COMPOSITIONS FOR AN LED REFLECTOR AND ARTICLES THEREOF
Disclosed herein is a resin composition for molding a reflector for a light-emitting semiconductor diode comprising about 25 to about 80 wt. % of an heat-resistant aromatic polyester, about 5 to 50 wt. % of titanium dioxide filler; and about 5 to 50 wt. % of a glass fibers having a flat surface. In another aspect of the present invention, there is also provided a reflector for a light-emitting semiconductor element, which includes a molded product of the resin composition. In a further aspect of the present invention, there is also provided a light-emitting semiconductor unit comprising a light-emitting semiconductor diode element, leads connecting electrodes of the light-emitting semiconductor diode element with external electrodes, respectively, and the reflector.
1 . A resin composition for molding a reflector for a light-emitting diode comprising:
about 25 to about 80 wt. % of a heat-resistant aromatic polyester having a melting point of at least 260° C. of which
at least about 80 mole percent of diol repeat units in the polyester, derivable from 1,4-cyclohexanedimethanol, are of formula (I):
and at least about 80 mole percent of dicarboxylic acid repeat units in the polyester, derivable from terephthalic acid, are of formula (II):
about 5 to 50 wt. % of white titanium dioxide filler; and
about 5 to 50 wt. % of glass fiber having a flat surface.
2 . The resin composition of claim 1 , wherein the heat-resistant aromatic polyester is selected from the group consisting of poly(1,4-cyclohexanedimethylene terephthalate), poly(1,4-cyclohexylene dimethylene terephthalate-co-isophthalate), poly(1,4-cyclohexylene dimethylene co-ethylene terephthalate), and mixtures thereof.
3 . The resin composition of claim 1 , wherein the heat-resistant aromatic polyester is poly(1,4-cyclohexanedimethylene terephthalate).
4 . The composition of claim 1 , wherein the composition comprises, in addition to the heat-resistant aromatic polyester, an organic resin selected from the group consisting of polybutylene terephthalate, polypropylene terephthalate, polyethylene terephthalate, copolyesters comprising 2,2,4,4-tetramethyl-1,3-cyclobutanediol units, nylon 6,6, polyphthalamide, copolymers of the forgoing polymers, and a combination thereof, in an amount of between 1 and 40 wt. %, based on the total weight of the composition, and 2 to 49 wt. % based on the total weight of resin in the composition.
5 . The composition of claim 6 , wherein the composition comprises, in addition to the heat-resistant aromatic polyester, an organic resin selected from the group consisting of polybutylene terephthalate, polypropylene terephthalate, and combinations thereof.
6 . The composition of claim 1 , wherein the composition further comprises a white inorganic filler selected from the group consisting of potassium titanate, zirconium oxide, zinc sulfide, zinc oxide, barium sulfate, magnesium oxide, and mixtures thereof.
7 . The composition of claim 1 , wherein the titanium dioxide has an inorganic surface treatment with alumina and an organic surface treatment with a polysiloxane compound.
8 . The composition of claim 1 , wherein at least 90 weight percent of white inorganic filler in the composition is titanium dioxide, based on the total white inorganic filler.
9 . The composition of claim 8 , wherein the composition further comprises a second inorganic filler that is not titanium dioxide.
10 . The composition of claim 1 , wherein titanium dioxide is present in an amount of 12 to 30 wt. % based on the total composition.
11 . The composition of claim 1 , wherein the glass fiber has a trapezoidal, square, or rectangular cross-section.
12 . The composition of claim 1 , wherein the glass fiber has an average aspect ratio of 1:1 to 5:1 wherein aspect ratio refers to the axial cross-section of the glass fiber.
13 . The composition of claim 1 , wherein the glass fibers, when compounded into the resin the composition, have an average length of 0.1 mm to 10 mm and an equivalent circular diameter, in cross section, of 5 to 25 micrometers.
14 . The composition of claim 1 , wherein a molded article comprising the composition has a reflectance at 460 nm of 80 to 98 percent.
15 . The composition of claim 1 , wherein a molded article comprising the composition has a reflectivity in the range from 380 nm to 750 nm of 80 to 98 percent.
16 . A resin composition for molding a reflector for a light-emitting semiconductor diode reflector comprising, the resin composition comprising:
about 30 to about 70 wt. % poly(1,4-cyclohexanedimethylene terephthalate);
about 10 to 30 wt. % of titanium dioxide; and
about 10 to 30 wt. % of a glass fibers having a flat surface and an aspect ratio in cross-section, of 1:1 to 4.5:1; and
0.1 and 10 wt. % of one or more additives selected from the group consisting of mold release agents, antioxidants, quenchers, light stabilizers, nucleating agents and combinations thereof.
17 . The resin composition of claim 16 , wherein the composition comprises a benzotriazole light stabilizer, a quencher, and an antioxidant selected from the group consisting of an organophosphonite, a thioether ester, and combinations thereof.
18 . A reflector for a light-emitting semiconductor diode, comprising a molded product of a resin composition of claim 1 , shaped for reflecting light from a light-emitting semiconductor element.
19 . A light-emitting semiconductor unit comprising a light-emitting semiconductor element, leads connecting electrodes of a light-emitting semiconductor diode element with external electrodes, respectively; and a reflector for a light-emitting semiconductor unit according to claim 18 , including a molded product of a resin composition comprising:
about 25 to about 80 wt. % of an heat-resistant aromatic polyester having a melting point temperature of at least 260° C. of which
at least about 80 mole percent of diol repeat units, derivable from 1,4-cyclohexanedimethanol, are of formula (I):
and at least about 80 mole percent of dicarboxylic acid repeat units, derivable from terephthalic acid, are of formula (II):
about 5 to 50 wt. % of a titanium dioxide filler; and
about 5 to 50 wt. % of glass fiber having a non-circular or flat surface.
20 . A light-emitting semiconductor package comprising a reflector and a solder, wherein the reflector comprises a resin composition comprising:
about 25 to about 80 wt. % of heat-resistant aromatic polyester have a melting point temperature higher than the point of the solder of which
at least about 80 mole percent of diol repeat units, derivable from 1,4-cyclohexanedimethanol, are of formula (I):
and at least about 80 mole percent of dicarboxylic acid repeat units, derivable from terephthalic acid, are of formula (II):
about 5 to 50 wt. % of titanium dioxide filler; and
about 5 to 50 wt. % of glass fiber having a flat surface.
21 . A resin composition for molding a reflector for a light-emitting semiconductor unit comprising:
about 25 to about 80 wt. % of an organic resin having a melting point or transition glass temperature of at least 260° C., wherein the organic resin is poly(1,4-cyclohexanedimethylene terephthalate);
about 5 to 50 wt. % of white titanium dioxide filler; and
about 5 to 50 wt. % of glass fiber having a flat surface.
22 . A reflector for a light-emitting semiconductor diode, comprising a molded product of a resin composition of claim 21 , shaped for reflecting light from a light-emitting semiconductor element.
23 . A light-emitting semiconductor unit comprising a light-emitting semiconductor element, leads connecting electrodes of a light-emitting semiconductor element with external electrodes, respectively; and a reflector for a light-emitting semiconductor unit according to claim 22 .