US3625753A

US3625753A - Flame retardant for textiles

Info

Publication number: US3625753A
Authority: US
Inventors: Samuel James O'brien; Robert George Weyker
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1969-10-14
Filing date: 1969-10-14
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07

Abstract

Aqueous solutions of dimethylol dicyandiamide and phosphoric acid useful as durable finishes on cellulosic textile materials to impart flame retardance and the cellulosic textile materials treated therewith.

Description

United States Patent [72] Inventors Samuel James O'Brien Dunellen; Robert George Weyker, North Plainfleld, both 01 NJ. 21 Appl. No. 866,402 [22] Filed Oct. 14, 1969 [45] Patented Dec. 7, 1971 [73] Assignee American Cyanamid Company Stamford, Conn.

[54] FLAME RETARDANT FOR TEXTILES 5 Claims, No Drawings [52] US. Cl 117/137, 1 17/ 143 A [51] Int. Cl C09k 3/28, D06m 13/26 [50] Field of Search 117/136, 143,137;8/116,l16.2;252/8.1;106/15 F1 [56] References Cited UNITED STATES PATENTS 2,421,218 5/1947 Pollack 117/136X 2,519,388 8/1950 7 Loukomsky et a1. 117/137 X 2,530,261 11/1950 Morton et a1. 117/137 X 2,784,159 3/1957 Fluck et al.. 117/137X 2,917,408 12/1959 Goldslein et a1.. 117/137 X 3,105,773 10/1963 Frank et al 117/72 3,159,503 12/1964 Goldstein et al. 1 17/137 3,253,881 5/1966 Donahue... 106/15 X 3,459,588 8/1969 Davis 117/143 X FOREIGN PATENTS 476,043 11/1937 Great Britain 1 17/137 1,114,181 4/1962 Germany 117/137 OTHER REFERENCES O Brien, Textile Research Journal, Cyanamide...Cotton, PPs 256-266, 1 968 March). Primary Examiner-William D. Martin Assistant Examiner-Harry J. Gwinnell AttorneyCharles J. Fickey FLAME RETARDANT FOR TEXTILES This invention relates to an aqueous flame-retardant finish for cellulosic textile materials. More particularly, it relates to (1) aqueous solutions of dimethylol dicyandiamide and phosphoric acid, (2) to their use as a durable finish on cellulosic textile materials to impart flame retardancy, and (3) to the treated cellulosic textile materials.

The use of monomethylol dicyandiamide in flame-retardant finishes for cellulosic textile materials is well known. For example, U.S. Pat. No. 2,519,388, discloses its use in combination with phosphoric acid and methylol urea or a methylol melamine. The coapplication with an aminoplast resin, such as a methylol melamine, is necessary to obtain good wash durability of the flame-retardant finish. Also, monomethylol dicyandiamide is costly to manufacture. Because of insolubility in water, monomethylol dicyandiamide must be isolated and the isolation steps add considerably to the cost of the product, thus resulting in a price deterrent to the customer.

it is therefore an object of this invention to provide a flameretardant finish for cellulosic textile materials which is economical and durable to laundering.

This and other objects of the invention will become apparent as the description thereof proceeds.

it has now been discovered that a dimethylol dicyandiamide and phosphoric acid flame-retardant system does not require the coapplication of an aminoplast resin, such as a methylol melamine, in order to obtain durability of the finish on cellulosic textile materials. Furthermore, dimethylol dicyandiamide is water-soluble and can be manufactured and used in the flame-retardant finish with isolation. An added advantage of the flame-retardant finish of this invention is the relatively small strength loss sustained by the textile materials when reacted with the finish.

The dimethylol dicyandimide can be prepared by heating a mixture of dicyandiamide with two-mole equivalents of aqueous formaldehyde (fonnalin) to a temperature of about 70 C. Heating of the clear solution is continued for about l hour. The resulting aqueous solution of dimethylol dicyandiamide contains 50-60 percent solids and it can be used in the process of this invention.

The phosphoric acid used in the process of this invention is preferably ortho-phosphoric acid (H PO,). The commercial 85 percent acid is conveniently employed.

The dimethylol dicyandiamide-phosphoric acid finish can be conveniently applied to textile materials as an aqueous solution. The textile material can be treated by padding, spraying, dipping etc. The cellulosic textile material should contain at least 50 percent cellulosic fibers. By the term cellulosic fibers" is meant such fibers as cotton, regenerated cellulose (rayon), linen, jute, etc. Blends of cellulosic fibers with other cellulosic fibers or with noncellulosic fibers, both natural and synthetic, such as silk, wool, polyamide, polyesters, polyacrylonitrile, e.g., may be used.

The amount of the dimethylol dicyandiamide-phosphoric acid finish applied to the textile material should be between 30 and 45 percent based on the weight of the textile material. The amount of dimethylol dicyandiamide in the finish should be between 15 and 40 percent, preferably between 20 and 30 percent, based on the weight of the textile material, and the amount of phosphoric acid should be between 5 and 20 percent, preferably between 7.5 and percent, based on the weight of the textile material. Furthermore, the amount of dimethylol dicyandiamide and phosphoric acid in the aqueous solution will be adjusted to provide the amount of pickup on the textile material, as pointed out above, and will depend on the method of application. It is within the skill of the art to determine the amounts required in the solution.

The treated textile material is dried by any convenient means, as in an oven at from about 200 to 250 F., preferably 225 F., and is then heated at an elevated temperature to effect a cure of the finish on the textile material. A temperature between 225 F. and 400 F., preferably between 250 F. and 350 F., is recommended for the curing operation. This time required is between about 1 and 5 minutes depending on the temperature used and the weight of the fabric. If desired, the drying and curing operation can be done in one step.

The following specific examples are set forth to illustrate some embodiments of the invention and are not intended to be limitative.

EXAMPLE I Preparation of Dimethylol Dicyandiamide A mixture of 1,180 g. (14 moles) dicyandiamide and 2,330 g. of 35 percent aqueous formaldehyde (28 moles) was heated slowly to C., whereupon the mixture became clear. Heating was then continued at C. for one hour. The product contained about 55 percent solids.

EXAMPLES ll-XXlV Twenty-three aqueous pad baths were prepared containing the percentage amounts on a solid basis of dimethylol dicyandiamide (DD), product of example i, and orthophosphoric acid (11 1 0,) shown in table I.

The pad baths were applied to X80 percale by a standard padding procedure obtaining a 82 percent wet pickup. The padded fabrics were dried at 225 F. for 2 minutes and then heated at 325 F. for 3 minutes.

The durability of the fire-retardant finish to laundering was determined by repeatedly washing the fabric in an automatic washing machine using water at C. and a commercial detergent. After each washing operation, the flame resistance of the fabrics was determined by a vertical flame test according to Standard Test Method AATCC 34-1966. The washings and flame testings were continued as long as the char length of the burnt fabric was less than 6 inches. The limit of wash durability was reached when the char length was 6 inches.

The amounts of dimethylol dicyandiamide and phosphoric acid on the textile material and the durability of each finish to laundering are shown in table I.

TABLE I Pad bath compo- Trested textile material, Durability sition, percent percent OWF o1 finish Example No. of number DD HsPO DD H,PO washes 3O 15. 3 24. 6 12. 5 ll We claim:

1. A process for producing a durable flame-retardant finish on cellulosic textile materials comprising the steps of:

a. forming a coated cellulosic textile by applying a flame-retardant composition consisting essentially of an aqueous solution of dimethylol dicyandiamide and phosphoric acid to said cellulosic textile materials, wherein the amount of dimethylol dicyandiamide and phosphoric acid are in the ranges of 15 to 40 percent and 5 to 20 percent, respectively, based on the weight of the textile; and

b. heating the coated textile to dry and cure the finish thereon.

2. The process of claim 1 wherein said coated textile is subtemperature of from about 200 to 250 F. and subsequently sequently heated to a temperature from about 225 to 400 F. heated to from 250 to 350 F. to cure said finish.

3, The ro es of l im 2 h r i id temperature i f 5. A cellulosic textile material obtained by the process of about 250 to 350 F. claim 1.

4. The process of claim 1 wherein said textile is dried at a 5 t s s UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 25, 753 Date D mber 71 1971 Inventor(s) Samuel James O'Brien and Robert George Weyker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 52, "with" should read without Column 1, line 36, "dicyandimide" should read dicyandiamide Column 1, line 75, "This" should read The Signed and sealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD M.FLETGHER, JR. ROBERT GOTTSCHALK Atteating Officer Commissioner of Patents RM PC4050 USCOMM-DC 60S76-P59 U-SA GOVERNMINT PRINTING OFFICE: II" 0-8..3!

Claims

2. The process of claim 1 wherein said coated textile is subsequently heated to a temperature from about 225* to 400* F.
3. The process of claim 2 wherein said temperature is from about 250* to 350* F.
4. The process of claim 1 wherein said textile is dried at a temperature of from about 200* to 250* F. and subsequently heated to from 250* to 350* F. to cure said finish.
5. A cellulosic textile material obtained by the process of claim 1.