Fluororubber resistant to synthetic ester lubricating oil and low in compression set

Abstract

The invention discloses fluororubber resistant to synthetic ester lubricating oil and low in compression set. The fluororubber sealing element consists of 100 parts of binary fluororubber, 8-33 parts of an acid acceptor, 10-35 parts of a reinforcing agent, 1-5 parts of a vulcanizing agent and 0.2-2 parts of a vulcanization accelerator. The fluororubber provided by the invention is small in compression set, is in a high temperature and 4050 # synthetic aviation lubricating oil environment for a long time, is small in reduction of tensile strength, elongation at break and compression set, and is long in service life.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and in particular relates to a fluororubber which is resistant to synthetic ester lubricating oil and has low compression permanent deformation. Background Art

[0002] Fluororubber seals usually work in high temperature and various media environments. Fluororubber refers to a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of the main chain or side chain. The introduction of fluorine atoms gives the rubber excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance and atmospheric aging resistance, so fluororubber is usually selected to prepare seals. However, fluororubber has poor tolerance to low molecular ketones, ethers and esters. No. 4050 synthetic aviation lubricant contains ketones, ethers and esters. Therefore, the existing fluororubber seals in China have a large decrease rate of strength and elongation in high temperature and No. 4050 synthetic aviation lubricant environment, and a large constant compression permanent deformation, resulting in poor sealing effect. Summary of the invention

[0003] The object of the present invention is to provide a fluororubber having the characteristics of excellent mechanical properties, resistance to No. 4050 synthetic aviation lubricating oil and small compression permanent deformation.

[0004] The technical solution of the present invention is as follows: the fluororubber seal is composed of the following raw materials in parts by mass: 100 parts of binary fluororubber, 8 to 33 parts of acid absorber, 10 to 35 parts of reinforcing agent, 1 to 5 parts of vulcanizing agent, and 0.2 to 2 parts of vulcanization accelerator.

[0005] According to one embodiment of the present invention, the binary fluororubber is a binary copolymer of vinylidene fluoride and hexafluoropropylene.

[0006] According to one embodiment of the present invention, the acid absorber is one or a combination of two or more of calcium hydroxide, calcium oxide or magnesium oxide.

[0007] According to one embodiment of the present invention, the reinforcing agent is spray carbon black or one of N330 or N774 or N990, or a combination of two or more thereof.

[0008] According to one embodiment of the present invention, the vulcanizing agent is 2,2-bis(4-hydroxyphenyl)-hexafluoropropane.

[0009] According to one embodiment of the present invention, the vulcanization accelerator is benzyltriphenylphosphonium chloride.

[0010] According to one embodiment of the present invention, the fluororubber seal is composed of the following raw materials in parts by mass: 100 parts of binary fluororubber, 18 parts of acid absorber, 22 parts of reinforcing agent, 2.6 parts of vulcanizing agent, and 0.8 parts of vulcanization accelerator.

[0011] In this technical solution, compression set is one of the important parameters of the seal. The present invention selects a copolymer of vinylidene fluoride and hexafluoropropylene with small compression set. Commonly used acid absorbers are mainly metal oxides and certain salts, among which calcium oxide and magnesium oxide are used for heat-resistant rubber materials, and calcium hydroxide is used for low compression set rubber materials. The present invention preferably uses calcium hydroxide and magnesium oxide as acid absorbers. Spray carbon black or a combination of one or more of N330, N774 or N990 is used as a reinforcing agent to make the fluororubber seal have better strength and elongation properties and compression set properties, thereby increasing the service life of the seal. The bisphenol vulcanization system can obtain fluororubber with small compression set. The present invention uses 2,2-bis(4-hydroxyphenyl)-hexafluoropropane as a vulcanizing agent and benzyltriphenylphosphonium chloride as an accelerator.

[0012] The beneficial effects of the present invention are as follows: the fluororubber provided by the present invention has a small compression permanent deformation, and its resistance to 4050 synthetic aviation lubricant is better than that of similar domestic existing products. When it is exposed to high temperature and 4050 synthetic aviation lubricant for a long time, its tensile strength, elongation at break and compression permanent deformation decrease slightly, and its service life is long. DETAILED DESCRIPTION

[0013] The present invention will be described in detail below in conjunction with specific embodiments, but this should not be construed as limiting the scope of the present invention to the following embodiments.

[0014] Comparative Example

[0015] 100 parts of binary fluororubber, 6 parts of magnesium oxide, 6 parts of calcium hydroxide, 20 parts of spray carbon black, 5 parts of N330, 3.0 parts of 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, and 0.6 parts of benzyltriphenylphosphonium chloride.

[0016] Example 1

[0017] 100 parts of binary fluororubber, 10 parts of magnesium oxide, 3 parts of calcium hydroxide, 3 parts of calcium oxide, 12 parts of N990, 8 parts of N330, 2.7 parts of 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, and 0.9 parts of benzyltriphenylphosphonium chloride.

[0018] Example 2

[0019] 100 parts of binary fluororubber, 8 parts of magnesium oxide, 8 parts of calcium oxide, 12 parts of N774, 10 parts of N330, 2.5 parts of 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, and 0.8 parts of benzyltriphenylphosphonium chloride.

[0020] Example 3

[0021] 100 parts of binary fluororubber, 3 parts of magnesium oxide, 9 parts of calcium hydroxide, 25 parts of N7742, 3 parts of 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, and 0.8 parts of benzyltriphenylphosphonium chloride.

[0022] The properties of vulcanized rubber are as follows:

Claims

1. A fluororubber that is resistant to synthetic ester lubricants and has low compression set. Features The following raw materials are used in parts by mass Composition: 100 parts of binary fluororubber, 8-33 parts of acid absorber, 10-35 parts of reinforcing agent, 1-5 parts of vulcanizing agent, 0.2-2 parts of vulcanization accelerator; the binary fluororubber is a binary copolymer of vinylidene fluoride and hexafluoropropylene; the acid absorber is one or a combination of two or more of calcium hydroxide, calcium oxide or magnesium oxide; the reinforcing agent is spray carbon black, or one or a combination of two or more of N330, N774 or N990; the vulcanizing agent is 2,2-bis(4-hydroxyphenyl)-hexafluoropropane; the vulcanization accelerator is benzyltriphenylphosphonium chloride.

2. A fluororubber resistant to synthetic ester lubricating oil and having low compression set according to claim 1, Features The following raw materials are used in parts by mass Composition: 100 parts of binary fluororubber, 18 parts of acid absorber, 22 parts of reinforcing agent, 2.6 parts of vulcanizing agent, and 0.8 parts of vulcanization accelerator.

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