Synthesis method of medium-flexural vinyl silicone resin

Abstract

The synthesis method comprises the following steps: mixing tetramethyldivinyldisiloxane with methanol, water and a solvent, adding trifluoromethanesulfonic acid as a catalyst, dropwise adding a mixture of methyltrimethoxysilane and phenyltrimethoxysilane while controlling the material temperature to be less than 15 DEG C, after dropwise adding is completed, adding trimethyltrimethoxysilane and phenyltrimethoxysilane into the mixture, and reacting for 1-2 hours at the temperature of 20-30 DEG C to obtain the medium-refractive-index vinyl silicone resin. Raising the temperature to 60 DEG C under a stirring condition, and refluxing for 3 hours; performing circulating washing purification on the reaction material through anion-cation exchange resin; adding a 25% KOH alcoholic solution as a catalyst into the reaction material, installing a water distribution device, and refluxing at 100 DEG C for 1-3 hours to obtain a polycondensation material; cooling the polycondensation material to below 60 DEG C, adding acetic acid for neutralization, and carrying out circulating washing purification through the anion-cation exchange resin until the conductivity is less than 5 us / cm and the pH is 5-7; filtering the polycondensation material; and maintaining the vacuum degree of 100-101.325 kPa at 110-120 DEG C, carrying out reduced pressure distillation for 1-3 hours, removing the solvent and low molecules, and finally cooling to obtain a target product, namely the medium-refractive MT vinyl silicone resin.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical industry, in particular to a method for synthesizing a folded vinyl silicone resin. Background Art

[0002] MT vinyl silicone resin is composed of monofunctional M units (Vi(CH3)2SiO1 / 2), trifunctional T units (PhSiO3 / 2), and trifunctional T units (CH3SiO3 / 2). Its vinyl end groups impart excellent crosslinking and adhesion properties, making it widely used in LED encapsulants, addition-type silicone rubber, semiconductor packaging materials, and specialty adhesives. Traditional synthesis methods easily gelate due to the difference in polymerization rates between the trifunctional T units (PhSiO3 / 2) and CH3SiO3 / 2, making its refractive index difficult to control. Furthermore, the synthesis of MT vinyl silicone resin produces a significant amount of wastewater. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for synthesizing a folded vinyl silicone resin, comprising the following steps: Step 1, dropwise hydrolysis: tetramethyldivinyldisiloxane was mixed with methanol, water, and a solvent, trifluoromethanesulfonic acid was added as a catalyst, and a mixture of methyltrimethoxysilane and phenyltrimethoxysilane was added dropwise. During the addition, the reaction material temperature was controlled to be less than 15°C. After the addition was completed, the temperature was raised to 60°C under stirring and refluxed for 3 hours; Step 2: Water washing and purification: The reaction material is circulated and washed with anion and cation exchange resins until its conductivity is less than 5 μS / cm and the pH is 5-7; Step 3, water separation and polycondensation: add 25% KOH alcohol solution as a catalyst to the reaction material, install a water separation device, and reflux at 100°C for 1-3 hours to obtain a polycondensation material; Step 4: Neutralization and water washing: The polycondensation material is cooled to below 60°C and neutralized by adding acetic acid. After neutralization, it is again purified by circulating water washing with anion and cation exchange resin until its conductivity is less than 5 μS / cm and the pH is 5-7. Step 5, filtration: filtering the polycondensation material; Step 6: Vacuum desolventization: Maintain vacuum degree of 100-101.325 kPa at 110-120°C and perform reduced pressure distillation for 1-3 hours to remove the solvent and low molecular weight molecules. Finally, cool the mixture to obtain the target product, the MT vinyl silicone resin.

[0004] Furthermore, in the step 1, 37.28 g of tetramethyldivinyldisiloxane, 192 g of methanol, 108 g of deionized water, and 0.4 g of trifluoromethanesulfonic acid were added to a 4-necked 1 L flask equipped with a thermometer, a mechanical stirrer, an isobaric dropping funnel, and a condenser.

[0005] Furthermore, in the step 1, while stirring the components, a mixture of 198.29 g of phenyltrimethoxysilane and 136.22 g of methyltrimethoxysilane was added dropwise over 5 hours.

[0006] Furthermore, in the step 2, 300 g of toluene was added to the reaction material for dilution, and then 300 g of deionized water was added, and then the reaction material was transferred to a separatory funnel, the aqueous phase was removed, and then 300 g of deionized water was added, and the reaction material was washed and purified by anion and cation exchange resin until the conductivity was <5 us / cm and the pH was 5-7.

[0007] Furthermore, in the step 3, 3 g of 25% KOH alcohol solution was added to the reaction material.

[0008] Furthermore, in the step 4, 0.8 g of glacial acetic acid is added to the polycondensation material, stirred for 1 hour, and then washed and purified with an anion and cation exchange resin.

[0009] Furthermore, in the step five, the condensation material is filtered using a sand core filter device.

[0010] The beneficial effects of the present invention compared with the prior art are: (1) the present invention has no gelation phenomenon in terms of gel control; (2) the wastewater generated by the present invention is much less than that of the traditional synthesis method. DETAILED DESCRIPTION

[0011] The technical solution of the present invention is further illustrated below through specific implementation methods. Example

[0012] A method for synthesizing a mid-fold vinyl silicone resin comprises the following steps: Step 1, dropwise hydrolysis: In a 4-neck 1L flask equipped with a thermometer, a mechanical stirrer, an isobaric dropping funnel and a condenser, 37.28g of tetramethyldivinyldisiloxane, 192g of methanol, 108g of deionized water, and 0.4g of trifluoromethanesulfonic acid as a catalyst were added. While stirring the components, a mixture of 198.29g of phenyltrimethoxysilane and 136.22g of methyltrimethoxysilane was added dropwise over 5 hours. During this period, the reaction material temperature was controlled to <15°C. After the addition was completed, the temperature was raised to 60°C under stirring and refluxed for 3h.

[0013] Step 2: Water washing and purification: 300 g of toluene was added to the reaction material for dilution, and then 300 g of deionized water was added. The reaction material was then transferred to a separatory funnel, the aqueous phase was removed, and 300 g of deionized water was added. The reaction material was circulated and washed with an anion and cation exchange resin for purification until its conductivity was <5 μS / cm and the pH was 5-7.

[0014] Step 3, water separation and polycondensation: add 3g of 25% KOH alcohol solution as a catalyst to the reaction material, install a water separation device, and reflux at 100°C for 3h to obtain a polycondensation material; Step 4: Neutralization and water washing: The polycondensation material is cooled to below 60°C, 0.8g of glacial acetic acid is added for neutralization, and stirred for 1 hour. After neutralization, it is again purified by circulating water washing with anion and cation exchange resin until its conductivity is less than 5 μS / cm and the pH is 5-7.

[0015] Step 5: Filtration: Filter the polycondensate using a sand core filter.

[0016] Step 6: Vacuum desolventization: Maintain vacuum at 100-101.325 kPa for 1-3 hours at 110-120°C to remove solvent and low molecular weight products. Remove low boiling points from the filtrate by vacuum and cool to obtain the target product, MT vinyl silicone resin.

[0017] This method uses methyltrimethoxysilane, phenyltrimethoxysilane, and tetramethyldivinyldisiloxane as raw materials, and synthesizes them by adding methanol, controlling the low temperature during the hydrolysis equilibrium process, and purifying them with anion and cation exchange resins, thereby achieving a refractive index of 1.47-1.49, without gel, and significantly reducing wastewater.

[0018] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for synthesizing a folded vinyl silicone resin, characterized in that: The following steps are involved: Step 1, dropwise hydrolysis: tetramethyldivinyldisiloxane was mixed with methanol, water, and a solvent, trifluoromethanesulfonic acid was added as a catalyst, and a mixture of methyltrimethoxysilane and phenyltrimethoxysilane was added dropwise. During the addition, the reaction material temperature was controlled to be less than 15°C. After the addition was completed, the temperature was raised to 60°C under stirring and refluxed for 3 hours; Step 2: Water washing and purification: The reaction material is circulated and washed with anion and cation exchange resins until its conductivity is less than 5 μS / cm and the pH is 5-7; Step 3, water separation and polycondensation: add 25% KOH alcohol solution as a catalyst to the reaction material, install a water separation device, and reflux at 100°C for 1-3 hours to obtain a polycondensation material; Step 4: Neutralization and water washing: The polycondensation material is cooled to below 60°C and neutralized by adding acetic acid. After neutralization, it is again purified by circulating water washing with anion and cation exchange resin until its conductivity is less than 5 μS / cm and the pH is 5-7. Step 5, filtration: filtering the polycondensation material; Step 6: Vacuum desolventization: Maintain vacuum degree of 100-101.325 kPa at 110-120°C and perform reduced pressure distillation for 1-3 hours to remove the solvent and low molecular weight molecules. Finally, cool the mixture to obtain the target product, the MT vinyl silicone resin.

2. The method for synthesizing a folded vinyl silicone resin according to claim 1, wherein: In the step 1, 37.28 g of tetramethyldivinyldisiloxane, 192 g of methanol, 108 g of deionized water, and 0.4 g of trifluoromethanesulfonic acid were added to a 1 L 4-necked flask equipped with a thermometer, a mechanical stirrer, an isobaric dropping funnel, and a condenser.

3. The method for synthesizing a folded vinyl silicone resin according to claim 2, wherein: In the step 1, while stirring the components, a mixture of 198.29 g of phenyltrimethoxysilane and 136.22 g of methyltrimethoxysilane was added dropwise over 5 hours.

4. The method for synthesizing a folded vinyl silicone resin according to claim 1, wherein: In the step 2, 300 g of toluene was added to the reaction material for dilution, and then 300 g of deionized water was added. The reaction material was then transferred to a separatory funnel, the aqueous phase was removed, and 300 g of deionized water was added. The reaction material was washed and purified by anion and cation exchange resin until the conductivity was <5 μS / cm and the pH was 5-7.

5. The method for synthesizing a folded vinyl silicone resin according to claim 1, wherein: In the step 3, 3 g of 25% KOH alcohol solution was added to the reaction material.

6. The method for synthesizing a folded vinyl silicone resin according to claim 1, wherein: In the step 4, 0.8 g of glacial acetic acid is added to the polycondensation material, stirred for 1 hour, and then washed and purified with an anion and cation exchange resin.

7. The method for synthesizing a folded vinyl silicone resin according to claim 1, wherein: In the step 5, the condensation material is filtered using a sand core filter device.