Manufacturing method of thermoplastic polyurethane shoe-sole comprised hydrophobic nano silica by supercritical physical foaming
AssigneeSam Bu Fine Chemical Co., Ltd.
InventorHeedae PARK
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Abstract
This invention is related to a TPU shoe sole (midsole/insole) manufactured by supercritical physical foaming by incorporating hydrophobic nano-silica powder as a foaming nucleating agent to uniformly form microscopic foaming cells during the molding process, thereby achieving a soft touch, high elasticity, and comfortable fit, as well as excellent shape stability and durability, while also enabling lightweight products and reduced material costs.
Claims4
A method for manufacturing thermoplastic polyurethane (TPU) shoe soles using TPU resin composed of polyol, isocyanate, and chain extender as raw materials, wherein the TPU resin comprises hydrophobic nano-silica powder with primary particle sizes of 1 to 100 nm as a foaming nuclear agent in a range of 0.1 to 5 parts per hundred resin (phr), the hydrophobic nano-silica powder forms nano-silica aggregates with an average size of 100 to 1,200 nm in the TPU resin, the method comprising:
- foaming a pellet by supercritical physical foaming by injecting a supercritical
- fluid into the TPU resin at a temperature range of 160 to 220° C. for injection molding at a specific gravity in a range of 0.05 to 0.25 to produce a foamed pellet;
- and compress-molding the foamed pellet, thereby forming TPU shoe sole with hydrophobic nano-silica.
Dependencies are inferred from the claim text.