Method for reducing grain size of AC foaming agent

A foaming agent and particle size technology, applied in chemical instruments and methods, preparation of organic compounds, preparation of urea derivatives, etc., can solve problems affecting the quality of foam products, yellowing of the surface of foam products, and affecting the quality of foaming , to achieve the effect of reducing foaming temperature, reducing corrosion and improving utilization rate

Inactive Publication Date: 2010-09-22
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the particle size of the AC foaming agent currently produced is too large and the distribution is too wide, usually 20-52 μm. In the production of foam plastics, the particle size of th...

Method used

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  • Method for reducing grain size of AC foaming agent
  • Method for reducing grain size of AC foaming agent
  • Method for reducing grain size of AC foaming agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 2

[0035] 1. Synthetic biurea

[0036] Mix 15g (0.255mol) of hydrazine hydrate and a certain amount of water into a 60% (mass fraction) hydrazine hydrate aqueous solution, add it to a 250ml round bottom flask, add hydrazine hydrate and urea in a certain ratio, and then add reaction catalyst A, The amount added is 1% of the amount of hydrazine hydrate. Condense under heating conditions for 6 hours, and the reaction temperature is 106°C. When the hydrazine content in the solution is less than 0.1g / L, the reaction reaches the end. The reaction solution is cooled to room temperature, filtered, and the biurea is washed repeatedly with water to remove NH 4 OH, dry. The purity of the product biurea is not less than 98%, the melting point is 253-256°C, and the yield (calculated as hydrazine hydrate) is 95%. The ammonia gas generated by the reaction can be recovered (CN1580677, CN1393405, CN1381442, CN86104483) or passed to the Raschig process to generate hydrazine hydrate.

[0037] The abov...

Embodiment 3

[0046] 1. Synthetic biurea

[0047] Mix 15g (0.255mol) of hydrazine hydrate and a certain amount of water into a 60% (mass fraction) hydrazine hydrate aqueous solution, add it to a 250ml round bottom flask, add hydrazine hydrate and urea in a certain ratio, and then add reaction catalyst A, The amount added is 1% of the amount of hydrazine hydrate. Condense under heating conditions for 6 hours, and the reaction temperature is 110℃. When the hydrazine content in the solution is less than 0.1g / L, the reaction reaches the end. The reaction solution is cooled to room temperature, filtered, and the biurea is washed repeatedly with water to remove NH 4 OH, dry. The purity of the product biurea is not less than 98%, the melting point is 253-256°C, and the yield (calculated as hydrazine hydrate) is 95%. The ammonia gas generated by the reaction can be recovered (CN1580677, CN1393405, CN1381442, CN86104483) or passed to the Raschig process to generate hydrazine hydrate.

[0048] The above...

Embodiment 4

[0057] 1. Synthetic biurea

[0058] Mix 15g (0.255mol) of hydrazine hydrate and a certain amount of water into a 60% (mass fraction) hydrazine hydrate aqueous solution, add it to a 250ml round bottom flask, add hydrazine hydrate and urea in a certain ratio, and then add reaction catalyst A, The amount added is 1% of the amount of hydrazine hydrate. Condense under heating conditions for 6 hours, the reaction temperature is 100 ℃, when the hydrazine content in the solution is less than 0.1g / L, the reaction reaches the end, the reaction solution is cooled to room temperature, filtered, and the biurea is washed repeatedly with water to remove NH 4 OH, dry. The purity of the product biurea is not less than 98%, the melting point is 253-256°C, and the yield (calculated as hydrazine hydrate) is 95%. The ammonia gas generated by the reaction can be recovered (CN1580677, CN1393405, CN1381442, CN86104483) or passed to the Raschig process to generate hydrazine hydrate.

[0059] The above re...

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Abstract

The invention relates to a method for effectively reducing the grain size of an AC foaming agent. In the invention, hydrazine hydrate and urea are used as raw materials, an alkaline method is used for synthesizing biurea which is the intermediate of the AC foaming agent, and the biurea is oxidized to form the AC foaming agent. In the method, the biurea is formed by using the alkaline method, a mother solution is used constantly and circularly to reduce the grain size of the biurea to make the oxidation reaction more complete, and a certain amount of solution of dimethyl sulfoxide or N,N-dimethylformamide is added during the oxidation reaction to control the grain size of the AC foaming agent. Due to the circular use of the washing and filtering water and the addition of amount of the solution of the dimethyl sulfoxide or N,N-dimethylformamide during the oxidation reaction, the produced AC foaming agent has the characteristics of fine and uniform grain size, light equipment corrosion, a little amount of waste water, and environmental friendliness.

Description

Technical field [0001] The present invention relates to a method for reducing the particle size of AC blowing agent, which can reduce the particle size of AC blowing agent during the preparation process. Background technique [0002] The chemical name of AC blowing agent is azodicarbonamide, which is an organic fine chemical product. It has a large amount of gas, no pollution to products, non-toxic gas generated, no corrosion to molds, easy temperature control, and does not affect curing or Features such as molding speed. Mainly used as polyvinyl chloride, polyethylene, polypropylene, polystyrene, ethylene-vinyl acetate copolymer, ABS resin, nylon-6 and neoprene rubber, natural rubber, butyl rubber, styrene butadiene rubber and silicone rubber, etc. Foaming agent, both normal pressure foaming and pressure foaming can be used. However, the particle size of the AC blowing agent produced today is too large and the distribution is too wide, usually 20-52μm. In the production of foa...

Claims

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Application Information

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IPC IPC(8): C07C281/20C07C273/18
Inventor 吴范宏赵敏葛青邓东华牛德良水声霞熊英
Owner EAST CHINA UNIV OF SCI & TECH
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