US2472335A

US2472335A - Method of flameproofing combustible cellulosic material

Info

Publication number: US2472335A
Authority: US
Inventors: Mclean Andrew; Marrian Stanley Frederic
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1945-01-10
Filing date: 1945-11-15
Publication date: 1949-06-07
Anticipated expiration: 1966-06-07
Also published as: FR919288A; BE461753A

Description

Patented June 7, 1949 METHOD OF FLAMEPROOFING COMBUS- TIBLE CELLULOSIC MATERIAL Andrew McLean, West Kilbride, and Stanley Frederic Marrian, Ardrossan, Scotland, assignors to Imperial Chemical Industries Limited, a corporation of Great Britain No Drawing. Application rial No. 628,994. In Great Britain January 10,

November 15, 1945, Se-

6 Claims. (Cl. 117-137) The present invention relates to a new or improved method of flame-proofing combustible cellulosic materials that enables them to be washed or laundered in hot aqueous media'without losing their flame-proof qualities, and to the resulting fiame-proofed cellulosic materials. The invention also relates to a new reagent for use as a flame-proofing component according to the aforesaid new or improved method of flame-proofing combustible cellulosic materials.

Amongst the cellulosic materials to which the invention is especially applicable are textile fabrics, for instance woven or pleated fabrics, threads, yarns, filaments, and fibres, made of cotton, linen, regenerated cellulose, jute, cellulose acetate, and the like.

Various proposals have already been made in connection with the flame-proofing of combustile materials but these proposals for the most part have suilered from such disadvantages as the necessity of having to employ large amounts of reagent to ensure effective flameproofing thereby stiifening the materials to an undesirable extent, the difliculty experienced in fixing the reagent satisfactorily to the combustible materials so that it will resist laundering operations, and the scarcity or difliculty of production of some of the reagents proposed.

A process has already been disclosed which comprises treating with an acidic-flre-retardant as for example phosphoric acid or calcium phytate a cellulosic material impregnated with polyethyleneimine.

An object of the present invention is to provide a method of flame-proofing combustible cellulosic materials, and a new flame-proofing component used in carrying out the method, yielding flame-proof products that retain their flame-proof qualities subsequent to hot water washing and laundering with hot soap solutions in a more satisfactory degree than heretofore.

It has been found that compositions comprising the novel compound pentaerythritol tetraorthophosphate can be readily anchored to cellulosic materials impregnated with a polyethyleneimine to give flame-proof cellulosic materials which retain their flame-proof characteristics subsequent to their treatment with soap and water washing.

According to the present invention therefore the method of flame-proofing combustible cellulosic materials comprises treating the said materials impregnated with .a polyethyleneimine with a solution comprising pentaerythritol tetraorthophosphate.

The flame-proofing component according to the present invention" for flame-proofing combustible cellulosic materials previously subjected to the action of a polyethyleneimine comprises pentaerythritol-tetra-orthophosphate.

Crude pentaerythritol tetra-orthophosphate was prepared from pentaerythritol, ortho-phosphoric acid and phosphorus pentoxide as follows, the quantities employed being based upon the molecular ratio of three parts pentaerythritol, four parts of ortho-phosporic acid and four parts phosphorus pentoxide.

Phosphoric acid (11 gr. of 88%) was added gradually to phosphorus pentoxide (25 gr.) and when the mixture was cool, pentaerythritol (15.3 gr.) was added thereto, the whole being well stirred. The mixture was heated in an oil bath at -130 C. for 20 hours with exclusion of moisture and occasional stirring. The crude pentaerythritol tetra-orthophosphate product thus formed probably contained phosphoric acid and pentaerythritol tri-, diand monoorthophosphate in addition to the pentaerythritol tetra-orthophosphate.

Comparative experiments were carried out to illustrate the differences in behaviour to washing with soapand water of cotton cloth in every case first treated with an aqueous solution of polyethyleneimine in the manner specified and subsequently with aqueous solutions of the crude pentaerythritol tetra-orthophosphate, an aqueous solution of a mixture of the three reactants upon which the heat treatment was omitted, the mixture being immediately dissolved in water, and an aqueous solution diluted as required of a mixture of. phosphoric acid and phosphorus pentoxide only which were heated together before dissolving in water. Solutions of various concentrations were used.

Experiments were also carried out to see how to improve the handle or feel of the combustible cellulosic materials and yet retain the desired fireproof qualities after soap and water washing.

The handle or feel is found to be often improved by cutting down the quantity of polyethyleneimine with which the combustible cellulosic materials is impregnated, as for example by working with polyethyleneimine solutions of strengths lower than 8-12 per cent, but to make certain that in such cases the product remains flame-proof after soap and water washing it is often necessary to treat it subsequent to the pentaerythritol tetra-orthophosphate treatment with an acidified aqueous solution of hexamethoxymethyl melamine or triethoxymethyl melamine followed by baking at about 100 C. The said acidification can be efiected for ex-' ample with paratolueue sulphonic acid.

A piece of cotton cloth (12 sq. ins.) was soaked in 10 ml. or a boiling aqueous solution of polyethyleneimine for one hour, wrung out and baked in a steam oven overnight. The clot-h was then steeped in 15 ml. of an aqueous solution of the crude pentaerythritol tetra-orthophosphate for one hour at room temperature, thoroughly rinsed, and dried. The time given for each operation and the quantities used were arbitrarily fixed.

Testing of fiame-proofness was carried out by holding the cloth in a Bunsen flame for 5-10 4 impregnated with an aqueous 8% to 12% polyethyleneimine solution.

3. A method as claimed in claim 1 wherein the cellulosic materials are subsequently treated with an acidified aqueous solution of a compound from the group consisting of hexamethoxymethyl melamine and triethoxymethyl melamine, followed by baking at about 100 C.

4. A method as claimed in claim 3 wherein the compound selected is hexamethoxymethyl melamine.

5. A method as claimed in claim 3 wherein the compound selected is triethoxymethyl melamine.

' 6. Flame-proofed combustible cellulosic textile seconds. Some charring always took place, but if 15 m i l imp w h p yethylenimine and burning was not propagated with any speed in containing pentaerythritol .tetra-orthophosphate the flame and ceased without afterglow when as the flameprmfing compimentthe cloth was removed from the flame, the cloth ANDREW MCLEAN. was recorded as flame-proof. If either of these STANLEY FREDERIC MARRIAN. conditions was not satisfied the sample was recorded as not flame-proof. REFERENCES CITED The stability of the fl meqn-oofness to wash- The following references are of record in the ing was tested as follows: The test piece was me of this Patent: stirred with 2:0 :11. 1iiv later at 4(fJ-50" C. forh T UNITED STATES PATENTS minutes and rie ame-proo ness was t en tested as above. The same piece was then stirred Number Name Date 1,660,651 Marshall et a1 Feb. 28, 1928 with 200 ml. of 0.25 per cent soap solution at 2,071,353 Morgan Feb, 23, 1937 40-50 C. for 30 minutes, wrung out, rinsed thor- 2,286 726 Gordon June 16 1942 oughly in 3 changes of water and dried. The 30 fiame-proofness was again tested. FOREIGN PATENTS The results obtained are given in .the following Niunber Country Date table: 476,043 Great Britain Apr. 27, 1936 Bar Alta W is Alte s was i g Wa shlgg r Water $5 331;

1: l i i n i fiiifiihiiififilfiifii. i$ 5231 1 Billion. f'ffifffff: ?fff: fiiiififilfi'aor 109g polyethyieneimine, l a control 1 iiquor. d D 10% polyethyleneimine, 10% phosphoric acid.. a 9 polyethyleneiminc, 8% p. t. p ilameproor. 3 polyethylencimme, 8% phosphoric acid. not llameprooi. 4 7 polyethyienei nine, 4 Do. 4 ,polyethyieneimine, 4% hosphoric aci Do, 5,polyothyleneimine, 1 p. t. Do. 59 polyethyieneimine, 10% p t. p. Final treatment with a solution containing 2 grams ilameprooi examethoxymethyl melamme+0.05 grams 1. toluene sulphonic acid in 18 cc. water (ior l2 sq. ins. cloth) followed by baking at 100 C. for 1 hour). %L"Lii'ii:2$ii.3it' ittifiifiiith iii i r iothfgllow ed by baking at 10% ice l hour. p M n cc wawr (or 12 sq' ms.

p. t. p.=pentaerythritol tetra-orthophosphate.

1 Solution of unheated mixture oi pentaerythritol, phosphoric acid and I Solution of heated mixture of phosphoric acid and phosphorus pentoxid phosphorus pontoxide. e.

OTHER REFERENCES Chem. Abstracts. vol. 38, p.

Chem. Abstracts, vol. 32, p.