US2611694A

US2611694A - Fire resistant sheet material

Info

Publication number: US2611694A
Application number: US757663A
Authority: US
Inventors: Becher Hubert Leopold
Original assignee: HOMASOTE Co Inc
Current assignee: HOMASOTE Co Inc; HOMASOTE COMPANY Inc
Priority date: 1947-06-27
Filing date: 1947-06-27
Publication date: 1952-09-23
Anticipated expiration: 1969-09-23

Description

Patented Sept. 23, 1952 FIRERESISTANT SHEET MATERIAL Hubert LeopoldBccher, Trenton, N. J.,-as'signor to Homasote Company, Incorporated, Fernwood, N. J a'corporation of New Jersey No Drawing. Application J une 27,1947, Serial No. 757,663

.1 Myjinvention relates .to 'felted .fibrous sheet material and to methods .ofjproducing the same 'andrelates particularly ..to-.products having improvedfireresistant properties.

"Fibrous.sheetrmaterial such as wallboard and the like, have been 1 produced. heretofore by the use .of fibrous materials'land binders. However, whenlthe fibrousinaterialcor the binder, or both, are .Oforganic origin the sheet material is relatively-inflammableand does not withstand the firectests ,prescribediinmany building codes. One

.particularly .severe Jfire test is that referred to as the "cribtestf :and described in the Proceedings of the-Americansociety lior Iesting Materials, vol. ll, page-238 (1941). .According to this test pieces of the imaterial to ebe tested are arranged in. spacedrelation. and in successive tiers toforma crib or chimney-like arrangement and a Meeker burner is placed beneath the assembly .for a-period of threeminutes. On removal of if the burner the materialashould cease to burn or glow withina prescribed time, generally one minute or-less. 1

Numerous eiiorts have been made to render fibrous-sheet materials fireresistant'by treating or impregnating the sheet withfire retarding agents such as 1 aluminum\ sulfate, borax, ammonium phosphateor thelike. However, in order for such agentstobe applied effectively and economically to sheet material by impregnation or otherwise they must necessarily be soluble in water and they therefore tend to leach out of the finished product if itflis exposed to the weather or to'excess moisture. Moreover, such agents fre- Furthermore, such sheets are not generally adaptedjor use in'the interior of buildings and cannot be sanded or polished topresent an attractive finish and do not lend themselves to decoration by the use of paint, wallpaper or the like.

In accordance with'my invention'a new type of fire resistant sheet material is produced which is relatively light in weight; as compared with 'cement-"asbestosor gypsum sheets and preferably has 'a specific gravity of less than 1.0 and i 6 Claims. (Cl. 92-3) generally about 0.6 to 0.7. These products contain fibrous materialwhich maybe wholly or in large part composed of vegetable fibers and are further characterized by improved impact and tensile strength which permits easy nailing of the material in place, and by their ability to be finished, sanded or machined to produce an attractive finish and one capable of receiving and holding paint, wallpaper and other decorative materials.

These advantages'are obtained by the use of a noveltype of fire resistant and fire suppressing binder for'the fibrous material. A 'hereinafter described the principal active constituent of the binder is an amine type resin. In most'instances the amine type resin is iisedin combination with a chlorinated resin and His further found that by using a metal hydrate in combination with the resin, fire resistant propertie of the finished product arematerially increased. Moreover, the preferred method of producing fire resistant sheet material hereafter described serves to insure substantially uniform distribution of the fire resistant agent throughout the product's'o that even though'the surface of the sheet is'removed by sanding or finishing operations the product will retain its fire resistant qualities.

One of the objects of my invention is to produce a novel'type .of fireresistant fibrous sheet material.

Another object of my invention is to produce a fire resistant felted fibroussheet containing a binder having an amine type" resin as its principal active constituent.

A further object of my invention is to provide fire resistant sheet material wherein the fire resisting agent is largely resinous in character and distributed substantially uniformly throughout the product.

Another object of my-invention is to provide a fire resistant'sheet having: a specific gravityless than 1.0.

Another object .of my invention is s to rovide novel methods for producinglfire resistant'fibrous products.

These and other objects and features of my invention willappear from the-following description thereof in" which typicalj products and methods are described for the purpose of indicating the nature of. my inventiombutwithout intending to limit the scope of the invention thereby.

In producing products-in accordance with my invention any suitabletype of fibrous material may be employed and when producing-a light Weight sheet part or all of the fibrous materia used is generally vegetable fiber, such as news fiber. However, cotton fibers, cotton linters, wool and wood or rag fibers as well as asbestos or mineral fibers may be employed. The fiber employed in the product is generally equal in weight to from about 40 to 60% by weight of the total composition, but these proportionsmay be varied considerably depending upon the type and weight of the sheet material or product desired.

The principal active constituent of the binder employed in accordance with my invention i an amine type resin which preferably is employed in combination with a chlorinated resin and a metal hydrate such as aluminum hydrate. Among the amine resins which may be used are urea, dimethylolurea, monomethanolurea, urea-formaldehyde combinations, melamine, guanidine and the like. The urea resin may be prepared from 1 dimethylolurea and urea in equal molecular proportions. In the alternative the urea resin may consist of molar equivalents of urea and formaldehyde. The amine type resin is preferably introduced into the product in the form of resin forming constituents whereby the resin is actually produced by polymerization of the constituents during the drying of the sheet fibrous composition.

The amount of the binder present in the finished product generally equals from about 40 to 60% by weight of the finished product. At least one-third or more of the binder consists of amine in carrying out the crib test referred to above.

In addition to the amine resin the binder preferably contains hydrated alumina and chlorinated resin. The latter constituents materially increase the eifectiveness of the binder as a fire retarding agent and when such a chlorinated resin is used the amount of the amine type resin employed may generally be reduced. 'I'he hydrated alumina appears to catalyze the decomposition reaction of the amine resin on heating and serves to insure the formation of fire dampening fumes or fire suppressing agents. The acid effect of the chlorinated resin in the product appears to be overcome by the influence of or possibly by combination with, the amine type resin used and it seems probable that ammonium chloride fumes are developed and serve as a fire suppressing agent on decomposition of the amine resin and the chlorinated resin in combination. However, I do not wish my invention to be limited'by any particular theory of operation.

The chlorinated resins which may be used may be chlorinated paraifins of varying chlorine content. Chlorinated diphenyl, polyvinyl chloride, chlorinated rubber and the like also may be used, although I prefer to employ chlorinated paraffin having a relatively high chlorine content, say 70% chlorine. The amount of chlorinated resin employed in the composition may be'varied considerably, but in view of the cost of such resins it is generally preferable to use as little of this resin as required to insure the desired fire resistant properties of the finished product.

4 Ordinarily, this resin amounts to'from about 4 to 12% by weight of the product.

The metal hydrate used is preferably aluminum hydrate and is used in varying amounts equal to from about 12 to by weight of th finished product. r v

A typical; product embodying my invention has the following composition: 7

When produced as hereinafter described, the product is in the form of a' felted fibrous sheet which ceases to burn or glow within about seconds after removal of the burner in carrying out the crib test. The product has a specific gravity between 0.6 and 0.7 and it may be sanded o rtooled to present a very attractive finish. Its tensile strength and modulus of rupture are high and the sheet possesses excellent nail holding properties and an impact resistance exceeding that of cement-asbestos sheets of like thickness.

In producing products in accordance with my invention,'various alternative methods maybe employed. Thus, for example, chlorinated paraffin and aluminum hydrate may be added to a fibrous pulp and the resulting mixture may be sheeted and dried after which the dried sheet may beimpregnated with the amine type resin forming constituents. Subsequent-drying of the sheet serves to cause the resin forming constituents to polymerize producing a fibrous sheet which is suificiently fire resistant to withstand the crib test referred to above.

In the preferred form of producing sheets in accordance with my invention the chlorinated resin and metal hydrate are mixed with the fibrous pulp. The material is then wet pressed until it contains not over about of water. The material is then redispersed in a solution containing the amine resin forming constituents and is thereafter sheeted, pressed and dried. In this way, the fire resisting binder is distributed substantially uniformly througout the sheet and a strong fire resistant product is produced.

In order to illustrate typical procedure in carrying out these methods, the following examples are cited:

Example 1 72 pounds of paper suchas news print are mixed with 3600 pounds of water in a pulper and an emulsionv containing9 pounds of chlorinated parafiin chlorine) are added together with The wet pulp from the pressing operation is passed to av mixer where it is disintegrated and redispersed in 2895 lbs. of a solution containing the resin forming chemicals so as to produce a batch of 3000 lbs. of mix containing ti /2% of solids. The solution is produced by adding 500 lbs. of dimethylolurea and 450 lbs. of urea to 1945 lbs. of water. The mixture is agitated thoroughly and passed to sheet forming and pressing equipment where the product is subjected to a pressure of 50 lbs. per square inch. The product weighs 288 lbs. and contains approximately 50% by weight of water, whereas approximately 2700 lbs. of the liquid pressed out of the sheet is returned for use in the treatment of an additional batch of material. The pressed sheet is then passed to a drier where it is subjected to temperatures about 212 F. until the dry weight of the finished product is approximately 150 lbs. During the drying operation the resin forming constituents added after redispersion of the material are caused to polymerize forming a urea resin which is distributed with the chlorinated paraffin and hydrated alumina throughout the sheet.

This product when subjected to the crib test described above ceases to flame or glow in less than 30 seconds with a loss in weight of less than 30%. The product has a density of approximately 0.6, a tensile strength of 1000 to 1300 lbs. per square inch, 2. modulus of rupture of 1800 to 1825 lbs .per square inch and a water absorption of from 12 to 20%. The product may be sanded or tooled to present an attractive finished surface and possesses considerably greater resistance to impact than sheets of corresponding thickness formed of cement'asbestos compositions.

Example 2 Instead of redispersing the thickened and dehydrated pulp containing the chlorinated paraffin and hydrated alumina as produced in Example 1, the material may be sheeted and dried and thereafter impregnated with a solution of the amine resin forming constituents. For this purpose 150 lbs. of a solution containing 95 lbs. of water, 29 lbs. of dimethylolurea and 26 lbs. of urea may be applied to the dried and pressed sheet in an impregnator to produce a product having a wet weight of 250 lbs. This sheet may then be passed to a drier where it is subjected to temperatures above 212 F. whereby 107 lbs. of water are evaporated and a finished product weighing 143 lbs. is produced.

This product, like that previously described, withstands the crib test for resistance to combustion and has a specific gravity between 0.6 and 0.7 whereas it may be sanded or finished to present a smooth attractive surface.

It will be apparent from the foregoing description that the composition of products embodying my invention may be varied considerably depending upon the properties and characteristics desired in the finished product. It will also be apparent that various modifications may be made in the method of producing products embodying my invention; In view thereof it should be understood that the particular compositions and methods of procedure described above are intended to be illustrative only and are not intended to limit the scope of my invention.

I claim:

1. A fire-resistant felted fibrous sheet material containing from 40 to 60% by weight of fiber, from. 2,0 to 40% by weight of amine resin, from 4 6 to 12% by weight of a chlorinated resin, and from 12 to 20% by weight of hydrated alumina.

2. A fire-resistant felted fibrous sheet material containing from 40 to 60% by weight of fiber, from 20 to 40% by weight of amine resin, from 4 to 12% by weight of chlorinated resin, and from 12 to 20% by weight of hydrated alumina, said fiber being predominantly organic fiber and the sheet material having a specific gravity not exceeding 1.0.

3. A fire-resistant felted fibrous sheet material containing from 40 to 60% by weight of fiber, from 20 to 40% by weight of urea resin, from 4 to 12% by weight of chlorinated resin, and from l2,to 20% by weight of hydrated alumina.

4. A fire-resistant felted fibrous sheet material containing from 40 to 60% by weight of fiber, from 20 to 40% by weight of urea resin, from 4 to 12% by weight of chlorinated parafiin and from 12 to 20% by weight of hydrated alumina.

5. A fire-resistant felted fibrous sheet material having substantially the following composition:

Percent Fibrous material 48 Amine resin 30 Chlorinated resin 5.5 Hydrated alumina 16 6. A fire-resistant felted fibrous sheet material having substantially the following composition:

Per cent Organic fibers 48 Urea resin 30 Chlorinated paraffin 5.5 Hydrated alumina 16 HUBERT LEOP'OLD BECHER.

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

UNITED STATES PATENTS Number Name Date 1 147,833 Fell Feb. 24, 1874 1,907,711 Becher May 9, 1933 2,030,653 Quinn Feb. 11, 1936 2,375,245 Pretzel May 8, 1945 2,410,078 Kellgren Oct. 29, 1946 2,413,163 Bacon Dec. 24, 1946 2,416,447 Laughlin Feb. 25, 1947 2,427,997 White Sept. 23, 1947 2,439,396 Leatherman Apr. 13, 1948 2,462,803 Campbell et al Feb. 22, 1949 FOREIGN PATENTS Number Country Date 821,840 France Dec. 14, 1937 OTHER REFERENCES Hackhs Chemical Dictionary, 3d ed. (1944), pages 615, 733, 734.

Flameproofing Textile Fabrics by Little, published by Reinhold Publishing Corp, New .York, pages 22 2 1 .1 47).

Claims

1. A FIRE-RESISTANT FELTED FIBROUS SHEET MATERIAL CONTAINING FROM 40 TO 60% BY WEIGHT OF FIBER, FROM 20 TO 40% BY WEIGHT OF AMINE RESIN, FROM 4 TO 12% BY WEIGHT OF A CHLORINATED RESIN, AND FROM 12 TO 20% BY WEIGHT OF HYDRATED ALUMINA.