초록 ▼

A polyolefin filter for tobacco products and the like was prepared. The extruded element is an open-cell foamed polyethylene or polypropylene having a TPM filtration efficiency greater than 20%. The filter rod can be made by extruding polyethylene containing less than 0.2 moles of a volatile blowing

A polyolefin filter for tobacco products and the like was prepared. The extruded element is an open-cell foamed polyethylene or polypropylene having a TPM filtration efficiency greater than 20%. The filter rod can be made by extruding polyethylene containing less than 0.2 moles of a volatile blowing agent per 100 grams of resin at a melt temperature between 130°C. and 150°C., the temperature of the die being between 120°C. and 136°C. Higher melt temperature and die temperature are required for polypropylenes.

대표청구항 ▼

In a process for the extrusion through a metal die of a high density polyethylene resin having a melt temperature between 130°C. and 150°C. or a polypropylene resin having a melt temperature of between 160°C. and 180°C., wherein each resin contains a volatile blowing agent in an amount less than 0.2

In a process for the extrusion through a metal die of a high density polyethylene resin having a melt temperature between 130°C. and 150°C. or a polypropylene resin having a melt temperature of between 160°C. and 180°C., wherein each resin contains a volatile blowing agent in an amount less than 0.2 moles per 100 grams of the final extruded resin, the improvement which comprises maintaining the temperature of the die within 5 millimeters of the metal-resin interface at a temperature of between 120°C. and 136°C. where the resin is polyethylene and between 155°C. and 165°C. where the resin is polypropylene.