United States Patent: 3619113

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United States Patent	3,619,113
Stockel , et al.	November 9, 1971

FLAME-RETARDANT FINISH FOR CELLULOSIC TEXTILE MATERIALS

Abstract

A flame-retardant finish for cellulosic textile materials, the method of applying it and the textile materials treated with the flame retardant. More particularly, the flame-retardant finish comprises an aqueous solution of tris(hydroxymethyl)phosphine (THP) or tris(alkoxymethyl)phosphine (formula I), a methylolated nitrogenous cellulose reactant and, optionally, urea. P(ch.sub.2 or).sub.3

Inventors:	Stockel; Richard Frederick (Bridgewater Township, Somerset County, NJ), O'Brien; Samuel James (Dunellen, NJ), Weyker; Robert George (North Plainfield, NJ)
Assignee:	American Cyanamid Company (Stamford, CT)
Appl. No.:	04/861,481
Filed:	September 26, 1969

Current U.S. Class: 8/183 ; 252/608; 427/393.3; 442/143; 528/244; 8/195

Current International Class: D06M 15/431 (20060101); D06M 15/37 (20060101); D06m 013/14 (); D06m 013/28 (); C09k 003/28 ()

Field of Search: 252/8.1 117/136,137,143,144,145 161/191 8/116P,116.2,116.3

References Cited [Referenced By]

U.S. Patent Documents


2809941	October 1957	Reeves et al.
2810701	October 1957	Reeves et al.
2937207	May 1960	Reuter et al.
3257460	June 1966	Gordon et al.
3452098	June 1969	Vullo

Other References

Reeves et al. "Flame Retardants for Cotton Using APO-and APS-THPC Resins," Textile Research Journal, Vol 27, No. 3, Mar., 1957, pp. 260-266. "Flame Retardant Gets Plant-Scale Trial" Chemical and Engineering News, Sept. 9, 1968, pp. 42 and 43..

Primary Examiner: Goolkasian; John T.
Assistant Examiner: Fritsch; D. J.

Claims

We claim:

1. A flame-retardant finish for cellulosic textile materials comprising phosphine of the formula

P(CH.sub.2 OR).sub.3

wherein R is hydrogen or lower alkyl, and methylolated nitrogenous cellulose reactant.

2. A finish as in claim 1 where the methylolated nitrogenous cellulose reactant is a methylolated melamine.

3. A process for imparting a flame-retardant finish, as in claim 1, to cellulosic textile materials comprising applying tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine of the formula

P(CH.sub.2 OR).sub.3

where R is hydrogen or lower alkyl, and methylolated nitrogenous cellulose reactant.

4. A cellulosic textile material treated by the process of claim 3.

5. A finish as in claim 1 comprising in addition, formaldehyde.

6. A finish as in claim 5 wherein said ingredients are at least partially reacted together.

7. The finish of claim 1 where the phosphine is tris(hydroxymethyl)phosphine.

8. The finish of claim 1 where the nitrogenous reactant is melamine.

9. The finish of claim 1 containing in addition, urea.

Description

This invention relates to a flame-retardant finish for cellulosic textile materials, to the method of applying it and to the textile materials treated with the flame retardant. More particularly, the flame-retardant finish comprises an aqueous solution of tris(hydroxymethyl)phosphine (THP) or tris(alkoxymethyl)phosphine (formula I), a methylolated nitrogenous cellulose reactant and, optionally urea.

P(CH.sub.2 OR).sub.3

I

In formula I, R is hydrogen or lower alkyl.

Certain derivatives of THP, such as tetrakis(hydroxymethyl)phosphonium chloride (THPC) of formula II and tris(hydroxymethyl)phosphine oxide (THPO) of formula III, are components of flame-retardant systems. U.S. Pat. No. 2,809,941 and other references disclose the use of polymeric condensation products of THPC and/or THPO with methylolated nitrogenous compounds as flame retardants for cellulosic textile materials. Cellulosic textile materials treated with flame-retardant amounts of THPC and/or THPO and the coreactant nitrogenous compound have certain deficiencies, including tensile strength loss and undesirable hand characteristics such as stiffening.

C1P(CH.sub.2 OH).sub.4

II

OP(CH.sub.2 OH).sub.3

III

It is therefore an object of this invention to provide a flame-retardant composition for cellulosic textile materials using a phosphine compound.

A further object is to provide such a finish whereby a good hand is retained by the treated textile material.

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

It has now been discovered that textile finishes containing tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine and a methylolated nitrogenous cellulose reactant impart durable flame-retardant properties to cellulosic textile materials without significant sacrifice of tensile strength or softness of hand. The cellulosic textile materials thus treated exhibit a high degree of flame retardancy which is durable to repeated laundering.

Tris(hydroxymethyl)phosphine (THP) is an old compound, its manufacture having been disclosed at least as early as 1960 (U.S.S.R. Pat. No. 138,617). (Its preparation is also the subject of American Cyanamid, U.S. Pat. No. 3,243,450, with utility disclosed as a gasoline additive.) Tris(alkoxymethyl)phosphine can be prepared by reacting THP with a lower alcohol in the presence of a strong acid such as hydrochloric acid.

Examples of useful methylolated nitrogenous cellulose reactants include aminoplast resin precursors such as methylol melamine, methylol ureas, methylol carbamates, etc., and their alkylated derivatives. The methylol compounds contain two or more methylol groups per molecule of nitrogenous compound. The preferred reactants are methylol melamines and their alkylated derivatives.

Representative melamine compounds include dimethylol melamine, dimethylated trimethylol melamine, hexakis(methoxymethyl) melamine, partially methylolated pentamethylol melamine, etc. Representative urea compounds include dimethylol urea, tetramethylol urea, methylated dimethylol urea, dimethylol ethylene urea, etc. Representative carbamate compounds include dimethylol methyl carbamate, dimethylol ethyl carbamate, dimethylol hydroxyethyl carbamate, etc. Combinations of the above methylolated nitrogenous compounds may also be used.

The components of the fire retardant finish can be applied to the textile material from the same bath or from separate baths by padding, dipping, spraying, etc. For maximum durability it is of advantage to dry the textile at a temperature of about 75.degree. to 115.degree. C., preferably at 100.degree. to 110.degree. C., before the finish is cured at a temperature from about 125.degree. to 175.degree. C., preferably at 140.degree. to 160.degree. C. The time required for curing is between 1 and 5 minutes, depending on the temperature used and the weight of the fabric.

In another procedure, tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine, nitrogenous compound and formaldehyde are applied to the textile material.

In a third procedure, tris(hydroxymethyl)phosphine, nitrogenous compound and formaldehyde are reacted, either partially or completely, in aqueous medium before application to the textile material. Water soluble products are obtained.

The amount of tris(hydroxymethyl)phosphine or tris(alkoxymethyl)phosphine applied to the cellulosic textile material should be between 15 and 50 weight percent, preferably between 20 and 25, based on the weight of the textile material.

The amount of methylolated nitrogenous cellulose reactant, or alkylated derivative, applied to the cellulosic textile material will depend on the nitrogen content of the reactant. Sufficient reactant should be applied to provide, on a weight basis, between 50 and 300 percent of nitrogen, preferably between 100 and 200 percent, based on the phosphorus applied to the textile material. This relative amount of each compound may be determined by a calculation of the weight of nitrogen in the particular nitrogenous compound, calculating the amount of phosphorous according to the weight ratio stated and then the amount of phosphine which will contain that amount of phosphorous.

The addition of urea to the application bath improves the stability of the bath. It also improves the durability of the flame retardancy and reduces strength losses of the treated fabric. The amount of urea added to the bath should be at least 3 percent, preferably between 3 and 6 percent, based on the weight of the textile material.

The cellulosic textile material should contain at least 50 percent cellulosic fibers. By cellulosic fibers is meant such fibers as cotton, regenerated cellulose (rayon), linen, jute, etc. Blends of cellulosic fibers or blends of cellulosic fibers with noncellulosic fibers, both natural and synthetic, such as silk, wool, nylon, polyester, acrylic, etc., may be used.

EXAMPLE I

PREPARATION OF TRIS(HYDROXYMETHYL)PHOSPHINE

An autoclave charged with 48 g. of paraformaldehyde and 104 g. of 44 percent aqueous formaldehyde was heated at 100.degree. C., and phosphine was introduced in sufficient amount (about 34 g.) to maintain a pressure of 400 p.s.i. The product is a 68 percent aqueous solution of tris(hydroxymethyl)phosphine.

EXAMPLE II

REACTION PRODUCT OF TRIS(HYDROXYMETHYL)PHOSPHINE, MELAMINE AND FORMALDEHYDE

A mixture of 25 g. of tris(hydroxymethyl)phosphine, 10 g. of malamine, 7.5 g. of formaldehyde and 17.5 g. of water was stirred at 65.degree. C. for 1 hour. A clear solution was obtained.

EXAMPLE III

METHYLATED REACTION PRODUCT OF TRIS(HYDROXYMETHYL)PHOSPHINE, MELAMINE AND FORMALDEHYDE

A mixture of 50 g. of tris(hydroxymethyl)phosphine, 50 g. of melamine 166 g. of 37 percent aqueous formaldehyde and 100 g. of water was stirred at 50.degree. C. and pH of 7.5 (pH adjusted with sodium hydroxide) for about 3 hours. Methanol (150 ml.) and sufficient 30 percent hydrochloric acid to provide a pH of 6.0-6.5 were added. The resulting solution was concentrated by evaporation of 50 percent solids content.

EXAMPLE IV

REACTION PRODUCT OF TRIS(HYDROXYMETHYL)PHOSPHINE, MELAMINE AND FORMALDEHYDE

A mixture of 33 g. of 60 percent tris(hydroxymethyl)phosphine, 10 g. of melamine 10 g. of 44 percent aqueous formaldehyde and 5 g. of water was heated at 55.degree. C. and pH 8.0 for 2 hours. The product was a clear solution containing 55 percent solids.

EXAMPLE V

Three aqueous pad baths were prepared of the following percentage composition:

A B C __________________________________________________________________________ Tris(hydroxymethyl)phosphine 20 20 20 Urea 5 10 15 Methylol Melamine* 6 6 6 Water 69 64 59

The pad baths were applied to 10 .times. 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The padded fabrics were dried at 107.degree. C. for 2 min. and then heated at 159.degree. C. for 5 min. The fabrics were thoroughly washed with water and dried at 107.degree. C.

The durability of the flame-retardant finishes to laundering was determined by repeatedly washing the fabrics in an automatic washing machine, using water at 140.degree. C. and a commercial detergent and drying in a tumble dryer. 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 testing 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 results are shown in table 1. Fabrics A, B and C correspond to pad baths A, B and --------------------------------------------------------------------------- C. --------------------------------------------------------------------------- TABLE 1

A B C __________________________________________________________________________ No. washes before failure 15 >17 7 __________________________________________________________________________

When the methylol melamine was omitted, the flame test failed after one wash.

EXAMPLE VI

An aqueous pad bath containing 50 percent of the product of example II and 5 percent of urea was applied to 80 .times. 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The treated fabric was dried at 107.degree. C. and then heated at 150.degree. C. for 3 min. The fabric was washed in warm water and dried.

The durability of the flame retardant finish to laundering was determined by the procedure of example V to be at least 50 washes.

EXAMPLE VII

An aqueous pad bath containing 20 percent of the product of example III, 10 percent of urea, and 6 percent of an aminoplast resin comprising 75 percent of methylated hexamethylol melamine and 25 percent methylol urea was applied to 80 .times. 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The treated fabric was dried at 107.degree. C. for 2 min. and then heated at 159.degree. C. for 4 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be about 8 washes.

EXAMPLE VIII

An aqueous pad bath containing 50 percent of the product of example IV and 5 percent of urea was applied to 80 .times. 80 cotton percale by a standard padding procedure obtaining a 100 percent wet pickup. The treated fabric was dried at 107.degree. C. for 8 minutes and then heated at 149.degree. C. for 3 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be at least 40 washes.

EXAMPLE IX

A mixture of 62 g. of tris(hydroxymethyl)phosphine, 93 g. of a 60/40 mixture of 1,3-dimethylol-5-hydroxyethyltetrahydrotriazone and polymethylolurea (about 3.2 methylol groups per mole of urea), and 122 g. of water was heated at pH 9.5 and 60.degree. C. for 5 hours. A clear solution was obtained.

EXAMPLE X

An aqueous pad bath containing 56 percent of the product of example IX, 8.5 percent of partially methylated trimethylol melamine and 6.4 percent of 85 percent phosphoric acid* was applied to 80 .times. 80 cotton percale by a standard padding procedure obtaining an 80 percent wet pickup. The treated fabric was dried at 107.degree. C. for 4 minutes and then heated at 150.degree. C. for 4 minutes.

The durability of the flame-retardant finish to laundering was determined by the procedure of example V to be at least 45 washes.

* * * * *

Current U.S. Class:	8/183 ; 252/608; 427/393.3; 442/143; 528/244; 8/195
Current International Class:	D06M 15/431 (20060101); D06M 15/37 (20060101); D06m 013/14 (); D06m 013/28 (); C09k 003/28 ()
Field of Search:	252/8.1 117/136,137,143,144,145 161/191 8/116P,116.2,116.3