Mixing method for preparing nitrile rubber/polyvinyl chloride alloy rubber compound through two-stage mixing

Abstract

The invention discloses a mixing method for preparing nitrile rubber / polyvinyl chloride alloy mixed rubber by two-stage mixing. The method is characterized in that the method comprises two-stage mixing, two internal mixers are used for mixing respectively, the first stage is heating mixing, and the second stage is cooling mixing; the method specifically comprises the following steps: adding nitrile rubber, polyvinyl chloride, a PVC stabilizer and a high-temperature rubber additive into the first-stage internal mixer, controlling the rotating speed in the mixing process to be that the shear heat generation is greater than the heat dissipation, heat is generated while mixing, and discharging after the mixing temperature reaches the first-stage discharging temperature; the discharged materials are not cooled and are directly fed into the second-stage internal mixer; and a final mixing aid is added into the second-stage internal mixer at the same time, the rotating speed and the cooling condition are controlled so that the materials are cooled at a certain cooling speed while internal mixing; when the temperature of the material mixture reaches a certain temperature, the material mixture is discharged, thus completing mixing; the material mixture is added into an open mill for thinning and sheet discharging.

Description

technical field [0001] The invention relates to the technical field of rubber-plastic alloy compounded rubber preparation technology, in particular to the field of NBR / PVC alloy mixed rubber preparation technology. Background technique [0002] NBR / PVC blends are widely used in the preparation of foamed products, such as insulation boards, cushions for sporting goods, handles, etc. In this system, NBR can provide good elasticity and feel, and PVC can play the role of a skeleton in the system, making the entire foaming system easy to operate and stable in product quality; in addition, both NBR and PVC are highly polar. Molecular polymers have good compatibility, so their applications are becoming more and more extensive. [0003] On the other hand, PVC has a high melting point. When blending it with NBR, it needs to have a good enough dispersion effect when PVC is melted. Therefore, two methods have been adopted in the prior art. The first is to use the emulsion method PVC,...

AI Technical Summary

Problems solved by technology

[0008] In the prior art, NBR / PVC compound rubber is generally mixed by two-step method, that is, NBR and PVC are mixed at high temperature first, and after being prepared into a blended rubber, other rubber additives are added after cooling, and then mixed. Discharge after reaching a certain temperature. This method has several obvious disadvantages. First, the energy consumption of mixing is very high. The preparation of the blend requires heating up. Adding rubber additives needs to be cooled before adding, and then heating up after adding. The two heating processes consume a lot of electric energy. The second is that the cooled NBR / PVC blend rubber has a high hardness, and re-mixing will cause a large loss of equipment, especially when the PVC content in the blend rubber is high. When the ratio of PVC and NBR exceeds 1:1, the operation of this method is more difficult and the loss of equipment is greater

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