Preparation method of low-viscosity 107 silicone rubber

A silicone rubber, low-viscosity technology, used in the preparation of low-viscosity 107 silicone rubber, can solve problems such as difficulty in increasing viscosity accurately 107 viscosity, reducing yield, etc. Effect

Active Publication Date: 2015-12-09
SHANDONG DONGYUE ORGANIC SILICON MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using potassium hydroxide and other alkaline substances as catalysts will produce rings in the reaction and reduce the yield. Due to the strong alkalinity, the catalyzed polymerization reaction will be faster, and the viscosity will increase too fast and it is difficult to be precise. 107 Viscosity issues, especially when preparing low viscosity 107 silicone rubber, and the catalyst must be neutralized

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Hydrolyze dimethyldichlorosilane to obtain a hydrolyzate, distill off cyclosiloxane to obtain a linear body with a viscosity of 78mPa.s; add 2000Kg of linear body and 60Kg of sodium carbonate to the reaction kettle, raise the temperature to 200°C, and stir For the reaction, keep a negative pressure of -0.04MPa in the reaction kettle to continuously release water. During the reaction process, the viscosity continued to increase, and the viscosity was detected online. After the viscosity reached the predetermined viscosity of 800mPa.s, the normal pressure in the reactor was restored, filtered, and vacuumed at 150°C to remove low-molecular substances (mainly water) to obtain the product 107 The silicon rubber has a yield of 96.3% and a viscosity of 773mPa.s.

Embodiment 2

[0028] Dimethyldichlorosilane is hydrolyzed to obtain a hydrolyzate, and cyclosiloxane is distilled to obtain a linear body with a viscosity of 50mPa.s; 2000Kg of the linear body and all the sodium carbonate filtered in Example 1 are added to the reactor, Raise the temperature to 210°C, stir and react, and maintain a negative pressure of -0.05MPa in the reactor to continuously remove water. During the reaction process, the viscosity continued to increase, and the viscosity was detected online. After the viscosity reached the predetermined viscosity of 300mPa.s, the normal pressure in the reactor was restored, filtered, and vacuumed at 160°C to remove low-molecular (mainly water) substances to obtain the product 107 The silicon rubber has a yield of 97.6% and a viscosity of 313mPa.s.

Embodiment 3

[0030] Hydrolyze dimethyldichlorosilane to obtain a hydrolyzate, distill off cyclosiloxane to obtain a linear body with a viscosity of 120mPa.s; add 2000Kg of linear body and 40Kg of potassium carbonate to the reaction kettle, raise the temperature to 170°C, and stir For the reaction, keep a negative pressure of -0.06MPa in the reaction kettle to continuously release water. During the reaction process, the viscosity is continuously increasing, and the viscosity is detected online. After the viscosity reaches the predetermined viscosity of 1500mPa.s, the normal pressure in the reactor is restored, filtered, and the low-molecular (mainly water) substances are removed by vacuuming at 150°C to obtain the product 107 The silicon rubber has a yield of 97.9% and a viscosity of 1462mPa.s.

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Abstract

The invention belongs to the field of polysiloxane synthesis technologies, and particularly relates to a preparation method of low-viscosity 107 silicone rubber. According to the method, dimethyl dichlorosilane is hydrolyzed, an annulus body and a linear body are separated, carbonate is added into the separated-out linear body, temperature is raised to conduct reaction under negative pressure, the negative pressure is restored to normal pressure after viscosity reaches 300-1500 Pa.s, and low-molecular substances are drawn out through filtration to obtain the product. The viscosity of the prepared low-viscosity 107 silicone rubber is 300-1500 Pa.s and can be easily and accurately controlled, and reaction is mild. No low-molecular cyclosiloxane is generated in reaction, and the yield is greatly increased and reaches above 96%. A catalyst can be removed just through filtration and can also be recycled.

Description

technical field [0001] The invention belongs to the technical field of polysiloxane synthesis, and in particular relates to a preparation method of low-viscosity 107 silicone rubber. Background technique [0002] Polydimethylsiloxane with a viscosity of 300-1500mPa.s hydroxyl-terminated polydimethylsiloxane is often called low-viscosity 107 silicone rubber. It is the basic compound for preparing low-viscosity condensation-type RTV silicone rubber. It is widely used in the field of silicone rubber for electronics. Many, the mainstream synthesis method is to use cyclosiloxane as raw material, carry out ring-opening polymerization reaction, and add water to degrade it. [0003] The technology of preparing 107 silicone rubber from linear bodies mainly uses potassium hydroxide or tetramethylammonium hydroxide as a catalyst to catalyze the polycondensation of terminal hydroxyl groups. ): 20~22) 107 silicone rubber of 4500~88000mPa.s was synthesized with potassium hydroxide as a c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/06
Inventor 刘海龙张海磊周磊伊港朱永和
Owner SHANDONG DONGYUE ORGANIC SILICON MATERIAL
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