Thermoplastic elastomer (TPE) physically-foamed roll and semi-continuous preparation method thereof

A semi-continuous preparation method of a thermoplastic elastomer (TPE) physically-foamed roll, comprising the following steps:

• (1) sequentially drying and premixing a TPE and additives, and subjecting a resulting mixture to continuous extrusion with a twin-screw extruder, calendering, and winding to obtain a precursor TPE roll;
• (2) impregnating the precursor TPE roll obtained in step (1) in a high-pressure fluid to obtain an impregnated TPE roll, and subjecting the impregnating TPE roll to a quick freezing and gas-locking treatment and low-temperature storage, wherein a mass content of the high-pressure fluid in the impregnated TPE roll is 1% to 15%;
• the quick freezing and gas-locking treatment is conducted at −20° C. to −100° C.;
• the low-temperature storage is conducted at −60° C. to −20° C.;
• and the high-pressure fluid for the impregnating comprises at least one selected from the group consisting of a CO2 fluid and a N2 fluid;
• and
• (3) heating an impregnated TPE roll obtained after the low-temperature storage in a heating medium for physical foaming, and roll pressing, cooling, and winding a foamed material to obtain the TPE physically-foamed roll, wherein the heating medium is hot air or hot water;
• wherein in step (1), the precursor TPE roll further comprises a gas blocking layer, and a preparation method of the precursor TPE roll comprises:
• sequentially drying and premixing the TPE and the additives, and subjecting a resulting mixture to continuous extrusion with a twin-screw extruder and calendering;
• and coating a surface of the elastomer with a PVA-containing aqueous solution, and drying and winding a resulting material to obtain the precursor TPE roll;
• the gas blocking layer has a thickness of 0.01 mm to 0.05 mm;
• and a mass content of PVA in the PVA-containing aqueous solution is 5% to 30%;
• in step (2), the high-pressure fluid for the impregnation has a pressure of 1 MPa to 7 MPa, and the impregnation is conducted for 1 h to 24 h.