US3402990A - Treatment of keratinic fibers with a reducing agent and an amino acid - Google Patents

Description

, 3,402,990 Patented Sep 3,402,990 TREATMENT OF KERATINIC FIBERS WITH A REDUCING AGENT AND AN AMINO ACID Bradley Dewey, New London, N.H., assiguor to Deering Milliken Research Corporation, Spartanburg, S.C., a

corporation of Delaware No Drawing. Filed Jan. 14, 1964, Ser. No. 337,523

11 Claims. (Cl. 8-127.6)

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

Fabrics containing Wool fibers, 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 in many ways to improve fabrics containing wool fibers, e.g., to impart durable creases, pleats, and/or flat configurations to wool fabrics, to impart to these fabrics a propensity for such setting operations, to elasticize wool fabrics and for many other purposes.

Wool fibers 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 fibers which have 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 wool fibers with reducing agent, 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 wool 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 objectional 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 wool fibers has been solved in accordance with this invention by contacting reduced wool fibers, having the characteristic unpleasant odor, with an amino acid compound. This compound may be applied as such or by way of another compound which, upon heating, chemicalactivation, or even dissolution in a solvent, generates the desired amino acid compound.

The term amino acid compound as utilized herein, defines compounds derived from amino acids, particularly the N-alkyl, N-alkanol and N-acyl amino acids and metal salts and anhydrides thereof which substantially elimi nate the characteristic, unpleasant odor associated with wool fibers which have been treated with reducing agents capable of breaking the disulfide linkage of the wool fiber molecule.

Highly preferred amino acid compounds are the N- alkyl aminocarboxylic acids and their alkali-metal salts, particularly sarcosine and sodium or potassium sarcosinate. These compounds not only substantially eliminate the odor associated with reduced wool fibers but also are readily available and cost less than corresponding acids which give substantially similar results. Anhydrides and other metal salts of the N-akyl aminocarboxylic acids are similarly suitable, as are the N-alkanol and N-acyl derivatives. I

Although the above compounds constitute preferred amino acid compounds for use in accordance with this invention, other compounds corresponding to the following general formula are similarly useful:

wherein at least one of R and R is alkyl, alkanol or acyl, preferably lower alkyl or lower alkanol (e.g., containing up to about 8 carbon atoms), and acyl containing from about 6 to about 20 carbon atoms, the remaining R or R if either remains, being hydrogen, alkyl, alkanol or acyl; wherein R is hydrogen, alkyl or alkanol, preferably lower alkyl or lower alkanol; A is an acid grouping, or metal salt thereof or an acid anhydride grouping, x is a number from O to about 10; and wherein R is selected from hydrogen, alkyl, hydroxyalkyl, aralkyl, alkaryl, aromatic phenol, alkyl phenol, alkylcarboxylic acid, mercaptan, dialkyl, sulfide, alkyldiiodophenoxy-diiodophenol, N-alkyl guanidine, alkylamine, hydroxyalkylamine, C-alkyl carbamide, C-alkyl amide, alkyl imidazone, 3-alkyl indole, lower alkyl substituents of the above and the like.

Typical acids from which N-alkyl or N-alkanol derivatives corresponding to the above formula can be produced, are the monoamino-monocarboxylic acids, wherein A is carboxy-l and 15:0, such as glycine (wherein R is hydrogen, glycin (R is C H OH), alanine (R is CH aline CH: 7 R ts-( 111) norvaline (R is CH CH CH leucine norleucine (R is --CH CH CH CH isoleucine ornithine (R is -CH CH CH NH citrulline (R is -(CH NHCONH and the like; heterocyclic amino acids, such as histidine (R is -CH C H N tryptophane (R; iS-CHr-C and such acids as proline Not only should at least one amino-hydrogen atom of the above acids be alkylated or alkanolated, but also, any available hydrogen or other grouping in said compounds can be similarly alkylated or alkanolated.

The above N-alkyl or N-alkanol amino acids may be derived from acids other than the above. More particularly, aminosulfonic, aminophosphonic, aminophosphoric acil and the like may be substituted for the equivalent aminocarboxylic acids shown above.

The preferred alkyl substituent is methyl or ethyl for availability, ease of production and degree of effectiveness in eliminating the odor of reduced wool fibers.

Typical acids from which N-acyl aminocarboxylic acids and their metal salts may be derived include fatty acids, such as formic, acetic, propionic, butyric, valeric, caproic, enanthylic, caprylic, pelargonic, capric, undecylic, lauric, tridecoic, myristic, pentadecanoic, palmitic, margaric, stearic, nondecylic, arachidic, behenic and so on; corresponding unsaturated fatty acids, particularly oleic; aroyl, such as benzoyl, naphthoyl and the like; substituted aroyl, such as chlorobenzoyl, nitnobenzoyl and the like.

The above N-alkyl, N-alkanol or N-acyl compounds may be utilized as such, in the anhydride form, or in the form of a metal salt. Any metal may be utilized, for example, alkali-metals, such as sodium, potassium and the like; alkali-earth metals, such as calcium, barium, strontium and the like; transition metals, such as iron, cobalt, nickel, ruthenium, palladium, osmium, iridium, platinum and the like; non-transition metals, such as aluminum, gallium, indium, thallium and the like; as well as Groups IV, V, VI, and VII metals, such as tin, lead, antimony, bismuth, plutonium, manganese and the like.

The above compounds may be utilized to eliminate the characteristic odor of wool fibers which have been treated with any convention reducing agents utilized for setting wool fibers, i.e., those capable of rupturing the cystine disulfide linkage of the wool fiber molecule.

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-soluble salts, such as sodium potassium or ammonium thioglycollate; mercaptans, such as hydrogen sulfide and sodium or potassium hydrosulfide; alkyl mercaptans, such as butyl or ethyl mercaptans and mercaptan glycols, such as beta-mercaptoethanol; ammonium bisulfite, sodium sulfide, sodium hydrosulfide, cystine hydro chloride, 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 wool fibers, after which the fabric is set in a durable configuration, e.g., creased, pleated and/or flat,

4 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 containing wool fibers also 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 reducing agent solutions utilized for treating fabrics 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 and 111,447, 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, pentamethylene 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 hydr-oxyl groups include the polyfunctional alcohol glycerols such as glycerine, quintenyl glycerine, diethylglycerol and mesicerin, as well as trimethylol ethane, trimethylol butane, tris(hydroxymethyl)aminomethane and others. Glycol ethers, such as the water-soluble or dispersible 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 constitutes the most readily available and desirable swelling agent, although any other material which will swell. wool fibers in an aqueous medium is suitable. For example, guanadine compounds such as the hydrochloride; formamide, N,N-dimethylformami-de, acetarnide, 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 by weight provide noticeable improvement. Larger amounts of up to about or higher may be utilized, of course, if the particular end 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 US. patent application Ser. No. 278,359, the fabric is impregnated with a reducing agent precursor compound, finished by conventional mill finishing operations, and then exposed to a gaseous reducing 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 wool 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 wool 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-diethyl ethanolamine, N,N-diisopropyl ethanolamine, N-aminoethyl ethanolamine, N-methyl diethanolamine, n-propanolamine, isopropanolamine, triisopropanolamine, n-butanolamine, dimethylbutanolamine, dimethylhexanolamine, polyglycolamines of the general formula 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 suitable 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'CONH wherein x=l, and R is alkyl or aryl (e.g., hydrazides, such as acetoyl hydrazide butyrohydrazide, benzoylhydrazide, and the like); hydrazines 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-hydroxyethyl piperazine, N-amino ethyl 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 aldehydes 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, cinnamaldehyde, 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.

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 anhydrous, 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 obtained 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 W001 fibers, i.e., is capable of rupturing the disulfide bonds of the wool fiber molecular structure. It is not known with certitude if a reducing agent per se is formed in situ on the wool 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 W001 fibers and it is possible that the pre-treatmerit of the fibers with one of the precursor chemicals may merely sensitize the fibers for more efficient reaction of the wool 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 wool 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 wool 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 S possibly to produce monoisopropanolamine sulfite in situ on the fabric. On the other hand, if monoisopropanolamine 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 wool 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. 50-52 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. Wool fibers tend to degrade considerably during prolonged storage under basic conditions. It is preferred, therefore, that a sufficient 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 presensitizing 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 odor-eliminating 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 amino acid 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 whichthe amino acid 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 amino acid compound should be appliedto the fabric which eliminates the reduced keratin fiber odor. In this regard, an excess of amino acid compound may be utilized if desired and the excess removed by heating and/0r washing the fabric.

Since there is no readily available technique for measuring the degree of reduction of disulfide linkages of the wool fibers treated with reducing agentjthere is no clear way to prescribe what amount of amino acid 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 amino acid compound is applied. If the reduced wool fiber odor is eliminated, but the mild odor of the amino acid compound remains, the fabric may be heated or Washed to remove the residual odor without reinstituting the reduced wool 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 amino acid compound to be utilized again is subjective. For example, the amino acid 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 wool fiber odor remains, additional amino acid compound may be applied to the fabric. Conversely, if the crease performance is not as high as desired, less amino acid 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 amino acid compound 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 amino acid compound 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 amino acid compound, based on the moles of reducing agent Which are utilized in the treatment of the wool fibers. In the gas type presensitizing process, the amino acid compound content 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 wool fibers, particularly those composed entirely of wool fibers, it is also applicable to fabrics wherein synthetic, natural,.or other fibers are blended with the wool component.-By wool fibers as utilized herein is meant animal fibers such as 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 acrylonitn'le lhomopolymers or copolymerscontaining at least about 85% combined acrylonitrile, such as acrylonitrile/ static precipitator which includes an activated carbon filter.

methyl acrylate (85/ and cellulosics, such as cellulose acetate and viscose rayon. Of the natural fibers which may be blended with the wool 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 Hoffman 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 170 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 running from 1 (no appreciable crease) to 5 (very sharp crease).

The fabric samples are placed in 6 X 8 inch round battery jars at moisture content. These jars have ground edges and are covered with 8 x 8 x A 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.

are added the various amounts of sodium sarcosinate as set forth in Table I. 'Ilhe amounts given for sodium sarcosinate correspond to 5, 10, 20 and 50% respectively, of the moles of reducing agent padded onto the fabric.

Samples of an all-wool fabric, Deering Milliken Style Number 8012, are padded to approximately 100% Wet pickup 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 as set forth above. The reduced control fabric is similarly treated except that no sodium sarcosinate is utilized. Odor evaluations are conducted in an aluminum lined room in which the relative humidity is held to 45% i5% at 82 F.i3 F. with a room dehumidifier. Also, the air in the room is constantly passed through an electro- Substantially similar results are obtained when 0.168, 0.335, 0.671 and 1.680%, respectively, by weight of sarcosine is substituted for sodium sarcosinate.

Sodium sarcosinate and sarcosine alone have little or no effect on the crease retention properties of a wool fabric. It can be seen, therefore, that the use of amino compounds has a synergistic effect on the crease retention properties of wool fabrics, as well as providing control over the unpleasant odor of reduced wool fibers.

Example II 7 Samples of the fabric of EXample I are padded to 70% pickup with an aqueous solution containing 6.4% monoisopropanolamine sulfite, 0.1% Synowet HR anionic Wetting agent and 0.418% of sodium sarcosinate (1 mole of sodium sarcosinate per 10 moles of reducing agent utilized). After ageing 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 sample is evaluated as in Example I both before and after pressing without adding water on a Hoffman press. Only a very slight reduced wool odor remains, compared to the heavy odor characterizing the control fabric which is similarly treated but without sodium sarcosinate. No odor of sodium sarcosinate can be detected in the fabric samples. Furthermore, enhanced crease retention is again noted.

Example III The fabric of Example I is padded to 70% pickup of an aqueous solution containing 6.0% monoisopropanolamine, 0.418% sodium sarcosinate and 0.1% Synowet HR. 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 S0 gas chemically equivalent to the monoisopropanolamine previously padded onto the fabric, plus an amount calculated to fill the voids in the cylinder and fabric. This is accomplished by feeding S0 gas into the machine at a rate of 2 liters/ minute for 5 minutes.

After the pressure reaches atmospheric and the temperature reaches F., air is forced through the autoclave to remove unreacted S0 if any, after which the fabric is removed from the machine.

Dry crease ratings of 3.5 are obtained with no characteristic reduced wool odor. A fabric similarly treated but without sodium sarcosinate dissolved in the treating solution is characterized by a heavy reduced wool odor and a lower dry crease rating.

Example IV The procedure of Example 111 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 10 minutes and the fabric removed and tested as before. Dry crease ratings of 4.0

11 are-obtained and, again, no characteristic reduced'wool odor is noticed. t

' Example V The procedure of Example III is repeated except that SO gas is blown through the fabric at Zliters, per minute for 5 minutes without preyious 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 VI The procedure of Example V 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.

Example VII The fabric of Example I is treated with the pad solution of Example VI, semi-decated as in Example III and sealed into a package dye machine. At a rate of 2 liters/ minute, S 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 ammonia odor is detected.

A control fabric similarly treated but without sodium sarcosinate in the original solution is characterized by a moderate reduced wool odor and a lower dry crease rating.

12 an aqueous solution containing sodium bisulfite, 0.1% Syn-Fae 905 and the following amino-acid compounds:

' Percent (A) N-methyl alanine 0.384 (B) N-methyl norleucine' 0.542 (C) Sodium-N-methyltyrosinate 0.820 (D) Sodium-'N-methylserinate 0.530 (E) N-methyl cysteine 0.507 (F) Sodium-N-methylglutamate 0.687 (G) Sodium-N-methyllysinate I 0.685 (H) N-methyl asparagine 0.545 (I) N-methyl proline' 0.482 (J) N-methylol alanine 0.448

The procedure of Example II is repeated except that the amounts shown in Table II of lauroyl sarcosinate, sodium oleyol sarcosinate, and sodium cocoyl sarcosinate are substitued for the sodium sarcosinate. Odor evaluations before and after pressing are shown as is the crease rating obtained.

Sodium oleoyl sareosinate Sodium cocoyl sarcosinate,.

l 1. 5 Very Slight" 1. 5 D

Example VIII The fabric of Example I is padded to 100% Pickup with an aqueous solution containing 4.5% monoisopropanolamine sulfite, 0.336% sodium sarcosinate, 0.1% Syn-Fac 905 and 7.2% urea.

The fabric is dried at ZOO-225 F. and semi-decated on a Hofiman press at 15 seconds steam followed by 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 at 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) isthen 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 aging at room conditions for one (1) week, increased to 4.3.

No reduced wool odor is noticed.

, Example TX The fabric of Example Iis padded to pickup with The proces of this invention may be utilized in any process involving the use of reducing agents to modify the characteristics of wool fibers. A most surprising area of utility is in the presensitizing field. As noted previously, the amino acid compounds tend to inhibit presensitization. Consequently, it is most surprising that configurations can be obtained which are even better than configura-- tions obtainable when these compounds are'not utilized. In fact, the crease ratings in most instances are far superior to the reduced control fabrics. This is particularly true when the reducing agent and amino acid compound are applied to the wool 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 amino acid compound may not react with the wool fiber until after setting has occurred. The amino acid compound 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 novlonger exist, under this theory, the resulting crease performancewould be enhanced. It is to be understood, however, that there is no apparent explanation for the synergistic phenomenon noticed herein, whereby enhanced creaseratings are obtained nor for the phenomenon whereby theodor of reduced wool is substantially eliminated by treatment with the compounds of this invention.

That which I claim is:

1. A process for eliminating the characteristic odor 13 from a wool fiber which has been treated with a reducing agent comprising contacting said fibers with an amino acid compound.

2. The process of claim 1 wherein the compound comprises an alkali metal salt of an aminocarboxylic acid.

3. The process of claim 2 wherein the acid comprises sarcosine.

4. The process of claim 3 wherein the compound comprises sodium sarcosinate.

5. The process of claim 1 wherein the fibers are treated with sarcosine.

6. A process for eliminating the characteristic odor from a wool fiber which has been treated with a reducing agent comprising contacting said fibers with a compound selected from the group consisting of an N-alkyl amino acid, an N-alkanol amino acid, an N-acyl amino acid and metal salts and anhydrides thereof.

7. In a process wherein a fabric containing wool fibers is impregnated with an aqueous solution of a reducing agent and set under conditions of heat and pressure in a desired configuration, the improvement which comprises contacting said fabric with an amino acid compound, whereby any characteristic reduced wool odor is substantially minimized.

8. Wool fibers which have been treated with a reducing agent and an amino acid compound.

9. W001 fibers which have been reacted with a reducing agent and a compound selected from the group consisting of an N-alkyl amino acid, an N-alkanol amino acid, an N-acyl amino acid and metal salts and anhydrides thereof.

10. The wool fibers of claim 9 wherein the compound I comprises an N-alkyl aminocarboxylic acid.

11. The wool fibers of claim 9 wherein the compound comprises an alkali metal salt of an N-acyl aminocarboxylic acid.

No references cited.

NORMAN G. TORCHIN, Primary Examiner.

J. CANNON, Examiner.

Claims (1)

1. A PROCESS FOR ELIMINATING THE CHARACTERISTIC ODOR FROM A WOOL FIBER WHICH HAS BEEN TREATED WITH A REDUCING AGENT COMPRISING CONTACTING SAID FIBERS WITH AN AMINO ACID COMPOUND.