Preparation method of three-dimensional silicon resin in non-solvent system

Abstract

The invention discloses a preparation method of three-dimensional silicon resin in a non-solvent system, and belongs to the technical field of preparation of silicon resin. The preparation method of the three-dimensional silicon resin comprises the following steps: preparing a phosphonitrile chloride catalyst; the preparation method comprises the following steps: adding 30-50 parts of tetramethyl orthosilicate or tetraethoxysilane into vinyl silicone oil, and uniformly stirring; adding phosphoric acid into the solution obtained in the step S2, and uniformly stirring; s3, adding the phosphonitrile chloride catalyst prepared in the step S1 into the reaction liquid in the step S3, dropwise adding deionized water, and vacuumizing; dropwise adding 2 to 10 parts of trimethylchlorosilane into the reaction liquid obtained in the step S4; and S6, dropwise adding silazane accounting for 1% of the total mass of the reactant into the reactant obtained in S5 to obtain the three-dimensional silicon resin. By adopting the preparation method of the three-dimensional silicon resin in the non-solvent system, the problem of environmental pollution caused by volatilization of an organic solvent in the existing silicon resin preparation process can be solved, and the preparation safety of the silicon resin is improved. The prepared three-dimensional silicon resin has relatively high impact strength and tensile strength and good toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of silicone resins, and particularly to a method for preparing three-dimensional silicone resins in a non-solvent system. Background Art

[0002] Silicone resins are thermosetting polyorganosiloxanes with a highly cross-linked structure. Due to their special structure, compared with other organic resins, they have excellent heat resistance, cold resistance, weather resistance, electrical insulation, hydrophobicity, anti-sticking and demolding properties, etc. Therefore, they are widely used as insulating paints for high and low temperatures, heat-resistant coatings, weather-resistant coatings, ablative-resistant coatings, and mold plastics for high and low temperatures and electrical insulation.

[0003] Silicone resins are generally prepared from a mixture of organochlorosilanes or organoethoxysilanes through hydrolysis and polycondensation reactions in a mixed solvent. The curing of silicone resins is to transform into a thermosetting resin with a three-dimensional network structure that is insoluble and infusible under the action of heating or a catalyst. Silicone resins generally need to be cured and formed at high temperatures, which limits their scope of use. In the preparation of traditional silicone resins, the volatilization of solvents will cause VOC emissions and safety hazards.

[0004] Silicone resins are usually prepared by hydrolyzing various mixtures of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane or methylphenyldichlorosilane in the presence of an organic solvent such as toluene at a lower temperature to obtain an acidic hydrolyzate. The initial products of hydrolysis are a mixture of cyclic, linear and cross-linked polymers, usually containing a considerable amount of hydroxyl groups. The hydrolyzate is washed with water to remove the acid, and the neutral initial condensate is further polycondensed by thermal oxidation in air or in the presence of a catalyst, and finally a highly cross-linked three-dimensional network structure is formed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing three-dimensional silicone resins in a non-solvent system, to solve the environmental pollution problem caused by the volatilization of organic solvents in the existing preparation process of silicone resins, and to improve the safety of the preparation of silicone resins.

[0006] To achieve the above purpose, the present invention provides a method for preparing three-dimensional silicone resins in a non-solvent system, including the following steps: S1. Prepare a phosphazene chloride catalyst; S2. Add 30-50 parts of methyl orthosilicate or ethyl orthosilicate to vinyl silicone oil, and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total dosage, and heat up to colorless and transparent; S4. Add the phosphazene chloride catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature, and dropwise add deionized water, and evacuate to vacuum; S5. Add 2 - 10 parts of trimethylchlorosilane dropwise to the reaction solution obtained in S4; S6. Add silazane accounting for 1% of the total mass of the reactants dropwise to the reactants obtained in S5 to obtain a three - dimensional silicone resin.

[0007] Preferably, the S1 specifically includes the following steps: S11. Assemble the reaction device, conduct a gas - tightness inspection on the reaction device, and perform a drying treatment; S12. Purge the reaction device with nitrogen, conduct a pre - heating treatment, turn on the condensed water in the reaction device, and soak the reaction device with dichloromethane and tetrachloroethane in sequence; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass ratio and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device. Under nitrogen protection, stir and heat up to 120 - 130 °C, and then dropwise add the above - prepared tetrachloroethane solution of ammonium chloride. The mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction, cool to room temperature; S15. Add anisole to the reaction solution, stir and mix evenly under vacuum conditions to obtain phosphonitrile chloride.

[0008] Preferably, in the S14, the reaction time is 2 - 3 hours.

[0009] Preferably, in the S2, when the viscosity of vinyl silicone oil is 100 - 1000 mPa·s, a hair - type and high - speed disperser is used; when the viscosity is 1000 - 1000000 mPa·s, a kneader is used.

[0010] Preferably, in the S3, the temperature increase is 45 °C - 50 °C.

[0011] Preferably, in the S4, the dosage of phosphonitrile chloride is 50 ppm of the total input, and the mass of deionized water is 0.5% - 2% of the total mass of the reaction solution.

[0012] Preferably, in the S5, the reaction temperature is 100 °C - 120 °C, and the reaction is carried out under vacuum conditions for 1 hour.

[0013] Preferably, in the S6, the silazane is hexamethyldisilazane or tetramethyldisilazane, the reaction temperature is 100 °C - 120 °C, and the reaction is carried out under vacuum conditions for 1 hour.

[0014] The advantages and positive effects of the method for preparing a three - dimensional silicone resin in a non - solvent system according to the present invention are: 1. The present invention uses vinyl silicone oil to replace traditional volatile solvents as a carrier, and undergoes hydrolysis and condensation of methyl orthosilicate or ethyl orthosilicate in the vinyl silicone oil to form a three-dimensional silicone resin, avoiding the safety hazards and environmental emissions caused by the use of volatile solvents. Vinyl silicone oil only serves as a carrier for the condensation of three-dimensional polysiloxane and does not participate in chemical reactions. Since many downstream applications of silicone resin are in the scenario of vinyl polysiloxane, vinyl silicone oil can participate in downstream reactions and also avoid the VOC and safety hazards caused by the volatilization of solvents in actual downstream applications.

[0015] 2. The orthosilicate undergoes hydrolysis and condensation under the catalysis of phosphoric acid and phosphonitrile chloride to form a Si-O-Si three-dimensional network; trimethylcyanosilane is used as a capping agent to control the crosslinking density, and silazane further eliminates residual hydroxyl groups to improve the stability of the product. Detailed implementation mode

[0016] The technical solution of the present invention is further described below through examples.

[0017] Example 1 A preparation method of three-dimensional silicone resin in a non-solvent system includes the following steps: S1. Prepare a phosphonitrile chloride catalyst.

[0018] The preparation of the phosphonitrile chloride catalyst specifically includes the following steps: S11. Assemble the reaction device, check the airtightness of the reaction device, and perform a drying treatment; S12. Purge the reaction device with nitrogen, perform a preheating treatment, turn on the condensed water in the reaction device, and infiltrate the reaction device with dichloromethane and tetrachloroethane in sequence; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass ratio and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device, stir and heat to 120 - 130 °C under nitrogen protection, then dropwise add the above-prepared tetrachloroethane solution of ammonium chloride, and the mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction is completed, cool to room temperature; S15. Add anisole to the reaction solution, stir and mix evenly under vacuum conditions to obtain phosphonitrile chloride.

[0019] S2. Add 30 parts of methyl orthosilicate to vinyl silicone oil with a viscosity of 300 in a high-speed disperser and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total input, and heat to 45 °C until it becomes colorless and transparent.

[0020] S4. Add the phosphorus nitride chloride catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature at 45 °C, and dropwise add deionized water. The mass of the deionized water is 0.5% - 2% of the total mass of the reaction solution, and then evacuate. The dosage of the phosphorus nitride chloride is 50 ppm of the total dosage.

[0021] S5. Dropwise add 10 parts of trimethylchlorosilane to the reaction solution obtained in S4; the reaction temperature is 100 - 120 °C, and react for 1 hour under vacuum conditions.

[0022] S6. Dropwise add hexamethyldisilazane accounting for 1% of the total mass of the reactants to the reactants obtained in S5, the reaction temperature is 110 °C, and react for 1 hour under vacuum conditions to obtain three-dimensional silicone resin.

[0023] Example 2 A method for preparing three-dimensional silicone resin in a non-solvent system, comprising the following steps: S1. Prepare the phosphorus nitride chloride catalyst.

[0024] The preparation of the phosphorus nitride chloride catalyst specifically includes the following steps: S11. Assemble the reaction device, check the airtightness of the reaction device, and perform drying treatment; S12. Purge the reaction device with nitrogen, and perform preheating treatment. Turn on the condensed water in the reaction device, and soak the reaction device with dichloromethane and tetrachloroethane in sequence; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device, under nitrogen protection, stir and heat up to 120 - 130 °C, and then dropwise add the above-prepared tetrachloroethane solution of ammonium chloride. The mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction is completed, cool to room temperature; S15. Add anisole to the reaction solution, and stir and mix evenly under vacuum conditions to obtain phosphorus nitride chloride.

[0025] S2. Add 30 parts of tetraethyl orthosilicate to vinyl silicone oil with a viscosity of 300 in a high-speed disperser, and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total dosage, and heat up to 45 °C until it is colorless and transparent.

[0026] S4. Add the phosphorus nitride chloride catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature at 45 °C, and dropwise add deionized water. The mass of the deionized water is 0.5% - 2% of the total mass of the reaction solution, and then evacuate. The dosage of the phosphorus nitride chloride is 50 ppm of the total dosage.

[0027] S5. Add 5 parts of trimethylchlorosilane dropwise to the reaction solution obtained in S4; the reaction temperature is 100 - 120°C, and the reaction is carried out under vacuum conditions for 1 hour.

[0028] S6. Add tetramethyldisilazane accounting for 1% of the total mass of the reactants dropwise to the reactants obtained in S5, the reaction temperature is 100 - 120°C, and the reaction is carried out under vacuum conditions for 1 hour to obtain a three-dimensional silicone resin.

[0029] Example 3 A method for preparing a three-dimensional silicone resin in a non-solvent system, comprising the following steps: S1. Prepare a phosphorus nitride chloride catalyst.

[0030] The preparation of the phosphorus nitride chloride catalyst specifically includes the following steps: S11. Assemble the reaction device, check the airtightness of the reaction device, and perform a drying treatment; S12. Purge the reaction device with nitrogen, and perform a preheating treatment. Turn on the condensed water in the reaction device, and soak the reaction device with dichloromethane and tetrachloroethane in sequence; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass ratio and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device. Under nitrogen protection, stir and heat up to 120 - 130°C, and then dropwise add the above-prepared tetrachloroethane solution of ammonium chloride. The mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction is completed, cool to room temperature; S15. Add anisole to the reaction solution, and stir and mix evenly under vacuum conditions to obtain phosphorus nitride chloride.

[0031] S2. Add 40 parts of tetraethyl orthosilicate to vinyl silicone oil with a viscosity of 300 in a high-speed disperser, and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total dosage, and heat up to 45°C until it is colorless and transparent.

[0032] S4. Add the phosphorus nitride chloride catalyst prepared in S1 to the reaction solution of S3, stir evenly, maintain the temperature at 45°C, and dropwise add deionized water. The mass of deionized water is 0.5% - 2% of the total mass of the reaction solution, and evacuate. The dosage of phosphorus nitride chloride is 50 ppm of the total dosage.

[0033] S5. Add 3 parts of trimethylchlorosilane dropwise to the reaction solution obtained in S4; the reaction temperature is 100 - 120°C, and the reaction is carried out under vacuum conditions for 1 hour.

[0034] S6. Add tetramethyldisilazane accounting for 1% of the total mass of the reactants to the reactants obtained in S5, react at a reaction temperature of 100 - 120 °C for 1 hour under vacuum conditions to obtain a three-dimensional silicone resin.

[0035] Example 4 A method for preparing a three-dimensional silicone resin in a non-solvent system, comprising the following steps: S1. Prepare a phosphorus nitride chloride catalyst.

[0036] The preparation of the phosphorus nitride chloride catalyst specifically includes the following steps: S11. Assemble the reaction device, conduct a gas tightness inspection on the reaction device, and perform a drying treatment; S12. Purge the reaction device with nitrogen, and perform a preheating treatment. Turn on the condensed water in the reaction device, and infiltrate the reaction device with dichloromethane and tetrachloroethane in sequence; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass ratio and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device. Under nitrogen protection, stir and heat up to 120 - 130 °C, then dropwise add the above-prepared tetrachloroethane solution of ammonium chloride. The mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction, cool to room temperature; S15. Add anisole to the reaction solution, stir and mix evenly under vacuum conditions to obtain phosphorus nitride chloride.

[0037] S2. Add 50 parts of tetraethyl orthosilicate to vinyl silicone oil with a viscosity of 300 in a high-speed disperser, and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total input. Heat up to 45 °C until it is colorless and transparent.

[0038] S4. Add the phosphorus nitride chloride catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature at 45 °C, and dropwise add deionized water. The mass of deionized water is 0.5% - 2% of the total mass of the reaction solution. Evacuate. The dosage of phosphorus nitride chloride is 50 ppm of the total input.

[0039] S5. Dropwise add 5 parts of trimethylchlorosilane to the reaction solution obtained in S4; react at a reaction temperature of 100 - 120 °C for 1 hour under vacuum conditions.

[0040] S6. Add hexamethyldisilazane accounting for 1% of the total mass of the reactants to the reactants obtained in S5, react at a reaction temperature of 100 - 120 °C for 1 hour under vacuum conditions to obtain a three-dimensional silicone resin.

[0041] Example 5 A preparation method of three-dimensional silicone resin in a non-solvent system, comprising the following steps: S1. Prepare a phosphonitrile chloride catalyst.

[0042] The preparation of the phosphonitrile chloride catalyst specifically comprises the following steps: S11. Assemble the reaction device, check the airtightness of the reaction device, and perform a drying treatment; S12. Purge the reaction device with nitrogen, perform a preheating treatment, turn on the condensed water in the reaction device, and sequentially soak the reaction device with dichloromethane and tetrachloroethane; S13. Mix 160:10 - 11 of tetrachloroethane and ammonium chloride by mass and stir evenly to obtain a tetrachloroethane solution of ammonium chloride; S14. Add phosphorus pentachloride to the reaction device, stir and heat up to 120 - 130 °C under nitrogen protection, then dropwise add the above-prepared tetrachloroethane solution of ammonium chloride, and the mass ratio of phosphorus pentachloride to ammonium chloride is 5:1 - 3. After the reaction is completed, cool to room temperature; S15. Add anisole to the reaction solution, stir and mix evenly under vacuum conditions to obtain phosphonitrile chloride.

[0043] S2. Add 40 parts of methyl orthosilicate to vinyl silicone oil with a viscosity of 300 in a high-speed disperser, and stir and mix evenly; S3. Add phosphoric acid to the solution obtained in S2 and stir evenly. The dosage of phosphoric acid is 30 ppm of the total input. Heat up to 45 °C until it is colorless and transparent.

[0044] S4. Add the phosphonitrile chloride catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature at 45 °C, and dropwise add deionized water. The mass of deionized water is 0.5% - 2% of the total mass of the reaction solution. Evacuate. The dosage of phosphonitrile chloride is 50 ppm of the total input.

[0045] S5. Dropwise add 5 parts of trimethylchlorosilane to the reaction solution obtained in S4; the reaction temperature is 100 - 120 °C, and react for 1 hour under vacuum conditions.

[0046] S6. Dropwise add 1% of hexamethyldisilazane based on the total mass of the reactants to the reactants obtained in S5. The reaction temperature is 100 - 120 °C, and react for 1 hour under vacuum conditions to obtain three-dimensional silicone resin.

[0047] Study the properties of the three-dimensional silicone resin prepared in Examples 1 - 5. Conduct an impact strength test according to the ASTM D6110 - 2017 standard, a tensile test according to the ASTM D638 - 10 standard, and a heat fusion softening point test according to the GB / T 12007.6 standard. The test results are shown in Table 1.

[0048] Table 1 Performance of the three-dimensional silicone resin prepared in Examples 1-5

[0049] As can be seen from Table 1, the three-dimensional silicone resin prepared by the present invention has high impact strength, tensile strength and elongation at break, indicating that the three-dimensional silicone resin prepared by the present invention has good toughness.

[0050] Therefore, by adopting the preparation method of the three-dimensional silicone resin in the above non-solvent system, the present invention can solve the environmental pollution problem caused by the volatilization of organic solvents in the existing silicone resin preparation process and improve the safety of silicone resin preparation. The three-dimensional silicone resin prepared by the present invention has high impact strength and tensile strength and good toughness.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a three-dimensional silicone resin in a non-solvent system, characterized in that: The following steps are involved: S1, preparing chlorophosphazene catalyst; S2. Add 30-50 parts of methyl orthosilicate or ethyl orthosilicate to the vinyl silicone oil and stir to mix evenly; S3, add phosphoric acid to the solution obtained in S2 and stir evenly, the amount of phosphoric acid used is 30ppm of the total amount, and heat until it becomes colorless and transparent; S4, add the chlorophosphazene catalyst prepared in S1 to the reaction solution in S3, stir evenly, maintain the temperature, add deionized water dropwise, and evacuate; S5, adding 2-10 parts of trimethylsilyl chloride dropwise to the reaction solution obtained in S4; S6. Add silazane accounting for 1% of the total mass of the reactants dropwise to the reactants obtained in S5 to obtain a three-dimensional silicone resin.

2. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: The S1 specifically includes the following steps: S11, assembling the reaction device, performing an airtightness inspection on the reaction device, and performing a drying process; S12, purging the reaction device with nitrogen, and performing preheating treatment, opening the condensed water in the reaction device, and soaking the reaction device with dichloromethane and tetrachloroethane respectively; S13, mixing tetrachloroethane and ammonium chloride in a mass ratio of 160:10-11 and stirring evenly to prepare a tetrachloroethane solution of ammonium chloride; S14, add phosphorus pentachloride to the reaction device, stir and heat to 120-130°C under nitrogen protection, then dropwise add the tetrachloroethane solution of ammonium chloride prepared above, the mass ratio of phosphorus pentachloride to ammonium chloride is 5:1-3, and cool to room temperature after the reaction is completed; S15. Add anisole to the reaction solution, and stir and mix evenly under vacuum conditions to obtain phosphazene chloride.

3. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In the S14, the reaction time is 2-3 hours.

4. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In S2, when the viscosity of the vinyl silicone oil is 100-1000 mPa·s, a high-speed disperser is used, and when the viscosity is 1000-1000000 mPa·s, a kneader is used.

5. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In S3, the temperature is raised to 45°C-50°C.

6. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In S4, the amount of phosphazene chloride used is 50 ppm of the total amount, and the mass of deionized water is 0.5%-2% of the total mass of the reaction solution.

7. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In S5, the reaction temperature is 100° C.-120° C., and the reaction is carried out under vacuum conditions for 1 hour.

8. The method for preparing a three-dimensional silicone resin in a non-solvent system according to claim 1, characterized in that: In the S6, the silazane is hexamethyldisilazane or tetramethyldisilazane, the reaction temperature is 100° C.-120° C., and the reaction is carried out under vacuum conditions for 1 hour.

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