US3410647A - Treatment of gelled, swollen polyacrylonitrile type fibers with zinc sulfoxylate formaldehyde, zinc hydrosulfoxylate formaldehyde or zinc hydrosulfite - Google Patents

Description

United States Patent 3,410,647 TREATMENT OF GELLED, SWOLLEN POLY- ACRYLONITRILE TYPE FIBERS WITH ZINC SULFOXYLATE FORMALDEHYDE, ZINC HYDROSULFOXYLATE FORMALDE- HYDE 0R ZINC HYDROSULFITE Julian J. Hirshfeld, Decatur, Ala., assignor to Monsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 134,817, Aug. 30, 1961. This application May 10, 1965, Ser. No. 454,699

4 Claims. (Cl. 8-97) ABSTRACT OF THE DISCLOSURE The invention involves treatment of freshly spun swollen and gelled polyacrylonitrile or polyacrylonitrile fibers with any number of conventional textile reducing agents, e.g. sodium hydrosulfite, formaldehyde sulfoxylate, thiourea dioxide, sodium theosulfate and sodium bisulfite. Specific copolymeric fibers modified by this process are ones made up of a blend of 88% of 94% acrylonitrile and 6% vinylacetate and 12% of another copolymer of 50% acrylonitrile and 50% methyl vinyl pyridine.

This application is a continuation-in-part of application Ser. No. 134,817, filed Aug. 30, 1961, in the name of Julian J. Hirshfeld for Dye Improvement.

This invention is related to an improved process for treating acrylic fibers. More particularly this invention is related to treating acrylic fibers to increase the basic dye uptake thereof.

The problem of dyeing textile fibers composed of at least 75 percent of acrylonitrile has long been a hinderance to the full exploitation of the use of this fiber in the textile field. These fibers are hydrophobic and thus resist the conventional textile dyeing methods. In the past, various methods for dyeing synthetic linear acrylonitrile polymer fibers have been developed. However these methods have not been entirely satisfactory in that there has not been full and deep penetration of the fibers by the dyestufi, leading to crocking; the dyeing is uneven, which sometimes leaves streaks and botches on the fibers; the lightfastness and washfastness of these prior methods are poor because the dyestuffs are located on the periphery of the fibers and thus more susceptible to any physical action which harms the surface of the fibers. Also, the methods of the prior art do not give the best results in dyeing of heavy colors such as black, brown, maroon and navy.

An object of this invention is to provide a process for treating acrylic fibers to increase the dye uptake thereof.

Another object of this invention is to provide a fiber treating process which prevents crocking of acrylic fibers dyed with basic dyestuffs.

Another object of this invention is to provide a process for treating acrylic fibers so that these fibers can be easily dyed in heavy shades.

Other objects and advantagesof this invention will become apparent from the hereinafter detailed description.

The objects of this invention are generally accomplished by passing the acrylic fiber through a conventional finish bath having added thereto a reducing agent such as sodium hydrosulfite. The fiber is in an uncollapsed state just after it has passed through the cascade of the wet spinning system. The finish bath should be acidic in nature; however, this is not a limiting factor.

More specifically, the uncollapsed fibers after leaving the cascade of the wet spinning system are passed through a standard or conventional finish bath which generally is composed of a fiber lubricant such as a wax emulsion, a fiber softener such as ethylene glycol and an anti-static agent such as a quaternary ammonium compound, to which finish bath a reducing agent has been added. The reducing agents which may be used in the practice of this invention are sodium hydrosulfite, sodium sulfoxylate, formaldehyde, zinc sulfoxylate formaldehyde, zinc hydroxy sulfoxylate formaldehyde, modified hydrosulfites, zinc hydrosulfite, a mixture of sodium and zinc sulfoxylate formaldehyde, thiourea dioxide, sodium thiosulfate, and sodium meta bisulfite. The amount of reducing agent, based on the volume of the finish bath, may vary from 0.1 percent to 10 percent with the preferred being 3.0 percent. However, a larger percentage may be used, but it would not be economical and would render the finish bath rather viscous. The pH of the finish bath is not of importance to the process of this invention; however, in order to avoid damage to the fibers, the bath is maintained at a pH in the range of 2 to 7. The temperature of the finish bath may vary from 15 C. to 50 C., however, the temperature range does not effect the process of this invention. Generally it requires only a second or two for the fibers to move through the finish bath.

When the fibers have been dried after passing through the finish bath, the dye uptake of basic dyes is remarkably increased. Thus, with the process of this invention, crocking is reduced to acceptable commercial limits or eliminated all together. The lightfastness and washfastness is excellent compared to previously dyed acrylic fibers. In addition and of extreme importance is that with the process of this invention acrylic fibers may now be successfully dyed in heavy shades which do not bleed, show crocking and maintain excellent washfastness and lightfastness.

While this application has been generally directed to acrylic fibers, it is especially useful in the basic dyeing of polymeric materials which are polyacrylonitrile, copolymers, including binary and ternary polymers containing at least percent by weight of acrylonitrile in the polymer molecule, or a blend comprising polyacrylonitrile or copolymers comprising acrylonitrile with from 2 to 50 percent of another polymeric material the blend having an overall polymerized acrylonitrile content of at least 80 percent by weight. While the preferred polymers employed in the instant invention are those containing at least 80 percent of acrylonitrile, generally recognized as the fiber-forming acrylonitrile polymers, it will be understood that the invention is likewise applicable to polymers containing less than 80 percent acrylonitrile. The acrylonitrile polymers containing less than 80 percent acrylonitrile are useful in forming films, coating compositions, molding operations, lacquers, etc.

For example, the polymer may be a copolymer of from 80 to 98 percent acrylonitrile and from 2 to 20 percent of another monomer containing the (#C linkage and copolymerizable with acrylonitrile. Suitable monoolefinic monomers include acrylic, alpha-chloroacrylic and methacrylic acids; the acrylates, such as methylmethacrylate, ethylmethacrylate, butylmethacrylate, methoxymethyl methacrylate, beta-chloroethyl methacrylate, and the corresponding esters of acrylic and alpha-chloroacrylic acids; vinyl chloride, vinyl fluoride, vinyl bromide, vinylidenc chloride, l-chloro-I-bromo-ethylene; methacrylonitrile; acrylamide and methacrylamide; alphachloroacrylamide; or monoalkyl substitution products thereof; methylvinyl ketone; vinyl carboxylates, such as vinyl acetate, vinyl chlor-oacetate, vinyl propionate, and vinyl stearate; N-vinylimides, such as N-vinylphthalimide and N-vinylsuccinimide; methylene malonic esters; itaconic acid and itaconic esters; N-vinylcarbazole; vinyl furane; alkyl vinyl esters; vinyl sulfonic acid; ethylene alpha, buta-dicarboxylic acids or their anhydrides or derivatives, such as diethylcitraconate diethylmesaconate, styrene, vinyl naphthalene; vinyl-substituted tertiary heterocyclic amines, such as the vinylpyridines and alkyl-substituted vinylpyridines, for example, 2-vinylpyridine, 4-vinylpyridine, Z-methyl-5-vinylpyridine, etc.; l-vinylirnidazole and alkyl-substituted 1-vinylimidazoles, such as 2-, 4-, or S-methyl-l-vinylilidazole, and other C-"C containing polymerizable materials.

The polymer may be a ternary or higher interpolymer, for example, products obtaind by the interpolymerization of acrylonitrile and two or more of any of the monomers, other than acrylonitrile, enumerated above. More specifically, and preferably, the ternary polymer comprises acrylonitrile, methacrylonitrile, and 2vinylpy1'idine. The ternary polymers preferably contain from 80 to 98 percent of acrylonitrile, from 1 to percent of a vinylpyridine or a l-vinylimidazole, and from 1 to 18 percent of another substance such as methacrylonitrile or vinyl chloride.

The polymer may also be a blend of a polyacrylonitrile or of a binary interpolymer of from 80 to 99 percent acrylonitrile and from 1 to 20 percent of at least one other C:C containing substance With from 2 to 50 percent of the weight of the blend of a copolymer of from 10 to 70 percent of acrylonitrile and from to 90 per cent of at least one other C containing polymerizable monomer. Preferably, when the polymeric mate'- rial comprises a blend, it will be a blend of a copolymer of 90 to 98 percent acrylonitrile and from 2 to 10 percent of another monoolefinic monomer, such as vinyl acetate, which is not receptive to dyestuff, with a sufficient amount of a copolymer of substituted tertiary heterocyclic amine, such as vinylpyridine or l-vinylimidazole, to give a dyeable blend having an overall vinyl-substituted tertiary heterocyclic amine content of from 2 to 10 percent, based EXAMPLE 1 Forty grams of fiber composed of at least 80 percent acrylonitrile were removed from the spinning system after it had passed through a standard finish bath composed of a softening agent, a lubricant and an anti-static agent, and had been collapsed and dried. This 40 grams was then introduced into dye bath, ratio of 40 to 1 dyebath to fiber, composed of 26 percent C.I. Basic Blue 22 (Colour Index, published by the Society of Dryers and Colourists and the American Association of Textile Chemists and Colourists, second edition, 1956 an anthraquinone dye), 5 percent of ammonium acetate and 1 percent of acetic acid. This dye bath was brought to the boiling point and maintained at that point for 2 hours. The fiber sample was then withdrawn, rinsed and dried.

Prior to the immersing of the sample into the dye bath and after the two hour boil, the concentration of the dyestutf in the dye bath was determined by the use of a transmission spectrophotometer such as Spectronic 505 made by Bauch & Lomb. The concentration of the dyestufi at the beginning was 26 percent of the Weight of the fiber sample. After the conclusion of the dyeing, it was determined that the concentration of the dyestuff in the dye bath was 18.8 percent calculated on the weight of the sample, thus indicating that the dye uptake of the sample was 7.2 percent calculated on the weight of the sample. This was a control sample without the reducing agent being present in the finish bath.

4 EXAMPLE 2 Forty grams of fiber composed of 92 percent acrylonitrile and 8 percent vinyl acetate were removed from the spinning system after it has passed through a standard finish bath composed of a conventional softening agent, a conventional lubricant, a conventional anti-static agent and 2.1 percent by volume of sodium hydrosulfite and then had been collapsed and dried. To determine the results of the treatment this 40 gram sample was then introduced into a dye bath, ratio of 40 to 1 of dyebath to fiber, composed of 16 percent of Cl. Basic Blue 22, 5 percent of ammonium acetate and 1 percent acetic acid each based on the weight of the sample. This dye bath was brought to the boiling point and maintained at that point for 2 hours. The fiber sample was then withdrawn, rinsed and dried.

Prior to the immersing of the sample into the dye bath and after the two hour boil, the concentration of the dyestuff in the dye bath was determined by the use of a transmission spectrophotometer such as Spectronic 505 made by Bausch & Lomb. The concentration of the dyestuff at the beginning was 16 percent calculated on the weight of the sample. After the conclusion of the dyeing, it was determined that the concentration of the dyestutf in the dye bath was 3.8 percent calculated on the weight of the sample, thus indicating that the basic dye uptake of the sample was 12.2 percent, calculated on the weight of the sample.

EXAMPLE 3 Forty grams of fiber composed of a blend of 88 percent of one copolymer composed of 94 percent acrylonitrile and 6 percent vinyl acetate and 12 percent of another copolymer composed of 50 percent acrylonitrile and 50 percent methyl vinylpyridine were removed from the spinning system after it had passed through a standard finish bath composed of a conventional softening agent, a conventional lubricant, a conventional anti-static agent and 2.1 percent by volume of sodium hydrosulfite and then had been collapsed and dried. To determine the results of the treatment this 40 grams sample was then introduced into a dye bath, ratio of 40 to 1 of dye bath to fiber, composed of 16 percent of C.I. Basic Blue 22, 5 percent of ammonium acetate and 1 percent of acetic acid each calculated on the weight of the sample. This dye bath was brought to the boiling point and maintained at that point for 2 hours. The fiber sample was then withdrawn, rinsed and dried.

Prior to the immersing of the sample into the dye bath and after the two hour boil, the concentration of the dyestuff in the dye bath was determined by the use of a transmission spectrophotometer such as Spectronic 505 made by Bausch & Lomb. The concentration of the dyestutf at the beginning was 16 percent calculated on the weight of the sample. After the conclusion of the dyeing, it was determined that the concentration of the dyestutf in the dye bath was 4 percent, calculated on the weight of the sample thus indicating that the basic dye uptake of the sample was 12 percent calculated on the weight of the sample.

EXAMPLE 4 The process of Example 2 was repeated except 0.2 percent by volume of sodium hydrosulfite was used in the finish bath. The concentration of the dyestufi in the dye bath after the dyeing operation, which was used for testing purposes, was completed was 5.8 percent indicating basic dye uptake of 10.2 percent.

EXAMPLE 5 The process of Example 2 was repeated except 3 percent by volume of sodium hydrosulfite was used in the finish bath and 26 percent by weight of the sample of Cl. Basic Blue 22 was used in the testing dye bath. The concentration of the dyestufi in the dye bath after the dyeing operation was completed was 10.3 percent indicating a basic dye uptake of 15.7 percent.

EXAMPLE 6 The process of Example 5 was repeated except 4 percent by volume of sodium hydrosulfite was used in the finish bath. The concentration of the dyestuif in the testing dye bath after the dyeing operation was completed was 11 percent indicating a basic dye uptake of percent.

EXAMPLE 7 The process of Example 5 was repeated except 5 percent by volume of sodium hydrosulfite was used in the finish bath. The concentration of the dyestuif in the testing dye bath after the dyeing operation was completed was 10.3 percent indicating a basic dye uptake of 15.7 percent.

EXAMPLE 8 The process of Example 5 was repeated except 3 percent by volume of sodium sulfoxylate formaldehyde was used in the finish bath. The concentration of the dyestuif in the dye bath after the dyeing operation was completed was 11.4 percent indicating a basic dye uptake of 14.6 percent.

EXAMPLE 9 The procedure of Example 8 was repeated except a 3 percent by volume, a 4 percent by volume and a 5 percent by volume of sodium meta bisulfite were added respectively to the finish bath. The concentration of the dyestuffs respectively in the dye baths, after the dyeing operations were completed, were 10.0 percent, 10.6 percent and 10.7 percent indicating basic dye uptakes of 16.0 percent, 15.4 percent and 15.3 percent respectively.

EXAMPLE 11 The process of Example 8 was repeated except a 3 percent by volume, a 4 percent by volume and a 5 percent by volume of zinc hydrosulfite were used respectively in the finish bath. The concentration of the dyestuffs respectively in the dye bath after the dyeing operations were completed were 14.9 percent, 15.0 percent and 15.6 percent respectively indicating basic dye uptakes of 11.0 percent, 11.0 percent and 10.4 percent.

When the results of the basic dye uptake of the fibers which were treated with a reducing agent in the finish bath are compared to the control example which did not have the reducing agent in the finish bath, the tremendous improvement of the uptake of the basic dye is obvious. In several instances the improvement was over percent which greatly aids the further use of acrylic fibers in the textile field. The amount of reducing agent picked up by the fiber in the finish bath is less than about 5 percent by Weight of the fiber and is usually in the range of 3-5 percent when the process is carried out as in the above examples.

Many modifications of the above will be obvious to those skilled in the art without a departure from the inventive concept.

What is claimed is:

1. The method of treating synthetic linear acryonitrile fibers to increase the basic dye uptake thereof; comprising contacting the freshly spun fibers with a wet finish bath having added thereto a reducing agent selected from the group consisting of zinc sulfoxylate formaldehyde, zinc hydrosulfoxylate formaldehyde and zinc hydrosulfite; said contacting taking place when the fiber is in an uncollapsed, unoriented condition.

2. The method of claim 1 in which the reducing agent is zinc sulfoxylate formaldehyde.

3. The method of claim 1 in which the reducing agent is zinc hydrosulfoxylate formaldehyde.

4. The method of claim 1 in which the reducing agent is zinc hydrosulfite.

References Cited UNITED STATES PATENTS 2,899,262 8/1959 Stanton et al. 26478 X 2,936,211 5/1960 Kocay.

3,089,748 5/1963 Mogenson et al.

3,091,552 5/1963 Furness et al.

3,083,111 3/1963 Bridgeford.

OTHER REFERENCES Thorne et al., Ephraims Inorganic Chemistry, 4th edition, pages 543 and 544, pub. 1943 by Oliver and Boyd Ltd., Edinburgh, Scotland.

NORMAN G. TORCHIN, Primary Examiner.

DONALD LEVY, Assistant Examiner.