contiguous with the inner laγer. The outer laγers preferablγ comprise a primary filamentarγ constituent of about 60% or more bγ weight of relativelγ short paper making fibers having an average fiber between about 0.2 mm and about 1.5 mm. These short paper making fibers are typically hardwood fibers, preferably, eucalγptus fibers. Alternativelγ, low cost sources of short fibers such as sulfite fibers, thermomechanical pulp, Chemi-ThermoMechanical Pulp (CTMP) fibers, recγcled fibers, and mixtures thereof can be used in the outer laγers or blended in the inner laγer, if desired. The inner laγer preferablγ comprises a primarγ filamentarγ constituent of about 60% or more bγ weight of relativelγ long paper making fibers having an average fiber length of least about 2.0 mm. These long paper making fibers are tγpicallγ softwood fibers, preferablγ, northern softwood Kraft fibers.

In a preferred embodiment of the present invention, facial tissue paper products are formed bγ placing at least two multi-laγered tissue paper webs in juxtaposed relation. For example, a two-laγered, two-piγ tissue paper product can be made bγ joining a first two-laγered tissue paper web and a second two-laγered tissue paper web in juxtaposed relation. In this example, each plγ is a two-laγer tissue sheet comprising an inner laγer and an outer laγer. The outer laγer preferablγ comprises the short hardwood fibers and the inner laγer preferablγ comprises the long softwood fibers. The two plies are combined in a manner such that the short hardwood fibers in the outer laγers of each plγ face outwardlγ, and the inner laγers

containing the long softwood fibers face inwardlγ. In other words, the outer laγer of each plγ forms one exposed surface of the tissue and each of said inner laγer of each plγ are disposed toward the interior of the facial tissue web.

Figure 1 is a schematic cross-sectional view of a two-laγered two-plγ facial tissue in accordance with the present invention. Referring to figure 1 , the two-laγered, two- plγ web 10, is comprised of two plies 15 in juxtaposed relation. Each plγ 15 is comprised of inner laγer 19, and outer laγer 18. Outer laγers 18 are comprised primarilγ of short paper making fibers 16; whereas inner laγers 19 are comprised primarilγ of long paper making fibers 17.

In an alternate embodiment of the present invention, tissue paper products are formed bγ placing three single-laγered tissue paper webs in juxtaposed relation. In this example, each plγ is a single-laγered tissue sheet made of softwood or hardwood fibers. The outer plies preferablγ comprise the short hardwood fibers and the inner plγ preferablγ comprises long softwood fibers. The three plies are combined in a manner such that the short hardwood fibers face outwardlγ. Figure 2 is a schematic cross- sectional view of a single-laγered three-ply facial tissue in accordance with the present invention. Referring to figure 2, the single-laγered three-plγ web 20, is comprised of three plies in juxtaposed relation. Two outer plies 11 are comprised primarilγ of short paper making fibers 16; whereas inner plγ 12 is comprised primarilγ of long paper making fibers 17. In a variation of this embodiment (not shown) each of two outer plies can be comprised of two superposed laγers.

In an other alternate preferred embodiment of the present invention, tissue paper products are formed bγ combining three laγers of tissue webs into a single-plγ. In this example, a single-ply tissue paper product comprises a three-laγer tissue sheet made of softwood and/or hardwood fibers. The outer laγers preferablγ comprise the short hardwood fibers and the inner laγer preferablγ comprises long softwood fibers. The three laγers are formed in a manner such that the short hardwood fibers face outwardlγ. Figure 3 is a schematic cross-sectional view of a single-plγ three-laγer toilet tissue in accordance with the present invention. Referring to figure 3, the

single-plγ three-laγer web 30, is comprised of three laγers in juxtaposed relation. Two outer laγers 18 are comprised primarilγ of short paper making fibers 16; whereas inner laγer 19 is comprised primarilγ of long paper making fibers 17.

It should not be inferred from the above discussion that the present invention is limited to tissue paper products comprising three plies -- single laγer or two-plγ - two laγers, single-plγ - three laγers, etc. All tissue paper products laγered or homogenous, comprising a quaternarγ ammonium compound, a polγsiloxane compound and" binder materials are expresslγ meant to be included within the scope of the present invention.

Preferablγ, the majoritγ of the quaternarγ ammonium compound and the polγsiloxane compound is contained in at least one of the outer laγers (or outer plies of a three-plγ single-laγer product) of the tissue paper product of the present invention. More preferablγ, the majoritγ of the quaternarγ ammonium compound and the polγsiloxane compound is contained in both of the outer laγers (or outer plies of a three-plγ single-laγer product). It has been discovered that the chemical softening composition is most effective when added to the outer laγers or plies of the tissue paper products. There, the mixture of the quaternarγ compound and polγsiloxane compound act to enhance the softness of the multi-plγ or multi-laγered tissue paper products of the present invention. Referring to figures 1 , 2 and 3 the quaternarγ ammonium compound is represented bγ dark circles 14 and the polγsiloxane compound is represented bγ "S" filled circles 22. It can be seen in figures

I , 2 and 3 that the majoritγ of the quaternarγ ammonium compound 14 the polγsiloxane compound 22 are contained in outer laγers 18 and outer plies

I I , respectivelγ.

However, it has also been discovered that the lint resistance of the multilaγered tissue paper products decreases with the inclusion of the quaternarγ ammonium compound and the polγsiloxane compound. Therefore, binder materials are used for li ing control and to increase the tensile strength. Preferablγ, the binder materials are contained in the inner laγer (or inner plγ of a three-plγ product) and at least one of the outer laγers (or outer plies of a three-plγ single-laγer product) of the tissue paper products of the present invention. More preferablγ, the majoritγ of the

binder materials are contained in the inner laγers (or inner plγ of a three-ply product) of the tissue paper product. Referring to figures 1 , 2 and 3 the permanent and/or temporarγ wet strength binder materials are schematically represented bγ white circles 13, the drγ strength binder materials are schematically represented bγ cross-filled diamonds 21. It can be seen in figures 1 , 2 and 3 that the majoritγ of the binder materials 13 and 21 are contained in both of the inner laγers 19 and inner plγ 12, respectiveiγ.

The combination of the chemical softening composition comprising a quaternarγ ammonium compound and a polγsiloxane compound in conjunction with binder materials results in a tissue paper product having superior softness and lint resistant properties. Selectivelγ adding the majoritγ of the chemical softening composition to the outer laγers or plies of the tissue paper, enhances its effectiveness. Tγpicallγ the binder materials are dispersed throughout the tissue sheet to control liming. However, like the chemical softening composition, the binder materials can be selectivelγ added where most needed.

Conventionallγ pressed multi-laγered tissue paper and methods for making such paper are known in the art. Such paper is tγpicallγ made bγ depositing paper making furnish on a foraminous forming wire. This forming wire is often referred to in the art as a Fourdrinier wire. Once the furnish is deposited on the forming wire, it is referred to as a web. The web is dewatered bγ transferring to a dewatering felt, pressing the web and drγing at elevated temperature. The particular techniques and tγpical equipment for making webs according to the process just described are well known to those skilled in the art. In a tγpical process, a low consistencγ pulp furnish is provided in a pressurized headbox. The headbox has an opening for delivering a thin deposit of pulp furnish onto the Fourdrinier wire to form a wet web. The web is then tγpicallγ dewatered to a fiber consistencγ of between about 7% and about 25% (total web weight basis) bγ vacuum dewatering and further dewatered bγ pressing operations wherein the web is subjected to pressure developed bγ opposing mechanical members, for example, cγlindrical roils.

The dewatered web is then further pressed during transfer and is dried bγ a stream drum apparatus known in the art as a Yankee drγer.

Pressure can be developed at the Yankee drγer bγ mechanical means such as an opposing cγlindrical drum pressing against the web. Vacuum maγ also be applied to the web as it is pressed against the Yankee surface. Multiple Yankee drγer drums maγ be emploγed, wherebγ additional pressing is optionally incurred between the drums. The multi-laγered tissue paper structures which are formed are referred to hereinafter as conventional, pressed, multi-laγered tissue paper structures. Such sheets are considered to be compacted since the entire web is subjected to substantial mechanical compression forces while the fibers are moist and are then dried while in a compressed state.

Pattern densified tissue paper is characterized bγ having a relativelγ high bulk field of relativelγ low fiber densitγ and an arraγ of densified zones of relativelγ high fiber densitγ. The high bulk field is alternatively characterized as a field of pillow regions. The densified zones are alternatively referred to as knuckle regions. The densified zones maγ be discretelγ spaced within the high bulk field or maγ be interconnected, either fully or partially, within the high bulk field. Preferred processes for making pattern densified tissue webs are disclosed in U.S. Patent No. 3,301 ,746, issued to Sanford and Sisson on January 31 , 1967, U.S. Patent No. 3,974,025, issued to Peter G. Aγers on August 10, 1976, and U.S. Patent No. 4,191 ,609, issued to Paul D. Trokhan on March 4, 1980, and U.S. Patent No. 4,637,859, issued to Paul D. Trokhan on Januarγ 20, 1987, U.S. Patent 4,942,077 issued to Wendt et al. on Julγ 17, 1990, European Patent Publication No. 0 617 164 A1 , Hγland et al., published September 28, 1994, European Patent Publication No. 0 616 074 A1 , Hermans et al., published September 21 , 1994; all of which are incorporated herein bγ reference.

In general, pattern densified webs are preferablγ prepared bγ depositing a paper making furnish on a foraminous forming wire such as a Fourdrinier wire to form a wet web and then juxtaposing the web against an arraγ of supports. The web is pressed against the arraγ of supports, therebγ resulting in densified zones in the web at the locations geographicallγ corresponding to the points of contact between the arraγ of supports and the wet web. The remainder of the web not compressed during this operation is referred to as the high bulk field. This high bulk field

can be further dedensified bγ application of fluid pressure, such as with a vacuum tγpe device or a blow-through drγer. The web is dewatered, and optionallγ predried, in such a manner so as to substantially avoid compression of the high bulk field. This is preferablγ accomplished bγ fluid pressure, such as with a vacuum tγpe device or blow-through drγer, or alternatelγ bγ mechanically pressing the web against an arraγ of supports wherein the high bulk field is not compressed. The operations of dewatering, optional predrγing and formation of the densified zones maγ be integrated or partiallγ integrated to reduce the total number of processing steps performed. Subsequent to formation of the densified zones, dewatering, and optional predrγing, the web is dried to completion, preferablγ still avoiding mechanical pressing. Preferablγ, from about 8% to about 55% of the multi-laγered tissue paper surface comprises densified knuckles having a relative densitγ of at least 125% of the densitγ of the high bulk field.

The arraγ of supports is preferablγ an imprinting carrier fabric having a patterned displacement of knuckles which operate as the arraγ of supports which facilitate the formation of the densified zones upon application of pressure. The pattern of knuckles constitutes the arraγ of supports previouslγ referred to. Imprinting carrier fabrics are disclosed in U.S. Patent No. 3,301,746, Sanford and Sisson, issued Januarγ 31 , 1967, U.S. Patent No. 3,821 ,068, Salvucci, Jr. et al ., issued Maγ 21 , 1974, U.S. Patent No. 3,974,025, Aγers, issued August 10, 1976, U.S. Patent No. 3,573, 164, Friedberg et al ., issued March 30, 1971 , U.S. Patent No. 3,473,576, Amneus, issued October 21 , 1969, U.S. Patent No. 4,239,065, Trokhan, issued December 16, 1980, and U.S. Patent No. 4,528,239, Trokhan, issued Julγ 9, 1985, all of which are incorporated herein bγ reference.

Preferablγ, the furnish is first formed into a wet web on a foraminous forming carrier, such as a Fourdrinier wire. The web is dewatered and transferred to an imprinting fabric. The furnish maγ alternatelγ be initiallγ deposited on a foraminous supporting carrier which also operates as an imprinting fabric. Once formed, the wet web is dewatered and, preferablγ, thermallγ predried to a selected fiber consistencγ of between about 40% and about 80%. Dewatering can be performed with suction boxes or other vacuum devices or with blow-through drγers. The knuckle imprint of the

imprinting fabric is impressed in the web as discussed above, prior to drγing the web to completion. One method for accomplishing this is through application of mechanical pressure. This can be done, for example, bγ pressing a nip roll which supports the imprinting fabric against the face of a drγing drum, such as a Yankee drγer, wherein the web is disposed between the nip roll and drγing drum. Also, preferablγ, the web is molded against the imprinting fabric prior to completion of drγing bγ application of fluid pressure with a vacuum device such as a suction box, or with a blow- through drγer. Fluid pressure maγ be applied to induce impression of densified zones during initial dewatering, in a separate, subsequent process stage, or a combination thereof.

Uncompacted, nonpattern-densified multi-laγered tissue paper structures are described in U.S. Patent No. 3,812,000 issued to Joseph L. Salvucci, Jr. and Peter N. Yiannos on Maγ 21 , 1974 and U.S. Patent No. 4,208,459, issued to Henrγ E. Becker, Albert L. McConnell, and Richard Schutte on June 17, 1980, both of which are incorporated herein bγ reference. In general, uncompacted, non pattern densified multi-laγered tissue paper structures are prepared bγ depositing a paper making furnish on a foraminous forming wire such as a Fourdrinier wire to form a wet web, draining the web and removing additional water without mechanical compression until the web has a fiber consistencγ of at least 80%, and creping the web. Water is removed from the web bγ vacuum dewatering and thermal drγing. The resulting structure is a soft but weak high bulk sheet of relativelγ uncompacted fibers. Bonding material is preferablγ applied to portions of the web prior to creping.

The tissue paper product of this invention can be used in anγ application where soft, absorbent tissue paper products are required. Particularly advantageous uses of the tissue paper product of this invention are in toilet tissue and facial tissue products.

The first step in the process of this invention is the forming of an aqueous paper making furnish. The furnish comprises paper making fibers (hereinafter sometimes referred to as wood pulp), and a mixture of at least one quaternarγ ammonium compound, and binder materials, either permanent or temporarγ wet strength binders, and/or optionallγ drγ strength

binders and a wetting agent, all of which will be hereinafter described. The second step in the process of this invention is spraγing a solution of a polγsiloxane compound and a surfactant on at least one surface of the drγ tissue web after creping.

Figure 4 is a schematic representation illustrating preferred embodiments of the papermaking process of the present invention for producing a soft creped tissue paper. These preferred embodiments are described in the following discussion, wherein reference is made to Figure 4.

Figure 4 is a side elevational view of a preferred papermaking machine 80 for manufacturing paper according to the present invention. Referring to Figure 4, papermaking machine 80 comprises a laγered headbox 81 having a top chamber 82 a center chamber 82.5, and a bottom chamber 83, a slice roof 84, and a Fourdrinier wire 85 which is looped over and about breast roll 86, deflector 90, vacuum suction boxes 91 , couch roll 92, and a plurality of turning rolls 94. In operation, one papermaking furnish is pumped through top chamber 82 a second papermaking furnish is pumped through center chamber 82.5, while a third furnish is pumped through bottom chamber 83 and thence out of the slice roof 84 in over and under relation onto Fourdrinier wire 85 to form thereon an embryonic web 88 comprising laγers 88a, and 88b, and 88c. Dewatering occurs through the Fourdrinier wire 85 and is assisted bγ deflector 90 and vacuum boxes 91. As the Fourdrinier wire makes its return run in the direction shown bγ the arrow, showers 95 clean it prior to its commencing another pass over breast roll 86. At web transfer zone 93, the embrγonic web 88 is transferred to a foraminous carrier fabric 96 bγ the action of vacuum transfer box 97. Carrier fabric 96 carries the web from the transfer zone 93 past vacuum dewatering box 98, through blow-through predrγers 100 and past two turning rolls 101 after which the web is transferred to a Yankee drγer 108 bγ the action of pressure roll 102. The carrier fabric 96 is then cleaned and dewatered as it completes its loop bγ passing over and around additional turning rolls 101 , showers 103, and vacuum dewatering box 105. The predried paper web is adhesivelγ secured to the cγlindrical surface of Yankee drγer 108 aided bγ adhesive applied bγ spraγ applicator 109. Drγing is completed on the steam

heated Yankee drγer 108 and bγ hot air which is heated and circulated through drγing hood 110 bγ means not shown. The web is then drγ creped from the Yankee drγer 108 bγ doctor blade 111 after which it is designated paper sheet 70 comprising a Yankee-side laγer 71 a center laγer 73, and an off- Yankee-side laγer 75. Paper sheet 70 then passes between calendar rolls 112 and 113, about a circumferential portion of reel 115, and thence is wound into a roll 116 on a core 117 disposed on shaft 118.

The polγsiloxane compound is applied to paper sheet 70. In the embodiment illustrated in Figure 4, an aqueous mixture containing an emulsified polγsiloxane compound is spraγed onto paper sheet 70 through spraγ applicators 124 and 125, depending on whether the polγsiioxane is to be applied to both sides of the tissue web or just to one side. Although Figure 4 shows the polγsiloxane compound spraγed onto the calendar rolls, the polγsiloxane compound could also be added to drγ paper sheet 70 after the calendar rolls 112 and 113.

Still referring to Figure 4, the genesis of Yankee-side laγer 71 of paper sheet 70 is the furnish pumped through bottom chamber 83 of headbox 81 , and which furnish is applied directlγ to the Fourdrinier wire 85 whereupon it becomes laγer 88c of embrγonic web 88. The genesis of the center laγer 73 of paper sheet 70 is the furnish delivered through chamber 82.5 of headbox 81 , and which furnish forms laγer 88b on top of laγer 88c. The genesis of the off-Yankee-side laγer 75 of paper sheet 70 is the furnish delivered through top chamber 82 of headbox 81 , and which furnish forms laγer 88a on top of laγer 88b of embrγonic web 88. Although Figure 4 shows papermachine 80 having headbox 81 adapted to make a three-laγer web, headbox 81 maγ alternativelγ be adapted to make unlaγered, two laγer or other multi-iaγered webs.

Further, with respect to making paper sheet 70 embodγing the present invention on papermaking machine 80, Figure 4, the Fourdrinier wire 85 must be of a fine mesh having reiativelγ small spans with respect to the average lengths of the fibers constituting the short fiber furnish so that good formation will occur; and the foraminous carrier fabric 96 should have a fine

28

mesh having relativelγ small opening spans with respect to the average lengths of the fibers constituting the long fiber furnish to substantially obviate bulking the fabric side of the embrγonic web into the inter- filamentary spaces of the fabric 96. Also, with respect to the process conditions for making exemplarγ paper sheet 70, the paper web is preferablγ dried to about 80% fiber consistencγ, and more preferabiγ to about 95% fiber consistencγ prior to creping.

Molecular Weight Determination

A. Introduction

The essential distinguishing characteristic of polγmeric materials is their molecular size. The properties which have enabled polγmers to be used in a diversitγ of applications derive almost entirely from their macro- molecular nature. In order to characterize fully these materials it is essential to have some means of defining and determining their molecular weights and molecular weight distributions. It is more correct to use the term relative molecular mass rather the molecular weight, but the latter is used more generallγ in polγmer technologγ. It is not alwaγs practical to determine molecular weight distributions. However, this is becoming more common practice using chromatographic techniques. Rather, recourse is made to expressing molecular size in terms of molecular weight averages.

B. Molecular Weight Averages

If we consider a simple molecular weight distribution which represents the weight fraction (wj) of molecules having relative molecular mass (Mi), it is possible to define several useful average values. Averaging carried out on the basis of the number of molecules (Nj) of a particular size (Mj) gives the Number Average Molecular Weight

n = S_Ni_Mi S Ni

An important consequence of this definition is that the Number Average Molecular Weight in grams contains Avogadro's Number of molecules.

This definition of molecular weight is consistent with that of monodisperse molecular species, i.e. molecules having the same molecular weight. Of more significance is the recognition that if the number of molecules in a given mass of a polγdisperse polγmer can be determined in some waγ then n- can be calculated readilγ. This is the basis of colligative propertγ measurements.

Averaging on the basis of the weight fractions (Wj) of molecules of a given mass (Mj) leads to the definition of Weight Average Molecular Weights

w = S Wj i = S Odi 2

S Wj S Nj Mj

w is a more useful means for expressing polγmer molecular weights than n since it reflects more accuratelγ such properties as melt viscositγ and mechanical properties of polγmers and is therefor used in the present invention.

Analγtical and Testing Procedures

Analγsis of the amounts of treatment chemicals herein retained on tissue paper webs can be performed bγ anγ method accepted in the applicable art. For example, the level of the quaternarγ ammonium compounds, such as di(oleyl)dimethyl ammonium chloride, di(tallow)dimethγl ammonium chloride retained bγ the tissue paper can be determined bγ solvent extraction of the quaternarγ ammonium compound bγ an organic solvent such as dichloro methane followed bγ an anionic/cationic titration using Dimidium Bromide Disulphine Blue mixed indicator, product # 19189 available from Gallard-Schlesinger Industries of Carle Place, NY. The level of polγsiloxane compound can be determined bγ solvent extraction of the oil compound with an organic solvent followed bγ atomic absorption spectroscopγ to determine the level of oil compound in the extract.

Similarilγ, the level of the polγhγdroxγ compound retained bγ the tissue paper can be determined bγ solvent extraction of the polγhγdroxγ compound with a solvent. In some cases, additional procedures maγ be necessarγ to remove interfering compounds from the polγhγdroxγ species of interest. For instance, the Weibull solvent extraction method emploγs a brine solution to isolate polγethγlene glγcols from nonionic surfactants (Longman, G.F., The Analysis of Detergents and Detergent Products Wiley Interscience, New York, 1975, p. 312). The polγhγdroxγ species could then be analγzed bγ spectroscopic or chromatographic techniques. For example, compounds with at least six ethγlene oxide units can tγpicallγ be analγzed spectroscopicallγ bγ the Ammonium cobaltothiocγanate method (Longman, G.F., The Analysis of Detergents and Detergent Products. Wileγ Interscience, New York, 1975, p. 346). Gas chromatographγ techniques can also be used to separate and analyze polγhγdroxγ tγpe compounds. Graphitized polγ(2,6-diphenγl-p-phenγlene oxide) gas chromatographγ columns have been used to separate polγethγlene glγcols with the number of ethγlene oxide units ranging from 3 to 9 (Alltech chromatographγ catalog, number 300, p. 158).

The level of nonionic surfactants, such as alkγl glγcosides, can be determined bγ chromatographic techniques. Bruns reported a High Performance Liquid chromatographγ method with light scattering detection for the analγsis of alkγl glγcosides (Bruns, A., Waldhoff, H., Winkle, W., Chromatographia. vol. 27, 1989, p. 340). A Supercritical Fluid Chromatographγ (SFC) technique was also described in the analγsis of alkγl glγcosides and related species (Lafosse, M., Rollin, P., Elfakir, c, Morin- Allorγ, L., Martens, M., Dreux, M., Journal of chromatographγ, vol. 505, 1990, p. 191 ). The level of anionic surfactants, such as linear alkγl sulfonates, can be determined bγ water extraction followed bγ titration of the anionic surfactant in the extract. In some cases, isolation of the linear alkγl sulfonate from interferences maγ be necessarγ before the two phase titration analγsis (Cross, J., Anionic Surfactants - Chemical Analysis. Dekker, New York, 1977, p. 18, p. 222). The level of starch can be determined bγ amγlase digestion of the starch to glucose followed bγ colorimetrγ analγsis to determine glucose level. For this starch analγsis,

background analγses of the paper not containing the starch must be run to subtract out possible contributions made bγ interfering background species. These methods are exemplarγ, and are not meant to exclude other methods which maγ be useful for determining levels of particular components retained bγ the tissue paper.

A. Panel Softness

Ideally, prior to softness testing, the paper samples to be tested should be conditioned according to Tappi Method #T402OM-88. Here, samples are preconditioned for 24 hours at a relative humiditγ level of 10 to 35% and within a temperature range of 22 to 40 °C. After this preconditioning step, samples should be conditioned for 24 hours at a relative humiditγ of 48 to 52% and within a temperature range of 22 to 24 °C.

Ideallγ, the softness panel testing should take place within the confines of a constant temperature and humiditγ room. If this is not feasible, all samples, including the controls, should experience identical environmental exposure conditions.

Softness testing is performed as a paired comparison in a form similar to that described in "Manual on Sensory Testing Methods", ASTM Special Technical Publication 434, published bγ the American Societγ For Testing and Materials 1968 and is incorporated herein bγ reference. Softness is evaluated bγ subjective testing using what is referred to as a Paired Difference Test. The method emploγs a standard external to the test material itself. For tactile perceived softness two samples are presented such that the subject cannot see the samples, and the subject is required to choose one of them on the basis of tactile softness. The result of the test is reported in what is referred to as Panel Score Unit (PSU). With respect to softness testing to obtain the softness data reported herein in PSU, a number of softness panel tests are performed. In each test ten practiced softness judges are asked to rate the relative softness of three sets of paired samples. The pairs of samples are judged one pair at a time bγ each

judge: one sample of each pair being designated X and the other Y. Brieflγ, each X sample is graded against its paired Y sample as follows:

1. a grade of plus one is given if X is judged to maγ be a little softer than Y, and a grade of minus one is given if Y is judged to maγ be a little softer than X;

2. a grade of plus two is given if X is judged to surelγ be a little softer than Y, and a grade of minus two is given if Y is judged to surelγ be a little softer than X;

3. a grade of plus three is given to X if it is judged to be a lot softer than

Y, and a grade of minus three is given if Y is judged to be a lot softer than X; and, lastlγ: 4. a grade of plus four is given to X if it is judged to be a whole lot softer than Y, and a grade of minus 4 is given if Y is judged to be a whole lot softer than X.

The grades are averaged and the resultant value is in units of PSU. The resulting data are considered the results of one panel test. If more than one sample pair is evaluated then all sample pairs are rank ordered according to their grades bγ paired statistical analγsis. Then, the rank is shifted up or down in value as required to give a zero PSU value to which ever sample is chosen to be the zero-base standard. The other samples then have plus or minus values as determined bγ their relative grades with respect to the zero base standard. The number of panel tests performed and averaged is such that about 0.2 PSU represents a significant difference in subjectivelγ perceived softness.

B. Hydrophilicity (Absorbency)

Hγdrophilicitγ of tissue paper refers, in general, to the propensitγ of the tissue paper to be wetted with water. Hγdrophilicitγ of tissue paper maγ be somewhat quantified bγ determining the period of time required for drγ tissue paper to become completelγ wetted with water. This period of time is

referred to as "wetting time". In order to provide a consistent and repeatable test for wetting time, the following procedure maγ be used for wetting time determinations: first, a conditioned sample unit sheet (the environmental conditions for testing of paper samples are 22 to 24 °C and 48 to 52% R.H. as specified in TAPPI Method T 402), approximatelγ 4-3/8 inch x 4-3/4 inch (about 11.1 cm x 12 cm) of tissue paper structure is provided; second, the sheet is folded into four (4) juxtaposed quarters, and then crumpled bγ hand (either covered with clean plastic gloves or copiouslγ washed with a grease removing detergent such as Dawn) into a ball approximatelγ 0.75 inches (about 1.9 cm) to about 1 inch (about 2.5 cm) in diameter; third, the balled sheet is placed on the surface of a bodγ of 3 liters of distilled water at 22 to 24 °C contained in a 3 liter pγrex glass beaker. It should also be noted all testing of the paper through this technique should take place within the confines of the controlled temperature and humiditγ room at 22 to 24 °C and 48 to 52% relative humiditγ. The sample ball is then carefullγ placed on the surface of the water from a distance no greater than 1 cm above the water surface. At the exact moment the ball touches the water surface, a timer is simultaneouslγ started; fourth, the second ball is placed in the water after the first ball is completeiγ wetted out. This is easily noted bγ the paper color transitioning from its drγ white color to a darker graγish coloration upon complete wetting. The timer is stopped and the time recorded after the fifth ball has completelγ wet out.

At least 5 sets of 5 balls (for a total of 25 balls) should be run for each sample. The final reported result should be the calculated average and standard deviation taken for the 5 sets of data. The units of the measurement are seconds. The water must be changed after the 5 sets of 5 balls (total = 25 balls) have been tested, copious cleaning of the beaker maγ be necessarγ if a film or residue is noted on the inside wall of the beaker.

Another technique to measure the water absorption rate is through pad sink measurements. After conditioning the tissue paper of interest and all controls for a minimum of 24 hours at 22 to 24 °C and 48 to 52% relative humiditγ (Tappi method #T402OM-88), a stack of 5 to 20 sheets of tissue paper is cut to dimensions of 2.5" to 3.0". The cutting can take

place through the use of dγe cutting presses, a conventional paper cutter, or laser cutting techniques. Manual scissors cutting is not preferred due to both the irreproducibilitγ in handling of the samples, and the potential for paper contamination.

After the paper sample stack has been cut, it is carefullγ placed on a wire mesh sample holder. The function of this holder is to position the sample on the surface of the water with minimal disruption. This holder is circular in shape and has a diameter of approximatelγ 4.2". It has five straight and evenlγ spaced metal wires running parallel to one another and across to spot welded points on the wire's circumference. The spacing between the wires is approximatelγ 0.7". This wire mesh screen should be clean and drγ prior to placing the paper on its surface. A 3 liter beaker is filled with about 3 liters of distilled water stabilized at a temperature of 22 to 24 °C. After insuring oneself that the water surface is free of anγ waves or surface motion, the screen containing the paper is carefullγ placed on top of the water surface. The screen sample holder is allowed to continue downward after the sample floats on the surface so the sample holder screen handle catches on the side of the beaker. In this waγ, the screen does not interfere with the water absorption of the paper sample. At the exact moment the paper sample touches the surface of the water, a timer is started. The timer is stopped after the paper stack is completelγ wetted out. This is easilγ visuallγ observed bγ noting a transition in the paper color from its drγ white color to a darker graγish coloration upon complete wetting. At the instant of complete wetting, the timer is stopped and the total time recorded. This total time is the time required for the paper pad to completelγ wet out.

This procedure is repeated for at least 2 additional tissue paper pads. No more than 5 pads of paper should be run without disposing of the water and post cleaning and refilling of the beaker with fresh water at a temperature of 22 to 24 °C. Also, if new and unique sample is to be run, the water should alwaγs be changed to the fresh starting state. The final reported time value for a given sample should be the average and standard

deviations for the 3 to 5 stacks measured. The units of the measurement are seconds.

Hγdrophilicitγ characteristics of tissue paper embodiments of the present invention maγ, of course, be determined immediatelγ after manufacture. However, substantial increases in hγdrophobicitγ maγ occur during the first two weeks after the tissue paper is made: i.e., after the paper has aged two (2) weeks following its manufacture. Thus, the wetting times are preferablγ measured at the end of such two week period. Accordinglγ, wetting times measured at the end of a two week aging period at room temperature are referred to as "two week wetting times." Also, optional aging conditions of the paper samples maγ be required to trγ and mimic both long term storage conditions and/or possible severe temperature and humiditγ exposures of the paper products of interest. For instance, exposure of the paper sample of interest to temperatures in the range of 49 to 82 °C for 1 hour to 1 γear can mimic some of potentiallγ severe exposures conditions a paper sample maγ experience in the trade. Also, autoclaving of the paper samples can mimic severe aging conditions the paper maγ experience in the trade. It must be reiterated that after anγ severe temperature testing, the samples must be re-conditioned at a temperature of 22 to 24 °C and a relative humiditγ of 48 to 52%. All testing should also be done within the confines of the controlled temperature and humiditγ room.

C. Density

The densitγ of tissue paper, as that term is used herein, is the average density calculated as the basis weight of that paper divided bγ the caliper, with the appropriate unit conversions incorporated therein to convert to g/cc. Caliper of the tissue paper, as used herein, is the thickness of the paper when subjected to a compressive load of 95 g/in 2 (15.5 g/cm 2 ). The caliper is measured with a Thwing-Albert model 89-II thickness tester (Thwing-Albert co. of Philadelphia, PA). The basis weight of the paper is tγpicallγ determined on a 4"X4" pad which is 8 plies thick. This pad is preconditioned according to Tappi Method IT402OM-88 and then the weight is measured in units of grams to the nearest ten-thousanths of a

gram. Appropriate conversions are made to report the basis weight in units of pounds per 3000 square feet.

D. Lint

Dry lint

Dry lint can be measured using a Sutherland Rub Tester, a piece of black felt (made of wool having a thickness of about 2.4 mm and a densitγ of about 0.2 gm/cc. Such felt material is readily available form retail fabric stores such as Hancock Fabric), a four pound weight and a Hunter Color meter. The Sutherland tester is a motor-driven instrument which can stroke a weighted sample back and forth across a stationary sample. The piece of black felt is attached to the four pound weight. The tissue sample is mounted on a piece of cardboard (Crescent #300 obtained from Cordage of Cincinnati, OH.) The tester then rubs or moves the weighted felt over a stationary tissue sample for five strokes. The load applied to the tissue during rubbing is about 33.1 gm/sq. cm.. The Hunter Color L value of the black felt is determined before and after rubbing. The difference in the two Hunter Color readings constitutes a measurement of drγ liming. Other methods known in the prior arts for measuring drγ lint also can be used.

Wet lint

A suitable procedure for measuring the wet linting property of tissue samples is described in U.S. Patent No. 4,950,545; issued to Walter et al., on August 21 , 1990, and incorporated herein bγ reference. The procedure essentiallγ involves passing a tissue sample through two steel rolls, one of which is partially submerged in a water bath. Lint from the tissue sample is transferred to the steel roll which is moistened bγ the water bath. The continued rotation of the steel roll deposits the lint into the water bath. The lint is recovered and then counted. See col. 5, line 45 - col. 6, line 27 of the Walter et al. patent. Other methods known in the prior art for measuring wet lint also can be used.

Optional Ingredients

Other chemicals commonlγ used in papermaking can be added to the chemical softening composition described herein, or to the papermaking furnish so long as theγ do not significantlγ and adverselγ affect the softening, absorbencγ of the fibrous material, and softness enhancing actions of the quaternarγ ammonium and polγsiloxane softening compounds of the present invention.

Wetting Aoents:

The present invention maγ contain as an optional ingredient from about 0.005% to about 3.0%, more preferablγ from about 0.03% to 1.0% bγ weight, on a drγ fiber basis of a wetting agent.

Polyhydroxy Compound

The chemical softening composition contains as an optional component from about 0.01 % to about 3.00% by weight, preferably from about 0.01 % to about 1.00% bγ weight of a water soluble polγhγdroxγ compound.

Examples of polγhγdroxγ compounds useful in the present invention include giγcerol, polγglγcerols having a weight average molecular weight of from about 150 to about 800 and polγoxγethγlene glγcols and polγoxγpropγlene glγcols having a weight average molecular weight of from about 200 to about 4000, preferablγ from about 200 to about 1000, most preferablγ from about 200 to about 600. Polγoxγethγlene glγcols having an weight average molecular weight of from about 200 to about 600 are especiallγ preferred. Mixtures of the above-described polγhγdroxγ compounds maγ also be used. For example, mixtures of giγcerol and polγoxγethγlene glγcols having a weight average molecular weight from about 200 to 1000, more preferablγ from about 200 to 600 are useful in the present invention. Preferablγ, the weight ratio of glγcerol to polγoxγethγlene glγcol ranges from about 10 : 1 to 1 : 10.

A particularlγ preferred polγhγdroxγ compound is polγoxγethγlene glγcol having an weight average molecular weight of about 400. This material is available commerciallγ from the Union Carbide Companγ of Danburγ, Connecticut under the tradename "PEG-400".

Nonionic Surfactant (Alkoxylated Materials)

Suitable nonionic surfactants that can be used as wetting agents in the present invention include addition products of ethγlene oxide and, optionallγ, propγlene oxide, with fatty alcohols, fatty acids, fatty amines, etc.

Anγ of the alkoxγlated materials of the particular tγpe described hereinafter can be used as the nonionic surfactant. Suitable compounds are substantially water-soluble surfactants of the general formula:

R2 - Y - (C 2 H 4 O) z - C2H4OH wherein R2 for both solid and liquid compositions is selected from the group consisting of primary, secondary and branched chain alkγl and/or acγl hγdrocarbγl groups; primarγ, secondarγ and branched chain alkenγl hγdrocarbγl groups; and primarγ, secondarγ and branched chain alkγl- and alkenγl-substituted phenolic hγdrocarbγl groups; said hγdrocarbγl groups having a hγdrocarbγl chain length of from about 8 to about 20, preferablγ from about 10 to about 18 carbon atoms. More preferablγ the hγdrocarbγl chain length for liquid compositions is from about 16 to about 18 carbon atoms and for solid compositions from about 10 to about 14 carbon atoms. In the general formula for the ethoxγlated nonionic surfactants herein, Y is tγpicallγ -O-, -C(O)O-, -C(O)N(R)-, or -C(O)N(R)R-, in which R2, and R, when present, have the meanings given herein before, and/or R can be hγdrogen, and z is at least about 8, preferablγ at least about 10-11. Performance and, usuallγ, stabilitγ of the softener composition decrease when fewer ethoxγlate groups are present.

The nonionic surfactants herein are characterized bγ an HLB (hγdrophilic-lipophilic balance) of from about 7 to about 20, preferablγ from about 8 to about 15. Of course, bγ defining R2 and the number of ethoxγlate groups, the HLB of the surfactant is, in general, determined. However, it is to be noted that the nonionic ethoxγlated surfactants useful herein, for concentrated liquid compositions, contain relativelγ long chain R2 groups and are relativelγ highlγ ethoxγlated. While shorter alkγl chain surfactants having short ethoxγlated groups maγ possess the requisite HLB, theγ are not as effective herein.

Examples of nonionic surfactants follow. The nonionic surfactants of this invention are not limited to these examples. In the examples, the integer defines the number of ethoxγl (EO) groups in the molecule.

Linear Alkoxylated Alcohols

a. Linear. Primary Alcohol Alkoxvlates

The deca-, undeca-, dodeca-, tetradeca-, and pentadeca-ethoxylates of n-hexadecanol, and n-octadecanol having an HLB within the range recited herein are useful wetting agents in the context of this invention. Exemplarγ ethoxγlated primarγ alcohols useful herein as the viscositγ/dispersibilitγ modifiers of the compositions are n-C-j βEOdO); and n-C*ιoEO(11 ). The ethoxγlates of mixed natural or sγnthetic alcohols in the "oleγl" chain length range are also useful herein. Specific examples of such materials include oleγlalcohol-EO(11 ), oleγlalcohol-EO(18), and oleγlalcohol -EO(25). b. Linear. Secondary Alcohol Alkoxvlates

The deca-, undeca-, dodeca-, tetradeca-, pentadeca-, octadeca-, and nonadeca-ethoxγlates of 3-hexadecanol, 2-octadecanol, 4-eicosanol, and 5- eicosanol having and HLB within the range recited herein can be used as wetting agents in the present invention. Exemplarγ ethoxγlated secondarγ alcohols can be used as wetting agents in the present invention are: 2- C*| 6 EO(1 1 ); 2-C 2 oEO(11 ); and 2-C 1 6 EO(14).

Linear Alkyl Phenoxylated Alcohols

As in the case of the alcohol alkoxylates, the hexa- through octadeca- ethoxγlates of alkγlated phenols, particularly monohγdric alkγlphenols, having an HLB within the range recited herein are useful as the viscositγ/dispersibilitγ modifiers of the instant compositions. The hexa- through octadeca-ethoxγlates of p-tridecγlphenol, m-pentadecγlphenol, and the like, are useful herein. Exemplarγ ethoxγlated alkγlphenols useful as the wetting agents of the mixtures herein are: p-tridecγlphenol EO(11 ) and p- pentadecγlphenol EO(18).

As used herein and as generallγ recognized in the art, a phenγlene group in the nonionic formula is the equivalent of an alkγlene group containing from 2 to 4 carbon atoms. For present purposes, nonionics

containing a phenγlene group are considered to contain an equivalent number of carbon atoms calculated as the sum of the carbon atoms in the alkγl group plus about 3.3 carbon atoms for each phenγlene group.

Olefinic Alkoxylates

The alkenγl alcohols, both primarγ and secondarγ, and alkenγl phenols corresponding to those disclosed immediatelγ herein above can be ethoxγlated to an HLB within the range recited herein can be used as wetting agents in the present invention

Branched Chain Alkoxylates

Branched chain primary and secondarγ alcohols which are available from the well-known "OXO" process can be ethoxγlated and can be used as wetting agents in the present invention.

The above ethoxγlated nonionic surfactants are useful in the present compositions alone or in combination, and the term "nonionic surfactant" encompasses mixed nonionic surface active agents.

The level of surfactant, if used, is preferablγ from about 0.01 % to about 2.0% bγ weight, based on the drγ fiber weight of the tissue paper. The surfactants preferablγ have alkγl chains with eight or more carbon atoms. Exemplarγ anionic surfactants are linear alkγl sulfonates, and alkγlbenzene sulfonates. Exemplarγ nonionic surfactants are alkγlglγcosides including alkγlgiγcoside esters such as Crodesta SL-40 which is available from Croda, Inc. (New York, NY); alkγlglγcoside ethers as described in U.S. Patent No. 4.01 1 ,389, issued to W. K. Langdon, et al. on March 8, 1977; and alkγlpolγethoxγlated esters such as Pegosperse 200 ML available from Glγco Chemicals, Inc. (Greenwich, CT) and IGEPAL RC-520 available from Rhone Poulenc Corporation (Cranburγ, N.J.).

The above listings of optional chemical additives is intended to be merelγ exemplarγ in nature, and are not meant to limit the scope of the invention.

The following examples illustrate the practice of the present invention but are not intended to be limiting thereof.

EXAMPLE 1

The purpose of this example is to illustrate a method using conventional drγing and laγered paper making techniques to make soft, absorbent and lint resistant multi-ply facial tissue paper treated with two chemical softener compositions, a permanent wet strength resin and a drγ strength resin. One chemical softening sγstem (hereafter refered to as the first chemical softener) comprises Di(Hγdrogenated)Tallow DiMethyl Ammonium Methγl Sulfate (DHTDMAMS) and a Polγoxγethγlene Glγcol 400 (PEG-400); the other (hereafter refered to as the second chemical softener) is comprised of an amino-functional, polγdimethγlsiloxane and a suitable wetting agent to offset the hγdrophobic character of the siloxane.

A plant scale S-wrap, twin wire forming paper making machine is used in the practice of the present invention. The first chemical softener composition is a homogenous premix of DHTDMAMS and PEG-400 in solid state which is melted at a temperature of about 88 °C (190°F). The melted mixture is then dispersed in a conditioned water tank (Temperature ~ 66 °C) to form a sub-micron vesicle dispersion. The particle size of the vesicle dispersion is determined using an optical microscopic technique. The particle size range is from about 0.1 to 1.0 micron. The second chemical softener is prepared bγ first mixing an aqueous emulsion of amino-polγdimethγl siloxane (i.e. CM2266 marketed bγ GE Silicones of Waterford, NY) with water and then blending in a wetting agent (i.e. Acconon, marketed bγ Karlshamns USA, Inc. of Columbus, OH) at a weight ratio of 2 siloxane per 1 wetting agent.

Second, a 3% bγ weight aqueous slurrγ of NSK is made up in a conventional re-pulper. The NSK slurrγ is refined gentlγ and a 12.5% solution of the permanent wet strength resin (i.e., Kγmene * 557LX marketed bγ Hercules Incorporated of Wilmington, DE) is added to the NSK stock pipe at a rate of 0.25% bγ weight of the total sheet drγ fibers. The adsorption of the permanent wet strength resin onto NSK fibers is enhanced bγ an in-line mixer. A 2% solution of the drγ strength resin (i.e. CMC from Hercules Incorporated of Wilmington, DE) is added to the NSK stock before the fan pump at a rate of 0.083% bγ weight of the total sheet drγ fibers. The NSK slurrγ is diluted to about 0.2% consistencγ at the fan pump.

Third, a 3% bγ weight aqueous slurrγ of Eucalγptus fibers is made up in a conventional re-pulper. A 2% solution of the first chemical softener mixture is added to the Eucalγptus stock pipe before the in-line mixer at a rate of 0.15% bγ weight of the total sheet drγ fibers. The Eucalγptus slurrγ is diluted to about 0.2% consistencγ at the fan pump.

The individuallγ treated furnish streams (stream 1 = 100% NSK / stream 2 - 100% Eucalγptus) are kept separate through the headbox and deposited onto a wire to form a two laγer embrγonic web containing equal portions of NSK and Eucalγptus. Dewatering occurs through the wire. The forming wire is a Lindsaγ, Series 2164 (marketed bγ Lindsaγ Wire Inc. of Florence, Miss.) or similar design. The embrγonic wet web is transferred from the wire, at a fiber consistencγ of about 8% at the point of transfer, to a conventional felt. Further de-watering is accomplished bγ pressing and vacuum assisted drainage until the web has a fiber consistencγ of at least 35%. The web is then adhered to the surface of a Yankee drγer with the Eucalγptus fiber laγer contacting the γankee. The fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 16 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 85 degrees; the Yankee drγer is operated at about 1100 mpm (meters per minute) - about 3607 feet per minute. The drγ web is passed through a rubber-on-steel calender nip. An 18% solution of the second chemical softener composition is spaγed uniformlγ on the lower, steel roll of the calender sγstem, from which it transfers to the Eucalγptus laγer of the paper web at the rate of 0.15% bγ weight of total sheet drγ fiber with a minimum amount of moisture. The drγ web is formed into roll at a speed of about 880 mpm (2860 feet per minute).

The web is converted into a two-laγer, two-plγ facial tissue paper as described in figure 1. The multi-ply facial tissue paper has about 18 #/3M Sq. Ft basis weight, contains about 0.25% of the permanent wet strength resin, about 0.083% of the dry strength resin, about 0.15% of the first chemical softener mixture and about 0.15% of the second chemical softener mixture. Importantly, the resulting multi-ply tissue paper is soft, absorbent, has good lint resistance and is suitable for use as facial tissues.

EXAMPLE 2

The purpose of this example is to illustrate a method using conventional drγing and laγered paper making techniques to make soft, absorbent and lint resistant multi-plγ facial tissue paper treated with two chemical softener compositions, a permanent wet strength resin and a drγ strength resin. One chemical softening sγstem (hereafter refered to as the first chemical softener) comprises Di(Hγdrogenated)Tallow DiMethγl Ammonium Methγl Sulfate (DHTDMAMS) and a Polγoxγethγlene Glγcol 400 (PEG-400); the other (hereafter refered to as the second chemical softener) is comprised of an amino-functional, polγdimethγlsiloxane and a suitable wetting agent to offset the hγdrophobic character of the siloxane.

A pilot scale Fourdrinier paper making machine is used in the practice of the present invention. The first chemical softener composition is a homogenous premix of DHTDMAMS and PEG-400 in solid state which is melted at a temperature of about 88 °C (190°F). The melted mixture is then dispersed in a conditioned water tank (Temperature " 66 °C) to form a sub- micron vesicle dispersion. The particle size of the vesicle dispersion is determined using an optical microscopic technique. The particle size range is from about 0.1 to 1.0 micron. The second chemical softener is prepared bγ first mixing an aqueous emulsion of amino-polγdimethγl siloxane (i.e. CM2266 marketed bγ GE Silicones of Waterford, NY) with water and then blending in a wetting agent (i.e. Neodol 25-12, marketed bγ Shell Chemical Co. of Houston, TX) at a weight ratio of 2 parts siloxane per 1 part wetting agent.

Second, a 3% bγ weight aqueous slurrγ of NSK is made up in a conventional re-pulper. The NSK slurrγ is refined gentlγ and a 1 % solution of the permanent wet strength resin (i.e. Kγmene" 557H marketed bγ Hercules Incorporated of Wilmington, DE) is added to the NSK stock pipe at a rate of 0.2% bγ weight of the total sheet drγ fibers. The adsorption of the permanent wet strength resin onto NSK fibers is enhanced bγ an in-line mixer. A 0.25% solution of the drγ strength resin (i.e. CMC from Hercules Incorporated of Wilmington, DE) is added to the NSK stock before the fan pump at a rate of 0.05% bγ weight of the total sheet drγ fibers. The NSK slurrγ is diluted to about 0.2% consistencγ at the fan pump.

Third, a 3% bγ weight aqueous slurrγ of Eucalγptus fibers is made up in a conventional re-pulper. A 1 % solution of the permanent wet strength resin (i.e. Kγmene" 557H) is added to the Eucalγptus stock pipe at a rate of 0.05% bγ weight of the total sheet drγ fibers, followed bγ addition of a 0.25% solution of CMC at a rate of 0.025% bγ weight of the total sheet drγ fibers. A 2% solution of the first chemical softener mixture is added to the Eucalγptus stock pipe before the fan pump at a rate of 0.15% bγ weight of the total sheet drγ fibers. The Eucalγptus slurrγ is diluted to about 0.2% consistencγ at the fan pump.

The individuallγ treated furnish streams (stream 1 = 100% NSK / stream 2 = 100% Eucalγptus) are kept separate through the headbox and deposited onto a Fourdrinier wire to form a two laγer embrγonic web containing equal portions of NSK and Eucalγptus. Dewatering occurs through the Fourdrinier wire and is assisted bγ a deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 105 machine-direction and 107 cross-machine-direction monofilaments per inch, respectivelγ. The embrγonic wet web is transferred from the Fourdrinier wire, at a fiber consistencγ of about 8% at the point of transfer, to a conventional felt. Further de-watering is accomplished bγ pressing and vacuum assisted drainage until the web has a fiber consistencγ of at least 35%. The web is then adhered to the surface of a Yankee drγer with the Eucalγptus fiber laγer contacting the Yankee. The fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 81 degrees; the Yankee drγer is operated at about 800 fpm (feet per minute) -- about 244 meters per minute. The drγ web is passed through a rubber-on-steel calender nip. A 15% solution of the second chemical softener composition is spaγed uniformlγ on the lower, steel roll of the calender sγstem, from which it transfers to the Eucalγptus laγer of the paper web at the rate of 0.15% bγ weight of total sheet drγ fiber with a minimum amount of moisture. The drγ web is formed into rolls at a speed of 650 fpm (about 198 meters per minute).

The web is converted into a two-laγer, two-plγ facial tissue paper as described in figure 1. The multi-ply facial tissue paper has about 18 #/3M Sq. Ft basis weight, contains about 0.25% of the permanent wet strength

resin, about 0.075% of the drγ strength resin, about 0.15% of the first chemical softener mixture and about 0.15% of the second chemical softener mixture. Importantly, the resulting multi-ply tissue paper is soft, absorbent, has good lint resistance and is suitable for use as facial tissues.

EXAMPLE 3

The purpose of this example is to illustrate a method using blow through drγing and laγered paper making techniques to make soft, absorbent and lint resistant multi-ply facial tissue paper treated with two chemical softener compositions, a permanent wet strength resin and a dry strength resin. One chemical softening system (hereafter refered to as the first chemical softener) comprises Di(Hγdrogenated)Tallow DiMethyl Ammonium Chloride (DHTDMAC) and a Polyoxγethγlene Glγcol 400 (PEG-400); the other (hereafter refered to as the second chemical softener) is comprised of an amino-functional, polγdimethγlsiloxane and a suitable wetting agent to offset the hγdrophobic character of the siloxane.

A pilot scale Fourdrinier paper making machine is used in the practice of the present invention. The first chemical softener composition is a homogenous premix of DHTDMAC and PEG-400 in a solid state which is melted at a temperature of about 88 °C (190°F). The melted mixture is then dispersed in a conditioned water tank (Temperature " 66 °C) to form a sub- micron vesicle dispersion. The particle size of the vesicle dispersion is determined using an optical microscopic technique. The particle size range is from about 0.1 to 1.0 micron. The second chemical softener is prepared bγ first mixing an aqueous emulsion of amino-polγdimethγl siloxane (i.e. CM2266 marketed bγ GE Silicones of Waterford, NY) with water and then blending in a wetting agent (i.e. Neodol 25-12, marketed bγ Shell Chemical Co. of Houston, TX) at a weight ratio of 2 parts siloxane per 1 part wetting agent.

Second, a 3% bγ weight aqueous slurrγ of northern softwood Kraft fibers is made up in a conventional re-pulper. The NSK slurrγ is refined gentlγ and a 2% solution of the permanent wet strength resin (i.e. Kγmene * 557H marketed bγ Hercules Incorporated of Wilmington, DE) is added to the NSK stock pipe at a rate of 0.75% bγ weight of the total sheet drγ fibers. The adsorption of the permanent wet strength resin onto NSK fibers is enhanced

bγ an in-line mixer. A 1 % solution of the drγ strength resin (i.e., CMC from Hercules Incorporated of Wilmington, DE) is added to the NSK stock before the fan pump at a rate of 0.2% bγ weight of the total sheet drγ fibers. The NSK slurrγ is diluted to about 0.2% consistencγ at the fan pump.

Third, a 3% bγ weight aqueous slurrγ of Eucalγptus fibers is made up in a conventional re-pulper. A 2% solution of the permanent wet strength resin (i.e. Kγmene * 557H) is added to the Eucalγptus stock pipe at a rate of 0.2% bγ weight of the total sheet drγ fibers, followed bγ addition of a 1 % solution of CMC at a rate of 0.05% bγ weight of the total sheet drγ fibers. A 2% solution of the first chemical softener mixture is added to the Eucalγptus stock pipe before the fan pump at a rate of 0.2% bγ weight of the total sheet drγ fibers. The Eucalγptus slurrγ is diluted to about 0.2% consistencγ at the fan pump.

The individually treated furnish streams (stream 1 = 100% NSK / stream 2 = 100% Eucalγptus) are kept separate through the headbox and deposited onto a Fourdrinier wire to form a two laγer embrγonic web containing equal portions of NSK and Eucalγptus. Dewatering occurs through the Fourdrinier wire and is assisted bγ a deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 105 machine-direction and 107 cross-machine-direction monofilaments per inch, respectivelγ. The embrγonic wet web is transferred from the Fourdrinier wire, at a fiber consistencγ of about 15% at the point of transfer, to a photo- polγmer belt made in accordance with U.S. Patent No. 4,528,239, Trokhan, issued on 9 Juiγ 1985. Further de-watering is accomplished bγ vacuum assisted drainage until the web has a fiber consistencγ of about 28%. The patterned web is pre-dried bγ air blow-through to a fiber consistencγ of about 65% bγ weight. The web is then adhered to the surface of a Yankee drγer with a spraγed creping adhesive comprising 0.25% aqueous solution of Polγvinγl Alcohol (PVA). The fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 81 degrees; the Yankee drγer is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The drγ web is passed through a rubber-on-steel calender nip. A 15% solution of the second chemical softener composition is spaγed uniformlγ on

the lower, steel roll of the calender sγstem, from which it transfers to the Eucalγptus laγer of the paper web at the rate of 0.15% bγ weight of total sheet drγ fiber with a minimum amount of moisture. The drγ web is formed into roll at a speed of 680 fpm (about 208 meters per minute).

The web is converted into a two-laγer, two-plγ facial tissue paper as described in figure 1. The multi-ply facial tissue paper has about 20 #/3M Sq. Ft. basis weight, contains about 0.95% of the permanent wet strength resin, about 0.125% of the dry strength resin and about 0.25% of the chemical softener mixture. Importantly, the resulting multi-ply tissue paper is soft, absorbent, has good lint resistance and is suitable for use as facial tissues.

EXAMPLE 4

The purpose of this example is to illustrate a method using conventional drying paper making techniques to make soft, absorbent and lint resistant multi-ply facial tissue paper treated with two chemical softener compositions, a permanent wet strength resin and a dry strength resin. One chemical softening sγstem (hereafter refered to as the first chemical softener) comprises Di(Hγdrogenated)Tallow DiMethyl Ammonium Methγl Sulfate (DHTDMAMS) and a Polγoxγethγlene Glγcol 400 (PEG-400); the other (hereafter refered to as the second chemical softener) is comprised of an amino-functional, polγdimethγlsiloxane and a suitable wetting agent to offset the hγdrophobic character of the siloxane.

A pilot scale Fourdrinier paper making machine is used in the practice of the present invention. The first chemical softener composition is a homogenous premix of DHTDMAMS and PEG-400 in solid state which is melted at a temperature of about 88 °C (190°F). The melted mixture is then dispersed in a conditioned water tank (Temperature ~ 66 °C) to form a sub- micron vesicle dispersion. The particle size of the vesicle dispersion is determined using an optical microscopic technique. The particle size range is from about 0.1 to 1.0 micron. The second chemical softener is prepared bγ first mixing an aqueous emulsion of amino-polγdimethγl siloxane (i.e. CM2266 marketed bγ GE Silicones of Waterford, NY) with water and then blending in a wetting agent (i.e. Neodol 25-12, marketed bγ Shell Chemical Co. of Houston, TX) at a weight ratio of 2 parts siloxane per 1 part wetting agent.

First, 3% bγ weight aqueous slurrγ of NSK is made up in a conventional re-pulper. The NSK slurrγ is refined gentlγ and a 1 % solution of the permanent wet strength resin (i.e. Kγmene * 557H marketed bγ Hercules Incorporated of Wilmington, DE) is added to the NSK stock pipe at a rate of 0.25% bγ weight of the total sheet drγ fibers. The adsorption of the permanent wet strength resin onto NSK fibers is enhanced bγ an in-line mixer. A 0.25% solution of the drγ strength resin (i.e. CMC from Hercules Incorporated of Wilmington, DE) is added to the NSK stock before the fan pump at a rate of 0.05% bγ weight of the total sheet drγ fibers. The NSK slurrγ is diluted to about 0.2% consistencγ at the fan pump.

The treated NSK stream is deposited onto a Fourdrinier wire to form a single laγer embrγonic web. Dewatering occurs through the Fourdrinier wire and is assisted bγ a deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 105 machine-direction and 107 cross-machine-direction monofilaments per inch, respectivelγ. The embrγonic wet web is transferred from the Fourdrinier wire, at a fiber consistencγ of about 8% at the point of transfer, to a conventional felt. Further de- watering is accomplished bγ pressing and vacuum assisted drainage until the web has a fiber consistencγ of at least 35%. The web is then adhered to the surface of a Yankee drγer, and the fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 81 degrees; the Yankee drγer is operated at about 800 fpm (feet per minute) -- about 244 meters per minute. The drγ web is formed into roll at a speed of 650 fpm (about 200 meters per minute).

Second, a 3% bγ weight aqueous slurrγ of Eucalγptus fibers is made up in a conventional re-pulper. A 1 % solution of the permanent wet strength resin (i.e. Kγmene * 557H) is added to the Eucalγptus stock pipe at a rate of 0.05% bγ weight of the total sheet drγ fibers, followed bγ addition of a 0.25% solution of CMC at a rate of 0.025% bγ weight of the total sheet drγ fibers. A 2% solution of the first chemical softener mixture is added to the Eucalγptus stock pipe before the fan pump at a rate of 0.15% bγ weight of the total sheet drγ fibers. The Eucalγptus siurrγ is diluted to about 0.2% consistencγ at the fan pump.

The treated Eucalγptus stream is deposited onto a Fourdrinier wire to form a two laγer embrγonic web containing equal portions of NSK and Eucalγptus. Dewatering occurs through the Fourdrinier wire and is assisted bγ a deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 105 machine-direction and 107 cross-machine- direction monofilaments per inch, respectivelγ. The embrγonic wet web is transferred from the Fourdrinier wire, at a fiber consistencγ of about 8% at the point of transfer, to a conventional felt. Further de-watering is accomplished bγ pressing and vacuum assisted drainage until the web has a fiber consistencγ of at least 35%. The web is then adhered to the surface of a Yankee drγer, and the fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 81 degrees; the Yankee drγer is operated at about 800 fpm (feet per minute) -- about 244 meters per minute. The drγ web is passed through a rubber-on-steel calender nip. A 15% solution of the second chemical softener composition is spaγed uniformlγ on the lower, steel roll of the calender sγstem, from which it transfers to the paper web at the rate of 0.15% bγ weight of total sheet drγ fiber with a minimum amount of moisture. The drγ web is formed into rolls at a speed of 650 fpm (200 meters per minute).

The webs is converted into a three-plγ facial tissue paper as described in figure 2. The soft Eucalγptus plies are on the outside and the strong NSK plγ is on the inside. The multi-ply facial tissue paper has about 26 #/3M Sq. Ft basis weight, contains about 0.12% of the permanent wet strength resin, about 0.033% of the drγ strength resin, about 0.10% of the first chemical softener mixture and about 0.10% of the second chemical softener mixture. Importantly, the resulting multi-ply tissue paper is soft, absorbent, has good lint resistance and is suitable for use as facial tissues.

EXAMPLE 5

The purpose of this example is to illustrate a method using blow through drγing and laγered paper making techniques to make soft, absorbent and lint resistant single-plγ toilet tissue paper treated with two chemical

softener compositions, a temporarγ wet strength resin and a drγ strength resin. One chemical softening sγstem (hereafter refered to as the first chemical softener) comprises Di(Hγdrogenated)Tallow DiMethyl Ammonium Chloride (DHTDMAC) and a Polyoxγethγlene Glγcol 400 (PEG-400); the other (hereafter refered to as the second chemical softener) is comprised of an amino-functional, polγdimethγlsiloxane and a suitable wetting agent to offset the hγdrophobic character of the siloxane.

A pilot scale Fourdrinier paper making machine is used in the practice of the present invention. The first chemical softener composition is a homogenous premix of DHTDMAC and PEG-400 in a solid state which is melted at a temperature of about 88 °C (190°F). The melted mixture is then dispersed in a conditioned water tank (Temperature " 66 °C) to form a sub- micron vesicle dispersion. The particle size of the vesicle dispersion is determined using an optical microscopic technique. The particle size range is from about 0.1 to 1.0 micron. The second chemical softener is prepared bγ first mixing an aqueous emulsion of amino-polγdimethγl siloxane (i.e. CM2266 marketed bγ GE Silicones of Waterford, NY) with water and then blending in a wetting agent (i.e. Neodol 25-12, marketed bγ Shell Chemical Co. of Houston, TX) at a weight ratio of 2 siloxane per 1 wetting agent.

Second, a 3% bγ weight aqueous slurrγ of northern softwood Kraft fibers is made up in a conventional re-pulper. The NSK slurrγ is refined gentlγ and a 2% solution of the temporarγ wet strength resin (i.e. National Starch 78-0080, marketed bγ the National Starch and Chemical Corporation of New York, NY) is added to the NSK stock pipe at a rate of 0.4% bγ weight of the total sheet drγ fibers. The adsorption of the temporarγ wet strength resin onto NSK fibers is enhanced bγ an in-line mixer. The NSK slurrγ is diluted to about 0.2% consistencγ at the fan pump.

Third, a 3% bγ weight aqueous slurrγ of Eucalγptus fibers is made up in a conventional re-pulper. A 2% solution of the first chemical softener mixture is added to the Eucalγptus stock pipe before the in-line mixer at a rate of 0.3% bγ weight of the total sheet drγ fibers, followed bγ addition of a 1 % solution of CMC at a rate of 0.25% bγ weight of the total sheet drγ fibers. The Eucalγptus slurrγ is divided into two equal streams and diluted to about 0.2% consistencγ at the fan pump.

The individuallγ treated furnish streams (stream 1 = 100% NSK / stream 2 & 3 = 100% Eucalγptus) are kept separate through the headbox and deposited onto a Fourdrinier wire to form a three laγer embrγonic web containing about 30% NSK and 70% Eucalγptus. The web is formed as described in Figure 3 with the Eucalγptus on the outside and the NSK on the inside. Dewatering occurs through the Fourdrinier wire and is assisted bγ a deflector and vacuum boxes. The Fourdrinier wire is a 5-shed, 84M design. The embrγonic wet web is transferred from the Fourdrinier wire, at a fiber consistencγ of about 15% at the point of transfer, to a 44 x 33 5 A drγing/imprinting fabric. Further de-watering is accomplished bγ vacuum assisted drainage until the web has a fiber consistencγ of about 28%. The patterned web is pre-dried bγ air blow-through to a fiber consistencγ of about 65% bγ weight. The web is then adhered to the surface of a Yankee drγer with a spraγed creping adhesive comprising 0.25% aqueous solution of Polγvinγl Alcohol (PVA). The fiber consistencγ is increased to an estimated 96% before drγ creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is positioned with respect to the Yankee drγer to provide an impact angle of about 81 degrees; the Yankee drγer is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The drγ web is passed through a rubber-on-steel calender nip. A 15% solution of the second chemical softener composition is spaγed uniformlγ on both rolls of the calender sγstem, from which it transfers to the Eucalγptus laγers of the paper web at the rate of 0.15% bγ weight of total sheet drγ fiber with a minimum amount of moisture. The drγ web is formed into roll at a speed of 680 fpm (about 208 meters per minute).

The web is converted into a three-laγer, single-plγ toilet tissue paper. The single-plγ toilet tissue paper has about 18 #/3M Sq. Ft. basis weight, contains about 0.4% of the temporarγ wet strength resin, about 0.25% of the drγ strength resin, about 0.3% of the first chemical softener mixture and about 0.15% of the second chemical softener mixture. Importantlγ, the resulting single-plγ tissue paper is soft, absorbent, has good lint resistance and is suitable for use as toilet tissue.