US1655718A - Examiner - Google Patents

Description

a. commas? i comma 0R Prism Patented Jan. 10, 1928.

UNITED STATES PATENT OFFICE.

HOWARD F. WEISS AND RALPH FORBUSH BY IESNE ASSIGNMENTS, T0

SIGNORS,

NORRIS, OF MADISON, WISCONSIN, AS- C. F. BURGESS LABORATORIES, INC., OF

WALL BOARD.

R0 Drawing.

The present invention relates to wall boards suitable for use on the walls or cellings of a room and having good heat insulating ua-lities. It is made from a mixture of a fil er and a binder which pufi's into a porous rigid coherent mass under the' action of heat and is provided with a facing of other material. It is an object of the present invention to produce a molded product composed for the most part of inorganic material, that product being light in weight, cheap in cost, and having a high porosity, and, consequently, a low thermal conductivity. The wall boards of the present invention may be of the thickness and of the size of ordinary paper wall boards, and have a facing of paper on one or both sides. This sheet material can be put between the studding of a building to serve in place of back plaster. It can also be used in sheets or blocks to form a wall or ceiling over which a layer of plaster or hard finish can be applied. Similarly it may be used as the exposed surface of the wall, and before or after attachment to the studding may be decorated with enamel, paint, calcimine, or the like, applied directly to the mineral sheet, or applied to the paper facing or facings.

As set forth in a copending application, Serial No. 7 520,511, filed June 17, 1924, when an intumescent binder such as a soluble alkali silicate, hide glue or cornstarch is mixed with a filler and subjected to the action of heat, the mass expands or puffs up and ultimately hardcns into a firm strong body filled with air cells or pores. the size and distribution of which we find can to a large extent be. controlled. Unless the expansion or pufling of the materialis restricted as in a closed inold or form. the expansion is likely to proceed so far that the resultant product will be too light and {)rothy to accomplish the ends now desired y us. I

The density and the physical characteris tics of wall boards made from such material by the application of heat in a mold will depend in part on'the relative percentages of binder and filler; in part on the size ofthe moltbwith respect to -theamount of raw Application filed June 17, 1824. Serial No. 720,510.

material put in for heat treatment, and in part on the chemical and physical characteristicsof the filler. By suitable control of these factors, and of the temperature and duration of heat treatment, a wide range may be obtained in the physical characteristics of the product.

Various fillers can be used, such, for exzmple, as crulslhedldololinitle, limestone, blast urnace or ot er s ag, ao in, s ate asbestos eit s or owder arious clays, ag wool, pow ere s1 ica, ochre, tripoli, olcanic ash, pggnice, kieselgu'hr, ashes, or various 1nixtnre s t.hereof.

Instead of using a filler that is entirely, of mineral origin, there may be incorporated in the mixture beforeheattreatment thereof, organic materials, such-a 1r, wood pul fcurkfsawdust, charcoal, .SVOOfl slivers, or shredded barkT"Such organic materials may be used to alter the properties to the degree desired. For certaln purposes the filler may be entirely of organic origin.

By way of illustration we ive below detailed instructions for procee ing in accord- :nce with the method of the present invenion.

An alkali silicate, such as sodium silicate, having a density of about 425 B. is intimately mixed as in a mixer with a filler to form a dough having a consistency about' like that of putty. The amount of filler varies with its character, for example in using dolomite the filler constitutes about of the weight of the wet mix, while in using kieselguhr or sifted coal ashes, the filler constitutes only 20% of the weight of the wet mix. When the board or panel is to have a paper facing on both sides, the dough or m1x thus formed is spread upon a sheet of paper either 'in an even layer oras strips. (an even layer having a depth of to will form a board approximately in thickness) A second sheet of paper. is .placed'on top of the dough so that the product in its green condition consists of} two sheets or strips of paper with a: layer. of doughbetween. The paper we havebeen' using is an ordinary chip board rather heavily sized so that it be water'ra istant and tough, although, of course, other kinds of paper can be used. The green sheet is then slid between two steam heated iron platens spaced a distance equal to the thickness desired for the finished board, say, for instance, The steam platens can be heated with steam at a pressure of about to 100 lbs., but a temperature of more than about 1' 0 C. should not be employed to avoid charrmg of the paper facing. The application of heat of about that temperature causes the dough to pull u and force the upper sheet of paper against t 1e upper platen. During this heating process steam is driven oil from the mixture, particularly along the edges of the board. Some dough also may escape around the ed es of the board without disadvantage. uring this heating and expanding process, and the driving oil of water from the mixture the silicate undergoes a radical physical change, and there may even be a chemical reaction between the silicate and the filler. In about thirty minutes the dough has puffed sulficiently and suiticient moisture has been driven OK so that the board in its pufied and porous condition is stifier than when it was wet or green, although it still is somewhat plastic. The hot board is then sli ped from between the latens and pressed tween two rigid suraces and there allowed to cool so that when it has cooled it is held sufiiciently fiat. It is then in a stiff hardened and porous condition, and can be trimmed with saws and cut to the desired dimensions.

If the board is to be faced with paper on one side only, a greased iron sheet is substituted for one of the paper sheets.

The tenacity with which the composition sticks to the paper sheets is one of the important characteristics of the paper faced board, for there is no tendency for the sheets to blister or strip away from the mineral filler. The paper is very tenaciously held, thereby strengthening the board and adding to its resistance against chipping during shipment, or while nails are being driven through it into the studding. In cross section the inorganic core of the finished board is not unlike in appearance the cross section of a loaf of fine grained bread.

\Ve have found that a soap, such s sodium resinatc, stearate and the like, or material such as oleic acid which will be saponified by the silicate, can be advanta eously added to the batch, for controlling t to size and distribution of the air bubbles or cavities. For instance, with a mixture of sodium silicate and ashes in about equal parts by weight there may be added soap to the extent of less than one-half of one percent by 'weight. This soap addition makes the bubbles smaller, but more numerous, and reduces the apparent density of the finished product. Presumably these holes or cavitics represent spaces where steam was trapped in the mix during the putting procedure.

Using 2.7 parts by weight of sodium silicate of 425 B., 4.0 parts of finely ground dolomite, then mixing to a stiff dough, there may be produced, after heat treatment, a strong product weighing 45.0 lbs. per cu. ft. By increasing the proportion of dolomite a heavier product will result. Thus by adding 6.0 parts of dolomite in the mix indicated, a product weighing 62 lbs. per cu. ft. may be made. It is not advantageous to make a denser product.

We have found the following batch to give excellent results, the percentage given being parts my weight 39% 425 B. sodium silicate solution.

58% powdered dolomite.

29% fine sawdust.

0.1% sodium oleate.

Dolomite, which consists essentially of calcium and magnesium carbonates in varying proportions up to about and 45% respectively, is widely distributed throughout the United States, and is available in large quantities and low cost in the State of Illinois and in neighboring States. See Bulletin 46 of the State of Geological urvey of Illinois entitled Lime stone resources of Illinois).

The wall board made as above described can be sawed and handled much as plaster or gypsum board is handled, and has the advantage thereover that it is lighter in weight and far more porous. Not only is the material of low conductivity for heat and sound, but it has a low water absorption coefficient and if necessary can be waterproofed.

1. A wall-board characterized by the tcnacity between the core and the facing comprising a mixture of an intumescent binder and a filler, puffed by heat to a highly porous coherent b0 and having a facing held in place by the intumesced binder.

2. A wall-board characterized by the tonacity between the core and the facing comprising a mixture of an alkali silicate and a filler, pufied by heat to a highly porous body, and having a facing held in place by the int-umesced binder.

3. A wall-board characterized by the tenacit between the core and the facing welg ling not more than 62% pounds per cu. ft. comprising a mixture of an alkali silicate and a filler, putfed by heat, and having a facing held in place by the intumesced binder.

4. A wall-board characterized by the tenacrty between the core and the facing comprising a mixture of an alkali silicate and a of a rous character,

and having a facing held in place by the intumesced binder.

ller,fip)ufled by heat to a highly porous body i106. eoneosinoas,

, 500mm R Cross Reference EXAMINEF 5. A wall-board characterized by the tehaving a high degree of tenacity between nacity between the core and the facing comthe core and the facing which comprises prising a mixture of an alkali silicate and a mixing an intumescent binder with a filler, heavy mineral filler, and a porous filler, introducing the batch so formed into a mold puffed by heat to a highly porous product, having a paper lining and there heating it 7" and having a facing held in place by the inuntil the material puffs to a porous cotumesced binder. herent product, and adheres to the paper.

6. A wall-board characterized by the te- 15. The process of making wall-board nacity between the core and the facing comhaving a high degree of tenacity between prising a mixture of sodium silicate and the core and the facing which comprises crushed dolomite pufi'ed by heat to a highly mixing an alkali silicate with a filler, inporous product and having a paper facing trodncing the batch so formed into a mold held in place by the intiunesced binder. having a paper lining and there heating it 7 A wall-board characterized by the teuntil the material puffs to a porous coherent 13 nacity between the core and the facing eomproduct, and adheres to the paper. 50

prising a mixture of an alkali silicate, a filler, 16. The process of making wall-board and a soap, pufi'ed by heat to a rigid mass, having a high degree of tenacity between and having an adherent facing. the core and the facing which consists in 8. A wall-board characterized by the temixing an alkali silicate with a filler, intronacity between the core and the facing coinducing the batch so formed into a mold prising a mixture of alkali silicate, a min lined with aper. and there heating until eral filler, and sodium oleate, piifl'ed and the materia pufis to a weight less than hardened by heat, and having an adherent 62 ,4 lbs. per cu. ft. and adheres to the aper. facing, 17. The process of making walloard 9. A wall-board characterized by the tehaving a high degree of tenacity between nacity between the core and the facing comthe core and the facing which consists in prising a mixture of an alkali silicate and mixing alkali silicate with a mineral filler, about 607 of a crushed dolomite based on introducing the batch so formed into a mold the wet weight of the mixture, puffed by heat lined with paper, and then heating at about to a rigid mass, and having an adherent fac- 150 C. until the material puffs and harding. ens to a rigid porous mass and adheres to 10. A wall-board characterized by the tethe paper. nacity between the core and the facing com- 18. The process of making wall-board prising a mixture in parts by weight of 39% having a high degree of tenacity between 42.5 136. sodium silicate solution, 58% powthe core and the facing which consists in dered dolomite, 2.9% fine sawdust, 0.1% somixing an alkali silicate with a filler to diuin oleate puffed by heat to a porous body, form a batch of dough-like consistency, inand having an adherent facing of paper. troducing the batch into a mold lined with 11. The process of making wall-board paper and heating at about 150 C. for having a high degree of tenacity between about 30 minutes to puff and harden the W the core and the facing which comprises batch; and cause it to adhere to the paper. mixing an intinnescent binder with a filler, 1.9. The process of making wall-board subjecting the batch so formed to heat while having a hi h degree of tenacity between confined between paper liners until the mathe core an the fac ng wh ch consists in tcrial puffs to a porous coherent product mixing an alkali silicate with a mineral and adheres to the paper. filler to form a batch of dough-like consist- 12. The process of making wall board ency, introducing the batch into a mold having a high degree of tenacity between lined with paper and heating at about 150 the core and the facing which comprises C. for about 30 minutes to puff and harden mixing sodium silicate with a filler, who the batch; and cause it to adhere to the H diicing the batch so formed between paper paper. liners and then heating by contact with hot 20. The process of making wall-board lates until the material pufi's to a porous having a high degree of tenacity between coherent product and adheres to the paper. the core and the facing'which consists in 13. The process of making wall board intimately mixing an alkali silicate with it having a high degrceof tenacity between filler and a soap, introducing the batch so the core and the facing which comprises formed into a mold lined with paper and mixing sodium silicate with crushed doloheating to puff and harden the batch, and mite, introducing the batch so formed in a cause it to adhere to the paper. relatively thin layer between paper liners, 21. The process which consists 111 ntiand then confining the material and subjectmately mixing about 2.7 parts alkali s licate ing to heat until the material pufis to a with about 4.0 parts crushed dolomite by porous coherent product and adheres to the weight, mixing the batch to adoughy consistency, introducing it into a metal mold aper.

05 p 14. The process of making wall-board and there heating at about 150 Cafor about I Rh 1 .1 i

5 the core an thirti minutes to puff and harden said being of greased metal, and heating to ufi doug and cause it to adhere to the having a high degree of tenacity between mixing an alkali silicate with a filler, in-

troducing the batch so formed into a mold lined on one face with paper, the other face aper. and harden th 22. The process of making walloard to the paper.

e batch and cause it to ad ere 10 In testimony whereof we aflix our sigthe facing which comprises natures.

HOWARD F. WEISS. RALPH FORBUSH NORRIS.