|1.||A method of treating a fibrous cellulosic textile mateπal which method compπses treating the textile with a treatment agent compπsmg one or more olιgomer(s) and/or polymer(s) of maleic anhydπde and/or maleic acid, and thereafter heating the treated textile to cure the treatment agent onto the fibres of the cellulosic textile .|
|2.||A method as claimed in claim 1 wherein the olιgomer(s) and/or polymer(s) of maleic anhydnde and/or maleic acid has a molecular weight of from 300 to 100000.|
|3.||A method as claimed in either claim 1 or claim 2 wherein the treatment agent is an aqueous solution of the one or more olιgomer(s) and/or polymer(s) of maleic anhydπde and or maleic acid at a concentration of from 0 1 to 30% of the solution A method as claimed in any one of claims 1 to 3 wherein the treatment agent includes at least one esteπfication catalyst 5 A method as claimed in claim 3 wherein the treatment agent solution includes from 0 1 to 30% by weight, of the at least one esteπfication catalyst. A method as claimed in any one of claims 1 to 5 wherein the treated textile mateπal is subsequently treated at a temperature of from 150 to 240°C to cure the treatment agent onto the textile mateπal. A cellulosic textile mateπal which cames residues of oligomenc and/or polymeπc maleic acid and/or anhydπde esteπfied to hydroxylic sites in the cellulose An aqueous solution containing at least one olιgomer(s) and/or polymer(s) of maleic anhydπde and/or maleic acid also containing at least one esteπfication catalyst A solution as claimed in claim 8 containing from 0 1 to 30% by weight of the at least one olιgomer(s) and/or polymer(s) of maleic anhydnde and/or maleic acid and from 0 1 to 30% by weight of the at least one estenfication catalyst.|
The present invention relates to a method of treating fabπcs or yarns to make them or fabπcs made from them more resistant to wπnkles and/or creases and in particular to such a method that does not use compounds deπved from formaldehyde or compounds that liberate formaldehyde on treatment of the fabπc and/or yam or on subsequent use. The invention relates to such a process for treating cellulosic fabπcs and/or yarns or blends containing such cellulosic mateπals.
Methods of treating fabπcs to impart wπnkle and/or shrinkage resistance to cotton fabπcs are known. Fabπcs or garments having cotton, upon such treatment retain their dimensions, smooth appearances and normal shapes while in use and also during machine wash or tumble dry processes. Commercially, such treatment of cellulosic mateπals is typically earned out by high speed, durable press finishing processes using formaldehyde or formaldehyde addition products, such as those with urea or cyclic urea, carbamate esters or with other amides. The treatment agents are applied to typically cotton textiles with an acid catalyst, and heated to induce crosslinking. These formaldehyde addition products are effective and cheap for such uses. Unfortunately, they have the serious disadvantage in that they can release formaldehyde during durable press finishing processes, storage of fabric, manufacture of garments and, even duπng the use of garments by the customer. Formaldehyde vapours are known eye-irritants and skin allergens. Accordingly, there has been a need for durable press finishing processes that do not employ formaldehyde or its addition products. Such conventional processes also have the disadvantage that they require Lewis acid catalysts and high temperature to ensure sufficient and rapid crosslinking of the cellulose. However, Lewis acids at high temperature can cause degradation of cellulose molecules and loss of strength in the finished fabπc.
A number of other approaches have been investigated, including formulations based on glyoxaldehyde, acetals, glyoxaldehyde amides, reactive silicones and polycarboxylic acids having more than two carboxylic acid groups. Thus. Gagliardi and Shipee, in Ameπcan Dyestuff Reporter 52, pp 300 to 303, (1963) describe the use of polycarboxylic acids with or without catalysts in treatments to impart wπnkle resistance to cotton fabπcs. However, although many of the hazards of formaldehyde processes can be avoided, they noted greater fabπc strength losses than with formaldehyde based agents.
Rowland et al in Textile Research Journal 37, 933-941 (1967) disclosed a treatment using polycarboxylic acids partially neutralized with sodium carbonate or tπethylamtne pπor to application to the fabπc. Good cross linking of cellulose was observed, but a gradual reduction of wπnkle resistance was notec -ifter repeated laundering cycles showing a lack of durability of the finish to alkaline solutions such as laundeππg detergents. Further, the cuπng time for fabπc finishing was too long to permit high speed, mill-scale production.
A later article by Rowland and Brannan, Textile Research Journal 38, 634-643 (1968), descπbed that cotton fabπcs treated as descπbed above were recurable and that creases durable to 5 laundering cycles could be made. US Patent 3526048 descπbes similar results neutralizing 1 to 50% of the carboxylic acid groups using an alkali metal hydroxide, carbonate, bicarbonate, acetate, phosphate or borate, prior to impregnating the fibrous cellulose with the aqueous polycarboxylic acid and heating to induce cross linking.
US Patent 4975209, to Welch et al. discloses cellulose crosslinking agents which are polycarboxylic acids including aliphatic, aiicyciic and aromatic acids which are reported as good crosslinking agents at elevated temperatures in the presence of acidic or weakly basic salts. The treated textiles show good wrinkle resistance and smooth drying properties durable to repeated laundeπng in alkaline detergents. A further US Patent 4820307 to Welch et al, also discloses particular types of polycarboxylic acids such as maleic. citπc and butanetetracarboxylic acids as cross linking agents in the presence of phosphorus containing catalysts.
US Patent 5042986 descπbes crosslinking cellulose using cyclic aliphatic polycarboxylic acids having two adjacent carboxyl groups in the trans-configuration. Canadian Patent 2097483 also descπbes esteπfication and crosslinking of cellulose in textiles using polycarboxylic acids having more than two carboxylic acids, at elevated temperatures with bone acid or a αeπvatrve as crosslinking catalyst.
Two polycarboxylic acids which have evoked industrial interest are 1,2,3,4-butanetetracarboxylic acid (BTCA) and citπc acid. BTCA is one of the most effective crease resist resins and has been marketed by Glo-Tex Inc. as Reactisol DP-4, but very expensive and difficult to synthesise (Reactisol DP-4, Glo-Tex Chemicals, Inc. P. O. Box 400, Roebuck, S. C. 29376).
We have found that despite the significant steps which have been made in avoiding the disadvantages of formaldehyde based crosslinking agents, much is still left desired. In particular, strength loss and the discoloration of fabπcs. especially upon ironing, remain problems.
The present invention is based on our discovery that oligomeπc and/or polymeπc compounds deπved from repeat units of maleic acid and/or anhydπde can be used as effective treatment agents for cellulosic materials to improve their crease resistance. We believe that these agents work by crosslinking cellulose molecules in the fabrics by forming ester bonds with hydroxyl groups in the cellulose molecules and for convenience we refer to this mechanism herein. However, the particular chemical mechanism is not itself critical to this invention.
Accordingly, this invention provides a method of treating a fibrous cellulosic textile mateπal, particularly to improve its crease resistance, which method compπses treating the textile with a treatment agent comprising one or more olιgomer(s) and/or polymer(s) of maleic anhydride and/or
maleic acid, and thereafter heating the treated textile to cure the treatment agent onto the fibres of the cellulosic textile.
The substrate that is treated in this invention is descπbed as a fibrous cellulosic textile mateπal. By this we mean that the substrate is cellulosic or contains, typically, from 30 to 100% fibres of cellulosic mateπal. Typical cellulosic fibre mateπals which can be included in fabπcs treated according to this inventions include cotton, flax, rayon, jute, hemp and ramie. The cellulosic mateπal can be a blend of fibres of cellulosic materials with non-cellulosic mateπals and in particular includes blends of cellulosic fibres, particularly cotton, with polyester, particularly polyethylene terephthalate polymer or related copolymers. The textile can be a woven (including knitted) or non-woven textile, but as crease resistance is particularly important in clothing, the textile will usually be a clothing textile mateπal.
The present invention includes a novel formaldehyde free method of treating , particularly for imparting wπnkle/crease resistance and smooth drying/shape retention properties to, cellulosic or cellulose containing textiles, particularly containing 30-100% cellulosic materials, which compπses treating the textile mateπal with one or more oligomeπc and/or polymeric maleic acid and/or anhydπde.
The abbreviation OMA used herein, refers to oligomers and/or polymers of maleic anhydride and/or acid. Generally, the oligomers and polymers used include 3 or more maleic acid and/or anhydride units per molecule. Typically the OMA used in the invention will have a molecular weight of from about 300 to 100000, particularly from about 300 to 15000 and more particularly 300 to 2000. The term oligomeπc maleic acid is sometimes used herein and this term includes oligomeπc and polymeπc maleic acid and/or anhydπde as set out above.
This invention includes a method of treating , particularly for imparting wπnkle/crease resistance and smooth drying/shape retention properties to. cellulosic or cellulosic containing textile mateπals which compπses treating the textile mateπal with an oligomer and/or polymer of maleic anhydride and/or acid, having 3 or more maleic anhydride or acid units.
More particularly, the process of the invention includes treating the cellulose or cellulose containing textile mateπals with oligomeπc and/or polymeπc maleic anhydπde and/or acid in the presence of at least one cuπng catalyst and then heat curing the treated textile to produce esteπfication and crosslinking of the cellulose with the oligomeπc and/or polymeπc maleic anhydnde and/or acid.
The invention also includes cloth treated by the method of the invention and in particular, a cellulosic textile material, which may be woven (including knotted) or non-woven, which carπes residues of o gomeπc and/or polymeric maleic acid and/or anhydπde esteπfied to hydroxylic sites in the cellulose.
More particularly, the method of the invention employs an aqueous solution containing about 0.1 to 30% by weight of oligomeπc/polymeπc maleic acid having average molecular weight from 300 to 100000, preferably from about 300 to about 15000 and more particularly from 300 to 2000. While not being bound to any theory, it is believed that the lower molecular weight oligomeπc and/or polymeπc maleic acids and/or anhydπdes of this invention work best because they can penetrate more easily into the yams of the fabric and. therefore, the lower molecular weight oligomeπc and polymeπc acids are preferred. This is most surpπsing since none of the pπor art which report the use of polycarboxylic acids point out. even in a remote way, that the oligomer and/or polymer of maleic acid and/or anhydnde will behave in such an advantageous fashion, in fact, no pπor art known to the applicants suggest the use of a polymer of a polycarboxylic acid as a crosslinking agent, leave alone an oligomer and/or polymer or mixtures therefrom of maleic acid and/or anhydride.
Accordingly, the present invention includes a method of treating a cellulosic or cellulose containing textile mateπal, particularly to produce improved fabπc mateπal having wnnkle/crease resistance and smooth drying properties, which method compπses treating the cellulosic textile mateπal with an aqueous solution containing at least one oligomer and/or polymer of maleic acid and/or anhydride having an average molecular weight in the range of from 300 to 100000 and one or more cuπng catalyst and heating the treated mateπal to cause esterification and crosslinking of said mateπal with said crosslinking agent to produce said improved fabπc mateπal.
In particular the oligomenc and/or polymeπc maleic acid and/or anhydπde includes repeat units:
' < - > - a n d / o r " ( ^ ~ ) "
O ^ Q ^ O M0 2 C C0 2 M
where each M is independently H, a metal, particularly an alkali metal, or ammonium; and the number of such repeat units in the oligomer and/or polymer averages from about 3 to about 1000 (corresponding to the aDove described molecular weight ranges).
The particular concentration of oligomenc maleic acid used in the treating solution will depend uoon the degree of cross linking desired and on the proportion of cellulosic fibres in fabπc being treated. Thus, any convenient concentration of the crosslinking agent may be selected depending upon the degree of crosslinking desired, the preferred range being from about 0.1 to 30% by weight more usually and desirably 0.5 to 20% by weight. The amount of OMA applied to the fabπc will typically be from 1 to 10%, particularly from about 2 to about 7%, by weight of OMA based on the dry fabπc weight.
The oligomers and polymers of maleic anhydπde and/or acid used in this invention can be synthesized by known methods, particularly by free radical polymeπsation starting with maleic acid and/or anhydπde, for example initiated by peroxides or other similar free radical initiators Methods of synthesis of the oligomers and polymers use dm this invention are descπbed, for example as 5 described in FR 1544728, US 4260724 DE 2405284 A, DE 2732628 A Makromol Chem , 53. 33, 55 35 (1962), Eur Polym J , 12 883 (1976) and 11 31 (1975), Makromol Chem , 124, 249 (1969), J Macromol Sci , Part A, 10, 1017 91976, US 3385834, GB 1073323, DE 2154510 A, US 3457240 and Handbook of polymer synthesis Part A, ed H R Kπcheldorf Marcel Dekker Inc , Chap 4 pp 223-310 (1992)
To achieve the best results, the treatment of the fabπc will usually be earned out in the presence of a cuπng catalyst. Accordingly, the treatment solution typically includes a suitable cuπng catalyst at a concentration usually of about 0 1 to 30% by weight Amounts outside this range can be used, but will usually be less desirable In particular, the catalyst is typically used at a level of from 5 to
15 20%, especially about 10 to about 15%, by weight on the weight of the solid resin used in the treatment of the fabnc The catalyst can be an esteπfication catalyst for example as is descπbed in more detail below
Typical catalysts are esteπfication catalysts Examples of suitable catalysts include mineral acids 0 such as hydrochloπc, sulphuπc, fluoroboπc, phosphoπc, phosphorous and hypophosphorus acids; organic acids such as glycolic. maleic, lactic, citπc, tartaπc and oxalic acids, metal, particularly alkali metal e.g sodium, potassium and lithium, salts of the above acids; metallic salts such as magnesium or zinc, chloπde, nitrate, sulphate, fluoroborate or fluorosilicate, ammonium chloπde or nitrate, aluminium chionde. zirconium oxychloπde, sodium and/or potassium bisulphite or 5 bisulphate. alkali metal haiides, sodium and/or or potassium phosphite and/or hypophosphite and/or dihydrogen phosphate, disodium or dipotassium hydrogenphosphate, alkali metal salts of poiyphosphoπc acids such as disodium and/or dipotassium acid pyrophosphate. tetra- sodium and/or potassium pyrophosphate, penta- sodium and/or potassium tπpolyphosphate, sodium and/or potassium hexametaphosphate and/or tπmetaphosphate or sodium tetrametaphosphate; 30 boron acids such as bone acid and their denvatives such as orthoboπc acid, alkali or alkaline earth metal salts of polyboπc acids or borate esters of the formula B(OR) 3 , where R is alkyl or aryl, amme hydrochloπdes, such as 2-amιno-2-methyl-propanol hydrochloπde and similar products The catalyst compounds can be used alone or in combination
35 The curing catalyst used is typically used in the treatment solution in a concentration of from 0 1 to 20% by weight The precise amount or concentration used will depend on the particular application and we expect that those skilled in the art will not have difficulty in choosing appropπate amounts and/or concentrations
The invention includes a method of treating a fibrous cellulosic textile mateπal to improve its crease resistance, which method compπses treating the textile with a treatment agent compπsing one or more olιgomer(s) and/or polymer(s) of maleic anhydπde and/or maleic acid and with an esteπfication catalyst, and thereafter heating the treated textile to cure the treatment agent onto the fibres of the cellulosic textile
The invention further includes a treatment solution which compπses an aqueous solution of at least in one olιgomer(s) and/or polymer(s) of maleic anhydπde and/or maleic acid, particularly at a concentration of from 0 1 to 30% by weight of the solution and at least one esteπfication catalyst. particularly at a concentration of from 0 1 to 30% by weight of the solution
The invention also includes textile materials treated by the method of the invention or treated using the treatment solution of the invention
The method is typically is earned out by first impregnating the cellulosic or cellulosic containing textile mateπals with the aqueous treating solution Excess liquid can be removed, for example by passing the treated mateπal through wringers and drying to remove the solvent Typically, the treated mateπal is then oven cured at an elevated temperature, for example from about 150 to 240°C for a peπod of from 5 seconds to 30 minutes, particularly 5 seconds to 5 minutes, to cause cellulose esteπfication and cross linking
The term formaldehyde free used in relation to a method herein means that the method does not release formaldehyde vapours duπng the treatment of textiles or fabπcs to improve their wπnkle/crease resistance, duπng manufacture of garments from finished fabπc. duπng retailing of the garments or apparel goods or use of such goods by consumers
The term "wrinkle or crease resistance" as used herein means that a treated fabπc is less likely to wπnkle/crease or has less wπnkles or crease after being worn or after a laundenng operation than it would have, were it not so treated, after a comparable operation
The term "shape retention/smooth drying" as used herein means that a pre-ironing of textile material fabπc or cloth treated according to the invention is less likely to wrinkle or lose its ironed shape after being worn than it would had it not been so treated
The following Examples illustrate the invention All parts and percentages are by weight unless otherwise stated
A An oligomer of maleic acid (5 Og), prepared by the literature method (free radical polymerisation in xylene as solvent using benzoyl peroxide aas initiator), sodium hypophosphite
(5.0 g), ALN-GM (a glyceryl monolaurate 23-ethoxylate surfactant) (1.0 g) and NP-10 (a nonyl phenol 10-ethoxylate surfactant) (100 mg) were dissolved in deiomsed water (69.0 g). Cotton cloths (10x10 inch; ca 25x25 cm) were dipped in this solution and passed through a wπnger to pick up 80% weight of the cloth of the treatment solution. This procedure was repeated twice for each sample and the treated samples stretched on a rack and dned in a forced air draft oven at 90°C for 5 minutes. The dry samples were heated to cure them in an air draft oven at 160°C for either 2 (sample 1a) or 3 (sample 1b) minutes as shown in Table 1. After this heat treatment, the specimens were washed in hot running water at 45 - 50°C for 30 minutes. The samples were then dried in an air forced draft oven for 10 minutes at 90°C and conditioned (65% RH; 22 - 24°C) for 24 hours. Wrinkle recovery angles (WRA) were than determined by ICI CAMG-26 method (equivalent to AATCC Test Method 66-1990 "Wrinkle Recovery of Fabπcs: Recovery Angle Method). This method is used for determining the wπnkle recovery angles of textiles. The wπnkle resistance of woven textiles is represented in terms of wπnkle recovery angles. The greater is the wπnkle recovery angles more is the wnnkle resistance of the fabπc. The results of this study are set out in Table 1 below.
Example 1 was repeated except that the treatment solution was made up using 7 g oligomeπc maleic acid and 7 g sodium hypophosphite. The samples obtained were 2a (cuπng at 160°C for 2 minutes) and 2b (cuπng at 160°C for 3 minutes). The results of testing as described below are included in Table 1. Control samples were made up using untreated cloth (C1) and cloth treated with a conventional formaldehyde based treatment agent based on dimethylol dihydroxyethyleneurea (DMDHEU) (C2).
The DMDHEU used in control C2 was Arkofix NC resin (from Hoechst) which contains 70% DMDHEU resin. The test fabπc was treated with 5% of the weight of fabric DMDHEU resin, in the presence of MgCI 2 (15% based on the weight of the DMDHEU resin). The resin was applied in a double dip. double nip procedure at a wet pick up of about 80%. After applying the resin solution. the fabric was dried and cured at 160°C for 2 minutes. The fabric was then washed with hot running water at 45 - 50°C for 30 minutes, dried in an air forced draft oven for 10 minutes at 90°C and then conditioned (65% RH; 22 - 24°C for 24 hours). Wrinkle/crease recovery angles were determined on the C1 and C2 samples by the method descπbed above and the results are included in Table 1 below.
The tear strength of treated and untreated fabπc was measured using a standard tester manufactured by Testing Machines, Inc. following the TMI method 83-10. The results are expressed as the percentage tear strength of treated cloth as compared with an untreated control. The results of tear testing are included in Table 1.
A compaπson in the Whiteness Index of fabric treated with oligomeπc/polymeπc maleic acid and DMDHEU was made before and after washing at 60°C for 12 minutes in a domestic laundry washer after adding detergent (1g.ϊ 1 in water) on a Milton Roy Colour Match Scan II. The reflectance in visible range from 400 to 700 nm was measured and the Whiteness Index CIE calculated. The test results on the samples of Examples 1 and 2 and C2 are included in Table 1.
1 percent concentration of treatment resin in solution.
2 percent concentration of catalyst in treatment solution.
Next Patent: A SCREEN HAVING INCLINED SLOTS FOR USE IN A CONTINUOUS DIGESTER