Manufacturing method of a 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 nuclear 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.
Claims13
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 contains 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 within the thermoplastic polyurethane resin, the method comprising:
- foaming a pellet by supercritical physical foaming by injecting a supercritical fluid into the TPU resin,
- under a temperature in a range of 120 to 180° C. to produce a foamed pellet with a specific gravity of 0.05 to 0.25;
- and
- compress-molding the foamed pellets, thereby producing a TPU shoe sole comprising hydrophobic nano-silica.
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:
- injecting a supercritical fluid into the TPU resin, by supercritical physical foaming, at a temperature of 160 to 220° C. for injection molding at a specific gravity in a range of 0.05 to 0.25, thereby forming TPU shoe sole with hydrophobic nano-silica.
A method for 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 in a range of 100 to 1,200 nm in the thermoplastic polyurethane resin, the method comprising:
- injection molding the TPU resin to form a preform;
- and
- injecting a supercritical fluid into the preform, by supercritical physical foaming, at a temperature in a range of 120 to 220° C., to produce a foamed molded foam with a specific gravity in a range of 0.05 to 0.15, thereby producing a TPU shoe sole comprising hydrophobic nano-silica.
Dependencies are inferred from the claim text.