Plasma-resistant perfluoroether rubber and preparation method thereof

Abstract

The invention discloses a preparation method of plasma-resistant perfluoroether rubber, which comprises the following steps: S1, carrying out ball milling on boron nitride nanosheets and silica sol, uniformly mixing, drying, adding a polyvinyl alcohol aqueous solution, uniformly mixing, granulating and calcining to obtain an intermediate 1; uniformly mixing the intermediate 1 with a silane coupling agent solution, carrying out grafting reaction, carrying out solid-liquid separation, and drying to obtain three-dimensional boron nitride nanosheet particles; s2, uniformly mixing tetrafluoroethylene, perfluoroalkyl vinyl ether, a vulcanization point monomer, an initiator, a chain transfer agent, the three-dimensional boron nitride nanosheet particles, an emulsifier, a pH regulator and water, carrying out an in-situ emulsion polymerization reaction to obtain a perfluoroether emulsion, and then carrying out condensation, washing and drying to obtain perfluoroether raw rubber; and mixing the perfluoroether raw rubber, octavinyl silsesquioxane and a vulcanizing agent, and performing segmented vulcanization to obtain the plasma-resistant perfluoroether rubber. The invention also discloses the plasma-resistant perfluoroether rubber. The composite material has good high temperature resistance and plasma resistance.

Description

Technical Field

[0001] The invention relates to the technical field of perfluoroether rubber, in particular to a plasma-resistant perfluoroether rubber and a preparation method thereof. Background Art

[0002] Perfluoroether rubber is usually polymerized from a variety of monomers, including tetrafluoroethylene, third vulcanization point monomers and perfluoroalkyl (oxy) vinyl ether. It has excellent chemical corrosion resistance and heat resistance, and is often used as a seal for semiconductor products. Since the semiconductor manufacturing process often requires high temperature and plasma treatment; and the existing perfluoroether rubber's high temperature plasma resistance is still insufficient, after high temperature and plasma treatment, the seals often crack, and then in the later use process, the seals are squeezed or stretched to develop into through cracks, causing the seals to fail. Therefore, it is necessary to improve the high temperature and plasma resistance of perfluoroether rubber. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a plasma-resistant perfluoroether rubber and a preparation method thereof. The present invention cooperates boron nitride nanosheet particles with a three-dimensional structure and octavinyl silsesquioxane to make a three-dimensional thermal conductive structure uniformly distributed in the perfluoroether rubber, which can greatly improve the high temperature resistance and plasma resistance of the perfluoroether rubber.

[0004] The present invention provides a method for preparing plasma-resistant perfluoroether rubber, comprising the following steps: S1, mixing boron nitride nanosheets and silica sol by ball milling, adding polyvinyl alcohol aqueous solution after drying, granulating, calcining, and obtaining intermediate 1; mixing intermediate 1 with silane coupling agent solution, performing grafting reaction, solid-liquid separation, and drying to obtain three-dimensional boron nitride nanosheet particles; S2. Evenly mix tetrafluoroethylene, perfluoroalkyl vinyl ether, vulcanization point monomer, initiator, chain transfer agent, three-dimensional boron nitride nanosheet particles, emulsifier, pH adjuster and water, and carry out in-situ emulsion polymerization to obtain perfluoroether emulsion, which is then condensed, washed and dried to obtain perfluoroether raw rubber; mix perfluoroether raw rubber, octavinyl silsesquioxane and vulcanizing agent, and vulcanize in stages to obtain plasma-resistant perfluoroether rubber.

[0005] In the above S2, the specific preparation steps of the perfluoroether emulsion can be: first, three-dimensional boron nitride nanosheet particles, emulsifier, pH regulator, and water are mixed, and after removing the air, tetrafluoroethylene and perfluoroalkyl vinyl ether are introduced, an initiator is added to react, and then a vulcanization point monomer and a chain transfer agent are added to continue the reaction. Tetrafluoroethylene and perfluoroalkyl vinyl ether are continuously introduced during the entire reaction process until the reaction is completed.

[0006] Preferably, in S1, the weight ratio of boron nitride nanosheets to silica sol is 1:0.2-0.3; the weight ratio of boron nitride nanosheets to polyvinyl alcohol is 1:0.4-0.5.

[0007] In the above S1, SiO 2 The content is 15-20wt%.

[0008] In the above S1, the mass fraction of the polyvinyl alcohol aqueous solution is 6-8wt%.

[0009] In the above S1, the particle size of the intermediate 1 is 100-200 μm.

[0010] Preferably, in S1, the calcination temperature is 750-850°C and the calcination time is 3-4h.

[0011] Preferably, in S1, the silane coupling agent is a mixture of tridecafluorooctyltriethoxysilane and a silane coupling agent containing a carbon-carbon double bond.

[0012] The weight ratio of the above-mentioned tridecafluorooctyltriethoxysilane to the silane coupling agent containing a carbon-carbon double bond is 1:0.8-1.

[0013] The silane coupling agent containing a carbon-carbon double bond may be vinyl trimethoxy silane, vinyl triethoxy silane, γ-methacryloxypropyl trimethoxy silane, or the like.

[0014] Preferably, in S1, the solvent of the silane coupling agent solution is an ethanol aqueous solution with a volume fraction of 20-30%.

[0015] In the above S1, the mass fraction of the silane coupling agent solution is 2-3wt%.

[0016] Preferably, in S1, the grafting reaction temperature is 70-80°C and the time is 2-3h.

[0017] Preferably, in S2, the perfluoroalkyl vinyl ether is at least one of perfluoromethyl vinyl ether and perfluoroethyl vinyl ether; and the vulcanization point monomer is at least one of 4-bromo-3,3,4,4-tetrafluorobutene and 1-bromo-2,2-difluoroethylene.

[0018] Preferably, in S2, the weight ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether is 6-6.5:3.5-4; the weight ratio of tetrafluoroethylene to sulfurization point monomer is 6-6.5:0.2-0.3; the weight ratio of tetrafluoroethylene to three-dimensional boron nitride nanosheet particles is 6-6.5:0.6-0.8.

[0019] In the above S2, the chain transfer agent is at least one of 1,4-diiodoperfluorobutane and 1,6-diiodoperfluorohexane; the initiator is at least one of potassium persulfate and ammonium persulfate; the emulsifier is a combination of perfluoropolyether peroxide and sodium octyl sulfonate; and the pH adjuster is at least one of dipotassium hydrogen phosphate and disodium hydrogen phosphate.

[0020] In the above S2, the weight ratio of tetrafluoroethylene, chain transfer agent and initiator is 6-6.5:0.08-0.12:0.004-0.006.

[0021] In the above S2, the weight ratio of the three-dimensional boron nitride nanosheet particles, the emulsifier, the pH adjuster, and water is 0.6-0.8:0.02-0.04:0.05-0.07:20.

[0022] In the above S2, the temperature of the in-situ emulsion polymerization reaction is 70-80°C.

[0023] Preferably, in S2, the weight ratio of perfluoroether rubber, octavinyl silsesquioxane and vulcanizing agent is 100:5-6:5-6.

[0024] In the above S2, the vulcanizing agent is a mixture of bis-25 vulcanizing agent and triallyl isocyanurate.

[0025] The weight ratio of the above-mentioned bis-25 vulcanizing agent to triallyl isocyanurate is 1:1.

[0026] The above water is all deionized water.

[0027] The invention also provides a plasma-resistant perfluoroether rubber, which is prepared according to the preparation method of the plasma-resistant perfluoroether rubber.

[0028] The present invention ball-mills and mixes boron nitride nanosheets and silica sol, so that nano silicon dioxide is evenly distributed on the surface and between layers of the boron nitride nanosheets; then mixes and granulates with polyvinyl alcohol, and decomposes the polyvinyl alcohol through calcination to obtain an intermediate 1, so that the boron nitride nanosheets in the intermediate 1 form a porous three-dimensional structure, and nano silicon dioxide is evenly distributed on the surface and between layers of the boron nitride nanosheets, and hydroxyl groups on the surface of the nano silicon dioxide are grafted with tridecafluorooctyl triethoxysilane and a silane coupling agent containing a carbon-carbon double bond, so that fluoroalkyl groups and carbon-carbon double bonds are grafted onto the boron nitride nanosheet particles with a porous three-dimensional structure.

[0029] The fluoroalkyl group in the three-dimensional boron nitride nanosheet particles can be mixed with tetrafluoroethylene, perfluoroalkyl vinyl ether, and vulcanization point monomers, and the grafted carbon-carbon double bonds can participate in the in-situ emulsion polymerization reaction, so that the porous three-dimensional structure of the boron nitride nanosheet particles is evenly distributed in the perfluoroether main chain, and the perfluoroether raw rubber can be filled in the porous three-dimensional structure, so that the perfluoroether raw rubber has a continuous three-dimensional thermal conductive network; and then cooperate with octavinyl silsesquioxane, the silsesquioxane itself has a three-dimensional network, and its carbon-carbon double bonds can form a cross-linked network during vulcanization, thereby increasing the density of the three-dimensional thermal conductive network in the rubber, further improving the thermal conductivity, and making the perfluoroether rubber have good high temperature resistance; its evenly distributed three-dimensional network can also improve the barrier performance of the rubber and improve its plasma resistance; and can improve the mechanical properties of the perfluoroether rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a photograph of the plasma-resistant perfluoroether rubber prepared in Example 3 after plasma etching. DETAILED DESCRIPTION

[0031] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0032] Example 1

[0033] A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: S1. Boron nitride nanosheets and silica sol (SiO 2 The boron nitride nanosheets and the polyvinyl alcohol are mixed at a weight ratio of 1:0.4, and the mixture is heated to 850°C and calcined for 3 hours to obtain an intermediate 1 with a particle size of 100 μm; the intermediate 1 is added to a silane coupling agent solution with a mass fraction of 2wt% (the solvent is an ethanol aqueous solution with a volume fraction of 30%, and the silane coupling agent is a mixture of tridecafluorooctyl triethoxysilane and vinyl trimethoxysilane with a weight ratio of 1:0.8) and mixed, and the mixture is heated to 80°C and stirred for 2 hours for grafting reaction, filtered, and dried to obtain three-dimensional boron nitride nanosheet particles; S2, three-dimensional boron nitride nanosheet particles, emulsifier (equal weights of perfluoropolyether peroxide and sodium octyl sulfonate), disodium hydrogen phosphate, and water are mixed in a weight ratio of 0.8:0.04:0.05:20, nitrogen is introduced to remove air, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is compressed into the diaphragm compressor, the pressure is controlled to be 2.5 MPa, potassium persulfate is added to carry out in-situ polymerization at 80°C, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is continuously introduced into the reaction process to keep the pressure constant, and 4- Bromo-3,3,4,4-tetrafluorobutene and 1,4-diiodoperfluorobutane are reacted at 80° C. until a predetermined amount of materials are added, cooled to room temperature, and the reaction is stopped to obtain a perfluoroether emulsion, so that the weight ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, 4-bromo-3,3,4,4-tetrafluorobutene, three-dimensional boron nitride nanosheet particles, 1,4-diiodoperfluorobutane, and potassium persulfate in the perfluoroether is 6:4:0.3:0.8:0.12:0.004; then salting out and condensation are performed, filtered, washed, and dried to obtain a perfluoroether raw rubber; The perfluoroether rubber, octavinyl silsesquioxane and a vulcanizing agent (the vulcanizing agent is equal weights of bis-25 vulcanizing agent and triallyl isocyanurate) are mixed in a weight ratio of 100:5:6, and vulcanized at 170°C for 8 minutes in a first stage and then at 220°C for 20 hours in a second stage to obtain a plasma-resistant perfluoroether rubber.

[0034] Example 2

[0035] A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: S1. Boron nitride nanosheets and silica sol (SiO 2 The boron nitride nanosheets and the polyvinyl alcohol are mixed in a weight ratio of 1:0.5, and the mixture is heated to 750°C and calcined for 4 hours to obtain an intermediate 1 with a particle size of 200 μm; the intermediate 1 is added to a silane coupling agent solution with a mass fraction of 3wt% (the solvent is an ethanol aqueous solution with a volume fraction of 20%, and the silane coupling agent is a mixture of tridecafluorooctyl triethoxysilane and γ-methacryloxypropyl trimethoxysilane in a weight ratio of 1:1), mixed, heated to 70°C and stirred for 3 hours for grafting reaction, filtered, and dried to obtain three-dimensional boron nitride nanosheet particles; S2, three-dimensional boron nitride nanosheet particles, emulsifier (equal weights of perfluoropolyether peroxide and sodium octyl sulfonate), disodium hydrogen phosphate, and water are mixed in a weight ratio of 0.6:0.02:0.07:20, nitrogen is introduced to remove air, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is compressed into the diaphragm compressor, the pressure is controlled to be 2.5 MPa, potassium persulfate is added to carry out in-situ polymerization at 70°C, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is continuously introduced into the reaction process to keep the pressure constant, and 1-bromo-2,2-difluoroethylene and 1,6-diiodoperfluorohexane are reacted at 70° C. until a predetermined amount of materials are added, cooled to room temperature, and the reaction is stopped to obtain a perfluoroether emulsion, so that the weight ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, 1-bromo-2,2-difluoroethylene, three-dimensional boron nitride nanosheet particles, 1,6-diiodoperfluorohexane, and potassium persulfate in the perfluoroether is 6.5:3.5:0.2:0.6:0.08:0.006; then salting out and condensing are performed, filtered, washed, and dried to obtain a perfluoroether raw rubber; The perfluoroether rubber, octavinyl silsesquioxane and a vulcanizing agent (the vulcanizing agent is equal weights of bis-25 vulcanizing agent and triallyl isocyanurate) are mixed in a weight ratio of 100:6:5, and vulcanized at 170°C for 8 minutes in a first stage and then at 220°C for 20 hours in a second stage to obtain a plasma-resistant perfluoroether rubber.

[0036] Example 3

[0037] A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: S1. Boron nitride nanosheets and silica sol (SiO 2 The boron nitride nanosheets and the polyvinyl alcohol are mixed at a weight ratio of 1:0.45, and the temperature is raised to 800°C and calcined for 3.5 hours to obtain an intermediate 1 with a particle size of 150 μm; the intermediate 1 is added to a silane coupling agent solution with a mass fraction of 2.5wt% (the solvent is an ethanol aqueous solution with a volume fraction of 25%, and the silane coupling agent is a mixture of tridecafluorooctyl triethoxysilane and vinyl triethoxysilane with a weight ratio of 1:0.9) and mixed, and the temperature is raised to 75°C and stirred for 2.5 hours for grafting reaction, and filtered and dried to obtain three-dimensional boron nitride nanosheet particles; S2, three-dimensional boron nitride nanosheet particles, emulsifier (equal weights of perfluoropolyether peroxide and sodium octyl sulfonate), disodium hydrogen phosphate, and water are mixed in a weight ratio of 0.7:0.03:0.06:20, nitrogen is introduced to remove air, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is compressed into the mixture by a diaphragm compressor, the pressure is controlled to be 2.5 MPa, potassium persulfate is added to carry out in-situ polymerization at 75°C, tetrafluoroethylene and perfluoromethyl vinyl ether mixed gas is continuously introduced into the mixture during the reaction to keep the pressure constant, and 4-bromo- 3,3,4,4-tetrafluorobutene and 1,6-diiodoperfluorohexane are reacted at 75°C until a predetermined amount of material is added, cooled to room temperature, and the reaction is stopped to obtain a perfluoroether emulsion, so that the weight ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, 4-bromo-3,3,4,4-tetrafluorobutene, three-dimensional boron nitride nanosheet particles, 1,6-diiodoperfluorohexane, and potassium persulfate in the perfluoroether is 6.2:3.8:0.25:0.7:0.1:0.005; then salting out and condensing are performed, filtered, washed, and dried to obtain a perfluoroether raw rubber; The perfluoroether rubber, octavinyl silsesquioxane and a vulcanizing agent (the vulcanizing agent is equal weights of bis-25 vulcanizing agent and triallyl isocyanurate) are mixed in a weight ratio of 100:5.5:5.5, and the mixture is vulcanized at 170°C for 8 minutes in a first stage and then at 220°C for 20 hours in a second stage to obtain a plasma-resistant perfluoroether rubber.

[0038] Comparative Example 1 A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: No three-dimensional boron nitride nanosheet particles were added, and the rest was the same as in Example 3.

[0039] Comparative Example 2 A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: Prepare three-dimensional boron nitride nanosheet particles according to the method of S1 in Example 3; Then, when preparing the perfluoroether rubber according to the method of Example 3, no three-dimensional boron nitride nanosheet particles are added; The obtained perfluoroether rubber, three-dimensional boron nitride nanosheet particles, octavinyl silsesquioxane, and a vulcanizing agent (the vulcanizing agent is equal weights of bis-25 vulcanizing agent and triallyl isocyanurate) are then mixed in a weight ratio of 100:7:5.5:5.5, and vulcanized at 170°C for 8 minutes in a first stage, and then vulcanized at 220°C for 20 hours in a second stage to obtain a plasma-resistant perfluoroether rubber.

[0040] Comparative Example 3 A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: The hydroxylated boron nitride nanosheets were added to a silane coupling agent solution with a mass fraction of 2.5 wt% (the solvent was an ethanol aqueous solution with a volume fraction of 25%, and the silane coupling agent was a mixture of tridecafluorooctyltriethoxysilane and vinyltriethoxysilane in a weight ratio of 1:0.9), and the mixture was heated to 75°C and stirred for 2.5 hours for grafting reaction, filtered, and dried to obtain modified boron nitride nanosheets; The three-dimensional boron nitride nanosheet particles were replaced with modified boron nitride nanosheets, and plasma-resistant perfluoroether rubber was prepared according to the method of S2 in Example 3.

[0041] Comparative Example 4 A method for preparing plasma-resistant perfluoroether rubber comprises the following steps: Octavinylsilsesquioxane was not added, and the other steps were the same as in Example 3.

[0042] The plasma-resistant perfluoroether rubbers prepared in Examples 1-3 and Comparative Examples 1-4 were taken and their properties were tested respectively. The results are shown in Table 1.

[0043] Plasma resistance test: Place the rubber on the reaction table of the plasma etching machine, the heating plate temperature is 250℃, RPS 6000W, and the gas is NF 3 , the flow rate was 3000sccm, and the etching was carried out for 48h; then the weight loss rate, cracks and compression permanent deformation of the rubber were tested. It can be seen from Table 1 that the perfluoroether rubber of the present invention has good high temperature resistance, plasma etching resistance and good mechanical properties.

[0044] Typical pictures such as Figure 1 shown. Figure 1 This is a photograph of the plasma-resistant perfluoroether rubber prepared in Example 3 after plasma etching.

[0045] Depend on Figure 1 It can be seen that after the plasma-resistant perfluoroether rubber prepared in the present invention is etched by plasma, no cracks are generated on the surface, and the plasma-resistant performance is good.

[0046] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a plasma-resistant perfluoroether rubber, characterized in that: The steps include: S1, mixing boron nitride nanosheets and silica sol by ball milling, adding polyvinyl alcohol aqueous solution after drying, granulating, calcining, and obtaining intermediate 1; mixing intermediate 1 with silane coupling agent solution, performing grafting reaction, solid-liquid separation, and drying to obtain three-dimensional boron nitride nanosheet particles; S2. Evenly mix tetrafluoroethylene, perfluoroalkyl vinyl ether, vulcanization point monomer, initiator, chain transfer agent, three-dimensional boron nitride nanosheet particles, emulsifier, pH adjuster and water, and carry out in-situ emulsion polymerization to obtain perfluoroether emulsion, which is then condensed, washed and dried to obtain perfluoroether raw rubber; mix perfluoroether raw rubber, octavinyl silsesquioxane and vulcanizing agent, and vulcanize in stages to obtain plasma-resistant perfluoroether rubber.

2. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S1, the weight ratio of boron nitride nanosheets to silica sol is 1:0.2-0.3; the weight ratio of boron nitride nanosheets to polyvinyl alcohol is 1:0.4-0.

5.

3. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S1, the calcination temperature is 750-850°C and the time is 3-4h.

4. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S1, the silane coupling agent is a mixture of tridecafluorooctyltriethoxysilane and a silane coupling agent containing a carbon-carbon double bond.

5. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S1, the solvent of the silane coupling agent solution is an ethanol aqueous solution with a volume fraction of 20-30%.

6. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S1, the grafting reaction temperature is 70-80°C and the time is 2-3h.

7. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S2, the perfluoroalkyl vinyl ether is at least one of perfluoromethyl vinyl ether and perfluoroethyl vinyl ether; the sulfide point monomer is at least one of 4-bromo-3,3,4,4-tetrafluorobutene and 1-bromo-2,2-difluoroethylene.

8. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S2, the weight ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether is 6-6.5:3.5-4; the weight ratio of tetrafluoroethylene to vulcanization point monomer is 6-6.5:0.2-0.3; the weight ratio of tetrafluoroethylene to three-dimensional boron nitride nanosheet particles is 6-6.5:0.6-0.

8.

9. The method for preparing the plasma-resistant perfluoroether rubber according to claim 1, characterized in that: In S2, the weight ratio of perfluoroether rubber, octavinyl silsesquioxane and vulcanizing agent is 100:5-6:5-6.

10. A plasma-resistant perfluoroether rubber, characterized in that: The method for preparing the plasma-resistant perfluoroether rubber is according to any one of claims 1 to 9.

Images