High-efficiency cracking recovery method for silicone rubber waste

A silicon rubber waste and recycling method technology, applied in the field of materials, can solve the problems of increased process difficulty, large acid dosage, high process temperature, etc., and achieves the effects of improving cracking efficiency, less basic catalyst, and lowering process temperature.

Active Publication Date: 2020-04-21
GUANGZHOU BAIYUN CHEM IND
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

The high consumption of silicone rubber will inevitably bring a lot of waste silicone rubber. If it is not recycled, it will cause waste of resources and serious environmental pollution.
[0003] At present, the acid cracking process is mainly used in China, which consumes a large amount of acid, and the waste acid is not easy to handle, causing secondary pollution and resulting in high cost of acid cracking
In terms of process, the acid will cause the waste rubber powder to be suspended, which will increase the difficulty of the process
In the currently used alkaline cracking process, the initial cracking process of silicone rubber requires a higher process temperature, greater energy consumption, and a larger amount of basic catalysts required. It is reported that 1 ton of crude DMC is produced (Dimethylsiloxane mixed ring body) needs to consume 400-500kg of KOH; second, there is a high risk, and local violent reactions are prone to occur in the reactor, which may cause combustion and explosion accidents

Method used

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  • High-efficiency cracking recovery method for silicone rubber waste
  • High-efficiency cracking recovery method for silicone rubber waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] (1) Crushing: Wash the waste dimethyl silicone rubber, cut into pieces, and dry it. After cleaning the surface impurities by ultrasonic or mechanical vibration, the waste silicone rubber is crushed into particles by a rubber crusher, with a particle size of 1-2mm;

[0043] (2) Double cracking: Put the crushed silicone rubber particles into the cracking reactor, then add phenyl ether solvent and the copper complex of 5% sodium hydroxide and 0.3% of the weight of sodium hydroxide to the weight of the silicone rubber Depolymerization was carried out at a high temperature of 150°C under a nitrogen atmosphere for 3 hours to obtain crude DMC with a cracked product content of 79%;

[0044] (3) Polymerization rearrangement: Add the crude DMC to the rearrangement reactor, then add a potassium hydroxide-methanol solution with a concentration of 1%, the amount is 15% of the crude DMC mass, and 1% of the crude DMC mass Chlorotrimethylsilane was reacted at 110°C and under vacuum con...

Embodiment 2

[0047] (1) Crushing: Wash the waste dimethyl silicone rubber, cut into pieces, and dry it. After cleaning the surface impurities by ultrasonic or mechanical vibration, the waste silicone rubber is crushed into particles by a rubber crusher, with a particle size of 1-3mm;

[0048] (2) Double cracking: put the crushed silicone rubber particles into the cracking reactor, then add tetraethylene glycol dimethyl ether solvent and sodium hydroxide in an amount of 5% of the weight of the silicone rubber, and 0.5% of the weight of the sodium hydroxide. Copper complexes of Kufine base were depolymerized at a high temperature of 170° C. under a nitrogen atmosphere for 3.5 hours to obtain crude DMC with a cleavage product content of 82%;

[0049] (3) Polymerization rearrangement: Add the crude DMC to the rearrangement reactor, then add a potassium hydroxide-methanol solution with a concentration of 1%, the amount is 15% of the crude DMC mass, and 1.5% of the crude DMC mass Chlorotrimethyl...

Embodiment 3

[0052] (1) Crushing: Wash the waste dimethyl silicone rubber, cut into pieces, and dry it. After cleaning the surface impurities by ultrasonic or mechanical vibration, the waste silicone rubber is crushed into particles by a rubber crusher, with a particle size of 2-3mm;

[0053] (2) Double cracking: Put the crushed silicon rubber particles into the cracking reactor, then add phenyl ether solvent and the nickel compound of 5% sodium hydroxide and 0.4% of the weight of sodium hydroxide for the weight of the silicone rubber Depolymerization was carried out at a high temperature of 190°C under a nitrogen atmosphere for 5 hours to obtain crude DMC with a cracked product content of 79%;

[0054] (3) Polymerization rearrangement: Add the crude DMC to the rearrangement reactor, then add a potassium hydroxide-methanol solution with a concentration of 1%, the amount is 15% of the crude DMC mass, and 1.5% of the crude DMC mass Dimethyldichlorosilane was reacted at 110°C and under vacuum...

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Abstract

The invention relates to a cracking recovery method of silicone rubber waste. The method comprises the following steps: crushing of the silicone rubber waste; double cracking: putting crushed siliconerubber particles into a cracking reaction kettle, then adding a high-temperature-resistant inert solvent, alkali metal hydroxide and a Schiff base metal complex, and carrying out depolymerization ata high temperature of 140-200 DEG C in a nitrogen atmosphere to obtain crude DMC, wherein the usage amount of the alkali metal hydroxide is 5-8% of the weight of the silicone rubber waste; polymerizing and rearranging; and decolorizing and deodorizing, thereby obtaining the refined cyclosiloxane DMC. According to the cracking recovery method of the silicone rubber waste, double cracking and polymerizing and rearranging are organically combined and reasonably arranged, so the method has the advantages of low use of basic catalyst in recovery, high waste silicone rubber recovery efficiency, litter generated waste and accordance with circular economy.

Description

technical field [0001] The invention belongs to the field of materials, in particular to a high-efficiency cracking and recycling method for silicon rubber waste. Background technique [0002] With the development of industrial production, transportation, urban construction and the increase of population density, the problems of noise pollution, air pollution, water pollution and solid waste discharge have become increasingly serious, and have been listed as the four major pollutions in the world. Silicone rubber is a synthetic rubber with silicon-oxygen bonds as the main chain. Silicone rubber has excellent heat resistance, cold resistance, dielectric properties, ozone resistance and aging resistance. It is widely used in aerospace, electronics, light industry , chemical industry, textile, machinery, construction, agriculture, transportation, medical and health and other fields. Silicone rubber products are mainly divided into three categories: high temperature rubber, roo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J11/16C08J11/28C07F7/21C08L83/04
CPCC08J11/16C08J11/28C07F7/21C08J2383/04Y02W30/62
Inventor 余旭蒋金博曾容龙飞黄恒超
Owner GUANGZHOU BAIYUN CHEM IND
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