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Method for producing low-hydroxyl value high-temperature sulfuration silicon rubber raw rubber

A technology of raw silicone rubber and high-temperature vulcanization, applied in the field of silicone rubber production, can solve the problems of decreased dispersion of silica, short storage time of mixed rubber, and decreased plasticity.

Inactive Publication Date: 2008-05-07
JIANGSU HONGDA NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When this raw rubber is mixed with white carbon black and other additives to prepare mixed rubber, the Si-OH in the silicone rubber raw rubber molecules will physically or chemically combine with the active Si-OH groups on the surface of the white carbon black to form cross-linking. The combination will lead to the increase of the viscosity of the mixed rubber, the decrease of the dispersibility of the silica, the short storage time of the mixed rubber, and the gradual hardening of the rubber during the storage process, the decrease of the plasticity and the decrease of the processing performance.

Method used

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  • Method for producing low-hydroxyl value high-temperature sulfuration silicon rubber raw rubber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Press 1000kg of D4 into the dehydration kettle, depressurize, blow nitrogen, 50-60℃, dehydration for 4h, add 0.20kg of tetramethyltetravinylcyclotetrasiloxane, 2.80kg of tetramethylammonium hydroxide silicon alkoxide, 1.10kg of hexamethyldisiloxane, dehydrated below 60℃ for 40min. The dehydrated material is pressed into the polymerization kettle through the metering tank, and the temperature is raised to 100-110°C, and the double-pair spiral ribbon scraping wall stirrer is used to stir and react for 4 hours. After the polymerization is completed, the temperature of the reactor is increased to 160°C, and the vacuum pump is turned on for 2 hours. Turn off the vacuum pump, lower the temperature to below 120°C, add 300 g of hexamethyldisilazane, stir and maintain for 1 hour. The temperature of the reaction kettle was increased to 160-180°C, and the vacuum pump was turned on at the same time, stirring, and maintaining for 3 hours. Finally, cooling water is passed through the wal...

Embodiment 2

[0017] The preparation method is the same as in Example 1, except that the ingredients are changed to: D 4 Change to a mixed ring DMC 500kg (the content of D4 and D5 in the mixed ring DMC is not less than 80%, at 25℃, the viscosity is 2.10-3.50mm 2 / s), tetramethyltetravinylcyclotetrasiloxane 50kg, tetramethylammonium hydroxide silicon alkoxide 1.60kg, hexamethyldisiloxane 0.750g. The obtained raw rubber related data are shown in Table 1.

Embodiment 3

[0019] The preparation method is the same as in Example 1, except that the ingredients are changed to: DMC800kg, tetramethyltetravinylcyclotetrasiloxane 3.8kg, tetramethylammonium hydroxide siliconate 2.80kg, tetramethyldivinyldisiloxane 0.70g. The obtained raw rubber related data are shown in Table 1.

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Abstract

The invention relates to the field for producing silicon rubber, in particular to a preparation method of sulfuration silicon rubber crude rubber with low hydroxyl value high temperature. The invention adopts the method that: firstly, all materials are dehydrated before preparation and then the polyreaction is conducted; after the catalyzer loses activity caused by decomposition, the material which can react with a SiOH group is added. The silicon rubber crude rubber prepared by the invention has narrow molecular weight distribution and extremely micro-hydroxy-terminated. The invention also discloses a double-pair screw belt scraping wall type stirrer.

Description

Technical field [0001] The invention relates to the field of silicone rubber production, in particular to a preparation method of low-hydroxyl value high-temperature vulcanized silicone rubber raw rubber. Background technique [0002] The main methods for the industrial production of high-temperature vulcanized silicone rubber raw rubber are batch method and continuous method; the commonly used catalysts include tetramethylammonium hydroxide siliconate and potassium siliconate. [0003] The typical batch preparation process is: octamethylcyclotetrasiloxane (D 4 ) Or dimethyl siloxane mixed ring (DMC) is added to the polymerization vessel, the water is removed by nitrogen blowing under reduced pressure, and then heated to 90-120℃, and then the vinyl ring and tetramethylammonium hydroxide are added Siliconate, capping agent. When the polymer reaches the required viscosity, the temperature is increased to about 130-180°C for a period of time to decompose and destroy the catalyst. Fi...

Claims

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Application Information

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IPC IPC(8): C08G77/06
Inventor 朱德洪刘勇朱恩伟陈江明田月仙
Owner JIANGSU HONGDA NEW MATERIAL
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