Preparation method of thermoplastic polyurethane foam leather

Abstract

The invention discloses a preparation method of thermoplastic polyurethane foam leather. The method comprises steps as follows: 1) performing dry mixing on TPU resin, a chain extender, a gas barrier, a compatilizer and a nucleating agent; 2) adding a mixture to a barrel of an extruder, heating the mixture by the extruder to obtain TPU melt, injecting supercritical N2 into the TPU melt at the speed of 1-30 ml / min, uniformly mixing the TPU melt and the supercritical N2, gradually decreasing the temperature of the melt to 155 DEG C by a heat exchanger after mixing, and extruding the mixed melt through a slit die to obtain an expanded TPU film, wherein the temperature of the die of the extruder in the extrusion process is 140-160 DEG C and the pressure of the die of the extruder is 5-25 MPa; 3) performing drawing thinning on the TPU film by an uniaxial drawing device at the temperature of 130-160 DEG C for less than 15 s to prepare a TPU foam film, and attaching the TPU foam film to cloth at the high temperature to obtain TPU foam leather. With the adoption of the method, the defects that the TPU foam film in the TPU foam leather has higher density and larger foam are overcome.

Description

technical field [0001] The invention relates to a method for preparing thermoplastic polyurethane (TPU) foamed leather, in particular to a method for continuously preparing TPU foamed leather by physical foaming of a supercritical fluid. Background technique [0002] Artificial leather such as polyurethane (PU) foam leather, polyvinyl chloride (PVC) and other foam leather, as a substitute for natural leather, is developing rapidly in our country. However, a large amount of toxic and harmful solvents and plasticizers are inevitably used in the production and processing of artificial leather. In recent years, with the improvement of people's awareness of environmental protection, the problem of volatile organic compounds (VOC) in the use of artificial leather has attracted the attention of all walks of life and the artificial leather industry. At present, Europe, America, Japan, and China have successively introduced VOC detection regulations. [0003] TPU has many advanta...

AI Technical Summary

Problems solved by technology

Due to the extremely fast diffusion speed of the high-pressure fluid in the TPU matrix, this method is difficult to prepare foamed film materials for artificial leather with a thickness of only 0.1-0.5 mm, and can only prepare thicker insoles and other materials.

In addition, this method is a batch method, and there is a problem of low processing efficiency.

[0008] Chinese patent literature CN104385479A discloses a method for extruding foamed TPU resin with a supercritical fluid, which uses supercritical CO 2 As a foaming agent, TPU foam beads have been prepared by continuous extrusion and underwater cutting, but this method is not suitable for the preparation of TPU foam films and TPU foam leather.