CN-122011634-A - Fluororubber resistant to high-temperature steam and preparation method thereof

CN122011634ACN 122011634 ACN122011634 ACN 122011634ACN-122011634-A

Abstract

The invention discloses high-temperature steam resistant fluororubber and a preparation method thereof, and belongs to the technical field of fluororubber, wherein the high-temperature steam resistant fluororubber is obtained by mixing rare earth hybridized fluororubber raw rubber on an open mill, adding an auxiliary agent and vulcanizing; the rare earth hybridized fluororubber raw rubber is prepared from fluororubber emulsion and modified rare earth complex solution, wherein the modified rare earth complex solution is prepared by mixing modified methacrylic acid solution and rare earth salt solution, and the preparation process of the modified methacrylic acid solution comprises the steps of adding glycidyl methacrylate into methacrylic acid, adding a catalyst and a polymerization inhibitor to form a mixture A, heating the mixture A for reaction under the protection of nitrogen, and distilling under reduced pressure to obtain modified methacrylic acid. By the method, the fluororubber with excellent mechanical properties, high-temperature aging resistance, high-temperature steam resistance and the like can be prepared.

Inventors

ZHU XIAODONG
WANG GUOLIANG
ZHANG BINGBING
SUN XINGXING

Assignees

常熟三爱富振氟新材料有限公司

Dates

Publication Date: 20260512
Application Date: 20260228

Claims (8)

1. The high-temperature steam resistant fluororubber is characterized in that rare earth hybridized fluororubber raw rubber is mixed on an open mill, and an auxiliary agent is added for vulcanization to obtain the fluororubber; The rare earth hybridized fluororubber raw rubber is prepared from fluororubber emulsion and modified rare earth complex solution, the fluororubber emulsion and the modified rare earth complex solution are uniformly mixed, the total mass of rare earth elements in the modified rare earth complex solution accounts for 0.5-2% of the dry colloid amount of the fluororubber emulsion, then the solid is separated out by adjusting pH and adding a coagulant, and the solid is washed and dried to obtain the fluororubber raw rubber; the modified rare earth complex solution is prepared by mixing a modified methacrylic acid solution and a rare earth salt solution; The preparation process of the modified methacrylic acid solution comprises the steps of adding glycidyl methacrylate into methacrylic acid, adding a catalyst and a polymerization inhibitor to form a mixture A, heating the mixture A to 85-105 ℃ under the protection of nitrogen, continuously stirring and reacting for 4-6 hours under the condition of 300-500 rpm, and carrying out reduced pressure distillation on the product under the conditions of 60-80 ℃ and-0.07-0.10 MPa after the reaction is completed to obtain the modified methacrylic acid.
2. The high-temperature steam resistant fluororubber according to claim 1, wherein the fluororubber emulsion is a vinylidene fluoride-hexafluoropropylene copolymer emulsion or a perfluoroether rubber emulsion with a solid content of 20-30%.
3. The high temperature steam resistant fluororubber according to claim 1, wherein in the preparation of the modified methacrylic acid solution, hydroquinone is used as the polymerization inhibitor, and tetrabutylammonium bromide is used as the catalyst.
4. The high temperature steam resistant fluororubber according to claim 1, wherein the rare earth salt solution is a rare earth nitrate solution, in particular one or more of cerium nitrate, neodymium nitrate or lanthanum nitrate.
5. A process for the preparation of a high temperature steam resistant fluororubber according to any one of claims 1 to 4, characterized in that it comprises in particular the following steps: step 1 Synthesis of modified methacrylic acid Adding glycidyl methacrylate and hydroquinone and tetrabutylammonium bromide into methacrylic acid to form a mixture A, heating the mixture A to 85-105 ℃ under the protection of nitrogen, continuously stirring at 300-500 rpm for reaction for 4-6 hours, and carrying out reduced pressure distillation on the product at 60-80 ℃ and-0.07 to-0.10 MPa after the reaction is finished to obtain modified methacrylic acid; Step 2, preparation of modified rare earth complex solution Dropwise adding a rare earth salt solution into a modified methacrylic acid solution under mechanical stirring, wherein the total mass of rare earth elements in the modified rare earth complex solution accounts for 0.5-2% of the dry colloid weight of the fluororubber emulsion, and continuing stirring reaction to obtain a modified rare earth complex solution after the reaction is completed; the rare earth salt solution adopts one or more of cerium nitrate solution, neodymium nitrate solution or lanthanum nitrate solution; Step 3, preparing rare earth hybridized fluororubber raw rubber Adding the modified rare earth complex solution into fluororubber emulsion with the solid content of 20-30%, after stirring, separating out solids by adjusting pH and adding a coagulant, and washing and drying the solids to obtain rare earth hybridized fluororubber raw rubber; step 4, mixing and vulcanizing Mixing the rare earth hybridized fluororubber raw rubber on an open mill, adding an auxiliary agent, and vulcanizing to obtain the fluororubber resistant to high-temperature steam.
6. The method for preparing high temperature steam resistant fluororubber according to claim 5, wherein the specific process of step 1 is: And adding glycidyl methacrylate into methacrylic acid, wherein the molar ratio of the methacrylic acid to the glycidyl methacrylate is 1:0.5-1, adding tetrabutylammonium bromide accounting for 0.5-2% of the mass of the methacrylic acid as a catalyst and 50-200 ppm of hydroquinone to form a mixture A, and carrying out reduced pressure distillation after the reaction is finished to obtain the modified methacrylic acid.
7. The method for preparing high temperature steam resistant fluororubber according to claim 5, wherein the specific process of step 2 is: Dissolving modified methacrylic acid into ethanol to obtain a modified methacrylic acid solution with the mass concentration of 5-20%; dissolving rare earth nitrate into deionized water to obtain 0.1-0.5 mol/L rare earth salt solution; And (3) dropwise adding the rare earth salt solution into the modified methacrylic acid solution under the mechanical stirring with the rotating speed of 300-600 rpm, so that the molar ratio of rare earth ions in the rare earth salt solution to carboxyl groups in the modified methacrylic acid solution is 1:2-6, and continuously stirring and reacting for 95-145 min at the temperature of 40-60 ℃ after the dropwise adding is finished, thus obtaining the modified rare earth complex solution.
8. The method for preparing high temperature steam resistant fluororubber according to claim 5, wherein the specific process of step 3 is: preheating a fluororubber emulsion with the solid content of 20-30% to 50-70 ℃, adding a modified rare earth complex solution into the fluororubber emulsion under the stirring of the rotating speed of 300-500 rpm, wherein the total mass of rare earth elements in the modified rare earth complex solution accounts for 0.5-2% of the dry colloid content of the fluororubber emulsion, obtaining a mixed solution B after the dripping is finished, and continuously stirring the mixed solution B for 90-120 min at constant temperature; Dropwise adding 5-15% of diluted ammonia water into the mixed solution B after stirring at the rotating speed of 300-400 rpm to enable the pH value of the system to be 8.5-10.0, continuously maintaining stirring for 30-50 minutes, adding 5-15% of calcium chloride solution serving as a coagulant after stirring, continuously stirring for 30-90 minutes to enable all solids to be coprecipitated and separated out, stopping stirring, standing for 1-3 hours, pouring out supernatant liquid to obtain colloidal particles, repeatedly washing the precipitated colloidal particles with hot deionized water at 60-80 ℃ until the conductivity of the washed filtrate is less than 10 mu S/cm, and carrying out forced air drying on the washed colloidal particles at 70-90 ℃ for 24-36 hours to obtain the rare earth hybridized fluororubber raw rubber.

Description

Fluororubber resistant to high-temperature steam and preparation method thereof Technical Field The invention relates to the technical field of fluororubber, in particular to fluororubber resistant to high-temperature steam and a preparation method thereof. Background Fluororubbers, particularly vinylidene fluoride-hexafluoropropylene copolymer and perfluoroether rubber, are widely used for sealing members in the fields of aerospace, automobile industry, petrochemical industry and the like because of their excellent high temperature resistance, oil resistance and chemical medium resistance. In many severe working conditions, long-term exposure to high-temperature steam environments (such as steam pipelines, high-temperature reaction kettles, geothermal equipment and the like) is one of the ultimate tests on the ageing resistance of fluororubber materials. Under the synergistic effect of high-temperature vapor, the material not only faces thermal oxidation aging, but also can undergo hydrolysis reaction, so that a main chain is broken and a crosslinked network is damaged, and further sealing failure is caused. The prior art makes various improvements on fluororubber, for example, china patent CN116410555B discloses a preparation process of high-temperature resistant special fluororubber, 1, 4-di (4-amino-2-trifluoromethyl phenoxy) benzene and dianhydride polymerized monomers are subjected to in-situ polymerization grafting reaction on the surface of graphene through in-situ polymerization reaction to obtain fluorine-containing polyimide grafted graphene, finally, the fluorine-containing polyimide grafted graphene is subjected to blending modification on the fluororubber with polyethylene wax, bisphenol AF, ethylene propylene rubber and the like to obtain high-temperature resistant special fluororubber, the graphene oxide has good compatibility with the fluororubber after being subjected to fluorine-containing polyimide grafting modification, the dispersion effect of graphene nano particles in the fluororubber is improved, meanwhile, the interaction force is formed between fluorine-containing polyimide molecular chains grafted on the surface and the fluororubber, so that the crosslinking site is formed, the mechanical strength and the high-temperature resistance of the fluororubber are improved under the synergistic effect, and the excellent mechanical property is kept at high temperature. However, in practical applications, the following disadvantages remain: 1. In the preparation process of the high-temperature-resistant special fluororubber, all solid/liquid raw materials are mixed on an open mill at one time, so that the dispersion uniformity of the nano filler and the rubber blend with high addition is difficult to ensure, and the performance of the fluororubber is influenced; 2. The improvement of the high-temperature steam resistance and the hydrolytic aging resistance in the fluororubber is still further required to be enhanced. Based on the above, the invention designs a high-temperature steam-resistant fluororubber and a preparation method thereof to solve the problems. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides high-temperature steam-resistant fluororubber and a preparation method thereof. In order to achieve the above purpose, the invention is realized by the following technical scheme: The fluororubber resistant to high-temperature steam is prepared by mixing rare earth hybridized fluororubber raw rubber on an open mill, adding an auxiliary agent and vulcanizing; The rare earth hybridized fluororubber raw rubber is prepared from fluororubber emulsion and modified rare earth complex solution, the fluororubber emulsion and the modified rare earth complex solution are uniformly mixed, the total mass of rare earth elements in the modified rare earth complex solution accounts for 0.5-2% of the dry colloid amount of the fluororubber emulsion, then the solid is separated out by adjusting pH and adding a coagulant, and the solid is washed and dried to obtain the fluororubber raw rubber; the modified rare earth complex solution is prepared by mixing a modified methacrylic acid solution and a rare earth salt solution; The preparation process of the modified methacrylic acid solution comprises the steps of adding glycidyl methacrylate into methacrylic acid, adding a catalyst and a polymerization inhibitor to form a mixture A, heating the mixture A to 85-105 ℃ under the protection of nitrogen, continuously stirring and reacting for 4-6 hours under the condition of 300-500 rpm, and carrying out reduced pressure distillation on the product under the conditions of 60-80 ℃ and-0.07-0.10 MPa after the reaction is completed to obtain the modified methacrylic acid. Furthermore, the fluororubber emulsion adopts vinylidene fluoride-hexafluoropropylene copolymer emulsion or perfluoroether rubber emulsion with the solid content of 20-30%. Furthermore, in the preparat