SU956517A1 - Rubber stock based on liquid carboxyl-contaning rubber - Google Patents

Description

The invention relates to the rubber industry, in particular to vulcanizing rubber compounds from liquid rubbers with terminal carboxyl groups, and can be used for the manufacture of rubber products and potting compounds.

A known rubber compound based on liquid carboxyl-containing rubber, containing epoxy compounds as a vulcanizing agent and a catalyst for the interaction of polycarboxyl-containing polymer and epoxy compound. The catalysts used are the reaction product of a tertiary amine, aromatic or aliphatic oxide with alcohol and water taken in an equimolecular ratio l.

The disadvantages of such mixtures are the low rate of vulcanization (the process is carried out at 80 ° C for 24 hours), as well as the tendency of the obtained vulcanizates to thermal-oxidative aging as a result of the accumulation of quaternary ammonium bases of the fa disintegration under their influence of ester cross-links that form in the presence of epoxy resin and the described catalyst.

The closest to the one proposed is a rubber mixture based on liquid carboxyl-containing rubber. ka, comprising an epoxy resin and a curing catalyst, trioxymethyl phosphine, used, for example, in an amount of 2-8 parts by weight. on 100 ma.ch. liquid rubber 2.

The rubbers obtained from such a mixture are characterized by unsatisfactory physicomechanical properties: low resistance to bursting, breaking, and considerable residual elongations. In addition, the mixtures described need to be evacuated before curing to remove

20 moisture and volatile components.

The purpose of the invention is to increase the resistance to tearing and reduce the residual elongation of the vulcanizates.

25

The goal is achieved by the fact that a rubber mixture based on liquid carboxyl-containing rubber, as a catalyst for curing resin and rubber, contains a complex

30 compound tr boron fluoride with

di - or triethylamine in the following ratio of components, wt.h. Rubber100

Epoxy resin 20-40 The specified complex compound 2-10 The complex compound is synthesized from etherate of boron trifluoride and amines (di-, triethylamine, etc.) with an excess of one and a half times of boric trifluoride etherate.

Low molecular weight polybutadienes and copolymers of butadiene with vinyl monomers containing terminal or statically located carboxyl groups, epoxy resin, and boron trifluoride complexes with amine borazacs can be used as starting components in the mixture.

Examples 1-7. In order to obtain compositions in a mixer, liquid carboxyl-containing rubber SKD-1 is mixed until homogeneous. with terminal carboxyl groups, ED-20 epoxy resin and a complex of boron trifluoride with amine, are poured into molds and cured at a given temperature (100-120s). The composition of the mixtures, the conditions for vulcanization and the properties of the materials obtained are given in Tables 1 and 2. The properties of the proposed mixture and vulcanizates were compared with the properties of the known mixture and the properties of materials obtained as a result of its vulcanization.

The use in the composition of the proposed mixture of a complex of boron trifluoride with triethylamine, as can be seen from the data of Tables 1 and 2, allows more than 3 times as compared with

known mixture to increase the resistance to rupture of the vulcanizates. For example, the tear resistance of vulcanizates of mixtures of compounds 5 and b reaches 41 and 69 kgf / cm, respectively, while the tear resistance of vulcanizates of a known mixture is 15 kgf / cm.

At the same time, the vulcanizates of the mixture are lower residual elongations than the vulcanizates of the known mixture. Vulcanization proceeds at a relatively low temperature.

The advantage of the proposed mixture is also the fact that the process of its vulcanization is considerably simplified, since the mixture is not required to evacuate the mixture before vulcanization, but an obligatory one for vulcanization of the known mixture. Complex trifluoride

boron with an amine has no unpleasant odor inherent in trioxymethylphosphine and known mixtures.

The vulcanizates of the proposed mixture have improved deformation characteristics. The relative elongation of, for example, vulcanizates of mixtures 2-7 is 450-700%, while the relative elongation of the known mixture does not exceed 310%. When vulcanizing the rubber mixture in the presence of boron trifluoride complex with amines in the structure

; polymeric networks form ester bonds, and since the proposed mixture does not contain agents (tertiary amines) that cause the destruction of ester bonds, the vulcanizates based on the proposed mixture are characterized by high resistance to thermo-oxidative ablation. Respectively rubber products. LIA from the proposed mixture will be enhanced life.

Table

100 100 100 1рО 100

20 20 20. 30

20

100 30

100

.100 40 20

Boron trifluoride complex with Grietlamiom

Trioxymethylphosphine

Dimethylaminopheiol

The temperature of the vulcanization continued tab. one

1010

ten

table 2

Claims (1)

Claim A rubber mixture based on liquid, carboxyl-containing rubber, including epoxy resin and a resin and rubber curing catalyst, with the aim of increasing the tensile strength and reducing the residual elongation of vulcanizates from this mixture, the latter contains as a catalyst a complex compound of boron trifluoride with di- or triethylamine in the following ratio of mixture components, parts by weight: Specified Rubber100 Epoxy Resin 20-40 Specified Complex Compound 2-10