Method for efficiently coagulating natural latex under assistance effects of microwave fields

Abstract

The invention discloses a method for efficiently coagulating natural latex under assistance effects of microwave fields. The method includes steps of acquiring fresh latex with the thickness of 12-18mm; adding acid solution with the mass fraction of 2-10% into the fresh latex; heating the acid solution and the fresh latex by the aid of microwave at the frequency of 2000-3000 MHz until the latex is coagulated. The method has the advantages that the coagulation time is shorter than the coagulation time of the traditional acid coagulation processes by approximately 10 times, and accordingly thework efficiency can be improved; the acid usage can be reduced, accordingly, the cost can be lowered, and environmental hazards can be reduced; the tensile strength of vulcanized rubber treated by theaid of the method can reach 27 Mpa before the vulcanized rubber is aged, and is improved by 5-7 Mpa as compared with the traditional acid coagulation processes, the elongation at break can reach 850%and can be improved by approximately 100% as compared with the traditional acid coagulation processes, and the 300% stress at definite elongation can reach 1.80 MPa and can be improved by approximately 40% as compared with the traditional acid coagulation processes; the problem of low strength of existing aged vulcanized rubber as compared with the traditional acid coagulation processes further can be solved by the aid of the method.

Description

technical field [0001] The invention relates to the technical field of natural rubber processing, in particular to a method for efficiently coagulating natural rubber latex assisted by a microwave field. Background technique [0002] The coagulation of latex refers to the process of destroying the stability of latex under certain conditions. The fresh latex just discharged from the rubber tree, because the pH value is higher than the isoelectric point of the protein, the protein in the protective layer of the rubber particles is acid-ionized and anions are ionized, so the surface of the rubber particles is negatively charged, forming an electric double layer. Then, the surrounding water molecules are aligned on the surface of the colloidal particles to form a hydration film. Therefore, the method of coagulating latex mainly has two points in principle: reducing the negative charge on the surface of the colloidal particles or destroying the hydration film. [0003] The trad...

AI Technical Summary

Problems solved by technology

Coagulation with acid will cause part of the protein components in the latex to move to the skim, especially the molecules containing non-colloid substances that can promote vulcanization are dissolved in the skim, and are washed away when the rubber is rinsed, so the rubber vulcanization rate obtained Slow, low crosslink density, low vulcanizate strength

In terms of physical properties, the modulus and tensile strength of microwave coagulation vulcanizate before aging are higher than those of acid coagulation, but the modulus and tensile strength after aging are lower than those of acid coagulation

[0005] It can be seen that microwave coagulation and acid coagulation have their own advantages and disadvantages. At present, it is urgent to provide a method that can not only maintain the advantages of short microwave coagulation time, high work efficiency, and good strength of vulcanized rubber, but also solve the problem of the aging of the vulcanized rubber. low problem

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