US3900618A - Process for reducing pilling tendencies of acrylic fibers and fiber products thereof - Google Patents

Abstract

Acrylic fibers, or products therefrom, are reduced in pilling tendencies when treated under specific conditions with an aqueous solution of an alkylsulfate salt and sodium carbonate.

Description

United States Patent Sasada Aug. 19, 1975 [54] PROCESS FOR ED IN FILLING 2,130,460 9/1938 Evans 6: a1. 19 66 TENDENCIES OF ACRYLIC FIBERS AND 5 :22; :32 i 3 32 6 6 omas e a FIBER PRODUCTS THEREOF 2,689,195 9 1954 Martone 117 65 [75] Inventor: Juichi Sasada, Okayama, Japan 2,998,296 8/1961 Hennemann... 18/1155 3,127,305 3 1964 Hirshfeld 161/64 1 Asslgneei Amman cyanamld Company, 3,152,919 10 1964 Biles et a1. 117/138.8 Stamford, Conn- 3,264,705 8/1966 Kovarik 28/76 [22] Filed: Dec. 13, 1973 FOREIGN PATENTS OR APPLICATIONS [21] Appl. N0.: 424,408 1,030,317 5/1966 United Kingdom I Primarv Examin'erP. E. Willis Jr. 52 US. Cl. 427/390 A A I J L 511 Im. c1. B44d l/06; D06m 13/26 gen [58] Field of Search 8/115.6; 19/66 R; 28/75 R,

28/74 H; 1l7/138.8 UA, 139.5 CF, 139.5 [57] ABSTRACT CQ; 252/8] 550 Acrylic fibers, qr products therefrom, are reduced in pilling tendencies when treated under specific c0ndi- [56] Refere e Cited tions with an aqueous solution of an alkylsulfate salt UNITED STATES PATENTS and Sodmm bw 2,012,610 s/1935 Lenher 28/1 181C1aims, No Drawings PROCESS FOR REDUCING PILLING TENDENCIES OF ACRYLIC FIBERS AND FIBER PRODUCTS THEREOF This invention relates to a process for reducing the tendency of acrylic fiber product to pill. More particularly, the present invention relates. to such a process where by treating the acrylic fiber with an aqueous solution containing an alkyl sulfate and sodium carbonate, the pilling tendencies of the fiber products are permanently reduced.

It is well known that acrylic fibers and products therefrom are popular for such uses as jerseys, sweaters, dress shirts, knitting yarns and the like because they possess outstanding properties such as vivid dyed colors, unusual bulk, and others not found in other synthetic fibers.

However, acrylic fibers, in spite of their great usefulness, are not free from deficiencies and processes by which these deficiencies can be overcome are urgently sought.

A particular deficiency of the acrylic fibers is their tendency to pill, i.e., to form a small rounded mass of fiber. Pilling lowers the aesthetic appeaarance of appearance fiber products and, therefore, there is a great need to provide a successful process for overcoming the pilling tendencies of acrylic fibers and products therefrom.

Pilling, however, is not a problem peculiar to acrylic fibers but is a deficiency common to products of most other synthetic fibers such as polyamide, polyester, etc. The formation of pills takes place on the surface of woven and knit fabrics by repeated friction of the fibers with themselves during normal wearing of the fiber products. Woven and knit fabrics of synthetic fibers appear to have a greater tendency to pill in use than do fabrics of natural or regenerated fibers such as cotton and rayon and a prolonged wearing period will impair the aesthetic appearance and wearing comfort of the fiber products. For these reasons, an urgent need in overcoming the pilling problem arises.

Pilling is also observed in the case of fiber products of natural and regenerated fibers. However, in the case of such fibers, because of their low strength, the pills generated will fall off the fiber product by simple mechanical friction during wearing or washing. As a result, there will be little accumulation of pills during the service use of the products of natural or regenerated fibers. On the other hand, because synthetic fibers, e.g., acrylic fibers, have much greater strength than natural or synthetic fibers, the rate at which pills form is greater than the rate at which they fall off fiber products. Accordingly, the pills formed remain semipermanently on the fabric surface without being removed by friction forces and their presence greatly impairs aesthetic appearance and wearing comfort.

Previous methods considered for overcoming the pilling problem include, for example: the selection of fibers of the greatest possible lengthv and fineness; the use of fibers of non-circular cross-section, e. g., triangular cross section; the use in preparing woven and knit fabrics of tightly twisted two-ply yarns; the avoidance of high percentages of high strength fibers in fiber blends; as well as others. However, each of the proposed methods is accompanied by deficiencies inpractical use, such as restriction of particularfiber materials, impairment in strength, texture, bulk, and the like properties of the fiber product. Such restrictions also severely limit practical use of synthetic fibers.

Other methods considered are those of chemical treatment of the acrylic fibers. However, none of the suggested chemical treatments was able to avoid fiber discoloration or texture impairment;

As can be readily appreciated, the solution to the problem of pilling of synthetic fibers, including acrylic fibers, has not yet developed to a practical level. Accordingly, an urgent need in the art would be fulfilled if a practical process for reducing the pilling tendencies of acrylic fibers could be provided.

In accordance with the present invention, there is provided a process for reducing the pilling tendencies of acrylic fibers and fiber products thereof which comprises treating an acrylic fiber or product thereof obtained from an acrylonitrile polymer containing at least weight percent acrylonitrile and any balance of one or more ethylenically unsaturated monomers copolymerizable therewith with an aqueous solution containing a salt of an alkyl sulfate of. 8 to 16 carbonatoms, said salt selected from those of sodium, potassium, and ammonium salts, and sodium carbonate, said treatment being carried out at a temperature in the range of about 60 to C. and so as to deposit from about 0.1 to 2.0 weight percent of said alkyl sulfate and from about 0.5 to 3.0 weight percent of sodium carbonate, both percentages based on the dry weight of said fiber or fiber product, and thereafter drying the treated fabric at a temperature in the range of about 60 to l20C.

In carrying out the process of the present invention, an aqueous solution of alkyl sulfate salt and sodium carbonate is prepared and heated to the proper temperature, the acrylic fiber or fiber product is entered into said solution so as to be impregnated "thereby, the amount of impregnant on the fiber or fiber product is adjusted to the proper weight pick-ups of treating agents, and the thus-treated fiber 'or fiber product is then dried at a temperature in the range of about 60 to l20C., whereupon the anti-pilling character is durably imparted.

The term alkylsulfate, as employed herein, is intended to mean a monoalkyl ester of sulfuric acid which is in the form of the sodium, potassium, or ammonium salt. The alkyl group will have from about 8 to l6 carbon atoms in straight or branched chain. A particularly useful alkylsulfate is sodium laurylsulfate because of its availability and cost.

Although the alkylsulfate may impart some improvement in anti-pilling characteristics when used without sodium carbonate, the combination provides markedly superior characteristics.

In Table I, which follows, is shown the relationship between anti-pilling effectiveness and the concentrations of alkylsulfate and sodium carbonate.

TABLE l-Continued Concentrations in weight percent Based on the weight of dry fiber From the data of Table l and additional studies, the effective use levels for obtaining improvement in pilling tendencies of acrylic fibers and products thereof is found to lie in the range of about 0.1 and 2.0 weight percent of alkylsulfate and about 0.5 to 3.0 weight percent of sodium carbonate, both percentages being based on the dry weight of fiber. Preferably, the uses will be about 0.1 to 1.0 weight percent of alkylsulfate and 0.5 to 2.0 weight percent of sodium carbonate based on the dry weight of the fiber.

-The effect of the temperature of fiber treatment on the pilling tendencies thereof using 0.5 weight percent of alkylsulfate and 2.0 weight percent of sodium carbonate is shown in Table II, which follows.

TABLE ll Treating Temperature (C.) Pilling Tendency 20 Moderate to Slight 40 Slight 60 None 80 None TABLE III Drying Temperature (C.) Pilling Tendency 60 Slight to None 80 None 100 Slight to None I20 Slight to None From the data in Table III and additional studies, the effective drying temperature is in the range of about 60 to 120C, preferably about 80C.

In treating acrylic fiber or fiber product therefrom, an aqueous solution containing both alkylsulfate and sodium carbonate is conveniently prepared and the solution heated to an effective treating temperature. The fiber or fiber product is treated so that the proper amount of treating agents are present on the fiber. Adequate pickups can be controlled by the concentration of agents in the treating solution and time of treatment. Excessive pickup may be reduced by appropriate mechanical procedure, i.e., centrifugation, padding, and the like. Neither of the agents is normally substantive to the fiber.

The term acrylic fiber" as used herein, is intended to mean an acrylic fiber obtained from an acrylonitrile polymer containing at least about 80 mol percent of acrylonitrile and any balance of one or more ethylenieally unsaturated monomers copolymerizable therewith.

Suitable comonomers include for example an acrylic acid ester, :1 methacrylic acid ester, acrylamide, methacrylamide, N-substituted acrylamides and methacrylamides, vinyl acetate, vinylpyridine, allylsulfonic acid, methallylsulfonic acid, and the like.

The expression fiber product, as used herein, is intended to mean fibrous constructions containing at least about 50 weight percent of the defined acrylic fiber based on the total product weight. Thus, the product may consist solely of the acrylic fiber or may be a blend thereof with natural fibers such as cotton or wool. The construction may be in the form of fiber, yarn, woven or knit fabric, non-woven fabric, and the like.

wherein the treating agents are combined firmly and deeply penetrated so that the coefficient of friction between fibers is increased, the individual fibers do not become disengaged from one another, and any pills formed freely fall from the fibrous bulk thereby remarkably improving the anti-pilling tendencies of the material treated. in addition, the anti-pilling improvement is highly durable and is not accompanied by any adverse effects on other fiber properties.

The invention is more fully illustrated by the examples which follow, wherein all parts and percentages are by weight unless otherwise designated.

The method of measuring the pilling tendencies is as follows.

The test specimens, are measured using a conventional pilling tester. A fabric in the form of a swatch about 10 X 12 centimeters is wrapped around an appropriate rubber tube, 2.5 centimeter in diameter and 15 centimeter in length. The edges are sown together so as not to overlap one another and the ends are secured to EXAMPLE 1 A jersey cloth composed of 100% acrylic fiber which was yarn-dyed was treated for 10 minutes in an aqueous solution containing 0.5% sodium laurylsulfate and 2.0% sodium carbonate. The acrylic fiber was spun from a polymer containing 89 mole percent acrylonitrile and ii mole percent methyl acrylate. The treatment was carried out at 60C. The treated fabric was centrifuged to adjust the pickup of the fabric to 100%. The fabric was then dried at C. for 30 minutes. The dried fabric was then rinsed with water at room temperature for 5 minutes and allowed to dry at atmospheric conditions.

For comparison purposes, an untreated sample of the same fabric was employed. In addition, two additional comparisons were made, one (Comparative Example A) in which the treating solution contained 0.5% sodium laurylsulfate alone and another (Comparative Example B) in which the treating solution contained 2.0% sodium carbonate alone, the treatments following the procedure above.

The various fabrics were evaluated for pilling tendencies initially and after washing. Washing was with 2 grams per liter of detergent at 40C. for 10 minutes using a 50:1 l'q uorzfabric ratio. followed by rinsing and The present process provides fiber or fiber products I drying using domestic washing and drying equipment. Results are given in Table IV.

TABLE IV Pilling Tendency Sample lnitial After Washing Example 1 None None Comp. Ex. A Slight Moderate Comp. Ex. B Moderate Considerable Considerable Considerable Untreated to Extensive to Extensive EXAMPLE 2 TABLE V Sample Filling Tendency Example 2 Slight to None Untreated Moderate I claim:

1. A process for reducing the pilling tendencies of acrylic fibers and fiber products thereof which comprises treating an acrylic fiber or product thereof obtained from an acrylonitrile polymer containing at least weight percent acrylonitrile and any balance of one or more ethylenically unsaturated monomers copolymerizable therewith with an aqueous solution containing a salt of an 'alkylsulfate of 8 to 16 carbon atoms, said salt selected from sodium, potassium, and ammonium salts, and sodium carbonate, said treatment being carried out at-ayt'emperature in the range of about 50 to C. and so as to deposit from about 0.1 to 2.0 weight percent of said alkylsulfate and from about 0.5 to 3.0 weight percent of sodium carbonate, both percentages based on the dry weight of said fiber or fiber product, and thereafter drying the treated fabric at a temperature in the range of about 60 to l20C.

2. The process of claim 1 wherein the alkyl sulfate is sodium laurylsulfate.

3. The process of claim 1 wherein the alkylsulfate is deposited on said fiber or fiber product at 0.1 to 1.0 weight percent,

4. The process of claim 1 wherein the sodium carbonate is deposited on said fiber or fiber product at 0.5 to 2.0 weight percent.

5. The process of claim 1 wherein the treated fabric is dried at 80C.

6. The process of claim 1 wherein the fiber or fiber product is treated at 60 to 80C.

7. The process of claim 1 wherein the fiber is in yarn form.

8. The process of claim 1 wherein the fiber is in fabric

Claims (8)

1. A PROCESS FOR REDUCING THE PILLING TENDENCIES OF ACRYLIC FIBERS AND FIBER PRODUCTS THEREOF WHICH COMPRISES TREATING AN ACRYLIC FIBER OR PRODUCT THEREOF OBTAINED FROM AN ACRYLONITRILE POLYMER CONTAINING AT LEAST 80 WEIGHT PERCENT ACRYLONITRILE AND ANY BALANCE OF ONE OR MORE ETHYLENICALLY UNSATURATED MONOMERS COPOLYMERIZABLE THEREWITH WITH AN AQUEOUS SOLUTION CONTAINING A SALT OF AN ALKYLSULFATE OF 8 TO 16 CARBON ATOMS, SAID SALT SELECTED FROM SODIUM, POTASSIUM, AND AMMONIUM SALTS, AND SODIUM CARBONATE, SAID TREATMENT BEING CARRIED OUT AT A TEMPERATURE IN THE RANGE OF ABOUT 50* TO 100*C. AND SO AS TO DEPOSIT FROM 0.1 TO 2.0 WEIGHT PERCENT OF SAID ALKYLSULFATE AND FROM ABOUT 0.5 TO 3.0 WEIGHT PERCENT OF SODIUM CARBONATE, BOTH PERCENTAGES BASED ON THE DRY WEIGHT OF SAID FIBER OR FIBER PRODUCT, AND THEREAFTER DRYING THE TREATE FABRIC AT A TEMPERATURE IN THE RANGE OF ABOUT 60* TO 120*C.

2. The process of claim 1 wherein the alkyl sulfate is sodium laurylsulfate.

3. The process of claim 1 wherein the alkyl sulfate is deposited on said fiber or fiber Product at 0.1 to 1.0 weight percent.

4. The process of claim 1 wherein the sodium carbonate is deposited on said fiber or fiber product at 0.5 to 2.0 weight percent.

5. The process of claim 1 wherein the treated fabric is dried at 80*C.

6. The process of claim 1 wherein the fiber or fiber product is treated at 60* to 80*C.

7. The process of claim 1 wherein the fiber is in yarn form.

8. The process of claim 1 wherein the fiber is in fabric form.