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Method for preparing hydrogenated natural rubber by emulsion method

A technology of natural rubber and emulsion method, which is applied in the field of modified natural rubber and used in the preparation of modified natural rubber, and can solve the problems such as difficulty in obtaining high hydrogenation degree HNR.

Active Publication Date: 2018-06-29
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that it is difficult to obtain HNR with a high degree of hydrogenation in the prior art, and to provide a method for preparing hydrogenated natural rubber by an emulsion method, and the hydrogenation degree of HNR in this method can reach up to 90%.

Method used

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  • Method for preparing hydrogenated natural rubber by emulsion method
  • Method for preparing hydrogenated natural rubber by emulsion method
  • Method for preparing hydrogenated natural rubber by emulsion method

Examples

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Effect test

Embodiment 1

[0037] Add natural rubber latex to a four-neck flask equipped with a condenser, a mechanical stirrer and a thermometer, turn on the mechanical stirring paddle, heat the latex to 55°C, then add hydrazine hydrate; accurately weigh a certain amount of boric acid and dissolve it in deionized water After adding to the reaction system; add an appropriate amount of H at a constant rate 2 o 2 When the reaction system was reached, the reaction was continued for 1 hour after 7 hours of dripping, and the reaction was stopped. C=C:N in NR 2 h 4 :H 2 o 2 The molar ratio is 1:1:1, and the amount of boric acid added is 0.1M. The reactant was taken out and demulsified with 2% calcium chloride aqueous solution, the hydrogenated product was washed with deionized water, and vacuum-dried in an oven at 60°C for 24 hours to obtain HNR raw rubber with a hydrogenation degree of 17.6%.

Embodiment 2

[0039] Add natural rubber latex to a four-neck flask equipped with a condenser, a mechanical stirrer and a thermometer, turn on the mechanical stirring paddle, heat the latex to 55°C, then add hydrazine hydrate; accurately weigh a certain amount of boric acid and dissolve it in deionized water After adding to the reaction system; add an appropriate amount of H at a constant rate 2 o 2 When the reaction system was reached, the reaction was continued for 1 hour after 7 hours of dripping, and the reaction was stopped. C=C:N in NR 2 h 4 :H 2 o 2The molar ratio is 1:2:1.5, and the amount of boric acid added is 0.1M. The reactant was taken out and demulsified with 2% calcium chloride aqueous solution, the hydrogenated product was washed with deionized water, and vacuum-dried in an oven at 60°C for 24 hours to obtain HNR raw rubber with a hydrogenation degree of 34.6%.

Embodiment 3

[0041] Add natural rubber latex to a four-neck flask equipped with a condenser, a mechanical stirrer and a thermometer, turn on the mechanical stirring paddle, heat the latex to 55°C, then add hydrazine hydrate; accurately weigh a certain amount of boric acid and dissolve it in deionized water After adding to the reaction system; add an appropriate amount of H at a constant rate 2 o 2 When the reaction system was reached, the reaction was continued for 1 hour after 7 hours of dripping, and the reaction was stopped. C=C:N in NR 2 h 4 :H 2 o 2 The molar ratio is 1:3:4.5, the amount of boric acid added is 0.1M, the reactant is taken out and demulsified with 2% calcium chloride aqueous solution, the hydrogenated product is washed with deionized water, and vacuum-dried in an oven at 60°C for 24 hours to obtain a hydrogenation degree of 42.7% HNR raw rubber.

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Abstract

The invention relates to a method for preparing hydrogenated natural rubber (HNR) using an emulsion process. The method comprises the following steps: performing hydrogenation modification on natural rubber in natural latex by adopting a hydrazine hydrate / hydrogen peroxide / boric acid catalytic system; and flocculating by using an aqueous solution of 2% CaCl2 and drying, thereby obtaining the HNR with different hydrogenation degrees. According to the catalytic system, NR main chain hydrogenation can be catalyzed in an emulsion state; the gel content and decomposition temperature can be increased along with the increase of the NR hydrogenation degree, and a glass-transition temperature is slightly increased; and the crosslinking density of vulcanized rubber is increased along with the increase of the hydrogenation degree. Therefore, after hydrogenation, the flexibility of the HNR is reduced, and the thermal stability is improved; and the hydrogenation degree is increased, and the crystallization capacity of the HNR is decreased. The hydrogenation of the NR is expected to improve the aging resistance of the rubber.

Description

technical field [0001] The present invention relates to a modified natural rubber and a method for preparing the modified natural rubber, more particularly, the present invention relates to a method for modifying natural rubber by an emulsion method. Background technique [0002] As a natural green raw material, natural rubber is widely used in all walks of life. Its products have high elasticity, high elongation at break, and high mechanical stability. Because the natural rubber molecular chain contains chemically active carbon-carbon double bonds, it is easy to Under the action of heat, oxygen, ozone, light, etc., cross-linking or chain scission reactions occur, thereby affecting the performance of rubber. Therefore, people use different methods to chemically modify the molecular structure of natural rubber, such as introducing epoxy bonds (-C-O-C-) and a small amount of carbon-oxygen double bonds (-C=O) on the unsaturated double bonds of the molecular chain, to prepare E...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08C19/02
CPCC08C19/02
Inventor 张立群季美琴岳冬梅赵鑫张英东
Owner BEIJING UNIV OF CHEM TECH
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