A thermoplastic polyurethane elastomer foam material with density gradient and preparation method thereof

Abstract

The invention belongs to the field of polymer foaming materials, and in particular relates to a thermoplastic polyurethane elastomer foaming material with a density gradient and a preparation method thereof. The thermoplastic polyurethane elastic foaming material has an outer layer and an inner layer with no interface bonding structure , the density of the outer layer (1) is 0.8‑1.3g / cm 3 , the density of the inner layer (2) is 0.2‑0.8g / cm 3 , wherein the thickness of the outer layer (A) accounts for 2-40% of the thickness of the entire material section, and the thickness of the inner layer (1) accounts for 60-98% of the thickness of the entire material section. The thermoplastic polyurethane elastomer foaming material with a density gradient is prepared by injection molding of 90-99.9wt% thermoplastic polyurethane elastomer, 0.1-5wt% chemical foaming agent and 0-5wt% adhesive The product has the advantages of light weight, high resilience, wear resistance, excellent tensile strength, compression deformation, thermal dimensional stability and low temperature resistance.

Description

technical field [0001] The invention belongs to the field of polymer foaming materials, in particular to a thermoplastic polyurethane elastomer foaming material with a density gradient and a preparation method thereof. Background technique [0002] Thermoplastic polyurethane elastomer (TPU) is a semi-crystalline polymer material prepared by combining diisocyanate, long-chain diol and short-chain diol in a certain proportion on a belt system or in a reactive extruder. TPU has excellent mechanical properties, excellent heat resistance and chemical medium resistance, and excellent wear resistance. And due to the diversity of raw material formulations, by adjusting the ratio of each raw material, products with a very wide range of hardness can be obtained. [0003] Foaming materials are the main way to promote the lightweight development of materials. At present, the preparation methods of foaming TPU materials are mainly divided into the following methods: (1) Foaming by physi...

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Problems solved by technology

[0003] Foaming materials are the main way to promote the lightweight development of materials. At present, the preparation methods of foaming TPU materials are mainly divided into the following methods: (1) Foaming by physical foaming agent, foaming by kettle pressure or extrusion foaming The foamed TPU particles are prepared by the method, and then the prepared foamed TPU particles are processed into products by steam molding equipment or adhesive molding equipment. The advantages of this method are that the prepared products have low density, good elasticity and high tensile strength. The disadvantage of this method is that the preparation process is complicated, the production stability of foamed TPU particles is poor, the cost of the resulting product is high, and the application is relatively limited.

(2) Using chemical foaming agent to prepare products by injection molding or extrusion equipment, the advantages of this method are simple preparation process, continuous production and low cost and high efficiency; the disadvantage of this method is the high density of the obtained products

However, even if the product obtained by the above method has either uneven cells and rough surface, or has relatively thick cells and has cavities

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