US 3005730 A
Description (OCR text may contain errors)
1951 c. E. PARDO, JR. ET AL 3,005,730
SHRINKPROOFING OF WOOL WITH N,NMETHYLENE BIS-ACRYLAMIDE POLYMERIZED IN SITU AND THE MODIFIED WOOL Filed 001:. 25, 1954 --Protein fiber (Wool) l Impregnate fiber with solution of reducing agent 2/ such as hydrazine sulphate,
ferrous sulphate, alkali metal bisulphite, etc.
Impregnate fiber with solution of N,N'-methylene bis-acrylamicle and oxidizing agent, e.g.,hydrogen peroxide, benzoyl peroxide, tert. butyl hydroperoxide, etc.
/ Protein fiber (Wool) 5 having N,N'-methylene 4 bis-acrylamide polymerized in situ thereon Reducing agent and oxidizing agent constitute a redox catalyst INVENTORS system BY C.E.Pardo,Jr. and HP. Lundgren United States Patent Ofiice 3,005,730 Patented Oct. 24, 1961 A non-exclusive, irrevocable, royalty-free license in the invention herein described, for all governmental purposes, throughout the world, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.
This invention related to processes for shrinkproofing and feltproofing proteinous fibers, particularly wool. A
particular aspect of the invention concerns the provision of process where N,N-methylene bis-acrylamide is polymerized on the fibers whereby to produce a modified fiber which exhibitis a marked resistance to shrink-age as compared with the original fiber. Further objects and advantages of the invention will be obvious from the description herein.
It is well known that laundering causes severe shrinkage of woolen textiles. This technical disadvantage seriously restricts the applications of wool in the textile industry and much research has been undertaken to modify the natural fiber to reduce its shrinkage properties. In general treatments wherein resinous materials are coated on or formed in the fiber have given the desired result of reducing shrinkage but in most cases so much of the resinous material must be incorporated in the wool that the modified fiber lacks the hand of the natural fiber, tending to be somewhat harsh or even boardy.
It has now been-found that when the compound N,N'- methylene bis-acrylamide is polymerized in situ in the fibers, the resulting modified fiber exhibits a drastically decreased shrinkage as compared with the original fiber. At the same time, only a small proportion of the amide need be incorporated in the fiber to obtain this efiect so that the modified fiber has virtually the same hand as the untreated fiber. In addition, it has been observed that this treatment does not cause any discoloration of the fiber nor does it impair tensile strength.
The shrinkproofing treatment in accordance with this invention involves essentially applying N,N'-methylene bis-acrylamide to the wool in the presence of a redox catalyst system. Such a system includes a reducing agent and an oxidizing agent, the interaction of these agents providing free radicals which cause polymerization of the amide on the wool. Any of the redox catalyst systems suitable for the polymerization of vinyl compounds can be used. Thus for example the reducing agent may be a ferrous salt such as ferrous sulphate, acetate, phosphate, ethylenediaminetetraacetate, etc.; an alkali metal bisulphite or sulphite; sulphur dioxide; sulphurous acid and so forth. It is preferred to use a salt of hydrazine as the reducing agent because when such reagent is used the treated wool is whiter than the original wool. This is in contrast to the use of ferrous salts in which case the treated wool is often stained or discolored. The important aspect of the preferred reducing agent is the presence of the hydrazine radical; the acid moiety of the salt may be derived from any acid, as for example, bydrochloric, hydrobromic, sulphuric, sulphurous, phosphoric, benzoic, acetic, etc. The hydrazine may be completely or only partly salified by the acid.
As the oxidizing agent in the redox system one may use such agents as hydrogen peroxide, benzoyl peroxide, acetyl peroxide, tertiary butyl hydroperoxide, alkali metal involves first impregnating the fiber with a solution of a reducing agent. The fiber containing the reducing agent is then put into a bath containing the amide and the oxidizing agent whereby the amide will be polymerized on the fiber. If desired the sequence may be altered so that the fiber is first impregnated with the amide and one of the redox pair, for instance the reducing agent. The impregnated fiber is then placed in a bath containing the other redox catalyst (the oxidizing agent in this case) whereby the amide will be polymerized on the fiber. Other variations of the sequence in which the reagents are applied will be obvious to those skilled in the art.
The first technique described above is diagrammatically illustrated in the accompanying drawing. Referring thereto, protein fiber 1 is impregnated in step 2 with a solution of the reducing agent. The resulting treated fiber is then impregnated in step 3 with a solution of N,N'-methylene bis-acrylamide and the oxidizing agent. There is thus produced a protein fiber 4 having N,N'- methylene bis-acrylamide polymerized in situ thereon.
In treating the fiber with the solutions of the N,N'- methylene bis-acrylamide and the redox catalysts, it is preferred that the solutions contain a wetting agent to enhance the penetration of the reagents into the fiber. One may use for this purpose any of the agents which possess surface-active properties and are useful in wetting and detergent applications. Such agents are exemplified by soap, long chain alkyl sodium sulphates or 'sulphonates, sodium alkyl benzene sulphonates, sodium alkyl phenol sulphonates, sodium di-alkyl sulphosuccinates, sulphated or sulphonated esters or amides of high-molecular weight fatty acids, and so forth. There may also be used non-ionic surfaceactive agents such as for example mannitol laurate and ethylene oxide reaction products with fatty acids, fatty alcohols, polyhydric alcohols, or with esters of polyhydric alcohols and high molecular weight fatty acids.
The time of treatment of the fiber with the amide and the redox catalyst system may be varied in accordance with the concentration of the amide in the treatment solution, the temperature and the amount of modification of the fiber desired. In many cases, a treatment time of 30 minutes is adequate to obtain a high degree of shrinkproofing. The temperature of the treatment is usually about 40 C. or above. To prevent damage to the wool it is preferred to use a temperature not higher than about C. A reaction temperature of about 60 C. is preferred as yielding rapid polymerization Without damage to the fiber. Such conditions as concentration of reagents, time and temperature of reaction, etc. are not critical but may be modified to suit individual circumstances without changing the basic nature of the present invention. In general the shrinkproofing efiect will increase with increasing uptake of amide but not necemarily in linear proportion. As shown in the examples hereinafter uptakes of the amide on the order of 10% will virtually eliminate shrinkage. It is obvious that, depending on the desired effect, more or less of the amide may be polymerized on the fiber. In general uptakes in the range from about 5% to about 15% are preferred.
The process of the present invention is applicable generically to proteinous fibers or their mixtures with other textile fibers whether the fibers are in such form or in the form of thread, yarn, knitted goods, woven goods, and so forth. The invention is particularly adapted to the treatment of wool but may also be applied to other proteinous fibers such as silk, fur, mohair, other fibers from fleece-bearing animals, synthetic protein fibers made from zein, peanut protein, casein, keratins, etc.
The invention is further demonstrated by the following example. Example I An aqueous solution containing 0.5% hydrazine sulphate and 0.05% of sodium alkyl (C -C benzene sulphonate was prepared. Swatches of woolen cloth were immersed in the solution then centrifuged to remove the excess liquid. The swatches were then each immersed in an aqueous solution containing N,N-rnethylene bis-acrylamide (concentration specified below), 0.5% hydrogen peroxide, and 0.05% sodium alkyl (C C benzene sulphonate. The solutions were maintained at 60 C. and the cloth samples were kept therein for various lengths of time (as specified below). The samples were then removed from the solution and centrifuged to remove excess liquid then washed thoroughly to remove the unreacted materials. The treated samples were subjected to analysis to determine the uptake by the fibers of the amide. Samples of the treated cloth and a sample of the orginal, untreated cloth were subjected to a standard laundering technique and the area shrinkage of each sample was then determined. The conditions used and the results obtained are tabulated below:
Concentration Uptake of Area of N ,N-meth- Time of N,N-methshrinkage Sample ylene bisreaction, ylene bisafter acrylamide in minutes acrylamide, laundering, treating bath, percent percent percent catalyst system to polymerize the N,N'-methylene bisacrylam-ide in situ on the said proteinous textile fibers.
3. A process for shrinkproofing wool fibers comprising treating the wool fibers with N,N'-methylene bisacrylamide in the presence of a redox catalyst system to polymerize the said N,N'-methylene bis-acrylamide in situ on the said wool fibers.
4. A process for shrinkproofing wool fibers comprising impregnating the wool fibers with a hydrazine salt and then treating the impregnated wool fiebrs with a solution containing N,N-methylene bis-acrylamide and aperoxygen compound to polymerize the said N,N'- methylene bis-acrylamide in situ on the said wool fibers.
5. A process for shrinkproofing wool fibers comprising impregnating the wool fibers with hydrazine sulfate and then treating the impregnated wool fibers with a solution containing N,N-methylene bis-acrylamide and hydrogen peroxide to polymerize the said N,N'-rnethylene bisacrylamide in situ on the said wool fibers.
6. A modified proteinous fiber which exhibits reduced shrinkage properties as compared with the unmodified proteinous fiber comprising a proteinous fiber having N,N-methylene bis-acrylamide polymerized in situ there- 7. A modified proteinous textile fiber which exhibits reduced shrinkage properties as compared with the unmodified proteinous textile fiber comprising a proteinous textile fiber having N,N-methylene bis-acrylamide polymerized in situ thereon.
8. A modified wool fiber comprising a wool fiber having N,N'methylene bis-acrylamide polymerized in situ thereon.
References Cited in the file of this patent UNITED STATES PATENTS Strain Sept. 12, Lundberg July 12, Jones May 23, Kropa June 3, Hammer et al. July 7, Melamed Dec. 13,
FOREIGN PATENTS Great Britain Apr. 7, Great Britain Oct. 31,
OTHER REFERENCES Lipson et al.: Formation of Polymers in Textile Fibres, Nature, vol. 157, No. 3992, May 4, 1946, p. 590.