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Preparation method for 107 silicon rubber with controllable viscosity

A technology of silicone hydroxyl sealing and polydimethylsiloxane, which is applied in the field of polydimethylsiloxane preparation technology, can solve the problems of difficult dispersion, low reactivity, poor product transparency, etc., and save production costs , Improve product quality and improve production efficiency

Active Publication Date: 2010-12-29
浙江中天东方氟硅材料股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, sodium carbonate cannot completely remove the chloride ions in the hydrolyzate, so the chloride ion content is generally high, generally around 1000ppm in China, and above 200ppm in foreign countries. High chloride ion content will inevitably affect the polymerization speed, viscosity or degree of polymerization of the hydrolyzate. , because the added basic catalyst will be consumed by chloride ions first
And adopt KOH aqueous solution as catalyzer, because potassium hydroxide aqueous solution density is bigger than hydrolyzate, easily settle to the bottom of the kettle, heterogeneous reaction, low reactivity, make the add-on of catalyzer also also can be more than actual requirement, catalyzer and medium The blending agent is in the form of an aqueous solution, which is difficult to disperse evenly in the reaction system, and the resulting potassium salt particles are large and numerous, making the product less transparent
In addition, there will be residual trimethoxysiloxane and other trifunctional impurities in the hydrolyzate to crosslink the product, thereby affecting the quality of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Add 3500g of dimethyldichlorosilane hydrolyzate and 70g of 5% NaOH solution into a 5000mL reactor, stir, control the temperature at 90°C, react for 3 hours, separate and remove the water layer, wash the hydrolyzate with distilled water until neutral . The temperature is controlled at 70°C, and the water is removed under a vacuum of 0.05 MPa. The low boiling water carried by the removed water is returned to the reaction kettle through the balance tube. Then heat up to 110°C, spray 7g of alkali glue with a concentration of 1% tetramethylammonium hydroxide, catalyze polymerization, and control it with an online viscometer. When the viscosity increases to the required viscosity, continue to heat up to 180°C, and control the vacuum degree to 0.095 Above MPa, decompose the catalyst and remove low molecules at the same time to obtain good transparency and viscosity of 5000-200000mm 2 / s 107 silicone rubber.

Embodiment 2

[0013] Add 3500g of dimethyldichlorosilane hydrolyzate and 105g of 5% NaOH solution into a 5000mL reactor, stir, control the temperature at 90°C, react for 2 hours, separate and remove the water layer, wash the hydrolyzate with distilled water until neutral . The temperature is controlled at 70°C, and the water is removed under a vacuum of 0.05 MPa. The low boiling water carried by the removed water is returned to the reaction kettle through the balance tube. Then heat up to 100°C, spray and add 14g of alkali glue with a concentration of 1% tetramethylammonium hydroxide, catalyze polymerization, and control it with an online viscometer. When the viscosity increases to the required viscosity, continue to heat up to 180°C, and control the vacuum degree to 0.095 Above MPa, decompose the catalyst and remove low molecules at the same time to obtain good transparency and viscosity of 5000-200000mm 2 / s 107 silicone rubber.

Embodiment 3

[0015] Add 3500g dimethyldichlorosilane hydrolyzate and 140g 5% NaOH solution into a 5000mL reactor, stir, control the temperature at 90°C, react for 2 hours, separate and remove the water layer, wash the hydrolyzate with distilled water until neutral . The temperature is controlled at 70°C, and the water is removed under a vacuum of 0.05 MPa. The low boiling water carried by the removed water is returned to the reaction kettle through the balance tube. Then heat up to 120°C, spray and add 28g of alkali glue with a concentration of 1% tetramethylammonium hydroxide, catalyze polymerization, and control it with an online viscometer. When the viscosity increases to the required viscosity, continue to heat up to 180°C, and control the vacuum degree to 0.095 Above MPa, decompose the catalyst and remove low molecules at the same time to obtain good transparency and viscosity of 5000-200000mm 2 / s 107 silicone rubber.

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Abstract

The invention relates to a method for producing linear hydroxyl-terminated polydimethylsiloxane, wherein the method comprises the following steps of: washing dimethyldichlorosilane hydrolysate serving as an initiative material to remove remained chloride ions; polymerizing the hydrolyzate in the presence of a basic size catalyst; after the polymerization reaches a certain degree, heating directly to decompose catalyze; ending the reaction; and removing low-boiling matters at the same time to obtain products. The linear hydroxyl-terminated polydimethylsiloxane produced by the invention has the characteristics of uniformly distributed molecular weight, controllable viscosity, good repeatability and the like.

Description

technical field [0001] The present invention relates to a preparation process of linear silanol-terminated polydimethylsiloxane, to be precise, it relates to a preparation process of silanol-terminated polydimethylsiloxane with controllable viscosity and good reproducibility starting from cheap raw materials. The preparation process of oxane. Background technique [0002] 107 silicone rubber is a special rubber that can be vulcanized at room temperature, also known as silicone room temperature rubber. It has the advantages that natural rubber and other rubbers do not have. It has the widest working temperature range (-100 degrees to 350 degrees), Excellent radiation resistance, high and low temperature resistance, and it has excellent thermal stability, electrical insulation, weather resistance, ozone resistance, air permeability, high transparency, tear strength, excellent heat dissipation and excellent bonding In the temperature range of use, silicone rubber can not only ...

Claims

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Application Information

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IPC IPC(8): C08G77/16C08G77/08
Inventor 汤月明倪勇陈科峰杨庆红蔡昭军张飞豹吕素芳
Owner 浙江中天东方氟硅材料股份有限公司
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