US1325883A - Waterproof plaster-board and method of making same - Google Patents

Description

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muted Dec. 23, 1919.

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JAMES P. SEXTON, OF LOS ANGELES, CALIFORNIA.

WATERPROOF PLASTR-BOARD AND METHOD 0F MAKING SAME.

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i To all whom it may concern Be it known that I, JAMES P. SEXTON, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California,lhave invented new and useful Improvements in Waterproof Plaster-Board and Methods of Making Same, of which the following is a specification.

This invention relates to plaster board, plaster lath, and like articles, which comprise a body of plaster or other plastic or cementitious substance and one or more facing sheets of paper or the like; and the invention further articularly relates to such an article in which the paper facing sheets are waterproofed.

Accordlng to my invention the paper facing` sheets may 'be waterproofed in any desired manner; in a typical case, as hereinafter described, they may previously be waterproofed with a bituminous substance, such as tar. 1n typical instances I use what is commercially known as tarred paper or tarred felt; being preferably a soft finished, tarred paper, in which the aper is thoroughly impregnated with tie waterproong substance. f

lln the use of such waterproofed papers, it has been impracticab-le or impossible to join the plastic substances with the waterproofed paper. The very fact that the paper 1s waterproofed makes it Very difficult to form a bond between the moist plastic substance and the paper. This is particularly true where the plaster is not bonded to the paper by a mechanical bond of some sort. 1Where the paper and plaster are mechanically bonded, a waterproofed paper can, and has been, and is now, usedy by me in such construction yas is shown by my Patent No. 1,115,593, November 3, 1914, and reissued June 5, 1916, No. 14,148., and shown also in the following named patents:v plaster lath, No. 1,205,399, Nov. 21, 1916; plaster lath, No. 1.205,360, November 21, 1916; and applications as follows: method of making plaster lath, S. N. 129,650, Nov. 6, 1916; plaster lath, S. N. 187 ,331, Aug. 21, 1917.

1n such forms as herein referred to, one or both of the face sheets may be mechanically bonded. And my present invention may be applied to such mechanically bonded structure as Well as to a plain plaster board or the like.

For the purpose of fully explaining my present invention I illustrate herewith, in

Specication of Letters Patent.

Patented Dec. 23, 1919.'`

Application mea December 19, 191%. serial No. 207,856.

the accompanying drawings, a plain plaster board and a plaster lath which is known commercially as buttonlath; Figure 1 belng a section showing the structure of a plam plaster board; and Fig. 2 being a similar structure showing the structure of suelta plaster lath.

Such plaster boards and plaster laths are commonly made by interposinga body 10 of plastic substance between two sheets of paper or other fibrous substance, shown at 11 and 12. In the case of the plain plasterboard, both these sheets 11 and 12 are plain papers; while in the case of the plaster lath both facing sheets may be in the form shown at 12 in Fig. 2, with apertures at 12, allowing protuberances or buttons 10a to be formed of the plaster body 10; or one of the sheets may be in this apertured form and the other, as shown at 11, may be in plain form. Regardless of any peculiar shaping of the facing sheets, and whether or not there is a mechanical bond between the plaster and the sheet, my method of bonding the waterproofed sheet to. the plastic body may be used.

It is now the common practice to manufacture such plaster boards and the plaster laths by continuously laying a layer of moist or unstable plastic or similar substance upon a contlnuous length of paper and then laying another continuous length of paper over the plastic layer; suitable pressure being applied to press the plastic layer out into a uniform thickness. The papers used may be waterproofed in any manner, preferably waterproofed with a substance which melts or becomes soft at a fairly low temperature. Also, although this is not necessary, for the purpose of my invention the paper is preferably a relatively soft rough-surfaced paper, and is waterproofed with a bituminous substance. Now, as hereinbcfore stated, under ordinary circumstances the moist or unstable plastic substance which is laid between the sheets of such paper will not incorporate with the paper owing to the waterproof quality of the same. But I cause such incorporation to be made by suitably heating the plasterboard or plasterlath, either at the time of formation or at some time subsequent. Although I may cause the heating to take place during setting, I prefer to heat after partial or complete setting or during the latter stages of setting. I heat the plaster board or plasterlath to a temperature which is sufficient to cause the softening or melting of the bituminous waterproofing substance, but which is below the calcining temperature of the laster; and this temperature is typically a out 130o to 150 F. That is, this temperature is sufficient to cause the waterproofing substance to soften or melt, but it is not sulicient to deteriorate the plastic body. Heat of this degree of temperature need only be applied forca short 1nterval; it does not need to be ap lied during the whole of the setting or rying o eration of the plaster. By causing t e waterproofing substance to soften or melt, the pores in the paper are opened up so that (where the heating is done before the plaster sets) the moist or unstable plastic substance may permeate the paper to a certain extent by entering such ores; and (whether the heating is done be ore or after setting of the plaster) the melted or soft Waterproofing substance also penetrates the plastic substance to a certain extent. The substances are then allowed to cool, or cool and set, in their inter-permeated state. And by this means a bond is formed between the plastic body and the?- waterproofed paper facing, which bond 'extends over the whole of the surfaces of the body and paper, and causes the body and paper to be most thoroughly incorporated and bonded together. When the body and paper sheets are once bonded in this manner, the bond is as strong as or stronger than the plastic bod or the paper sheet itself. In fact, it is a most impossible to tear the paper sheet from the body without breaking or tearing one or both.

The foregoing description applies more particularly to the use of paper which has been previously waterproofed with a suitable substance. But it is not necessary that the paper be waterproofed before the application, of the plastic or cementitious substance thereto, as such waterproofing can be made to take place during the process offormation of the plaster board or the like. For instance,I have found it possible to rovide a plastic substance which, while it orms the body of the laster board, oont-ains in it a waterproo v g substance, such as certain kinds of glue, or bituminous substance or the like, which melt or soften upon heating and which will permeate the outer paper sheets. For instance, a greasy waterproofing substance may be used, in this instance, or in the instance heretofore explained in this specification, said substance softening or liquefying upon being heated and permeating the paper; and then, when solidifying, forming the same kind of bond between the paper and the plastic body as is hereinbefore explained.

It will -be seen that my invention is primarily a method of bonding which may bo applied to any form of plaster board or plasterlat-h, etc., Whether composed of one or more lastic bodies or sheets, and regardless of t e shape, etc., of those sheets. Applied to a plain plaster board it causes a thorough bond to be made where heretofore it has been impossible or highly diiiicult to make such a bond.; applied to a plaster latli .in which there is a mechanical bond, it adds its effectiveness by providing a bond which is co-extensive with the paper and plaster.

I do not limit my invention to the particular details herein described except as is `indicated by the following claims which are intended to cover the invention in its broad \as well as its specific aspects. Having described a preferred form of my invention, I claim:

1. The herein described method of making a waterproof plaster board or the like, which comprises the placement of an unstable plastic substance in contact with a porous sheet waterproofed with a material which is softened by heat and to which the cementitious substance is permeable and heating them to a temperature sufficient to soften the waterproofing of the sheet, to allow the waterproofing and the plastic substance to inter-permeate, and then allowing them to cool and set.

2. The herein described method of making a waterproof plaster board or the like, which comprises the placement of an unstable plastic substance in contact with a porous sheet waterproofed with a material which is softened by heat and to which the cementitious substance is permeable and heating them to a temperature sufficient to soften the waterproofing of the sheet but insulicient to deteriorate the plastic substance to allow the waterproofing and the plastic substance to inter-permeate, and then allowing them to cool and set. i

3. The herein described method of making a waterproof plaster board or the like, which comprises the placement of a moist plaster in contact with a sheet impregnated with a bituminous substance, and heating them to a temperature sufficient to soften said bituminous substance and insuicient to calcine the laster to allow the softened substance and t e moist plaster to inter-permteate, and then allowing them to cool and se 4. The herein described method of bonding a cementitious substance and a sheet waterproofed with a substance softened or melted by heat and to which the cementitious substance is permeable, which comprises placing the substance and sheet in contact, heating them to soften the waterprooffing substance to allow it to permeate the cementitious substance, and then allowing them to cool.

5. The herein described method of bonding a plaster and a paper impregnated with bituminous substance, which comprises placing the plaster in contact with the paper, and heating them to a temperature sufficient to soften the bituminous substance but insufficient to caloine the plaster.

6. The herein. described method of making a Waterproof plaster board or the like, Which comprises the placement of a water proofing capable of being softened by heat and an unstable plastic material which is permeable to the softened Waterproofing material in contact with a sheet permeable to the-softened Waterproofing material, and heating them to a temperature suiicient to soften the Waterproofing, to allow the Waterprooing to permeate the plastic material vthe plaster and the bituminous substance being incorporated by interpenetration with each other over their face of contact.

In witness that I claim the foregoing I have hereunto subscribed my name this 4th day of December, 1917.

JAMES P. SEXTON. Witness:

V. BERINGER.

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