DE549759C - Process for converting rubber - Google Patents

Description

GERMAN EMPIRE

ISSUED ON
APRIL 30, 1932

REICH PATENT OFFICE

PATENT LETTERING

CLASS 39 b GROUP

I. G. Farbenindustrie Akt.-Ges. in Frankfurt a. M. *)

Process for converting rubber

Patented in the German Empire on October 22, 1930

It is known to treat rubber with sulfuric acid, organic sulfonic acids, etc. at temperatures above 120 ^0, where dark colored transformation products are formed which have balata, gutta-percha or shellac similar properties.

It has now been found that you can particularly valuable conversion products of Rubber can be obtained, if you have dissolved rubber or in inert solvents rubber-like polymerization products of butadiene hydrocarbons with carboxylic acid anhydrides treated in the presence of mixed organic-inorganic acid anhydrides or or and sulfocarboxylic acids.

Examples of inert solvents for the rubber are: hydrocarbons (e.g. benzene) and especially their chlorine derivatives (such as chloroform, carbon tetrachloride, Trichlorethylene, monochlorobenzene, monobromobenzene). Suitable carboxylic anhydrides are, for. B. acetic anhydride, chloroacetic anhydride, Propionic anhydride, benzoic anhydride, phthalic anhydride, etc.

Suitable mixed organic-inorganic acid anhydrides are: acetic acid-sulfuric acid anhydride (acetylsulfuric acid), chloroacetylsulfuric acid, propionylsulfuric acid. Sulfoacetic acid, sulfopropionic acid, chlorosulfoacetic acid and sulfobenzoic acid may be mentioned as sulfocarboxylic acids. One works suitably at room or moderately elevated temperature, however, can also work at temperatures above 120 ^0th

It has been shown that instead of a mixture of the carboxylic acid anhydride with a mixed organic-inorganic acid anhydride or with a sulfocarboxylic acid also a mixture of carboxylic acid anhydride and an oxygen-hard mineral acid, ζ. As sulfuric acid and the like, can use, since the mixed anhydrides mentioned or the sulfocarboxylic acids themselves, through the action of the oxygen-containing inorganic ones Acid form on the carboxylic anhydride after a while.

The conversion products obtained are amorphous, and depending on the purity of the one used Rubber slightly colored to colorless. They are insoluble in water, alcohol, ether and acetone, but in aliphatic and aromatic hydrocarbons and their chlorine derivatives are readily soluble. The conversion products are when heated three-dimensional, and, like celluloid, can be processed into artificial masses. To the Some of them can also be used as an adhesive. Let the conversion products harden by prolonged heating. Depending on

*) The patent seeker indicated the following as the inventors:

Dr. Heinrich Ilopff, Dr. Friedrich Eb el and- Dr. Karl Wolf in Liuhvigshaf en a. Rh.

the duration of the heating and the temperature used are balata, gutta-percha or schelladi-like products obtained in the usual solvents for rubber to solve. The solutions of the conversion products hardened in this way can be used for themselves or in the. Mixture with the usual paint components Use as a binder for paints. You can, even those with solutions

ίο the non-hardened transformation products Subsequently harden the coatings produced by heating.

The products obtained can also be used on their own or in a mixture with other substances,

z. B. natural rubber, for the production of waterproof coatings on textiles and the like or used to impregnate textiles.

Example 1 ^r

Dissolve 5 parts of rubber in 100 parts of chloroform, are 10 parts of acetic anhydride (or propionic anhydride) containing 2.50 / 0 Acetylschwefelsäure (or Propionylschwef elsäure) is added, mixed well and left for 24 hours at 15 ⁰ stand. The red-brown colored solution is then washed neutral. After the chloroform has been driven off, a white mass remains, which is e.g. B. can be rolled into leather-like skins and becomes malleable ^{at So 0.}

Example 2

ι ο parts of rubber and 100 parts of trichlorethylene are treated with thorough mixing with 20 parts of acetic anhydride, which contains 2.50 / 0 sulfoacetic acid, for 24 hours. The isolated in the direction indicated in Example 1, product is a bright friable mass that is plastically on heating to 130 ^0th The properties of the product are not changed by heating.

Example 3

5 parts of rubber are kneaded together well with 20 parts of carbon tetrachloride and then 25 parts of chloroacetic anhydride are added over the course of a few hours while continuing to knead, which contains 1.50 / 0 chloroacetylsulfuric acid. The mass becomes brown and thin. The almost preserved after processing white reaction product turns into a light brown when heated to 2oo ° with melting Product that is extraordinarily hard and tough after cooling. It delivers e.g. B. with benzene a thin liquid solution, which when it dries up a hard, shiny, very leaves a well-adhering film.

Example 4

10 parts of a non-distillable undecomposed polymerization of butadiene are swollen in 50 parts of chloroform, containing 10 parts of acetic anhydride, the ioO / ₀ · sulfoacetic acid, homogeneously mixed and allowed to stand for 24 hours at room temperature. The brown, thin liquid solution obtained is worked up according to Example 1 and gives light-colored, tough and hard products which become malleable when heated to 100 °.

Claims (1)

Claim: Process for converting natural rubber or rubber-like polymerisation products of butadiene hydrocarbons which are dissolved in inert solvents, characterized in that that the rubber, etc. are mixed with carboxylic acid anhydrides in the presence of 'organic-inorganic acid anhydrides or or and sulfocarboxylic acids treated.