US2427097A - Shrinkproofing and feltproofing of keratinous textile fibers - Google Patents

Description

Patented Sept. 9, 1947 aizimw SHRINKPROOFING AND FEL KERATINOUS rnx'rn.

Jonas Kamlet, New Yo berg and Leo Be No Drawing. Application A Serial No. 550,8

7 Claims. 1

This invention relates to a process for shrinkproofing and feltproofing of keratinous textile fibers. It relates further to a process for improving the properties of wool, and has particular relation to a new and improved method of treating keratinous textile fibers, such as wool, with chlorinating agents.

The well known tendency of keratinous textile fibers to felt when subjected to mechanical working, will cause shrinkage during laundering. This is a serious technical disadvantage inherent to many applications of woolen goods, e. g. clothing, blankets, knit goods, etc. The obviation of this disadvantage is a Primary object of this invention.

The main object of our present invention is to improve the properties of keratinous textile fibers by subjecting them to the action of a chlorinating agent under conditions which prevent or substantially reduce detrimental secondary eiTects of the chlorine on the fibers. More particularly, it i'sthe main object of our invention to reduce the 'felting properties and shrinking of Wool, and simultaneously improve its wearing properties, particularly the abrasion resistance and tensile strength.

Other objects and the advantages of our invention will be apparent from the following specification, which describes by way of example some preferred embodiments of our invention.

It is well known that halogenation, and particularly chlorination, renders wool resistant to shrinkage and felting on laundering. The compounds heretofore used for this treatment are the free halogens, hypohalous acids, inorganic and organic hypohalites, and certain N-halogenated .organic compounds such as the N-chloramides fand imides. These substances contain the group WY where W is halogen, divalent oxygen, (-O) or singly bonded tervalent nitrogen, and Y is halogen. All of these have usually been applied from aqueous or alcoholic solutions. In each case, the effective halogenating agent is an electropositive halogen ion. Even when gaseous chlorine is used on air-dried wool, it is believed that the fibers contain sufficient inherent moisture to liberate the required quantity of electropositive chlorine.

The disadvantages connected with the prior processes for the chlorination of Woolen fibers or fabrics have been generally known. Although chlorination of woolen fabrics results in reduction of their felting properties, the chlorinated fabrics become harsh and yellow, andtheir tenrk, er,

TPROOFIN G OF E FIBERS N. Y., and Mark Weis- Providence, R. I.

ugust 23, 1944, 58

sile strength and abrasion resistance is substantially reduced. Moreover, the known processes often result in uneven chlorination of wool. In a continuous process for treatment of piece goods, the first part of the fabric entering the bath may be overtreated and the last part of the fabric leaving the bath may be undertreated.

In order to avoid such undesirable secondary effects of chlorination, the use of compounds containing electropositive halogen atoms, in the presence of compounds containing aminoand/or imino groups, has been suggested. By this modified process the felting properties of wool may be diminished, but its wearing properties are simultaneously impaired. It has also been suggested to treat wool with a neutralized hypochlorite solution containing formaldehyde. This process has not proved satisfactory either, because such hypochlorite solution has a substantial oxidizing, and therefore deteriorating effect on wool, and this effect cannot be prevented by the presence of ancillary agents such as formaldehyde in the hypochlorite solution.

The basis of the present invention is the finding that the shrinking and felting of keratinous textile fibers may be obviated without discoloration of the treated material or other undesirable side effects, and that a substantially shrinkproof and non-felting fabric of improved wearing properties, especially increased resistance to abrasion and higher tensile strength may be obtained by the following sequence of steps of treatment:

(a) The keratinous material (e. g., wool, or a mixture of wool with other fibers or textile materials) is treated with an aqueous solution of formaldehyde, or a formaldehyde-yielding compound (such as trioxymethylene, paraformaldehyde, trioxane, methylal, etc), followed by (b) the treatment of the material thus pre-treated with an aqueous solution of a member of the group of compounds of the general formula where R is a member ydro y a y member of the chlorine, and t the presence or of formaldehyd pound.

e or a formaldehyde-yielding com- Typical examples of the group of compounds of general formula and the water-soluble salts thereof are: N-chlorsulfamic acid, sodium N-chlorsuliamate, potassium N, N-dichlorsulfamate, N-chlor, N-methylsulfamic acid, sodium N-chlor, N-cyclohexylsulfamate (Sveda, U. S. Patent 2,288,976 of July '1, 1942), sodium N-chlorbenzene sulfonamide, potassium N-chlcr,- p-toluene sulionamide, so-

- dium p-N,N-dichlorsulfonamidobenzoate, etc.

The compounds found to be most suitable for the chlorination envisaged by the present invention are the water-soluble salts of N-chlorand N,N-dichlorsulfamic acid, e. g., sodium N-chlorsulfamate, sodium N,N-dichlorsulfamate.

The simplest sulfonamide is sulfamic acid (aminosulfonic acid), HO.SO2NH2. This com pound was first described by Rose (Pogg. Ann. 33, 235 (1834); 42, 415 (1837); 61, 397 (1844), and Berglund (Lunds Univ. Acta 13, 4 (1875), who prepared it by decomposing lead imidosulfonate with hydrogen sulfide. Sulfamic acid is now being manufactured on a large scale industrially by the reaction of urea with fuming sulfuric acid (Baumgarten, U. S. Patent 2,102,350 of Dec. 14, 1937) or with chlorsulfonic acid (Wyler, U. S. Patent 2,109,952 of March 1, 1938), and has found a wide field of industrial applicability (Cupery and Gordon, Ind Eng. Chem., 34, 792, July, 1942).

The N-chlorinated and dichlorinated sulfamates may be obtained by reacting an aqueous solution of one mole-equivalent of an alkali metalor an alkali-earth metal sulfamate with an aqueous solution of more than 1.50 moles and preferably two moles of hypochlorous acid. The reaction proceeds almost, instantaneously by mixing the reagents at room temperature, and probably occurs in two stages. The first results in the formation of the N-monochlorsulfamate in quantitative yield by the reaction of equimolar amounts of the sulfamate and the hypochlorous acid:

(where M represents an equivalent of an alkalimetal or an alkali-earth metal).

The second stage results in the conversion of part of the N-monochlorsulfamate obtained in the first stage to N,N-dichlorsulfamate, thus:

This reaction is indicated as reversible since, at this stage, the stability of the N,N-dichlorsulfamate is such that, as its relative concentration increases, its tendency to hydrolyze increases similarly. In accordance with the mass action law, the reaction equilibrium is shifted from right to left as the molar fraction of N,N-dichlorsu1famate increases.

If 0.51 mole of hypochlorous acid is available for reaction with each mole-equivalent, of N-.

,monochlorsulfamate formed in the first stage (original HOCl-NI-IzSOzOM molal ratio: 1.51:1.00) the hypochlorous acid is quantitatively converted to N,N-dich1orsulfamate, and there is thus obtained a mixture of 0.51 mole-equivalents of N,N-dichlorsulfamate (MOSOzNClz) and 0.49 mole-equivalents of N-monochlorsulfamate (MOSOzNI-ICI). However, if 1.00 mole Of hypochlorous acid is available for reaction with each mole-equivalent of N-monochlorsulfamate formed in the first stage (original HOC1NH2SQ2OM molal ratio=2.00:1.00) the conversion to N,N-dichlorsulfamate is not quantitative. There is obtained a mixture of 0.85 to 0.95 mole-equivalent of N,N-dich1orsulfamate (MOSOzNClz) and 0.05 to 0.15 mole equivalent of N-monochlorsulfamate (MOSOzNHCl). The use of more than two moles of hypochlorous acid per mole equivalent of alkali metalor alkali-earth metal sulfamate does not result in complete suppression of N-monochlorsulfamate formation. At least 0.05 mole of N- monochlorsulfamate is always obtained with each mole of N,N-dichlorsulfamate. The unreacted hypochlorous acid is comparatively unstable and is destroyed or dissipated in the course of preparing, concentrating, storing or using the compositions of the present invention. Thus, no advantage is obtained by using more than two moles of the hypochlorous acid per mole equivalent of sulfamate.

The sodium N-chlorsulfamate/N,N-dichlorsulfamate mixtures have the advantage of being prepared from cheap and readily available raw materials. A mixture of 0.95 mole of sodium N,N-dich1orsulfamate and 0.05 mole of sodium N-chlorsulfamate contains 36.9% of active chlorine. The corresponding llthium-N-chlorsulfamate/N.N-dichlorsu1famate mixtures contain 40.5 of active chlorine, and are believed to have a higher content of electropositive chlorine thar any stable N-chlorinated sulfonamide heretofort described.

Beside the method heretofore described (involving the reaction of one mole of alkali metalor alkali-earth metal sulfamate with two mole of hypochlorous acid, first used by Traube am von Drathen (Berichte, 51, 114 (1918) to obtaii an impure potassium N,N-dichlorsulfamate) number of alternate methods are available f0 preparing the chlorinated sulfamate composition of the present invention, Thus:

(a) One mole-equivalent of sulfamate is re acted with 1.51 to 2.00 mole-equivalents of hypo chlorite:

The MOH liberated by this reaction may be net tralized unless its presence in the reaction mix ture is desirable.

(b) One mole of .sulfamic acid is reacted wit 1.51 to 2.00 mole equivalents of hypochlorite:

HOSO2NH2+MOC1-+MOSO2NHC1+H2O MOSOzNHCH-MOCIQMOSOaNCh-i-MOH The MOH liberated by this reaction may similar be neutralized.

(0) One mole equivalent of sulfamate is ch11 rinated with 1.51 to 2.00 moles of chlorine in tl presence of 1.51 to 2.00 mole-equivalents of t alkali:

Other and obvious modifications of the abo will occur to any person skilled in the art. Th1 in reaction (17) it is obvious that the use of equimolar mixture of hypochlorous acid and h pochlorite will obviate the necessity of neutral ing the liberated MOH; et cetera, et cetera,

It should be understood, however, that this i vention is in no wise limited to the above-me tioned derivatives of sulfamlc acid. Among 0t ers found to be suitable are such compounds the N -alkali metal-N ,N-dichlor-N -acylsu anilamides (Hultquist and Crossley, U. S. Petr 2,328,455 of August 31, 1943) in addition to those other sulfonamides and their derivatives enumerated above.

Chlorination by means of chlorosulfamates in acid solution takes place slowly and homogeneously and results in uniform products of high quality. The addition of a cationic r acid-resistant wetting agent to the bath has proved to facilitate thorough and uniform penetration of the woolen goods with the constituents of the bath.

We have further found that the protective action of formaldehyde on wool at temperatures of -50 C. may also be obtained if no pretreat ment with formaldehyde of the'wool to be chlorinated takes place, but the formaldehyde is present in the acid chlorosulfamate bath used for chlorination.

The length of the treatment may be varied in accordance with the concentration of the reagents. Thus, periods of 30 to 60 minutes have been found suitable for the chlorination. The temperature may conveniently be within the range of practical operating conditions, i. e, between 5 C. and 60 C. However, these conditions are by no means critical, but may be modified to suit individual circumstances without changing the basic nature of the present invention. It is obvious that an increase in reaction temperature may be compensated by a corresponding decrease of the reaction time. I

The process of the present invention is applicable generically to keratinous fibers or their mixtures with other textile fibers whether the fibers be a textile, yarn or woven goods. Wool is the principal keratinous fiber, but this invention is applicable to all other keratinous textiles, such as rabbit fur.

The following examplesare given to define and illustrate the present invention but in no way to limit it to reagents, proportions or conditions described therein. Obvious modifications will occur to any person skilled in the art. All proportions given are parts by weight.

Preparation of chlorinated sulfamates Example I.-97 parts of crystalline sulfa-mic acid (1.00 mol) are added in small portion to 1012 parts of a well-cooled 14% solution of sodium hypochlorite (1190 moles). The resultant solution is then cautiously neutralized with 61 parts of glacial acetic acid 1.00 mole), and then contains 169.2 parts of sodium N,N-dichlorsulfamate (0.90 mole) and 15.4 part of sodium N- chlorsulfamate (0.10 mole) Example II.A quantity of a high test commercial bleaching powder containing 143 parts of calcium hypochlorite (two mole-equivalents) is dissolved in a solution of 116 parts of calcium sulfamate (one mole equivalent) in 2000 parts of water. The mixture is vigorously shaken for two hours at room temperature, and is then filtered from the precipitate of calcium hydroxide formed. The resultant filtrate is neutralized with hydrochloric acid and assayed, on the basis of active chlorine content, 081 mole-equivalent of calcium N,N-dichlorsulfamate and 0.19 moleequivalent of calcium N-chlorsulfamate.

Example [IL-119 parts of crystalline sodium sulfamate 1.00 mole) is dissolved in 852 parts of 14% sodium hypochlorite solution (1.60 moles). The resultant solution is then neutralized with 60% sulfuric acid and assayed, on the basis of active chlorine content, 0.60 mole of sodium N, N

dichlorsulfamate and 0.40 mole f sodium N- chlorsulfamate.

Example IV.-A solution of 106 parts of soda ash (two mole-equivalents) in 2000 parts of ice water is chlorinated until 142 parts of chlorine gas (two moles) has been absorbed. To the resultant 5.25% hypochlorous acid solution (1.0 M) is now added 119 parts of crystalline sodium sulfamate (1.00 mole). There is thus obtained a solution assaying 0.95 mole of sodium N,N- dichlorsulfamate and 0.05 mole of sodium N- chlorsulfamate.

The active chlorine concentrations of the compositions of the present invention are readily Treatment of materials Erample V.-50 grams of an air-dried woolen fabric are immersed for 30 to 60 minutes at 20-25 C., in a bath containing per liter of water 1.0 gm. of a wetting agent (e. g., the sodium salt of a highly sulfonated castor oil, propylnaphthalene sulfonic acid or similar acid resistant wetting agent), and

15520.0 cc. of 35% aqueous formaldehyde soluion.

At the end of this period, the formaldehyde bath is discarded and replaced by a fresh bath at a ratio of 25 of water to 1 of wool, containing The material is then rinsed and neutralized in a bath containing per liter of Water 10.0 cc. of 35 B. sodium bisulfite solution 10.0 grams of soda ash or 28% aqua ammonia.

Comparative testin of the abrasion resistance and tensile strength of the untreated starting material and the material treated as described above, carried out under equal conditions, have Example VI.50 grams of an air-dried woolen fabric are immersed for 30 to 60 minutes at 20-25 C. ina bath containing per liter of water 30-40 cc. of an aqueous solution of sodium N- chlor/N,N-dichlo-rsulfamate assaying 7.0% to 8.5% of electropositive chlorine 1.0 gm. of sodium propylnaphthalene sulfonate (as a wetting agent) 8 cc. of 66 B. sulfuric acid 20-30 cc. of 37% aqueous formaldehyde solution.

The woolen material is then removed from the bath, rinsed with water and neutralized with a solution containing per liter of water 20.0 cc. of 28% aqua ammonia 5.0 grams of sodium thiosulfate.

as follows:

Tensile strength Abrasion resistance warp filler l Untreated material 2, 450 60. 5 42. 5 2 Material chlorinated in the presence of formaldehyde 3, 800 63. 39. 3 Material chlorinated in the absence of formaldehyde 3, 200 28. 5 11.5

Example VII.50 grams of an air-dried woolen fabric are immersed for 30 to 60 minutes at 50 C. in a bath containing per liter of water:

30-40 cc. of an aqueous solution of sodium N chlor/N,N-dichlorsulfamate assaying 7.0% to 8.5% of electropositive chlorine 1.0 gm. of sodium propylnaphthalene sulfonate (as a wetting agent) 8 gm. of 66 .B. sulfuric acid 20.0-30.0 cc. of 37% aqueous formaldehyde solution.

The woolen material is then removed from the bath. rinsed with water and neutralized with a solution containing per liter of water 20.0 cc. of 28% aqua ammonia 5.0 grams of sodium thiosulfate.

After rinsing the material again, and, if desired, treating with a dilute soap solution, it is dried.

We have found that under the above described conditions decomposition of sodium monoand dichlorsulfamate and chlorination of wool take place rather slowly, and, therefore, our process acts mildly on the fibers and no undesired secondary effects occur. After removal of the wool, the bath still contains formaldehyde and active chlorine. In spite of their acid character, our chlorinating solutions do not adversely affect cotton fabrics in any way. We have found, for example, that if fabrics consisting of a mixture of cotton and woolen fibers are treated in accordance with our present invention, the cotton fibers of the fabric retain their full tensile strength. Furthermore, washing tests have shown that woolen goods treated according to our invention show a shrinkage of only 1% to 2%.

We have also found that the addition to the bath of a chlorosulfamate solution containing about 7.0 to 8.5% of active chlorine, and the use of formaldehyde in the amounts stated in the above examples, are necessary for obtaining the above described favorable effectsin our invention. These amounts represent a moderate excess of the reagents over that amount required for chlorination. .If the active chlorine content is substantially lower than scribed in our examples, the woolen goods treated may exhibit undesirable felting and shrinking properties, while an increased amount of chlorine in the bath may injure the fibers. The periods of treatment stated in our examples (30 to 60 minutes) have proved to give satisfactory results, but our invention is not limited, in any way to these reaction conditions.

The following tests were conducted to determine the best conditions for this process with woolen fabrics. Seven swatches with' a. total weight of 287 grams were prepared. Each swatch had a weight of 41 grams and was marked at intervals of 12 inches to measure the shrinkage. The chlorinating solution used was a solution of sodium N-chlorsulfamate/NN dichlorsulfamate assaying 7.5% available chlorine.

These seven samples (287 grams) were pretreated together for thirty minutes in a bath of the following composition at room temperature, 20-25 C. The weight of the fabric in proportion to that of the liquid was in a ratio of 1:25.

7 liters water. I

120 cc. 37% formaldehyde solution 6 grams Alronol 90 as a wetting agent.

After this pretreatment, the pieces were taken out of the formaldehyde bath, separated, and each swatch, without squeezing, was treated for one hour at room temperature, 2025 C., in baths of different compositions as described in the following seven trials, The ratio of material treated to the solution in this bath is 1 to 20, but

it was found advisable to increase the ratio to 1 to 30 in order to decrease the chlorine concentration per liter so as to avoid the danger of attacking the fibers. Th quantity of active chlorine itself has to be based on the weight of the woolen material:

' The following table .shows the quantity of Cl for 100 grams woolen material used for trials 1 to 7, the quantity of C1 consumed by each of the swatches, and the quantity of Cl remaining in the bath:

Volume Consumed Remaining C1 C1 01 Per cent Per cent Per cent After one hour's treatment in the chlorinatin: bath, the swatches were rinsed with water for 1 minutes and treated in a neutralized solution 0 sodium bisulflte plus a. small excess of soda as to remove the chloramines from the fibers.

The pieces are then rinsed and neutralized, an then rinsed and soaped at 30 C. All the sampli are non-felting, but the higher the Cl concentra tion, the less the loss on yardage as the followin table shows. This figure will vary in accordam that of the bath dewith the quality of the goods treated. The no! treated blanket material used showed, after washing, a loss (shrinkage) of 10%:

Measure Original alter Loss Percentage Mme Processing Inches Inches Inches 1 12 10 345 1549 10. 4 12 10 1910 10.4 12 10 540 His 9. 9 12 10 194s 9. 9 12 10 545 1346 9, 6 12 10 940 134a 9. 4 12 10 545 13ft 9. 6

Tensile strength Warp Filler Untreated material 50. 6 137. Trial 1 55.0 145. 0 Trial 2 55.0 145. 0 Trial 1, 3 55. 0 145. 0 Trial 4 55, 0 146. 0 Trial 55.0 144. 0 Trial 6-- 55. 0 145, 0 Trial 7 56.0 145.0

Having described our invention, what we claim and desire to protect by Letters Patent is:

1. A process for chlorinating wool and other keratinous textile fibers, which comprises treatment of said fibers with a compound selected from the group consisting of formaldehyde and formaldehyde yielding compounds, and treatment of said fibers with a compound selected from the group consisting of compounds corresponding to the general formula and Water-soluble salts thereof wherein x is selected from the group consisting of hydrogen and chlorine, said treatments being effected simultaneously.

3. A process for chlorinating wool and other keratinous fibers, which comprises treatment of said fibers with a compound selected from the group consisting of formaldehyde and formaldehyde yielding compounds, and subsequent treatment of said fibers with a compound selected from 1.0 the group consisting 01 compounds corresponding to the general formula ment of said fibers with a compound selected from the group consisting of formaldehyde and formaldehyde yielding compounds, and treatment of said fibers with a chlorinating agent consisting of an aqueous solution of the reaction product of a member of the group consisting of sulfamic acid and salts of sulfamic acid with a member of the group consisting of the salts of hypochlorous acid.

6. A process for chlorinating wool and other keratinous textile fibers, which comprises treatment of said fibers in aqueous solution with formaldehyde and simultaneous treatment of said fibers with a chlorinating agent consistin of an acid aqueous solution of the reaction product of a member of the group consisting of sulfamic acid and salts of sulfamic acid with a member of the group consisting of the salts of hypochlorous acid.

7. A process for chlorinating wool and other keratinous textile fibers, which comprises treatment of said fibers in aqueous solution with formaldehyde and subsequent treatment of said fibers with a chlorinating agent consisting of an acid aqueous solution of the reaction product of a member of the group consisting of sulfamic acid and salts of sulfamic acid with a member of the group consisting of the salts of hypochlorous acid.

JONAS KAMLET. MARK WEISBERG. LEO BEER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'EN'IS Germany Jan. 29, 1938