US3477803A - Shrinkproofing of wool top by using process of interfacial polymerization - Google Patents

Description

Nov. 11. 1969 WTLUE FONG ET AL 3,477,803

SHRINKPROOFING OF WOOL TOP BY USING PROCESS OF INTEHFACIAL POLYMERIZATION Filed Aug. 11, 1964 WOOL TOP 3 AQUEOUS DIAMINE 5M DIACID CHLORIDE SOLUTiON IN ORGANIC sOLvENT 1A D F C?) F L? -11 WATER AQUEOUS DRYER WASHING M7 (RINSE) SOLUTION DRY SHRINKPROOF TOP MECHANICAL. WORKING MYAR N PRODUCTlON OF FINAL PRODUCTS,e.g.,WOVEN F OR KNlTTED FABRICS w. FONG, W.L.WASLEY, R.E.WH|TFIELD, L.A. MILLER 2 l ENTORs BY 3 M A TORNEYS United States Patent 3,477,803 SHRINKPROOFING OF WOOL TOP BY USING PROCESS OF INTERFACIAL POLYMERIZATION Willie Fong, Richmond, William L. Wasley, Berkeley, Robert E. Whitfield, Pleasant Hill, and Lowell A. Miller, Walnut Creek, Calif., assignors to the United States of America as represented by the Secretary of Agriculture Filed Aug. 11, 1964, Ser. No. 388,962 The portion of the term of the patent subsequent to Sept. 9, 1986, has been disclaimed Int. Cl. D06m 3/04, 3/10, 13/54 U.S. Cl. 8-127.6 Claims ABSTRACT OF THE DISCLOSURE Wool fibers in pre-yarn condition is subjected to interfacial polymerization process comprising treatment with a highly alkaline aqueous solution of a monomeric diamine followed by treatment with a water immiscible solution of a monomeric bifunctional organic compound capable of forming a polymer with the diamine. The fibers may subsequently be formed into yarns and the yarns converted into fabrics.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sub-licenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to and has among its objects the shrinkproofing of wool textiles, using novel processes applied to the wool while it is in the form of top or other form wherein mechanical working is required after the shrinkage treatment to yield a finished product such as a yarn or fabric. Further objects of the invention will be evident from the following description wherein parts and percentages are by Weight unless otherwise specified.

The single figure in the annexed drawing is a schematic diagram depicting the various steps in the process of the invention.

In the processing of wool, an initial step is to scour the raw wool with aqueous detergent media to remove the grease, suint, and dirt which make up almost half the weight of the fleeces. The scoured wool is then dried and carded. In the worsted system, the carded wool is subjected to a series of mechanical operations which may generically be termed as drawing or working. The operations include, for example, gilling, combing, and doubling and are usually repeated several times in various sequences depending on the system of working being used and the type of yarns to be eventually produced. The operations result in reducing the thickness of the card sliver (the product of the carding operation), straightening and parallelizing the fibers, removing short fibers (noils), trash, etc., and rendering the strand uniform in regard to weight per unit length and in regard to its content of different kinds of wool fiber present in the original batch. The resulting refined material, generally referred to in the trade as wool top, is a well known article of commerce. It is a thick, but very open and loosely assembled strand of wool fibers with no twist. Generally, the diameter will be about 2 inches. However, because of its soft and open texture, this figure changes drastically with any slight tension and its dimensions are more accurately described by weight per unit length. For example, a typical wool top will weigh about 300 grains per yard. In subsequent operations wool top is used to produce yarns. Thus it is subjected to further working as explained above but with added twisting operations to provide tensile strength. The resulting yarns are then subjected to operations such 3,477,803 Patented Nov. 11, 1969 ICC as weaving or knitting to produce fabrics. The invention is particularly concerned with the treatment of wool while it is in an early mechanical stage of manufacture. Wool in such stage is referred to herein as wool in a pre-yarn condition and includes such materials as scoured wool, card sliver, top, or other assemblies of Wool fibers which require further mechanical treatment before they are formed into yarns. The invention is particularly adapted for treating wool in the form of top since in this state it is available in long strands, hence well adapted for continuous operations.

In the patent of Miller, Whitfield, and Wasley (3,078,- 138, issued Feb. 19, 1963) there are disclosed processes for shrinkproofing Wool wherein a condensation polymer-typically a polyamide-is formed in situ on the wool fibers and grafted to the wool, that is, chemically combined therewith. In a typical embodiment of their process, a wool fabric is serially impregnated with two solutionsthe first being a solution of a diamine in Water, the second being a solution of a diacid chloride in a waterimmiscible, volatile, inert solvent. By such treatment the fibers are coated with superposed layers of the mutuallyinsoluble solutions: an inner layer of diamine in water and an outer layer of diacid chloride in water-immiscible solvent. Under these conditions the diamine and diacid chloride react almost instantaneously at. the interface between the phases, producing in situ on the fibers a highmolecular weight, resinous polyamide which coats the fibers and renders the fabric shrinkproof without detriment to the hand, porosity, and othervaluable properties of the fabric. Moreover, the polyamide is chemically bonded to the wool so that the shrinkproofing eifect is highly durable, i.e., the polyamide deposit is not removed by repeated washing of the treated fabric in conventional soap and water or detergent and water laundering formulations, or in conventional dry cleaning formulations. From a procedural standpoint, the process has the advantage of simplicity and rapidity in that the basic operation is simply a serial impregnation of the fabric in the two solutions. Another point is that the process does not require any heat-curing of the treated fabric as is commonly necessary in most resin shrinkproofing procedures.

In the copending patent application of Fong, Brown, Wasley, Whitfield and Miller (Ser. No. 174,315, filed Feb. 19, 1962, now abandoned) there are disclosed modifications of the above-described procedure whereby long lengths of wool textiles can be shrinkproofed continuously and at high production rates.

In accordance with the present invention, important advantages are gained by applying the above-described system of shrinkage control to wool textiles not in a manufactured state but while they are in an early stage of their manufacture, for example, while they are in the state of a loose assembly of wool fibers, such as wool top. Typical advantages to be gained are these: For one thing, it makes the operation more flexible and permits one to produce a greater variety of textile products. As an example, the treatment may be applied to wool top and the resulting resin-treated wool fibers blended with other fibers-cg, nylon, cotton, cellulose acetate, polyacrylic fibers, etc. which do not require shrinkproofing or which are not intended to be subjected to the shrinkproofing treatment, in order to obtain special structural or decorative effects in the finished product. Such a selective result-limiting the resin treatment to the wool fibersis obviously impossible if the treatment is applied to the already-blended yarn or fabric. Another point is that in certain cases-as in the fabrication of socks, mufflers, sweaters, caps, etc.

would be impossible; the garments would have to be treated batchwise. However, if the shrinkproofing were done at an early stage in manufacture, for example, while the wool was still available in long lengths, this problem would not be encountered and continuous techniques could be used. Another advantage in applying the resin treatment to wool in an ealy stage of its manufacture is that one minimizes such problems as stiffening effects caused by yarn-toyarn or fiber-to-fiber bonding, inadequate shrinkage control because of non-uniform penetration of treatment solutions into thick and/or tightly-woven fabrics, problems of creasing or wrinkling during resin treatment, etc. We have found, however, that totally unexpected problems arise when the shrinkage control methods outlined above are applied to wool in a state in which it must be subjected to further mechanical working. It is to this problem and its solution that the present invention is particularly directed.

The nature of the problem dealt with by the invention is most clearly explained by the following. Where wool in a pre-yarn conditiontypically wool topis treated by the aforesaid shrinkproofing techniques under conditions which provide completely satisfactory results with woven fabrics, the product is not well adapted for further manufacturing steps. One item is that the fibers are so matted together it is difiicult to dry the product. Also, because of this matting effect when the product is subjected to conventional mechanical Working such as gilling, normal processing is almost impossible and there is excessive breakage of fibers, resulting in formation of a large percentage of noils and production of yarns low in tensile strength (because of shortness of individual fibers). Moreover, during the mechanical working steps, a dust of resin particles is detached from the fibers, due to mechanical abrasion. This results in gumming up the fine working parts of the gills, combs, rolls, aprons, spinning gear, etc., and creates a severe dust condition in the surrounding atmosphere.

In accordance with the present invention the basic principles of the aforesaid Miller et al. and Fong et al. processes are utilized in conjunction with a novel system of control whereby to obviate the above problems. More particularly, by applying the teachings of the present invention, one is enabled to provide shrinkage control to wool while it is in a pre-yarn condition and with retention of its mechanical workability so that it is amenable to conventional manufacturing operations. Specifically, the product can be dried readily, it can be mechanically worked on conventional wool-processing machinery without excessive fiber breakage and without dusting or resin rub-off, and it retains its shrink-resistant nature so that this valuable property is carried over to the final products, such as woven or knitted fabrics. Another advantage of the invention is that the treatment may be carried out continuously and at high production rates.

A total system which utilizes the novel process of the invention as applied to wool top is explained in detail below, having reference to the annexed drawing. The liquids for treating the wool top, such as the diamine and diacid chloride solutions, are maintained in tanks provided with conventional devices such as guide rolls and driven rolls to transport a parallel series of continuous strands of Wool top from one solution to the next. In some cases it is preferred to compress the strands between endless driven mesh belts by which the strands are conveyed through the solutions. This system of conveyance is particularly desirable in passing the wool through the diamine solution as it avoids any possibility of tearing, as might happen if tension is applied directly to the strands. Other conventional auxiliary equipment which is provided includes pressing rolls to remove excess liquid from the strands; heating jackets to control temperature of the solutions, etc. One may also provide hoods or housing over the tanks to minimize evaporation of solvents and, in the case of the diamine solution, to minimize contact of CO from the atmosphere with the diamine solution still in the tank or deposited on the strands.

W001 top 1 is unwound from reel 2 and fed into tank 3 wherein it is conveyed through an aqueous solution of a diamine under conditions to insure rapid and uniform exhaustion of the diamine onto the wool fibers. Upon leaving the diamine solution, the top is passed through press rolls 4 to remove excess liquid. The top then enters tank 5 wherein it is conveyed through a solution of a diacid chloride dissolved in an inert, volatile, essentially water-immiscible solvent. Upon leaving the diacid chloride solution the top is passed through press rolls 6 to remove excess solution. The top 1A, now having a polyamide formed in situ on its fibrous elements and chemically bonded to the wool, enters tank 7 wherein it is washed with a conventional washing mediumwarm water containing a small percentage of soap or a synthetic detergent-in order to remove unreacted reagents, solvent, and any particles of resinous reaction product which are not bonded to the wool fibers. Preferably, the washing medium is made slightly acid-for example, by the addition of sufiicient acetic or formic acid to give a pH of about 4 to 5whereby to neutralize any residual alkaline material carried over from the treating solutions.

Following the washing, the top is passed through press rolls 8, then rinsed with water in tank 9, and pressed between rolls 10 to remove excess water. The washed and rinsed top then is conveyed to drier 11 wherein it is dried in a current of warm air. The product 1B is wool top in a shrinkproof condition which can then be subjected to mechanical operations without encountering any diificulties and without loss of its shrinkproof character. Typical manufacturing steps to which the top is subjected are represented by block 12 wherein the top is converted by gilling, drawing, roving, and spinning operations into yarns. The resulting yarns, 1C, may then be manufactured (block 13) into such items as woven or knitted fabrics or they may be directly manufactured into knitted garments such as hose, sweaters, caps, etc. Since the shrinkproof character originally imparted to the top is retained through mechanical working, all of such final products will exhibit a shrinkproof character.

As noted hereinabove, in order to attain effective results, it is necessary that certain conditions be observed during the treatment. These critical factors of the invention are listed and explained below:

One critical factor is that the diamine solution must be dilute in order to minimize inter-fiber resin formation which would cause fiber bonding or matting and resin dusting. We have found that the concentration of diamine must be less than 0.5%. The preferred diamine concentration is 0.25% and in general, concentrations from 0.1 to 0.3% give excellent results. Another critical factor is the pH of the diamine solution. It must be strongly alkaline, i.e., have a pH of at least 12 to 12.5, in order to achieve adequate shrinkproofing. To attain this condition it is necessary to add to the diamine solution a strongly alkaline material, as, for example, sodium or potassium hydroxide, sodium metasilicate, trisodium phosphate, or mixtures of such reagents. In any particular case the amount of alkaline agent added is that required to give the diamine solution a pH of at least 12 to 12.5. Generally, sodium metasilicate is preferred as providing especially good results which are over and above those attributable to its ability to establish a high pH. The reasons for the effectiveness of low diamine concentration and high pH arebelieved to involve the following: When Wool fiberts are successively treated with (1) aqueous diamine solution and (2) diacid chloride in a water-immiscible solvent, a polyamide resin is formed and this resin is chemically bonded (grafted) to the wool, to a greater or lesser extent depending on the conditions of reaction. It is believed that the factors of low diamine concentration and high pH enhance the degree to which this chemical bonding occurs, or, conversely, decrease the degree to which mere physical adherence of resin to fibers is involved. As a net result, the resin is so intimately bonded to the individual fibers that it is not rubbed off when the fibers are subjected to the severe stresses encountered in mechanical working and a superior shrink-resist treatment is achieved. It is also believed that the use of a low diamine concentration is beneficial as encouraging penetration of diamine into the structure of individual fibers and as decreasing the amount of diamine which exists in interstitial areas between fibers whereby the possibility of forming undesirable fiber'to-fiber bonding is decreased. Also, formation of extraneous, loosely-adhering surface resin is prevented. In other words, a matting effect with consequent resin dusting during processing is avoided. However, regardless of any theoretical considerations we have made comparative tests which demonstrated that the conditions described above provide useful results, whereas conditions outside these ranges give inferior results. For example, operating at a pH level of 10.5 to 11 (achieved by the addition of sodium carbonate) and a diamine concentration of 0.1 to 0.3% results in an open strand with little fiber-to-fiber bonding but shrinkproofing is inadequate. If the diamine concentration is raised to a level of 0.5 to 1% to compensate for this defect, while operating at the same pH of 10.5 to 11, the strand is adequately shrink resistant but is matted so that when it is subjected to mechanical working there is considerable fiber breakage and resin dusting, eventually leading to loss of the shrinkage protection.

It is recognized that Miller et al. (US. Patent 3,078,- 138) advocate addition of an alkaline agent-such as sodium carbonate-to the diamine solution to act as an HCl-acceptor, that is, to take up the hydrogen chloride formed in subsequent reaction of the diamine with the diacid chloride. However, in accordance with the present invention, it is not just a matter of HCl-acceptance. Stronger alkaline agents are used to provide pHs far greater than required for HCl-acceptance whereby to achieve novel results never contemplated by the patentees. For example, addition of sodium carbonate to provide a pH of 10.5-11 is more than adequate for HCl-acceptance but does not attain the results obtained as described herein when, for example, sodium metasilicate is added to provide a pH of about 12. In fact, the pHs used in accordance with the invention are so high that they would have been considered as deleterious to the wool.

In utilizing the present invention in the continuous shrinkproofing of wool, it is preferred to include in the total system the features disclosed in the copending application of Fong, Brown, Wasely, Whitfield and Miller, Ser. No. 174,315, filed Feb. 19, 1962, now abandoned and in the copending application of Miller and Fong, Ser. No. 325,195, filed Nov. 20, 1963, now Patent 3,243,253. Although these features form no part of the present invention, they are explained herein to provide a complete description of the preferred environment in which to utilize the present invention. The features in question are described in the following paragraphs, numbered 1 to 6:

(1) Condition of wool.The wool prior to entering the first (diamine) solution should be in a neutral or alkaline state, that is, its 'pH should be at least 7. If it is in an acid state (as may be encountered with carbonized wool or wool dyed in acid dye baths) the diamine solution does not properly impregnate and exhaust onto the wool, with the end result that the degree of shrinkproofing or the uniformity thereof is adversely affected. However, where the material is in a neutral condition as it enters the diamine solution, a complete and uniform penetration of the solution and exhaustion of the diamine into the fibers is obtained wtih the result that the product exhibits a high and uniform degree of shrink resistance. Taking into account these considerations, if the material to be treated is in an acid state, it must be neutralized prior to entry into the diamine bath. \Such neutralization can be accomplished by soaking it in an aqueous solution of an alkaline substance, preferably one which has inherent buffering capacity. Thus, for example, the fabric may be soaked in a dilute (about 0.1 to 5%) solution of an alkaline agent such as sodium carbonate, sodium bicarbonate, borax, trisodium phosphate, tetrasodium pyrophate, sodium metaphosphate, ammonia, sodium acetate, soap, or the like. After such treatment, the wool may be rinsed in water and is then dried or directly entered into the diamine solution.

(2) Temperature of diamine solution.--Another item is that the temperature of the diamine solution should be maintained at a temperature of about to 150 F., preferably about F. Thus it has been observed that at temperatures substantially below the stated level, the penetration and rate of exhaustion of the diamine solution into the material is too slow for continuous operation. On the other hand, at temperatures much above F. the quality of the wool may be adversely affected by yellowing or other degradation changes. By operating within the stated temperature range, penetration of the diamine solution into the material and exhaustion of the diamine onto the fibers occur at a high rate and uniformly, without adverse effect on the quality of the wool. In general, the temperature which provides optimum results will vary with the nature of the diamine used, openness of the material being treated, and time of immersion. In the case of hexamethylene diamine and when treating wool top, optimum results are obtained where the solution is held at about 140 F.

(3) Time of contact between wool and diamine solution.-As noted above, successful operation of the continuous operation requires a thorough and uniform impregnation of the diamine solution into the material and time for adsorption of diamine by the wool (i.e., exhaustion of the diamine onto the wool). These processes are not instantaneous even with an efficient wetting agent incorporated into the diamine bath and therefore the material must be held in contact with the solution for a substantial period of time long enough to attain the desired results. In continuous operation the time of contact can be extended without slowing the production rate by threading the material back and forth in a tank filled with the diamine solution. In any particular case the time of such holding or delay will vary depending upon a series of factors including density and pH of the material, the temperature of the diamine solution, the particular diamine used and its concentration, the type and concentration of wetting agent added to the diamine solution, etc. For example, a matted material such as scoured wool would require a longer delay time than an open material like top. A higher temperature of the diamine solution would increase the penetration rate and so shorten the minimum delay required. A material initially low in pH would require a longer period of delay than one which was at a higher pH prior to contact with the diamine solution. Generally speaking, a diamine of higher molecular weight or one applied in higher concentration would increase the viscosity of the solution and thus in either of these cases a longer delay would be necessitated. Addition of an effective wetting agent to the diamine solution would shorten the delay period below the levels required, for example, with a solution without a wetting agent. Taking into account these manifold circumstances, it is impossible to set forth the time of delay in numerical limits. However, given any particular set of materials, apparatus, and conditions, the required time of delay can be ascertained by pilot trials employing different periods of delay and selecting the one which attains the: desired goal of providing wool fibers which are thoroughly and uniformly impregnated with the diamine solution. In a typical situation where the textile is a wool top, where the diamine is hexamethylene diamine applied in a concentration of about 0.25%, at pH 12, and the solution held at 140 F. contains an effective wetting agent, the proper holding time is at least 10 seconds, but no more than 30 seconds, to minimize possible alkali damage and yellowing. If the temperature is lowered to 110 F. an immersion time of 45-60 seconds is required for adequate results.

(4) Removal of excess liquid after impregnation with the diamine solution.After thorough impregnation with the diamine solution is assured, the material is then subjected to a treatment to eliminate excess liquid (diamine solution and/or water). The aim here is to provide a material wherein the diamine solution is, for the most part, distributed on the surfaces of the individual fibrous elements. Expressed another way, the material is treated to remove essentially all the solution which is loosely associated therewith, as in the form of surface depOSits or collected in interstices between individual fibrous elements, leaving that portion of the solution which coats the' fibers. By such treatment one minimizes the formation of resin deposits on the surface of the wool and in interstitial areas. If such resin deposits were formed, the treated strand would be more matted and resin dusting in mechanical processing would increase. Moreover, by

removal of excess solution, one decreases the amounts of water, diamine, etc. which are adventitiously dislodged from the wool as it enters the second solution. This removal of excess solution can be readily accomplished with the usual types of equipment generally used in finishing fabrics, for example, squeeze rolls, vacuum slots, air jets, hot air driers, or combinations of these devices. A preferred technique is the use of a three-roll padder with threading arrangement to give two nips. Regardless of the means used to effectuate the removal of liquid, the treatment is applied to the extent necessary that the material exhibits a weight increase (wet pick-up) of 30 to 60%, preferably less than 55%. By so doing, the desired result of substantially limiting the liquid in the material to a coating on individual fibers is achieved. At this point the materal will generally contain about 0.1 to 2% of diamine, based on the dry weight of the fibers.

Final padding.Following its passage through the second (diacid chloride) bath, the material is subjected to padding (pressing). This treatment not only removes unreacted reagents, solvents, etc. but also enhances the shrinkproofing effect. The theoretical basis of this effect is not understood but experimental trials have demonstrated that padding is markedly beneficial to the shrink resistance of the product. Good results in this regard are attained by pressing the textile material at a pressure of at least 100 lbs. per linear inch (measured across the width of the material) and even better results are attained with pressures as high as 300-400 lbs. per linear inch.

(6) In continued operation of the system, material from the first (diamine) solution will be detached from the textile material and mix with the second (diacid chloride) solution. This causes such problems as evolution of corrosive HCl fumes, excessive consumption of diacid chloride, and formation of a sludge in the second solution which interferes with proper operation of the system. The problems, however, are readily obviated from continuously pumping the second solution through a molecular sieve, such as a natural or synthetic zeolite, which adsorbs water and HCl from the solution and also filters out any particles of suspended material or sludge.

In the above description we have stressed application of the invention to a system where the polymer formed in situ in the textile material is produced by the interfacial reaction of a diamine and a diacid chloride. In its broad aspect, the invention encompasses the utilization of any of the reaction systemsdisclosed in Patents 3,078,138, 3,084,018, 3,084,019 and 3,093,441where one of the reactants is a diamine and the other is a bifunctional compound capable of forming polymers with the diamine. Typical of these bifunctional compounds are diacid chlorides, bischloroformates, diisocyanates, and mixtures thereof. In cases where a diacid chloride is used, the polymer formed is a polyamide; Where a bischloroformate is used, the polymer is a polyurethane; Where a diisocyanate is used, the polymer is a polyurea. By using mixtures of bifunctional compounds, interpolymers may be produced. Typical of the last is the use of a diamine in conjunction with a mixture of a diacid chloride and a bischloroformate to produce a type of interpolymer which may be termed a copoly amide-urethane. Accordingly, in its board aspect the invention encompasses application of the critical factors described above in connection with any system for shrinkproofing which involves serial impregnation of a wool textile with 1) an aqueous diamine solution and then with (2) a solution of a bifunctional compound capable of forming a polymer with the diamine, said second solution having as its solvent an inert, essentially water-immiscible solvent. As noted above, typical of the bifunctional compounds which can be employed in the second solution are acid chlorides, bischloroformates, diisocyanates, and mixtures thereof. By applying these types of compounds in serial manner and in essentially mutually-immiscible phases, various types of polymers may be formed in situ on the wool fibers, rendering the textile shrinkproof. Typical examples of compounds which can be employed in a practice of the invention are described below.

As the diamine one may employ any of the aromatic, aliphatic, or heterocyclic compounds containing two primary or secondary amine groups, preferably separated by at least two carbon atoms. The diamines may be substituted if desired with various non-interfering (non-functional) substituents such as ether radicals, thioether radicals, tertiary amino groups, sulphone groups, fluorine atoms, etc. Typical compounds in this category are listed below merely by Way of illustration and not by Way of limitation: Ethylene diamine; trimethylene diamine; tetramethylene diamine; hexamethylene diamine; octamethylene diamine; decamethylene diamine; N,N' dimethyl-1, 3 propanediamine; 1,2 diamino Z-methylpropane; 2, 7 diamino 2,6 dimethyloctane; N,N'-dimethyl-1, 6- hexanediamine; 1,4 diamino cyclohexane; 1,4 bis(aminomethyl) cyclohexane; 2,2 diaminodiethyl ether; 2,2- diaminodiethyl sulphide; bis(4 aminocyclohexyl) methane; N,N' dimethyl 2,2,3,3,4,4 hexafiuoropentane- 1,5 diamine; ortho-, meta-, or para-phenylene diamine; benzidine; xylylene diamine; m-toluylene diamine; orthotolidine; piperazine, and the like. If desired, mixtures of different diamines may be used. It is generally preferred to use aliphatic alpha, omega diamines, particularly of the type wherein n has a value of 2 to 12, preferably 6 to 10. Particularly preferred is hexamethylene diamine, i.e., the compound of the above formula wherein 21:6.

As the diacid chloride one may employ any of the aliphatic, aromatic, or heterocyclic compounds containing two carbonylchloride (COCl) groups, preferably separated by at least two carbon atoms. The diacid chlorides may be substituted if desired with non-interfering (nonfunctional) substituents such as ether groups, thioether groups, sulphone groups, etc. Typical examples of compounds in this category are listed below merely by way of illustration and not limitation: Oxalyl chloride, maleylchloride, fumaryl chloride, malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimelyl chloride, suberyl chloride, azelayl chloride, sebacyl chloride, cyclohexane 1,4 biscarbonyl chloride, phthalyl chloride, isophthalyl chloride, terephthalyl chloride, 4,4'biphenyl-dicarbonyl chloride, ,B-hydromuconyl chloride, i.e., ClCOCH CH=CH-CH COCL diglycollic acid chloride, i.e., O(CH COCl) higher homologues of this compound as O(CH CH COCl) dithiodiglycollic acid chloride, diphenylolpropanediacetic acid chloride, i.e., (CH C(C H OCH COCI) and the like. If desired, mixtures of dilferent diacid chlorides may be used. It is also evident that the sulphur analogues of these compounds may be used and are included within the spirit of the invention. Thus, instead of using compounds containing two COC1 groups one may use compounds containing one CSC1 and one --COCl group or compounds containing two --CSC1 groups. Moreover, although the diacid chlorides are preferred as they are reactive and relatively inexpensive, the corresponding bromides and iodides may be used.

As the diacid chloride, it is generally preferred to use the aliphatic compounds containing two carbonylchloride groups in alpha, omega positions, particularly those of the type:

ClCO(CH COCl wherein n has a value from 2 to 12. Another preferred category includes the compounds of the formula (where A is the benzene or cyclohexane radical), especially para-substituted compounds such as terephthalyl and hexahydroterephthalyl chlorides.

As the bischloroformate one may use any of the aliphatic, aromatic, or heterocyclic compounds containing two chloroformate groups (-O-ii-Cl) preferably separated by at least two carbon atoms. The bischloroformates may be substituted if desired with noninterfering (non-functional) substituents such as sulphone groups, ether groups, thioether groups, etc. Typical examples of compounds in this category are listed below merely by way of illustration and not limitation: Ethylene glycol bischloroformate, diethylene glycol bischloroformate, 2,2-dimethyl propane 1,3-diol bischloroformate, propane-1,3-diol bischloroformate, butane-1,4-diol bischloroformate, hexane-1,6-diol bischloroformate, octane- 1,8-diol bischloroformate, decane-1,10-diol bischloroformate, butane-1,2-diol bischloroformate, hexane-1,2- diol bischloroformate, Z-methoxy-glycerol-l,3-bischloroformate, glycerol-1,2-bischloroformate, glycerol-l,3-bischloroforrnate, diglycerol bischloroformate, hexanetriol bischloroformate, pentaerythritol bischloroformate, cyclohexane 1,4 diol bischloroformate, hydroquinone bischloroformate, resorcinol bischlorofdrmate, catechol bischloroformate, bischloroformate of 2,2 bis(parahydroxyphenyl) propane, bischloroformate of 2,2-bis(parahydroxyphenyl) butane, bischloroformate of 4,4-dihydroxybenzophenone, bischloroformate of 1,2 bis(parahydroxyphenyl) ethane, naphthalene-1,5-diol bischloroformate, biphenyl-4,4'-diol bischloroformate, etc. If desired, mixtures of different bischloroformates may be used.

Among the preferred compounds are the aliphatic bischloroformates, for example, those of the type:

Ii ll C1CO-(CHz)nOCCl wherein n has a value from zero to 10. A useful category of aromatic bischloroformates are the bisphenol chloroformates, that is, compounds of the type:

wherein R-CR represents an aliphatic hydrocarbon group containing 1 to 12 carbon atoms and R is hydrogen or a low alkyl radical.

It is also evident that the sulphur analogues of the bischloroformates may be used and such are included within the spirit of the invention. Thus, instead of using the compounds containing two I] -OC-Gl groups one may use any of the compounds containing the sulphur analogues of these groups, for example, the compounds containing two groups of the formula wherein one X is sulphur and the other is oxygen or wherein both Xs are sulphur. Moreover, although the bischloroformates are preferred because they are reactive and relatively inexpensive, it is not essential that they contain chlorine and one may use the corresponding bisbromoformates or bisiodoformates.

As the diisocyanate one may employ any of the aliphatic, aromatic, or heterocyclic compounds containing two isocyanate (-NCO) groups, preferably separated by at least two carbon atoms. The diisocyanates may be substituted if desired with non-interfering (non-functional) substituents such as ether groups, thioether groups, sulphone groups, etc. Typical examples of compounds in this category are listed below merely by way of illustration and not limitation: Ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, cyclohexylene diisocyanate, =bis(2-isocyanatoethyl) ether, bis(2-isocyanatoethyl) ether of ethylene glycol, o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 3,3'-bitolylene-4,4-dliisocyanate, diphenyl ether-4,4-diisocyanate, 3,5,3',5' bixylylene-4,4- diisocyanate, diphenylmethane-4,4-diisocyanate, biphenylene diisocyanate, 3,3'-dimethoxy biphenylene-4,4'-diisocyanate, naphthalene diisocyanates, polymethyl polyphenyl isocyanates, etc. It is also evident that the sulphur analogues of these compounds may be used and such are included Within the spirit of the invention. Thus for example, instead of using the compounds containing two --NCO groups one may use their analogues containing either two -NCS groups or one NCO' group and one --NCS group. Another point to be made is that it is within the spirit of the invention to utilize the derivatives which yield the same products with compounds containing active hydrogen as do the isocyanates. Particular reference is made to the biscarbamyl chlorides which may be used in place of the diisocyanates. Thus one may use any of the above-designated compounds which contain carbamyl chloride groups (-N-gCl) or their sulphur analogues s (N- Cl) in place of the isocyanate groups.

Among the preferred compounds are the aliphatic diisocyanates, for example, those of the type wherein n has a value from 2 to 12. Other preferred compounds are the toluene diisocyanates, xylylene diisocyanates, and diphenylmethane-4,4-diisocyanate which may also be termed methylene-bis(p-phenylisocyanate).

Since the process of the invention makes use of an interfacial polymerization (formation of a polymer at the interface between mutually-immiscible phases of the individual reactants), it is evident that the polymer-forming agents need be applied in solutions wherein the solvents are substantially mutually immiscible. Thus the diamine reactant is applied in aqueous solution while the complementary reactant (diacid chloride, bischloroformate, or diisocyanate) is applied as a solution in an inert, essentially water-immiscible solvent, preferably one which is volatile, for example, benzene, carbon tetrachloride, toluene, xylene, ethylene dichloride, chloroform, hexane, octane, petroleum ether, or other volatile petroleum hydrocarbon mixture. It is generally preferred and the solution of the complementary reactant be dilute, that is, it should contain about /2 to preferably /2 to 2%, of the reactant. Generally, the conditions of treatment, such as the rate of traversal of the fabric, concentration of the reactants, degree of pressing, etc., are so correlated that the product contains about 0.25 to 3% of polymer.

Ordinarily, no reaction promoter other than the alkaline agents are required in the reactive solutions. However, one may add such agents as tertiary amines to the aqueous diamine solution. Other types of agents which may be added to the diamine solution or to the solution of the complementary reactant are tributyl tin chloride, stannous tartrate, ferric chloride, titanium tetrachloride, boron trifluoride-diethyl ether complex, or tin salts of fat acids such as tin laurate, myristate, etc.

To aid the diamine solution in penetrating into the textile, it is generally preferred to incorporate a minor proportion of a surface-active agent into this solution. For this purpose one may use such agents as sodium alkyl (C C sulphates, the sodium alkane (C C sulphonates, the sodium alkyl (C C benzene sulphonates,

esters of sulphosuccinic acid such as sodium dioctylsulphosuccinate, and soaps, typically sodium salts of fat acids. Surface-active agents of the non-ionic type may also be used and they have the desirable property of being non-substantive; that is, they are not preferentially absorbed by the wool. Typical examples of non-ionic agents are the reaction products of ethylene oxide with fatty acids, with polyhydric alcohols, with partial esters of fatty acids and polyhydric alcohols or with alkyl phenols, etc. Typical of such agents are a polyoxyethylene stearate containing about 20 oxyethylene groups per mole, a polyoxyethylene ether of sorbitan monolaurate containing about 16 oxyethylene groups per mole, a distearate of polyoxyethylene ether of sorbitol containing about 40 oxyethylene groups per mole, iso-octyl phenyl ether of polyethylene glycol, etc. A useful class of non-ionic agents are the nonylphenoxy polyethyleneoxy ethanols, containing 9 to 12 moles of ethylene oxide per mole of nonylphenol, as these compounds are readily soluble in the diamine solution even in the presence of relatively high concentrations of sodium carbonate. Generally, only a small proportion of surface-active agent is used, on the order of 0.05 to 0.2%, based on the weight of the solution. In addition to, or in place of the surface-active agent, a supplementary solvent may be added to the primary solvent (water) in quantity sufiicient to disperse the active reactant. For such purposes one may employ acetone, or other inert, volatile solvent, particularly one that is at least partially miscible with water.

In the foregoing description we have emphasized the utilization of our invention in connection with the shrinkproofing of wool. However, wool is by no means the only substrate which can be treated. In its broad aspect, the invention can be utilized in the treatment of any fibrous material, particularly when such material is in a state, e.g., a pre-yarn state, requiring further mechanical processing before end products such as yarn, fabrics, etc. are manufactured. Typical examples of such materials are animal hides; leather; animal hair; cotton; hemp; jute; ramie; linen; wood; paper; synthetic cellulosic fibers such as viscose, cellulose acetate, cellulose acetate-butyrate; casein fibers; polyvinyl alcohol-protein fibers; alginic fibers; glass fibers; asbestos; and organic non-cellulosic fibers such as poly(ethylene glycol terephthalate), polyacrylonitrile, polyethylene, polyvinyl chloride, polyvinylidene chloride, etc. Such applications of the teachings of the invention may be for the purposes of obtaining functional or decorative effects such as sizing, finishing, in-.

creasing gloss or transparency, increasing water-repellency, increasing adhesionor bonding-characteristics of the substrates with rubber, polyester resins, etc. The process of the invention is of special advantage as applied to hydrogen-donor textiles, for example, protein and cellulosic fibers, because these are especially adapted for chemical bonding of the resin to the fiber molecules The invention is further demonstrated by thefollowing illustrative example:

Shrinkage test."[he tests for shrinkage referred to below were conducted in the following manner: the knitted wool samples were washed in a reversing agitator-type household washing machine using a 3-p'0undlo'ad, a water temperature of F., and a low-sudsing detergent in a concentration of 0.1% in the wash liquor. .The wash cycle itself was for 75 minutes, followed by the usual rinses.

and spin drying. The damp material was then tumbledried in a household type clothes drier. The samples were then measured to determine their length and the shrinkage calculated from the original dimension. With a single wash by this method, samples of the control (untreated) fabric gave a length shrinkage of 40%.

Adhesion test.The tests for adhesion of one fiber to another in the strands of top were conducted as follows: a strand of the top, gripped between jaws spaced 10 inches part, was subjected to tension in a conventional testing instrument, the tension at the point where the strand breaks being recorded. The wide spacing of the jaws limits the measurement to adhesion between fibers and is independent of individual fiber strength since theaverage fiber-length was 2% inches and maximum fiberlength was 5 inches. With this test a lower rating indicates a desirable-Le, less mattedproduct. Without any treatment the top used as the raw material in the runs yielded a figure of 10 grams per grain per yard.

EXAMPLE A. In accordance with the invention The starting material in this run was fine wool top having a weight of 280 grains per yard. This material was continuously treated, using a system as shown in the drawing.

The bath in tank 3 was an aqueous solution containing 0.25% hexamethylene diamine, 0.6% of sodium metasilicate, and 0.05% of a sodium alkyl benzene sulphonate wetting agent. The pH of the solution was 12. During the run it was maintained at F.

The bath in tank 5 was a solution of 2% of sebacoyl chloride in an aliphatic petroleum solvent (Stoddard solvent).

The top was fed through the system at the rate of 8 yards per minute. By extending the path of the top within tank 3, the time of contact with the diamine solution was 30 seconds. After emergence from the diamine solution the top was pressed to a wet pick-up of 50-55%, and entered into the diacid chloride solution. Residence time in the latter solution was 5 seconds.

After the treated top had been washed, rinsed and dried, it was subjected to conventional operations to spin it into 2/20 yarns. Two ends of these yarns were then fed to a tubular knitting machine to fabricate sections of tubular knit material resembling the leg of a sock. The stitchlength was 0.8 inch, which represents a very loose construction with high shrinkage potential, The knit material was subjected to tests for shrinkage as described above. Also, samples of the dried top were tested for adhesion and during mechanical processing note was taken whether or not dusting occurred.

B. Comparative run (not in accordance with invention) In this run the same procedure as explained above was used with the following exceptions:

In the solution in tank 3 the concentration of hexamethylene diamine was 1%. The sodium metasilicate was replaced by sodium carbonate in an amount suflicient to give the solution a pH of 11.0.

The treated top was subjected to the same operations and tests as described in Part A.

The results are tabulated below:

(C) subjecting it to mechanical working to produce yarns. 2. The process of claim 1 wherein the said monomeric bifunctional organic compound is a diacid chloride.

3. The process of claim 1 wherein the wool in a preyarn condition is Wool top and wherein the monomeric bifunctional organic compound is a diacid chloride.

1 The amount of dusting during spinning of the treated top was rated on the basis: 0=no dusting; 10=extreme dusting.

Having thus described the invention, what is claimed is: 1. A process for manufacturing wool products of reduced shrinkage upon washing, which comprises- (A) subjecting wool in a pre-yarn condition to serial impregnation with (a) an aqueous solution containing from 0.1 to 0.3% of a monomeric diamine, the pH of said solution being adjusted to a level of at least 12. to 12.5 by the addition of a strongly-alkaline material, (b) and then with a solution of a monomeric bifunctional organic compound capable of forming a polymer with said diamine, said compound being dissolved in an inert, volatile, water-immiscible solvent, (B) washing and drying the so-treated wool, and

No references cited.

GEORGE F. LESMES, Primary Examiner J. CANNON, Assistant Examiner US. Cl. X.R.

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