US1427911A - Plastic composition - Google Patents

Description

latented Sept. 5, 11922 UNITED STATES LINWOOD r, RICHARDSON, or mnwauxnawrscousm, assrenon -ro inn 0mm.-

HAMMER MFG. 00., O1 MILWAUKEE, WISCONSIN, A. CORPORATION OF WISCONSIN.

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No Drawing.

To all whom it may concern:

Be it known that I, ARDSON, a citizen of the United States,-residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Plastic Compositions, of which the following is a vents therefor, such, for example, as the composition proposed in the patent to William H. Steinberg No. 1,233,416, of July 17, 1917. I

In the manufacture of such compositions I have found that the use of binder-constituents containing fatty materials tends to lessen the water resisting properties of the product, while on the other hand, certain constituents ofthis class, such as stearin pitch, have properties which render the use thereof otherwise very desirable. For example, the use of stearin pitch as set forth in the Steinberg patent, tends to increase the hardness, density and mechanical strength of the product.

Further, I have found that in compositions of the aforesaid character wherein the filler employed contains basic substances, the tendency mentioned is largely due to the re- "action of the fatty materials with such basic substances, and the present invention has among its objects to curtail the loss of water resisting properties of the product from this cause. Also, theinvention has among its objects to provide a heat treatment for the product which will further minimize such tendency of the fatty materials of the binder constituents.

Compositions made in accordance with the present invention may comprise various alternative constituents, but it is preferred to employ those proposed in the Steinberg patent, and for the purpose of more fully and clearly explaining the present invention the production of a composition from such constituents will now be described.

.Following the Steinberg patent, it 1s pro- LINWOOD T. R101? Application-filed December 24, 1917. Serial No. 208,538.

posed to use a filler comprising a mixture of comminuted asbestos and sulphur and a binder formed by mixing coal tar pitch and stearin pitch in, the-presence ofheat (400 to 500 F.) for precipitation of the free carbon thereof, then, while the mixture is 'hot, adding thereto an animal or vegetable oil, ca-

PATENT" OFFICE.

pable of vulcanization or polymerization,

preferably castor oil, then drawing off and cooling the supernatent fluid and finally adding thereto a benzol. f

However, it is now proposed to subject the asbestos to one of the following alternative treatments or to some other treatment for the purpose hereinafter set' forth, before using the same.

(a) subjecting the asbestos to the action of an acid, suchas hydrochloric acid, whereby the basicity thereof is neutralized with the formation of soluble salts, then washing the asbestos with water for removal of the soluble salts and finally drying the asbestos.

(b) subjecting the asbestos to an acid, such as phosphoric acid, for formation of insoluble salts, and then drying the same.

(a) Mixing the asbestos with a body cavolatile solvent, preferably pable of furnishing silicic acid (ground flint,

infusorial earth orprecipitated silicic acid) is probable that the same result might be accomplished in other ways. For instance, the elimination or neutralization of the basic substances in the asbestos could doubtlessly be accomplished by subjecting the latter to the action of various gases, such as carbon dioxide, or sulphur dioxide.

After such treatment of the asbestos it is proposed to mix the sulphur therewith by any convenient method and to then mix the filler and binder preferably in a cold state, as proposed in said Steinberg patent, to produce a granular but plastic compound to be molded.

Finally it is proposed to heat treat the molded product to increase the heat resisting properties thereof; the degree of heat employed for such treatment being regulated according to the final heat resistance desired of the product. Also, it is proposed to so heat treat the product in an atmosphere of steam or other non-oxidizing gas inert toward the same, the gas or steam being utilized to protect the product from access of air, especially at elevated temperatures of 250 F. or more. And in this connection it it to be understood that this heat-curing step is distinct from and additional to the aforesaid treatment of the asbestos prior to mixing.

Further, it is to be understood that the proposed heat treatment might be omitted and that the product might be finally treated in other ways, as by the baking step previously used. However, the proposed heat' treatment is recommended as the wet strength curve of the product will then very closely approximate the dry strength curve .of the product if baked, whereas the baking process tends to curtail the wet strength of the product. Also, the proposed treatment tends to increase the heat resistance of the product.

\Vhat I claim as new and desire to secure by Letters Patent is:

1. The herein described process, for curtailment of the effect of water on plastic compositions formed of a binder containing fatty materials and a filler containing basic ingredients, consisting in subjecting the filler, prior to mixture with the binder, to a neutralizing treatment rendering the filler ingredients non-combining as regards the fatty materials of the binder.

2. The herein described process, for ourtailment of the effect of water on plastic coinposltions formed of a binder containing fatty materials and a filler containing basic ingredients consisting in mixing with the filler a body capable of furnishing silicic acid and.

subjecting such mixture to steam under pressure, prior to mixing the binder and tiller.

3. The herein described process, for plastic compositions formed of a binder containing fatty materials and a filler containmg basic ingredient-s, consisting in subjecting the filler to a treatment for renderin its ingredients non-combining with the fatty materials of the binder, then mixing the filler and binder, and finally heat treating the product in an atmosphere of gas inert toward the product.

4. A composition of the character set forth comprising a binder having stearin pitch as an ingredient thereof, and a filler of asbestos treated to withstand the reactive eifects of the fatty material of said binder, said composition being heat treated in an atmosphere of inert gas for increased resistance to the effect of water.

In witness whereof, I have hereunto subscribed my name.

LINWOOD T. RICHARDSON.