JPH0541663B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition that has excellent light reflectance, light shielding properties, and heat resistance as well as good moldability. More specifically, the present invention relates to a blend resin composition comprising an aromatic polyester resin, a polyamide resin, and a polycarbonate resin. In contrast, Light Emission Diode (hereinafter referred to as LED
This invention relates to resin compositions used for reflective plates, lighting reflectors, etc. Synthetic resins containing inorganic fillers, especially titanium oxide, are widely used as materials for reflective plates. However, in some cases, such as reflectors for LEDs, which have made remarkable progress in recent years, which require a manufacturing process that involves inserting diodes into a reflector molded from synthetic resin and hardening it with thermosetting epoxy resin, and in other cases, such as reflectors for lighting. When constantly exposed to high temperatures, heat resistance is required in addition to optical properties such as light reflectance and light shielding properties, and excellent moldability is required because complex and precise shapes and beautiful appearances are required. is necessary. For example, if the heat resistance temperature of the LED reflector is improved from 80 to 90 degrees Celsius of conventionally used ABS resin, etc., to 130 degrees Celsius or more, the curing time of conventional epoxy is 15 to 15 degrees Celsius.
It is now possible to drastically shorten the time from 16 hours to 5 to 6 hours, and the effect on productivity improvement is expected to be enormous. In response to such demands for improved heat resistance, resins in which titanium oxide is blended with crystalline resins such as polycarbonate or inorganic filler-reinforced polybutylene terephthalate, polyethylene terephthalate, and polyamide have been developed. In the case of such a single-based resin, even when a large amount of titanium oxide is blended, sufficient light-shielding properties cannot be obtained, making it difficult to achieve its original purpose. In addition, crystalline resins reinforced with inorganic filler-reinforced resins are prone to sink marks due to dimensional changes during crystallization, making it difficult to obtain a beautiful appearance for products with complex and precise shapes such as LED reflectors. It is extremely difficult. The present inventors have arrived at the present invention as a result of intensive research aimed at producing a resin composition that maintains a good balance between light reflectance and light-shielding properties and has excellent heat resistance and moldability. That is, the present invention comprises 10 to 40% by weight of an aromatic polyester resin comprising an aromatic dicarboxylic acid or a derivative thereof, a dihydric phenol or a derivative thereof, 15 to 55% by weight of a polyamide resin, 15 to 45% by weight of a polycarbonate resin, and titanium oxide. This is a resin composition used for LED reflectors, lighting reflectors, etc., containing 10 to 30% by weight. The aromatic polyester resin used in the present invention is generally called polyarylate, and has many excellent properties such as heat resistance, dimensional stability, electrical properties, and flame resistance, and is used in a wide range of fields such as extrusion molding and injection molding. It is used. Preferred aromatic dicarboxylic acids constituting the aromatic polyester resin used in the present invention include terephthalic acid and isophthalic acid, and mixtures thereof are particularly preferred in terms of melt processability and overall performance. In the case of such a mixture, the mixing ratio is not limited, but preferably terephthalic acid/isophthalic acid = 9/1 to 1/9 (weight ratio), particularly 7 in terms of melt processability and balance of performance. A weight ratio of /3 to 3/7 is desirable. Dihydric phenol is represented by the general formula below. Here, R ₁ , R ₂ , R ₃ , R ₄ , R ₁ ′, R ₂ ′, R ₃ ′,
R ₄ ' is selected from _the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a halogenated hydrocarbon group; may be substituted with one or more halogen groups). The dihydric phenols used in the present invention include:
For example, 2,2-bis(4-hydroxyphenyl)
-propane, 2,2-bis(4-hydroxy-
3,5-dibromophenyl)-propane, 2,2
-bis(4-hydroxy-3,5-dichlorophenyl)-propane, 4,4'-dihydroxyphenyl sulfone, 4,4''-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenylketone,
4,4'-dihydroxydiphenylmethane, 2,2
-bis(4-hydroxy3,5dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-ethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxy Diphenyl, benzoquinone, etc. These may be used alone or as a mixture.
Further, these divalent phenols may be substituted with a substituted compound or other isomers, and ethylene glycol, butylene glycol, etc. may be used in combination with these divalent phenols. The most typical divalent phenols are:
2,2-bis(4-hydroxyphenyl)propane, commonly referred to as bisphenol A. Such aromatic polyester resins are produced by various methods such as solution polymerization, melt polymerization, interfacial polymerization, etc., and are produced using phenol/tetrachloroethane = 6/4.
(weight ratio) of 1 g/g measured at 25°C in a mixed solvent.
Logarithmic viscosity at dl is 0.5 or more, preferably 0.55
That's all. The polyamide resin in the present invention is selected from polycabramide, polylaurinlactam, polyhexamethylene adivamide, and poly-11-aminoundecanoic acid. These are independent or copolymers,
It may be a mixture. The relative solution viscosity of the preferred polyamide resin is the value measured at 25°C in 96% sulfuric acid.
2.0 or higher. The polycarbonate used in the present invention is 4,4-
Dioxydiallylalkane polycarbonate, such as bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxy-3,5-dichlorophenyl)methane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, It is obtained from 4,4-dioxydiphenylalkane such as bis(4-hydroxyphenyl)phenylmethane and phosgene or diphenyl carbonate. Such polycarbonates are manufactured by various methods such as known melt polymerization, solution polymerization, and interfacial polymerization, and have a logarithmic viscosity of 0.48 or more at 1 g/dl measured in tetrachloroethane at 25°C.
Preferably it is 0.50 or more. The titanium oxide used in the present invention is preferably of rutile type. In the resin composition according to the present invention, if the weight percent of the aromatic polyester resin is less than 10%, heat resistance is poor, and if it exceeds 40%, kneading properties during melt blending are poor, resulting in a stable resin composition. I can't. Furthermore, if the weight percent of the polyamide resin is less than 15%, the light shielding property will be poor even when a large amount of titanium oxide is blended, and if it exceeds 55%, the heat resistance will be poor. Blending polycarbonate resin improves fluidity and moldability, but its weight %
If it is less than 15%, the improvement effect will be small, and if it exceeds 45%, the light shielding property will be poor and the light reflectance will also decrease. Regarding the content of titanium oxide, if it is less than 10% by weight, the light reflectance and light shielding properties will not be sufficient, and if it is less than 30% by weight.
If it exceeds this, the impact strength of the molded product will decrease and it will become brittle. The preferred composition ratio (wt%) in the present invention is 14 to 25% aromatic polyester resin, polyamide resin
19-48%, polycarbonate resin 15-34%, and titanium oxide 15-25%. The resin composition of the present invention may be produced by adding titanium oxide to a resin composition obtained by melt-extruding an aromatic polyester resin, a polyamide resin, and a polycarbonate resin in a similar manner, or by melt-extruding an aromatic polyester resin, a polyamide resin, and a polycarbonate resin. Polyester resin, polyamide resin, polycarbonate resin and titanium oxide may be made simultaneously by melt extrusion. In particular, in the latter case, a melt extruder with good kneading ability is used to
If the components are extruded simultaneously, the residence time in the heated molten state can be shortened, and a resin composition with excellent light reflectance can be obtained economically. Furthermore, the resin composition according to the present invention contains flame retardants such as halogenated hydrocarbons and antimony oxide to impart flame retardancy, a fluorescent brightener to increase apparent whiteness, and carbon to enhance light-shielding properties. In order to facilitate mold release during black and molding, release agents such as silicone resin and wax, and antioxidants such as polyhydric phenols and copper compounds may be added and mixed. Among these additives, the amounts of flame retardants and antioxidants are determined as appropriate depending on the degree required for the product, but the amounts of fluorescent brighteners, carbon black, and mold release agents are determined based on the resin composition. A trace amount of 0.1% by weight or less is sufficient. It is also possible to add polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate to the resin composition of the present invention in a small amount of less than 5% by weight. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1, Comparative Examples 1 to 2 Polyarylate obtained from a 1:1 molar ratio mixture of terephthalic acid/isophthalic acid and bisphenol A (phenol/tetrachloroethane = 6/4
(weight ratio), concentration 1 g/dl, logarithmic viscosity measured at 25°C: 0.61) 15.2 parts by weight, polycapramide (relative solution viscosity measured at 25°C in 96% concentrated sulfuric acid: 3.10) 35.5
Parts by weight, polycarbonate obtained from bisphenol A and phosgene (in tetrachloroethane at 25°C)
Logarithmic viscosity at 1 g/dl measured at: 0.52)
27.3 parts by weight of rutile titanium oxide and 22 parts by weight of rutile titanium oxide were mixed and stirred in a blender, dried under vacuum at 110°C for 6 hours, and then melted and extruded in an extruder to create a wire, which was then cooled with water and cut. I got a chip. After drying this chip under vacuum at 110° C. for 6 hours, a disk with a thickness of 1/16 inch and a test piece with a thickness of 1/8 inch were produced using an injection molding machine. The moldability was extremely good, and a molded product with a beautiful appearance without sink marks, burrs, welds, etc. could be easily obtained. Synthetic resins for LED reflectors currently on the market,
That is, it contains 25% by weight of rutile titanium oxide.
Regarding ABS and modified polyphenylene oxide (Comparative Examples 1 and 2), the same disks and test samples as above were prepared for comparison. The resin composition according to the present invention was tested under ASTM D-648 (load: 18.6 kg/cm ² ) using a 1/8 inch thick test piece.
It gave a heat distortion temperature of 141°C, which was the highest value compared to the comparative samples. Also, the thickness is 1/16
When an inch disk was left in a constant temperature bath set at 150° C. for 1 hour, the comparative samples were all significantly deformed, but the resin composition according to the present invention did not deform at all. In a light-shielding test in which the resin composition of the present invention and the modified polyphenylene oxide were viewed through a 16-inch-thick disk through the slit of a box equipped with a 100KW light bulb in a dark room, no light passed through the resin composition of the present invention and the modified polyphenylene oxide showed no light passing through the ABS.
gave a marked difference. Also, using the same disk
Wavelength 440 ~ by Model 307 Color Analyzer
The light reflectance measured at 780 mμ is 93 for the resin of the present invention.
%, which is significantly superior to 80-85% for ABS and modified polyphenylene oxide. Example 2, Comparative Examples 3 to 7 The results shown in Table 1 were obtained in the same manner as in Example 1, except that the amounts of aromatic polyester resin, polyamide resin, polycarbonate resin, and titanium oxide were changed.

[Table] In Table 1, PAR, PA, and PC represent aromatic polyester, polyamide, and polycarbonate, respectively, and the same resins as those used in Example 1 were used. Melt extrusion characteristics were determined by observing the molding workability of the extruded wire extruded from an extruder, and injection moldability was determined by observing the occurrence of sink marks, burrs, etc. in the product after molding. The light shielding property, light reflectance, heat distortion temperature, and heat distortion resistance at 150°C were determined in the same manner as in Example 1, and the impact strength was determined by the tensile impact value measured in accordance with ASTM D-1822. The resin compositions prepared in Comparative Examples 3 to 7 were insufficient in any of the various properties necessary for a resin composition for a reflective plate, and therefore could not be put to practical use. As is clear from the comparison between the example and the comparative example,
A resin composition that satisfies the requirements of the present invention has excellent moldability, light-shielding properties, light reflectance, and heat resistance, and is a resin composition for reflective plates that is extremely effective for LED reflectors, lighting reflectors, and the like.

Claims (1)

[Claims] 1 10 to 40% by weight of aromatic polyester resin consisting of aromatic dicarboxylic acid or its derivative and dihydric phenol or its derivative, 15 to 55% by weight of polyamide resin, and polycarbonate resin 15
A resin composition with a light reflectance of 88% or more and excellent light-shielding properties, consisting of ~45% by weight and 10-30% by weight of titanium oxide.