A kind of methyl vinyl silicone rubber and its preparation method and application

Abstract

The present application provides a methyl vinyl silicone rubber having a structure as shown in formula (I): wherein R is selected from methyl and vinyl; R' is selected from x+y=1, x is a number between 0.9-0.999, y is a number between 0.001-0.1; n is an integer between 5000-10000. The present application also provides a preparation method and application of the above-mentioned methyl vinyl silicone rubber. The methyl vinyl silicone rubber provided by the present invention has uniformly distributed cross-linking sites and has better tensile strength and elongation at break after vulcanization.

Description

Technical Field

[0001] The present invention relates to the field of chemistry, and in particular to methyl vinyl silicone rubber, a preparation method thereof and applications thereof. Background Art

[0002] Silicone rubber is a polymer elastomer that combines the properties of both organic and inorganic compounds, offering outstanding properties such as high and low temperature resistance, weather resistance, and electrical insulation. However, its low mechanical strength, poor abrasion and puncture resistance, solvent resistance, and resistance to hot water vapor limit its high-end applications in the power, communications, automotive, and electromechanical sectors. EPDM rubber has excellent electrical insulation, mechanical strength, and impact resilience, but its weather resistance and high-temperature performance are inferior to silicone rubber. Silicone rubber and EPDM rubber are mixed and blended to create a combined rubber. By leveraging their strengths and compensating for their weaknesses, optimized performance is achieved, resulting in a combined rubber with overall performance superior to that of either rubber alone.

[0003] The preparation of high-performance blends requires not only good compatibility to ensure uniform dispersion of the two components, but also matching the vulcanization rates of the two components to achieve synchronous vulcanization, thereby improving the interfacial interaction and system stability. Both EPDM rubber and silicone rubber contain unsaturated double bonds and can be vulcanized with peroxides. However, the unsaturated double bonds in EPDM are less active, resulting in a slower vulcanization rate. A Chinese patent application, published with application number CN 102775686 A, increases the vulcanization rate of EPDM rubber by adding diphenylmethane bismaleimide, bringing the vulcanization rates of the two closer, but a significant gap still exists between the two. Summary of the Invention

[0004] The present invention aims to solve the problem that, during the preparation of silicone rubber / EPDM rubber blends, the silicone rubber vulcanizes at a fast speed, the two components cannot be co-vulcanized, and the mechanical properties of the blend are poor. The invention provides a new methyl vinyl silicone rubber that can be vulcanized slowly.

[0005] According to one aspect of the present application, a methyl vinyl silicone rubber is provided, wherein the methyl vinyl silicone rubber has a structure as shown in formula (I):

[0006]

[0007] Wherein, R is selected from methyl, vinyl; R' is selected from x+y=1, x is a number between 0.9 and 0.999, y is a number between 0.001 and 0.1; and n is an integer between 5000 and 10000.

[0008] According to a second aspect of the present application, there is provided a method for preparing the methyl vinyl silicone rubber described in the first aspect, comprising the following steps: a) subjecting a mixed solution containing methyldichlorosilane and dimethyldichlorosilane to a hydrolysis reaction in the presence of a first catalyst, and after completion of the reaction, subjecting the mixture to separation, rectification, and drying to obtain a hydrogenated siloxane ring body; b) subjecting the hydrogenated siloxane ring body obtained in step a) to a hydrosilylation reaction with a diene in the presence of a platinum-based catalyst to obtain a siloxane ring body containing an unsaturated double bond; and c) adding octamethylcyclotetrasiloxane, a capping agent, and an alkali rubber to the siloxane ring body containing an unsaturated double bond obtained in step b), heating the mixture to 110-120° C. and reacting the mixture for 2-4 hours to obtain a raw silicone rubber.

[0009] Optionally, in the above preparation method, the first catalyst is selected from a combination of one or more of sodium dodecyl sulfonate, sodium octyl sulfonate, and sodium dodecylbenzene sulfonate.

[0010] Optionally, in the above preparation method, the mass ratio of the methyldichlorosilane to the dimethyldichlorosilane is 15-35:65-85; and the reaction temperature of the hydrolysis reaction is 15-35°C.

[0011] Optionally, in the above preparation method, the diene is selected from a combination of one or more of ethylidene norbornene, vinylcyclohexene or dihydromyrcene; and the platinum-based catalyst is selected from at least one of chloroplatinic acid and a Custer catalyst.

[0012] Optionally, in the above preparation method, the end-capping agent is selected from a combination of one or more of hexamethyldisiloxane, decamethyltetrasiloxane or divinyltetramethyldisiloxane.

[0013] Optionally, in the above preparation method, the alkali glue is 1% by mass of tetramethylammonium hydroxide siliconate.

[0014] Optionally, in the above preparation method, the mass ratio of the octamethylcyclotetrasiloxane, the alkali glue, the end-capping agent and the siloxane ring body containing an unsaturated double bond is 97-99:0.3-0.5:0.005-0.05:0.5-20.

[0015] According to the third aspect of the present application, there is provided an application of the methyl vinyl silicone rubber according to the first aspect or the methyl vinyl silicone rubber prepared according to the preparation method of the second aspect in the preparation of silicone rubber / ethylene propylene diene monomer rubber blend.

[0016] Optionally, in the above application, a mixture containing the methyl vinyl silicone rubber and EPDM rubber is mixed and vulcanized to prepare a silicone rubber / EPDM rubber blend.

[0017] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0018] 1) The present invention discloses a novel methyl vinyl silicone rubber having uniformly distributed cross-linking sites and having better tensile strength and elongation at break after vulcanization.

[0019] 2) The novel methyl vinyl silicone rubber disclosed in the present invention has a vulcanization speed matching that of EPDM rubber and can be blended with EPDM rubber to produce a silicone rubber / EPDM rubber blend with excellent comprehensive performance.

[0020] 3) When the silicone rubber with special unsaturated double bonds disclosed in the present invention is used to prepare a silicone rubber and EPDM rubber combined rubber, since the reactivity of the unsaturated double bonds is lower than that of the vinyl group in traditional methyl vinyl silicone rubber, when a peroxide vulcanizing agent is used to initiate cross-linking, the vulcanization rate of the silicone rubber is slowed down, thereby enabling the silicone rubber and EPDM rubber to be simultaneously vulcanized, thereby obtaining a combined rubber with better mechanical properties.

[0021] 4) The novel methyl vinyl silicone rubber disclosed in the present invention uses a siloxane ring containing a single unsaturated double bond to replace the tetramethyltetravinylcyclotetrasiloxane commonly used in the art. The obtained silicone rubber has a more uniform distribution of double bonds in the main chain and has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The stress-strain curves of high temperature vulcanized silicone rubber of Examples 1-3 and Comparative Example 1 are shown;

[0023] Figure 2 The stress-strain curves of silicone rubber / EPDM rubber blends of Application Examples 1-3 and Comparative Example 1 are shown;

[0024] Figure 3 These are internal projection electron micrographs of the silicone rubber / EPDM rubber composite rubber of Application Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] According to one embodiment of the present application, a methyl vinyl silicone rubber is provided. The methyl vinyl silicone rubber has a structure as shown in formula (I):

[0027]

[0028] Wherein, R is selected from methyl, vinyl; R' is selected from x+y=1, x is a number between 0.9 and 0.999, y is a number between 0.001 and 0.1; and n is an integer between 5000 and 10000.

[0029] According to another embodiment of the present application, a method for preparing methyl vinyl silicone rubber is provided, comprising the following steps: a) subjecting a mixed solution containing methyldichlorosilane and dimethyldichlorosilane to a hydrolysis reaction in a hydrochloric acid solution containing 0.5-2% of a surfactant, and after completion of the reaction, separating, rectifying, and drying to obtain a hydrogenated siloxane ring body; wherein the surfactant is selected from a combination of one or more of sodium dodecylsulfonate, sodium octylsulfonate, and sodium dodecylbenzenesulfonate; the mass ratio of methyldichlorosilane to dimethyldichlorosilane is 15-35:65-85; the reaction temperature of the hydrolysis reaction is 15-35°C, specifically, in the mass ratio of methyldichlorosilane to dimethyldichlorosilane, the mass fraction of methyldichlorosilane can be 15, 20, 25, 30, 35, or any value therebetween, and the mass fraction of dimethyldichlorosilane can be 65, 70, 75, 80, 85, or any value therebetween The reaction temperature of the hydrolysis reaction can be 15, 20, 25, 30, 35°C or any value in between these values; b) subjecting the hydrogenated siloxane ring body obtained in step a) and a diene to a hydrosilylation reaction in the presence of a platinum catalyst to obtain a siloxane ring body containing an unsaturated double bond; wherein the diene is selected from a combination of one or more of ethylidene norbornene, vinylcyclohexene or dihydromyrcene. Experimental results show that a 2-10-fold excess of the diene is required to allow the addition reaction to occur entirely on the double bonds of the diene with higher reactivity; the platinum catalyst is selected from at least one of chloroplatinic acid and Custer's catalyst; c) adding octamethylcyclotetrasiloxane, a capping agent and an alkali rubber to the siloxane ring body containing an unsaturated double bond obtained in step b), heating the temperature to 110-120°C for reaction for 2-4 hours, then heating the temperature to 130-140°C and maintaining the temperature for 1 hour to decompose the catalyst alkali rubber, and finally heating the temperature to 170-180°C to remove the low boiling point to obtain a transparent silicone rubber raw rubber. In step c), the reaction temperature can be 110, 112, 114, 116, 118, or 120°C, or any value therebetween, and the reaction time can be 2, 2.5, 3, 3.5, or 4 hours, or any value therebetween. The end-capping agent is selected from a combination of one or more of hexamethyldisiloxane, decamethyltetrasiloxane, or divinyltetramethyldisiloxane. Preferably, the end-capping agent is selected from hexamethyldisiloxane and divinyltetramethyldisiloxane. The alkali glue is 1% by mass of tetramethylammonium hydroxide silicon alkoxide; the mass ratio of octamethylcyclotetrasiloxane, alkali glue, end-capping agent, and siloxane ring containing unsaturated double bonds is 97-99:0.3-0.5:0.005-0.05:0.5-20.In the mass ratio of octamethylcyclotetrasiloxane, alkali glue, end-capping agent and siloxane ring body containing unsaturated double bonds, the mass fraction of octamethylcyclotetrasiloxane can be 97, 98, 99 or any value therebetween, the mass fraction of alkali glue can be 0.3, 0.4, 0.5 or any value therebetween, the mass fraction of end-capping agent can be 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.02, 0.03, 0.04, 0.05 or any value therebetween, and the mass fraction of siloxane ring body containing unsaturated double bonds can be 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or any value therebetween.

[0030] Wherein, in step a), the hydrolysis reaction formula of methyldichlorosilane and dimethyldichlorosilane is as follows:

[0031]

[0032] Among them, in the product DH, m:n is 3 to 6:1.

[0033] According to another embodiment of the present application, there is also provided the use of methyl vinyl silicone rubber in the preparation of silicone rubber / ethylene propylene diene monomer rubber blend.

[0034] In this embodiment, the novel methyl vinyl silicone rubber and EPDM rubber are used as raw materials, reinforcing fillers, additives and vulcanizing agents are added, and silicone rubber / EPDM rubber blended rubber is prepared after mixing and vulcanization. The reinforcing fillers are selected from the common types in this field, such as white carbon black, carbon black, etc. The additives are selected from the common types in this field, such as hydroxy silicone oil, zinc oxide, silane coupling agent KH570, WD-10, etc. The vulcanizing agent is selected from the conventional types in this field, such as organic peroxides, specifically selected from di-tert-butyl peroxide, diisopropyl benzene peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di(tert-butylperoxyisopropyl)benzene, etc.

[0035] The technical solutions of the present invention are described below through specific embodiments.

[0036] Example 1

[0037] (1) 2 parts by mass of sodium octane sulfonate was added to a reaction flask containing 300 parts by mass of a 20 wt% hydrochloric acid aqueous solution, and then a mixed monomer consisting of 80 parts by mass of dimethyldichlorosilane and 20 parts by mass of methyldichlorosilane was added. The mixture was reacted at 25° C. for 1.5 hours. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0038] (2) Take 10 parts by mass of the hydrogenated siloxane ring body obtained in step (1), add 6 parts by mass of vinylcyclohexene, 0.1 parts by mass of 0.25wt% Custer catalyst and 50 parts by mass of toluene, heat to 80°C in a nitrogen environment and react for 24 hours, and distill under reduced pressure to obtain a siloxane ring body containing an unsaturated double bond.

[0039] (3) 1.4 parts by mass of the siloxane ring containing an unsaturated double bond obtained in step (2) was added to 98 parts by mass of octamethylcyclotetrasiloxane that had been dehydrated and dealcoholized, 0.05 parts by mass of divinyltetramethyldisiloxane, and 0.3 parts by mass of an alkali rubber having a mass fraction of 1% of tetramethylammonium hydroxide. The mixture was heated to 115° C. under a nitrogen atmosphere for reaction for 2 h, then heated to 130-140° C. and kept warm for 1 h to decompose the catalyst, and finally heated to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0040] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0041] Example 2

[0042] (1) 2 parts by mass of sodium octane sulfonate was added to a reaction flask containing 300 parts by mass of a 20 wt% hydrochloric acid aqueous solution, and then a mixed monomer consisting of 80 parts by mass of dimethyldichlorosilane and 20 parts by mass of methyldichlorosilane was added. The mixture was reacted at 25° C. for 1.5 hours. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0043] (2) 10 parts by mass of the hydrogenated siloxane ring obtained in step (1) were added with 6 parts by mass of dihydromyrcene, 0.1 parts by mass of 0.25 wt% of Custer catalyst and 50 parts by mass of toluene. The mixture was heated to 80° C. in a nitrogen atmosphere for 24 h, and then distilled under reduced pressure to obtain a siloxane ring containing an unsaturated double bond.

[0044] (3) 1.5 parts by mass of the siloxane ring containing an unsaturated double bond obtained in step (2) was added to 97 parts by mass of octamethylcyclotetrasiloxane that had been dehydrated and dealcoholized, 0.05 parts by mass of divinyltetramethyldisiloxane, and 0.3 parts by mass of an alkali rubber having a mass fraction of 1% of tetramethylammonium hydroxide. The mixture was heated to 115° C. under a nitrogen atmosphere for reaction for 2 h, then heated to 130-140° C. and kept warm for 1 h to decompose the catalyst alkali rubber, and finally heated to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0045] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0046] Example 3

[0047] (1) 2 parts by mass of sodium octane sulfonate was added to a reaction flask containing 300 parts by mass of a 20 wt% hydrochloric acid aqueous solution, and then a mixed monomer consisting of 80 parts by mass of dimethyldichlorosilane and 20 parts by mass of methyldichlorosilane was added. The mixture was reacted at 25° C. for 1.5 hours. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0048] (2) Take 10 parts by mass of the hydrogenated siloxane ring body obtained in step (1), add 15 parts by mass of ethylidene norbornene, 0.1 parts by mass of 0.25wt% of Custer catalyst and 50 parts by mass of toluene, heat to 80°C in a nitrogen environment and react for 24 hours, and distill under reduced pressure to obtain a siloxane ring body containing an unsaturated double bond.

[0049] (3) Take 1 part by mass of the siloxane ring containing an unsaturated double bond obtained in step (2), add 99 parts by mass of octamethylcyclotetrasiloxane that has been dehydrated and dealcoholized, 0.05 parts by mass of divinyltetramethyldisiloxane, and 0.3 parts by mass of alkali rubber with a mass fraction of 1% of tetramethylammonium hydroxide, heat to 115° C. under a nitrogen environment, react for 2 hours, then heat to 130-140° C. and keep warm for 1 hour to decompose the catalyst alkali rubber, and finally heat to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0050] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0051] Example 4

[0052] (1) 2 parts by mass of sodium octane sulfonate was added to a reaction flask containing 300 parts by mass of a 20 wt% hydrochloric acid aqueous solution, and then a mixed monomer consisting of 65 parts by mass of dimethyldichlorosilane and 35 parts by mass of methyldichlorosilane was added. The mixture was reacted at 15° C. for 2 h. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0053] (2) Take 10 parts by mass of the hydrogenated siloxane ring obtained in step (1), add 15 parts by mass of ethylidene norbornene, 0.1 parts by mass of chloroplatinic acid catalyst and 50 parts by mass of toluene, heat to 80°C in a nitrogen environment and react for 24 hours, and distill under reduced pressure to obtain a siloxane ring containing an unsaturated double bond.

[0054] (3) 0.5 parts by mass of the siloxane ring containing an unsaturated double bond obtained in step (2) was added to 0.5 parts by mass of an alkali rubber containing 98 parts of dehydrated and dealcoholized octamethylcyclotetrasiloxane, 0.005 parts by mass of hexamethyldisiloxane, and 1% by mass of tetramethylammonium hydroxide. The mixture was heated to 120° C. under a nitrogen atmosphere for reaction for 2 h, then heated to 130-140° C. and kept warm for 1 h to decompose the catalyst. Finally, the mixture was heated to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0055] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0056] Example 5

[0057] (1) 2 parts by mass of sodium octane sulfonate were added to a reaction flask containing 300 parts by mass of a 20 wt% hydrochloric acid aqueous solution, and then a mixed monomer consisting of 85 parts by mass of dimethyldichlorosilane and 15 parts by mass of methyldichlorosilane was added. The mixture was reacted at 35° C. for 1 hour. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0058] (2) Take 10 parts by mass of the hydrogenated siloxane ring body obtained in step (1), add 6 parts by mass of vinylcyclohexene, 0.1 parts by mass of 0.25wt% Custer catalyst and 50 parts by mass of toluene, heat to 80°C in a nitrogen environment and react for 24 hours, and distill under reduced pressure to obtain a siloxane ring body containing an unsaturated double bond.

[0059] (3) Take 20 parts by mass of the siloxane ring containing an unsaturated double bond obtained in step (2), add 97 parts by mass of octamethylcyclotetrasiloxane that has been dehydrated and dealcoholized, 0.008 parts by mass of decamethyltetrasiloxane, and 0.4 parts by mass of alkali glue with a mass fraction of 1% of tetramethylammonium hydroxide, heat to 110° C. under a nitrogen environment, react for 4 hours, then heat to 130-140° C. and keep warm for 1 hour to decompose the catalyst, and finally heat to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0060] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0061] Example 6

[0062] (1) 2 parts by mass of sodium octane sulfonate was added to a reaction flask containing 300 parts by mass of a 20 wt% aqueous hydrochloric acid solution, and then a mixed monomer consisting of 75 parts by mass of dimethyldichlorosilane and 25 parts by mass of methyldichlorosilane was added. The mixture was reacted at 25° C. for 1.5 hours. After the reaction was completed, the organic phase was washed, distilled, and dried to obtain a hydrogenated siloxane ring.

[0063] (2) 10 parts by mass of the hydrogenated siloxane ring obtained in step (1) were added with 6 parts by mass of dihydromyrcene, 0.1 parts by mass of 0.25 wt% of Custer catalyst and 50 parts by mass of toluene. The mixture was heated to 80° C. in a nitrogen atmosphere for 24 h, and then distilled under reduced pressure to obtain a siloxane ring containing an unsaturated double bond.

[0064] (3) Take 10 parts by mass of the siloxane ring containing an unsaturated double bond obtained in step (2), add 99 parts by mass of octamethylcyclotetrasiloxane that has been dehydrated and dealcoholized, 0.01 parts by mass of divinyltetramethyldisiloxane, and 0.3 parts by mass of alkali glue with a mass fraction of 1% of tetramethylammonium hydroxide, heat to 115° C. under a nitrogen environment, react for 3 hours, then heat to 130-140° C. and keep warm for 1 hour to decompose the catalyst, and finally heat to 180° C. to remove low-boiling products to obtain a clear and transparent silicone rubber raw rubber.

[0065] (4) Take 100 parts by mass of the silicone rubber raw rubber obtained in step (3), add 40 parts of white carbon black, 5 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence to obtain a silicone rubber compound.

[0066] Comparative Example 1

[0067] 100 parts by mass of 60w molecular weight 110-3 methyl vinyl silicone rubber were added, and 40 parts of white carbon black, 5 parts of hydroxy silicone oil and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were added in sequence to obtain a silicone rubber compound.

[0068] Application Example 1

[0069] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 1, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain a silicone rubber / EPDM rubber blend after vulcanization.

[0070] Application Example 2

[0071] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 2, and add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence and mix evenly. After vulcanization, a silicone rubber / EPDM rubber blend is obtained.

[0072] Application Example 3

[0073] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 3, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain a silicone rubber / EPDM rubber blend after vulcanization.

[0074] Application Example 4

[0075] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 4, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain a silicone rubber / EPDM rubber blend after vulcanization.

[0076] Application Example 5

[0077] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 5, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain a silicone rubber / EPDM rubber blend after vulcanization.

[0078] Application Example 6

[0079] Take 30 parts by mass of the raw rubber obtained in step (3) of Example 6, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain a silicone rubber / EPDM rubber blend after vulcanization.

[0080] Comparative Example 2

[0081] Take 30 parts by mass of 60w molecular weight 110-3 methyl vinyl silicone rubber, add 70 parts of Dow 4725P EPDM rubber, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, and 1.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane in sequence, mix evenly, and obtain silicone rubber / EPDM rubber blend after vulcanization.

[0082] The vulcanization characteristics of the rubber were studied at 180°C using a UR-2010SD rubber rotorless vulcanizer. The minimum torque (ML), maximum torque (MH), scorch time (t10) and positive vulcanization time (T90) were obtained. The results are summarized in Table 1.

[0083] Table 1

[0084]

[0085] It can be seen from the data in Table 1 that the scorch time t10 and the positive vulcanization time T90 of the silicone rubber prepared in Examples 1-6 are both greater than t10 and T90 of the silicone rubber in Comparative Example 1, indicating that the vulcanization speed of the silicone rubber prepared in the present invention is significantly slowed down.

[0086] Tensile testing of samples prepared in each of the Examples and Comparative Examples was performed using a Zwick / Roell Z020 universal testing machine at a rate of 50 mm / min. The results are summarized in Table 2. As can be seen from Examples 1-6 and Comparative Example 1, the silicone rubber prepared according to the present invention exhibits improved elongation at break and tensile strength due to a more uniform distribution of crosslinking sites, with Example 6 achieving the highest elongation at break improvement of 97%. As can be seen from Application Examples 1-6 and Comparative Example 2, due to the matching of vulcanization rates, the silicone rubber prepared according to the present invention exhibits significantly reduced phase separation size and improved mechanical properties when used in a silicone rubber / EPDM rubber system.

[0087] Table 2

[0088]

[0089] In summary, the novel methyl vinyl silicone rubber provided by the present invention has uniformly distributed cross-linking sites and exhibits improved tensile strength and elongation at break after vulcanization. Furthermore, the novel methyl vinyl silicone rubber provided by the present invention has a vulcanization rate that matches that of EPDM rubber and can be blended with EPDM rubber to produce a silicone rubber / EPDM rubber blend with excellent overall performance.

[0090] The above embodiments of the present invention focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0091] The foregoing is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A method for preparing methyl vinyl silicone rubber, characterized in that: The methyl vinyl silicone rubber has a structure as shown in formula (I): （Ⅰ） Wherein, R is selected from vinyl; R' is selected from ,or ; x+y=1, x is a number between 0.9-0.999, y is a number between 0.001-0.1; n is an integer between 5000-10000; The preparation method comprises the following steps: a) subjecting a mixed solution containing methyldichlorosilane and dimethyldichlorosilane to a hydrolysis reaction in the presence of a first catalyst, and after completion of the reaction, separating, rectifying, and drying to obtain a hydrogenated siloxane ring; b) subjecting the hydrogenated siloxane ring obtained in step a) and a diene to a hydrosilylation reaction in the presence of a platinum catalyst to obtain a siloxane ring containing an unsaturated double bond, wherein the diene is selected from a combination of one or more of ethylidene norbornene and vinylcyclohexene; c) adding octamethylcyclotetrasiloxane, a capping agent and an alkali rubber to the siloxane ring containing an unsaturated double bond obtained in step b), heating the mixture to 110-120° C. and reacting the mixture for 2-4 hours to obtain a raw silicone rubber.

2. The preparation method according to claim 1, wherein: The first catalyst is selected from a combination of one or more of sodium dodecylsulfonate, sodium octylsulfonate, and sodium dodecylbenzenesulfonate.

3. The preparation method according to claim 1, wherein: The mass ratio of the methyldichlorosilane to the dimethyldichlorosilane is 15-35:65-85; The reaction temperature of the hydrolysis reaction is 15-35°C.

4. The preparation method according to claim 1, wherein: The platinum-based catalyst includes at least one of chloroplatinic acid and a Custer catalyst.

5. The preparation method according to claim 1, characterized in that The end-capping agent is selected from divinyltetramethyldisiloxane.

6. The preparation method according to claim 1, characterized in that The alkali glue is 1% by mass of tetramethylammonium hydroxide silicon alkoxide.

7. The preparation method according to claim 1, characterized in that The mass ratio of the octamethylcyclotetrasiloxane, the alkali glue, the end-capping agent and the siloxane ring body containing an unsaturated double bond is 97-99:0.3-0.5:0.005-0.05:0.5-20.

8. Use of the methyl vinyl silicone rubber prepared by the preparation method according to any one of claims 2 to 7 in the preparation of silicone rubber / ethylene propylene diene monomer rubber blend.

9. The use according to claim 8, characterized in that A mixture containing the methyl vinyl silicone rubber and EPDM rubber is mixed and vulcanized to prepare a silicone rubber / EPDM rubber blend.

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