FIELD OF THE INVENTION

[0001] This disclosure relates to spandex fiber comprising ionic liquids and fabrics and garments made from the spandex fiber. The spandex fiber exhibits antistatic properties and reduces garment cling.

BACKGROUND OF THE INVENTION

[0002] Antistatic agents are used to dissipate electrostatic or static charge. Electrostatic charge buildup is responsible for a variety of problems in the processing and the use of many industrial products and materials. Electrostatic charging can cause materials to stick together or to repel one another. In addition, static charge buildup can cause objects to attract dirt and dust that can lead to fabrication or soiling problems and can impair product performance. Sudden electrostatic discharges from insulating objects can also be a serious problem. When flammable materials are present, a static electric discharge can serve as an ignition source, resulting in fires and/or explosions.

[0003] Electrostatic charge is a particular problem in the electronics industry, because modern electronic devices are extremely susceptible to permanent damage by electrostatic discharges. The buildup of electrostatic charge on insulating objects is especially common and problematic under conditions of low humidity and when liquids or solids move in contact with one another (tribocharging).

[0004] Static charge build-up can be controlled by increasing the electrical conductivity of a material. This can be accomplished by increasing ionic or electronic conductivity. The most common means of controlling static accumulation today is by increasing electrical conductivity through moisture adsorption. This is commonly achieved by adding moisture to the surrounding air (humidification) or by the use of hygroscopic antistatic agents, which are generally referred to as humectants because they rely on the adsorption of atmospheric moisture for their effectiveness. Most antistatic agents operate by dissipating static charge as it builds up; thus, static decay rate and surface conductivity are common measures of the effectiveness of antistatic agents. Antistatic agents can be applied to the surface (external antistatic agent) or incorporated into the bulk (internal antistatic agent) of the otherwise insulating material. Internal antistatic agents are commonly employed in polymers such as plastics. [0005] Generally, internal antistatic agents fall into one of the following classes: (I) ones that are mixed directly into a molten polymer during melt processing; (2) ones that are mixed into a polymer solution, coated, and dried, or (3) ones that dissolve into a monomer (with or without a solvent) that is subsequently polymerized.

[0006] Yams prepared from elastic polyurethane (PU) fibers comprising long chain synthetic polymers, a large portion of which are synthesized from PUs based on polyethers, polyesters and and/or polycarbonates are used in the production of sheet goods and woven textiles or substances which are suitable for garments, hosiery and sports clothing such as, but in no way limited to swimwear and bathing trunks. Knitting and weaving are forms of processing PU fibers.

[0007] One problem that can occur during processing of knitted and woven fabrics is the electrostatic charging of the fiber materials. In some cases, this can result in sparks flying due to intense electric charge phenomena. Thus, electrostatic charging can cause unwanted reduction in processing speed and costly installation of spray bars in the processing machines to dissipate.

[0008] There is a need for other means to render elastic PU fibers antistatic.

[0009] U.S. Patent 6,329,452 discloses adding dialkyl sulphosuccinate to elastic PU compositions and or by depositing this substance in a suitable form as an external preparation on elastic fibers for antistatic effect.

[00010] U.S. Patent 6,849,676 discloses application of salts of sulfonates having Cs-3o hydrocarbon chain, sulfates having Cs-3o hydrocarbon chain and phosphates having Cs-3o hydrocarbon chain as antistatic agents in production of antistatic PU elastic fiber.

[00011] U.S. Patent 8,715,799 discloses antistatic, thermoplastic PU comprising ethylmethylimidazole ethyl sulfate for shoe sector applications, elastomer rollers, manufacturing of electronically sensitive components and in pneumatic conveying of solids. [00012] U.S. Patent 8,993,660 discloses use of an antistatic composition comprising a polar thermoplastic polymer and an ionic liquid as an antistatic additive for non-polar thermo-plastic or elastomeric polymers.

[00013] U.S. Patent 9,012,590 discloses electrostatic dissipative thermoplastic PU compositions made by reacting at least one polyester polyol intermediate with at least one diisocyanate and at least one chain extender.

[00014] Published U.S. Patent Application No. 2015/0057388 discloses an antistatic PU with an ionic liquid as the antistatic additive. [00015] Published U.S. Patent Application No. 2017/0355805 discloses an ionic diol represented by formula wherein R ¹ represents an alkyl group having from 6 to 18 carbon atoms; R ² and R ³ independently represent alkyl groups having from 1 to 4 carbon atoms; R ⁴ represents an alkylene group having from 2 to 8 carbon atoms; and R ⁵ represents an alkylene group having from 1 to 8 carbon atoms in production of antistatic PUs.

[00016] However, use of small organic molecules like ionic liquids (see e.g. U.S. Patent 8,715,799, U.S. Patent 8,993,660, and published U.S. Patent Application No.

2015/0057388), ionic diol (see e.g. Published U.S. Patent Application No, 2017/0355805A1), dialkyl sulphosuccinate (see e.g. U.S. Patent 6,329,452B1), sulfonates/sulfate/phosphate of C8-30 chain (see e.g. U.S. Patent 6,849,676B1), and tri-n-butylmethylammonium bis- (trifluoromethanesulfonyl)imide (see e.g. U.S. Patent 9,012,590) as antistatic additives is based primarily on cation/anion small organic compounds which are water soluble and have poor interaction with PUs. Thus, these antistatic additives are gradually wiped off from surfaces by moisture and/or water after long term usage. Further, the small organic molecules are generally used as additives to a polyurethane matrix which is molded into parts such as shoes, belts, and rollers. In general, molded articles are not exposed to textile scouring and dyeing processes which can extract the small molecule additives. Therefore, durability of antistatic fiber is not a main concern in these applications.

[00017] U.S. Patent 6,403,682 discloses spandex having improved heat-set efficiency, obtained by incorporating certain quaternary amine additives into the spinning solution. No anti-static properties of the quaternary amine additives are di closed.

[00018] There is a need for functional antistatic additives for spandex fibers which resist removal by aqueous high-temperature scouring, dyeing, and finishing steps.

SUMMARY OF THE INVENTION

[00019] An aspect of the present invention relates to an antistatic spandex comprising spandex and an ionic liquid.

[00020] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises an imidazolinium alkyl sulfate having formula I wherein R1 represents alkyl or alkenyl groups with 6 to 22 carbons,

R2 represents -CHs or -CH2CH3 groups,

R3 represents -CH2CH2OH or -CH2CH2NH2 groups, and

R4 represents -CH3 or -CH2CH3 groups.

[00021] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises IH-Imidazolium, l-ethyl-2-(2-heptadecen-l-yl)-4,5-dihydro-3-(2-hydroxyethyl) -, ethyl sulfate (1 : 1).

[00022] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises a fatty acids reaction product with 2-((2-aminoethyl)amino)ethanol, or diethylenetriamine, dimethyl or diethyl sulfate quaternized.

[00023] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises a fatty acids, tail-oil, reaction product with 2-((2-aminoethyl)amino)ethanol, di-Et sulfate-quatemized.

[00024] In addition to its antistatic characteristics, spandex comprising the ionic liquid in accordance with this disclosure may exhibit enhanced coloration as compared to spandex without the ionic liquid and/or reduced cling as compared to spandex without the ionic liquid. [00025] Another aspect of the present invention relates to an article of manufacture, at least a portion of which comprises this antistatic spandex. Nonlimiting examples of such articles include fabric or garments.

[00026] Another aspect of the present invention relates to a spandex additive comprising an imidazolinium alkyl sulfate having formula I

[00027] wherein R1 represents alkyl or alkenyl groups with 6 to 22 carbons,

R2 represents -CHs or -CH2CH3 groups,

R3 represents -CH2CH2OH or -CH2CH2NH2 groups, and

R4 represents -CH3 or -CH2CH3 groups;

IH-Imidazolium, l-ethyl-2-(2-heptadecen-l-yl)-4,5-dihydro-3-(2 -hydroxyethyl)-, ethyl sulfate (1 : 1); or a fatty acids reaction product with 2-((2-aminoethyl)amino)ethanol, or diethylenetriamine, dimethyl or diethyl sulfate quaternized; or a fatty acids, tail-oil, reaction product with 2-((2-aminoethyl)amino)ethanol, di-Et sulfate-quatemized. Addition of this additive to spandex increases dyeability of the spandex with acid dyes.

[00028] Yet another aspect of the present invention relates to a method for producing antistatic spandex. The method comprises adding to spandex an ionic liquid.

[00029] In one nonlimiting embodiment, the ionic liquid comprises an imidazolinium alkyl sulfate having formula I formula II

[00030] wherein R1 represents alkyl or alkenyl groups with 6 to 22 carbons,

R2 represents -CPF, or -CH2CH3 groups,

R3 represents -CH2CH2OH or -CH2CH2NH2 groups, and

R4 represents -CH3 or -CH2CH3 groups.

[00031] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises IH-Imidazolium, l-ethyl-2-(2-heptadecen-l-yl)-4,5-dihydro-3-(2-hydroxyethyl) -, ethyl sulfate (1 : 1).

[00032] In another nonlimiting embodiment, the ionic liquid comprises a fatty acids reaction product with 2-((2-aminoethyl)amino)ethanol, or di ethylenetri amine, dimethyl or diethyl sulfate quatemized.

[00033] In another nonlimiting embodiment, the ionic liquid comprises a fatty acids, tail-oil, reaction product with 2-((2-aminoethyl)amino)ethanol, di-Et sulfate-quaternized.

[00034] Spandex produced in accordance with this method may also exhibit enhanced coloration as compared to spandex without the ionic liquid and/or reduced cling as compared to spandex without the ionic liquid.

BRIEF DESCRIPTION OF THE FIGURES

[00035] FIGs. 1 A through ID show two traditional choices for incorporating spandex into garments such as hosiery including every course style (ECPH) as depicted in FIG. 1 A and 1C and alternate course style (ACPH) as depicted in FIG. IB and ID.

DETAILED DESCRIPTION OF THE INVENTION

[00036] The present invention relates to antistatic spandex as well as spandex additives, methods of production of the antistatic spandex and articles of manufacture, at least a portion of which comprise the antistatic spandex.

[00037] The antistatic spandex of the present invention comprises segmented polyether-based polyurethaneurea, also routinely referred to as spandex.

[00038] The antistatic spandex of the present invention further comprises an ionic liquid added to the spandex. [00039] In one nonlimiting embodiment, the ionic liquid comprises an imidazolinium alkyl sulfate having formula I

[00040] wherein R1 represents alkyl or alkenyl groups with 6 to 22 carbons,

R2 represents -CH or -CH2CH3 groups,

R3 represents -CH2CH2OH or -CH2CH2NH2 groups, and

R4 represents -CH3 or -CH2CH3 groups.

[00041] In one nonlimiting embodiment, the ionic liquid of the antistatic spandex comprises IH-Imidazolium, l-ethyl-2-(2-heptadecen-l-yl)-4,5-dihydro-3-(2-hydroxyethyl) -, ethyl sulfate (1 : 1).

[00042] In one nonlimiting embodiment, the ionic liquid comprises a fatty acids reaction product with 2-((2-aminoethyl)amino)ethanol, or di ethylenetri amine, dimethyl or diethyl sulfate quatemized.

[00043] In one nonlimiting embodiment, the ionic liquid comprises a fatty acids, tailoil, reaction product with 2-((2-aminoethyl)amino)ethanol, di-Et sulfate-quatemized, also referred to herein as INC.

[00044] In one nonlimiting embodiment, the ionic liquid is added at 0.3-10% by weight of the spandex. In one nonlimiting embodiment, the ionic liquid is added at 0.3-3% by weight of the spandex.

[00045] By the phrase “weight of spandex”, it is meant the final weight of spandex including all additives.

[00046] Nonlimiting examples of ionic liquids useful in the antistatic spandex of the present invention include a mixture of amide and imidazoline, quaternized by di-Et sulfate, also referred to as INC 2470 (hereinafter referred to as INC), COLA® SOLV IES: Isostearyl Ethylimidazolinium Ethosulfate, CAS # 67633-57-2 and COLA® SOLV OES: Oleyl Ethylimidazolinium Ethosulfate (hereinafter referred to as OES), CAS # 68039-12-3 available from Colonial Chemical Company.

[00047] Also provided by the present invention are methods for producing antistatic spandex by adding one or more of these ionic liquids to the spandex. Ionic liquids can be simply mixed into the spandex solution at room temperature. In some nonlimiting embodiment, the ionic liquid is blended with other typical spandex additive such as, but not limited to, antioxidants, antacids, delusterants or/or lubricants. In one nonlimiting embodiment, the ionic liquid is added at 0.3-3% by weight of the spandex.

[00048] Without being bound to any particular theory, it is believed that the imidazolinium moiety in this ionic liquid additive contributes to good antistatic property with the long aliphatic chain helping it migrate to the fiber surface, thus providing for good durability during aqueous textile process. Further, the antistatic property of spandex fiber of the present invention containing an ionic liquid such as INC eliminates the building up of static charges during the fabric/garment process.

[00049] The antistatic spandex produced in accordance with the present invention exhibits excellent antistatic property, durability and commercial adaptability. Additional benefits, as demonstrated herein include enhanced coloration as compared to spandex without the ionic liquid and reduced cling as compared to spandex without the ionic liquid.

[00050] Also provided by the present invention is a spandex additive comprising an imidazolinium alkyl sulfate having formula I

[00051] wherein R1 represents alkyl or alkenyl groups with 6 to 22 carbons,

R2 represents -CHa or -CH2CH3 groups, R3 represents -CH2CH2OH or -CH2CH2NH2 groups, and

R4 represents -CH3 or -CH2CH3 groups;

IH-Imidazolium, 1 -ethyl -2-(2-heptadecen-l-yl)-4, 5 -dihydro-3 -(2-hydroxy ethyl)-, ethyl sulfate (1 : 1); or a fatty acids reaction product with 2-((2-aminoethyl)amino)ethanol, or diethylenetriamine, dimethyl or diethyl sulfate quaternized; or a fatty acids, tail-oil, reaction product with 2-((2-aminoethyl)amino)ethanol, di-Et sulfate-quatemized.

[00052] The inventors herein have found that addition of said spandex additive to spandex increases dyeability of spandex with acid dyes.

[00053] Antistatic spandex of the present invention can be used in any application or article of manufacture in which spandex is routinely used.

[00054] In one nonlimiting embodiment, the antistatic spandex is used in a fabric.

Fabrics comprising the antistatic spandex may have a spandex content of about 0.5 weight percent (wt. %) to about 40 wt. %, based on weight of the fabric. For example, circular knits comprising spandex may contain from about 2 wt. % to about 25 wt. % spandex, legwear comprising spandex may contain from about 1 wt. % to about 40 wt. % spandex.

[00055] The spandex or the fabric comprising it may be dyed and printed by customary dyeing and printing procedures, such as from an aqueous dye liquor by the exhaust method at temperatures between 60° C. and 100° C. Conventional methods may be followed when using an acid dye. For example, in an exhaust dyeing method, the fabric can be introduced into an aqueous dye bath kept in agitation having a pH of between 3.5 and 6 which is then heated steadily from a temperature of approximately 20° C. to a temperature about 98° C. for 40 minutes. The dye bath and fabric are then held at temperature for another 40 minutes before cooling. Unfixed dye is then rinsed from the fabric.

[00056] Additional examples of articles of manufacture, at least a portion of which comprise the antistatic spandex include, but are in no way limited to, sheet goods and knitted and woven textiles or substances which are suitable for garments, hosiery and sports clothing such as, but in no way limited to swimwear and bathing trunks. The antistatic spandex is particularly useful in knitting and weaving processes where electrostatic charge can be problematic.

[00057] The antistatic spandex of the present invention is particularly useful in hosiery. Two traditional choices for incorporating spandex of the present invention into garments such as hosiery include every course style (ECPH) as depicted in FIG. 1 A and 1C and alternate course style (ACPH) as depicted in FIG. IB and ID. The spandex fiber may be covered with, for example, polyamide, or may be bare, and is knitted in every course as depicted in FIG. 1 A and 1C or alternate courses as depicted in FIG. IB and ID. Garments such as every course panty hose (ECPH) comprise balanced stitches and normally provide for a higher quality garment.

[00058] Articles of manufacture in accordance with the present invention may be comprised of at least a portion of the knit structures described herein. Nonlimiting examples of these articles include clothing such as, but not limited to, pantyhose, stockings, knee highs, ankle highs, stay ups, leggings and socks. All standard garment processing steps are understood to be applicable to the fabric of this invention, (e.g. scour, dyeing, heat setting or boarding, application of softeners).

[00059] All patents, patent applications, test procedures, priority documents, articles, publications, manuals, and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.

[00060] The following Examples demonstrate the present invention and its capability for use. The invention is capable of other and different embodiments, and its several details are capable of modifications and/or substitution in various apparent respects, without departing from the spirit and scope of the present invention. Accordingly, the Examples are to be regarded as illustrative in nature and non-limiting.

EXAMPLES

Preparation of Spandex

[00061] A solution of segmented polyether-based polyurethaneurea elastomer was prepared by thoroughly mixing diphenylmethane diisocyanate (“MDI”) polytetramethylene glycol having a molecular weight of about 1800 in a molar (“capping”) ratio of 1.63. The mixture was maintained at a temperature of about 80-90° C. for about 90-100 minutes. The resulting “capped glycol”, comprising a mixture of isocyanate-terminated polyether glycol and unreacted diisocyanate, was cooled to 50° C. and mixed with DMAc to provide a solution containing about 45% solids. Then, with vigorous mixing, the capped glycol was reacted for 2-3 minutes at a temperature of about 75° C. with a DMAc solution containing a mixture of di ethylamine chain-terminator and 90/10 blend of ethylene diamine/2-methyl-l,5- diaminopentane chain-extender. The resulting polymer solution contained approximately 35% solids and had a viscosity of about 3,200 poises at 40° C. Surface resistivities of spandex film

[00062] The resistivities of the spandex/additives were measured on the following nonlimiting examples of spandex film by ASTM D-257. Results are depicted in Table 1.

Example 1

[00063] A film was casted from the spandex solution with drying in N2 chamber for 24 hours.

Example 2

[00064] The INC additive and spandex polymer was mixed in DMAC at room temperature with 1.0 wt% antistatic additive. A film was casted from the solution with drying in N2 chamber for 24 hours.

Example 3

[00065] The INC additive and spandex polymer was mixed in DMAC at room temperature with 2.0 wt% antistatic additive. A film was casted from the solution with drying in N2 chamber for 24 hours.

Table 1: Surface resistivity of spandex films at 56% RH

Surface resistivities of spandex yarn

[00066] The resistivities of the spandex/additives were measured on the following nonlimiting examples of spandex yarn. Results are depicted in Table 2.

[00067] For spinning, the following ingredients were thoroughly mixed and added to the polymer solution to provide the listed amounts of additive (expressed as weight percent based on the final weight of spandex):

(a) 1.2% of Irganox 245, a hindered phenolic antioxidant;

(b) 1.5% of natural blend of huntite and hydromagnesite;

(c) 0.4% of a silicone oil;

(d) 0.17% titanium dioxide as delusterant; and

(e) and where applicable, the amount of fatty acids, tail-oil, reaction products with 2- ((2-aminoethyl)amino)ethanol, di-Et sulfate-quaternized (INC), or IH-Imidazolium, 1 -ethyl - 2-(2-heptadecen-l-yl)-4, 5 -dihydro-3 -(2-hydroxy ethyl)-, ethyl sulfate (1 : 1) (OES). [00068] The spinning solutions were then conventionally dry-spun to form 22 decitex yarn without finish oil treatments. A thin layer of yam was peeled off the tube and the surface resistivity was measured by ASTM D-257.

Example 4

[00069] Spandex polymer solution was spun to form 22 dtex yam without INC or OES additive.

Example 5

[00070] The INC additive, spandex polymer, and other additives were mixed in DMAC at room temperature with 1.0 wt% antistatic additive. The polymer solution was spun to form 22 dtex yam with 1.0 wt% antistatic additive.

Example 6

[00071] The INC additive, spandex polymer, and other additives were mixed in DMAC at room temperature with 2.2 wt% antistatic additive. The polymer solution was spun to form 22 dtex yam with 2.2 wt% antistatic additive.

[00072] The spandex yams of Examples 4 through 7 were treated by scouring, dyeing and finishing aqueous textile process.

Scouring Process

[00073] In the scouring process, 8.0 grams of spandex yarn was pulled and placed into laundry bag. In a 1000 mL beaker, the yam was then added into -1000 mL solution of scouring agent Domoscour LFE-810 (Archroma U.S., Inc.) (0.5 g/L) and soda ash (0.5 g/L) with magnetic stirring. The temperature was raised to 80°C @3°C/min (~20min raised to 80°C) and held for 30 minutes. The yam was then rinsed with deionized DI water until clear.

Dyeing Process

[00074] In 1000 mL beaker, a 5% acetic acid stock solution was used to adjust pH to 4.5-5.0. 0.5g Dorolan Black (commercial from M. Dohmen GmbH) was then added to the solution and stirred until dissolved. Spandex yam in a laundry bag was then into the dye solution. The temperature was raise to 98 °C (close to boiling) at a rate of 2°C/min (increase to 98°C in about 35 min) and held at 98 °C for 30 min. The solution with spandex was then cooled to 70 °C and the dye solution was drained.

Finishing Process

[00075] Deionized water was added to a beaker and adjusted to a pH to 4.5-5.0 at room temp. 0.5g Domofix FN6(M. Dohmen USA, Inc.) fixing agent was added to the solution. The temperature was then raised to 75 °C with rate 2°C/min and held at 75 °C for 20 min followed by cooling to 50°C and draining of the solution. The spandex was then rinsed with deionized water until clear and air-dried.

Example 7

[00076] The spandex yam in example 4 was treated by scouring, dyeing and finishing process.

Example 8

[00077] The spandex yam in example 5 was treated by scouring, dyeing and finishing process.

Example 9

[00078] The spandex yam in example 6 was treated by scouring, dyeing and finishing process.

Table 2: Surface resistivity of spandex yarns at 33% RH

[00079] Example 5 and 6 with antistatic additives exhibited lower surface resistivity (better antistatic properties) than Example 4 without antistatic additives. Example 8 and 9 with antistatic additives exhibited lower surface resistivity (better antistatic properties) than Example 7 without antistatic additives after black dyed. Examples 5 and 6 without a dye exhibited better anti-static properties as compared to Examples 8 and 9 which were dyed black.

Example 10

[00080] The INC additive, spandex polymer, and other additives were mixed in DMAC at room temperature with 1.5 wt% antistatic additive. The polymer solution was spun to form 22 dtex yam with 1.5 wt% antistatic additive. Example 11

[00081] The OES additive, spandex polymer, and other additives were mixed in DMAC at room temperature with 1.5 wt% antistatic additive. The polymer solution was spun to form 22 dtex yam with 1.5 wt% antistatic additive.

Example 12

[00082] The spandex yam in example 10 was treated by scouring, dyeing and finishing process.

Example 13

[00083] The spandex yam in example 11 was treated by scouring, dyeing and finishing process.

Table 3: Surface resistivity of spandex yarns at 33% RH

Enhanced coloration of spandex fiber

[00084] Spandex (235 dtex), with and without the INC additive as disclosed in Examples 4 and 5 supra, herein referred to Examples 10 and 11 respectively, were knit in a tubular format with an alternating 100% polyamide section (to evaluate the color of polyamide only) with 100% spandex section (to evaluate the dye pick up of spandex only) and a spandex and polyimide knit together section representative of a commercial hosiery waist band. Polyamide was 44 dtex. This format was selected to evaluate the dye pick up from polyamide and spandex separately (first and second sections respectively) and together in a more commercial construction (third section). The final composition of the tube was approximately 80% polyamide and 20% spandex. The tube was then scoured at 80° C. with Ig/L of soda ash and detergent. The fabric was rinsed and then dyed through an exhaust dyeing method in a solution with 1.5g/L of acid donor and 3% black metal complex dye (CI 194) for 40 min. After dyeing, the fabric samples were fixed with 4% Sunlife TNF under acidic conditions. After drying, the fabric samples were analyzed by colorimeter for dye uptake under the competitive dye situation. Dyeability performance was determined from color shade lightness “L*” values with a colorimeter spectral analyzer. Results are reported in CIELAB units under D65 illuminant. Color depth, “L*” values, on the dyed spandex sections were compared to polyamide sections from the same dyebath and listed in Table 4.

Table 4: Lab color results for finished fabrics

[00085] Example 10 with no antistatic additive showed limited shade depth compared to polyamide “L*” value while Example 11 with 1% INC additive provides a low “L*” value (18.4) like polyamide. “AE*” value calculated with CIE74 formula is a metric to measure the color difference. The lower “AE*” value the higher is the color match between two substrates. Example 10 with no antistatic additive shows poor color match between spandex and polyamide with “AE*” of 22.2 while Example 11 with 1% INC additive provides a better color match with lower “AE*” value of 5.1. The better color match between the two fibers contributes to providing better invisibility of the spandex in the knit structure, a desirable property of spandex containing fabrics.

Consumer testing and garment cling

[00086] Fabrics were knit using a Lonati 400 needles, 4 inches diameter hosiery knitting machine to make the constructions using the standard four feed system. An elastified knitted garment was prepared by typical ECPH wherein all 4 feeds were 22 dtex monofil spandex of either Example 4, 5, or 6 supra knitted bare with flat PA6,6 33f20. Each fabric sample was knit at 450 rpm. The fabrics indicated as every course single jersey included a plain stitch. The fabrics were sewed into garments in the form of traditional pantyhose.

[00087] Each pantyhose was then dyed using standard industry protocols for nylon hosiery using acid dyes in black and beige/tan colors. The hosiery was boarded using a commercial Cortese boarding machine which accepts hosiery legs in clam-shell compression compartment and applies steam pressure for a selected dwell period. The black garments were further washed 5X in a normal residential laundering process to test efficacy after normal use. Garments were tested with synthetic light outerwear (polyester and acetate) and insulating footwear (rubber soles). Wearer noted the presence and degree of static cling between the knitted hosiery and synthetic outerwear (skirt or dress).

[00088] Similarly, an elastified knitted garment was prepared using ACPH wherein feed 1 and 3 were 22 dtex spandex of Example 4, 5, or 6 supra knitted bare with flat PA6,6 22f7 and feed 2 and 4 were PA only. Garment was dyed in medium skin tone shade for testing by a hosiery consumer panel.

[00089] Results of cling testing for these elastified knitted hosiery are depicted in Table 5.

Table 5: Garment wear tests for static control

Ranking

Noticeable and uncomfortable cling

* Minor cling with motion

+ No cling with motion