Carrier for fluid treatment and method of making the same

A carrier for fluid treatment comprising:

• a foam containing 30 to 95% by weight of a polyolefin-based resin, 4 to 69% by weight of a cellulose-based powdery hydrophilizing agent, and 1 to 30% by weight of an inorganic powder, the surface of the foam being in a melt fractured state having a specific surface area ratio represented by the following formula (1):
• B/A=1.5 to 4.0 (1),
• where A represents the apparent specific surface area of the foam, and B represents the specific surface area of the foam, wherein
• the hydrophilizing agent is exposed at or projecting from the surface of the foam, and;
• the polyolefin-based resin is a composition having a melt flow index of 5 to 25 g/10 min.

A method of making a carrier for fluid treatment, comprising steps of:

• charging a foaming agent,
• and charging a primary blend, which has been prepared by kneading 30 to 95% by weight of a polyolefin-based resin and 5 to 70% by weight of a hydrophilizing agent composed of a cellulose-based powder,
• in a melt stirrer at a temperature not lower than the melting point of the polyolefin-based resin, followed by pulverization,
• or in a multiscrew extruder at a temperature not lower than the melting point of the polyolefin-based resin, followed by pelletization,
• into a single screw or multiscrew extruder, kneading them,
• extrusion-foaming the kneaded mass in water, and then cutting the foamed mass with an underwater pelletizer,
• or extrusion-foaming the kneaded mass in a vapor phase, and then hot cutting the foamed mass,
• to obtain a foam,
• the surface of the foam being in a melt fractured state having a specific surface area ratio represented by the following formula (1):
• B/A=1.5 to 4.0 (1),
• where A represents the apparent specific surface area of the foam, and B represents the specific surface area of the foam, wherein
• the hydrophilizing agent is exposed at or projecting from the surface of the foam, and;
• the polyolefin-based resin is a composition having a melt flow index of 5 to 25 g/10 min.

A method of making a carrier for fluid treatment, comprising steps of:

• charging a foaming agent,
• and charging a primary blend, which has been prepared by kneading 30 to 95% by weight of a polyolefin-based resin, 4 to 69% by weight of a hydrophilizing agent composed of a cellulose-based powder, and 1 to 30% by weight of an inorganic powder
• in a melt stirrer at a temperature not lower than the melting point of the polyolefin-based resin, followed by pulverization,
• or in a multiscrew extruder at a temperature not lower than the melting point of the polyolefin-based resin, followed by pelletization,
• into a single screw or multiscrew extruder, kneading them,
• extrusion-foaming the kneaded mass in water, and then cutting the foamed mass with an underwater-pelletizer,
• or extrusion-foaming the kneaded mass in a vapor phase, and then hot cutting the foamed mass,
• to obtain a foam,
• the surface of the foam being in a melt fractured state having a specific surface area ratio represented by the following formula (1):
• B/A=1.5 to 4.0 (1),
• where A represents the apparent specific surface area of the foam, and B represents the specific surface area of the foam, wherein
• the hydrophilizing agent is exposed at or projecting from the surface of the foam, and;
• the polyolefin-based resin is a composition having a melt flow index of 5 to 25 g/10 min.

A method of making a carrier for fluid treatment, comprising steps of:

• charging 30 to 95% by weight of a polyolefin-based resin, 5 to 70% by weight of a hydrophilizing agent composed of a cellulose-based powder, and a foaming agent,
• or optionally charging 30 to 95% by weight of a polyolefin-based resin, 4 to 69% by weight of a hydrophilizing agent composed of a cellulose-based powder, 1 to 30% by weight of an inorganic powder and a foaming agent,
• into a multiscrew extruder and kneading them at a temperature not lower than the melting point of the polyolefin-based resin,
• extrusion-foaming the kneaded mass in water, and then cutting the foamed mass with an underwater pelletizer,
• or extrusion-foaming the kneaded mass in a vapor phase, and then hot cutting the foamed mass,
• to obtain a foam,
• the surface of the foam being in a melt fractured state having a specific surface area ratio represented by the following formula (1):
• B/A=1.5 to 4.0 (1),
• where A represents the apparent specific surface area of the foam, and B represents the specific surface area of the foam, wherein
• the hydrophilizing agent is exposed at or projecting from the surface of the foam, and;
• the polyolefin-based resin is a composition having a melt flow index of 5 to 25 g/10 min.