Preparation method of methyl phenyl vinyl MQ silicon resin

Abstract

The invention discloses a preparation method of methyl phenyl vinyl MQ silicon resin, which comprises the following steps: adding ethyl silicate into an organic solvent, then slowly dropwise adding an acid solution, and carrying out low-temperature ultrasonic treatment to obtain a pre-reaction solution; the preparation method comprises the following steps: adding dimethyl vinyl chlorosilane, dimethyl phenyl chlorosilane and trimethylchlorosilane into water-containing diethyl ether, and carrying out low-temperature ultrasonic dispersion to obtain a reaction precursor solution; synchronously adding the reaction precursor solution and the pre-reaction solution, reducing pressure and premixing, and carrying out constant-temperature reaction to obtain a reaction solution; purging the reaction liquid under reduced pressure, then adding toluene and water, and adjusting the pH value to be neutral; and carrying out extraction separation, washing and evaporation to obtain the methyl phenyl vinyl MQ silicon resin. The problems that the molecular weight of existing MQ silicon resin is difficult to control and similar groups are gathered are solved, connection of methyl, vinyl and phenyl on ethyl silicate hydrolysate is effectively controlled in a synchronous adding mode, the molecular weight is effectively controlled, and homogeneous dispersion is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon, and particularly relates to a preparation method of methylphenylvinyl MQ silicone resin. Background Art

[0002] At present, LED packaging materials mainly use epoxy resin, which has become the mainstream material based on electrical insulation, sealing and dielectric properties. However, epoxy resin contains a large number of aromatic rings inside, which will cause discoloration after ultraviolet irradiation. At the same time, the hotter the epoxy resin is, the more it will discolor, resulting in a decrease in light transmittance. In addition, the hygroscopicity and easy aging of epoxy resin itself will reduce the service life of the packaging material. With the development of LED technology and the expansion of its application scope, the requirements for LED packaging materials are constantly increasing, resulting in a gradual decrease in the adaptability of epoxy resin. MQ silicone resin has excellent heat resistance and high thermal stability. It can maintain good weather resistance under high temperature environment and resist the influence of ultraviolet rays, ozone, rain and other severe weather conditions. However, as an LED packaging material, it has many performance requirements and needs to be changed through many organic groups to meet different use environments. Among them, this type of MQ silicone resin is mainly methylphenyl vinyl MQ silicone resin. Our current methylphenyl vinyl MQ silicone resin has problems such as difficult to control molecular weight and aggregation and connection of similar groups. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a method for preparing a methylphenyl vinyl MQ silicone resin, which solves the problems of difficult control of molecular weight and aggregation of similar groups in the prior MQ silicone resin, and effectively controls the connection of methyl, vinyl and phenyl groups on ethyl silicate hydrolyzate by synchronous addition, which not only effectively controls the molecular weight but also achieves homogeneous dispersion.

[0004] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0005] A method for preparing methylphenyl vinyl MQ silicone resin comprises the following steps:

[0006] Step 1, adding ethyl silicate to an organic solvent and stirring evenly, then slowly dropping acid solution and performing low-temperature ultrasound for 1-2 hours to obtain a pre-reaction solution; the concentration of the ethyl silicate in the organic solvent is 200-400 g / L, the organic solvent is a mixed solution of ethanol and ether, and the volume ratio of ethanol to ether is 2:2-3, the stirring speed for uniform stirring is 300-500 r / min, the acid solution is concentrated hydrochloric acid, and the mass fraction of concentrated hydrochloric acid is 33-35%, the dropping speed of the acid solution is 1-2 mL / min, the temperature of the low-temperature ultrasound is 5-10° C., and the ultrasonic frequency is 70-90 kHz. This step utilizes the solubility of ethyl silicate in ether and ethanol to form a homogeneous dispersion, and the method of slowly dropping the acid solution not only promotes the rapid dispersion of distilled water in the organic solvent, ensures the in-situ hydrolysis of ethyl silicate, but also solves the insolubility problem of ether and distilled water;

[0007] Step 2, adding dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane to aqueous ether and stirring evenly, and obtaining a reaction precursor solution after low-temperature ultrasonic dispersion, wherein the molar ratio of the dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane is 4:2-4:3-4, and the concentration of the dimethylvinyl chlorosilane in the ether is 100-200g / L, the aqueous ether is a saturated ether liquid, the stirring speed for uniform stirring is 300-500r / min, the temperature of the low-temperature ultrasonic dispersion is 10-15°C, and the ultrasonic frequency is 70-90kH. This step utilizes the solubility of dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane in ether to form a homogeneous dispersion system, thereby ensuring the full dispersion of vinyl, phenyl and methyl groups. At the same time, the water molecules of chlorosilane in the aqueous ether form a hydrolysis reaction, thereby obtaining a reaction precursor;

[0008] Step 3, adding the reaction precursor liquid and the pre-reaction liquid simultaneously and pre-mixing them at reduced pressure, and reacting them at a constant temperature for 4-5 hours to obtain a reaction liquid, wherein the molar ratio of the solute in the reaction precursor liquid to the solute in the pre-reaction liquid is 4:1, and the simultaneous addition is synchronously added in a molar ratio manner, the temperature of the reduced pressure pre-mixing is 5-10° C., the pressure is 80-90% of the atmospheric pressure, the stirring speed is 300-500 r / min, and the temperature of the constant temperature reaction is 30-50° C.; In this step, the capping agent and the ethyl silicate hydrolyzate are formed into a proportional relationship by means of synchronous addition, and the synthetic amount of the molecular weight is controlled in a manner of increasing the amount by a small amount, thereby achieving the purpose of controlling the molecular weight, and at the same time, the ether is vaporized by means of the reduced pressure pre-mixing, and the ether is recovered in the subsequent tail gas recovery, and the ether liquid can also be recovered quickly and losslessly, thereby reducing environmental protection requirements;

[0009] Step 4, purging the reaction solution under reduced pressure for 3-5h, then adding toluene and water and adjusting the pH to neutral; extracting, separating, washing and evaporating to obtain methylphenyl vinyl MQ silicone resin, wherein the reduced pressure purging uses dry nitrogen at 40-50°C and the flow rate is 5-8mL / min, the mass ratio of toluene to water is 5:1-2, the pH is adjusted using a sodium hydroxide solution with a mass fraction of 30-40%, and the evaporation temperature is 130-140°C; in this step, ether and ethanol are gradually removed by reduced pressure purging, the addition of toluene and water can achieve a capacity expansion effect, and alkaline solution is used for pH balance at the same time, and toluene liquid is obtained by extraction, stratification and washing, and low-boiling substances are simultaneously removed during the toluene evaporation process, thereby obtaining methylphenyl vinyl MQ silicone resin liquid.

[0010] It can be seen from the above description that the present invention has the following advantages:

[0011] 1. The present invention solves the problems of difficult control of molecular weight and aggregation of similar groups in existing MQ silicone resins, and effectively controls the connection of methyl, vinyl and phenyl groups on ethyl silicate hydrolyzate by synchronous addition, which not only effectively controls the molecular weight but also realizes homogeneous dispersion.

[0012] 2. The present invention utilizes the separation of vinyl and phenyl, which effectively reduces the mutual influence between vinyl and phenyl, helps to improve the connectivity of the resin in the rubber, and achieves good curing and stability.

[0013] 3. The present invention effectively controls the MQ system reaction by low temperature, thereby reducing the problem of molecular agglomeration, providing conditions for effectively controlling the molecular weight of the MQ silicone resin, and using ether as an auxiliary solvent, which can be quickly recovered and reduce environmental pollution. DETAILED DESCRIPTION

[0014] The present invention is described in detail with reference to the embodiments, but no limitation is imposed on the claims of the present invention.

[0015] Example 1

[0016] A method for preparing methylphenyl vinyl MQ silicone resin comprises the following steps:

[0017] Step 1, adding ethyl silicate to an organic solvent and stirring evenly, then slowly dropping an acid solution and performing low-temperature ultrasound for 1 hour to obtain a pre-reaction solution; the concentration of the ethyl silicate in the organic solvent is 200 g / L, the organic solvent is a mixture of ethanol and ether, and the volume ratio of ethanol to ether is 1:1, the stirring speed for stirring evenly is 300 r / min, the acid solution is concentrated hydrochloric acid, and the mass fraction of concentrated hydrochloric acid is 33%, the dropping speed of the acid solution is 1 mL / min, the temperature of the low-temperature ultrasound is 5° C., and the ultrasonic frequency is 70 kHz;

[0018] Step 2, adding dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane to aqueous ether and stirring evenly, and obtaining a reaction precursor solution after low-temperature ultrasonic dispersion, wherein the molar ratio of dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane is 4:2:3, and the concentration of dimethylvinyl chlorosilane in ether is 100 g / L, the aqueous ether is a saturated ether solution, the stirring speed for uniform stirring is 300 r / min, the temperature of the low-temperature ultrasonic dispersion is 10° C., and the ultrasonic frequency is 70 kHz;

[0019] Step 3, the reaction precursor liquid and the pre-reaction liquid are added simultaneously and the pressure is reduced and pre-mixed, and the reaction is carried out at a constant temperature for 4 hours to obtain a reaction liquid, the molar ratio of the solute in the reaction precursor liquid to the solute in the pre-reaction liquid is 4:1, and the synchronous addition is added synchronously according to the molar ratio, the temperature of the depressurized premix is ​​5°C, the pressure is 80% of the atmospheric pressure, the stirring speed is 300r / min, and the temperature of the constant temperature reaction is 30°C;

[0020] Step 4, purging the reaction solution under reduced pressure for 3 hours, then adding toluene and water and adjusting the pH to neutral; obtaining methylphenyl vinyl MQ silicone resin through extraction separation, washing and evaporation, wherein the reduced pressure purging adopts dry nitrogen at 40°C and the flow rate is 5 mL / min, the mass ratio of toluene to water is 5:1, the pH is adjusted using a sodium hydroxide solution with a mass fraction of 30%, and the evaporation temperature is 130°C.

[0021] Example 2

[0022] A method for preparing methylphenyl vinyl MQ silicone resin comprises the following steps:

[0023] Step 1, adding ethyl silicate to an organic solvent and stirring evenly, then slowly dropping an acid solution and performing low-temperature ultrasound for 2 hours to obtain a pre-reaction solution; the concentration of the ethyl silicate in the organic solvent is 400 g / L, the organic solvent is a mixture of ethanol and ether, and the volume ratio of ethanol to ether is 2:3, the stirring speed for stirring evenly is 500 r / min, the acid solution is concentrated hydrochloric acid, and the mass fraction of concentrated hydrochloric acid is 35%, the dropping speed of the acid solution is 2 mL / min, the temperature of the low-temperature ultrasound is 10° C., and the ultrasonic frequency is 90 kHz;

[0024] Step 2, adding dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane to aqueous ether and stirring evenly, and obtaining a reaction precursor solution after low-temperature ultrasonic dispersion, wherein the molar ratio of dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane is 1:1:1, and the concentration of dimethylvinyl chlorosilane in ether is 200g / L, the aqueous ether is a saturated ether solution, the stirring speed for uniform stirring is 500r / min, the temperature of the low-temperature ultrasonic dispersion is 15°C, and the ultrasonic frequency is 90kH;

[0025] Step 3, adding the reaction precursor liquid and the pre-reaction liquid simultaneously and reducing the pressure to premix, reacting at a constant temperature for 5 hours to obtain a reaction liquid, wherein the molar ratio of the solute in the reaction precursor liquid to the solute in the pre-reaction liquid is 4:1, and the simultaneous addition is added simultaneously according to the molar ratio, the temperature of the reduced pressure premix is ​​10° C., the pressure is 90% of the atmospheric pressure, the stirring speed is 500 r / min, and the temperature of the constant temperature reaction is 50° C.;

[0026] Step 4, purging the reaction solution under reduced pressure for 3-5h, then adding toluene and water and adjusting the pH to neutral; obtaining methylphenyl vinyl MQ silicone resin through extraction separation, washing and evaporation, wherein the reduced pressure purging adopts dry nitrogen at 50°C and the flow rate is 8mL / min, the mass ratio of toluene to water is 5:2, the pH is adjusted using a sodium hydroxide solution with a mass fraction of 40%, and the evaporation temperature is 140°C.

[0027] Example 3

[0028] A method for preparing methylphenyl vinyl MQ silicone resin comprises the following steps:

[0029] Step 1, adding ethyl silicate to an organic solvent and stirring evenly, then slowly dropping an acid solution and performing low-temperature ultrasound for 2 hours to obtain a pre-reaction solution; the concentration of the ethyl silicate in the organic solvent is 300 g / L, the organic solvent is a mixture of ethanol and ether, and the volume ratio of ethanol to ether is 2:3, the stirring speed for stirring evenly is 400 r / min, the acid solution is concentrated hydrochloric acid, and the mass fraction of concentrated hydrochloric acid is 34%, the dropping speed of the acid solution is 1 mL / min, the temperature of the low-temperature ultrasound is 8°C, and the ultrasonic frequency is 80 kHz;

[0030] Step 2, adding dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane to aqueous ether and stirring evenly, and obtaining a reaction precursor solution after low-temperature ultrasonic dispersion, wherein the molar ratio of dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane is 4:3:3, and the concentration of dimethylvinyl chlorosilane in ether is 150g / L, the aqueous ether is a saturated ether solution, the stirring speed for uniform stirring is 400r / min, the temperature of the low-temperature ultrasonic dispersion is 12°C, and the ultrasonic frequency is 80kH;

[0031] Step 3, adding the reaction precursor liquid and the pre-reaction liquid simultaneously and reducing the pressure to premix, reacting at a constant temperature for 5 hours to obtain a reaction liquid, wherein the molar ratio of the solute in the reaction precursor liquid to the solute in the pre-reaction liquid is 4:1, and the simultaneous addition is added simultaneously according to the molar ratio, the temperature of the reduced pressure premix is ​​8° C., the pressure is 85% of the atmospheric pressure, the stirring speed is 400 r / min, and the temperature of the constant temperature reaction is 40° C.;

[0032] Step 4, purging the reaction solution under reduced pressure for 3-5 hours, then adding toluene and water and adjusting the pH to neutral; obtaining methylphenyl vinyl MQ silicone resin through extraction separation, washing and evaporation, wherein the reduced pressure purging adopts dry nitrogen at 45°C and the flow rate is 7mL / min, the mass ratio of toluene to water is 5:2, the pH is adjusted using a sodium hydroxide solution with a mass fraction of 35%, and the evaporation temperature is 135°C.

[0033] Comparative Example

[0034] The comparative example uses commercially available methylphenyl vinyl MQ silicone resin from Shandong Baihong New Materials Co., Ltd.

[0035] Performance Testing

[0036] The products of Examples 1-3 and Comparative Examples were used as test samples for performance testing, and the results are as follows:

[0037]

[0038]

[0039] Comparison of the data of the above Examples 1-3 and the comparative example shows that the present technical solution uses dispersible dimethylvinyl chlorosilane and dimethylphenyl chlorosilane as raw materials to form a dispersion of vinyl and phenyl, reduce the influence between the two, and achieve controllable content of vinyl and phenyl; at the same time, the reaction progress is controlled at low temperature to achieve controllable molecular weight.

[0040] It is understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A method for preparing a methylphenyl vinyl MQ silicone resin, characterized in that: The steps include: Step 1, adding ethyl silicate to an organic solvent and stirring evenly, then slowly dropping an acid solution and performing low temperature ultrasonication for 1-2 hours to obtain a pre-reaction solution; Step 2, adding dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethyl chlorosilane into aqueous ether and stirring evenly, and performing low-temperature ultrasonic dispersion to obtain a reaction precursor solution; Step 3, the reaction precursor solution and the pre-reaction solution are added simultaneously and pre-mixed by reducing the pressure, and reacted at a constant temperature for 4-5 hours to obtain a reaction solution; Step 4, the reaction solution is purged under reduced pressure for 3-5 hours, and then toluene and water are added and the pH is adjusted to neutral; After extraction, separation, washing and evaporation, methylphenylvinyl MQ silicone resin is obtained.

2. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The concentration of ethyl silicate in the organic solvent in step 1 is 200-400 g / L, the organic solvent is a mixture of ethanol and diethyl ether, and the volume ratio of ethanol to diethyl ether is 2:2-3, and the stirring speed for uniform stirring is 300-500 r / min.

3. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The acid solution in step 1 is concentrated hydrochloric acid, and the mass fraction of the concentrated hydrochloric acid is 33-35%. The dropping speed of the acid solution is 1-2 mL / min. The temperature of the low-temperature ultrasound is 5-10° C., and the ultrasound frequency is 70-90 kHz.

4. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The molar ratio of dimethylvinyl chlorosilane, dimethylphenyl chlorosilane and trimethylchlorosilane in step 2 is 4:2-4:3-4, and the concentration of dimethylvinyl chlorosilane in diethyl ether is 100-200 g / L.

5. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The aqueous ether in step 2 is saturated ether liquid, the stirring speed for uniform stirring is 300-500 r / min, the temperature of the low-temperature ultrasonic dispersion is 10-15° C., and the ultrasonic frequency is 70-90 kH.

6. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The molar ratio of the solute in the reaction precursor solution to the solute in the pre-reaction solution in step 3 is 4:1, and the simultaneous addition is performed in accordance with the molar ratio.

7. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The temperature of the depressurized premix in step 3 is 5-10°C, the pressure is 80-90% of the atmospheric pressure, the stirring speed is 300-500r / min, and the temperature of the isothermal reaction is 30-50°C.

8. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The reduced pressure purging in step 4 uses dry nitrogen at 40-50° C., and the flow rate is 5-8 mL / min.

9. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The mass ratio of toluene to water in step 4 is 5:1-2, and the pH is adjusted using a sodium hydroxide solution with a mass fraction of 30-40%.

10. The method for preparing the methylphenyl vinyl MQ silicone resin according to claim 1, characterized in that: The evaporation temperature in step 4 is 130-140°C.

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