Method for chemical removal of residual monomer in rubber latex

A technology for rubber latex and residual monomers, applied in the field of chemical removal of residual monomers in rubber latex, to achieve the effects of less rubber impurity content, less equipment investment, and reduced production costs

Active Publication Date: 2013-05-29
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] At present, there is no method that adopts the form of chain chemical reaction to realize the removal or utilization of residual monomers in emulsion polymerization.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Powdered Nitrile Rubber Special Latex

[0033] at 3M 3 225 kilograms of emulsifier aqueous phase (potassium stearate and potassium oleate aqueous emulsion) and reaction monomer oil phase (800 liters of butadiene and 380 liters of acrylonitrile) of latex formula amount in the polymerization kettle, add persulfuric acid under vacuum 80 kg of potassium aqueous solution was reacted at 40°C for 12 to 15 hours. When the monomer conversion rate reached 92% to 96%, 2.6 kg of hydrogen peroxide solution (concentration 30%) was added, and the reactor was filled with Nitrogen 0.2MPa, raised to 65°C and reacted for 2-3 hours, the monomer conversion rate can reach more than 99.5%, after cooling down to 25°C, unloading, after coagulation detection, combined acrylonitrile ≥ 38.5%, Mooney viscosity Gel 55%, tensile strength ≥ 24.5MPa, elongation at break ≥ 400%, 300% modulus ≥ 12MPa free acrylonitrile content below 50ppm, butadiene residue is zero.

Embodiment 2

[0035] Nitrile latex for impregnation

[0036] at 21M 3 The emulsifier aqueous phase (sodium lauryl sulfate aqueous emulsion) 2.59M of latex formulation amount in the polymerization kettle 3 And reactive monomer oil phase (butadiene 4.3M 3 , Acrylonitrile 3.6M 3 , Acrylic 1.5M 3 ), add 96 kilograms of ammonium persulfate aqueous solution under vacuum, react 8~12 hours at 30 ℃, when monomer conversion ratio reaches 92%~96%, add 75.9 kilograms of ammonia solution (concentration 33%) again, Fill the reactor with nitrogen above 0.2MPa, raise the temperature to 45°C and react for 2-3 hours, the conversion rate of the monomer can reach more than 99.5%, after cooling down to 25°C and unloading, the free acrylonitrile content is detected to be below 50ppm, but Diene residues were zero.

[0037] Main physical indicators:

[0038] Total solid content ≥ 45%, acrylonitrile binding content ≥ 30%, viscosity ≤ 50mPa·s Ph7.5~9 free acrylonitrile content ≤ 50ppm

Embodiment 3

[0040] Carboxylated Nitrile Rubber Latex

[0041] .at 21M 3 The emulsifier aqueous phase (sodium lauryl sulfate aqueous emulsion 2.85M) of latex formulation amount in the polymerization kettle 3 ) and reactive monomer oil phase (butadiene 5.5M 3 , Acrylonitrile 3.2M 3 , Methacrylic acid 1.26M 3), add 96 kilograms of potassium persulfate aqueous solution under vacuum, react at 40 ℃ for 8~12 hours, when monomer conversion rate reaches 92%~96%, add 29.6 kilograms of hydrogen peroxide solution (concentration 30% ), fill the reactor with nitrogen above 0.2MPa, raise the temperature to 55°C for 2 to 3 hours, and the conversion rate of the monomer can reach more than 99.5%. , Butadiene residue is zero, combined with acrylonitrile ≥ 32.5%, tensile strength ≥ 26.8MPa, elongation at break ≥ 280%, 100% modulus stress, ≥ 9.3MPa.

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Abstract

The invention relates to a method for chemical removal of a residual monomer in rubber latex, which is characterized by comprising: heating to raise the reaction temperature when the monomer conversion rate reaches more than 85 percent during preparation of the rubber latex via emulsion polymerization of the monomer, and adding water-soluble initiators under the nitrogen pressure of 0.02-0.04MPa,wherein the best amount of the added initiator solution is 0.1-2 portion(s) while the mass of the dry latex is 100 portions. The reaction time is 1-3 hour(s). The rubber prepared in the method for removal of the residual monomer in the latex contains fewer impurities, the degassing time is short, and the production efficiency is high. The method can be applied in preparation of synthetic rubber latex containing gel, containing no gel, with high Mooney viscosity, with low Mooney viscosity and with polar groups and other types of synthetic rubber latex with high adhesiveness, and the prepared product can be applied in medical gloves, condoms, food package coating and the like.

Description

technical field [0001] The invention relates to a chemical removal method for residual monomers in rubber latex, more specifically, a method for chemically reacting residual monomers in rubber latex to achieve the purpose of removal, mainly because it is difficult to remove Some monomers that are slightly soluble in water can be reduced to less than 50ppm, which can be used in daily life such as medical care, food and packaging, rather than just for industrial purposes. Background technique [0002] At present, most of the methods for removing residual monomers in rubber latex are physical or physical-chemical methods to achieve the purpose of reducing them. [0003] Physical method: [0004] The physical sealing method refers to adding latex into a closed container under stirring conditions. The residual monomer is separated from the emulsion by increasing the temperature and reducing the vacuum degree. After the gas phase is separated, the method of condensing the liquid ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F2/26C08F2/30C08F6/14
Inventor 张元寿赵继忠龚光碧梁滔陈建刚李树毅李晶钟启林胡育林于奎桂强赵洪国郑彩琴马朋高黄铁梁孙丽琳
Owner PETROCHINA CO LTD
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