US3519383A - Minimizing odor by adding methylol amides and methylol amines to reducing agent solutions used to treat wool - Google Patents

Description

United States Patent 3,519,383 MINIIVHZING ODOR BY ADDXNG METHYLUL AMIDES AND METHYLGL AMINES T0 RE- DUCING AGENT SOLUTEGNS USED T l) TREAT W091,

Earl Peters, Spartanbnrg, S.C.., assignor to Bearing Milliken Research Corporation, Spartanburg, S.C., a corporation of Delaware No Drawing. Continuation of application Ser. No.

283,565, May 27, 1963. This application Aug. 27, 1968, Ser. No. 764,008

Int. Cl. D06rn 3/06, 3/08 US. Cl. 8-127.6 Claims ABSTRACT OF THE DISCLOSURE Formaldehyde and formaldehyde-generating compounds are used in the modification of keratinic fibers with reducing agents to inhibit fiber odor.

This application is a continuation of application Ser. No. 283,565, filed May 27, 1963 and now abandoned.

This invention relates to processes for eliminating the odor associated with keratin fibers which have been treated with reducing agents and to keratin fibers resulting from such processes.

Fabrics containing keratin fibers, particularly wool fabrics, have been treated with reducing agents for the purpose of setting the fabrics in a given configuration. Wool fabrics treated with reducing agents can, for example, be set in a creased configuration which is substantially durable to wetting. This treatment has been utilized to improve fabrics containing wool fibers in many ways, e.g., to impart durable creases, pleats, and/or fiat configurations to wool fabrics, to impart to these fabrics a propensity for such setting operations, to elasticize wool fabrics and for many other purposes.

Fabrics treated with reducing agents, however, have a characteristic, unpleasant odor. The cause of the odor is unknown. It is not believed to be related to the sulfur content of many reducing agents utilized in the above processes since reducing agents which contain no sulfur atoms cause the same unpleasant odor. It is believed that the odor is merely characteristic of wool which has been treated with a reducing agent whereby disulfide linkages in the wool fiber are reduced to the sulfhydryl form. These sulfhydryl groups are generally believed to be oxidized during subsequent setting operations, although the fact thereof and the mechanism of the oxidation reaction has given rise to a number of conflicting theories.

Regardless of the mechanism of the reaction of keratin fibers with reducing agents, however, the end product invariably is characterized by an unpleasant odor.

Many attempts have been made to solve this problem, particularly since processes which utilize reducing agents to improve properties of fabrics containing keratin fibers have enjoyed increasing commercial success. A typical technique involves the use of masking agents on reduced wool fabrics. These agents mask the reduced wool odor, but often impart to the fabrics so-treated an odor which purchasers do not associate with normal wool. Consequently, the fabric containing the masking agent is nearly as objectionable in odor as the untreated reduced wool fabric. Furthermore, these masking agents often are not durable to conventional dry-cleaning techniques. It is particularly desirable that the reduced wool fabric be indistinguishable in odor from fabrics which have not been treated with reducing agents.

The odor problem associated with processes involving the use of reducing agents for modification of keratin fibers has been solved in accordance with this invention 3,519,383 Patented July 7, 1970 by contacting reduced keratin fibers, having the characteristic unpleasant odor, with an aldehyde compound. The aldehyde may be applied as such or by way of an aldehyde-generating compound which, upon heating or chemical activation, generates the desired aldehyde.

Formaldehyde and formaldehyde generators are the most readily available aldehydes and are preferred for use in accordance with this invention. When the aldehyde is applied to finished fabric, i.e., fabric which has undergone textile finishing operations, it is preferred that the aldehyde be derived from linear formaldehyde polymers, such as paraformaldehyde, which depolymerize upon heating to provide monomeric formaldehyde vapors. The fabric is exposed to the vapors of the depolymerizing polymer in this embodiment of the invention. The vapors have little or deleterious effect on the fabric finish.

Typical aldehydes other than formaldehyde include saturated aliphatic aldehydes, such as acetaldehyde, propionaldehyde, butylaldehyde, isobutylaldehyde, valeraldehyde, isovaleraldehyde, caproaldehyde, enanthaldehyde, caprylaldehyde, pelargonaldehyde, capraldehyde, lauraldehyde, palmitic aldehyde, stearaldehyde and the like; unsaturated aliphatic aldehydes, such as acrolein, crotonaldehyde, tiglic aldehyde, citronellal, citral, propiolaldehyde and the like; alicyclic monofunctional aldehydes, such as formylcyclohexane and the like; aliphatic dialdehydes, such as glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, maldealdehyde and the like; substituted aldehydes, such as chloral, aldol and the like; aromatic aldehydes wherein the aldehyde group is attached to a ring, such as benzaldehyde, phenylacetaldehyde, ptolualdehyde, p-isopropylbenzaldehyde, o-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, pnitrobenzaldehyde, salicylaldehyde, anisaldehyde, vanillin, veratraldehyde, piperonal, u-naphthaldehyde, anthraldehyde and the like; and aromatic aldehydes wherein the aldehyde group is not attached to a ring, such as phenylacetaldehyde, cinnamaldehyde and the like; and heterocyclic aldehydes, such as ot-formylthiophene, a-formylfurfural, furfural, tetrahydrofurfural and the like.

Typical aldehyde generating compounds include linear polymers, particularly those of the general formula HO (CH O) -H which depolymerize to monomeric formaldehyde gas upon vaporization. In this class of compounds, there are included lower polyoxymethylene glycols, wherein n is from about 2 to about 8; paraformaldehyde, wherein n ranges from about 6 to about 100; alphapolyoxymethylenes, wherein n is greater than about 100; beta-polyoxymethylene wherein n is greater than about 100 and a trace of H is present, and the like.

Polyoxymethylene glycol derivatives may also be utilized, e.g., such as the polyoxymethylene diacetates, the lower polyoxymethylene dimethyl ethers, gamma-polyoxymethylenes (higher polyoxymethylene dimethyl ethers), delta-polyoxymethylenes, epsilon-polyoxymethylenes and the like. In general, higher temperatures, e.g., up to about 200 C. are utilized to effect depolymerization of these derivatives. In many instances, depolymerization, with formaldehyde generation, is most readily effected by treatment with dilute alkali or acid to produce the corresponding glycol which can then be hydrolyzed to formaldehyde solution.

Formaldehyde acetate (formals) may also be utilized. Preferred formals are produced by reaction of formaldehyde with alcohols of the formula CH (OR) in the presence of an acid catalyst, wherein R is alkyl or aralkyl. These compounds hydrolyze to formaldehyde and the parent alcohol. Preferred formals include methylol and 1,3-dioxolane. The latter compound hydrolyzes to formaldehyde and ethylene glycol and is particularly preferred among this class of compounds when used in presensitizing processes.

Additional suitable generating compounds include the various methylol compounds, for example, methylolalkanolamine sulfites, such as N-methylolethanolamine sulfite, N,N-dimethylolethanolamine sulfite, N,N-dimethylolisopropanolamine sulfite and the like; methylol amides, such as N-methylolformamide, N-methylolacetamide, N-methylolacrylamide and the like; amines, such as hexamethylene tetramine, trimethylolmelamine and the like; and compounds such as the alkali-metal formaldehyde bisulfites, including sodium and potassium formaldehyde bisulfites.

The above compounds may be utilized to eliminate the characteristic odor of keratin fibers which have been treated with any conventional reducing agents utilized for setting keratin fibers.

These reducing agents, which are well known in the art, include the metallic formaldehyde sulfoxylates, such as zinc formaldehyde sulfoxylate; alkali metal sulfoxylates, such as sodium formaldehyde sulfoxylate; alkali metal borohydrides, such as sodium borohydride and potassium borohydride; alkali metal sulfites, such as sodium or potassium bisulfite, sulfite, metabisulfite, or hydrosulfite; mercaptan acids, such as thioglycollic acid and its water-solu ble salts such as sodium, potassium, or ammonium thioglycollate; mercaptans, such as hydrogen sulfide and sodiurn or potassium hydrosulfide; alkyl mercaptans, such as butyl or butyl or ethyl mercaptans and mercaptan glycols, such as beta-mercaptoethanol; ammonium bisulfite, sodium sulfide, sodium hydrosulfide, cysteine hydrochloride, sodium hypophosphite, sodium thiosulfate, sodium dithionate, titanous chloride, sulfurous acid and the like and mixtures of these reducing agents.

In practice, these reducing agents are applied to fabrics containing keratin fibers, after which the fabric is set in a durable configuration, e.g., creased, pleated and/or flat,

by means of heat and/or pressure. In a typical durable creasing operation, a solution of the desired reducing agent is sprayed to about 40% pickup onto the fabric just prior to pressing, after which the wet fabric is pressed on a Hoffman press. After drying in the creased configuration, the fabric crease is durable to subsequent wetting.

Fabrics may be treated with reducing agents at the mill level to impart thereto a propensity for subsequent durable setting. These treatments have become known as presensitizing processes, whereby the fabric is presensitized for subsequent durable setting. There are presently two types of presensitizing processes, namely, the type which requires that water be sprayed onto the fabric prior to the setting operation and the type wherein water is not required. The former type process is known as a wet crease presensitizing process, the latter being known as a dry crease process.

In a wet crease process, the fabric is impregnated with reducing agent at the mill level, after which it is dried and given a finish under mild conditions, generally involving low temperatures. The fabric is then shipped, cut into garments, sprayed with water to about 40% pickup, pressed on a Hoffman press and dried in the pressed configuration.

Dry crease processes have been provided by addition to the fabric at the mill level a low molecular weight polyhydroxy compound or a swelling agent as set forth in U.S. patent applications Ser. Nos. 167,420, now Pat. No. 3,423,166 and 111,447, now abandoned, respectively. In these processes, the additive is incorporated in the fabric along with the desired reducing agent. For some reason, unexplained to date, the resulting fabric can be dried at higher temperatures without destroying the presensitization characteristics. More importantly, however, the resulting fabric can be set in a desired configuration without adding large amounts of water to the fabric. For that matter, no extraneous water whatsoever need be added beyond the regain level of the fabric to obtain excellent, durable configurations.

By the term low molecular weight polyhydroxy compound is meant a compound containing more than one hydroxy group and preferably having a molecular weight no greater than about 4000. Of these compounds, the

most readily available and desirable compound, from the standpoint of ease of application, comprises ethylene glycol. A particularly preferred group of glycols includes the polyfunctional glycols having terminal hydroxyl groups separated by 2 to 10 methylene groups, including, of course, the preferred ethylene glycol as well as trimethylene glycol, tetramethylene glycol, pentmethylene glycol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, and decamethylene glycol, or such glycols as 1,2-propylene glycol, dipropylene glycol, 1,3-butylene glycol, diethylene glycol, polyethylene glycol or the like.

Polyfunctional compounds containing more than 2 hydroxyl groups include the polyfunctional alcohol glycerols such as glycerine, quintenyl glycerin, diethylglycerol and mesicerin, as Well as trimethylol ethane, trimethylol butane, tris(hydroxymethyl)aminomethane and others. Glycol ethers, such as the water-soluble or dispersi'ble polyethylene glycols or polypropylene glycols having molecular Weights no greater than about 4000 also provide satisfactory results when utilized in accordance with this invention.

Urea constitues the most readily available and desirable swelling agent, although any other material which will swell wool fibers in aqueous medium is suitable. For example, guanadine compounds such as the hydrochloride; formamide, N,N-dimethylformamide, acetamide, thiourea, phenol, lithium salts, such as the chloride, bromide and iodide and the like are similarly useful.

The swelling agent or low molecular weight polyhydroxy compound may be utilized in any desired amount depending on requirements for particular fabrics. For example, as little as about 0.5 to about 1% of the additives, based on the weight of the fabric, provides some improvement, although, in general, larger amounts, e.g., from about 3 to about 10% by weight provide noticeable improvement. Larger amounts of up to about 50% or higher may be utilized, of course, if the particular end use justifies the increased chemical cost in the use of these additives.

The above processes have been improved so that presensitized fabrics having desirably lustrous finishes can be provided. In this novel type process, described in U.S. patent application Ser. No. 278,359, now U.S. Pat. No. 3,449,061, the fabric is impregnated with a reducing agent precursor compound, finished by conventional mill finishing operations, and then exposed to a gaseous re ducing agent activator. In this manner, all wet procedures are conducted prior to application of the desired finish on the fabric. The finish is substantially retained since the gaseous activator does not disturb the finish. Furthermore, the keratin fibers of the fabric are not in a reduced state until after all finishing operations have been completed, so that no extraordinary care must be taken to avoid inducing high residual relaxation shrinkage properties into the fabric.

Also, since the fabric is not presensitized until after exposure to the gaseous activator chemical, full finishing operations can be practiced to impart a high degree of finish to the fabric with no effect whatsoever on the degree of presensitization.

It has also been discovered that fabrics produced in this manner can be durably set without the addition of water prior to pressing. This property is obtained without the aid of additives such as set forth above, although slightly improved results can be obtained if these additives are utilized.

By reducing agent precursor as utilized herein is meant a chemical compound which forms a reducing agent for keratin fibers upon reaction with another chemical compound. It is generally preferred that the precursor compound have a pH of about 7 or greater as a 1% solution in water. Particularly suitable compounds include lower alkanolamines, such as monoethanolamine, diethanolamine, triethanolamine, N-methyl ethanolamine, N-

ethyl ethanolamine, N,N-dimethyl ethanolamine, N,N- diethy ethanolamine, N,N-diisopropyl ethanolamine, N- aminoethyl ethanolamine, N-methyl diethanolamine, npropanolamine, isopropanolamine, triisopropanolamine, n-butanolarnine, dimethylbutanolamine, dimethylhexanolamine, polyglycolamines of the general formula HO(C H O) RNH wherein x is a positive integer and R is alkyl, e.g., the compound where x=2 and *R=C H and the like. These compounds readily form reducing agent compounds upon exposure to S0 gas and other activators.

While the above alkanolamines constitute the preferred embodiment of the reducing agent precursor compounds, additional compounds include other amines, for example those characterized by the formula R(NH wherein x is a positive integer of from 1 to about 4 and R is alkyl (e.g., ethylamine, hexylamine and the like); aryl (e.g., aniline, toluidines, benzidine, and the like); R 'ONH wherein x=l, and R is alkyl or aryl, (e.g., hydrazides, such as acetoyl hydrazide H CCONHNH butyrohydrazide, benzoylhydrazide, and the like); hydrazin'es of the formula R"NHNH wherein R is selected from hydrogen, alkyl, aryl, and the like; e.g., hydrazine, methylhydrazine, phenylhydrazine and the like; piperazine compounds, such as piperazine, homopiperazine, N-methyl piperazine, N-hydr0xyethyl piperazine, N-aminoethyl piperazine, N-phenyl piperazine and the like.

Additional suitable basic precursor compounds include alkalis, such as the alkali-earth metal and alkali-metal compounds, including the hydroxides, carbonates, borates, phosphates, e.g., sodium hydroxide, potassium hydroxide, lithium hydroxide, strontium hydroxide, barium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium borate, potassium borate, sodium perborate, disodium monohydrogen phosphate and the like.

Additional reducing agent precursor chemicals include aldehydes, particularly formaldehyde and glyoxal, although other aldehydes are suitable, e.g., saturated aliphatic adlehydes containing up to about 18 carbon atoms, such as acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, enanthaldehyde, nonaldehyde, palmitic aldehyde and the like; unsaturated aliphatic aldehydes, such as acrolein, crotonaldehyde, tiglic aldehyde, citral, propiolaldehyde and the like; alicyclic monofunctional aldehydes, such as formylcyclohexane and the like; aliphatic dialdehydes, such as glyoxal, pyruvaldehyde, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde and the like; aromatic aldehydes, such as benzaldehyde, tolualdehyde, a-tolualdehyde, cinnam aldehyde, salicylaldehyde, anisaldehyde, phenylacetaldehyde, a-naphthaldehyde, anthraldehyde, pyrocatechualdehyde, veratraldehyde and the like; heterocyclic aldehydes, such as a-formylthiophene, a-formylfuran, and the like; dialdehyde starch, and other aldehyde carbohydrates and aldehydic cellulosic materials. These aldehydes are consumed in the reaction with the reducing agent activator gas so that, for odor removal, it is necessary to add an amount in excess of that which is consumed when one of these aldehydes is used as a reducing agent precursor.

It has also been discovered that ammonia per se can be utilized as a reducing agent precursor, e.g., in combination with S0 or N 0 activator gases. Ammonia may be provided as a gas, preferably anyhydrous, or as ammonium hydroxide, methylammonium hydroxide, ethylammonium hydroxide and similar compounds. When applied as a gas, it may be applied before, after or during the desired finishing operation.

The procedure of applying the ammonia to the fabric after finishing, and before or after application of the activator gas is highly preferred for its simplicity and for the excellent results which are obtained Without a wet finishing operation, which involves the added expense of padding and drying. In addition, ammonia gas may be utilized in combination with other reducing agent precursors. For example, a wool fabric can be impregnated With an alkanolamine, finished, and then exposed to both ammonia and S0 gases. This technique provides particularly excellent presensitization in that better creases, or other configurations, of improved durability can be accomplished in this manner.

On the other hand, ammonia may be utilized as a reducing agent activator per se, particularly in combination with nitrites to form ammonium nitrites, ammonium complexes and the like.

As noted above, the reducing agent precursor, except for ammonia gas, is preferably applied to the fabric prior to finishing in that these compounds are most conveniently applied to the fabric in liquid media which would substantially destroy the finish on the fabric. Most of the precursors are soluble in water and can be applied to the fabric as aqueous solutions, although dispersions, emulsions and other systems are suitable. Uniform impregnation of the fabric is readily accomplished by conventional techniques, such as padding, spraying and the like. It should be appreciated, however, that the precursor chemical may be applied in gaseous form before or after finishing if the practitioner prefers to volatilize the normally liquid precursor systems.

By reducing agent activator as utilized herein is meant a chemical compound, preferably in a gaseous state, which can react with one of the above reducing agent precursors to form a different chemical compound which is a reducing agent for keratin fibers, i.e., is capable of rupturing the disulfide bonds of the keratin fiber molecular structure. It is not known with certitude if a reducing agent per se is formed in situ on the keratin fibers being treated, although the formation thereof is highly probable since both precursor and activator are consumed during the treatment and cannot be washed out of the fabric in their pre-treatment form.

Most of the preferred activator gases are reducing agents for keratin fibers and it is possible that the pretreatment of the fibers with one of the precursor chemicals may merely sensitize the fibers for more efficient reaction of the keratin fibers with the reducing agent gas, whereby presensitization of the fibers for subsequent durable setting is effected.

Regardless of the mechanism of the presensitization, however, the reducing agent precursor chemicals and the reducing agent activator gases can react in the absence of keratin fibers to form different reducing agent compounds. Furthermore, presensitization is effected by the process of this invention where treatment with a reducing agent per se is essentially ineffective for such purpose. For example, excellent presensitization of keratin fibers for subsequent durable setting in the absence of large amounts of water is effected by the process of this invention wherein the fabric is first impregnated with monoisopropanolamine, subjected to the desired finishing operation and then exposed to S0 possibly to produce monoisopropanolamine sulfite in situ on the fabric. On the other hand, if monoisopropanolarnine sulfite per se is utilized, no such presensitization is effected and a durable crease could only be obtained by pressing the fabric while it is wet with large quantities of water, e.g., on the order of 40% by weight or more. Similarly, treatment with S0 gas alone is generally ineffective in producing a fabric presensitized for subsequent durable setting, with or without large amounts of water.

Since sulfites are generally excellent reducing agents for keratin fibers, S0 is a highly preferred reducing agent activator gas. Other suitable activator gases include, however, hydrogen sulfide; mercaptans, such as methyl mercaptan (B.P. 6 C.), ethyl mercaptan (B.P. 37 C.) and the like; mercaptan alcohols, such as Z-mercaptoethanol (B.P. 5052 C. at 10 mm. Hg) and the like; nitrogen oxides, such as N 0 and the like; phosphorus-containing gases, such as phosphine and the like; nitrosating agents, such as NOCl, NOBr and the like.

The amount of reducing agent precursor and activator gas can be readily determined by one skilled in the art depending on the fabric being treated and the extent of presensitization desired.

The preferred precursor chemicals are fairly strong bases. Keratin fibers tend to degrade considerably during prolonged storage under basic conditions. It is preferred, therefore, that a sulficient amount of the reducing agent activator gas, which generally is acidic, be utilized for substantially complete reaction with the precursor chemical or until substantially neutral fabric is produced. Obviously, the fabric may be shipped under slightly acidic or basic conditions, or even under highly acidic or basic conditions, but the optimum degree of physical properties in combination with the presensitized characteristic is obtained when the fabric is shipped essentially neutral.

In this regard, the fabric treated in accordance with this invention has a higher degree of creasability after prolonged storage than fabrics treated by previous techniques. In fact, the performance of the fabric after storage is generally superior to the performance immediately after gassing. Consequently, conventional storage time has become an asset rather than a liability in the present presensitizing technique.

Fabric containing the precursor chemical may be exposed to the gaseous activator in conventional equipment. For example, steam boxes, decating apparatus, beam and package dye machines, drying ovens and the like may be utilized.

The aldehyde compounds of the present invention may be applied to fabrics treated by any of the above processes, before, during or after such processes. In general, the amount of aldehyde compound utilized will be determined by the type fabric treated, the degree of reduction produced by reducing agent treatment and the stage of the various processes at which the aldehyde compound is applied. For example, if the fabric has been finally set in a desired configuration or presensitization toward subsequent setting is not desired, an amount of aldehyde compound should be applied to the fabric which eliminates the reduced keratin fiber odor. In this regard, an excess of aldehyde compound may be utilized if desired and the excess removed by heating and/or washing the fabric.

Since there is no readily available technique for measuring the degree of reduction of disulfide linkages of the keratin fibers treated with reducing agent, there is no clear way to prescribe what amount of aldehyde compound should be added. Consequently, subjective tests are utilized. In the embodiment of the invention wherein previously set fabrics are treated, the fabric can be tested for odor after the odor removal treatment is given. If an odor remains, additional aldehyde compound is applied. If the reduced keratin fiber odor is eliminated, but an aldehydic odor remains, the fabric may be heated or washed to remove the residual aldehydic odor without reinstituting the reduced keratin fiber odor. This, of course, indicates that some reaction has taken place and that this reaction is substantially irreversible even under conditions of heat and pressure.

A different problem arises when presensitization toward subsequent durable setting is desired, since the odoreliminators of this invention also destroy presensitization. The best test for amount of aldehyde compound to be utilized again is subjective. For example, the aldehyde compound may be added to the fabric along with the presensitizing chemicals. After completion of the process, swatches of the fabric may be tested for creasability and odor. The creasing test may be made with or without water depending on the type process being practiced. If better than the desired level of creasing is obtained and a moderate reduced keratin fiber odor remains, additional aldehyde compound may be applied to the fabric. Conversely, if the crease performance is not as high as desired, less aldehyde compound should be utilized. In

either instance, the fabric can be re-run through one of the presensitizing processes without deleterious effects. In the former instance, an aldehyde or generator thereof may be applied to the fabric without re-running it through the process.

While the above subjective tests are the types that invariably will be utilized for specific situations, some indication can be given as to the amount of aldehyde that should be utilized. Presensitization toward subsequent durable setting has been produced when there is utilized from about 1 to about mole percent, most preferably from about 5 to about 20 mole percent, of the aldehyde compound, based on the moles of reducing agent which are utilized in the treatment of the keratin fibers. In the gas type presensitizing process, the aldehyde may be based on the theoretical number of moles of reducing agent which would be produced in situ from the amounts of reducing agent precursor and activator compounds which are utilized.

In any event, the above subjective tests should be utilized to devise process limitations for specific fabric, reducing agent and equipment conditions.

While the process of this invention is particularly adapted to fabrics composed essentially of keratin fibers, particularly those composed entirely of wool fibers, it is also applicable to fabrics wherein synthetic, natural, or other keratin fibers are blended with the wool component. Other keratin fibers include mohair, alpaca, cashmere, vicuna, guanaco, camels hair, llama and the like. Preferred synthetic fibers for blending with these fibers include polyamides, such as polyhexamethylene adipamide; polyesters, such as polyethylene terephthalate; and acrylic fibers, such as acrylonitrile homopolymers or copolymers containing at least about 85% combined acrylonitrile, such as acrylonitrile/methyl acrylate (85/15), and cellulosics, such as cellulose acetate and viscose rayon. Of the natural fibers which may be blended With the keratin fibers, cotton is preferred.

Furthermore, the fibers need not be in fabric form during treatment. For example, the process may be conducted on top, tow, roving, sliver, yarn and the like.

The process of this invention may be performed on woven, non-woven, or knitted fabrics of any type, dyed or undyed.

In the following examples, dry crease performance data are obtained from presensitized fabric samples having dimensions of 4 /2 inches in the filling direction by 6 inches in the warp direction. These samples are folded in half with the fold parallel to the warp yarns. The samples are then placed on a Hoifman press, the cover is closed and locked and the samples are pressed with 30 seconds top steam and 30 seconds baking, followed by 10 seconds vacuuming.

The creased samples are then opened and placed in a standing water bath which contains a wetting agent and is heated to F. After 30 minutes the samples are removed, folded along the original crease line and allowed to air dry. After drying, the creases remaining in the samples are rated subjectively by at least three observers, the crease ratings runing from 1 (no appreciable crease) to 5 (very sharp crease).

EXAMPLE I The following aqueous pad solutions are prepared:

(A) 5 monoethanolamine sulfite+0.1% Synowet HR anionic Wetting agent.

(B) 10% monoethanolamine sulfite+0.1% Synowet I-IR anionic wetting agent.

(C) 12.8% monoethanolamine sulfite+0.1% Synowet HR anionic wetting agent.

(D) 12.8% monoisopropanolamine sulfite+0.1% Synowet HR anionic wetting agent.

(E) 12.8% monoisopropanolamine su1fite+20% ethylene glycol+0.l% Synowet HR anionic wetting agent.

Samples of an all wool fabric, Deering Milliken style number 8012 worsted fabric, are padded with each of these solutions to the levels shown in Table I. After drying in a relaxed condition on a Fleissner dryer, the fabric samples are creased after wetting to 40% by weight with water as set forth above to provide crease ratings as shown in Table I.

The creases of all the fabrics treated herein display excellent durability to wetting at 170 F. In addition, however, each fabric sample has the odor of reduced wool.

To remove this objectionable odor, each sample is hung in a closed container over a 37% formaldehyde solution. The solution is heated to 5060 C. and maintained at that temperature for two hours. Upon removal from the formaldehyde vapor-laden container, the samples are entirely devoid of the characteristic reduced wool odor.

In addition the relaxation shrinkage of the fabric samples which are exposed to formaldehyde vapors is substantially less than before exposure to formaldehyde. For example, the fabric sample treated with solution A above, before pressing, has a relaxation shrinkage of 3.9% in the warp direction and 2.6% in the filling direction. After exposure to formaldehyde vapors, the corresponding values are 0.2 and 0.3%, respectively.

In another typical embodiment, the fabric treated by solution E, after pressing and without formaldehyde exposure, has warp and filling relaxation shrinkage values of 4.0 and 3.8%, respectively. After formaldehyde exposure, these values are 1.9 and 2.0%, respectively.

Similarly, trouser legs made from the fabric treated by solution B have warp and filling relaxation shrinkage values reduced to 0.8 and 0.2%, respectively, by exposure to formaldehyde vapor.

EXAMPLE II Fabric samples treated as in Example I are folded with pleating papers and steamed in a steam box for minutes with a prior water spray to about 20% pick-up. The pleat ratings, obtained in the same manner as the crease ratings for solutions A, B, C, D, and E, respectively, are 2.5 2.8, 2.8, 2.8, and 2.8, respectively. These fabrics similarly are characterized by the reduced wool odor.

The fabrics are placed on hangers and then hung in the steam box. A 37% formaldehyde solution is poured into the steam box and steam is admitted, whereupon the steam becomes laden with formaldehyde. After 20 minutes, the fabrics are removed from the steam box. Each fabric sample is devoid of the reduced wool odor and, furthermore, is devoid of a formaldehyde odor.

EXAMPLE III Skirts made from the fabrics of Example II are pleated as set forth therein and hung in a steam box, where they are subjected to the vapors of sublimed paraformaldehyde crystals at about 70 F. After one hour, any excess formaldehyde vapors are blown from the system. About 10 mol percent by weight of paraformaldehyde, based on the reducing agent is utilized. The characteristic reduced wool odor is eliminated by this treatment and no residual formaldehyde odor remains.

EXAMPLE IV To the following pad bath solution: 12.8% monoisopropanolamine sulfite 20% ethylene glycol 0.1% Synowet HR are added the various formaldehyde generating compounds set forth in Table II. The amounts given for the formaldehyde generating compounds correspond to 5, 10, 20 and 50%, respectively, of the moles of reducing agent padded onto the fabric.

Samples of the worsted fabric of Example I are padded to approximately wet pick-up with each of the resulting solutions, after which the samples are dried at 200 F. in a mechanical convection oven. A lustrous finish is imparted to the samples by steaming on a Hoffman press for 2 seconds between standard decater leader fabrics, followed by vacuum pumping for 10 seconds. The fabrics are evaluated for odor both before and after creasing without a water spray. The control fabric is similarly treated except that no formaldehyde generating compound is utilized.

The odor evaluations are conducted in an aluminum lined room in which the relative humidity is held to 45% 15% at 82 Fri-3 F. with a room dehumidifier. Also, the air in the room is constantly passed through an electrostatic precipitator which includes an activated carbon filter.

The fabric samples are placed in 6 x 8 inch round battery jars at 20% moisture content. These jars have ground edges and are covered with 8 x 8 x inch plate glass covers. The samples are maintained under these conditions for 2 days and are then evaluated individually by an odor-sensing panel of 10 persons on a scale of no odor, a very slight odor, a slight odor, a moderate odor, a heavy odor, and a very heavy odor.

TABLE II Dry Amount, Pressed Unpressed crease Additive percent odor odor ratings Reduced control Heavy Heavy 5 Untreated control Very slight.... Ver slight. 1. 0 Sodiurnl'onnaldehydebisulfite 0. 298 Moderate Moderate 3. 3 Do 0. 578 Slight Slight 3. 5 D0 1.156 Slight to Slight to 3. 3

moderate moderate. D0 2.890 Slight 3. 8 Paraformaldehyde. 0.060 Very slight.... Slight... 3.3 Do 0.120 Slight do 4.2 Do 0. 240 Very slight .....do 2. 7

to slight. Do 0.600 .....do Slight to 2.1

moderate. Hexamethylenetetramine 0.044 Slight Slight 3. 5 0. 088 do Slight to 3. 5

moderate. 0.176 Moderate Slight 2. 7 0. 440 Slight Very slight.-.. 3. 2

acetamide 0.169 Slight to Slight 3. 2

moderate. Do 0.338 Very Slight to ....do 2.6

slight. D0 0.676 .....do Very slight 3.4 Do 1. 690 Slight Very slight 3. 0

to slight. N-methylol- 0.192 ..d0....... Slight to 3.2

aerylamide. moderate.

Do 0. 384 .....d0 Very slight 3. 0

to slight. Do 0.768 Slight to do 3. 1

moderate. Do 1.920 Moderate do 2.9 Trimethylol- 0294 Very slight Slight... 3.0

melamine, 80 percent.

Do 0. 588 Very Slight to Very slight- 3. 5 slight. Do 1.176 Slight Slight 2, 9 D0 2. 940 Moderate to Very slight to 3. 2

heavy. slight.

EXAMPLE V Samples of the fabric of Example I are padded to 70% pick-up with an aqueous solution containing 6.4% monoisopropanolamine sulfite, 0.1% Synowet HR and 0.120% of paraformaldehyde (1 mole of paraformaldehyde per 10 moles of reducing agent utilized). In making up the pad solution, the system is heated to F. with stirring to dissolve the paraformaldehyde crystals. After ageing 1 l for 20 minutes, the fabric samples are dried relaxed in a Fleissner dryer, then semi-decated at a cycle of 5 seconds steaming and 2 minutes vacuum pumping to obtain a lustrous finish on the fabric.

The odor of the fabric samples is evaluated as in Example IV both before and after pressing in a dry state on a Hoffman press. Only a very slight reduced wool odor remains, compared to the very heavy odor characterizing the control fabric which is similarly treated but without paraformaldehyde. No odor of formaldehyde can be detected in these fabric samples.

EXAMPLE VI The reduced control fabric of Example V is cut and sewn into skirts, pleated with conventional pleating papers and steamed in an autoclave for 20 minutes to set the pleats.

A moderately heavy reduced wool odor is readily detected in these skirts. Paraformaldehyde crystals are placed at the base of the autoclave and heated, whereupon formaldehyde vapors permeate the skirts. After 60 minutes in this atmosphere, the skirts are removed. Neither a reduced Wool odor nor a formaldehyde odor can be detected in the skirts.

EXAMPLE VII The fabric of Example I is padded to 70% pick-up of an aqueous solution containing 6.0% monoisopropanolamine, 0.12% paraformaldehyde and 0.1% Synowet HR. This solution is obtained by heating the system with stirring to 120 F. to dissolve the paraformaldehyde crystals. After semi-decating by steaming for 1% minutes and vacuum pumping for 3 minutes, the fabric is wound onto the spindle of a package dye machine and placed in the machine. The machine is then sealed and the pressure therein is reduced to 60 mm. Hg. Into the evacuated machine is introduced an amount of S gas chemically equivalent to the monoisopropanolamine previously padded into the fabric, plus an amount calculated to fill the voids in the cylinder and fabric. This is accomplished by feeding S0 into the machine at a rate of 2 liters/ minute for 5 minutes.

After the pressure reaches atmospheric and the temperature reaches 140 F., air is forced through the autoclave to remove unreacted $0 if any, after which the fabric is removed from the machine.

Dry crease ratings of 3.2 are obtained with no characteristic reduced wool odor. A fabric similarly treated but without paraformaldehyde dissolved in the treating solution is characterized by a heavy reduced wool odor.

EXAMPLE VIII The procedure of Example VII is repeated except that after S0 is introduced into the machine, the pressure is decreased to 60 mm. after which the resulting partial vacuum is broken with air. The machine is then held at 71 cm. partial vacuum for minutes and the fabric removed and tested as before. Dry crease ratings of 4.0 are obtained and, again, no characteristic reduced wool odor is noticed.

EXAMPLE IX The procedure of Example VII is repeated except that S0 is blown through the fabric at 2 liters per minute for 5 minutes without previous evacuation of the machine. The fabric is permitted to stand in the SO -laden machine for 5 minutes, after which air is blown through the fabric for 30 minutes. Dry crease ratings of 2.7 are obtained with no trace of odor in the fabric.

EXAMPLE X The procedure of Example IX is repeated except that 1.0% Synsoft-LS polyethylene softener is added to the pad solution. Dry crease ratings of 3.2, with no reduced wool odor detectable, are obtained.

l 2 EXAMPLE XI The fabric of Example I is treated with the pad solution of Example X, semi-decated as in Examp e VII and sealed into a package dye machine. At a rate of 2 liters/ minute, S0 gas is blown through the fabric for 5 minutes. Air is then blown through the fabric for 5 minutes, after which ammonia and air are blown through the fabric until air leaving the machine is neutral. Dry crease ratings of 3.7 are obtained in this manner, with only very slight reduced wool odor in the fabric. No S0 or NH; odor is detected.

A control fabric similary treated but without paraformaldehyde in the original solution is characterized by a moderate reduced wool odor.

EXAMPLE XII The bisulfite addition product of aqueous formaldehyde and sodium metabisulfite (sodium formaldehyde bisulfite), is added, where indicated, to various aqueous pad solutions as set forth in Table III. Samples of the fabric of Example I are padded to 100% pick-up with these solutions and dried at 200 F. unless otherwise specified.

Odor evaluations are made before and after creasing of the samples on a Hoffman press without prior water spraying. The dry crease ratings and odor evaluations are given in Table III.

TABLE III Drying tempera- Odor ature, Dry Pad solution F. crease Before After 1. Untreated control 1.0 None None. 2. 5% monoisopropanolamine 200 4. 3 Heavy Heavy.

sulfite plus 0.1% Syn-Fae 905.

3. 1% sodium formaldehyde 200 4. 0 None.. None.

bisulfite plus solution of No. 2. 4. 2% sodium formaldehyde 200 4 0 ...do D0.

bisulfite plus solution of No. 2. 5. 5% sodium formaldehyde 200 4 0 -do Do. bisullite plus solution of No. 2. 6. 8.1% sodium tormalde- 2.3 .-do-.. Do.

hyde bisulfite. 7. D0 200 1.5 do... Do. 8. 8.1% sodium formalde- 3.9 do Very hyde bisulfite plus 20% slight. ethylene glycol. 9. D0 200 2. 2 Slight. Olly.

10. 8.1% sodium formalde- 4. 7 None. None.

hyde bisulfite plus 20% ethylene glycol plus 6.4% monoethanolamine sulfite. Do 200 2.8 Very Do.

slight. 5O

1 Room temperature.

EXAMPLE XIII Dimethylolethanolamine sulfite is prepared by reacting 60 grams of paraformaldehyde with 61 grams of ethanolamine at 50-70 C. After cooling and filtering through glass wool, the reaction mass is saturated with S0 gas while being maintained cool with an ice bath. The resulting product is added (2%) to an aqueous solution containing 5% monoisopropanolamine sulfite and 0.1% Syn- Fac 905. The fabric of Example I is padded to pick-up with this solution and dried at 200 F.

The fabric is then creased on a Hoffman press without prior water spraying. Excellent creases, which are durable to subsequent wetting, are produced in this manner and only a very slight reduced wool odor remains in the fabric.

Similar results are obtained with dimethylolisopropanolamine sulfite which may be produced by substituting 75 grams of isopropanolamine for the ethanolamine in the above procedure.

EXAMPLE XIV N-methylolformamide is produced by reacting 30 grams of paraformaldehyde with 45 grams of formamide 13 at 120-150 C. After cooling, the resulting product is mixed in equal parts with monoisopropanolamine sulfite. Thirteen (13) grams of this mixture are blended with 30 grams of ethylene glycol, after which 67 grams of the glycol are added. After stirring to insure complete dissolution, the resulting solution is padded to 100% pick-up onto the fabric of Example I. Again, excellent dry creases are obtained with little or no noticeable reduced wool odor.

EXAMPLE XV The fabric of Example I is padded to 100% pick-up with an aqueous solution containing 4.5% monoisopropanolamine sulfite, 1.5% paraformaldehyde, 0.1% Syn- Fao 905 and 7.2% urea.

The fabric is dried at 200-225 F. and semi-decated on a Hoffman press at seconds steam followed by 60 seconds vacuum while contained between two pieces of decater fabric.

This fabric, weighing 1482 grams, is then rolled onto the beam of a laboratory gas treating machine, placed in the machine and heated to 140 F. Ammonia gas (2.6 grams) is added to the system and circulated for six minutes. The excess ammonia is vented to the outside. Sulfur dioxide gas (51.4 grams) is then added to the system and, after complete addition, is circulated for six minutes. The excess sulfur dioxide gas is vented to the outside.

Additional ammonia (1.3 grams) is then added to the system and circulated for six minutes. A final venting and exhausting is conducted for 10 minutes. The fabric is removed from the machine and tested.

The initial dry crease rating is 3.5. This rating after ageing at room conditions for one (1) week, increased to 4.3.

No reduced wool odor is noticed.

The process of this invention may be utilized in any process involving the use of reducing agents to modify the characteristics of keratin fibers. A most surprising area of utility is in the presensitizing field. As noted previously, aldehydes, particularly formaldehyde, inhibit presensitization. Consequently, it is most surprising that configurations can be obtained which are as good as, or better than, configurations obtainable when aldehydes are not utilized. This is particularly true when the reducing agent and formaldehyde are applied to the keratin fibers from a single solution, or at least are present in the fabric simultaneously during setting. This phenomenon may be explained by the fact that the aldehyde may not react with the keratin fiber until after setting has occurred. The aldehyde may then react to eliminate any further propensity for durable setting. This propensity has been known to manifest itself in a crease-removing manner. Since this propensity would no longer exist under this theory, the resulting crease performance would be enhanced. It is to be understood, however, that there is no apparent explanation for the phenomenon whereby the odor of reduced wool is substantially minimized by treatment with the compounds of this invention.

That which is claimed is:

1. In the process of setting garments containing keratinic fibers with a reducing agent comprising (a) contacting a fabric containing keratinic fibers with a solution of a reducing agent,

(b) drying to produce a presensitized fabric,

(c) preparing a garment from said presensitized fabric,

and

(d) setting said garment in a given configuration by heating, the improvement which comprises adding a formaldehydegenerating compound selected from the group consisting of methylol amides and methylol amines to said solution of a reducing agent to generate formaldehyde during said setting procedure for the purpose of substantially minimizing any reduced keratin fiber odor.

2. The improvement of claim 1 wherein a keratinic fiber swelling agent is added to the solution containing the reducing agent and the formaldehyde-generating compound.

3. The improvement of claim 2 wherein the keratinic fiber swelling agent is urea.

4. The improvement of claim 2 wherein a low molecular weight polyhydroxy compound is substituted for said swelling agent.

5. The improvement of claim 4 wherein the low molecular weight polyhydroxy compound is ethylene glycol.

References Cited UNITED STATES PATENTS 2,351,718 6/1944 Speakman 8127.6 2,508,713 5/1950 Harris et al. 8127.6 2,806,762 9/1957 Ramirez et al. 8127.5 2,870,041 1/1959 Waddle et al. 8-1163 X 2,983,569 5/1961 Charle 8127.5 3,051,544 8/1962 Wolf et al. 8128 3,151,439 10/1964 Dusenbury 8-127.6 2,740,727 4/ 1956 Littleton 8128 FOREIGN PATENTS 443,359 2/1936 Great Britain.

OTHER REFERENCES Speakman et al., Journal of the Textile Institute; pp. T627T628 (1958).

Wolfram et al., Journal of the Society of Dyers and Colorists, vol. 76, pp. 169-173 (1960).

DONALD LEVY, Primary Examiner J. CANNON, Assistant Examiner US. Cl. X.R. 38-144