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Method for removing medium and low-molecular-weight polysiloxane in silicone rubber

The technology of polysiloxane and hydroxy polydimethylsiloxane is applied in the field of removal of low molecular polysiloxane in silicone rubber, which can solve the problems of low molecular content that are not involved in process parameters, and achieve removal efficiency. high effect

Inactive Publication Date: 2019-03-15
南京天双辰新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The patent application publication number CN204356267U discloses a low-molecular removal device for a high-temperature silicone rubber raw rubber production system. The patent application publication number CN202620747U discloses a removal device for low-molecular substances in adhesives. A delowering device and a method for producing methyl silicone oil with a viscosity of 30 to 1,000,000 cs were developed, all using a self-made delowering device, and did not involve the specific process parameters of delowering and the actual low molecular content after delowering

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0019] Put α,ω-dihydroxypolydimethylsiloxane with a viscosity of 5000mPa·s at 25°C and a low molecular weight polysiloxane content of 18,000ppm in a vacuum oven, treat it at 100°C for 24h, and then add it to a thin film evaporator , treated 5 times at 120°C, 100Pa vacuum, 10L / h flow rate, added to the vacuum distiller again, and treated 6 times at 150°C, 150Pa vacuum, 5L / h silicone rubber flow rate to obtain low molecular polysilicone α,ω-dihydroxy polydimethylsiloxane having a viscosity of 5000 mPa·s at 25° C. with an oxane content of 100 ppm.

example 2

[0021] Put α,ω-dihydroxy polydimethylsiloxane with a viscosity of 20,000mPa·s at 25°C and a low molecular polysiloxane content of 16,000ppm in a vacuum oven, treat it at 150°C for 72h, and then add it to a thin film evaporator , treated once at 180°C, 200Pa vacuum, 5L / h flow rate, added to the short-path distiller again, and treated once at 250°C, 10Pa vacuum, 1L / h silicone rubber flow rate to obtain low molecular polysiloxane An α,ω-dihydroxy polydimethylsiloxane having a viscosity of 20,000 mPa·s at 25° C. with an alkane content of 170 ppm.

example 3

[0023] Place simethicone oil with a viscosity of 500mPa·s at 25°C and a low-molecular polysiloxane content of 22,000ppm in a vacuum oven. , 8L / h flow rate for 3 times, then added to the short-path distiller again, and treated 5 times at 200°C, 100Pa vacuum degree, and 4L / h silicone rubber flow rate to obtain a low-molecular polysiloxane content of 80ppm at 25°C. Dimethicone oil with a viscosity of 500mPa·s.

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Abstract

The invention belongs to the field of high polymer materials and relates to a method for removing medium and low-molecular-weight polysiloxane in silicone rubber. The method uses devices such as a vacuum oven, a film evaporator, a vacuum distiller and a short range distiller to remove the low-molecular-weight polysiloxane in the silicone rubber, and the required silicone rubber with the low-molecular-weight polysiloxane removed is obtained by controlling the temperature, the vacuum degree, the velocity of the silicone rubber, and the removing times. The used method for removing the low-molecular-weight polysiloxane is simple, the contents of the medium and low-molecular-weight polysiloxane in the obtained silicone rubber are controlled, and the method can be used in various fields such assilicone sealants, auto lamps, photoelectric components, and medical apparatuses and instruments.

Description

technical field [0001] The invention belongs to the field of polymer materials, in particular to a method for removing low-molecular polysiloxane in silicone rubber. Background technique [0002] Silicone rubber is widely used in many fields due to its convenient use, moderate cost and excellent performance. Silicone rubber is generally made of low-molecular-weight siloxane through ring-opening polymerization under alkali or acid catalysis. The silicone rubber prepared by this catalytic equilibrium method still contains a lot of low molecular polysiloxanes, which will gradually volatilize and escape from the silicone rubber even at normal temperature and pressure, making the silicone rubber in the application There are many defects in the process. For example, in practical application of silicone rubber, when the content of low-molecular polysiloxane is high, it is easy to cause fogging of the car lights or adhesion to the surface of the anti-fog coating, which will affect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/34
CPCC08G77/34
Inventor 刘育建
Owner 南京天双辰新材料有限公司
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