Polyester resin composition
A polyester resin composition comprises (A) about 100 parts by weight of polyester resin with a melting point greater than about 200° C. and including repeat units of Formula 1; (B) about 0.1 to about 80 parts by weight of white pigment; and (C) about 0.01 to about 80 parts by weight of filler. The polyester resin composition of the present invention does not exhibit deteriorated reflectance and impact strength and also has good heat resistance, non-yellowing property and humidity resistance and can be used in a light emitting diode (LED) reflector.
1. A reflector for a light emitting diode (LED) prepared from a polyester resin composition comprising:
(A) about 100 parts by weight of polyester resin with a melting point of about 200° C. or more and including repeat units of the following Formula 1;
(B) about 0.1 to about 80 parts by weight of white pigment; and
(C) about 0.01 to about 80 parts by weight of filler,
wherein the reflector for the light emitting diode has an initial reflectance value of about 90 or more at a wavelength of 440 nm measured using a color-difference meter and a decline of reflectance value of less than about 10 which is measured again after maintaining the reflector for the light emitting diode under conditions of 85° C. and 85% relative humidity for 144 hours:
2. The reflector for the light emitting diode (LED) of claim 1 , wherein the polyester resin (A) includes units derived from a diol component and wherein the diol component of the polyester resin (A) further includes about 85% by weight or less of ethylene glycol, based on 100% by weight of the diol component.
3. The reflector for the light emitting diode (LED) of claim 1 , wherein the polyester resin (A) has an intrinsic viscosity of about 0.4 to about 1.5 dl/g.
4. The reflector for the light emitting diode (LED) of claim 1 , wherein the white pigment (B) comprises titanium dioxide, zinc oxide, zinc sulfide, white lead, zinc sulfate, barium sulfate, calcium carbonate, aluminum oxide, or a combination thereof.
5. The reflector for the light emitting diode (LED) of claim 1 , wherein the white pigment (B) is treated with an inorganic surface treatment agent, organic surface treatment agent, or a combination thereof.
6. The reflector for the light emitting diode (LED) of claim 1 , wherein the white pigment (B) has an average particle size of about 0.05 to about 2.0 μm.
7. The reflector for the light emitting diode (LED) of claim 1 , wherein the polyester resin composition further includes an additive selected from the group consisting of UV stabilizers, fluorescence brightening agents, lubricants, release agents, nucleating agents, antistatic agents, stabilizers, reinforcement materials, inorganic additives, pigments, dyes and combinations thereof.
8. The reflector for the light emitting diode (LED) of claim 1 , wherein the reflector for the light emitting diode has a change of initial yellow index (ΔYI) of less than about 5 measured using a color-difference meter after maintaining the reflector for the light emitting diode under conditions of 85° C. and 85% relative humidity for 144 hours.
9. The reflector for the light emitting diode (LED) of claim 1 , wherein the reflector for the light emitting diode has a water uptake of less than about 2% for 20 minutes measured using a moisture analyzer after maintaining the reflector for the light emitting diode under conditions of 85° C. and 85% relative humidity for 48 hours.
10. The reflector for the light emitting diode (LED) of claim 1 , wherein the diol component of the polyester resin (A) further includes C 6 -C 21 aromatic diol, C 3 -C 8 aliphatic diol, or a combination thereof.
11. The reflector for the light emitting diode (LED) of claim 10 , wherein the C 6 -C 21 aromatic diol or C 3 -C 8 aliphatic diol include propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 3-methylpentane-2,4-diol, 2-methylpentane-1,4-diol, 2,2,4-trimethylpentan-1,3-diol, 2-ethylhexane-1,3-diol, 2,2-diethylpropane-1,3-diol, 1,4-cyclobutanedimethanol, 2,2-bis-(hydroxyethoxyphenyl)-propane, 2,2-bis-(4-hydroxypropoxyphenyl)-propane or a combination thereof.
12. The reflector for the light emitting diode (LED) of claim 1 , wherein the filler (C) comprises carbon fibers, glass fibers, boron fibers, glass bids, glass flakes, carbon black, diatom earth, clay, kaolin, talc, mica, calcium carbonate, wollastonite, potassium titanate whiskers, aluminum boric acid whiskers, zinc oxide whiskers, calcium whiskers or a combination thereof.
13. The reflector for the light emitting diode (LED) of claim 12 , wherein the glass fiber has an average length of about 0.1 to about 20 mm and an aspect ratio of about 10 to about 2000.