Raw methyl vinyl silicone rubber as well as preparation method and application thereof

Abstract

The invention provides raw methyl vinyl silicone rubber as well as a preparation method and application thereof. The preparation method of the methyl vinyl silicone rubber raw rubber comprises the following steps: mixing octamethylcyclotetrasiloxane, first silicone oil, vinyl double end sockets and an alkali rubber catalyst, and reacting at 90-100 DEG C for 8-10 hours; a preparation method of the first silicone oil comprises the following steps: reacting hydroxyl silicone oil with a methyl vinyl silane monomer at 70-80 DEG C for 4-5 hours, and removing low boiling points to obtain the first silicone oil. Compared with the existing methyl vinyl silicone rubber raw rubber, the silicone rubber material prepared from the raw rubber obtained by the preparation method provided by the invention has the advantages that the physical and mechanical properties of the silicone rubber can be effectively improved after vulcanization under the same mixing condition; the methyl vinyl silicone rubber provided by the invention can be used as raw rubber for preparing high-strength low-compression permanent deformation silicone rubber.

Description

Technical Field

[0001] The invention relates to the technical field of raw silicone rubber synthesis, and more specifically to a methyl vinyl silicone rubber raw rubber and a preparation method and application thereof. Background Art

[0002] Methyl vinyl silicone rubber is an uncured high molar mass linear polysiloxane, whose main chain is composed of Si-O-Si and side chains are composed of methyl and vinyl groups. Heat-cured silicone rubber made from methyl vinyl silicone rubber is widely used in aerospace, electric power, electronics, petrochemical, textile, automobile, medicine, food and daily product processing due to its excellent thermal oxidation stability, weather resistance, high air permeability, electrical insulation, physiological inertness, etc.

[0003] The traditional preparation method of methyl vinyl silicone rubber is to vacuum dehydrate the dimethylsiloxane mixed ring body (DMC), then add vinyl double head (tetramethyl divinyl disiloxane) and vinyl ring body (tetramethyl tetravinyl cyclotetrasiloxane) to carry out ring-opening polymerization under the action of alkali catalyst, and finally remove low molecular volatiles by vacuuming at high temperature to obtain high purity methyl vinyl silicone rubber raw rubber (also called methyl vinyl silicone raw rubber). Among them, vinyl is the active group of this type of methyl vinyl silicone rubber, which quickly cross-links to form an elastomer during the vulcanization process. The existing methyl vinyl silicone rubber has the problems of low strength, brittleness or large deformation after vulcanization, which leads to the situation that silicone rubber products are easy to deform, easy to break, and have poor sealing when used. Summary of the invention

[0004] The first purpose of the present invention is to provide a method for preparing methyl vinyl silicone rubber raw rubber. The methyl vinyl silicone rubber raw rubber obtained by the preparation method is different from the methyl vinyl silicone rubber raw rubber in the prior art or in the traditional sense, and is a modified methyl vinyl silicone rubber raw rubber. Compared with the methyl vinyl silicone rubber in the prior art, the methyl vinyl silicone rubber provided by the present invention is used as the raw rubber and vulcanized under the same mixing conditions. The physical and mechanical properties of the silicone rubber prepared with the methyl vinyl silicone rubber as the raw rubber can be effectively improved, for example, the strength is higher and the deformation rate is lower, thereby effectively reducing the deformation and breakage of the silicone rubber product during use.

[0005] The method for preparing the methyl vinyl silicone rubber provided by the present invention comprises the following steps:

[0006] Octamethylcyclotetrasiloxane, the first silicone oil, a vinyl double-capped end and an alkali-gel catalyst are mixed and reacted at 90° C. to 100° C. for 8 h to 10 h;

[0007] The preparation method of the first silicone oil comprises the following steps: reacting hydroxy silicone oil with methyl vinyl silane monomer at 70° C. to 80° C. for 4 h to 5 h, and removing the low boiling point to obtain the first silicone oil.

[0008] In a preferred embodiment of the present invention, in the preparation method of the first silicone oil, the hydroxy silicone oil is a double-terminal hydroxyl polydimethyl silicone oil with a hydroxyl content of 4.5%-10%. In a specific embodiment of the present invention, the hydroxyl content of the double-terminal hydroxyl polydimethyl silicone oil can be 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10.0%, etc. The applicant of the present invention has experimentally confirmed that the double-terminal hydroxyl polydimethyl silicone oil with a hydroxyl content in the range of 4.5%-10% has good effects in the scheme of the present invention. In the typical embodiment given by the present invention, the present invention is described in detail with a double-terminal hydroxyl polydimethyl silicone oil with a hydroxyl content of 9.0%.

[0009] In a preferred embodiment of the present invention, in the preparation method of the first silicone oil, the methylvinylsilane monomer is methylvinyldichlorosilane, methylvinyldiisopropenyloxysilane, methylvinyldibutylketoximesilane, methylvinyldiacetoxysilane or methylvinylbis(dimethylamino)silane, preferably methylvinyldichlorosilane.

[0010] In a preferred embodiment of the present invention, in order to further improve the performance of methyl vinyl silicone rubber, in the preparation method of the first silicone oil, the molar ratio of hydroxy silicone oil to methyl vinyl silane monomer is (2-4):1.

[0011] In an optional embodiment of the present invention, in the preparation method of the first silicone oil, "removing low boiling points" specifically includes the following steps: distilling at -0.1 MPa and 70-80°C until no bubbles are generated (in a specific embodiment, usually 2 to 3 hours).

[0012] In a preferred embodiment of the present invention, the alkali gel catalyst is sodium hydroxide silicon alkoxide, potassium hydroxide silicon alkoxide or tetramethylammonium hydroxide silicon alkoxide, preferably tetramethylammonium hydroxide silicon alkoxide. In a specific preferred embodiment of the present invention, the mass fraction of sodium hydroxide silicon alkoxide, potassium hydroxide silicon alkoxide and tetramethylammonium hydroxide silicon alkoxide is usually 1%.

[0013] In a preferred embodiment of the present invention, in order to further improve the performance of methyl vinyl silicone rubber, the mass ratio of octamethylcyclotetrasiloxane, the first silicone oil, the vinyl double head and the alkali rubber catalyst is (2000-4260): (30-600): 1: (2-15), preferably (2100-3700): (50-380): 1: (3-10). If the ratio of the first silicone oil is too large, the silicone rubber obtained is too brittle, and if the ratio is too small, the strength of the silicone rubber obtained is too low.

[0014] In a preferred embodiment of the present invention, in the method for preparing methyl vinyl rubber raw rubber, during the reaction of octamethylcyclotetrasiloxane, the first silicone oil, the vinyl double head and the alkali rubber catalyst, nitrogen is introduced to blow out the moisture generated by the reaction.

[0015] In a specific embodiment of the present invention, in the method for preparing methyl vinyl silicone rubber raw rubber, a decomposition step is further included after the reaction is completed. The decomposition step can use different decomposition steps according to the different alkali-gel catalysts used: if the alkali-gel catalyst used is a silicon alkoxide of an inorganic base such as sodium hydroxide silicon alkoxide or potassium hydroxide silicon alkoxide, the decomposition step may include adding an acidic substance to the system after the reaction is completed to make the system neutral; if the alkali-gel catalyst used is a silicon alkoxide of tetramethylammonium hydroxide, the decomposition step may include: after the reaction is completed, the temperature of the reaction system is raised to 140°C to 160°C to decompose the alkali-gel catalyst.

[0016] In a preferred embodiment of the present invention, in the method for preparing methyl vinyl silicone rubber, after the reaction is completed, a catalyst breaking step and a low boiling point removal step are further included. The "low boiling point removal" step includes distillation at -0.09 to -0.1 MPa and 180-200°C until no bubbles are generated.

[0017] Another object of the present invention is to provide methyl vinyl silicone rubber raw rubber obtained by the above preparation method.

[0018] Another object of the present invention is to use the above-mentioned preparation method or the methyl vinyl silicone rubber obtained by the above-mentioned preparation method in the preparation of high-strength and low compression permanent deformation silicone rubber materials.

[0019] The product obtained by the preparation method provided by the present invention is used as the raw rubber of methyl vinyl silicone rubber (if not specifically stated, the methyl vinyl silicone rubber obtained by the present invention may also be referred to as methyl vinyl silicone rubber raw rubber), which can effectively improve the physical comprehensive mechanical properties of silicone rubber after vulcanization (hardness not less than 50 (preferably not less than 65), tensile strength not less than 6.7 MPa (preferably not less than 6.9 MPa, further preferably not less than 8.0 MPa, further preferably not less than 9.0 MPa), tear strength not less than 16 KN / m (preferably not less than 18 KN / m, The methyl vinyl silicone rubber provided by the present invention has a higher strength and a lower deformation rate than the traditional methyl vinyl silicone rubber after vulcanization under the same mixing conditions. The methyl vinyl silicone rubber provided by the present invention can be used for the preparation of high-strength and low-compression permanent deformation silicone rubber. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are further described in detail below in conjunction with the examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. In the present invention, unless otherwise specified, "%" is a mass percentage. In the present invention, parts by weight can be weight units known in the art such as μg, mg, g, kg, or multiples thereof, such as 1 / 10, 1 / 100, 10 times, 100 times, etc. In the present invention, the amount of each substance is determined according to the above ratio, and the total mass parts of the substance are not necessarily 100 parts by weight, and can be less than 100 parts by mass, and can be greater than 100 parts by mass, as long as it is within the above ratio value. In the present invention, the determination standard of vinyl content is GB / T 36691-2018.

[0021] Example 1

[0022] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0023] 1) Preparation of the first silicone oil: 0.5 mol (188.5 g) of hydroxy silicone oil with a hydroxyl content of 9% and 0.25 mol (47.06 g) of methylvinyl diacetoxysilane were mixed in a reaction container, stirred and heated to 80° C., kept warm for 4 hours, and then distilled at -0.1 MPa and 80° C. until no bubbles were generated (small molecules were removed in vacuo), to obtain 204.5 g of the first silicone oil with a vinyl content of 3.31%;

[0024] 2) Polymerization: 3400 parts by weight of D4, 330 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped silicone oil, and 2.8 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were added to a reaction vessel in sequence, heated to 95°C with stirring, and nitrogen was blown in to blow out the water produced by the reaction. The primary product was obtained after reacting for 8 hours;

[0025] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.09 MPa and 200°C for 3 hours until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, i.e., the methyl vinyl silicone rubber raw rubber obtained in this embodiment. The vinyl content was measured to be 0.3% according to GB / T 36691-2018.

[0026] Example 2

[0027] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0028] 1) Preparation of the first silicone oil: 0.5 mol (188.5 g) of hydroxy silicone oil with a hydroxy content of 9% and 0.25 mol (35.25 g) of methylvinyldichlorosilane were mixed in a reaction vessel, stirred and heated to 80° C., kept warm for 4 hours, and then distilled at -0.1 MPa and 80° C. until no bubbles were generated (small molecules were removed in vacuo), to obtain 205 g of the first silicone oil with a vinyl content of 3.28%;

[0029] 2) Polymerization: 2150 parts by weight of D4, 170 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped end cap, and 4.6 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were sequentially added into a reaction vessel, heated to 95°C with stirring for reaction, and nitrogen was blown in to blow out the water produced by the reaction. The primary product was obtained after 8 hours of reaction;

[0030] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.1MPa and 200°C for 3 hours until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.205% according to GB / T36691-2018.

[0031] Example 3

[0032] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0033] 1) Preparation of the first silicone oil: 0.5 mol (188.5 g) of hydroxy silicone oil with a hydroxy content of 9% and 0.25 mol (39.8 g) of di(dimethylamino)methylvinylsilane were mixed in a reaction vessel, stirred and heated to 80° C., kept warm for 4 hours, and then distilled at -0.1 MPa and 80° C. until no bubbles were generated (small molecules were removed in vacuo), to obtain 204.8 g of the first silicone oil with a vinyl content of 3.30%;

[0034] 2) Polymerization: 2800 parts by weight of D4, 80 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped silicone oil, and 8.5 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were added to a reaction vessel in sequence, heated to 95°C with stirring, and reacted while blowing in nitrogen to blow out the water produced by the reaction. The primary product was obtained after reacting for 8 hours;

[0035] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.05MPa and 200°C for 3 hours, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.101% according to GB / T 36691-2018.

[0036] Example 4

[0037] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0038] 1) The preparation method of the first silicone oil is the same as the preparation method of the first silicone oil given in Example 2;

[0039] 2) Polymerization: 3600 parts by weight of D4, 160 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped end cap, and 10 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were sequentially added into a reaction vessel, heated to 100° C. with stirring for reaction, while blowing in nitrogen to blow out the water produced by the reaction, and the primary product was obtained after reacting for 10 hours;

[0040] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.1MPa and 200°C until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.15% in accordance with GB / T36691-2018.

[0041] Example 5

[0042] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0043] 1) The preparation method of the first silicone oil is the same as the preparation method of the first silicone oil given in Example 2;

[0044] 2) Polymerization: 3400 parts by weight of D4, 600 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped silicone oil, and 11 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were added to a reaction vessel in sequence, heated to 100° C. with stirring, and nitrogen was blown in to blow out the water produced by the reaction. The primary product was obtained after reacting for 10 hours;

[0045] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.1MPa and 200°C until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.5% according to GB / T36691-2018.

[0046] Example 6

[0047] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0048] 1) The preparation method of the first silicone oil is the same as the preparation method of the first silicone oil given in Example 2;

[0049] 2) Polymerization: 4260 parts by weight of D4, 30 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped end cap, and 15 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were sequentially added into a reaction vessel, heated to 100° C. with stirring for reaction, while blowing in nitrogen to blow out the water produced by the reaction, and the primary product was obtained after reacting for 10 hours;

[0050] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.1MPa and 200°C until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.03% in accordance with GB / T36691-2018.

[0051] Example 7

[0052] This embodiment provides a methyl vinyl silicone rubber raw rubber, and the preparation method includes the following steps:

[0053] 1) The preparation method of the first silicone oil is the same as the preparation method of the first silicone oil given in Example 2;

[0054] 2) Polymerization: 1840 parts by weight of D4, 580 parts by weight of the first silicone oil, 1 part by weight of a vinyl double-capped end cap, and 2 parts by weight of 1% tetramethylammonium hydroxide silicon alkali glue were sequentially added into a reaction vessel, heated to 100° C. with stirring for reaction, while blowing in nitrogen to blow out the water produced by the reaction, and the primary product was obtained after reacting for 10 hours;

[0055] 3) The primary product was heated to 160°C for 1 hour to decompose tetramethylammonium hydroxide, and then low molecular weight was removed under vacuum at -0.1MPa and 200°C until no bubbles were generated, and finally a colorless, transparent, viscous liquid was obtained, namely, methyl vinyl silicone rubber raw rubber. The vinyl content was measured to be 0.8% in accordance with GB / T36691-2018.

[0056] Experimental example

[0057] Preparation of silicone rubber composite material mixing sample: using a double-roll open mill, add 100 parts by weight of methyl vinyl silicone rubber obtained in the embodiment or comparative example into the roller, add 10 parts by weight of fumed silica after rolling, mix well, add 6 parts by weight of hydroxy silicone oil with a hydroxyl content of 7%, mix well, then add 30 parts by weight of fumed silica, mix well, thinly pass through the sheet, heat at 180°C in hot air circulation for 2h, re-refine again, add 1 part by weight of benzoyl peroxide, mix well, thinly pass through 6 times and sheet, re-refine again and cool to obtain the sample.

[0058] The methyl vinyl silicone rubber raw rubber used in Comparative Examples 1, 2 and 3 is 110-4, 110-3 and 110-1 purchased from Dongjue Silicone Group Co., Ltd., and the vinyl content is 0.3%, 0.2% and 0.1% respectively.

[0059] The Shore hardness of the test sample was tested according to GB / T531.1-2008, the tensile properties of the test sample were tested according to GB / T528-2009, the tear strength of the test sample was tested according to GB / T529-2008, and the compression permanent deformation of the test sample was tested according to GB / T7759.1-2015. The specific physical and mechanical properties of the test sample are shown in Table 1 below:

[0060] Table 1

[0061]

[0062] It can be seen from the test results in Table 1 that the silicone rubber composite material prepared by using methyl vinyl silicone rubber as raw rubber prepared by the method of the present invention has better physical and mechanical properties and can be used for high-strength and low compression permanent deformation silicone rubber materials.

[0063] Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing methyl vinyl silicone rubber raw rubber, characterized in that: The steps include: Octamethylcyclotetrasiloxane, the first silicone oil, a vinyl double-capped end and an alkali-gel catalyst are mixed and reacted at 90° C. to 100° C. for 8 h to 10 h; The preparation method of the first silicone oil comprises the following steps: reacting hydroxy silicone oil with methyl vinyl silane monomer at 70° C. to 80° C. for 4 h to 5 h, and removing the low boiling point to obtain the first silicone oil.

2. The preparation method according to claim 1, characterized in that: The hydroxy silicone oil is a double-terminal hydroxyl polydimethyl silicone oil with a hydroxyl content of 4.5% to 10%.

3. The preparation method according to claim 1 or 2, characterized in that: The methylvinylsilane monomer is methylvinyldichlorosilane, methylvinyldiisopropenyloxysilane, methylvinyldibutylketoximesilane, methylvinyldiacetoxysilane or methylvinylbis(dimethylamino)silane, preferably methylvinyldichlorosilane.

4. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of the hydroxy silicone oil to the methyl vinyl silane monomer is (2-4):

1.

5. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the octamethylcyclotetrasiloxane, the first silicone oil, the vinyl double end cap and the alkali-gel catalyst is (2000-4260):(30-600):1:(2-15).

6. The preparation method according to claim 1 or 2, characterized in that: The alkali gel catalyst is sodium hydroxide siliconate, potassium hydroxide siliconate or tetramethylammonium hydroxide siliconate, preferably tetramethylammonium hydroxide siliconate.

7. The preparation method according to claim 1 or 2, characterized in that: During the reaction process, nitrogen is introduced to blow out the moisture produced by the reaction.

8. The preparation method according to claim 1 or 2, characterized in that: After the reaction is completed, a catalyst breaking step is also included; the catalyst breaking step includes adding an acidic substance to make the system neutral or heating the reaction system to 140°C to 160°C.

9. The methyl vinyl silicone rubber raw rubber obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the preparation method according to any one of claims 1 to 8 or the methyl vinyl silicone rubber according to claim 9 in the preparation of high-strength and low compression permanent deformation silicone rubber materials.

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