US3542505A - Treatment of textiles with aziridine-modified polyurethanes - Google Patents

Description

United States Patent 3,542,505 TREATMENT OF TEXTILES WITH AZIRIDINE.

MODIFIED POLYURETHANES Allen G. Pittman, El Cerrito, and William L. Wasley, Berkeley, Calif, assiguors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed Oct. 13, 1967, Ser. No. 675,038 Int. Cl. D06m 13/48 U.S. Cl. 8127.6 '14 Claims ABSTRACT OF THE DISCLOSURE Polyurethanes containing isocyanate groups are reacted with alkylene imines to prepare aziridine-modified polyurethanes useful for application to textile materials to improve their properties, e.g., to impart shrink resistance and durable press qualities. Typical example: A polyether polyurethane containing free NCO groups is reacted with ethylene imine to yield an aziridine-modified polymer which is formed into an emulsion and applied to a textile material. The treated textile may be directly cured or the curing operation may be delayed until the fabric is manufactured into a finished garment, the latter system being preferred to attain permanent creases.

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 sublicenses 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 provision of novel processes for treating textile materials and the products of such processes. A special object of the invention is the provision of such treatments involving the use of aziridine-modified polyurethanes whereby to provide such benefits as improved shrinkage resistance and permanent press qualities. Further objects and advantages of the invention will be evident from the following description wherein parts and percentages are by weight unless. otherwise specified.

The prior artadiscloses that various aziridine derivatives have beenQproposed for use as shrinkproofing agents for W001. See Tesoro, U.S. Pats. 3,165,375 and 3,279,882, and Textile Research Journal, June 1964, pp. 523-532. Among the aziridines tested by said investigator were certain so-called amino-aziridines (those in which the nitrogen atom of the aziridine rings is an amino nitrogen) and amido-aziridines (those in which the nitrogen atom of the aziridine rings is an amido nitrogen). It is reported by this investigator that eifectiveness of the aziridines as shrinkproofing agents is related to the basicity of the ring nitrogens, so that the aminoaziridines provide good shrinkproofing results while the amido aziridines do not. In fact, Pat. 3,179,882 discloses that etfective shrinkproofing results are obtained with the amio aziridines only when they are applied conjointly with a polyamine (i.e., a basic compound). Further advantages attributed to the amido aziridines by the said investigator are that they stiffen the treated fabric and cause severe losses in abrasion resistance (Text. Res. Jour., June 1964, p. 529).

We have found that a novel class of aziridine derivatives exhibits an unusual ability to improve the properties of textiles, particularly wool. Our agents are not only chemically distinct from those of the prior art, but also obviate the problems analyzed above. Some of the significant advantages provided by our aziridine deriva tives are listed below:

They provide elfective shrinkproofing even when applied in small proportions to the textile material.

They are effective per se; the conjoint application of a polyamine is unnecessary. It may be noted in this connection that application of polyamines to wool is hazardous because if any unreacted polyamine remains on the wool it will cause yellowing and degradation of the fibers.

They do not adversely aifect the abrasion resistance of the textile material. In fact, the treated material often exhibits increased abrasion resistance. In contrast, the amido aziridines studied by Tesoro are admitted to cause decrease in abrasion resistance.

They do not cause a stiffening of the fabric. This is in sharp contrast to Tesoros findings that effective shrinkproofing is coupled with stilfening; indeed, that the degree of stiffening is proportional to shrinkproofing efficiency. See Text. Res. Jour., June 1964, p. 529.

They do not affect the intrinsic properties of the fibers, such as color, tensile strength, flexibility, hand, porosity, etc. so that the treated fibrous materials can be em ployed in any of the usual textile applications as in fabricating shirts, skirts, trousers, and other garments.

They provide flat-setting and durable crease qualities.

The aziridines of the invention are particularly useful in applications involving delayed curing, that is, where the aziridine is applied to the fabric, the treated fabric is manufactured into a garment provided with appropriate creases in selected areas, and the garment is then subjected to a curing treatment so that the completed garment is not only shrink resistant but also press-free, i.e., it can be subjected to repeated washings without requiring pressing to maintain the creases. The particular ad vantages of the present invention which make them especially adapted to such use are: Our aziridines do not undergo spontaneous curing; they remain in the uncured state even after long storage of the treated fabric. The aziridines remain in the uncured state even if subjected to moisture at ordinary temperatures. Thus, the treated fabrics may be subjected to moist conditions as may be required in certain garment fabrication steps without premature curing and without decomposition of the applied aziridine.

The aziridines of theinvention may aptly be described as aziridine-modified polyurethanes, and have the structure:

I u 9 0 NHR-NH-d- I L I R, arm" n wherein:

A is the residue of a polyether polyol or polyester polyol having a valence of n,

R is a hydrocarbon radical containing at least two can bon atoms,

R is hydrogen, halogen, lower alkoxy, or a radical of the structure R" is hydrogen or a lower alkyl radical, n is an integer from 2 to 10, and x is an integer from 1 to 2..

The aziridine derivatives of the invention are prepared by reacting an alkylene imine, such as ethylene, propylene, or butylene imine, with a polyether (or polyester) polyurethane containing free isocyanate groups. This simple reaction establishes the desired aziridine-modfiication for padding and insulation applications, and in the proof the starting polymer. A typical, but by no means least two free NCO groups per polymer molecule. Prelimiting, example of the synthesis is illustrated below: ferred are the polymer intermediates having a molecular ([JH; (EH3 f H Isoeyanate-terminated ooN NH-iI-OTCHzCHzCHzOH2O7CNH NCO Wyeth Wlyurethane 2CH2-CH2 Ethylene imine ([3113 (3H3 CE; H (l) /CH2 l N- NH NH( 1-O CH2CHzCHa- CHrO}-CNH NHC-N C a m Hz Azlrldine-modified polyether polyurethane (In the above formulas, m represents the number of Weight of at least 500, more preferably those having a tetramethyleneether repeating units. This may range, for 25 molecular weight of at least 1000. Also, it is generally example, about from 5 to 50.) preferred to use the polyether-based polymers, for ex- The reaction is carried out at about to 40 C., ample,-the NCO-containing polyurethane derived from and under essentially anhydrous conditions to avoid hypolyalkylene ether glycols such as polyethylene ether drolysis of the isocyanate groups. The alkylene imine glycols,-polytrimethylene ether glycols, polytetramethylene is supplied in excess to ensure conversion of all isocyanate ether glycols, polypropyleneether glycols and the like.

groups to aziridine groups. It is evident from the for- THE POLYMER INTERMEDIATES mulas above that modification in the aziridine rings can be effected by selection of the alkylene imine reactant. Polyether p y polyurethanes containing free For example, if propylene imine i d i t d f h l. isocyanate groups useful as intermediates for the present ene imine, the aziridine rings will be of the structure invention y bfi P p as Well known in the aft, y reacting a polyether (or polyester) polyol with a 2 polytsocyanate, using an excess of the latter to ensure provision of free isocyanate groups in the product. A cH, typical, but by no means limiting, example is illustrated H below:

HO CHzCHzCHPCHz-O Polyether polyol 2 N C O Polylsocyanate NCO (IJHa (3113 (R f fi Isocynate-terminated ooN NH-d-o om-om-om-oHt-o c-NH NCO Pmymthm In other words, in this case R" (in Formula I) is 0 (In the above formulas m represents the number of methyl. tetramethyleneether repeating units. This may range, for

Referring to Formula I, above, it is evident that selecexample, about from 5 to 50.) tion of the polymer intermediatethe polyether or poly- Representative examples of polyisocyanates which may ester polyurethane containing free isocyanate groups be employed for reaction with the polyether (or polywill determine the values of A, R, R, n, and x. The prepester) polyol include: aration of these intermediates is well known in the art;

they are widely used in the production of urethane foams toluenenzA-dnsocyanate toluene-2,6-diisocyanate commercial mixtures of toluene-2,4 and 2,6-diisocyanates ethylene diisocyanate ethylidene diisocyanate propylene-1,2 diisocyanate duction of elastomers. Although the preparation of these intermediates forms no part of the present invention, this subject will be explained below to illustrate the wide range of intermediates Which may be employed l h x lene-1,2-diisoeyanate in producing the aziridine derivatives of the invention. cyclohexylene-1,4-diis0cyanate Thus, for the purposes of the invention, the intermediate m-phenylene diisocyanate may be any polyether polyurethane which contains at 3,3'-diphenyl-4,4-biphenylene diisocyanate 4,4-biphenylene diisocyanate 3,3'-dichloro-4,4-biphenylene diisocyanate 1,6-hexamethylenediisocyanate 1,4-tetramethylene-diisocyanate l,10-decamethylenediisocyanate 1,S-naphthalenediisocyanate cumene-2,4-diisocyanate 4-methoxyl ,3 -phenylenediisocyanate 4-chloro-1,3-phenylenediisocyanate 4-bromo-l,3-phenylenediisocyanate 4-ethoxy-l,3-phenylenediisocyanate 2!,4-diisocyanatodiphenylether 5,6-dimethyl-l,3-phenylenediisocyanate 2,4-dirnethyl-l,3-phenylenediisocyanate 4,4'-diisocyanatodiphenylether benzidinediisocyanate 4,6-dimethyl-l,3-phenylenediisocyanate 9,10-anthracenediisocyanate 4,4-diisocyanatodibenzyl 3,3-dimethyl-4,4'-diisocyanatodiphenylmethane 2,6-dimethyl-4,4-diisocyanatodiphenyl 2,4-diisocyanatostilbene 3,3-dimethyl-4,4'-diisocyanatodiphenyl 3,3'-dimethoxy-4,4'-diisocyanatodiphenyl 1,4-anthracenediisocyanate 2,5-fluorenediisocyanate 1,8-naphthalenediisocyanate 2,6-diisocyanatobenzfuran 2,4,6toluenetriisocyanate, and p,p',p"-triphenylmethane triisocyanate.

It is evident that the selection of the polyisocyanate reactant will determine the values of R and R in Formula I. For example, where the reactant is a hydrocarbon diisocyanate, R will be a hydrocarbon radical and R will represent a hydrogen atom forming part of said hydrocarbon radical. Where the reactant contains a substituent such as chlorine or methoxy-as would be the case with, for example, 4-chloro-l,3-phenylene diisocyanate or 4- methoxy-l,3-phenylene diisocyanate-R will be the hydrocarbon residue of the reactant and R will be the substituentchlorine or methoxy in the given examples.

The polymer intermediates useful for the purposes of the invention may, in turn, be derived from any of a wide variety of polyether polyols and polyester polyols, and representative examples of these polyols are described below:

Among the polyether polyols which may be so used are those prepared by reaction of an alkylene oxide with an initiator containing active hydrogen groups, a typical example of the initiator being a polyhydric alcohol such as ethylene glycol. The reaction is usually carried out in the presence of either an acidic or basic catalyst. Examples of alkylene oxides which may be employed in the synthesis include ethylene oxide, propylene oxide, any of the isomeric butylene oxides, and mixtures of two or more diiferent alkylene oxides such as mixtures of ethylene and propylene oxides. The resulting polymers contain a polyether backbone and are terminated by hydroxyl groups. The number of hydroxyl groups per polymer molecule is determined by the functionality of the active hydrogen initiator. For example, a difunctional alcohol such as ethylene glycol (as the active hydrogen initiator) leads to polyether chains in which there are two hydroxyl groups per polymer molecule. When polymerization of the oxide is carried out in the presence of glycerol, a trifunctional alcohol, the resulting polyether molecules contain an average of three hydroxyl groups per molecule. Even higher functionalitymore hydroxyl groupsis obtained when the oxide is polymerized in the presence of such polyols as pentaerythritol, sorbitol, dipentaerythritol, and the like. In addition to those listed above, other examples of polyhydric alcohols which may be reacted with alkylene oxides to produce useful polyether polyols include:

propylene glycol trimethylene glycol 1,2-butylene glycol 1,3-butanediol 1,4-butanediol 1,5-pentanediol 1,2-hexylene glycol 1, l0-decanediol 1,2-cyclohexanediol 2-butene-1,4diol 3-cyclohexene-1,l-dimethanol 4-methyl-3-cyclohexene-1,l-dimethanol B-methylene-1,5-pentanediol diethylene glycol (Z-hydroxyethoxy -1-propanol 4- (Z-hydroxyethoxy) -1-butanol 5- Z-hydroxypropoxy) l-pentanol 1- (2-hydr0xymethoxy) -2-hexanol I-(Z-hydroxypropoxy)-2-octanol 3-a1lyloxy-1,5-pentanedio1 2-allyloxymethyl-Z-methyl-1,3-propanediol (4-pentyloxy) methyl] 1 ,3-propanediol 3-(o-propenylphenoxy) 1,2-propanediol thiodiglycol 2,2- [thiobis (ethyleneoxy) diethanol polyethyleneether glycol (molecular weight about 200) 2,2-isopropylidenebis (p-phenyleneoxy) diethanol 1,2,6-hexanetriol l,l,l-trimethylolpropane 3- (2-hydroxyethoxy) -1,2-propanediol 3-(Z-hydroxypropoxy)-1,2-propanediol 2,4-dimethyl-2- (Z-hydroxyethoxy) methylpentanediol-1,5

1,1, l-tris[ (Z-hydroxyethoxy) methyl] ethane 1,1,1-tris (Z-hydroxypropoxy methyl] propane triethanolamine triisopropanolamine resorcinol pyrogallol phloroglucinol hydroq-uinone 4,6-di-tertiarybutyl catechol catechol orcinol methylphloroglucinol hexylresorcinol 3-hydroxy-2-naphthol 2-hydroxy-l-naphthol 2,5-dihydroxy-l-naphthol bis-phenols such as 2,2-bis-(p-hydroxyphenyl)propane and bis-(p-hydroxyphenyl) methane 1, 1,2-tris- (hydroxyphenyl) ethane 1,1,3-tris-(hydroxyphenyDpropane.

An especially useful category oi polyether polyols are the polytetramethylene glycols. They are prepared by the ring-opening polymerization of tetrahydrofuran, and contain the repeating unit.

in the polymer backbone. Termination of the polymer chains is by hydroxyl groups.

The polyester polyols which may be employed as precursors for the aziridines of the invention, are most readily prepared by condensation polymerization of a polyol with a polybasic acid. The polyol and acid reactants are used in such proportion that essentially all the acid groups are esterified and the resulting chain of ester units is terminated by hydroxyl groups. Representative examples of polybasic acids for producing these polymers are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, thapsic acid, maleic acid, fumaric acid, glutaconic acid, a-hydromuconic acid, fi-hydromuconic acid, a-butyl-u-ethylglutaric acid, a,p-diethylsuccinic acid, 0- phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, mellophanicacid, prehnitic acid, pyromellitic acid, citric acid, benzenepentacarboxylc acid, l,4-cyclohexanedicarboxylic acid, diglycollic acid, thiodiglycollic acid, dimerized oleic acid, dimerized linoleic acid, and the like. Representative examples of polyols for forming these polymers includes ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, butene-l,4-diol, 1,5-pentane diol, 1,4-pentane diol, 1,3-pentane diol, 1,6-hexane diol, hexene-1,6-diol, 1,7-heptane diol, diethylene glycol, glycerine, trimethylol propane, 1,3,6-hexanetriol, triethanolamine, pentaerythrtiol, sorbitol, and any of the other polyols listed hereinabove in connection with the preparation of polyether polyols.

An interesting class of polyester polyols are those which include polyether units so that they may be considered as polyester polyols or as polyether polyols, depending on whether the ester or the ether groups are in majority. The compounds may be produced by the condensation polymerization of any of the above-mentioned polybasic carboxylic acids with a polyalkyleneether glycoltypically, a polyethyleneether glycol having a molecular weight of about 200 to 2000-using the glycol in the require proportion to assure termination by hydroxyl.

Esters of the hydroxyl-co'ntaining acid, ricinoleic acid, form another category of useful polyester polyols. Typically, one can use esters of ricinoleic acid with ethylene glycol, propylene glycol, glycerol, pentaerythritol, diglycerol, dipentaerythritol, polyalkyleneether glycols, and the like. Representative of this category of polyester polyols is castor oil which is composed mainly of the tri-glyceride of ricinoleic acid.

APPLICATION OF THE AZIRIDINE TO THE TEXTILE The aziridines of the invention may be applied to the textile in various ways. One technique involves applying the aziridine as such to the textile, using warming if necessary to make the aziridine flow, and distributing it with calender rolls or the like. A preferred technique involves dissolving the aziridine in an inert, volatile solvent and applying the resulting solution to the textile material. Typical of the solvents which may be used are benzene, toluene, xylene, dioxane, diisopropyl ether, dibutyl ether, butyl acetate, chlorinated hydrocarbons such as chloroform, carbon tetrachloride, ethylene dichloride, trichloroethylene, 1,3-dichlorobenzene, fiuorohydrocarbons such as benzotrifiuoride, 1,3 bis-(trifiuoromethyl)benzene, etc., petroleum distillates such as petroleum naphthas, etc. Usually it is preferred to use the aziridines in the form of aqueous emulsions. These can be prepared by customary techniquesagitation of the aziridine with water and a conventional emusifying agent such as an alkylphenoxypoly-(ethyleneoxy)ethanol, polyoxyethylene sorbitan monopalmitate, polyoxyethylene lauryl ether, polyoxyethylene-polyoxypropylene stearate, sorbitan monopalmitate, I

sorbitan monolaurate, and the like. The concentration of the aziridine in the dispersionthis last term being herein employed in a generic sense to include solutions and emulsins-is not critical and may be varied depending on such circumstances as the solubility characteristics of aziridine, the amount of aziridine to be deposited on the fibers, the viscosity of the dispersion, etc. In general, a practical range of concentration would be from about 1% to about The dispersion may be distributed on the textile material by any of the usual methods, for example, by spraying, brushing, padding, dipping, etc. A preferred technique involves immersing the textile in the dispersion and then passing it through squeeze rolls to remove the excess of liquid. Such techniques as blowing air through the treated textile may be employed to reduce the amount of liquid which exists in interstices between fibrous elements. In any case, the conditions of application are so adjusted that the textile material contains the proportion of aziridine desired. Generally, the amount of aziridine is about from 0.5 to 20%, based on the weight of the textile ma- 8 terial but it is obvious that higher proportions may be used for special purposes. In treating textiles such as fabrics the amount of aziridine is usually limited to a range of about 0.5 to 10% to attain the desired end such as shrink resistance without interference with the hand of the textile.

After application of the aziridine, the treated textile is cured (heated) to effect an insolubilization ofthe applled aziridine and to promote bonding of the azirine to the textile. Although the mechanism of bonding has not been identified, bonding is known to occur and it is believed to involve chemical combination of the aziridlne w th active radicals present in the textile substrate, these act ve radicals including carboxyl, hydroxyl, amino, and th ol groups. Such groups are, of course, present in many textile materials including wool, animal hair, leather, and other proteinaceous materials; cotton, rayon, linen, and other cellulosic fibers, nylon, polyurethanes, and many other syntheic fibers.

In cases where the aziridine is applied as a dlspersion, that is, a solution, emulsion, or suspension, the solvent or other volatile dispersing medium is preferably evaporated prior to the curing operation. Such prior evaporation is not a critical step and the evaporation may be simply effected as part of the curing step. The temperature applied in the curing step is not critical and usually is within the range from about 50 C. to about 150 It is obvious that the time required for the curing will vary with such factors as the reactivity of the selected aziridine, the type of textile material, and particularly the temperature so that a lower curing temperature Wlli require a longer curing time and vice versa. It will be further obvious to those skilled in the art that in any particular case the temperature of curing should not be so high as to cause degradation of the textile or the azlridme. In many cases an adequate cure is elTected by heatlng the treated textile in an oven at about C. for about 5 to 60 minutes.

Although the present invention is of particular advantage in its application to wool, this is by no means the only type of fiber which comes into the ambit of the invention. Generically, the invention is applicable to the treatment of any textile material and this material may be in any physical form, e.g., bulk fibers, filaments, yarns, threads, slivers, roving, top, webbing, cord, tapes, woven or knitted fabrics, felts or other non-woven fabrics, garments or garment parts. Illustrative examples of textile materials to which the invention may be applied are: Polysaccharide-containing textiles, for instance, those formed of or containing cellulose or regenerated celluloses, e.g., cotton, linen, hemp, jute, ramie, sisal, cellulose acetate rayons, cellulose acetate-butyrate rayons, saponified acetate rayons, viscose rayons, cuprammonium rayons, ethyl cellulose, fibers prepared from amylose, algins, or pectins; mixtures of two or more of such polysaccharide-containing textiles. Protein-containing textiles, for instance, those formed of or containing wool, silk, animal hair, mohair, leather, fur, regenerated protein fibers such as those prepared from casein, soybeans, peanut protein, zein, gluten, egg albumin, collagen, or keratins, such as feathers, animal hoof or horn. Mixtures of any two of more protein-containing textiles. Mixtures of polysaccharide-containing textiles and protein-containing textiles, e.g., blends of wool and cotton; wool and viscose, etc. Textiles formed of or containing synthetic resins, e.g., alkyd resins, polyvinyl alcohol, partially esterified or partially etheri-fied polyvinyl alcohol, nylon, polyurethanes, polyethylene glycol terephthalate, polyacrylonitrile, polyethylene, polypropylene, polyvinyl chloride, and polyvinylidene iodine chloride. Blends of natural fibers such as cotton or Wool with synthetic fibers such as nylon, polyethyleneglycol terephthalate, acrylonitrile, etc. Inorganic fibers such as asbestos and glass fibers. The applications of the teachings of the invention may be for the purposes of obtaining functional or decorative effects such as shrinkproofing, developing permanent crease qualities, sizing, finishing, increasing abrasion resistance, increasing gloss or transparency, increasing water-, oil-, and soil-repellency, increasing adhesion or bonding characteristics of the substrates with rubber, polyetser resins, etc.

DELAYED CURE SYSTEM A particular embodiment of this invention is concerned with the production of wool products which exhibit not only shrink resistance but also permanent press qualities. Heretofore, no one has been able to impart this combination of useful properties to wool. Existing wool shrinkproofing treatments do lead to dimensionally-stable fabrics; however, when the fabrics are washed or drycleaned they have a mussy appearance and must be pressed. Creases have been set in woolen garments by, for example, treatment with reducing agents such as ammonium thioglycollate or sodium bisulphite. The creases, however, do not withstand aqueous laundering nor generally more than 1 or 2 dry-cleanings. Of course, no shrinkproofing is attained with these creasing procedures. Attempts to combine wool shrinkage treatments with creasing treatments have not been successful in that although shrinkage can be controlled, creases are lost after aqueous laundering and the fabrics need ironing for neat appearance. Various materials such as melamine-formaldehyde resins, urea-formaldehyde resins, dihydroxy-ethylene dimethylol urea, or alkyl carbamates, which are commercially used in producing permanently creased garments of cotton or cotton-synthetic blends have proved entirely unsuccessful when applied to wool.

However, these problems are obviated by the present invention. By application of our aziridines to wool fabrics one attains resistance to shrinkage, a smooth wrinkle-free appearance after washing or dry-cleaning so that no ironing is required, and creases and pleats imparted to the fabric are permanent-they withstand repeated aqueous laundering or non-aqueous dry-cleaning.

This embodiment of the invention is most profitably practiced in a system which incorporates a delayed cure, that is, the aziridine is applied to the fabric but curing is delayed until the fabric has been made up into the desired product which may be, for example, a completed garment. The curing then not only bonds the aziridine to the fabric, but also renders permanent the creases or pleats which have been imparted to the fabric. Typical ways of practicing this embodiment of the invention are described in detail below:

The aziridine is applied to the fabric using a solution or emulsion of the aziridine, as described hereinabove. The conditions of application may be adjusted to vary the amount of aziridine deposited on the fabric. Usually, it is preferred to deposit about 0.2 to 20% of the aziridine, based on the weight of the fabric. In a preferred modification of the procedure a reducing agent, such as sodium bisulphite, is incorporated in the liquid preparation of the aziridine. However, as hereinafter explained the reducing agent may be applied at a later stage in the process. The treated fabric is then dried to remove the solvent or other carrier in which the aziridine was dispersed for the application step. The drying may be in air at ordinary (room) temperature, or, warm air may be applied to increase the rate of evaporation. To avoid premature curing, the temperature of the treated fabric should be kept below about 50 C. However, since curing does not occur immediately, short exposures to higher temperatures are permissible.

The fabric containing the aziridine in its uncured state is then made up into the desired product. This may be, for example, a garment, in which case the fabric would be subjected to the usual garment-making operations of cutting, sewing, and pressing. Included in these operations would be formation of creases or pleats in selected areas by the usual pressing methods employed by the tailor. In the event that a reducing agent was not coapplied with theaziridine, then a reducing agent may be applied to the textile during the moistening step which commonly forms a part of the pressing operation. For example, an aqueous solution of the reducing agent may be sprayed on the textile, particularly in those areas where it is intended to form creases or pleats. Enough of the solution is usually applied so there is about 0.1 to 2% of the reducing agent, based on the weight of fabric. It is to be particularly emphasized that the production of garments need not follow directly after the aziridine treatment of the fabric. Indeed, the fabric containing the uncured aziridine can be held for long periods without danger of spontaneous curing. The aziridines of the invention are particularly characterized by their stability, i.e. their ability to remain in an uncured state for long periods of time. Moreover, their stability is not affected by moisture. If moisture is applied (as necessary in certain garment fabricating steps) there is no danger of premature curing.

The garment or other textile article is then subjected to a curing operation to insolubilize the aziridine and bond it to the wool fibers. Typically, the curing is accomplished by placing the garments in an oven where they are maintained at a temperature and for a time sufiicient to cause the desired curing of the applied aziridine. In general, temperatures of at least 50 C., preferably about -150 C., are applied for period of about 5-60 minutes. The product after removal from the oven is now ready for use or for sale and, as previously noted, exhibits not only resistance to shrinkage when washed but also retains its pleats, creases, or other conformations imparted to the garment. Also, when washed, the products retain a neat appearance free from wrinkling or mussiness so that they are truly press-free, i.e., no pressing is needed even after repeated washings.

As noted hereinabove, where permanent crease qualities are desired, a reducing agent is preferably applied to the textile, concomitantly with application of the aziridine or in a later step but prior to curing. Representative examples of reducing agents include: Inorganic sulphides such as alkali metal, alkaline earth metal, ammonuim, etc. sulphides and hydrosulphides. Organic compounds containing a thiol group, as, for example, thioglycollic acid, or its salts such as the alkali metal or ammonium salts; beta-mercapto ethanol; monthio glycerol; dithio-glycerol; butyl mercaptan; thiomalic acid or its salts; thio-lactic acid or its salts; thiophenol; thiocresol; etc. Formamidine sulphinic acid, also known as iminoaminomethane sulphinic acid betaine. Formaldehyde sulphoxylates, generally used in the form of their alkali metalwzinc, or ammonium salts. Alkali metal or ammonium sulphites, bisulphites and hydrosulphites. Aldehyde or ketone adddition products with sulphites or bisulphites, e.g., sodium formaldehyde bisulphite, sodium acetone bisulphite, etc. Generically, the reducing agents used in accordance with the invention may be defined as sulphur-containing, reductive, disulphide-splitting agents because of the fact that they all contain sulphur in their structures and because they have the ability to open the disulphide (cysine) linkage in the wool molecule, generally converting a single disulphide (--SS) bond into two thiol (-SH) groups.

The amount of reducing agent is not critical and may be varied depending on such circumstances as the eflicacy of the agent selected, the durability of set desired in the product, the character of the fibers being treated, etc. Even minute amounts of the reducing agent will provide some degree of improvement. Usually, the reducing agent is used in an amount from about (1L1 to about 2%, based on the weight of the textile substrate being treated. It is, of course, obvious that the reducing agent should not be applied in such a high proporion as would degrade the textile substrate.

Although the use of a reducing agent in conjunction with our aziridines is primarily of advantage in treat- 1 1 ments where the substrate is to be provided with durable creases or other configurations, it is within the broad ambit to employ the reducing agent in other procedures, e.g., ones wherein creasing is not involved. The advantage of the reducing agent is that it enhances bonding of the aziridine to the textile substrate. Thus, generically, the invention includes in is broad compass any textile-treating procedure wherein the reducing agent is used in conjuncton with our aziridines, and is appled to the textile concomitantly with the aziridine or at any earlier or later stage, prior ot the curing step.

EXAMPLES The invention is further demonstrated by the following illustrative examples.

Washing procedure for shrinkage tests: The samples were washed in a reversing agitator-type household washing machine, using a three-pound load, a water temperature of 105 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 from the washer was then tumble-dried in a household-type clothes dryer. The dried samples were measured to determine their length nad width and the shrinkage calculated from the original dimensions.

Example 1.Preparation of aziridine-modified polytetramethyleneether polyurethane (fHs (EH:

This indicated preparation of the desired aziridine derivative.

(B) To a IOO-gram sample of the aziridine solution, prepared as described above, was added 4 grams of a commercial oil-soluble emulsifying agent, an alkylphenoxypoly(ethyleneoxy)ethanol. The mixture was stirred rapidly and cc. of water were slowly added. The thick waterin-oil emulsion was transferred to a blender and an additional 200 cc. of water was added while stirring at high speed. The resulting oil-in-water emulsion of the aziridine was used as a stock supply and diluted with water as needed.

Example 2.---Application of aziridine-modified polytetramethyleneether polyurethane The emulsion prepared as described above in Example 1 was diluted with water (to levels indicated below) and applied to swatches of wool. In some instances, measured amounts of NaHSO were added to the emulsions.

The treatments in each case were as follows: Wool swatches were immersed in the emulsion bath until completely wet-out, then the swatches were run through a squeeze roll to attain a wet-pick-up of 80100%, based on the weight of the fabric. The damp fabrics were dried in air at room temperature.

Next, the dried fabrics were creased: Each swatch was moistened by spraying with water, folded, and then subjected to steaming and pressing on a tailors hot-head press. The fabrics were steamed for 10-20 seconds, then pressure (-80 p.s.i.) and heat (ca. 140l50 C.) applied for 20 seconds. The creased swatches were then cured in a forced draft oven at 300 F. for 20 minutes.

The cured swatches were then given three 75-minute washes (as described above) and tumble-dried after each wash. The swatches were measured for shrinkage and examined for crease retention and over-all appearance after each tumble drying (following each wash).

In a first series of runs, applied to an undyed woolen fabric, the following results were obtained:

TABLE I 1st washing and drying 2nd washing and drying 3rd washing and drying Area Area Area Cone. of aziridine in treating shrinkage, shrinkage, shrinkage, emulsion, percent percent Appearance percent Appearance percent Appearance 4 0.8 E 0. 5 E 0.5 E 3 2. 1 G 1. 6 F 2. 4 P 2 2. 0 G 1. 5 F 2. 0 P 2 (plus 1% NaHSOa). 2. 3 E 2.0 E 2. 7 E None (untreated wool 18. 1 48. 3

*Fabric appearance was rated as follows:

Excellent (E) =sharp crease, fabric flat and in no need of ironing. Good (G) =sharp crease, fabric fiat but could use slight touching up with the iron. Fair (F) =crease still visible but not sharp, some wrinkling, needs definite ironing;

Poor (P) =no crease visible, badly wrinkled.

wherein A represents the residue of a polytetramethyleneether glycol containing about twenty-five units.

(A) Two hundred grams (0.1 mole) of the poly- 1st washing and drying 2nd washing and drying 3rd washing and drying Area Area Area Cone. of aziridine in treating shrinkage, shrinkage, shrinkage, emulsion, percent percent Appearance percent Appearance percent Appearance 4 2.8 E 1. E 2. 2 G 3 3. 2 E 3. 2 G 5. 2 F 2 (plus 3% NaHSOa)--- 3. 5 E 2. 0 E 3.0 E None (untreated wool) 46. 6 59. 7

*Fabrie appearance was rated as described in Table I:

Example 3.Examination of treated fabrics at intervals for delayed-cure features The emulsion prepared as described in Example 1 was diluted to an aziridine concentration of 2%. In one of the runs,the diluted emulsion per se was used; in a second run spectrum of the solution revealed no residual NCO groups. 2% of NaHSO was added.

Wool fabric was treated as follows: Swatches of the wool were wet-out in the emulsion bath, pressed to 80- 100% wet pick-u and air-dried at room temperature. The dried fabrics were then stored at room temperature, and after certain times of storage (3, 8, 1.5, and 30 days) were creased and cured as described in Example 2. The swatches were then subjected to four 75-minute washes with tumble-drying after each wash. The results are tabulated below:

TABLE III Properties, aiter 4th washing Time of storage before setting Bisulphlte in Area and curing, emulsion shrinkage, days bath percent Appearanee 2.1 E 2.1 G 2.2 E 2.0 G 1.8 E 2.0 G 2.2 E 2.3 E 4 28. 3

1 Appearance was rated as described in Table I. 1 In this run, the re-moistening of the fabric (part of the creasing operagimfiwsagaecomplished by spraying with an aqueous solution containing a s. g Untreated wool. After 2 washes.

OCN

Example 4 The starting material for this synthesis was a com* mercial liquid polyether polyurethane having a molecular weight of about 850 and an isocyanate (-NCO) content of about 9.5%. It is believed to have the structure wherein A represents the residue of polytetramethyleneether glycol containing about seven One hundred grams (0.12 mole) of the liquid poly urethane was dissolved in 300 ml. of dry benzene. While stirring, 13 ml. (0.26 mole) of ethylene imine was added at a rate slow enough that the reaction temperature did not rise above 40 C.

An emulsion containing 3% of the aziridine-modified polyurethane was prepared as follows: To 47 grams of the solution of the aziridine polymer, prepared as described above, was added 1 gram of a commercial emulsifier, tris(polyoxyethylene)sorbitan monopalmitate, and 450 ml. of water and applying rapid agitation in a blender. More dilute emulsions were prepared by incorporating water in this stock emulsion.

Samples of wool flannel were treated with the emulsions by padding with the emulsion, squeezing through rollers to remove excess liquid, and then curing in an oven for 20 minutes at 300 F.

The treated samples were then tested for shrink resist ance, using the Accelerotor method. In this test the fabric samples are milled at 1700 r.p.m. for 2 minutes at 40-42 C. in an Accelerotor with aqueous sodium oleate (0.5%) solution, using a liquor-to-Wool ratio of 50 to 1. After this washing operation, the samples were measured to determine their area and the shrinkage calculated from the original area. This is a very severe test which applied to untreated wool samples gives an area shrinkage of 40-50%. The Accelerotor is described in American Dyestufl Reporter, vol. 45, p. 685, Sept. 10, 1956.

The results obtained are tabulated below.

The starting material for the synthesis was a commercial liquid polyether polyurethane having a molecular weight of about 1300 and an isocyanate (NCO) content of 6.5%. It is believed to have the structure O LNH NCO ea. 13

One hundred grams (0.077 mole) of the liquid poly urethane was dissolved in 200 grams of dry benzene. To this solution was added 7 grams (0.16 mole) of ethylene imine at a rate slow enough so that the temperature of the reaction mixture did not rise about 35 C. Five minutes after the last of the ethylene imine had been added, the LR. spectrum of the reaction mixture showed that no free NCO was present.

Emulsions were prepared of the aziridine-modified polyurethane, and these were applied to wool flannel, and tested for shrinkage, all as described above in Example 4. The results are tabulated below.

Concentration of aziridine- Area shrinkage modified polyurethane in (Accelerotor test) emulsion, percent: percent 3 None (control) 42 Example 6 CH-CH:

Fifty grams of the aziridine-modified polymer-having a molecular weight of 6300-6800 and containing 0.36 to 0.38 milliequivalents of imine per gram of polymer-was dissolved in 50 grams of benzene and '2 grams of a commercial emulsifier, a polyoxyethylene-polyoxypropylene 15 monostearate, was added. While stirring the solution in a blender, water was gradually added to make 1000 grams of an emulsion.

this the samples were measured for shrinkage and assayed for retention of creases and general appearance. The results obtained are tabulated below:

Properties after three 75-min. washes *Appearanco was rated as described in Table I.

A sample of wool flannel was immersed in the emulsion for 1 minute, then passed through squeeze rollers, 1

and then dried in air. From the increase in weight of the fabric the uptake of polymer was found to be 4%. The treated fabric was cured (300 F., 10 minutes), then tested for shrinkage by the Accelerotor method described above. Area shrinkage was found to be 1%. A Sample of the same fabric but untreated shrank 39.7% in area by the same test.

Example 7 A series of experiments were carried out to compare the effectiveness of the aziridine derivatives of the invention with that of various commercial products recommended for shrinkproofing applications. The various products tested were:

(A) The aziridine-modified polyalkyleneether polyurethane described above in Example 1. It was applied in the form of 2% emulsion to which had been added sodium bisulphite (1% (B) A polyamide modified by reaction with epichlorhydrin. This material is commercially available as a water-soluble resin (Kymene manufactured by Hercules Co.) and contains epoxide linkages available for reaction with wool and for cross-linking. This product was applied in form of a 2.5% solution in water, afid to which was added sodium bisulphite (1% (C) A polyacrylate containing methylol groups (CH OH) which can cross-link and/or react with hydroxy groups in wool by elimination of water. The main component of the polymer is a soft acrylate, polybutyl acrylate. It is sold under the name HA-8 by Rohm and Haas Co. for wool shrinkproofing and other uses. It was used with an acid catalyst, ZnNO in accordance with the manufacturers recommendation. It was applied in the form of a 4% emulsion, to which was added sodium bisulphite (1% (D) A urea-formaldehyde condensation product, consisting basically of dihydroxyethylene dimethylol urea:

It is widely used in applications to cotton and other cellulosic textiles to impart permanent press qualities. It was used, following the manufacturers recommendation in conjunction with an acid catalyst, ZnNO It was applied in the form of 10% aqueous solution to which was also added 1% sodium bisulphite.

Samples of a wool fabric were treated with the various agents described above, using the following technique in each case. The fabric was wet-out in the aqueous solution or emulsion of the agent, put through squeeze rolls to 80-100% wet pick-up, and dried in air overnight. The next day the samples were moistened by spraying with water and were creased by folding and application of steam and pressure. The creased samples were then cured in an oven3l0 F. for minutes.

The cured samples were then subjected to three 75- minute washes with tumble drying after each wash. After Example 8 Experiments were carried out to compare the effectiveness of the process of the invention with one wherein a commercially-employed shrinkproofing treatment was followed by treatment with sodium bisulphite.

A sample of undyed worsted (wool) fabric was given a shrinkproofing treatment by application of polyhexamethylene sebacamide through interfacial polymerization, as disclosed in Pat. 3,078,138. In particular, the fabric was first immersed in an aqueous solution of hexamethylene diamine (1.5%) and sodium carbonate (1.5%), run through squeeze rolls, then immersed in a solution of sebacoyl chloride (2.0%) in a volatile petroleum hydrocarbon solvent, run through squeeze rolls, and washed in water to remove unreacted materials, and dried. The fabric was then wet-out with an aqueous 2% solution of sodium bisulphite and creased by folding and application of steam and pressure, as described in Example 2. The treated fabric was then subjected to a -minute wash, as described above, and tumble dried. It was observed that the crease had disappeared. In contrast, a sample of the same fabric treated as described in Example 2 with a 2% emulsion of the aziridine-modified polyurethane and 1% sodium bisulphite, retained its creases even after four 75-minute washes (each followed by tumble drying). This unusual durability of the creases plainly indicates that our process involves a synergistic effect between the aziridine-modified polyurethane and the bisulphite.

Example 9 A hydroxy-terminated polyethylene adipate of molecular weight approximately 6500 was end-capped by reaction with an excess of toluene diisocyanate to produce a polyether polyurethane with terminal NCO groups. One mole of this polymer was then reacted with two moles of ethylene imine to produce an aziridine-terminated polyether polyurethane. A 2% emulsion of this aziridine-modified polymer was prepared as in Example 1, part (B), and wool fabric was treated with the emulsion as described in Example 2. After four 75-minute washes the treated fabric showed 3% shrinkage in the warp and 2% shrinkage in the fill directions, while the control (untreated wool fabric) had shrunk 30% in the warp and 24% in the fill under the same washing conditions.

Having thus described our invention, we claim:

1. A process of treating textile material to improve its properties which comprises depositing on the textile material an aziridine-modified polyurethane of the structure I CHR" wherein:

A is the residue of a polyether polyol or polyester polyol having a valence of n,

R is a hydrocarbon radical containing at least two carbon atoms,

CHR

R" is hydrogen or a lower alkyl radical,

n is an integer from 2 to 10, and

x is an integer from 1 to 2.

2. The process of claim 1 wherein A is the residue of a polyalkyleneether glycol and n is 2.

3. The process of claim 1 wherein is the tolylene radical.

4. The process of claim 1 wherein the textile material is wool.

5. The process of claim 1 wherein a sulphur-containing reductive disulphide-splitting agent is deposited on the textile material.

6. The process of claim 1 wherein the textile material containing the deposited aziridine-modified polyurethane is subjected to garment-fabricating operations including cutting, sewing, and pressing, and the fabricated garment is cured to insolubilize the aziridine-modified polyurethane in situ to provide a press-free garment wherein imparted creases are unaffected by repeated washing of the garment.

7. The process of claim 6 wherein a sulphur-containing reductive disulphide-splitting agent is deposited on the textile material prior to curing.

8. Textile material carrying a deposit of an aziridinemodified polyurethane of the structure wherein:

R is hydrogen, halogen, lower alkoxy, or a radical of the structure CHR R is hydrogen or a lower alkyl radical,

n is an integer from 2 to 10, and

x is an integer from 1 to 2.

9. The product of claim 8 wherein A is the residue of a polyalkyleneether glycol and n is 2.

10. The product of claim 8 wherein R l h is the tolylene radical.

11. The product of claim 8 wherein the textile material is wool.

12. The product of claim 8 wherein said deposit is cured in situ on the textile material.

13. The product of claim 8 wherein said deposit is cured in situ on the textile material and in the presence of a sulphur containing reductive disulphide splitting agent.

14. The product of claim 13 wherein said agent is an alkali metal bisulphite.

References Cited UNITED STATES PATENTS 2,327,760 8/1943 Bestian et al 81l6 2,881,046 4/1959 Rose et a1 8-l27.6 2,891,877 6/1959 Chance et al. 8-127.6 3,279,882 10/ 1966 Tesoro 8l27.6 3,285,798 11/ 1966 Tesoro 2602 X 3,300,274 1/1967 Pittman et al 8-1276 3,454,671 7/1969 Oertel 26077.5 X

DONALD LEVY, Primary Examiner C. E. VAN HORN, Assistant Examiner US. Cl. X.R.