US3353993A - Method for imparting antistantic properties to textile materials - Google Patents

Description

United States Patent 3,353,993 METHOD FOR IMPARTING ANTlSTATIC PROPERTIES TO TEXTILE MATERIALS Tokurou Kida, Otokuni-gun, Kyoto, Shougo Matsuda and Seiichi Saito, Takatsuki-shi, Osaka, and Masaharu Yuasa, Nakagyo-ku, Kyoto, Japan, assignors to Asahi Chemical Industry Co. Ltd. and Tauabe Seiyaku Co.

Ltd., Osaka, Japan No Drawing. Filed Apr. 28, 1964, Ser. No. 363,295

Claims. (Cl. 117139.5)

ABSTRACT OF THE DISCLOSURE An antistatic treatment for synthetic fibers using as an antistatic agent aliphatic and aromatic aspartates, glutamates and their N-alkyl or acyl derivatives and alkyl 2- pyrrolidone 5 carboxylate; and a product thereof.

This invention relates to a method for imparting antistatic properties to textile materials.

Many textile materials display a tendency to collect static charges during their manufacturing operations. Garments made therefrom also collect static charges by rubbing. This tendency presents a particular difficulty in the case of synthetic fibers to the point that they cannot be handled without using some antistatic agents, and garments made therefrom can be seriously hazardous unless some antistatic agents are used. The generation of high static charges causes the fibers to fly apart, owing to mutual repulsion, and to adhere to any uncharged or oppositely charged object. This leads to many difficulties, such as decrease of operativeness, electrical shocks, spark discharges and the like. In case of garments made therefrom, static charges cause to attract dust and soil, and to give uncomfortable shocks and sparks to the wearer especially when removing the garments.

It has previously been known that textile materials can be prevented from acquiring high electric charges by allowing them to leak away in a physical manner or by applying an antistatic agent to the textile materials. Various types of such antistatic agents are known. Many of them depend on reducing the electric resistance of the textile materials so they impart antistatic properties to textile materials which tend to collect such charges. These agents must be physiologically harmless to the wearers and have no undesirable affect on the physical properties of the materials themselves. During their manufacturing operations, it is required that such agents can be employed in standard manufacturing practice with no special precautions or fear of corrosion to the equipment. It is almost impossible to satisfy all of the above mentioned requirements with any of the commercially available antistatic agents.

According to this invention, We have found that antistatic properties may be imparted to textile materials by applying thereto alphaamino carboxylic acid derivatives represented by the formulae:

R 0 0 C (CHQHCHCOOR wherein R and R represent hydrogen, aliphatic or aromatic hydrocarbon groups except both do not represent hydrogen simultaneously, R and R represent hydrogen, alkyl or acyl groups, R represents aliphatic or aromatic hydrocarbon radicals, and n represents an integer of 1 or 2.

Illustrative examples of' above-mentioned compounds are, diethyl aspartate, di-n-butyl aspartate, di-n-octyl aspartate, di-(2-ethyl-hexyl) aspartate, di-n-butyl N-acetylaspartate, di-(Z-ethylhexyl) N-acetylaspartate, dimethyl N-benzoylaspartate, di-n-butyl N-benzoyl-aspartate, dimethyl N-ethoxycarbonylaspartate, di-n-butyl N-ethoxycarbonylaspartate, diethyl, N,N-dimethylaspartate, di-nbutyl N,N-dimethylaspartate, di-(Z-ethylhexyl) N,N-dimethylaspartate, beta-n-butyl aspartate, beta-benzyl aspartate, beta-benzyl N-benzoylaspartate, diethyl glutamate, di-n-butyl glutamate, d-(Z-ethylhexyl) glutamate, di-n-butyl N-acetylglutarnate, di-(Z-ethylhexyl) N-acetyl glutamate, di-n-butyl N,N-dimethylglutamate, di-QZ-ethylhexyl) N,N dimethylglutamate, ethyl 2 pyrrolidone-S- car-boxylate, n-butyl 2-pyrrolidone-5-carboxylate, n-octyl Z-pyrrolidone-S-carboxylate and 2-ethylhexyl 2-pyrrolidone-S-carboxylate.

They may be used in any optically active or inactive forms in practicing the present invention. Most of them are relatively stable on heating and in Water or organic solvents. Although they are generally insoluble in water, they may be dissolved or dispersed in water by heating or adding surface active agents such as polyoxyethylene alkyl ether or those known as Tween and Span. Such surface active agents may be satisfactorily employed to-dissolve active ingredients without fear of loss of antistatic properties thereof. They are also soluble in many alcohols such as methanol, ethanol or'propanol and so alcoholic solutions thereof can be easily prepared.

The mixtures for use in carrying out the present invention preferably contain from about 0.05 to 5% by weight per volume of one of such compounds therein. They may be prepared by dissolving or uniformly dispersing the active ingredients in water or an organic solvent. The treating mixtures can be applied to textile materials which display a tendency to acquire static charges in any conventional manner. The usual padding, dipping or spraying techniques can be used on fibers, yarns, fabrics and the like. They may be, if desired, rendered insoluble or aflixed to the materials whereby they become fast to both washing and dry cleaning. This can be performed, for instance, by treating with resins such as polyacrylic ester, trimethylol melamine, guanidine phosphate-formaldehyde and epoxy resins. It is also possible to incorporate some known antistatic agents for use in the treatment of the invention.

After applying the mixture, the textile materials are squeezed to remove excess liquid and then dried or cured in any conventional manner. The compounds used in the present invention have many advantages for use in textile materials as an antistatic agent. They do not blemish textile materials, even upon radiation of light and heating at -a temperature below the softening point of the fiber.

They are almost harmless to the human body. As a result of toxicity test using mice, they showed LD of more than 10 mL/kg. by oral administration and 5 ml./ kg. by intraperitoneal administration. They did not show any irritating properties to skins when pure compounds and 25% solutions were applied on the neck of male rabbits. As to the effect on touch of the fabrics which is very important, almost no change can be seen between treated and untreated fabrics.

According to the invention, static charges on the fabrics can be reduced to practically negligible amounts for use in garments. The treatment of this invention can also be practiced on the textile materials during their manufacturing operations to avoid many hazards caused by static charges.

As a test of the effectiveness of the treatment, both the electric resistance and static potential of the material were measured, the latter immediately after rubbing. It has been known that the tendency to accumulate static charges may be determined by measuring the resistance of the article to be tested. It has also been known that garments are almost non-susceptible to static charges upon wearing or generated static charges can leak away therefrom if they show a resistance less than ohm/cm. But the resistance alone is not always identical to the tendency to generate static charges upon rubbing, so we have carried out the following tests.

The fabric under test is set on a cylinder having a diameter of cm. The cylinder is rotated at 700 r.p.m. As the cylinder rotates, the fabric rubs against a surface of leather. The fabric is rubbed for five minutes and the potential built up thereupon is measured with an electrometer immediately. After allowing to stand for one minute, the residual potential is also measured. According to this test, a standard cotton fabric shows an initial potential of 0.3 kv. and a residual potential of almost zero level. Since cotton fiber has been considered to be non-susceptible to static charges, it can be considered that the antistatic treatment is successful if the result obtained shows a degree almost the same as cotton fabric. Typical results obtained from the test on some untreated fabrics are shown in the following table.

TABLE I. (45% R.H. at 30 C.)

Initial potential Residual Fabric Resistance after potential (ohm/cm.) rubbing (kilovolt,

(kilovolt, 1 minute) 5 minutes) Acrylic 10 1. 1 0. 6 Polypropylene 10 2. 2 2. 0 Nylon 10 1. 2 0. 4 Polyester 10 0.3 0. 2

The invention will be illustrated by the following specific examples in which all are parts by weight unless otherwise indicated. The results of each of the following are found in Table II.

Example 1 4 Example 2 Nylon taffeta fabric was treated with a bath containing 2% by weight per volume of di-n-butyl L-aspartate in methanol as in Example 1.

Example 3 Di-n-butyl N-acetyl-L-aspartate was prepared by mixing parts of dim-butyl L-arpartate, 42 parts of acetic anhydride and 33 parts of pyridine, allowing to stand to complete the reaction and distilling the reaction mixture. A mixture of 5 parts of di-n-butyl N-acetyl-L-aspart-ate and 1 part of polyoxyethylene oleyl ether was heated at about 60 C.

To the mixture was added an amount of hot water at the same temperature with stirring until the concentration reaches to 30% by weight per volume and then cooled. The resulting mixture was diluted with cold water to the concentration of 0.5% by weight per volume. Nylon fabric was treated with the diluted mixture as in Example 1.

Example 4 A fabric made of acrylic spun yarn was treated with a bath containing 0.5% by weight per volume of di-nbutyl N-acetyl-L-aspartate in methanol as in Example 1.

Example 5 An aqueous emulsion containing 0.5% by weight per volume of di-n-butyl N-acetyl-L-aspartate and 0.1% by weight per volume of polyoxyethylene oleyl ether was prepared. An acrylic fabric was treated with the emulsion as in Example 1.

Example 6 Di-n-octyl L-aspartate was prepared by reacting 10 parts of L-aspartic acid with 75 parts of n-oct-anol as in Example 1. A nylon fabric was treated with a bath containing 0.5% by weight per volume of di-n-octyl L-aspartate as in Example 1.

Example 7 Di-n-butyl D-glutamate was prepared by saturating a mixture of 5 parts of D-glutamic acid and 30 parts of nbutanol with hydrogen chloride gas and heating the mixture. 23 parts of said ester, 9 parts of acetic anhydride and 7 parts of pyridine were mixed, allowed to stand to complete the reaction and then distilled, whereby di-nbutyl N-acetyl-D-glutamate was obtained. A fabric made of polypropylene fiber was treated with a bath containing 0.5 by weight per volume of di-n-butyl N-acetyl-D- glutamate in methanol as in Example 1.

Example 8 0.9 part of polyoxyethylene oleyl ether, 0.1 part of polyoxyethylene sorbitan mono-oleate and 5 parts of di-n-butyl N-acetyl-D-glutamate were heated at about 60 C. To the mixture was added an amount of water of the same temperature with stirring until the concentration reaches to about 30% by weight per volume and cooled. The resulting mixture was diluted to the concentration of 2% by weight per volume with cold water. A polypropylene fabric was treated with the mixture as in Example 1.

Example 9 An aqueous emulsion containing 0.5% by weight per volume of di-n-butyl N-acetyl-D-glutamate and 0.1% by weight per volume of poly-oxyethylene oleyl ether was prepared. A polyester fabric was treated with the emulsion as in Example 1.

Example Example 11 Di-(2-ethylhexyl) N-acetyl-D-glutamate was prepared by mixing 50 parts of di-(2-ethylhexyl) D-glutamate, 14 parts of acetic anhydride and 11 parts of pyridine, allowing to stand to complete the reaction and distilling. 0.9 part of polyoxyethylene oleyl ether, 0.1 part of polyoxyethylene so'rbitan mo'no-oleate and 5 parts of di-(Z-ethylhexyl) N-acetyl-D-glutamate were heated at a temperature of about 60 C. to about 70 C.

To the mixture was added an amount of water of the same temperature with stirring until the concentration reaches to about 40% by weight per volume and then cooled. The resulting mixture was diluted to the concentration of 2% by weight per volume with cold water. A nylon fabric was treated with the mixture as in Example 1.

Example 12 An aqueous emulsion containing 2% by weight per volume of di-(Z-ethylhexyl) N-acetyl-D-glutamate and 0.4% by Weight per volume of polyoxyethylene oleyl ether was prepared. A polypropylene fabric was treated with the emulsion as in Example 1.

Example 13 An acrylic fabric was treated with 0.5% by weight per volume solution of n-butyl 2-pyrrolidone-5-carboxyl'ate in methanol as in Example 1. The same treatment was repeated using polypropylene fabric and 2% by weight per volume aqueous solution of said compound. A polyester fabric was also treated with 0.5% by weight per volume aqueous solution of the same compound.

Example 14 An acrylic fabric was treated with 0.5% by weight per volume solution of Z-ethylhexyl 2-pyrrolidone-5-carboxylate in methanol as in Example 1.

Example 15 A 5% by weight per volume aqueous solution of nbutyl 2-pyrrolidone-5-carboxylate was sprayed to an acrylic fabric to give a pick up of 15% based on the weight of the fabric and then dried.

Example 16- 3 parts of di-n-butyl N-acetyl-D-glut-amate was added to 100 parts of aqueous solution of polyacrylic ester resin, and 1 part of trimethylolmelamine and 0.2 part of Z-imino-iso-propanol hydrochloride were added to the mixture.

A polyester fabric preliminarily dried at 70 C. for 2 minutes was padded through the resulting mixture as in Example 1 and cured at 140 C. for 5 minutes. The resultant fabric showed an excellent antistatic property.

Example 17 2 parts of di-n-butyl N-acetyl-D-glutamate was added to 100 parts of 2.6% aqueous solution of guanidinephosphate-formaldehyde resin, and 1 part of trimethylolmelamine was added to the mixture. Example 16 was repeated with an acrylic fabric using the resulting mixture. The resultant fabric showed an excellent antistatic property.

TABLE II Initial potential Residual Example Resistance alter potential (ohm/em.) rubbing (kilovolt, (kilovolt, 1 minute) 5 minutes) 1 See Table III for Example 13.

TABLE III Example 13 Initial potential Residual Fabric Resistance after potential (ohm/cm.) rubbing (kilovolt, (kilovolt, 1 minute) 5 minutes) Polypropylene 1X10 0. 08 0. 02 Acrylic 2X10 0. 06 0 Polyester 3X10 0. 003 0 We claim: 1. Method for imparting antistatic properties to textile materials made of synthetic fibers whch comprises applying to said materials, as an antistatic agent, a compound selected from the group consisting of:

R 0 0 C (0112),; OHCOOR ing of hydrogen and a hydrocarbon radical except that both are not hydrogen simultaneously, R and R are selected from the group consisting of hydrogen, an alkyl and an acyl radical, R is an aliphatic hydrocarbon radical and n represents an integer of 1 and 2, and drying said materials.

2. The method in accordance with claim 1, wherein said compound is applied together with a water soluble resin whereby said compound is deposited on the material to form a durable antistatic finish.

3. The method in accordance with claim 1, wherein said compound is applied to the textile materials during their manufacturing operations.

4. A method according to claim 1 wherein said R and R are C H R is acetyl, R is hydrogen, and n is 2.

5. Textile materials made of synthetic fibers having an antistatic coating thereon comprising a compound selected from the group consisting of:

R oo0-(cH2 n0H00oR and Wherein R and R are selectedfrom the group consisting of hydrogen, alkyl radical and benzyl radical except that both are hydrogen not simultaneously, R and R are selected from the group consisting of hydrogen, an alkyl and acyl radical, R is selected from the group consisting of an alkyl radical, and n is an integer of 1 and 2.

References Cited UNITED STATES PATENTS 3,212,927 10/1965 Williams 117-1395 X FOREIGN PATENTS 483,224 4/1938 Great Britain.

WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner.

Claims (1)

1. METHOD FOR IMPARTING ANTISTATIC PROPERTIES TO TEXTILE MATERIALS MADE OF SYNTHETIC FIBERS WHICH COMPRISES APPLYING TO SAID MATERIALS, AS AN ANTISTATIC AGENT, A COMPOUND SELECTED FROM THE GROUP CONSISTING OF: