US2462803A - Fireproofing compositions - Google Patents

Description

Patented Feb. 22, 1949 2.462.803 i- FIREPBOOFING COMPOSITIONS Kenneth S. Campbell and Jack E. Sands, New

leans,

La., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application March 23, 1945,

Serial No. 584,484

9 Claims. (01. 260-'28) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.

This invention relates to flameproofing and is I l more particularly concerned with the flameproofing of organic combustible materials such as those having a cellulose or protein base of either natural plant fibers or artificial fibers. Specific examples of such materials are textiles, such as cotton, silk, rayon, wool, mohair, nylon; braided materials such as ropes and cords; felted materials such as leather, either artificial or natural, paper, and so forth.

This invention embraces new compositions of matter which are applied to the material to be treated for the purpose of flameproofing it, said compositions having a fire-retarding action which remains substantially undiminished after a large number of commercial laundering treatments. The compositions are also effective when applied to cellulosic fabric in a quantity insuflicient to change the physical properties of the fabric to the degree of rendering it unsuitable for clothing purposes. A fabric suitable for clothing purposes would be one which, after flameproofing treatment, has retained the major portion, at least 60%, of its original air-permeability, has lost practically none of its original flexibility, and has not acquired any undesirable properties such as stickiness, or objectionable softening or stiffening on exposure to extremes of heat and cold.

In the prior art, use is made of compositions of certain metallic oxides and chlorine-containing substances to produce flame-retarding finishes. Vinyl chloride resin has been applied to cloth flameproofed by the tin oxide method, the purpose of the vinyl chloride resin being, in part, to suppress the afterglow which is characteristic of the tin oxide treatment. Other treatments involve the use of heavier oxides in conjunction with the chlorinated compounds.

The use of the treatment of the prior art requires the addition to the fabric of such an amount of foreign material that the original weight of the fabric is increased by from 35% to 80%, or more. At the same time, the air-permeability, and consequently the usefulness of the fabric, as clothing material, is reduced to almost nothing. By the use of our invention, the same degree of fire resistance can be obtained without increasing the fabric weight more than about the exact percentage depending on the initial I weight and weave of the fabric. Air-permeability is decreased by our treatment only to a moderate degree resulting in a fabric which is substantially as comfortable to the wearer as the original untreated cloth.

In the prior art, a considerable proportion of the materials added, in addition to the oxide and chlorinated substances, consists of such substances as calcium carbonate and colored pigments which are necessary to prevent excessive deterioration of the cellulose subtrate due to both the gradual hydrolysis or decomposition of the chlorine-containing si'ibstance, forming hydrochloric acid, and the catalytic effect of the ultraviolet in sunlight in the presence of both the metallic oxide and the chlorinated substance. In our invention, however, both of these causes of degradation are neutralized by the presence of a water-soluble urea-formaldehyde condensation product which acts in a buffering capacity and also as a binding agent for the oxide pigment. For example, samples of bleached cotton duck which had been fiameproofed by our process, were completely exposed to the weather for six months. At the end of this time it showed no loss in tensile strength. This same duck, untreated, lost approximately of its strength in the same period of time.

' In the prior art, colored pigments are added for protection against the efiect of light. Our invention, however, makes possible the production of a permanently flameproofed fabric resistant to deterioration by exposure, without the addition of any pigments.

In the prior art, the preferred method of application of the composition is in the form of a volatile, inflammable, solvent solution. Such a solution produces a fire hazard. In our invention, the preferred use of a non-inflammable emulsion has distinct advantages over the solution of the prior art. For example, the use of an emulsion reduces the amount of organic solvent necessary, thus lowering the cost, and at the same time eliminates the fire hazard; also an emulsion is the practical means by which water-soluble urea-formaldehyde condensation product may be combined with the solvent soluble ingredients to form a single homogeneous composition.

In general, our invention comprises the impregnation of organic combustible materials, particularly textile and cellulosic materials with an emulsion containing a metallic oxide selected from the group consisting of antimony oxide, tinoxide and arsenic oxide, chlorinated .paraflln depend in large part on the looseness or tightness of the weave, and initial weight and density of the cloth. For example, light weight material of a very open weave may require no parafin wax of the 42%-4E chlorine variety whatever, while a heavy duck, in order to retain its flexibility after treatment, may require about equal parts. of 42%-45% and 70% chlorine content paraflln wax. Some loosely woven fabrics may profit from the slight stiffening and binding efl'ect resulting from the use of a high percentage of a highly chlorinated type of paramn wax. In some cases, it may prove desirable to use a proportion of 70% chlorine content parafiln wax which produces considerable'stiflness in the dried fabric, and then break down the stiffness by mechanical means, as for example, on a buttonbreaker.

The following examples are illustrative of our invention:

Example I Bleached cotton fiat duck, weighing approximately 7 ounces per square yard, is impregnated by padding, with the following oil-in-water type emulsion: I

' Per cent by weight In the preparation of this emulsion the chlorinated paiaflin wax and the stearic acid are dissolved in the mineral spirits (boiling range 350- 375" F.) and this solution added gradually, with stirring, to an aqueous solution containing the urea-formaldehyde condensation product and the triethanolamine. The antimony oxide is then dispersed in the formed emulsion.

The cloth is then impregnated in the above emulsion in such a manner as to cause it to increase its weight, when dried and finished, by approximately 30%. This control of weight increase of the cloth, as a result of impregnation, may be accomplished by' ordinary suitable means such as pressure-rollers, doctor blades, and so forth. The cloth is then dried, after impregnation, by the most convenient means available and then subjected to a few minutes exposure to a temperature in the range of about 140 to 150 C., the time of exposure being shorter, the higher the temperature, the purpose being the complete polymerization of the urea-formaldhyde condensation product. The cloth is then washed in a hot dilute soap solution, preferably at a boil, rinsed. and dried, preferably on a frame. The dried cloth may then be finished by some type of mechanical breaking-down treatment. if desired.

Fabric treated as outlined has been found to satisfy the fire test of Federal Specification CCC-D-746 after 12 successive wash tests carried out as'specified in the ofliciai Wash test No. 3 of the American Association of Textile Chemists and Colorists. Also, after sixmonths total exposure, this sample was found to have suilered no loss in-tensile strength.

. Eazample II" Cotton herringbone twill fabric, dyed O. D. #7,

weighing 8.5 ounces per square yard, is impregnated by padding, with the following water-in-oil type emulsion:

' Per cent by weight Chlorinated paraflln wax Urea-formaldehyde condensation product 9.00 Antimony oxide (about 325 mesh) 9.90

In the preparation of this emulsion, the first three listed components are dissolved in the mineral spirits (boiling range 350-375 F), and to this solution is added, with stirring, the aqueous solution of urea-formaldehyde condensation product. The antimony oxide is then dispeised in the thus formed emulsion.

The cloth is impregnated'in the above emulsion in such a manner as to make the final dry The finished cloth resulting from the above treatment has been found to meetthe fire test of Federal Specification CCC-'D-746 after fifteen successive wash tests, and other tests as described in Example I.

Having thus described our invention, we claim:

1. A 'flameproofing composition comprising chlorinated paraflin wax, a water-soluble ureaformaldehyde condensation product, and antimony oxide, emulsified in water with an emulsifying agent.

2. A process of flameproofing an organic combustible material comprising impregnating said material with an aqueous emulsion containing chlorinated paraflin wax, a. water-soluble ureaformaldehyde condensation product, and antimony oxide, drying the impregnated material, and. heating thedried material to polymerize the urea-formaldehyde condensation product.

3. An organic combustible material impregnated with an aqueous emulsion containing chlorinated paraflin wax, a water-soluble urea-formaldehyde condensatlon product, and antimony oxide, dried, and having theurea-formaldehyde 70 percent, by weight, of chlorine, a water-soluble urea-formaldehyde condensation product, antimony oxide, water,'and an emulsifying agent, said chlorinated paraflin wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis of the total weight of the ingredients, in the percentages of about from 16.00 to 20.70 percent, from 9.00 to 9.60 percent, and from 6.40 to 9.90 percent, respectively.

5. A process of fiameproofing an organic combustible material comprising impregnating said material with a flameproofing composition comprising chlorinated parafiin wax containing from 42 to '70 percent, by weight, of chlorine, a watersoluble urea-formaldehyde condensation product, antimony oxide, water, and an emulsifying agent, said chlorinated paraflin wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis of the total weight of the ingredients, in the percentages of about from 16.00 to 20.70 percent, from 9.00 to 9.60 percent, and from 6.40 to 9.90 percent, respectively, drying the impregnated material, and heating the dried material to polymerize the urea-formaldehyde condensation product,

6. An organic combustible material impregnated with a flameprooflng composition comprising chlorinated paraflin wax containing from 42 to 70 percent, by weight, of chlorine, a water-soluble urea-formaldehyde condensation product, antimony oxide, water, and an emulsifying agent, said chlorinated paraflln wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis of the total weight of the ingredients, in the percentages of about from 16.00 to 20.70 percent, from 9.00 to 9.60 percent, and from 6.40 to 9.90 percent, respectively, dried, and having the urea-formaldehyde condensation product polymerized.

7. A flameproofing composition comprising chlorinated paraflln wax containing from 42 to 70 percent, by weight, of chlorine, a water-soluble urea-formaldehyde condensation product, antimony oxide. water, and an emulsifying agent, said chlorinated paraflin wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis of the total weight of the ingredients, in the percentages of about 16.00 pierecfi nt, 9.60 percent, and 6.40 percent, respect v 8. A process of flameproofing an organic combustible material comprising impregnating said material with a fiameproofing composition comprising chlorinated parailin wax containing from 42 to '70 percent, by weight, of chlorine, a watersoluble urea-formaldehyde condensation product, antimony oxide, water, and an emulsifying agent, said chlorinated parafiin wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis of the total weight of the ingredients, in the percentages of about 16.00 percent, 9.60 percent, and 6.40 percent,'respec-. tively, drying the impregnated material, and heating the dried material to polymerize the ureaformaldehyde condensation product.

9. An organic combustible material impregnated with a flameproofing composition comprising chlorinated paraflin wax containing from 42 to '70 percent, by weight, of chlorine, a watersoluble urea-formaldehyde condensation product, antimony oxide, water, and an emulsifying agent, said chlorinated paraflin wax, urea-formaldehyde condensation product, and antimony oxide, being present, on the basis ofthe total weight of the ingredients, in the percentages of about 16.00 percent, 9.60 percent, and 6.40 percent, respectively, dried, and having the urea-formaldehyde condensation product polymerized.

KENNETH S. CAMPBELL. JACK E. SANDS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Bacon Dec. 24, 1946 FOREIGN PATENTS Country Date Switzerland June 1, 1939 OTHER REFERENCES Number Number