Preparation method for perfluoroelastomer product having non-stick surface

Abstract

The present invention relates to the technical field of layered products, and in particular to a preparation method for a perfluoroelastomer product having a non-stick surface. The method comprises the following steps: S1, preparation of a perfluoroelastomer product: mixing raw perfluoroelastomer with a filler or a vulcanizing agent to obtain a rubber compound; and vulcanizing the rubber compound to obtain a perfluoroelastomer product; S2, surface treatment: carrying out surface roughening and grease removal treatment on the perfluoroelastomer product; S3, one-step surface treatment: spraying or impregnating a coating a on the surface of the perfluoroelastomer product, and heating to obtain a perfluoroelastomer product having undergone the surface treatment; and S4, two-step surface treatment: spraying or impregnating the non-stick coating a on the surface of the perfluoroelastomer product having undergone the surface treatment, and heating to obtain a perfluoroelastomer product having a non-stick surface. By means of the surface treatment method defined in the present invention, the problem of surface stickiness of the perfluoroelastomer product can be solved, and a surface coating layer does not fall off under the action of an external force.

Description

A method for preparing a non-sticky perfluororubber product Technical Field

[0001] The invention relates to the technical field of layered products, and in particular to a method for preparing a perfluororubber product with a non-sticky surface. Background Art

[0002] Perfluororubber products have the characteristics of high cleanliness, heat resistance, chemical resistance, plasma resistance, etc., and are also used in semiconductor and liquid crystal manufacturing equipment. However, perfluororubber products often adhere to the surface of metal, silicon wafers and other materials in contact with them, making them impossible to tear off. This affects the normal operation of semiconductor and liquid crystal manufacturing equipment in positions where switching operations are frequently performed. When mechanical force is used for tearing, it will cause damage to products such as silicon wafers, perfluororubber products, and production equipment, thereby reducing production efficiency and product yield, and further affecting the performance of the equipment.

[0003] Currently, methods for treating the surface of perfluororubber products to make them non-sticky include: (1) adding low-melting-point or low-molecular-weight additives; (2) plasma treatment of fluororubber products; (3) coating the surface of fluororubber products with silane coupling agents, reactive silicone resins, or non-crystalline fluoropolymer resins; and (4) blending perfluororesin with perfluororubber raw rubber to provide non-stick properties using the perfluoroplastic-rich areas on the surface of the final product. The above treatment methods have certain problems and need further improvement, including the fact that the addition of additives may cause the release of gas or the introduction of new pollutants, which has a fatal impact on applications requiring high purity. There are also problems with the adhesion between perfluororubber and reactive silicone resin, and the mechanical strength of the silicone resin in the surface treatment layer is not high, and its solvent resistance, oil resistance, and chemical resistance are slightly poor, which affects the application of perfluororubber seals. Furthermore, non-crystalline perfluororesin is very expensive and has low production, so the method of coating with non-crystalline fluoropolymers cannot be used on a large scale. The method of blending and modifying perfluororubber and perfluororesin is relatively easy to implement for fluororubber / fluororesin raw material manufacturers, because it is easier to blend the two types of fluoropolymer materials in their original form when they are just polymerized. However, it is difficult to implement for back-end processing manufacturers.

[0004] Chinese patent application number CN200810034222.X discloses a composition and preparation method for a water-based polyethersulfone non-stick coating that does not contain perfluorooctanoic acid. This coating is used for non-stick coatings on rice cookers and is not intended for surface coatings on fluororubber products. Therefore, providing a method for preparing perfluororubber products with surface non-stick properties is a currently unresolved technical problem.

[0005] Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a method for preparing a perfluororubber product with a non-stick surface, comprising the following steps: S1. preparing the perfluororubber product: mixing a perfluororubber raw rubber with a vulcanizing agent to obtain a rubber mix; and vulcanizing the rubber mix at a high temperature to obtain the perfluororubber product;

[0007] S2. Surface treatment: roughening and degreasing the surface of perfluoroelastomer products;

[0008] S3 step surface treatment: FEP emulsion, aqueous dispersion of polyethersulfone and SiO2 are uniformly mixed to obtain a coating sprayed or dipped on the surface of the perfluoroelastomer product, and the surface is heated to obtain a pre-treated perfluoroelastomer product;

[0009] S4 two-step surface treatment: spraying or dipping the surface of the perfluoroelastomer product in a pre-treated non-stick coating and heating, and heating to obtain a perfluoroelastomer product having a non-stick surface;

[0010] After the surface of the perfluororubber product is subjected to roughening treatment in S2, the surface roughness Ra of the perfluororubber product is greater than 5 μm;

[0011] The heating temperature in S4 is set to be lower than 360°C.

[0012] Furthermore, in S2, the surface of the perfluororubber product is roughened by sandblasting, coarse grinding, water grinding or the like, residual particles on the surface are brushed off, and degreasing is performed by using an organic solvent.

[0013] Furthermore, in S2, acetone is used to degrease the surface of the perfluororubber product.

[0014] In order to improve the problem of surface stickiness of perfluororubber products, the applicant accidentally discovered in the experiment that by roughening and degreasing the surface of the perfluororubber products and then performing a two-step surface treatment, especially when the surface roughness Ra of the perfluororubber products after treatment is greater than 5μm, the bonding strength between the surface of the perfluororubber products and the coating can be improved, and the problem of surface coating falling off will not occur under the action of external force, especially when external force is applied in high-temperature water, the surface coating of the perfluororubber products will not fall off, and no particles will fall off. The surface coating has high fastness and improves the permanent service life of the perfluororubber products. In addition, the perfluororubber products have good surface non-stick effect during use, especially when they come into contact with the surfaces of materials such as metals and silicon wafers under pressure, they are easy to tear off, and will not cause damage to products such as silicon wafers, perfluororubber products, and production equipment, thereby improving production efficiency and product yield.

[0015] Preferably, the high temperature vulcanization in S1 is a vulcanization process using one-shot molding vulcanization and two-shot vulcanization.

[0016] Furthermore, the mixed rubber is placed at 160-180° C. and heated for 10-20 minutes while maintaining a pressure of 5 MPa for primary compression vulcanization to obtain vulcanized rubber a; and the vulcanized rubber a is placed at 280-300° C. and heated for at least 20 hours for secondary vulcanization to obtain a perfluororubber product.

[0017] Furthermore, the mixed rubber is heated at 170° C. for 15 minutes while maintaining a pressure of 5 MPa for primary compression vulcanization to obtain vulcanized rubber a; and the vulcanized rubber a is heated at 290° C. for at least 20 hours for secondary vulcanization to obtain a perfluororubber product.

[0018] Preferably, the perfluororubber used in S1 may contain 45-80 mol% of tetrafluoroethylene monomer units, 15-55 mol% of perfluoroether monomer units, and 0.1-5 mol% of perfluororubber cross-linking point monomer units.

[0019] Preferably, the cross-linking point monomer unit of the perfluororubber contains one or a combination of functional groups such as CX (X is iodine or bromine), nitrile, carboxyl or alkoxycarbonyl.

[0020] Preferably, the filler comprises an organic filler or an inorganic filler.

[0021] Furthermore, the filler includes one or both of carbon black and silicon dioxide.

[0022] Preferably, the vulcanizing agent comprises one or more combinations of organometallic compounds, amino-containing organic compounds or functionalized derivatives thereof.

[0023] Furthermore, the vulcanizing agent is a bisaminophenol vulcanizing agent.

[0024] Preferably, the raw materials for preparing the perfluororubber product in S1 further include a vulcanization accelerator.

[0025] Preferably, the vulcanization accelerator includes one or more combinations of multifunctional maleimide, N,N'-m-phenylene bismaleimide, and triallyl isocyanurate.

[0026] Preferably, the raw materials for preparing the coating a are selected from at least one of fluororesin, fluororubber raw rubber, tackifying composition, and dispersant.

[0027] Preferably, the fluororubber raw rubber may be in the form of granules, powder or liquid dispersion. Depending on the form of the coating material for coating, the powder and dispersion forms are respectively preferred.

[0028] Preferably, the melting point of the fluororesin is 250-350°C.

[0029] Preferably, the fluororesin may be in the form of powder or liquid dispersion.

[0030] Preferably, the fluororesin is selected from one or more of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and ethylene-tetrafluoroethylene copolymer.

[0031] Preferably, the adhesion-promoting composition comprises a thermoplastic resin and a vulcanizing agent.

[0032] Furthermore, the content of the viscosity-increasing component is 0.05 wt%-5 wt%, preferably 0.1 wt%-2 wt%.

[0033] Preferably, the vulcanizing agent is selected from one or more of organic peroxides, inorganic peroxides, aminobenzene, bisaminophenol compounds, oxazole, imidazole, thiazole, and triazine compounds.

[0034] Preferably, the adhesion-promoting composition may further include a vulcanization accelerator; the vulcanization accelerator is selected from one or more of multifunctional maleimide PAPI, N,N'-m-phenylene bismaleimide, and triallyl isocyanurate.

[0035] Preferably, the dispersant is selected from at least one of water, an organic solvent, a surfactant, and a modifying additive.

[0036] During the experiment, the inventors found that by using a dispersant, the raw material components can be combined to form a uniformly dispersed liquid composition, and the viscosity, solid content and surface tension of the liquid composition can be further adjusted, and the coating a can be further uniformly dispersed on the surface of the perfluororubber product and can be uniformly adhered to the surface of the perfluororubber product, which is beneficial for the coating a to form a thin film layer with uniform thickness and good adhesion during curing.

[0037] Furthermore, the heat deformation temperature of the thermoplastic resin is greater than 200°C.

[0038] Furthermore, the thermoplastic resin includes one or more combinations of amide groups, imide groups, sulfide groups, sulfone groups, ether groups, and phenylene groups.

[0039] Furthermore, the thermoplastic resin is selected from one or more of polyamide-imide, polyphenylene sulfide, polyethersulfone, and liquid crystal polymer.

[0040] Furthermore, the thermoplastic resin is one or both of polyethersulfone and polyamideimide.

[0041] Furthermore, the fluororesin in the coating a is selected from one or more combinations of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and ethylene-tetrafluoroethylene copolymer.

[0042] Preferably, the fluororubber raw rubber may contain nitrile groups.

[0043] As a preferred example, the raw materials available for the fluororubber raw rubber include FFKM1 and FFKM2.

[0044] The FFKM1 is a nitrile-containing perfluoroelastomer, which was purchased from 3M Company in the United States and has a model number of PFE-131TZ.

[0045] The FFKM2 is a heat-resistant perfluoroelastomer, and its manufacturer and model are Solvay (USA), and its model is PFR 95.

[0046] Preferably, the raw material for preparing the non-stick coating a includes a fluororesin with a melting point of 250-350°C.

[0047] Preferably, the non-stick coating a is in powder or emulsion form.

[0048] Preferably, the fluororesin is selected from one or more of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and ethylene-tetrafluoroethylene copolymer.

[0049] In one embodiment, examples of fluororesins include Mitsui Chemours MJ-102 from Japan, PFA powder with a particle size of about 5-50 μm, and Shanghai Sanaifu FR463 FEP emulsion.

[0050] The PFA is a tetrafluoroethylene-perfluoroalkyl ether copolymer.

[0051] The FEP is a tetrafluoroethylene hexafluoropropylene copolymer.

[0052] Preferably, the heating temperature in S4 is 10-60° C. higher than the melting point of the resin material contained in the non-stick coating a.

[0053] Furthermore, the heating temperature in S4 is set to be 20-50° C. higher than the melting point of the non-stick coating material and is controlled to be lower than the temperature at which the fluororubber material begins to degrade.

[0054] In order to improve the bonding strength between the coatings after two-step surface treatment of perfluororubber products, the applicant creatively discovered in the experiment that when performing a one-step surface treatment, coating a is used for one-step surface treatment, and the raw materials for preparing coating a include fluororesin, fluororubber raw rubber, tackifying composition, and dispersant, and the resin content is 30-95wt%, the fluororubber content is 0-40wt%, the thermoplastic resin is 0-5wt%, and the dispersant is the remainder, and polyethersulfone or polyamideimide with a heat deformation temperature greater than 200°C is used as the thermoplastic resin to bond the perfluororubber. The rubber product undergoes a one-step surface treatment, which is then dried by heating above the melting point of the fluororesin and the vulcanization temperature of the fluororubber. This forms an intermediate bonding layer on the outer layer of the perfluororubber product. The two-step surface treatment is performed using a powdered or emulsion fluororesin with a melting point of 250-350°C. When the heating temperature is set below 360°C, the bonding strength between the coatings after the two-step surface treatment of the perfluororubber product can be improved, preventing the coating from peeling off at high temperatures. Furthermore, the yellowing problem of perfluororubber products during high-temperature treatment can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is an O-ring shape diagram.

[0056] FIG2 is a diagram showing the peeling state of the surface treatment layer of the non-sticky perfluororubber product prepared in Example 2.

[0057] FIG3 is a diagram showing the yellowing state of the substrate of the non-sticky perfluororubber product prepared in Example 5. Beneficial effects

[0058] 1. The surface treatment method defined in the present invention can improve the problem of surface stickiness of perfluororubber products, and the surface coating will not fall off under the action of external force, thereby achieving a permanent sealing effect.

[0059] 2. By adopting the surface treatment method defined in the present invention, when the perfluororubber product is subjected to external force in high-temperature water, the surface coating of the perfluororubber product will not fall off, no particles will fall off, and the surface coating has high fastness.

[0060] 3. By adopting the surface treatment method defined in the present invention, the service life of the perfluororubber product is increased.

[0061] 4. By adopting the surface treatment method defined in the present invention, the surface of the perfluororubber product is made non-sticky during use, especially when it comes into contact with the surface of materials such as metal and silicon wafers under pressure, it is easy to tear off without causing damage to products such as silicon wafers, perfluororubber products, and production equipment, thereby improving production efficiency and product yield.

[0062] 5. By adopting the surface treatment method defined in the present invention, the bonding strength between the coating layers of the perfluororubber product after the two-step surface treatment is improved. DETAILED DESCRIPTION

[0063] Example 1

[0064] A method for preparing a perfluororubber product with a non-stick surface comprises the following steps:

[0065] S1. Preparation of perfluororubber products: 1 g of bisaminophenol curing agent was mixed with 100 g of nitrile-containing perfluororubber raw rubber on an open mill to obtain a rubber mix; the rubber mix was heated at 170°C for 15 min while maintaining a pressure of 5 MPa for a primary compression vulcanization to obtain a vulcanized rubber a; the vulcanized rubber a was heated at 290°C for 20 h for a secondary vulcanization to obtain a perfluororubber product;

[0066] S2. Surface treatment: The surface of the perfluoroelastomer product is roughened by sandblasting, coarse grinding, water grinding, etc., and residual particles are brushed off and degreased with acetone. After the surface treatment in step S2, the surface roughness Ra of the perfluoroelastomer product is greater than 5μm;

[0067] S3. One-step surface treatment: 100 g of PFA powder, 20 g of FFKM1 rubber powder, and 0.3 g of a bisaminophenol curing agent were mixed to obtain a coating a. The coating a was sprayed onto the surface of the perfluororubber product by electrostatic spraying, and the perfluororubber product was heated to 320 ° C at a heating rate of 2 ° C / min and maintained at this temperature for 15 min to obtain a surface pretreated perfluororubber product;

[0068] S4. Two-step surface treatment: PFA powder is coated on the surface of the pretreated perfluororubber product by electrostatic spraying, and the temperature is increased to 330°C at a heating rate of 2°C / min and maintained at 330°C for 10 minutes to obtain a perfluororubber product with a non-stick surface.

[0069] The nitrile-containing perfluoroelastomer in S1 was purchased from FFKM1 of 3M Company of the United States, model number PFE-131TZ.

[0070] The bisaminophenol curing agent in S1 is 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, with a CAS number of 83558-87-6.

[0071] In the surface treatment step S3, the spraying amount of coating a is 100g / m 2 .

[0072] The PFA is a tetrafluoroethylene-perfluoroalkyl ether copolymer.

[0073] The PFA powder used in S3 was purchased from Mitsui Chemours of Japan, model number MJ-102, with a particle size of about 5-50 μm.

[0074] The bisaminophenol vulcanizing agent in S3 is 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, with a CAS number of 83558-87-6.

[0075] In the two-step surface treatment process of S4, the amount of PFA powder sprayed was 100g / m 2 .

[0076] The PFA powder used in S4 was purchased from Mitsui Chemours of Japan, model number is MJ-102, and the particle size is about 5-50 μm.

[0077] Example 2

[0078] A method for preparing a perfluororubber product with a non-stick surface comprises the following steps:

[0079] S1. Preparation of perfluororubber products: 100 g of perfluororubber raw rubber, 20 g of carbon black, 10 g of silica, and 3 g of a vulcanizing agent were mixed on an open mill to obtain a rubber mix; the rubber mix was heated at 170°C for 15 min while maintaining a pressure of 5 MPa for a primary compression vulcanization to obtain a vulcanized rubber a; the vulcanized rubber a was heated at 290°C for 20 h for a secondary vulcanization to obtain a perfluororubber product;

[0080] S2. Surface treatment: The surface of the perfluoroelastomer product is roughened by sandblasting, coarse grinding, water grinding, etc., and residual particles are brushed off and degreased with acetone. After the surface treatment in step S2, the surface roughness Ra of the perfluoroelastomer product is greater than 5μm;

[0081] S3. One-step surface treatment: 100 g of FEP emulsion, 20 g of perfluoroelastomer raw rubber dispersion, 1 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 3 g of triallyl isocyanurate, 10 g of silica, and 30 g of an organic solvent were mixed uniformly using a homogenizer to obtain a coating a, which was sprayed onto the surface of the perfluoroelastomer product and heated to 280 ° C and maintained for 10 min to obtain a surface-pretreated perfluoroelastomer product;

[0082] S4. Two-step surface treatment: FEP emulsion is sprayed on the surface of the pretreated perfluororubber product and heated at 290°C for 10 minutes to obtain a perfluororubber product with a non-stick surface.

[0083] The perfluororubber raw rubber used in S1 is heat-resistant perfluororubber, and the heat-resistant perfluororubber is purchased from Solvay of the United States, and the model is PFR 95.

[0084] The carbon black used in S1 was purchased from Cabot Corporation of the United States, model number N330.

[0085] The silicon dioxide used in S1 is purchased from Evonik

[0086] The sulfiding agent used in S1 is 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane, with a CAS number of 78-63-7.

[0087] The FEP is a tetrafluoroethylene hexafluoropropylene copolymer.

[0088] The FEP emulsion used in S3 was purchased from Shanghai San Ai Fu, with the model number being FR463.

[0089] The dispersion of the perfluororubber raw rubber in S3 contains 30 wt % of the perfluororubber raw rubber and 70 wt % of an aqueous solution containing a fluorine-containing surfactant.

[0090] The mass ratio of the fluorinated surfactant to water in the aqueous solution of the fluorinated surfactant is 0.5:100.

[0091] The fluorinated surfactant can be purchased from Jinan Qifu New Material Technology Co., Ltd., model number perfluorohexylamine oxide CF386N.

[0092] The perfluoroelastomer raw rubber was purchased from Solvay (USA), and the model was PFR 95.

[0093] The organic solvents used in S3 are butanol and ethyl acetate; the weight of the butanol and ethyl acetate is

[0094] The ratio is 1:1.

[0095] The FEP emulsion used in S4 was purchased from Shanghai San Ai Fu, with the model number being FR463.

[0096] In the surface treatment step S3, the spraying amount of coating a is 100g / m 2 .

[0097] During the two-step surface treatment process in S4, the amount of FEP emulsion sprayed was 100g / m 2 .

[0098] Example 3

[0099] A method for preparing a perfluororubber product with a non-stick surface comprises the following steps:

[0100] S1. Preparation of perfluororubber products: 1 g of bisaminophenol curing agent was mixed with 100 g of nitrile-containing perfluororubber raw rubber on an open mill to obtain a rubber mix; the rubber mix was heated at 170°C for 15 min while maintaining a pressure of 5 MPa for a primary compression vulcanization to obtain a vulcanized rubber a; the vulcanized rubber a was heated at 290°C for 20 h for a secondary vulcanization to obtain a perfluororubber product;

[0101] S2. Surface treatment: The surface of the perfluoroelastomer product is roughened by sandblasting, coarse grinding, water grinding, etc., and residual particles are brushed off and degreased with acetone. After the surface treatment in step S2, the surface roughness Ra of the perfluoroelastomer product is greater than 5μm;

[0102] S3 one-step surface treatment: 100g of FEP emulsion, 5g of aqueous dispersion of polyethersulfone and 10gSiO2 were mixed to obtain a coating, the coating a was sprayed on the surface of the perfluoroelastomer product, heated to 280 ° C and maintained for 10min to obtain a surface pretreated perfluoroelastomer product;

[0103] S4. Two-step surface treatment: spray FEP emulsion on the surface of the pretreated perfluororubber product and heat it at 300°C for 10 minutes to obtain a perfluororubber product with a non-stick surface.

[0104] The nitrile-containing perfluoroelastomer in S1 was purchased from FFKM1 of 3M Company of the United States, model number PFE-131TZ.

[0105] The bisaminophenol curing agent in S1 is 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, with a CAS number of 83558-87-6.

[0106] The FEP is a tetrafluoroethylene hexafluoropropylene copolymer.

[0107] The FEP emulsion used in S3 was purchased from Shanghai San Ai Fu, with the model number being FR463.

[0108] The aqueous dispersion of polyethersulfone in S3 was purchased from Quark WP-421.

[0109] The manufacturer and model of SiO2 in S3 is Evonik

[0110] The FEP emulsion used in S4 was purchased from Shanghai San Ai Fu, with the model number being FR463.

[0111] In the surface treatment step S3, the spraying amount of coating a is 100g / m 2 .

[0112] During the two-step surface treatment process in S4, the amount of FEP emulsion sprayed was 100g / m 2 .

[0113] Example 4

[0114] A method for preparing a perfluororubber product with a non-stick surface comprises the following steps:

[0115] S1. Preparation of perfluororubber products: 1 g of bisaminophenol curing agent was mixed with 100 g of nitrile-containing perfluororubber raw rubber on an open mill to obtain a rubber mix; the rubber mix was heated at 170°C for 15 min while maintaining a pressure of 5 MPa for a primary compression vulcanization to obtain a vulcanized rubber a; the vulcanized rubber a was heated at 290°C for 20 h for a secondary vulcanization to obtain a perfluororubber product;

[0116] S2. Surface treatment: The surface of the perfluoroelastomer product is roughened by sandblasting, coarse grinding, water grinding, etc., and residual particles are brushed off and degreased with acetone. After the surface treatment in step S2, the surface roughness Ra of the perfluoroelastomer product is greater than 5μm;

[0117] S3 step surface treatment: 100g of PTFE emulsion, 1g of polyamide-imide aqueous dispersion was mixed to obtain a coating, the coating a was sprayed on the surface of the perfluororubber product, and heated in an oven at 340 ° C for 10min to obtain a surface pretreated perfluororubber product;

[0118] S4. Two-step surface treatment: The surface-pretreated perfluororubber product is immersed in PTFE emulsion for 20 seconds, and then placed in an oven at 340°C for 10 minutes to obtain a perfluororubber product with a non-stick surface.

[0119] The nitrile-containing perfluoroelastomer in S1 was purchased from FFKM1 of 3M Company of the United States, model number PFE-131TZ.

[0120] The bisaminophenol curing agent in S1 is 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, with a CAS number of 83558-87-6.

[0121] The PTFE emulsion used in S3 was purchased from San Ai Fu FR303A.

[0122] The polyamide-imide aqueous dispersion used in S3 was purchased from Quark New Materials SI-308.

[0123] The PTFE emulsion used in S4 was purchased from San Ai Fu FR303A.

[0124] In the surface treatment step S3, the spraying amount of coating a is 100g / m 2 .

[0125] Example 5

[0126] A method for preparing a perfluororubber product with a non-stick surface comprises the following steps:

[0127] S1. Preparation of perfluororubber products: 1 g of bisaminophenol curing agent was mixed with 100 g of nitrile-containing perfluororubber raw rubber on an open mill to obtain a rubber mix; the rubber mix was heated at 170°C for 15 min while maintaining a pressure of 5 MPa for a primary compression vulcanization to obtain a vulcanized rubber a; the vulcanized rubber a was heated at 290°C for 20 h for a secondary vulcanization to obtain a perfluororubber product;

[0128] S2. Surface treatment: The surface of the perfluoroelastomer product is roughened by sandblasting, coarse grinding, water grinding, etc., and residual particles are brushed off and degreased with acetone. After the surface treatment in step S2, the surface roughness Ra of the perfluoroelastomer product is greater than 5μm;

[0129] S3 step surface treatment: 100g of PTFE emulsion, 1g of polyamide-imide aqueous dispersion was mixed to obtain a coating, the coating a was sprayed on the surface of the perfluororubber product, and heated in an oven at 340 ° C for 10min to obtain a surface pretreated perfluororubber product;

[0130] S4. Two-step surface treatment: The surface-pretreated perfluororubber product is immersed in PTFE emulsion for 20 seconds, and then placed in an oven at 360°C for 10 minutes to obtain a perfluororubber product with a non-stick surface.

[0131] The nitrile-containing perfluoroelastomer in S1 was purchased from FFKM1 of 3M Company of the United States, model number PFE-131TZ.

[0132] The bisaminophenol curing agent in S1 is 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, with a CAS number of 83558-87-6.

[0133] The PTFE emulsion used in S3 was purchased from San Ai Fu FR303A.

[0134] The polyamide-imide aqueous dispersion used in S3 was purchased from Quark New Materials SI-308.

[0135] The PTFE emulsion used in S4 was purchased from San Ai Fu FR303A.

[0136] In the surface treatment step S3, the spraying amount of coating a is 100g / m 2 .

[0137] Performance Testing

[0138] 1. Coating fastness test:

[0139] Ten pieces of each of the non-stick perfluororubber articles prepared in Examples 1-5 were placed in 100 g of deionized water, boiled at 100° C. at normal pressure for 1 hour, and then ultrasonically treated at 70° C. for 15 minutes. The deionized water was tested for particulate matter, filtered through a coarse sieve, and dried. The mass of the solid drop material and the solid drop situation were tested, and the maximum and minimum values ​​were removed to take the average value. The test results are shown in Table 1.

[0140] The perfluororubber product is a perfluororubber seal, and its shape and structure are O-rings. The shape of the O-ring is shown in FIG1 .

[0141] As can be seen from FIG2 , the surface treatment layer of the non-sticky perfluororubber product prepared in Example 2 has fallen off.

[0142] 2. Adhesion test:

[0143] According to the coating fastness test results, the perfluororubber products prepared in the examples without falling solid matter were tested. Specifically, 10 pieces of the perfluororubber products with non-sticky surfaces prepared in Examples 1, 3, and 5 were placed in a 304 stainless steel test mold with a roughness of no more than 1.0 μm. The fastening nut was tightened to make the deformation of the perfluororubber product (O-ring) 25%. After being placed at 204°C for 24 hours, the products were taken out and cooled to room temperature. After 3 hours, the minimum tensile force required to pull the O-ring apart from the stainless steel mold was measured using a tensile testing machine at a tensile speed of 1 mm / s. The measured adhesion value of the O-ring under this condition was obtained. The maximum and minimum values ​​were removed and the average value was taken. The test results are shown in Table 1.

[0144] 3. Plasma resistance test

[0145] Using different plasma treatment gases (O2, carbon tetrafluoride CF4, and a blend of O2 and CF4 with a volume ratio of 1:1 (O2 / CF4)), the mass loss rate of the non-sticky perfluororubber products prepared in Examples 1-5 after 60 minutes was tested at a temperature of 100°C and a power of 800W. The vacuum degree set when O2 and a blend of O2 and CF4 with a volume ratio of 1:1 were used as plasma treatment gases for testing was 15mtorr, and the vacuum degree set when CF4 was used as the plasma treatment gas for testing was 40mtorr; the gas flow rate of the plasma treatment gas was set to 80sccm; 10 pieces of non-sticky perfluororubber products prepared in Examples 1-5 were tested, the maximum and minimum values ​​were removed, and the average value was taken. The test results are shown in Table 1.

[0146] Table 1

Claims

1. A method for preparing a perfluororubber product having a non-sticky surface, characterized in that: The following steps are involved: S1. Preparation of perfluororubber products: mixing perfluororubber raw rubber with a vulcanizing agent to obtain a rubber mix; vulcanizing the rubber mix at high temperature to obtain a perfluororubber product; S2. Surface treatment: roughening and degreasing the surface of perfluoro rubber products; S3 one-step surface treatment: The FEP emulsion, the aqueous dispersion of polyethersulfone and SiO2 are uniformly mixed to obtain a coating sprayed or dipped on the surface of the perfluororubber product, and the surface pretreated perfluororubber product is obtained by heating; S4. Two-step surface treatment: spraying or dipping the surface of the pretreated perfluororubber product with a non-stick coating a and heating it to obtain a perfluororubber product having a non-stick surface after heating; After the surface of the perfluororubber product is subjected to rough surface treatment in S2, the surface roughness Ra of the perfluororubber product is greater than 5 μm; The heating temperature in S4 is set to be lower than 360° C.; The raw material for preparing the non-stick coating a is a fluororesin with a melting point of 250-350° C. The non-stick coating a is in a powder or emulsion state; the fluororesin is a tetrafluoroethylene hexafluoropropylene copolymer.

2. The method for preparing a perfluororubber product having a non-sticky surface according to claim 1, characterized in that: The vulcanizing agent includes one or a combination of organic metal compounds and amino-containing organic compounds.

3. The method for preparing a perfluororubber product having a non-sticky surface as claimed in claim 1, characterized in that: The heating temperature in S4 is 10-60° C. higher than the melting point of the resin material contained in the non-stick coating a.

4. The method for preparing a perfluororubber product having a non-sticky surface as claimed in claim 3, characterized in that: The heating temperature in S4 is 20-50° C. higher than the melting point of the resin material contained in the non-stick coating a.

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