Urethane foam molded product and method for producing the same
The present invention provides a urethane foam molded product that has high thermal conductivity with minimal change to its physical properties. A simple method for producing the same is also provided. The urethane foam molded product includes a base material formed of a polyurethane foam, and a thermal conductive filler mixed in the base material and oriented to form mutual connections. The thermal conductive filler is formed of composite particles that include thermal conductive particles formed of a nonmagnetic material, and magnetic particles adhered to the surfaces of the thermal conductive particles. The method for producing the urethane foam molded product includes a raw material mixing process that mixes a foam urethane resin material and the thermal conductive filler to obtain a mixed raw material, and a foam molding process that injects the mixed raw material into a cavity of a foaming die and performs foam molding while a magnetic field is applied so as to substantially uniform a magnetic flux density inside the cavity.
1. A urethane foam molded product, characterized by comprising a base material formed of a polyurethane, and a thermal conductive filler mixed in the base material and oriented to form mutual connections, wherein
the thermal conductive filler is formed of a composite particle, the composite particle including a thermal conductive particle formed of a nonmagnetic material, and a magnetic particle adhered to a surface of the thermal conductive particle by a water-based binder.
2. The urethane foam molded product according to claim 1 , wherein the magnetic particle is shaped as a flake.
3. The urethane foam molded product according to claim 1 , wherein the magnetic particle is formed of at least one material selected from the group consisting of iron, nickel, cobalt, and an iron-based alloy thereof.
4. The urethane foam molded product according to claim 1 , wherein an average particle size of the magnetic particle is 1 μm or more.
5. The urethane foam molded product according to claim 1 , wherein an average particle size of the thermal conductive particle is 500 μm or less.
6. The urethane foam molded product according to claim 1 , wherein the composite particle is produced according to an agitation granulation method, and
the thermal conductive particle and the magnetic particle are adhered to each other by a binder.
7. The urethane foam molded product according to claim 1 , wherein the thermal conductive particle is formed of graphite.
8. The urethane foam molded product according to claim 7 , wherein a volume ratio of the graphite to the magnetic particle in the composite particle is 7:3 to 5:5.
9. The urethane foam molded product according to claim 1 , wherein the thermal conductive particle includes an expanded graphite particle.
10. The urethane foam molded product according to claim 9 , wherein the thermal conductive particle further includes a graphite particle other than expanded graphite.
11. The urethane foam molded product according to claim 9 , wherein the expanded graphite particle is included in an amount of 5 mass % or more when a total mass of the urethane foam molded product is 100 mass %.
12. The urethane foam molded product according to claim 1 , wherein a surface of the composite particle is covered by an insulating layer.
13. A method for producing the urethane foam molded product according to claim 1 , characterized by comprising:
a raw material mixing process that mixes a foam urethane resin material and a thermal conductive filler to obtain a mixed raw material; and
a foam molding process that injects the mixed raw material into a cavity of a foaming die and performs foam molding while a magnetic field is applied so as to substantially uniform a magnetic flux density inside the cavity.