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A high-efficiency pyrolysis recovery method for silicone rubber waste

A technology of silicone rubber waste and recycling method, 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: 2022-06-07
GUANGZHOU BAIYUN CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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  • A high-efficiency pyrolysis recovery method for silicone rubber waste
  • A high-efficiency pyrolysis recovery method for silicone rubber waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] (1) pulverization: the dimethyl silicone rubber waste is washed, cut into pieces, and dried, and after the surface impurities are cleaned by ultrasonic or mechanical vibration, the silicone rubber waste is pulverized into particles by a rubber crusher, and the particle size is 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 0.3% of sodium hydroxide by weight of silicone rubber and 0.3% by weight of sodium hydroxide by adding phenyl ether solvent Depolymerization was carried out at a high temperature of 150 °C under a nitrogen atmosphere for 3 h to obtain crude DMC with a content of 79% cracked products;

[0044] (3) polymerization rearrangement: the crude DMC is added to the rearrangement reactor, then the potassium hydroxide-methanol solution that the concentration is 1% is added, and the consumption is 15% of the crude DMC quality, and 1% of the crude DMC q...

Embodiment 2

[0047] (1) pulverization: the dimethyl silicone rubber waste is washed, cut into pieces, and dried, and after ultrasonic or mechanical vibration cleaning the surface impurities, the silicone rubber waste is pulverized into particles by a rubber crusher, and the particle size is 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 with an amount of 5% by weight of silicone rubber and 0.5% by weight of sodium hydroxide Depolymerization of the copper complex of fern base was carried out at a high temperature of 170 °C under nitrogen atmosphere for 3.5 h, to obtain crude DMC with a content of cracked products of 82%;

[0049] (3) polymerization rearrangement: the crude DMC is added to the rearrangement reactor, then the potassium hydroxide-methanol solution that the concentration is 1% is added, and the consumption is 15% of the crude DMC quality, and 1.5% ...

Embodiment 3

[0052] (1) pulverization: the dimethyl silicone rubber waste is washed, cut into pieces, and dried, and after ultrasonic or mechanical vibration cleaning the surface impurities, the silicone rubber waste is pulverized into particles by a rubber crusher, and the particle size is 2-3mm;

[0053] (2) double cracking: put the crushed silicone rubber particles into the cracking reactor, then add phenyl ether solvent and the amount of sodium hydroxide that is 5% of the weight of the silicone rubber, 0.4% of the weight of the sodium hydroxide, the nickel coordination of the Schiff base Depolymerization was carried out at a high temperature of 190 °C under nitrogen atmosphere for 5 h to obtain crude DMC with a content of 79% cracked products;

[0054] (3) polymerization rearrangement: the crude DMC is added to the rearrangement reactor, then the potassium hydroxide-methanol solution that the concentration is 1% is added, and the consumption is 15% of the crude DMC quality, and 1.5% of ...

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Abstract

The invention relates to a method for cracking and recovering silicon rubber waste, which comprises the following steps: crushing the silicon rubber waste; double cracking: putting the crushed silicon rubber particles into a cracking reaction kettle, and then adding a high-temperature-resistant inert solvent and an alkali metal hydroxide , Schiff alkali metal complexes, depolymerization at a high temperature of 140-200°C under a nitrogen atmosphere to obtain crude DMC; the amount of the alkali metal hydroxide is 5%-8% of the weight of the silicone rubber waste; polymerization rearrangement ; Decolorization and deodorization to obtain refined cyclosiloxane DMC. The cracking recovery method of silicone rubber waste organically connects double cracking and polymerization rearrangement, and rationally arranges, so that less alkaline catalysts are used in recovery, waste silicone rubber recovery efficiency is higher, and waste generated is less, which meets the requirements of The advantages of a circular economy.

Description

technical field [0001] The invention belongs to the field of materials, and in particular relates to a high-efficiency pyrolysis recovery method of 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 are becoming more and more serious, and it has been listed as the four major pollutants in the world. Silicone rubber is a synthetic rubber with a silicon-oxygen bond as the main chain. Silicone rubber has excellent heat resistance, cold resistance, dielectric properties, ozone resistance and aging resistance, and is widely used in aerospace, electrical and electronic, light industry , chemical, textile, machinery, construction, agriculture, transportation, medical and health and other fields. Silicone rubber products are mainly divided into three categories: high tempe...

Claims

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Application Information

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Patent Type & Authority Patents(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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