US 3397943 A
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iri'iti'ttiei 3,397,943 TREATMENT OF KER-ATlNO'US MATERIALS Claude Renault, Antony, France, assignor to Produits Chimiques Pechiney Saint-Cobain, Paris, France No Drawing. Filed Aug. 28, 1964, Ser. No. 392,940 Claims priority, application France, Sept. 20, 1963,
948,185 Claims. (Cl. 8--127.6)
This invention relates to a process of treating keratinous fibers, particularly wool, to make them nonfelting, and to reduce shrinkage. The process is applicable to all the articles which are wholly or partly composed of keratin, such as hair, combed or carded wool, filaments, sheets, knitwear, clothing and goods containing mixtures of keratinous and other materials.
Felting involves compression and adhesion of the fibers, which in many fabrics is undesirable and constitutes an imperfection. To reduce felting the prior art had recourse to chlorination, and later to the use of an N-chlorinated 1-3-5 triazine in aqueous pH-acid solution, a treatment which also reduced shrinking and was useful on wool, but was of limited utility because of poor solubility of the agent, and attack on wool fibers at higher effective concentrations of active chlorine.
The triazine treatment was an improvement over the chlorination but under strong washing conditions and long periods of treatment a wool thus treated still tends to felt, which produces serious drawbacks for certain textile articles.
It is possible to improve the resistance to felting by the treatment in acid medium noted above, by increasing the concentration of active chlorine in the bath, but that starts a degradation of the wool.
In prior applications Ser. Nos. 152,640 and 152,641 processes are described which confer an improved degree of resistance to shrinking and felting by treating kerat inous materials with aqueous solutions of alkali metal salts of N-dichloroisocyanuric acid. According to the technique of the first of those cases the treatment is carried out. in neutral medium using only a part of the active chlorine in the treatment, the solutions being used again after being recharged with the salts. According to the technique described in the other of these applications the treatment is carried out with acid aqueous solutions of the same salts at a pH near 2, compared to the 6.5 to 7 of the first case. In the latter case the baths produce a particularly interesting coefficient of use of the active chlorine which is present in the baths.
Both the said processes confer excellent resistance to felting on keratinous fibers but they require good control of. the conditions of use, and require that storage facilities be provided for partlyexhausted baths and for the baths when not in use, or that large volumes of treating baths be used.
It is an object of this invention to improve the process of preventing felting and shrinking by means of aqueous solutions containing alkali metal salts of dichloroisocyanuric acid. Another object is to improve the efficiency of such solutions and to exhaust them more com pletely.
The objects of the invention are accomplished gen erally speaking by the use of aqueous solutions of N-N- dihalogenoisocyanuric acid alkali metal salts in two steps.
The objects of the invention are accomplished generally speaking 'by a method of treating keratinous materials to reduce felting and shrinking which comprises maintaining the keratinous material in a neutral aqueous medium containing an alkali metal salt of dichloroisocyanuric acid until a substantial reduction of felting and shrinking has occurred, and thereafter maintaining the keratinous material in an aqueous acid medium contain 3,397,943 Patented Aug. 20, 1968 ing an alkali metal salt of dichloroisocyanuric acid until the reduction of felting and shrinking has been com= pleted.
I have now discovered that this can be achieved by carrying out the process much as it is carried out in the identified cases but in two steps, the first step being carried out in a bath at about neutral pH and the second portion at acid pH. This may be achieved by trans= ferring the wool from a neutral to an acid bath midway in the process, but it is preferably carried out in one bath by acidifying the bath after a substantial reduction in the active chlorine has occurred. Turning to the preferred process the pH of the bath in the first stage of treatment is at about 6-8, and during the second stage is between 1 and 4, and is preferably about 2.
The process of the invention is particularly efficient when the treatment in the neutral bath is carried out until at least half, and not over three-fourths, of the ac tive chlorine has been consumed, the residue of the active chlorine 'being utilized during the acid phase of treat- .ment. Excellent results are obtained when the bath is acidified when about two-thirds of the active chlorine has been consumed. In practice, the point of acidification is readily determined by the clock. One determines the total duration of the treatment for a particular kerat-. inous material and devotes three-fourths of that time to treatment in neutral medium, acid being added to the chosen pH so that the remainder of the treatment occurs in acid medium.
In using the process for textile materials, aqueous solutions are used in which the concentration of the alkali metal salts is such that the quantity of the active chlorine, expressed as a weight percent of the wool, is between 2 and 6%. It is also advantageous to carry out the process with the weight of wool fibers to the weight of the bath lying between 1/5 and 1/ 60, it being apparent from this range that the treatment can be carried out under concentrated or dilute conditions with efficiency. Excellent results are obtained with a total length of treatment between 20 and minutes at temperatures between 5 and 35 C., room temperature being preferable.
It is helpful to the treatment to incorporate in the bath surface active agents which reduce the surface tension of the bath. Such agents may be anionic, cationic, or nonionic. Among such agents there may be named the nonionic condensation products of ethylene oxide and lauryl alcohol.
When the surface active agent is used it should be stable in the bath and with respect to the keratinous ma terial. Those which have been named have this ability.
The treatment having been completed may be fol= lowed by the usual dechlorination to remove excess chlorine. The usual water solutions of sodium bisulphite, sodium hydrosulphite, or any other dechlorinating agent commonly used in the textile industry are satisfactory.
The process according to the invention has the advantage of regular action, and it is efiicient and effective in completing the treatment of keratinous fibers and materials with almost total consumption of the active chlorine in the bath, in fact so completely that the residual baths can often be discarded without substantial loss.
The following examples are illustrative of the invention but do not impose limitations upon the generality of what has been stated elsewhere herein.
The tests were carried out on textile materials of which one was a ribbon of combed wool, 45 m. to the kilogram, from Australia, quality /105, mean diameter 21.55 microns, and on filaments of combed wool, Nm 1/28, Merinos quality, degreased, nondyed.
The nonfelting characteristics of the wools were meas ured in the following way: From the ribbon there was measured off a length equal to 23 cm. which was sewed at each end and at each quarter of its length with a cotton thread. The distance between the extremes was 21 cm. after preparation of test pieces, the measurement being made by applying a tension of 100 grams. The test piece was immersed in a receptacle of 1000 cc. capacity con taining rubber balls and 150 cc. of an aqueous solution containing 5 g./l. of soap, 0.5 g./l. of sodium carbonate, and 2 cc./l. of an antifoaming agent having a silicone base. The receptacle was rotated at 44 r.p.m. in a water bath at 40 C. for minutes. After treatment the test piece was rinsed, wrung out and dried in the air without tension. The length was then measured at 100 grams tension.
The resistance to felting is represented by the percentage of shrinkage calculated as follows:
Percent of shrinkage= in which L is the length of the piece after the treatment. In dealing with certain types of combed wool one prepares a cord of Nm 2/28 from which are cut 18 lengths which are knotted together as continuous ribbon and subjected to the same tests. One is thus able to establish a relation between shrinkage of the ribbon of combed wool and that of the cords which are spun from the ribbon.
Example 1 The percentages herein stated are based on the weight of the material. A ribbon of combed wool was immersed in an aqueous solution having the composition: Sodium salt of dichloroisocyanuric acid yielding 3% of active chlorine; surface active agent being the condensation product of 9 moles of ethylene oxide on 1 mole of lauric alcohol, 1 g./l.; pH 7.4. After 45 minutes of treatment, 75% of the active chlorine had been consumed by the fiber; thereafter 5 cc./l. of hydrochloric acid B) were added and the pH fell to 2.5. The treatment continued for 15 minutes. The weight of the textile material treated, to the weight of the bath, was l/7. After the treatment the test pieces were dechlorinated in a solution containing 3% sodium bisulphite at 36 B then rinsed. The untreated test piece shrank 47%; the treated test piece shrank 9.5%. These results correspond on Nm 2/28 to a shrinkage of 1.9% for the treated sample and 45% for the untreated. The treated material had good hand and was not yellowed.
Example 2 W001 cords as described above were treated in aqueous solution containing the sodium salt of dichloroisocyanuric acid in sufiicient concentration to produce 2.5% of active chlorine and 1 g./l. of the surface active agent of EX- ample 1 at a pH of 6.7. After 45 minutes of treatment 70% of the active chlorine had been consumed by the fiber. 2 cc./l. of the hydrochloric acid (20 B) were added, producing a pH of 2.3. The treatment continued for 15 minutes more. The ratio of the weight of the treated material to the bath was l/ 30. After the treatment the material was dechlorinated as aforesaid and compared with the untreated sample. The untreated sample underwent a 46.6% shrinkage and the sample treated by this process only 3% shrinkage. The treated material had a soft hand and did not become yellow.
The advantages of the invention are in improved operation of the dichloroisocyanuric acid salts process, in the more perfect results obtained on the fiber, in the more complete exhaustion of the treating solution, in freedom from storage problems and the increase of apparatus involved, and in the accomplishment of the objects of the invention.
As many apparently widely different embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodimerits.
What is claimed is:
1. A method of treating keratinous materials to reduce felting and shrinking which comprises immersing the keratinous material in a substantially neutral, aqueous bath containing at least one alkali metal salt of dichloroisocyanuric acid, acidifying the bath before the treatment is complete and while the bath contains active chlorine, and completing the treatment in the acid bath.
2. A method of treating keratinous materials to reduce felting and shrinking which comprises maintaining the keratinous material in a neutral aqueous medium containing an alkali metal salt of dichloroisocyanuric acid until a substantial reduction of felting and shrinking has occurred, and thereafter maintaining the keratinous material in an aqueous acid medium containing an alkali metal salt of dichloroisocyanuric acid until the reduction of felting and shrinking has been completed.
3. The process of claim 2 in which the pH of the neutral medium is about 6 to 8, and the pH of the acid medium is about 1 to 4.
4. The process of claim 3 in which the treatment proceeds in a single bath, and which includes the step of acidifying the neutral bath after about half the active chlorine of the bath has been consumed.
5. The method of claim 1 in which the acidification is by the addition of mineral acid to a pH between about 1 and 4 and the acid is added when about 73 of the active chlorine necessary to the treatment has been consumed.
6. A method of treating keratinous materials to reduce felting and shrinking which comprises maintaining the keratinous material in a substantially neutral bath containing an alkali metal salt of dichloroisocyanuric acid until the quantity of active chlorine in the bath has been substantially reduced, acidifying the depleted bath, and continuing the treatment of the keratinous material therewith to a selected end point.
7. The method of claim 6 in which the total of alkali metal salt in the bath is between 2 and 6% of the weight of the keratinous material.
8. The method of claim 6 in which the bath contains a surface active agent.
9. The method of claim 6 in which the temperature of treatment is between about 5 and 35 C.
10. The method of claim 6 in which the duration of the neutral treatment is about A the total duration of the treatment.
References Cited UNITED STATES PATENTS 2,993,747 7/1961 Scott 8127.6 3,071,431 l/1963 Mertens et al. 8128 3,144,300 8/1964 Cosnard et al. 8127.6 3,236,585 2/1966 Chesner et al 8l27.6
FOREIGN PATENTS 219,930 l/1959 Australia.
OTHER REFERENCES Thompson, Soap and Chemical Specialties, p. 45, June 1964, 252-187.
NORMAN G. TORCHIN, Primary Examiner. J. CONNOR, Assistant Examiner.