Low temperature-resistant fluoroelastomer and preparation method thereof

Abstract

The invention discloses a low temperature-resistant fluoroelastomer and a preparation method thereof. The fluoroelastomer is prepared by thermally kneading and mixing the following components in parts by mass: 100 parts of fluororubber, 0-30 parts of an acid acceptor, 0-35 parts of calcium hydroxide, 0-50 parts of a reinforcing filler, 0-10 parts of a plasticizer, 0.5-5 parts of a vulcanizing agent, 0-5 parts of organic wax, 0.2-2 parts of a promoter, 1-10 parts of (poly) aminosilane, 1-30 parts of carboxyl silicone oil and 1-10 parts of multifunctional adjuvant LCA. The fluoroelastomer provided by the invention is prepared by a simple and low-cost preparation method; according to the preparation method, by adding the carboxyl silicone oil and the active aminosilane, matching with the multifunctional adjuvant LCA and vulcanizing the existing fluororubber composition once or twice, the low-temperature brittle temperature is reduced better (the Tg of the fluoroelastomer can be reduced by about 10 DEG C), so that wider application is achieved.

Description

technical field [0001] The invention relates to a low-temperature-resistant fluorine-containing elastomer and a preparation method thereof, belonging to the technical field of rubber. Background technique [0002] Fluorine rubber refers to a high molecular elastomer with fluorine atoms attached to the carbon atoms of the main chain or side chain of the molecule. In the molecular structure of fluorine rubber, the bond energy of the C-F bond (435-485kJ / mol) is large, and the covalent radius of the fluorine atom (0.064nm) is equivalent to half of the bond length of the C-C bond, and the C-C chain segment is well protected by the fluorine atom Therefore, fluorine rubber has a high degree of chemical stability and thermal stability, and is currently the best medium-resistant property among all elastomers, and can be widely used in aerospace, automobiles, machinery, petrochemicals, etc. [0003] However, one or more copolymers or mixtures containing dibasic or tribasic convention...

AI Technical Summary

Problems solved by technology

[0003] However, one or more copolymers or mixtures containing dibasic or tribasic conventional fluorine-containing ethylenically unsaturated monomers have an outstanding shortcoming in the fluororubber prepared by the existing composition technology: its low temperature performance is too poor (Generally Tg is not lower than -21°C), which is far from meeting the market's requirements for its performance, especially in aviation and aerospace

At present, there are two main ways to solve this problem: one is to use other materials to replace fluorine rubber. It is relatively expensive, and its high temperature stability is not ideal; another method is to add a third or fourth monomer in the synthesis stage to reduce the Tg of fluororubber, thereby improving the problem of insufficient low temperature flexibility, such as in VDF, On the basis of TFE monomer, a new monomer—perfluoromethyl vinyl ether (PMVE) is introduced for copolymerization, but this method requires the addition of a considerable amount of polymerized monomer PMVE, and the amount is usually 20% to 40% (mol fraction). Between, not only the production process is complicated, but also the production cost is very expensive

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