A kind of graft modified natural rubber, its preparation method, rubber composition comprising graft modified natural rubber and its application

Abstract

The invention provides a grafting-modified natural rubber and a preparation method thereof. The preparation method includes: diluting natural rubber latex with a diluent, emulsifying the rubber latex,adding a grafting modifier and an acrylate monomer, and performing a grafting initiation reaction by using a redox initiator at 40-60 DEG C for 2-24 h; after the reaction is finished, successively performing demulsification, centrifugal separation, washing and drying to obtain the grafting-modified natural rubber, which has stable grafting rate, high source hardness and stress at definite elongation, is low in production temperature, is simple in production equipment and saves energy. The stress at definite elongation can replace a part of raw rubber for preparing a pneumatic tyre, particularly the side walls, tread, bead filler and side insert rubber of the pneumatic tyre. The prepared tyre is low in thermogenesis and is better in dynamic performance.

Description

technical field [0001] The invention relates to a graft modified natural rubber, a preparation method thereof, a rubber composition containing the graft modified natural rubber and its application, in particular to the application of the rubber composition in pneumatic tires. [0002] technical background [0003] For a long time, in rubber products such as tires, in view of the excellent elasticity, strength and flex resistance of natural rubber, natural rubber is usually selected as the base material. Natural rubber is a non-polar rubber, which is commonly used in rubber with carbon black and The interface bonding of fillers with surface active groups such as white carbon black is not good, and natural rubber needs to be modified to improve its properties such as wear resistance, flex resistance, wet skid resistance, and compatibility with polar fillers. Modification methods include epoxidation modification, halogenation modification, cyclization modification, hydrogenation...

AI Technical Summary

Problems solved by technology

[0004] Acrylic ester materials are grafted with natural rubber, and Tianjia rubber, an industrialized product of natural rubber grafted with methyl methacrylate, has been produced. The main brands are MG-30 and MG-49, which are currently used in the fields of adhesives and non-tire rubber products. There are many reports (such as CN105348581B, CN109401676A), but there are fewer reports on the application in tire formulations

CN105131777B reported that materials such as Tianjia rubber and coumarone resin were dissolved in a solvent to prepare a coating liquid, and the bead wire was applied to form a coating that could effectively improve the adhesion between the bead wire and the bead rubber, but it was not It is used in the formula of tire parts instead of raw rubber such as natural rubber. CN106459509B reports that methacrylate polymers are applied to the tire tread formula containing diene rubber, and the rolling resistance is unchanged while improving wet slip. However, it is a mixture of methacrylate polymer and diene rubber, not a graft modification of the two.

[0005] In addition, tires and other products need to be filled with a large amount of carbon black, white carbon black or other inorganic fillers. Products used under dynamic conditions are easy to agglomerate due to the presence of surface active groups such as carbon black or white carbon black during use. A large amount of inorganic filler is filled, which will generate a lot of heat due to the internal friction with the rubber, which will increase the heat generation, and also cause problems such as difficult processing, increased cost and long mixing time.

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