Housing parts, housings and processes for preparing the same
The present invention relates to a housing part, a housing and an electronic device. The housing part according to this invention comprises a first layer, said first layer being molded from a first composition comprising a1) 50-90 wt. % of a first amorphous polymer and b1) 10-50 wt. % of a first thermally conductive filler, the first composition having a thermal conductivity (TC1) of 4-40 W/(m*K), a second layer, said second layer being molded from a second composition comprising a2) 50-90 wt. % of a second amorphous polymer and b2) 10-50 wt. % of a second thermally conductive filler, the second composition having a thermal conductivity (TC2) of 0.5-10 W/(m*K), and the second layer being molded over the first layer by leaving at least one area of the first layer not being over-molded with the second layer for being exposed to at least one heat source, wherein, TC1 is at least 2 W/(m*K) larger than TC2, the amounts of al and b1 are based on the total weight of the first composition, the amounts of a2 and b2 are based on the total weight of the second composition, and the thermal conductivity is measured in-plane according to ASTM E1461-01. The housing part provided in this invention has high heat dissipating efficiency and mechanical properties as well as high dimensional stability.
1. A housing part comprising
a first layer, said first layer being molded from a first composition comprising a1) 50-90 wt. % of a first amorphous polymer and b1) 10-50 wt. % of a first thermally conductive filler, the first composition having a thermal conductivity (TC1) of 4-40 W/(m*K),
a second layer, said second layer being molded from a second composition comprising a2) 50-90 wt. % of a second amorphous polymer and b2) 10-50 wt. % of a second thermally conductive filler, the second composition having a thermal conductivity (TC2) of 0.5-10 W/(m*K), and the second layer being molded over the first layer by leaving at least one area of the first layer not being over-molded with the second layer for being exposed to at least one heat source,
wherein, TC1 is at least 2 W/(m*K) larger than TC2, the amounts of al and b1 are based on the total weight of the first composition, the amounts of a2 and b2 are based on the total weight of the second composition, and the thermal conductivity is measured in-plane according to ASTM E1461-01.
2. The housing part as claimed in claim 1 , wherein the first amorphous polymer and/or the second amorphous polymer is an aromatic polycarbonate.
3. The housing part as claimed in claim 1 , wherein the first composition and/or the second composition comprises less than 5 wt. % of a semi-crystalline polymer or a crystalline polymer, based on the total weight of the first composition and/or the second composition respectively.
4. The housing part as claimed in claim 1 , wherein at least 50 wt. % of b1) is selected from the group consisting of a silicon nitride, an aluminium nitride, a boron nitride, a graphite, a ceramic filler and any mixtures thereof, based on the total weight of b1).
5. The housing part as claimed in claim 1 , wherein at least 50 wt. % of b2) is selected from the group consisting of a magnesium hydroxide, a talc, a boehmite aluminum hydroxide, a diaspore aluminum hydroxide, a gibbsite aluminum hydroxide, a calcium carbonate, a mica, a barium oxide, a barium sulfate, a calcium silicate, a zirconium oxide, a silicon oxide, a glass beads, a magnesium aluminum oxide, a calcium magnesium carbonate, a ceramic coated graphite, a clay, and any mixtures thereof.
6. The housing part as claimed in claim 1 , wherein the area of the first layer not being over-molded with the second layer comprises at least one heat sink for being coupled with at least a heat source.
7. The housing part as claimed in claim 6 , wherein the heat sink comprises at least one fin.
8. The housing part as claimed in claim 6 , wherein the heat sink is coupled with the heat source through a thermal interface material.
9. A housing comprising the housing part as claimed in claim 1 .
10. The housing in claim 9 , wherein the housing further comprises a covering part coupled with the housing part for forming the housing, said covering part being made from a thermoplastic polymer.
11. An electronic device comprising the housing as claimed in claim 9 , and further comprising at least one electronic component as the heat source mounted in the housing.
12. A process for preparing the housing part as claimed in claim 1 , comprising the steps of:
molding the first layer with the first composition in a first mold cavity, and
molding the second layer with the second composition in a second mold cavity over the first layer by leaving at least one area of the first layer not being over-molded with the second layer for being exposed to at least one heat source.