A kind of cross-linked polyvinyl chloride structural foam material and preparation method thereof

Abstract

The invention provides a method for preparing a cross-linked polyvinyl chloride structural foam material with a physical foaming agent, comprising: melting and mixing polyvinyl chloride resin, modified resin, isocyanate, acid anhydride, nucleating agent and heat stabilizer to obtain a blank ; soaking the blank in the foaming gas for foaming to obtain a foam; cross-linking and curing the foam to obtain a cross-linked polyvinyl chloride structural foam material. The invention adopts a new process route to prepare cross-linked polyvinyl chloride structural foam, and the composition and proportion of PVC resin and other raw materials can be adjusted in a large range; the invention uses carbon dioxide or nitrogen to foam, which can make the PVC foam preparation process safer and more environmentally friendly, and can Cost reduction; the foam material prepared by the invention has a high glass transition temperature and good heat resistance; the preparation process of the invention improves the compatibility or mutual solubility of PVC and other raw materials, and the material performance is better. The invention also provides a cross-linked polyvinyl chloride structural foam material.

Description

technical field [0001] The invention belongs to the technical field of foam materials, and in particular relates to a cross-linked polyvinyl chloride structural foam material and a preparation method thereof. Background technique [0002] Foam sandwich structure composite material is a sandwich structure material that uses resin-based composite material as the skin and polymer foam as the core material. Because of its high strength, light weight, high rigidity, corrosion resistance, electrical insulation, microwave permeability It is more and more widely used in special-shaped parts such as missile wings, helicopter sidewall panels, and wind rotor blades in the aerospace industry due to its excellent characteristics. The foam core materials currently used as sandwich structures mainly include cross-linked polyvinyl chloride (PVC) structural foam, polystyrene (PS), polyurethane (PUF), acrylonitrile-styrene (SAN), polyetherimide (PEI) and polymethacrylimide (PMI) and other fo...

AI Technical Summary

Problems solved by technology

Although low-boiling organic small molecules such as cyclopentane can be used as blowing agents to replace azobisisobutyronitrile to prepare cross-linked PVC structural foams, or add expanded microspheres in the formula to reduce the amount of AIBN and the foaming pressure; but for Foaming process requirements are still high

[0005] Azodicarbonamide (AC) is generally used as a nucleating agent in the preparation of cross-linked polyvinyl chloride structural foam in the prior art, but the nucleating agent will remain in the system, which does not meet environmental protection requirements, and sodium bicarbonate and potassium bicarbonate are used Instead of AC, it is impossible to achieve a good dispersion of the nucleating agent in the system, which will eventually affect the nucleating efficiency of the nucleating agent and the uniformity of the cell structure

[0006] In the prior art, when preparing cross-linked polyvinyl chloride structural foam, it is required that the mixed material be heated to 170-175°C in the mold, and keep enough time to complete the plasticization of the core material of the mold, and then lower it to room temperature to open the mold. In actual production There is a process of repeated heating and cooling in the system, which consumes a lot of energy, and the high temperature for a long time puts forward higher requirements on the thermal stability of the system, which limits the adjustment of the formula

In addition, when the mixture is heated in the mold, only the liquid component penetrates into the PVC resin particles, so the degree of fusion between the components will be limited, which will affect the final performance of the material

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