US2555277A - Composition for shrinkproofing and mothproofing woolen textiles - Google Patents

Description

Patented May 29 1951 UNITED STATES COMPOSITION FOR SHRINKPROOFING AND MOTHPROOFING WOOLEN TEXTILES stir OFFICE No Drawing. Application August 13, 1945, Serial No. 610,665

1 Claim.

This invention relates to the finishing of woolen textiles such as woolen yarns and cloth, raw wool and the like, as well as Wool-containing textiles in which the wool is blended with other fibres such as the cellulosic fibres. The invention includes the application to woolen textilesof novel finishing compositions capable of imparting theretocombined shrinkage control and insecticidal properties.

It has been the practice for many years to apply mothproofing or insecticidal materials to woolen textiles. For this purpose the inorganic and organic fluorides and silicofluorides are in Wide commercial usage. One important object of the present invention is the provision of novel textile finishing compositions containing fluorides in combination with a resinous binder which will impart laundry-resistance to the treated cloth, so that the mothproofing agent is not rapidly removed by laundering.

In addition to the remarkable improvements in retention and laundry-resistance of the finishes imparted by the compositions of our invention, another important advantage is obtained. This is an effective control of shrinkage of the woolen textiles during laundering. By employing as a laundry-resistant binder for aqueous dispersible fluorides a resin which also serves to inhibit or materially reduce the shrinkage of the woolen textiles upon laundering, the

process of our invention produces washable woolen textiles that retain their dimension stability and insecticidal properties even after they have'been laundered a number of times.

It has previously been proposed to control the shrinkage of Woolen textile materials by impregnating them with a solution or dispersion of a water-dispersible alkylated or alcohol-reacted methylol melamine followed by drying the impregnated textiles and heating them for a short time in order to cure the resin to a water-insoluble condition. This method of treatment is described in U. S. Reissue Patent No. 22,566, and is now in wide commercial use. We have found, however, that mothproofin properties can also be imparted to woolen textiles finished by this method, simply by incorporating suit- ."able quantities of a fluoride in the textile-finishmetal, 1. e. the alkali and alkali earth metals such as sodium fluoride, calcium fluoride, or silicofluorides such as sodium silicofluoride or triethanolamine silicofluoride.

By first dispersing the fluorides used in practicing our invention in the melamine resin-containing bath, we obtain several important ad vantages in addition to those pointed out above. One dimculty ordinarily encountered in the application of fluorides to textiles is the lack of penetration of the mothproofing agent into the textile fibres. This difliculty is completely absent in the process of our invention, for the solution of alkylated melamine-formaldehyde resin containing the fluoride penetrates the individual woolen fibres and carries with it the dissolved or suspended fluoride. Upon drying the impregnated textiles the fluoride remains suspended in the resin, and when the latter is insolubilized by curing the fluoride is held in a wash-fast condition. Woolen textiles can therefore be impregnated uniformly with any desired amounts of inorganic or organic fluorides by the process of our invention.

Any desired quantities of alkylated methylol melamine and of fluoride may be applied by the process of our invention. Ordinarily the alkylated methylol melamine is applied in quantities of about 2-15%, based on the dry weight of the woolen textiles, the maximum quantity being about 20%. Ordinarily the fluoride is applied in amounts of about 05-10%, based on the dry weight of the textiles. The fluoride may be soluble in the textile-finishing solution, as when sodium or potassium fluoride or triethanolamine silicofiuoride is used, or it may be a waterinsoluble fluoride such as calcium, barium or strontium fluoride or silicofluoride.

Suitable alkylated methylol melamines are ethylated or ethanol-reacted trimethylol melamine and butylated trimethylol melamine, preferably applied from aqueous solutions containing organic solvents, but the preferred resinous material is water-soluble methylated methylol melamine. This material is prepared by the following process. I

One mol of melamine is mixed with 3.3 mole of aqueous 37% formaldehyde previously adjusted to a pH of approximately 8.0, the temperature being aised to 70" C. and maintained at this point until a clear solution is obtained. The solution is then immediately cooled and allowed to set and the mass is broken into small pieces and dried by circulating warm air at a temperature not exceeding 55 C. The resulting 'mately 9.0.

dried powder is alkylated by admixture with twice its Weight of 95% methanol containing 0.5% of oxalic acid crystals, based on the weight of the methylol melamine. The mixture is heated to 70 C. and held at this temperature for approximately minutes, or until a clear solution is obtained, whereupon it is immediately neutralized by the addition of sufiicient sodium hydroxide solution to raise the pH to approxi- The neutralized reaction mixture is then evaporated to 80% solids under reduced pressure so that the temperature does not rise above 50 C.

The textile-finishing compositions of the present invention contain the alkylated methylol melamine dissolved therein to a strength roughly equivalent to the percent of resin desired in the textiles together with the amonut of fluoride desired for insecticidal purposes. When a watersoluble fluoride such as triethanclamine silicofiuoride is used, it may be added to the bath as an aqueous solution. Water-insoluble fluorides are preferably reduced to fine-particle size, as by precipitation from soluble fluorides or by grinding, and are added to the alkylated melamine resin solution as an aqueous suspension.

It is well known that a curing accelerator for the alkylated methylol melamine such, for example, as diammonium hydrogen phosphate should be used in amounts of about 3% based on the weight of the alkylated methylol melamine. Water-soluble fluorides such as triethanolamine silicoiiuoride can be used to replace this or other curing accelerators, since we have found that they will bring about an accelerated curing of the resin without interfering in any way with their insecticidal properties. This is true even when the impregnating bath is made alkaline with a volatile base such as ammonia, triethanolamine and the like. The combined insecticidal and curing accelerating properties of the water-soluble fluorides and silicofluorides, therefore, constitute another important advantage of the invention.

The following specific examples are illustrative of the results obtained in finishing woolen textiles by the process of the present invention.

Ewample 1 A textile-finishing bath was prepared by adding 15 cc. of triethanclamine silicofluoride dissolved in about 150 cc. of water to a solution of 45 grams of methylated methylol melamine, prepared as described above, in 140 cc. of water. Two 12 x 12" pieces of wool flannnel, weighing about 34.5 grams, were thoroughly wet out in the treating bath and then passed through padder roils set to retain a weight of bath solution equal to about 95% of the weight of the cloth. The pieces were air-dried at about 80 C. after which they were heated 9 minutes at 140 C. to cure the resin. One of the pieces was then subjected to five shrinkage wash tests, using the method described in the 1943 Year Book oi the American Association of Textile Chemists and Colorists, pages 223 and 226. The shrinkage of the original untreated fabric during five washings was about 40% in the warp and 40% in the filling. The treated piece showed 1.6% shrinkage in the warp and 0.8% in the filling.

The washed and unwashed treated pieces and the washed and unwashed untreated pieces were then exposed to black carpet beetle larvae for two weeks, using the method of damage evaluation based on the corrected weight of droppings as described in Soap and Sanitary Chemicals, August 1942 (vol. 18, No. 8), pages -99. The unwashed, untreated piece showed 10.5 mgs. of droppings, whereas the unwashed, treated pieces showed 0.0 mg. of droppings. The washed, untreated piece showed 21.4 mgs. of droppings, whereas the washed, treated piece showed only 2.6 mgs. of droppings.

These exposures to black carpet beetle larvae were made in comparison with other pieces of the same wool flannel treated with triethanolamine silicofluoride solutions containing no resinous binder, followed by washing. The triethanolamine silicofluoride was so completely removed by washing that there was substantially no protection against the carpet beetle larvae, and the shrinkage figure was of course substantially identical with that of the original untreated fabric.

Example 2 Other fluorides were suspended in 13 aqueous solutions of methylated methylol melamine which were then applied to wool flannnel in amounts of of its weight so that the impregnated cloth contained 13% of resin and the quantity of insecticide indicated below. The treated cloth was then evaluated by the methods described in Example 1 with the following results:

Mgs. 01 Droppings, Shrinkage,

Corrected Percent Insecticide Percent Y 5 Wash- Unwashed ings Warp F111 1 2. 4 5. 4 l 2 Calcium Fluoride 2 2. 2 2. 2 1 1. 3

5 2. 4 5. 4 0 U 0. 5 O. 4 6 l. 5 2. 5 Sodium Fluoride 2 1. l 5. 4 0. 7 1. 5 5 2. 3 6. 6 0. 5 1. 2 Sodium Silicog g fluoride 5 I 3' 5 0 0 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,566 Johnstone, J12, et a1. "Nov. 21, 1944 1,034,791 Minaefi July 5, 1927 2,197,357 Widmer et a1. Apr. 16, 1940 2,388,143 Harris Oct. 30, 1945 2,426,770 Grim Sept. 2, 1947 OTHER REFERENCES Gains et al., British Plastics, Feb. 1943, pp. 508-520, particularly page 511.