US2086862A - Wallboard - Google Patents

Description

Julygl, 1937.

J. FLETCHER 2,086,862

WALLBOARD Filed Aug. 22, 1955 JWM/Ha Patented July 13, 1937 2,086,862

, UNITED sTATEs PATENT OFFICE WALLBOARD John Fletcher, Kenmore, N. Y., assigner to Plastcrgon Wall Board Company, Buialo, N. Y., a corporation of New York Application August 22, 1935, Serial No. 37,351

12 Claims. (Cl. 91-68) This invention relates to wallboard, and parmum expansion and contraction when assemticularly to a composition wallboard having as a bled as part of a wall construction, and with v part thereof a sheet of open pore fiber insulating which the cracks between abutting edges of adboard. Heretofore, attempts have been made to jacent sheets may be easily lled in a manner 5 apply a plastic gypsum mixture to a face of suchr to seal the cracks and provide a durable, conopen pore ber insulating board, but the product tinuous gypsum finish from one sheet to the other.

obtained has been unsatisfactory because it has Various other objects and advantages will be been impossible to avoid cracking of the gypsum apparent from the following description of excoating during handling of the sheet, and beamples of the invention, and the novel features cause of the unequal expansion and contraction will be particularly pointed out hereinafter in 10 of the coating and open pore board. The gypsum connection with the appended claims.

mixtures heretofore used for this purpose have In the accompanying drawing:

' been brittle, with a tendency to disintegrate and Fig. l is a sectional elevation through a por- Separate from the porous and fibrous surface of tion of asheet of Wallboard constructed in accord- 5 the open pore board during transportation and ance with this invention; and 15 handling, prior to and during the application of Fig. 2 is a sectional elevation through a part the board to a wall construction. A gypsum surof a Wall construction utilizing this improved face or face on `a wallboard is often very deboard, and illustrating the manner of filling the sirable, but because of the expansion and concracks and forming a continuous gypsum iinish traction of the flberboard, it is also dicult to between adjacent sheets of said board. keep the cracks between abutting edges of ad- In accordance with this invention Iimpregnate jacent sheets of such board filled with a gypsum a sheet of open pore ber insulating board with mixture so as to form a continuous union bea suitable stiiening agent, and then apply to a tween the 4gypsum coatings on the adjacent or' face of such board a plastic coating containing abutting sheets. When the sheets contract, the calcined gypsum and an adhesive. S0 that the 25 lling tends to separate from the edge of one adhesive of the coating will adhere firmly to the sheet or the other and form an objectionable stiffened board. By impregnating the board crack in the gypsum surface or coating. with a stiffening agent, its expansion and con- An object of the invention is to provide an imtraction is greatly restricted, which reduces the 0 proved wallboard which will have a gypsum ntendency of the gypsum coating to crack or sep- 30 ished surface, With which the development of arate from the board. Preferably, I impregnate cracks and disintegration during handling oi' a sheet of open pore fiber insulating board with the board will be substantially prevented, with a readily soluble Sienllg resin, and this mwhich separation of the gypsum coating or finish pregnation, in Some instances, is preferably dis- ;5 from the board will be substantially prevented, tributed throughout substantially the entire 35 which will have maximum strength, rigidity and board, although 43some of the desirable results durability, which will have substantial resistance may be obtained to Some extent through imto destructive insects, and which wi11 be relapresu-ation only 0f a Surface layer of the board. tively simple, and inexpensive. I prefer to carry out the impregnation by apl0 Another object of the invention is to provi-de plying t0 the' board a Solution of the resin in a 40 5 mixture to provide a continuous gypsum surface an improved wallboard having a gypsum coating volatile solvent, because I have found that by or huish, with vwhich the cracks between abutusing the resin Solution. great Strength and rigidting edges of adjacent sheets as applied to a, ity of the board is obtained. To a face of this wall construction, may be lled with a gypsum board, Which Should be an impregnated facial apply the coating of a plastic mass containing 45 from one sheet to the other, with which the de- Calcined gypsum with an adhesive, and the most velopment of cracks in the gypsum coating 0r satisfactory adhesives are resinous solutions confinish at the abutting edges of the sheets will be taining a solvent for the resin with Which the substantially reduced or prevented, and with berboard is impregnated. The inclusion in the 30 which greater adhesion between the crack filler gypsum mixture f a quantity 0f fbI'OllS, DOII- 50 and the boards may be obtained. metallic minerals such as fibrous types of am- Another object of the invention is to provide an phibole, serpentine and chrysotile, is advantaimproved method of making wallboard, which geous and adds materially to the strength and will produce a superior Wallboard having a gyptenacity of the coating. When `a plastic mass sum coating or finish, maximum strength, minior mixture of calcined gypsum, with or without added fibers, and such a resinous solution is applied to the impregnated board, the solvent in the resinous solution of the plastic mass, where it contacts with the impregnated board, will soften or partially dissolve the resinous impregnating agent of the board at approximately the surface of the board, and then when the solvent is evaporated or absorbed a very rm union between the coating and the board is obtained.

The resinous adhesive used in the gypsum mixture greatly increases the strength, durability, and rigidity of the gypsum coating, because it causes greater cohesion between the particles in the mixture of the coating. 'I'he board, because of its impregnation with the resin, will be largely unaffected byatmospheric and temperature changes and, therefore, the tendency of the gypsum coating to crack or chip off during use will be reduced or prevented. The tendency of the coating to crack and chip is also reduced by the fibrous non-metallic minerals which may advantageously be included with the gypsum in the lcoating mixture.

Among the resins which are suitable'for impregnation of the berboard, as well as for mixture with the calcined gypsum forming the coating, may be particularly mentioned the natural resins such as shellac, rosin, gum accroids, manila gum and kauri gum, and among the synthetic resins may be particularly mentioned the phenol-aldehyde resins, the polybasic acid-polyhydric alcohol, fatty acid type of resins, and the urea-aldehyde type of resins. The solvent used for the resin with which the board is impregnated should preferably be a readily volatile solvent. Alcohol is a very satisfactory and inexpensive, yet volatile, solvent for this purpose.

As one example of the invention, a sheet of open pore fiber insulating board is thoroughly impregnated with a solution of one of the above mentioned resins vin alcohol. Then to a face of such an impregnated sheet I apply a coating, in plastic form, which may be prepared as follows:

Approximately parts by weight of dry calcined gypsum is mixed with 50 parts of a resin solution containing 20 parts of shellac-and 30 parts of alcohol. 'Ihis plastic gypsum mass may be applied to a face of the impregnated board by trowel or brush and levelled out on the board. The thickness of the coating may be whatever is desired, but I have found that it may vary for practical purposes between 1,@4 of an inch to ys of an inch Without-danger of the surface coating cracking. Preferably, the impregnated board is dried somewhat after impregnation, although with a readily Volatile solvent, suflicient air drying may occur after the impregnation before coating can be applied thereto.

The alcohol or other solvent in the gypsum plastic coat will, wherever itcontacts with the fiber board, soften or partially dissolve the alcohol soluble resin with which the board was impregnated, and then as the plastic mass or coating hardens and the alcohol or solvent evaporates, there will be a firm and unitary union between the resin of the gypsum coating and the resin With which the board is impregnated. In addtion, the resin in the gypsum coating will increase the cohesion between the gypsum particles, and thus provide a very hard gypsum finish or coating on the board which adheres to the board with a maximum of firmness. Any of the other resins may be employed in a similar manner, both for the impregnation of the board and for the preparation and application of the gypsum coating.

' When the improved gypsum wallboard is applied to a wall construction, the sheets are usually secured to a wall or basicl structure by nails driven through the board into the basic structure. In Fig. 2 I have illustrated a simple manner by which this improved board may be attached to a basic structure without the objectionable feature of having the attaching nails visible on the exterior of the wall. Referring now to Fig. 2, the portion of a Wall construction in which two sheets I0 of open pore, fiber insulating board that have been impregnated and coated with a gypsum iinish or coating in accordance with this invention, are brought together against a basic structure I2 so as to approximately abut edge to edge and lie flat against the basic structure I2 along the abutting edges of the improved board.

A plurality of nails I3 may then be driven through the sheets III into the basic structure I2 at the abutting edges of the sheets, the nails being preferably started adjacent the base of the coatings and driven somewhat diagonally through the impregnated open pore berboard sheets I0 into the basic structure I2, as shown clearly in Fig. 2. nails will not pass through the gypsum finish or coatings on the impro-ved board, but largely through the impregnated basic sheets IIJ. Since the impregnated sheets now have greater strength and rigidity, it is possible to pass the nails through the end edges of the impregnated sheets and still obtain a. satisfactory attachment between the board and the basic structure I2.

The crack or space between the adjacent edges of the improved wallboard may then be lled with a plastic mass I4, which preferably should contain calcined gypsum mixed with an adhesive such as a resinous solution containing a solvent for the resin with which the sheets I I! are impregnated, and therefore the mass I4 may advantageously be of the same plastic composition as that of the gypsum coating I I on the impregnated board. The solvent in the plastic mass will soften, and form a firm union with, the resin with which the open pore sheets I0 are impregnated and also the resin of the coatings I I. If it becomes necessary to drive attaching nails I5 through a face of the coated sheets, the nails are preferably countersunk at their heads and the countersunk holes I6 then filled with a plastic mass similar to the crack ller I4.

It will be understood that various changes in the details and materials, which have been herein described and illustrated 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. An improved wallboard comprising a sheet of open pore, ber insulating board impregnated with a stiiening resin solution, and having an adherent surface coating of a mixture containing calcined gypsum and a resin solution in which the impregnating resin is soluble.

2. An improved wallboard comprising a sheet of open pore, ber insulating board impregnated with an alcohol soluble stiffening agent, and having a hardened surface coating which has been` applied thereto while plastic and containing calcined gypsum mixed with an alcohol-containing, resin solution, whereby the alcohol in the applied plastic coating will unite the coating firmly to the open pore 'board through the impregnating agent therein.

With this arrangement the 3. The method of making an improved wallboard which comprises impregnating a sheet of open pore, fiber insulating board with a solution 'ing resin is soluble, whereby when the plastic coating hardens the resin intermixed therewith increases the cohesion between the gypsum particles and the solution in the plastic coating will soften and formv a firm union with the resin impregnating the berboard. A

4. The method of making an improved wallboard which comprises impregnating a sheet of open pore, fiber insulatingboard with a solution of a stiffening resin in a volatile solvent, substantially drying the impregnated board to harden the resin therein, and then applying to a face of the impregnatedsheet a plastic coating containing a mixture of calcined gypsum with a resinous solution in which the'impregnating agent is soluble, and then hardening the coating, whereby the resin intermixed with the gypsum will increasey the cohesion between the gypsum particles and the solution intermixed with the resin will soften and form a union between the resin-con,- taining coating and the impregnatingresin ofthe sheet.

5. The method of preparing an improved wallboard which comprises impregnating a sheet of open pore, ber insulating board with an alcohol solution of a stiiening resin, and .then applying to a face of the impregnated sheet a coating of a plastic mass containing a mixture of calcined gypsum with a resinous solution containing alcohol, and then hardening said coating.

6. The method of preparing an improved wall- V board which comprises impregnating a sheet of I' soluble stiiening resin, and then applying to a lface'of the impregnated sheet, a coating of a plastic' mass containingv calcined gypsum mixed with a solution of shellac in alcoholl and then hardening said coating.

8. The method of making an improved wallboard which comprises impregnating a sheet of open pore, fiber wallboard with an alcohol soluble resin to stiffen said sheet, and then applying to a face of the impregnated sheet. a. coating of a plastic mass containing calcined gypsum, shellac and alcohol approximately in the proportions of 100 parts by weight of dry calcined gypsum and 50 parts of a resin solution containing 20l parts of shellac and 30 parts of alcohol, and then hardenlng the coating.

9. An improved wallboard comprising a sheet of open pore, ber insulating board impregnated with a stiffening resin which is soluble in a volatile solvent, and having on a face thereof, a coating containing a mixture of calcined gypsum with a resin solution containing a solvent for the impregnating resin, whereby said solvent in`the coating mixture will softenv and form a union with the impregnating resin in-said sheet.

10. An improved wallboard comprising a sheet of open pore, ber insulating board impregnated with an alcohol solution containing a stiifening resin, and having on a face thereof a coating of Y a mixture, applied while plastic, containing calcined gypsum intermixed with an alcohol solution of a resin, whereby the alcohol of the plastic coating will soften the impregnating resin of said sheet and form a firm union between the coating and the sheet.

11. An improved wallboard comprising a sheet of open pore, fiber insulating board having at least a surface layer thereof impregnated with a soluble resin, and having on said impregnated surface layer, an adherent coating, applied while plastic, containing a mixture of calcined gypsum with a resinous solution including a solvent for thevimpregnating resin of saidsheet, whereby the solvent in said plastic coating will soften the impregnating resin on said surface layer of said sheet and form a irm union between it and the 4 resin in said coating.

12. An improved wallboard comprising a sheet of open pore, ber insulating board impregnated with a stiiening agent, and' having on a surface thereof a coating, applied while plastic, containing a mixture of calcined gypsum and a solvent for said agent.

^ JOHN FLETCHER..

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