US3219478A - Flameproofing of cellulosic material - Google Patents

Description

United States Patent Office 3,219,478 Patented Nov. 23, 1965 3,219,478 FLAMEPROOFING F CELLULQSIC MATERIAL George M. Wagner, Lewiston, N.Y., assignor to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of N ew York No Drawing. Filed May 14, 1962, Ser. No. 194,676 19 Claims. (Cl. 117136) This invention relates to a process for the preparation of flame-retardant cellulosic material and to the compositions produced thereby. More particularly, this invention relates to an improvement in the treatment of cellulosic textiles with a solution containing a hydroxymethylphosphonium chloride compound and a high softening point polyvinyl chloride resin.

This application is a continuation-impart of my copending application S.N. 70,387, filed November 21, 1960.

Numerous processes have been developed for treating cellulosic material such as textiles with methylol-phosphorus polymers to render the textiles flame-retardant. Such processes are exemplified by the disclosure of U.S. Patent 2,809,941, issued on October 15, 1957, to Reeves et al. When techniques such as these are employed, the treated fabric is flame-retardant when subjected to the standard char test. Under certain conditions, however, as for example after several washings of the treated cloth, the treated fabric will ignite.

In another process it has been proposed to admix the methylol-phosphorus compound disclosed by Reeves et a]. in the aforementioned patent with plasticized polyvinyl chloride resins having a softening point below about 80 C. Although mixed polymers such as these render the treated textile flame-retardant, frequent washings of the treated textile affect the flame-retardant properties of the textile. Moreover, the treated cloth has a relatively poor hand and becomes extremely stiff and boardy after repeated ironing. Additionally, when the textiles are treated with the aforesaid mixed polymers, the fibers of the textile begin to swell and remain in a swollen state after treatment, thereby significantly increasing the thickness of the cloth. This increase in thickness appears adversely to affect the hand of the treated cloth.

In my copending application S.N. 70,387, now U.S. Patent 3,054,698, issued September 18, 1962, it has been proposed to impregnate a cellulosic material with an aqueous resin dispersion containing an hydroxymethylphosphoniurn chloride compound, a water-soluble cyclic nitrogen containing compound, a water-soluble tertiary alkyl amine, urea, and a polyvinyl chloride resin having a high softening point. Although cellulosic material treated with this composition are not subject to the aforementioned difficulties, it has been found that in this impregnating bath, excessive amounts of the flame-retardant ingredients, i.e., the hydroxymethylphosphonium chloride compound and the polyvinyl chloride, must be used to obtain the desired flame retardancy. Accordingly, it is desirable to reduce the amount of these ingredients in the composition, thus reducing the cost of the composition, while still maintaining the improved properties of the impregnated material, in terms of flame retardancy and hand.

It is, therefore, an object of the present invention to provide an improved method of preparing flame-retardant cellulosic material.

A further object of the present invention is to provide novel flame-retardant cellulosic materials.

Another object of the invention is to provide a method of improving the fiame-retardance and hand of cellulosic textiles, While reducing the amount of flame-retardant constituents in the impregnating composition.

Still another object of the invention is to provide novel cellulosic textiles which retain their flame-retarding properties after frequent washings and have an improved hand even after being subjected to frequent ironing, which textiles contained significantly lesser amounts of the flameretardant constituents than are now necessary.

These and other objects of the invention will become apparent to those skilled in the art from the description of the invention which follows.

It has now been discovered that flame-retardant cellulosic materials, having improved physical properties, may be prepared by impregnating the cellulosic material with an aqueous resin dispersion containing a hydroxymethylphosphonium chloride compound, having the formula (CH OH) RPCl, where R is as defined hereinbelow, a Water-soluble cyclic nitrogen-containing compound, a water-soluble tertiary alkyl amine, urea or thiourea, a polyvinyl chloride resin having a high softening point, and antimony oxide, and then drying and curing the resulting resin impregnated cellulosic material. When a cellulosic textile is treated in accordance with the instant invention, the resin impregnated textile has a markedly improved hand, tear strength, tensile strength, and flame retarding properties, when compared with textiles treated with resin compounds by the techniques of the prior art. Moreover, these improved properties in the impregnated textile are achieved with the use of lesser amounts of the polyvinyl chloride and the hydroxymethylphosphonium chloride compound than can presently be used in the prior art techniques. A

More specifically, the aforesaid constituents used in preparing the aqueous resin dispersion or emulsion of the present invention are preferably present in amounts within the following ranges, which ranges are given in percent by weight. Hydroxymethylphosphonium chloride compounds 620%, water-soluble cyclic nitrogen-containing compound 3-12%, Water soluble tertiary amine 14% urea or thiourea 3-12%, high softening point polyvinyl chloride resin (dry basis) 3-15 antimony oxide 3l5%, water 45-80%.

A specifically preferred composition for the aqueous resin dispersion of the present invention is as follows:

Percent by weight Antimony oxide 8.0

Hydroxymethylphosphonium chloride compounds suitable for use in the instant invention are those Watersoluble compounds having the formula (CH OH) RPCl, where R is selected from the group consisting of hydroxymethyl, lower alkyls having between about one and eight carbon atoms and chlorinated lower alkyls having between about one and about eight carbon atoms. Typical examples of suitable water-soluble hydroxymethylphoy phonium compounds are tetrakis(hydroxymethyl)phosphonium chloride, tris(hydroxymethyl)methyl phosphonium chloride, tris(hydroxymethyl)ethyl phosphonium chloride, tris(hydroxymethyl)butylphosphonium chloride, tris(hydroxymethyl)octy1 phosphonium chloride,tris (hydroxymethyl)chlorooctyl phosphonium chloride, and mixtures thereof. Of these, the preferred phosphonium hydroxyrnethyl is tetrakis(hydroxymethyl) phosphonium chloride, and for this reason, hereinafter primary reference will be made to this compound. The phosphonium chloride used may be in the monomer form or in a partially polymerized form, the only requirement being that Whatever form it is in, it is still Water-soluble.

In this regard, for example, tetrakis(hydroxymethyl) phosphonium chloride may be heated to effect a partial polymerization before dissolving it in the aqueous solution.

Water-soluble cyclic nitrogen-containing compounds suitable for use in the present invention include triazines and dimethylol cyclic alkylene ureas. Typical examples of suitable triazines include the methylol melamines such as mono-, di-, and trimethylol melamine, modified methylol melamines such as the trimethylether of trimethylol melamine, triazones, and mixtures thereof. Typical examples of suitable cyclic alkylene ureas include dimethylol ethylene urea and dimethylol propylene urea. Of these, trimethylol melamine is preferred and for this reason, hereinafter primary reference will be made to this compound.

Water-soluble tertiary amines which are suitable for use in the present invention include triethylamine, triethanolamine, triisopropanolamine, and the like. Of these, the triethanolamine is specifically preferred.

Polyvinyl chloride resins suitable for use in the novel fiameproofing composition of the present invention are polyvinyl chloride resins having a softening point between about 170 and about 200 C. The polyvinyl chloride resin used is, preferably, unplasticized and contains a major amount of vinyl chloride. If desired, these resins may be copolymers of a vinyl chloride with other monomers such as vinylacetate, acrylates, vinylidene chloride and the like. The proportion of these ingredients in the polyvinyl chloride resin, however, should be less than those proportions which will reduce the softening point of the resulting resin to below about 160 C. Preferably the polyvinyl chloride resin is employed as an aqueous dispersion or emulsion containing between about 45 and 55% by weight of polyvinyl chloride resin.

Urea is also employed in the compound of the flameproofing composition, in the proportions which have been set forth hereinabove. Alternatively, instead of urea, thiourea may be used with equally good results. Any commercial grade of either urea or thiourea may be used satisfactorily in the present componsition. Because of its lower cost, however, it has generally been found to be preferable to use urea, rather than thiourea.

Any commercially available antimony oxide may be used in the composition of the present invention. It is preferable, however, that the antimony oxide used be a pigment grade. Additionally, excellent results have been obtained by using a water-ground dispersion of antimony oxide, as for example, a dispersion containing about 80% by weight of antimony oxide. Accordingly, the use of such a dispersion is preferred in the practice of the present invention.

Any cellulosic material such as cotton, rayon, ramie, jute, paper, cardboard and the like may be treated in accordance with the instant invention. The invention is, however, particularly effective when applied to the treatment of cellulosic textiles, inasmuch as the treated textiles have a markedly improved hand as Well as flame retarding properties.

In preparing the aqueous dispersion or emulsion for use in the present invention, the various constituents are admixed with sufiicient water to provide an aqueous resin dispersion or emulsion containing between about 30 and about 60% by weight of total solids. Preferably, the resin dispersions should contain between about 40 and about 50% total solids by weight. The term total solids as used throughout the specification and claims, is intended to include both the solids that are dissolved in the aqueous component as well as those solids which are colloidally dispersed, or otherwise dispersed, in the aqueous dispersion or emulsion. The term dispersion, as used throughout the specification and claims, is intended to include the dispersion and/or emulsion that results from admixing the above defined hydroxymethylphosphonium chloride compound, the cyclic nitrogencontaining compound, the water-soluble tertiary alkyl amine, the urea or thiourea, the polyvinyl chloride resin, the antimony oxide and water in the proportions as set forth hereinabove. Lesser proportions of the aforesaid components may be employed so long as the concentration of total solid in the aqueous dispersion is sufficient to provide an adequate resin add-on for the cellulosic material being treated.

The cellulosic material to be impregnated by the process of the present invention is impregnated by padding, by spraying, by rolling, or by any other impregnating techniques well known to those skilled in the art. It is preferred to immerse the cellulosic material in the aqueous dispersion until the cellulosic material is completely saturated. Thereafter, the cellulosic material is preferably passed through squeeze rolls to remove the resin dispersion in excess of that amount necessary to saturate the cellulosic material.

The saturated cellulosic material is then subjected to conditions of temperature and time sufficient to effect drying of the material and curing of the resin impregnated therein. The drying and curing can be effected by any commercially feasible techniques. For example, drying of the cellulosic material can be eflfected in a conventional forced hot air oven, wherein the saturated cellulosic material i heated at a temperature between about and about C. for between about /2 to 2 minutes. Curing of the thus dried cellulosic material can then be effected in the same apparatus by heating the dried material to a temperature of between about 140 and C. for between about 1 and about 2 minutes. If desired, curing of the dry, treated cellulosic material can be effected in an infrared oven at a temperature between about 500 and about 700 F., for a period between about 5 and about 12 seconds.

After curing, the resin impregnated cellulosic material is preferably subjected to a scouring step in order to remove any unpolymerized resin. For example, scouring can be effected by immersing the cured cellulosic material in an aqueous solution containing about 0.2 percent by weight of soap and about 0.2 percent by weight of sodium carbonate. After immersing the resin impregnated material in the solution, it is then dried in the manner as set forth hereinabove.

The amount of resin added to the cellulosic material by the aforementioned technique is generally between about fifteen and about thirty-five percent by weight of the cellulosic material, with an amount between about twenty-four and about twenty-eight percent weight of the cellulosic material being specifically preferred. This amount of resin is referred to throughout the specification and claims as the resin add-on. The resin formed on the cellulosic material by the present process is the reaction product of the non-aqueous components of the aqueous resin dispersion, i.e., the hydroxymethylphosphonium chloride compound, the cyclic nitrogen-containing compound, the water-soluble tertiary alkyl amine, the urea or thiourea, the high softening point polyvinyl chloride resin, and the antimony oxide. When the aqueous resin dispersed contains the resin forming ingredients in the proportions as set forth hereinabove, the resulting resin which impregnates the cellulosic material is a reaction product containing these constituents in the following proportions: hydroxymethylphosphonium chloride compound 1040% by weight of the resin forming ingredients, cyclic nitrogen-containing compound 525% by weight of the resin forming ingredients, water-soluble tertiary alkyl amine 1-15% by weight of the resin forming ingredients, urea or thiourea 1-15% by weight of the resin forming ingredients, the high softening point polyvinyl chloride resin 10-30% by weight of the resin forming ingredients, antimony oxide 1030% by weight of the resin forming ingredients.

Cellulosic materials treated in accordance with the instant invention are found to have improved flame-retarding properties, which properties are retained even after the treated cellulosic material is contacted with water or other solvents. Moreover, when cullulosic textiles are treated in accordance with the instant invention, the textile is not only flame-retardant but also has a markedly improved hand, i.e., the textile is soft and flexible. Additionally, it is found that the desirable properties are retained even after repeated washings and ironings.

In order that those skilled in the art may better understand the method of the present invention and the manner in which it may be practiced, the following specific examples are given.

Example I A series of aqueous dispersions are prepared using the following components in the following proportions:

* Softening point of polyvinylehioride is 180 0.

Four lengths of 3.3 yards per pound broadcloth are then padded through each of the above dispersions, one length in each dispersion, and are then passed through squeeze rolls where they are squeezed at a pressure of 60 psi. The wet pickup in each instance is found to be about 96%. The fabric impregnated with each of the above dispersions is then dried at 200 F. for a period of two minutes and then cured for three minutes at a temperature of 280 F. The thus cured fabric is then scoured by immersing it in an aqueous solution containing 2.0% of a non-ionic detergent, 2% of soda ash and 4% of sodium perborate, based on the untreated weight of the fabric. The temperature of the scouring solution is maintained at about 180 F. After scouring, the fabric is dried.

The thus obtained resin treated fabric is then subjected to the standard char test. The char test is carried out in accordance with the American Association of Textile Chemists and Colorists, Test AATC 34-1952. In this test, a strip of cloth to be tested is secured on each of its long sides in a vertical position, having an exposed area of approximately inches by 2 /4 inches. A bunson burner is positioned below the bottom of the cloth so that the top of the burner is about three-quarters of an an inch from the cloth. The burner produces a flame which is about one and one-half inches high. The flame is produced by burning natural gas in the absence of air. The cloth is exposed to the flame for a period of twelve seconds and the flame is then turned off. The cloth is then removed from the securing means and a weight is attached to one side of the char, the weight being equivalent to ten percent of the tear strength of the cloth. The opposite side of the cloth is then pulled to produce a tear along the char. The length of the tear is then measured to determine the char in inches. Using this procedure, with the fabric obtained by impregnating with the above four dispersions, the following results are obtained.

Char length, inches:

A 4.7 B .3 C 8.0 D Burns From the above results it is seen that when the antimony oxide is omitted from the impregnating composition, the amount of the other components remaining the same, the resulting fabric is not fiame retardant, but rather, burns freely. This test shows the criticality of the antimony oxide in the present composition.

Example 2 A pad-bath is prepared by admixing the following constituents in the indicated amounts: Water, 47 gallons; trimethylolmelamine, 53 pounds; triethanolamine, 26 pounds; tetrakis(hydroxymethyl)phosphonium chloride solution), 87 pounds; urea, 26 pounds; non-ionic wetting agent, three pounds; polyvinylchloride latex having a melding point of 180 C., 126 pounds; antimony oxide, 69 pounds. The resulting pad-bath has a total volume of 80 gallons and contains 40% by weight solids.

Eight hundred yards of a 1.2 yard per pound drapery fabric is impregnated in the pad-bath and passed through squeeze rolls set at 4.6 tons pressure. The wet pickup in the fabric is 72%. The fabric is then dried in a tenter frame at 300 F. for forty seconds. The thus dried fabric is then cured in the same tenter frame at 375 F. for forty seconds. The thus cured fabric is then scoured in a six-box open width washer, using a scouring solution of Example 1 in the first two boxes and clear water in the last four boxes. The fabric is then dried, steamed, and framed to the desired width. The fabric is found to have a resin add-on of 23%. The tensile strength of the treated fabric, as determined in accordance with Federal Specification CCC-Tl91b#5100, using a Scott tensile tester, is 72 pounds as compared to a tensile strength of 75 pounds for the untreated fabric.

The resin impregnated fabric is then subjected to the standard char test and is found to have a char length of 3.3 inches.

Additional samples of the treated fabric are boiled for a period of 45 minutes in an aqueous solution containing 0.25% soda ash and 0.25% soap. Following the 45 minute boiling time, the samples are rinsed in clear water at a temperature of F. for a period of fifteen minutes. This boiling and rinsing cycle is repeated for a total of ten times with the fabric samples being dried after each five cycles. When ten cycles have been completed, the dried fabric is once again subjected to the standard char test and gives a char length of 4.10 inches.

Example 3 A pad bath is made by admixing the following constituents in the amounts indicated: Water, 34 gallons; trimethylolmelamine, 42 pounds; triethanolarnine, 21 pounds; tetrakis (hydroxymethyl phosphonium chloride (80% solution), 69 pounds; urea, 21 pounds; non-ionic Wetting agent, two pounds: polyvinyl chloride latex having a softening point of C, 101 pounds; antimony oxide, 55 pounds. These constituents make up a 60 gallon pad bath containing 42% by weight solids.

Four hundred yards of a 54 wide, 1.58 yd. per pound drapery fabric is impregnated in this pad bath and then passed through squeeze rolls set at 60' p.s.i. The wet pickup of the fabric is 87%. The fabric is then dried at 300 F. for a period of fifteen seconds and then cured at 290 F. for three minutes. The thus cured fabric is then scoured in a jig, using the scouring solution as set forth in Example 2. After scouring, the fabric is water rinsed and then partially dried on cans, and finally dried completely on a tenter frame. The resin add-on in the thus dried fabric is found to be 23%. The tensile strength of the treated fiber is found to be 65 pounds, as compared to a tensile strength of 80 pounds for an untreated fabric.

The resin impregnated fabric is subjected to standard char test and is found to have a char length of 3.3". Thereafter, other samples of the fabric are subjected to fifteen boiling cycles, and then subjected to the standard char test. The results obtained show a char length for the impregnated fabric, after the boiling cycles, of 5.0 inches. Both the hand and drape of the fabric is determined to be good both before and after the fabric is subjected to the boiling cycles.

While there have been described various embodiments of the invention, the method and products described are not intended to be understood as limiting the scope of the invention, as it is realized that changes therewithin are possible and it is further intended that each element recited in any of the following claims is to be understood as referring to all equivalent elements for accomplishing substantially the same results in substantially the same or equivalent manner, it being intended to cover the invention broadly in whatever form its principle may be utilized.

I claim:

1. A process for preparing a flame-retardant cellulosic material which comprises impregnating the cellulosic material to be treated with an aqueous dispersion of a hydroxymethylphosphonium chloride compound, a water-soluble cyclic nitrogen-containing compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, a water-soluble tertiary lower alkyl amine, a compound selected from the group consisting of thiourea and urea, a polyvinyl chloride resin having a softening point between about 170 and about 200 C., and antimony oxide, and drying and curing the cellulosic material.

2. A process for preparing a flame-retardant, cellulosic material which comprises impregnating the cellulosic material to be treated with an aqueous dispersion containing between about 45 and about 80% by weight of water, between about six and about 20% by weight of a hydroxymethylphosphonium chloride compound, between about three and about 12% by weight of a watersoluble cyclic nitrogen-containing compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, between about one and about four percent by weight of a water-soluble tertiary lower alkyl amine, between about three and about 12% by weight of a compound selected from the group consisting of urea and thiourea, between about 3 and about 15% by weight of a polyvinyl chloride resin having a softening point between about 170-200 C., and between about three and about 15% by weight of antimony oxide, and drying and curing the treated cellulosic material.

3. The process as claimed in claim 2 wherein the hydroxymethylphosphonium chloride compound is tetrakis(hydroxymethyl) phosphonium chloride.

4. The process as claimed in claim 2 wherein the cellulosic material is a cellulosic textile.

5. The process as claimed in claim 2 where the resin add-on of the treated cellulosic material, after curing, is between about 15 and about 35 by weight of the cellulosic material.

6. A process for preparing a flexible, flame-retardant cellulosic textile which comprises impregnating the cellulosic textile to be treated with an aqueous dispersion containing between 45 and about 80% by weight of water, between about 6 and about 20% by weight of tetrakis(hydroxymethyl)phosphonium chloride, between about one and about four percent by weight of triethanolamine, between about three and about 12% by weight of trimethylolmelamine, between about three and about 12% by weight of urea, between about three and about 15% by weight of a polyvinyl chloride resin having a softening point between about 170 and about 200 C., and between about three and about 15% by weight of antimony oxide, and drying and curing the treated cellulosic material.

7. The process as claimed in claim 6 wherein the resin add-n of the treated cellulosic material after curing is between about 15 and about 35% by weight of the cel lulosic textile.

8. A flame-retardant cellulosic material comprised of cellulosic material impregnated with a resinous material .comprising the reaction product of a hydroxymethylphosphonium chloride compound, a water-soluble cyclic nitrogen-containing compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, a water-soluble tertiary lower alkyl amine, a compound selected from the group consisting of urea and thiourea, a polyvinyl chloride resin having a softening point between about and about 200 C., and antimony oxide.

9. A flame-retardant cellulosic material comprised of a cellulosic material impregnated with a resinous material, said resinous material being the reaction product formed from resin forming ingredients comprised of a hydroxymethylphosphonium chloride compound in an amount equivalent to between about 10 and about 40% by weight of the resin forming ingredient, a water-soluble cyclic nitrogen-containing compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, in an amount equivalent to about 5 and about 25% by weight of the resin forming ingredients,

a water-soluble tertiary lower alkyl amine in-anamount equivalent to between about one and about 15% by weight of the resin forming ingredients, a compound selected from the group consisting of urea and thiourea in an amount equivalent to between about one and about 15 by weight of the resin forming ingredients, a polyvinyl chloride resin having a softening point between about 170 and about 200 C. in an amount equivalent to between about 10 and about 30% by weight of the resin forming ingredients, and antimony oxide in an amount equivalent to between about 10 and about 30% by weight of the resin forming ingredients.

10. A flame-retardant cellulosic material as claimed in claim 9 wherein the hydroxymethylphosphonium chloride compound is tetrakis(hydroxymethyl)phosphonium chloride.

11. The flame-retardant cellulosic material as claimed in claim 9 wherein the cellulosic material is a cellulosic textile.

12. The flame-retardant cellulosic material as claimed in claim 9 where in the resin add-on is between about 15 and about 35% by weight of the cellulosic material.

13. A flame-retardant cellulosic material comprised of a cellulosic material impregnated with a resinous material, said resinous material being the reaction product formed from resin forming ingredients comprised of tetrakis(hydroxymethyl)phosphonium chloride in an amount equivalent to between about 10 and about 40% by weight of the resin forming ingredients, trimethylolmelamine in an amount equivalent to between about 5 and about 25% by weight of the resin forming ingredients, triethanolamine in an amount equivalent to between about one and about 15% by weight of the resin forming ingredients, urea in an amount equivalent to between about one and about 15% by weight of the resin forming ingredients, a polyvinyl chloride resin having a softening point of between about 170 and about 200 C. in an amount equivalent to between about 10 and about 30% by weight of the resin forming ingredients, and antimony oxide in an amount equivalent to between about 10 and about 30% by weight of the resin forming ingredients.

14. The flame-retardant cellulosic material is claimed in claim 13 wherein the cellulosic material is a cellulosic textile.

15. The flame-retardant cellulosic material as claimed in claim 13 wherein the resin-add-on is between about 15 and about 35 by weight of the cellulosic material.

16. A flame-retardant cellulosic textile comprised of a cellulosic textile impregnated with a resinous material, said resinous material being the reaction product formed from resin forming ingredients comprised of tetrakis(hydroxymethyl)phosphonium chloride in an amount equivalent to between about 10 and about 40% by weight of the resin forming ingredients, trimethylolmelamine in an amount equivalent to between about 5 and about 25% by weight of the resin forming ingredients, triethanolamine in an amount equivalent to between about 1 and about 15% by weight of the resin forming ingredients, urea in an amount equivalent to between about 1 and about 15% by weight of the resin forming ingredients, a polyvinyl chloride resin having a softening point of between about 170 and about 200 C., in an amount equivalent to between about and about 30% by weight of the resin forming ingredients, and antimony oxide in an amount equivalent between 10 and about 30% by weight of the resin forming ingredients, wherein the resin addon is between about 24 and about 28% by weight of the flame-retardant cellulosic material.

17. A cellulosic material treating composition comprised of hydroxymethylphosphonium chloride compound, a water-soluble cyclic nitrogen-containing compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, a water-soluble tertiary lower alkyl amine, a compound selected from the group comprising of thiourea and urea, a polyvinyl chloride resin having a softening point between about 170 and about 200 C., antimony oxide, and water.

18. A cellulosic material treating composition comprising an aqueous dispersion containing between about 6 and about 20% by weight of hydroxymethylphosphonium chloride compound, between three and about 12 percent by weight of a water-soluble cyclic nitrogencontaining compound selected from the group consisting of triazine and dimethylol cyclic alkylene ureas, between about one and about four percent by weight of a water-soluble tertiary lower alkyl amine, between about three and about twelve percent by weight of a compound selected from the group consisting of urea and thiourea, between about 3 and about 15% by weight of a polyvinyl chloride resin having a softening point between about 170 and about 200 C., between about three and about fifteen percent by weight of antimony oxide and between about forty-five and about eighty percent by weight of water.

19. A textile treating composition comprised of an aqueous dispersion containing between about six and about twenty percent by Weight of tetrakis(hydroxymethyl)phosphonium chloride, between about one and about four percent by weight of triethanolamine, between about three and about twelve percent by weight of trimethylolmelamine, between about three and about twelve percent by weight of urea, between about three and about 15 by weight of a polyvinyl chloride resin having a softening point of between about and about 200 C., between about three and about fifteen percent by weight of antimony oxide, between about forty-five and about eighty percent by weight of water.

References Cited by the Examiner UNITED STATES PATENTS 3,054,698 9/1962 Wagner 117-136 FOREIGN PATENTS 711,699 7/ 1954 Great Britain.

755,958 8/ 1956 Great Britain.

784,171 10/ 1957 Great Britain.

OTHER REFERENCES Guthrie, J. D.; Drake, G. 'L., Jr., and Reeves, Wilson: Application of the THPC Flame-Retardant Process to Cotton Fabrics, Procedings of the American Assoc. of Textile Chemists and Colorists, May 9, 1955, pp. 25.

JOSEPH B. SPENCER, Primary Examiner. RICHARD D. NEVIUS, Examiner.

Claims (1)

1. A PROCESS FOR PREPARING A FLAME-RETARDANT CELLALOSIC MATERIAL WHICH COMPRISES IMPREGNATING THE CELLULOSIC MATERIAL TO BE TREATED WITH AN AQUEOUS DISPERSION OF A HYDROXYMETHYLPHOSPHONIUM CHLORIDE COMPOUND, A WATER-SOLUBLE CYCLIC NTIROGEN-CONTAINING COMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIAZINE AND DIMETHYLOL CYCLIC ALKYLENE UREAS, A WATER-SOLUBLE TERTIARY LOWER ALKYL AMINE, A COMPOUND SELECTGED FROM THE GROUP CONSISTING OF THIOUREA AND UREA, A POLYVINYL CHLORIDE RESIN HAVING A SOFTENING POINT BETWEEN ABOUT 170 AND ABOUT 200*C., AND ANTIMONY OXIDE, AND DRYING AND CURING THE CELLULOSIC MATERIAL.