Preparation method of medium/high-viscosity alpha,omega-dihydroxypolydimethylsiloxane

A hydroxyl polydimethylsiloxane and viscosity technology, applied in the field of organic compound preparation, can solve problems such as complicated steps, and achieve the effects of short reaction time, high production efficiency and less ring content

Active Publication Date: 2013-12-04
SHANDONG DONGYUE ORGANIC SILICON MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above method not only needs to add an acidic or basic catalyst, but also needs to add a neutralizer or filter, the steps are complicated, and it needs to go through sufficient time to ensure the completion of polymerization and complete neutralization

Method used

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  • Preparation method of medium/high-viscosity alpha,omega-dihydroxypolydimethylsiloxane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1: The method for preparing medium and high viscosity α, ω-dihydroxy polydimethylsiloxane, the steps are as follows:

[0028] (1) Take 1000g of dimethyldichlorosilane hydrolyzate (Shandong Dongyue Organic Silicon Material Co., Ltd.), whose viscosity is tested to be 31mPa·s, add 0.5wt% 4A molecular sieve (Nanjing Jumao Technology Co., Ltd.) and dry for 8h Afterwards, the hydrolyzate obtained by filtration was clear and transparent. Transfer the hydrolyzate to a round-bottomed flask, install a 30cm long thorn type fractionation column on the round-bottom flask, heat the hydrolyzate to 100°C to remove the rings under reduced pressure, and the total rings of the received rings (D 3 ~D 8 ) content was measured on gas chromatography to reach 99.988%, of which the total chlorine content was 0.3ppm. The product remaining in the round bottom flask has a viscosity of 71.2mPa·s, a total chlorine content of 0.9ppm, and a volatile matter of 2.7%, which is low-viscosity ...

Embodiment 2

[0035] Embodiment 2: The method for preparing medium and high viscosity α, ω-dihydroxypolydimethylsiloxane, the steps are as follows:

[0036](1) Dihydroxypolydimethylsiloxane was prepared by using dimethyldichlorosilane hydrolyzate, as in step (1) of Example 1, except that the added drying reagent was changed to anhydrous calcium chloride.

[0037] (2) Take 500g of dihydroxypolydimethylsiloxane at 71.2mPa·s and put it into a round bottom flask, reduce the pressure to -0.090MPa, rapidly raise the temperature to 180°C, observe the online viscosity change on the stirrer, 1 hour 20 When the viscosity reaches 8000mPa·s within 1 minute, stop heating immediately and add 30g of carbon dioxide dry ice to rapidly cool it down to 120°C, and then take a sample for analysis. The product has a viscosity of 8800mPa·s, a total chlorine content of 0.9ppm, a volatile matter of 2.5%, and a yield of 98.1%. .

Embodiment 3

[0038] Embodiment 3: the method for preparing medium and high viscosity α, ω-dihydroxy polydimethylsiloxane, the steps are as follows:

[0039] Take dihydroxypolydimethylsiloxane with a viscosity of 22.5mPa·s, depressurize it to -0.080MPa, raise the temperature to 180°C, observe the online viscosity change on the stirrer, stop heating immediately when the viscosity reaches 1400mPa·s after 40 minutes And add 25g of carbon dioxide dry ice to make it cool down to 100°C rapidly, and then take a sample analysis, the product has a viscosity of 1520mPa·s, a volatile matter of 2.7%, and a yield of 92.2%.

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Abstract

The invention relates to a preparation method of medium / high-viscosity alpha,omega-dihydroxypolydimethylsiloxane, which comprises the following steps: heating low-viscosity dihydroxypolydimethylsiloxane to 160-250 DEG C under reduced pressure of -0.1 to -0.05MPa, stirring, and immediately cooling to finish the reaction when the product viscosity achieves the preset value, thereby obtaining the medium / high-viscosity alpha,omega-dihydroxypolydimethylsiloxane. The method provided by the invention does not use any catalyst or neutralizer in the reaction process, and does not need filtration, and the product yield is high; the invention has the advantages of short time and high production efficiency in the whole preparation process; the molecular weight distribution of the product is narrow; and the content of alkali metal ions in the product is very low.

Description

technical field [0001] The invention relates to a method for preparing medium-high viscosity α, ω-dihydroxy polydimethylsiloxane, which belongs to the technical field of organic compound preparation. Background technique [0002] α,ω-Dihydroxypolydimethylsiloxane is a kind of silicone base polymer widely used, mainly used in silicone rubber structure control agent, fabric, paper, leather material softener, anti-adhesive treatment agent, in addition It can be applied to the grafting or modification of organosilicon compounds, and the medium to high viscosity products are the base polymers of condensation type room temperature vulcanizing silicone rubber. [0003] Preparation method of low-viscosity dihydroxy polydimethylsiloxane Huang Wei (Synthesis of low-viscosity terminal hydroxyl silicone oil Huang Wei 2002 Eleventh China Organic Silicon Academic Exchange Conference Paper) and Qi Fan (hydroxyl silicone oil preparation technology Research Progress Qi Fan, Li Meijiang, et ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/16C08G77/06
Inventor 桑圣凯胡生祥伊港付佃亮张停宋超
Owner SHANDONG DONGYUE ORGANIC SILICON MATERIAL
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