US1669490A - Vulcanized pitches - Google Patents

Description

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PATENT OFFICE.

WALLACE SAVAGE, OF NEW YORK, N. Y.,

ASSIGNOIlR 1'0 SAVAGE-RUBBER CORPORA- TION', A CORPORATION OF NEW JERSEY.

VULCANIZED PITCHES.

Io Drawing. I

esters or oils and about 40 per cent resin like polymerized oil hydrocarbons. The socalled fatty acid pitches designated and sold in commerce as cotton seed foots, corn oil, beta oil pitches and the like, are 'made by the pyrolytic distillation of these oily still bottoms residues, a large portion of the free fatty acid content of which is superheated to volatilize and separate a yield-of low grade pyro-fatty acid distillate. These destructively distilled pitches may have a melting point of from 100 to 350 F., and penetration of 100-0 mm., at 77 F., according to the extent of pyrolysis they have undergone. They are asphalt-like in most of their physical properties, action, treatment and application, but are dissimilar to asphalt chemically due to their fatty origin.

The present'inizfention has particular reference to the production of improved vulcanized fatty acid pitch products characterized by their abillty to more completely, rapidly and spontaneously recover their original size and shape after deformation than any known pitch product familiar to those experienced in the art. The vulcanized pitch herein described is suited for use as a packing material for liquid, vapor or 7 gas tight joint seals, especially in large engmeerlng structures, such as are used in the construction of roads, roofs, tanks, dams, conduits, subways, sewers and the like.

candle tar, the pitch made from the still bottoms residues from distilled stearines, have been known in the arts formore than forty years and were first commercially used and known under the name of Oallenders pitch. The same type of products including paint solutions of it were later described in the art. Candle tar, as its name implies, is

derived from rigid waxy fats ofthe type used in the manufacture of stearine, candles. It yields a. vulcanization product having rties influenced by the characteristics esefe'tsnnd therefore having much less vulcanized residues are that they are pliable Application fled January 17, 1922. Serial No. 529,963.

elasticity than the products obtained from residues or pitches derived from oils chem-. ically characterized as unsaturated, or having double bonds.

I have discovered that when soft dryin oil still bottoms residues from fatty acid refining are vulcanized with more than seven per cent sulphur at from 300 to 400 F., a new highly elastic congealed pitch product, resembling soft rubber in. its physical properties, is obtained. If the residue is first partially hardened by pyrolytic treatment, blowing air or steam through its melted mass, or dissolving harder bitumens in it, a firmer body will be obtained in the vulcanized product. The higher the iodine value the softer the product will be due to the action of the double bonds on the texture of the hydrocarbon. When pulled, these products stretch considerably and when released, return directly to their original shape. They give under displacing pressure and recover their form as released. These vulcanized residues are firmer than the vulcanization products made from the oils from which" the fatty acids were originally obtained and more closely resemble rubber than the so-called rubber-substitutes or vulcanized oils. The distinctive properties of these at 32 F., are self-healing when ruptured and have a melting point of 360 F., when fully congealed and cured. By, partially subjecting the residue to any of the hardening processes known in the arts such as pyrolytic distillation, air blowing, blending with previously hardened fatt acid pitches or natural mineral bitumen hardeners, such'as grahamite or gilsonite, I have T011753 that all intermediate stages between extremely soft and vulcanite hard rubber like proper- Kerite products comprising vulcanized ties can be obtained from the vulcanized residue. Also these various stages of pliancy in the vulcanized productcan be obtained by softening a hard pyrolytically distilled fatty acid pitch by blending therewith any flux such as solvent mineral or organic oils, fatty acids or their glycerides to..obtain' the equivalent physical properties in the alternatemanner above cited, prior to vulcanization.

In the process of vulcanization, I have found it convenient toadd gradually about two-thirds of the sulphur required for the process with agitation to free the hydrogen sulphide as aimed. Thus semifinished product that can be stored and transported at any temperature is obtained. The final takes place apparently regardless of either thermal, cata ytic or time conditions. Amounts of sulphur as high as sixty per cent of the mass of the vulcanized product can be used, the excess of uncombined sulphur forming an inert filler of visible crystalline grains. Free sulphur in excessive amounts givesa product having less desirable properties than an equivalent one having a mineral of a structure superior to v .the sharp rhombi'c or prismatic sulphur crystals. Accelerators, such as aniline, thiocarbanil de, zinc oxide or magnesia contribute to the speed of vulcanization and imrove the quality of the product. Comined sulphur such as antimony sulphurete, sulphur chloride and equivalent vulcanizing agents give products having peculiar characteristics similar to those obtained by their use with rubber gum. In fact most I of the processes and materials of vulcanization and compounding as practiced in the rubber-art can be applied to fatty acid residue treatment with success. Fillers such as clays, soapstone I magnesia, ochre, barites, asbestos, "cotton inters, mineral wool, paper round wood zinc oxide, gas black, lamp lfiack, glue and rubbers, rubber ms, rubber substitutes and similar nateria s may be especially mentioned as giving. homologous compounds with fatty acid still, bottoms residues-to those obtained with rubber gums which are familiarly known in the art. The function of fillers is to act as a brake on displacement under stresses. Fiber fillerssuch as asbestos resist both compression and tension, while powders such as carbon black counteract compressive loads, formin a supportin skeleton structure within t e compoun Part of-the required sulphur of vulcanization generally called free sulphur in rubber parlance performs an identical function so. that the compounding of-fillers in a compound is actually substituting this class of material for the inert filler phase of sulfo'rmaldehyde, mineral phur. that would be obtained by the use of over ten per cent sulphur in the product.

The preferable manufacturing procedure is to heat about 3500 lbs., of fatty acid st-ill bottoms residues resulting from the treatment of cottonseed, 'corn, soy-a bean, garbage reuse or like oils in the manufacture of fatty acids to 300 F., in an autoclave supplied with a suitable agitator. Into the mass there are then incorporated 10' lbs. of thin carbanilide, 20 lbs. zinc oxide, 250 lbs. of melted sulphur, 400 lbs. of asbestos fibers and 80 lbs. of powdered magnesia. Grahamite may or' may not be added in amounts from 100 to 400 lbs. according to the requirements as to hardness. The autoclave is sealed, and the ten'ipc rature increased to 370 F. When the product has ceased foaming and congealed, it is blown out into forms and worked into shape while plastic.

After cooling below 1&0 1*. the congealedproduct takes a permanent set. It can be cut into boards andother simple shapes after it is cold. The scrap is returned to the next autoclave batch and worked over. If 100 lbs. of the sulphur is held out, it may be added to the product upon cooling to 300? F., and a semi-vulcanized product obtained which will congeal upon heating to 37 0 F., for a few minutes.

While I have described in detail the preferred materials and proportions used in my vulcanized products, it is to be understood that known chemical and physical equivalents of the materials used may be employed,

all without departure from the spirit of my invention or the scope of the,subjoined claims. g

Having described my invention, I claim: 1. A soft rubber like composition comprisprising fatty acid still bottoms residueing fatty acid still bottoms residue prod-" ucts vulcanized 10o products vulcanized with the aid of thiocaranilide and zinc oxide. I

4. A soft rubber like composition coinprising fatty acid still bottoms residue products vulcanized with the aid of an organic accelerator. v,

In testimony whereof I afilx my'signature.

" WALLACE SAVAGE.