Method for preparing TPU foamed beads by continuous extrusion foaming

A technology of foaming beads and extrusion foaming, which is applied in the field of continuous extrusion foaming to prepare TPU foaming beads, which can solve the problems of environmental protection and production safety, the smell of aromatic foaming agents, and the high shrinkage rate of products, etc. question

Inactive Publication Date: 2015-03-04
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The aromatic hydrocarbon blowing agent used has odor and is extremely flammable, and there are environmental protection problems and production safety problems
In addition, due to the low melt stre

Method used

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  • Method for preparing TPU foamed beads by continuous extrusion foaming
  • Method for preparing TPU foamed beads by continuous extrusion foaming

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Mix the pickled and alcoholized nano-montmorillonite (the content is 2wt%, the organic matter content of nanomaterials is 15wt%) with TPU particles, and add the mixture to the barrel of the first extruder, and the temperature range is 160-180- The screw heating at 200-185-160°C melts the TPU particles, and the supercritical CO with a pressure of 8-30MPa 2 Injected into the end of the first extruder to spread the high pressure fluid into the polymer melt. The polymer high-pressure fluid melt is injected into the second extruder through a melt pump, and the polymer high-pressure fluid melt is gradually cooled through the second extruder with a temperature range of 160-155-150-145-140-135°C.

[0034] The cooled polymer high-pressure fluid is extruded and foamed through the die of the extruder, and the foamed strips are cut into regular-sized TPU foamed particles by the underwater granulation system. The TPU expanded particles are molded by steam compression molding equipm...

Embodiment 2

[0041] Except adding sulfonated nano-carbon black (the content is 1 wt%, and the organic matter content of the nano-material is 20 wt%), other operations are the same as in Example 1. As shown in Table 1, the cell structure of the prepared TPU expanded particles is complete and uniform, the average cell size is 230 μm, the porosity is 20%, and the density of the TPU expanded particle molded body is 0.31 g / cm 3 , The tensile strength of expanded particles is 16.8MPa, and the elongation at break is 180%. The molded body of TPU foamed particles shrinks slightly, there are few gaps between the foamed particles, and the molding effect of the sample is acceptable.

Embodiment 3

[0043] Except for the addition of sulfonated carbon nanotubes (the content is 1 wt%, and the organic matter content of the nanomaterial is 30 wt%), other operations are the same as in Example 1. As shown in Table 1, the cell structure of the prepared TPU expanded particles is complete and uniform, the average cell size is 240 μm, the porosity is 12%, and the density of the TPU expanded particle molded body is 0.21 g / cm 3 , The tensile strength of expanded particles is 14.7MPa, and the elongation at break is 210%. The TPU expanded particle molding has no obvious gaps, and the sample molding effect is good.

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Abstract

The invention discloses a method for preparing TPU (Thermoplastic Polyurethane) foamed beads by continuous extrusion foaming. The method comprises the steps of (1) mixing TPU particles with inorganic nano-particles which are organically modified, adding the mixed TPU particles into a material barrel of a first extruder, melting the TPU particles into a polymer melt by screw heating, and injecting a supercritical fluid into the tail end of the first extruder to mix the supercritical fluid with the polymer melt; (2) injecting a mixed polymer/high-pressure fluid melt into a second extruder through a melt pump, and gradually reducing the temperature of a heating area of the second extruder to obtain a polymer/supercritical fluid melt which is cooled and uniformly mixed; (3) extruding the polymer/supercritical fluid melt from an opening mold of the second extruder, and performing underwater ring cutting to obtain TPU foamed particles. According to the method, a TPU foamed particle molding body material which enables the foamed particles to be well bonded after steam molding can be quickly prepared.

Description

technical field [0001] The invention belongs to the field of thermoplastic polyurethane (TPU) micro-foaming materials, in particular to a method for preparing TPU foaming beads by continuous extrusion and foaming. Background technique [0002] TPU has excellent wear resistance, chemical corrosion resistance, high elasticity and is used in shoe materials. TPU foam material not only has the above advantages of TPU resin, but also has the advantages of light weight, softness and high resilience, so it is used in the field of new high-performance sports shoes. [0003] Patent documents WO2010 / 136398A, CN102229709A, CN103642200A, and CN103951965A disclose a method for preparing TPU foaming materials by using a physical foaming agent through a kettle pressure or molded foaming process. The method does not use a crosslinking agent, and the prepared foaming material has Advantages of melt recyclable processing. However, this method is a batch foaming process, which has the problem...

Claims

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Application Information

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IPC IPC(8): B29B9/06C08L75/04C08K9/02C08K9/04C08K3/36C08K3/04C08K3/22C08K3/34C08K7/24
CPCB29B9/065B29C48/92B29C2948/92514B29C2948/92704C08J9/122C08J2203/06C08J2203/08C08J2205/052C08K3/04C08K3/346C08K3/36C08K7/24C08K9/02C08K9/04C08K2201/003C08L75/04
Inventor 翟文涛郑文革
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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