Thermoplastic polyurethane elastomer foam bead and preparation method thereof

Abstract

The invention discloses a thermoplastic polyurethane elastomer foam bead and a preparation method thereof. The method comprises the following steps: firstly, adding thermoplastic polyurethane particles and water to a reaction kettle according to the mass ratio of 1 to (0.8-4); adding liquid carbon dioxide to the reaction kettle, and controlling the intensity of pressure and the temperature in the reaction kettle, so that the carbon dioxide in the reaction kettle is in a super-critical state; raising the temperature inside the reaction kettle to 90-140 DEG C; carrying out heat preservation; putting the materials in the kettle into a pressure tank, maintaining pressure, and cooling to below 70 DEG C; foaming the thermoplastic polyurethane elastomer particles once, and controlling the volume ratio of the reaction pressure to the pressure tank to be 1 to (15-30); putting the disposable foam particles into a storage tank, and carrying out secondary normal pressure foaming to obtain thermoplastic polyurethane elastomer foam beads; and removing the surface moisture of the foam beads, and curing the foam beads at normal pressure and normal temperature for over 48 hours, so as to obtain the product. The product disclosed by the invention has the characteristics of even and compact cells, small size, high percentage of closed area, high molding product strength, good rebound resilience and the like.

Description

technical field [0001] The invention relates to a thermoplastic polyurethane elastomer, in particular to a thermoplastic polyurethane elastomer foamed bead and a preparation method thereof. Background technique [0002] Thermoplastic polyurethane elastomer (Thermoplastic polyurethane) is a new type of organic polymer synthetic material, which belongs to high molecular polymer, and can replace rubber (rubber) and soft polyvinyl chloride (pvc). There are three types of thermoplastic polyurethane elastomers: polyester type, polyether type and aliphatic, white transparent random spherical or oval particles, relative density 1.10-1.25. The outstanding features of thermoplastic polyurethane elastomers are excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low temperature resistance, good oil resistance, chemical resistance and environmental resistance. [0003] Compared with pure thermoplastic elastomer materials, thermoplastic p...

AI Technical Summary

Problems solved by technology

[0004] Chinese invention patent application CN103642200A (application number 2013107064442; application date 2013.12.20) discloses a foamed thermoplastic polyurethane bead, which contains 100 parts of thermoplastic polyurethane particles, 1-10 parts of cell size stabilizer, 1 -35 parts of melt viscosity regulator; the melt viscosity of the expanded thermoplastic polyurethane beads at 180°C is 8000-15000 poises; the diameter of the cells of the beads is 500-800 microns; The foaming agent is produced by immersing thermoplastic polyurethane particles containing a cell size stabilizer and a melt viscosity regulator in an aqueous suspension, and then foaming; foaming can only be achieved by means of a cell size stabilizer and a melt viscosity regulator , To use equipment such as screw extruders, the cost of raw materials and production costs are relatively high, and the cell size is controlled by a cell size stabilizer and a melt viscosity regulator. The diameter of the bead cells is 500-800 microns, which is difficult to reach 400 Below micron, the cell density of the foamed beads is not enough, the elasticity of the product is relatively poor, and the strength is not high enough

Images