US 2553781 A
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FLAME RESISTANT CELLULOSE FIBROUS MATERIALS AND METHOD OF MAKING SAME Ralph R. Oliver, Lockport, N. Y., assignor to Lockport Cotton Batting 00., Lockport, N. Y.
No Drawing. Application April 14, 1950, Serial No. 156,050
2 Claims. (Cl. 117137) 1 2 This invention relates to improvements in The reason for using surface active agents is fibrous or cellulosic materials of vegetable origin, to induce and increase the penetration of the and to methods of making the same flame or solution of the chemical or chemicals used into flash resistant. the fibers and to wet the surface of the fibers, to
This is a continuation-in-part of my pending 5 produce the desired effect, after drying the application No. 735,022, filed March 15, 1947, fibrous material, of rendering the material flash, k
which in turn was a continuation in part of my and flame resistant. Raw fibers of vegetable copending application Serial No. 434,917, filed origin are usually coated or impregnated with March 16, 1942, and now abandoned. oily or waxy substances which prevent the pene- Heretofore in treating organic vegetable fibers tration of water into the fibers and which prefor this purpose, for example, according to my vent the adhesion of water on the fibers, unless I Patent No. 2,185,695 of January 2, 1940, the cotthe fibers are first subjected to a kier boiling or ton or other fibers have been kier-boiled with saponifying operation in which the oily and waxcaustic soda and then bleached, washed and at like coating materials of the fibers are dissolved least partly dried. The vegetable fibers were or removed from the fibers. I have found, howthen put through a washer containing a solution ever, that by use of anionic or non-ionic surof borax and boric acid. Because the vegetable face active agents, the water in which the borax fibers are absorbent after this boiling and bleachand boric acid are dissolved will readily peneing operation, the borax and boric acid are readtrate the fibers and will adhere to the surfaces ily absorbed thereby. The excess solution was thereof. then removed and the fibers dried. The borax and boric acid are present in the One of the objects of this invention is to probath or solution in the desired quantities to devide raw and unbleached cellplo sicfiber s of vegeposit sufficient of these materials on the fibers table origin which are flame and flash resistant. to produce the desired flame resistant properties Another object is to provide an improved and 26 and to produce a solution having a pH between simplified method of rendering organic vegetable '7 and 8. The pH should not be below '7, since fibers fire-resistant and in which method the a breakdown or deterioration of the fibers resteps of kier boiling and rinsing the fibrous masults if the solution is on the acid side.
' terial may be dispensed with. Another object I have found that in the carrying out of this of this invention is to treat raw fibers of vegetable 30 process a careful control of the temperature of origin in a single step process to make the same the solution containing the borax, boric acid and flash and fire-resistant without interfering with surface active agent should be maintained so the free flexibility of the fibres, so that the fibers that the best results are obtained. For this reacan be Worked on machines without substantial son, the temperature of the bath or solution is loss due to breakage of the fibers, which process preferably approximately from 130 to 212 F., will be relatively simple, inexpensive, efiicient 130 to 140 F. being the best average operating and safe. Other objects and advantages of this temperature. If the temperature of the bath is invention will appear from the following descripmaterially below 130 F., the optimum results are tion and claims. not obtained for the reason that the solution In accordance with my improved process, the 40 does not thoroughly penetrate into the fibers so loose, unspun and unwoven raw vegetable fibers that insufficient borax and boric acid are deare treated in a bath containing a flame and posited within the fibers by capillary action and flash resistant agent, such as borax and boric absorption. Furthermore, borax and boric acid acid, and a surface active agent. Any suitable are more readily soluble in warm water than in or desired anionic or non-ionic surface active cold water, and it is desirable to have the bath 5' or wetting agent may be employed, many agents as concentrated as possible to deposit the maxiof this type being now available on the market. mum quantity of borax and boric acid on and For example, any of the following materials may in the fibers, and if the solution drops below be employed as surface active agents: F., some of these ingredients crystallize out of Alkyl aryl sulphonate 50 the solution. If the temperature is materially Dioctyl ester of sodium sulfosuccinnic acid Over the fibers tend to become somewhat p i d ethylene Oxide Condensate more brittle due to breakdown of the cellulosic s mm fatty alcohoy material. This is particularly noticeable dur- Alkali soap of naphthenic acid ing the mechanical treatment of the cotton, such Quaternary ammonium salts .55 as carding and. garnetting.
In the use of this process on vegetable fibers, such for example as cotton, the material from the bales is first fluffed up in any usual or suitable manner such as heretofore commonly employed, and the fibrous material is then discharged into a tank containing the bath and is kept submerged in the bath while passing from one end of the tank to the other. At the other end of the tank the vegetable fibers are withdrawn from the bath and excess solution is pressed out of the material. This may, for example, be accomplished by passing the material between rollers which squeeze out excess solution from the fibrous material, so that the amount of solution left in and on the fibrous material is about from 30% to 50% of the weight of the fibrous material. It is desirable to leave a certain amount of this solution on the outer surfaces of the fibers so that when the fibers are dried, the required amount of borax and boric acid is left on the surfaces of the fibers as Well as in the interior thereof. The cotton or other fibrous material may then be dried in any suitable or desired manner, for example in a raw stock drier, such as commonly used in the treatment of cotton. This drier removes the water from the fibrous material and leaves the borax and boric acid in and on the fibers, and thus makes the same resistant to fiame and fire, without, however, changing the flexibility of the fibers and without making them brittle. The drying is preferably carried on until about 8% to 10% of moisture remains in the material.
As an example of the treatment of cotton and other vegetable fibers in accordance with this invention to render them flame resistant without subjecting the fibers to a kier boiling process, the flame proofing ingredients are dissolved in water in the proportion of one to two pounds per gallon of water, these ingredients including approximately two parts by weight of borax to one part of boric acid. The resulting solution will then have a pH of approximately from 7 to 8. To this solution is added approximately from onetenth to one-half of one percent by weight of the solution of a suitable surface active agent, which percentage may be varied according to mill conditions and according to variables that occur in all raw water. The final solution is raised to a temperature between 130 F. and 212 F., about 130 F. to 140 F. being preferred, and the raw cotton or other vegetable fibers are then immersed in this solution until the fibrous material is completely wetted out. The surface active agent greatly increases the penetrating action of the solution so that the same fills the canals of the fibers and penetrates the fiber walls or cells. In such a bath, the raw, previously untreated fibers very rapidly sink and become fully impregnated and saturated with the solution. Generally after the cellulosic material has been immersed in the solution for about two minutes, the solution will have fully penetrated the fibers. The fibrous material is then withdrawn from the solution and pressed to remove excess solution, leaving from 30% to 50% of solution by weight of the fibrous material thereon, and dried as already described.
After the fibers have been dried, the weight of the same is increased about 12% to 15 due to the absorption and incrustation of the flames proofing substances in and on the fibers, and the fibers are not brittle and may be worked in any of the usual machines, such as carding and garnetting machines, in which the fibers are formed into resilient batts suitable for house and building insulation, or for other purposes. It has also been found that fibers treated in accordance with my process are stronger and better adapted for heat insulation than fibers which have been kier boiled. Heretofore in processes for making cotton fire resistant, a certain percentage of the fibers has been lost during the flame-proofing of the same because preliminary kier boiling made these fibers brittle, but with my improved treatment, in which no kier boiling or saponification is necessary or desirable, the loss of fibers is substantially avoided. The term raw as herein applied to vegetable fibers includes not only the fibers as they come from the plants, but also gray stock, which has not been chemically treated or kier boiled.
It will be understood that various changes in the details, materials and conditions, which have been herein above described in order to explain the nature of the invention may be made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims.
I claim as my invention:
1. A method of treating loose, raw, cellulosic fibers to render the same flame and fire resistant without substantially changing the flexibility of the fibers and wherein the fireproofing composition is deposited on and in the fibers, which method comprises subjecting the raw fibers to an aqueous solution maintained at a temperature between F. and F. and at a pH of approximately between 7 and 8, said solution containing borax, boric acid and a compatible sur face active agent, the borax being present in the proportion of the approximately 1 pound per gallon of water, the boric acid being present in an amount of approximately A.; pounds per gallon of water and the surface active agent being present in an amount of approximately to percent by weight of the solution, heating the solution, and maintaining it at a temperature within the range indicated, leaving the fibrous material in said solution for at least two minutes, removing the material from said solution, removing solution from said material until the amount of solution adhering to the material is equal to approximately 30% to 50% by weight of the material and then drying the material, whereby the amount of flame and fireproofing composition deposited on and in the fibers is from about 10% to 15% by weight of the fibrous material.
Z A flame and flash resistant, loose, raw cellulosic material having substantially the properties of the product resulting from treatment by the process of claim 1.
RALPH R. OLIVER.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,178,625 Clayton Nov. 7, 1939 2,185,695 Oliver Jan. 2. 1940