Preparation method of organosilicon cyclic cross-linking agent

Abstract

The invention provides a preparation method of an organosilicone cyclic cross-linking agent, and belongs to the technical field of high polymer materials, the preparation method comprises the following steps: carrying out hydrosilylation reaction on hydrogen-containing silicon resin and cyclic polyolefins as raw materials in a solvent system consisting of a solvent and a viscosity modifier under the action of a catalyst to obtain the organosilicone cyclic cross-linking agent, and after the reaction is completed, removing the solvent to obtain the organic silicon annular cross-linking agent. The cross-linking agent prepared by the preparation method disclosed by the invention has more active hydrogen, meanwhile, the active hydrogen is more concentrated, and more concentrated cross-linking points are provided for the addition type silicone rubber, so that the mechanical properties such as tear strength, tensile strength, elongation at break and the like of the addition type silicone rubber are improved.

Description

Technical Field

[0001] The present invention relates to the preparation of a crosslinking agent, and particularly to a preparation method of an organosilicon crosslinking agent, belonging to the technical field of polymer materials. Background Art

[0002] The addition-cured silicone rubber is a synthetic rubber and belongs to the organosilicon series. This kind of silicone rubber is divided into elastic silicone gel and silicone rubber. The former has lower strength, while the latter has higher strength. The viscosity of the addition-cured silicone rubber stock before vulcanization is lower, which is convenient for pouring. During vulcanization, it does not generate heat, does not release low-molecular by-products, has a small shrinkage rate, and can be deeply vulcanized.

[0003] At present, the crosslinking agents used in addition-cured organosilicon rubbers are mainly organosiloxanes with multifunctionality such as hydrogen-containing silicone oil, vinyl silicone resin, and hydrogen-containing silicone resin, but they cannot meet the requirements of the addition silicone rubber field with some special performance requirements. For example, in order to achieve the high elongation at break, high tear strength and other properties of the simulated silicone rubber, the crosslinking agent needs to have a higher crosslinking density and more concentrated crosslinking sites. Summary of the Invention

[0004] In view of the above problems, the present invention provides a preparation method of an organosilicon cyclic crosslinking agent to meet the performance requirements such as high elongation at break and high tear strength of the addition silicone rubber with some special performance requirements.

[0005] To achieve the above object, the technical solution of the present invention is: a preparation method of an organosilicon cyclic crosslinking agent, which uses a hydrogen-containing silicone resin and a cycloalkadiene as raw materials, and carries out a hydrosilylation reaction in a solvent system composed of a solvent and a viscosity regulator and under the action of a catalyst. After the reaction is completed, the solvent is removed to obtain the organosilicon cyclic crosslinking agent.

[0006] Further, the hydrogen content of the hydrogen-containing silicone resin is 0.3%-0.7%, and the hydrogen-containing silicone resin also contains inert organic groups, and the inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl.

[0007] Further, the cycloalkadiene includes but is not limited to the following types: cyclohex-1,3-diene, cyclohex-1,4-diene, bicycloheptadiene; the cycloalkadiene also contains inert organic groups, and the inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl.

[0008] Further, the ratio of the hydrogen-containing silicone resin to the cycloalkadiene is calculated according to the molar ratio of the hydrogen content of the hydrogen-containing silicone resin to the vinyl content of the cycloalkadiene, and the molar ratio of the hydrogen content to the vinyl content is (5-8):1.

[0009] Further, the catalyst is platinum(0) and catalyzes the hydrosilylation reaction in the following solution state, including: a divinyltetramethyldisiloxane solution containing platinum(0) and an α,ω-divinylpolydimethylsiloxane solution containing platinum(0). The concentration of platinum(0) in both the divinyltetramethyldisiloxane solution containing platinum(0) and the α,ω-divinylpolydimethylsiloxane solution containing platinum(0) is 5000 ppm.

[0010] Further, the viscosity regulator is methyl silicone oil with a viscosity of 40 - 80 mP·s, and the addition amount of the viscosity regulator is 5% - 10% of the total mass of the raw material hydrogen-containing silicone resin and cycloalkene.

[0011] Further, the solvent is an aromatic compound, and the usage ratio of the solvent is 2 - 3 times the total mass of the raw material hydrogen-containing silicone resin and cycloalkene.

[0012] Further, the aromatic compound is toluene or xylene.

[0013] Further, the temperature of the hydrosilylation reaction is 60 - 100 °C, the reaction time is 2 - 3 h, the reaction pressure is normal pressure, and the reaction is carried out under nitrogen protection.

[0014] Further, after the raw material hydrogen-containing silicone resin and cycloalkene are added to the solvent system, the catalyst is added for the hydrosilylation reaction when the temperature of the reaction system rises to 60 - 100 °C; the solvent is removed by distillation, and the temperature of the distillation is 110 - 140 °C.

[0015] The beneficial effects of a preparation method of an organosilicon cyclic crosslinking agent of the present invention are as follows:

[0016] By using a specific solvent, the present invention enables the raw material hydrogen-containing silicone resin and cycloalkene to be uniformly dispersed in the system. Through the hydrosilylation reaction, the hydrogen-containing silicone resin is grafted onto the cyclic olefin. Controlling the excess hydrogen content can make the prepared cyclic crosslinking agent have more active hydrogens and make the active hydrogens more concentrated, providing more and more concentrated crosslinking sites for addition-curable silicone rubber, thereby improving the mechanical properties such as tear strength, tensile strength, and elongation at break of the addition-curable silicone rubber.

[0017] The solvent of the present invention is an aromatic compound, and its main function is to dissolve the hydrogen-containing silicone resin and cycloalkene, so that they are uniformly dispersed in the solvent system, avoiding reaction problems caused by the immiscibility of the hydrogen-containing silicone resin and cycloalkene.

[0018] The viscosity regulator of the present invention is selected as methyl silicone oil with a viscosity of 40-80 mP·s; methyl silicone oil mainly has two functions. One is to reduce the viscosity of the reaction system, make the raw materials and catalysts more evenly dispersed, and improve the uniformity of the reaction. The other is to control the viscosity of the reaction product, the organosilicon cyclic crosslinking agent, so that it is easily dispersed in the addition-type silicone rubber system and improve the processing performance of the silicone rubber. Detailed implementation manners

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar promotions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0020] A preparation method of an organosilicon cyclic crosslinking agent. In a system with a solvent and a viscosity regulator, a hydrogen-containing silicone resin and a cycloalkene are used as raw materials, and a hydrosilylation reaction is carried out under the action of a catalyst. First, a certain proportion of the solvent and the viscosity regulator are added to the reaction system, and the hydrogen-containing silicone resin and the cycloalkene are fully mixed in proportion in the solvent system. During the mixing process, the temperature is gradually raised to the specified temperature range. After the above conditions are completed, a certain proportion of the catalyst is added to the system to start the synthesis reaction. After the reaction is completed, the solvent is removed by distillation to obtain the organosilicon cyclic crosslinking agent.

[0021] Preferably, the hydrogen content of the hydrogen-containing silicone resin is 0.3%-0.7%, and the hydrogen-containing silicone resin also contains inert organic groups. The inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl (the hydrogen-containing silicone resin containing the above inert groups can be, for example, methylhydrogen silicone resin, phenylhydrogen silicone resin or ethylhydrogen silicone resin).

[0022] The cycloalkene includes but is not limited to the following types: cyclohex-1,3-diene, cyclohex-1,4-diene, bicycloheptadiene; the cycloalkene also contains inert organic groups. The inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl (the cycloalkene containing the above inert groups can be, for example, 1-methyl-1,4-cyclohexadiene, 1-ethyl-1,4-cyclohexadiene, 3-phenyl-1,4-cyclohexadiene, 1,5-dimethyl-1,5-cyclooctadiene).

[0023] The ratio of the hydrogen-containing silicone resin to the cycloalkene is calculated according to the molar ratio of the hydrogen content of the hydrogen-containing silicone resin to the vinyl content of the cycloalkene, and the molar ratio of the hydrogen content to the vinyl content is (5-8):1.

[0024] The catalyst is zero-valent platinum, and it catalyzes the hydrosilylation reaction in the following solution state: including a divinyltetramethyldisiloxane solution containing zero-valent platinum and an α,ω-divinylpolydimethylsiloxane solution containing zero-valent platinum. The concentration of zero-valent platinum in both the divinyltetramethyldisiloxane solution containing zero-valent platinum and the α,ω-divinylpolydimethylsiloxane solution containing zero-valent platinum is 5000 ppm.

[0025] The viscosity regulator is methyl silicone oil with a viscosity of 40 - 80 mP·s, and the addition amount of the viscosity regulator is 5% - 10% of the total mass of the raw material hydrogen-containing silicone resin and cycloolefin.

[0026] The solvent is an aromatic compound, and the usage ratio of the solvent is 2 - 3 times the total mass of the raw material hydrogen-containing silicone resin and cycloolefin.

[0027] The aromatic compound is toluene or xylene.

[0028] The temperature of the hydrosilylation reaction is 60 - 100 °C, the reaction time is 2 - 3 h, the reaction pressure is normal pressure, and it is carried out under nitrogen protection.

[0029] After the raw material hydrogen-containing silicone resin and cycloolefin are added to the solvent system, the catalyst is added for the hydrosilylation reaction when the temperature of the reaction system rises to 60 - 100 °C; the solvent is removed by distillation, and the temperature of the distillation is 110 - 140 °C.

[0030] Examples 1 - 4

[0031] The organosilicon cyclic crosslinking agent is prepared according to the above hydrosilylation reaction steps. The viscosity of the product is tested using a rotational viscometer, and the hydrogen content of the product is determined using Fourier transform infrared spectroscopy. The specific material usage amounts and reaction conditions in each example are shown in Table 1 below:

[0032] Table 1 Control of preparation conditions and product indexes of organosilicon cyclic crosslinking agent

[0033]

[0034] Comparative Examples 1 - 2

[0035] Comparative Examples 1 - 2 are based on Example 3 with the usage ratio of the hydrogen-containing silicone resin and cycloolefin changed. In Comparative Example 1, the molar ratio of the hydrogen content in the hydrogen-containing silicone resin to the vinyl group in the cycloolefin is 4:1, and in Comparative Example 3, the molar ratio of the hydrogen content in the hydrogen-containing silicone resin to the vinyl group in the cycloolefin is 9:1. Other conditions are the same as those in Example 3; the viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 1 is 102 mP·s, and the hydrogen content is 0.13%; the viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 2 is 150 mP·s, and the hydrogen content is 0.19%.

[0036] Comparative Example 3-4

[0037] Comparative Example 3-4 was based on Example 3 with the amount of the viscosity regulator changed. In Comparative Example 3, the addition amount of the viscosity regulator was 4% of the total mass of the raw material hydrogen-containing silicone resin and cyclo-polyolefin. In Comparative Example 4, the addition amount of the viscosity regulator was 11% of the total mass of the raw material hydrogen-containing silicone resin and cyclo-polyolefin. The other conditions were the same as those in Example 3. The viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 3 was 458 mP·s, and the hydrogen content was 0.19%. The viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 4 was 145 mP·s, and the hydrogen content was 0.12%.

[0038] Comparative Example 5

[0039] Comparative Example 5 was based on Example 3 with the type of the catalyst changed. In Comparative Example 5, the catalyst was a complex of chloroplatinic acid and tetramethyldivinyldisiloxane. The other conditions were the same as those in Example 3. The viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 5 was 150 mP·s, and the hydrogen content was 0.18%.

[0040] Comparative Example 6

[0041] Comparative Example 6 was based on Example 3 with the type of the solvent changed. In Comparative Example 6, the solvent was cyclohexane. The other conditions were the same as those in Example 3. The viscosity of the organosilicon cyclic crosslinking agent prepared in Comparative Example 5 was 265 mP·s, and the hydrogen content was 0.10%.

[0042] Test Example 1-4

[0043] The organosilicon cyclic crosslinking agents prepared in Examples 1-4 were used to prepare addition-curable organosilicon rubber. According to the established quality in the following table, vinyl silicone oil, terminal hydrogen-containing silicone oil, hydrogen-containing silicone oil, organosilicon cyclic crosslinking agent, and fumed silica were placed in a planetary mixer and mixed, and then gradually heated to 150 °C and stirred for 1 hour, evacuated to -0.08 ± 0.005 Mpa and maintained for 2 h. After cooling, a quantitative catalyst (platinum(0) divinyldimethylsiloxane) was added and mixed for 10 min, and then cured in a tetrafluoro mold into a 2-mm thick sheet. A universal material testing machine was used to measure the tear strength, tensile strength, and elongation at break of the material, and a durometer was used to measure the hardness of the material. The types of raw materials used in the preparation and the product indexes of the obtained addition-curable organosilicon rubber are shown in Table 2:

[0044] Table 2

[0045]

[0046] Comparative Test Example 1-4

[0047] While keeping the ratio of the silane hydrogen functional group to the vinyl functional group unchanged, the organosilicon cyclic crosslinking agent in the above test examples was correspondingly replaced with a hydrogen-containing silicone resin. The amounts of each raw material and the product indexes of the addition-cured organosilicon rubber prepared in Comparative Test Examples 1-4 are shown in Table 3 below:

[0048] Table 3

[0049]

[0050]

[0051] Comparative Test Examples 5-10

[0052] The organosilicon cyclic crosslinking agent prepared in Comparative Examples 1-6 (corresponding to Comparative 5-Comparative 10 in the following table respectively) was applied to prepare an addition-cured organosilicon rubber, and the other conditions were the same as those in Test Example 3. The specific amounts of each raw material and the indexes of the products prepared are shown in Table 4 below:

[0053] Table 4

[0054]

[0055] In summary, it can be seen that the cyclic crosslinking agent prepared by the present invention has more active hydrogens, and at the same time, the active hydrogens are more concentrated, providing more and more concentrated crosslinking sites for the addition-cured silicone rubber, thereby improving the mechanical properties such as tear strength, tensile strength, and elongation at break of the addition-cured silicone rubber.

[0056] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

Claims

1. A preparation method of an organosilicon cyclic crosslinking agent, characterized in that, The preparation method is as follows: using a hydrogen-containing silicone resin and a cyclo-polyolefin as raw materials, performing a hydrosilylation reaction in a solvent system composed of a solvent and a viscosity regulator and under the action of a catalyst, and removing the solvent after the reaction is completed to obtain an organosilicon cyclic crosslinking agent.

2. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The hydrogen content of the hydrogen-containing silicone resin is 0.3%-0.7%, and the hydrogen-containing silicone resin also contains inert organic groups, and the inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl.

3. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The cyclo-polyolefin includes but is not limited to the following types: cyclohex-1,3-diene, cyclohex-1,4-diene, bicycloheptadiene; the cyclo-polyolefin also contains inert organic groups, and the inert organic groups include but are not limited to the following types: methyl, phenyl, ethyl.

4. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The ratio of the hydrogen-containing silicone resin to the cyclo-polyolefin is calculated according to the molar ratio of the hydrogen content of the hydrogen-containing silicone resin to the vinyl content of the cyclo-polyolefin, and the molar ratio of the hydrogen content to the vinyl content is (5-8):

1.

5. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The catalyst is zero-valent platinum, and catalyzes the progress of the hydrosilylation reaction in the following solution states: a divinyltetramethyldisiloxane solution containing zero-valent platinum, an α,ω-divinylpolydimethylsiloxane solution containing zero-valent platinum, and the concentration of zero-valent platinum in the divinyltetramethyldisiloxane solution containing zero-valent platinum and the α,ω-divinylpolydimethylsiloxane solution containing zero-valent platinum is 5000 ppm.

6. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, wherein, The viscosity regulator is a methyl silicone oil with a viscosity of 40-80 mP·s, and the addition amount of the viscosity regulator is 5%-10% of the total mass of the raw material hydrogen-containing silicone resin and cyclo-polyolefin.

7. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The solvent is an aromatic compound, and the usage amount of the solvent is 2-3 times the total mass of the raw material hydrogen-containing silicone resin and cyclo-polyolefin.

8. The preparation method of an organosilicon cyclic crosslinking agent according to claim 7, characterized in that, The aromatic compound is toluene or xylene.

9. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, characterized in that, The temperature of the hydrosilylation reaction is 60-100 °C, the reaction time is 2-3 h, the reaction pressure is normal pressure, and it is carried out under nitrogen protection.

10. The preparation method of an organosilicon cyclic crosslinking agent according to claim 1, wherein After the raw material hydrogen-containing silicone resin and cyclo-polyolefin are added to the solvent system, the catalyst is added for the hydrosilylation reaction when the temperature of the reaction system rises to 60-100 °C; the solvent is removed by distillation, and the distillation temperature is 110-140 °C.

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