JP2017071728A - Polyester resin composition, method for manufacturing reflector and method for manufacturing light-emitting diode (led) element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which has high reflectance, shows little reduction in the reflectance even when exposed heat in a step of manufacturing an LED element or a reflow solder step in mounting or heat or light generated from a light source, and can obtain a reflector having high mechanical strength.SOLUTION: A polyester resin composition contains 30 to 80 mass% of a polyester resin (A) having a melting point (Tm) or a glass transition temperature (Tg) measured by differential scanning calorimeter (DSC) of 270°C or higher, 5 to 50 mass% of a white pigment (B), 0.1 to 4.5 mass% of a metal hydroxide (C) composed of at least one selected from the group consisting of aluminum hydroxide, zinc hydroxide and a hydroxide of alkaline earth metal, and 0 to 50 mass% of an inorganic filler (D) (total of polyester resin (A), white pigment (B), metal hydroxide (C) and inorganic filler (D) is 100 mass%).SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin composition, a method for producing a reflector, and a method for producing a light emitting diode (LED) element.

  Light sources such as light emitting diodes (LEDs) and organic ELs are widely used for lighting, display backlights, and the like, taking advantage of their low power and long life. In order to efficiently use light from these light sources, reflectors are used in various aspects.

  For example, the LED element includes a housing part formed on a substrate and having a space for mounting the LED, the LED mounted in the space, and a sealing member for sealing the LED. For example, such an LED element includes: 1) a process of manufacturing the housing part by forming the reflector of the present invention on a substrate; 2) an LED is disposed inside the housing part; It is manufactured by a method including a step of electrically connecting, and 3) a step of sealing the LED with a sealant. At this time, in the step 3) of sealing, the sealant is heated at a temperature of 100 to 200 ° C. in order to thermoset. Since this heat also reaches the reflecting plate, the reflecting plate is required to maintain the reflectance even at the above temperature. Further, in the reflow soldering process when mounting the LED element on the printed board, the LED package is exposed to a high temperature of 250 ° C. or higher. The reflector is required to maintain the reflectance even at the above temperature. Furthermore, the reflector is required to maintain the reflectance even when exposed to heat or light generated from the LED for a long period of time in a use environment.

  In order to satisfy the above requirements, it has been studied to use a semi-aromatic polyamide resin composition as a material for the reflector. As an example of a semi-aromatic polyamide resin composition that can be used as a material for the reflector, Patent Documents 1 and 2 include a resin composition containing PA9T, PA11 / 10T, titanium oxide, a filler, and magnesium hydroxide. It is disclosed. Further, in place of polyamide, for example, heat-resistant polyester such as polycyclohexylene dimethylene terephthalate (PCT) is used to suppress the decrease in the reflectance of the reflector by improving the base polymer. For example, Patent Document 3 discloses a heat-resistant polyester resin composition containing polyester such as PCT, titanium oxide, a filler, and magnesium oxide. Patent Document 3 suggests that when the heat-resistant polyester resin composition contains calcium oxide or magnesium oxide, the reflectance of the reflector can be maintained for a longer period of time.

JP 2006-257314 A Special table 2014-520190 gazette JP 2014-105336 A

  However, the molded product obtained from the semi-aromatic polyamide resin composition as described in Patent Documents 1 and 2 may cause discoloration due to the terminal amino group or amide bond. These discolorations may reduce the reflectivity of the reflector.

  Moreover, even in the heat-resistant polyester resin composition as described in Patent Document 3, visible light, ultraviolet light, discoloration due to heating, etc. may occur, resulting in a decrease in reflectance when exposed to heat or light. It could not be sufficiently suppressed.

  Therefore, a composition that can produce a reflector with little discoloration and less decrease in reflectivity even when exposed to heat or light received during manufacture or mounting of LED elements, or from a light source in a use environment. There is still a demand for things.

  Furthermore, since the performance of light sources such as higher brightness of LEDs has been improved, the reflector is required to further improve whiteness and reflectivity.

  Further, as a result of further investigation by the present inventors, the reflector manufactured using a heat-resistant polyester resin composition containing a metal oxide as in Patent Document 3 has a low mechanical strength, which makes it possible to reduce the size of the apparatus. It turned out to be difficult to deal with.

  The present invention has been made in view of the above circumstances, has high reflectivity, and is exposed to heat such as a reflow soldering process during LED element manufacturing or mounting, or heat or light generated from a light source in a use environment. However, the polyester resin composition capable of obtaining a reflector with little reduction in reflectivity and high mechanical strength (particularly bending strength), and production of a reflector using such a polyester resin composition It is an object of the present invention to provide a method and a method for manufacturing an LED element using such a reflector.

In view of said subject, this invention relates to the following polyester resin compositions.
[1] 30-80% by mass of a polyester resin (A) having a melting point (Tm) or glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 270 ° C. or higher,
5-50 mass% of white pigment (B),
0.1 to 4.5% by mass of a metal hydroxide (C) composed of at least one selected from the group consisting of aluminum hydroxide, zinc hydroxide and alkaline earth metal hydroxides;
A polyester resin composition containing 0 to 50% by mass of inorganic filler (D) (however, the total of polyester resin (A), white pigment (B), metal hydroxide (C), and inorganic filler (D) is 100% by mass).
[2] The polyester resin composition according to [1], wherein the metal hydroxide (C) is one or both of magnesium hydroxide and calcium hydroxide.
[3] The polyester resin (A)
Component unit (a1) derived from dicarboxylic acid containing 30 to 100 mol% of component unit derived from terephthalic acid and 0 to 70 mol% of component unit derived from aromatic dicarboxylic acid other than terephthalic acid,
A component unit derived from an alicyclic dialcohol having an alicyclic hydrocarbon skeleton having 4 to 20 carbon atoms, or a component unit derived from a dialcohol containing a component unit derived from an aliphatic dialcohol (a2);
The polyester resin composition according to [1] or [2].
[4] The polyester resin composition according to [3], wherein the component unit (a2) derived from the dialcohol includes a component unit derived from an alicyclic dialcohol having a cyclohexane skeleton.
[5] The component unit (a2) derived from the dialcohol is composed of 30 to 100 mol% of the component unit derived from 1,4-cyclohexanedimethanol and 0 to 70 mol% of the component unit derived from the aliphatic dialcohol. The polyester resin composition according to [3] or [4].
[6] The polyester resin composition according to any one of [1] to [5], wherein the white pigment (B) is titanium oxide.
[7] For a total of 100% by mass of (A), (B), (C) and (D),
The polyester resin composition according to any one of [1] to [6], further comprising 0.01 to 2% by mass of a hindered amine light stabilizer (E).

Moreover, this invention relates to the manufacturing method of the following reflecting plates.
[8] A method for producing a reflector, comprising a step of molding the polyester resin composition according to any one of [1] to [7].

Moreover, this invention relates to the manufacturing method of the following light emitting diode (LED) elements.
[9] A step of producing a housing part by forming a reflector produced by the method according to [8] on a substrate,
A step of disposing a light emitting diode inside the manufactured housing portion and electrically connecting the light emitting diode and the substrate; and a step of sealing the light emitting diode connected to the substrate with a sealant. ,
A method for manufacturing a light emitting diode (LED) element.

  According to the present invention, the reflectivity is high, and the reflectivity is lowered even when exposed to heat such as a reflow soldering process during manufacturing or mounting of an LED element, or heat or light generated from a light source in a use environment. And a reflector having a high mechanical strength (particularly bending strength), a method for producing a reflector using such a resin composition, and a method for producing such a reflector. Provided is a method for manufacturing an LED element using a reflective plate.

1. Polyester resin composition The polyester resin composition of the present invention contains a polyester resin (A), a white pigment (B), and a metal hydroxide (C). The polyester resin composition of the present invention may further contain an inorganic filler (D). The polyester resin composition of the present invention may further contain a hindered amine light stabilizer (E). The polyester of the present invention may further contain other components.

1-1. Polyester resin (A)
The polyester resin (A) has a plurality of ester structures represented by-(C = O) -O- in the molecule, and has a melting point (Tm) or glass transition temperature measured by a differential scanning calorimeter (DSC). If (Tg) is 270 degreeC or more, the kind will not be specifically limited.

  From the viewpoint of further improving the heat resistance of the polyester resin composition, the polyester resin (A) is derived from a dicarboxylic acid component unit (a1) having a component unit derived from an aromatic dicarboxylic acid and a dialcohol having an alicyclic skeleton. And a dialcohol component unit (a2) having a component unit.

  From the viewpoint of further improving the heat resistance of the polyester resin composition, the dicarboxylic acid component unit (a1) has 30 to 100 mol% of component units derived from terephthalic acid, and is derived from an aromatic dicarboxylic acid other than terephthalic acid. It is preferable to have 0 to 70 mol% of component units. The ratio of the component unit derived from terephthalic acid contained in the dicarboxylic acid component unit (a1) is more preferably 40 to 100 mol%, and further preferably 60 to 100 mol%. When the content of the component unit derived from terephthalic acid is high, the heat resistance of the polyester resin composition is further increased. The ratio of the component unit derived from the aromatic dicarboxylic acid other than terephthalic acid contained in the dicarboxylic acid component unit (a1) is more preferably 0 to 60 mol%, and further preferably 0 to 40 mol%.

  The component unit derived from the terephthalic acid may be a component unit derived from terephthalic acid or a terephthalic acid ester. The terephthalic acid ester is preferably an alkyl ester of 1 to 4 carbon atoms of terephthalic acid, and examples thereof include dimethyl terephthalate.

  Preferred examples of the component unit derived from the aromatic dicarboxylic acid other than terephthalic acid include component units derived from isophthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid and combinations thereof, and the aromatic dicarboxylic acid. The component unit derived from ester (preferably C1-C4 alkylester of aromatic dicarboxylic acid) is contained.

  The total amount of the component units derived from the terephthalic acid and the component units derived from the aromatic dicarboxylic acid is preferably 100 mol%. However, depending on the desired properties, the dicarboxylic acid component unit (a1) is a polyvalent component having a small amount of component units derived from an aliphatic dicarboxylic acid or having three or more carboxylic acid groups in the molecule together with the component unit. A component unit derived from a carboxylic acid may be further included. The ratio of the component unit derived from the aliphatic dicarboxylic acid and the component unit derived from the polyvalent carboxylic acid in the dicarboxylic acid component unit (a1) may be, for example, 10 mol% or less.

  The number of carbon atoms of the component unit derived from the aliphatic dicarboxylic acid is not particularly limited, but is preferably 4 to 20, and more preferably 6 to 12. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. Of these aliphatic dicarboxylic acids, adipic acid is preferred. Examples of the component unit derived from the polyvalent carboxylic acid include tribasic acids including trimellitic acid and pyromellitic acid, and polybasic acids.

  In addition, from the viewpoint of further improving the heat resistance of the polyester resin composition, the dialcohol component unit (a2) is derived from a component unit derived from an alicyclic dialcohol having 4 to 20 carbon atoms or an aliphatic dialcohol. It is preferable to have a component unit.

  The component unit derived from the alicyclic dialcohol can increase the heat resistance of the polyester resin composition and reduce the water absorption. Examples of the alicyclic dialcohol include dialcohols having an alicyclic hydrocarbon skeleton having 4 to 20 carbon atoms such as 1,3-cyclopentanediol, 1,3-cyclopentanedimethanol, 1,4 -Cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-cycloheptanediol and 1,4-cycloheptanedimethanol. Among these, the alicyclic dialcohol is a compound having a cyclohexane skeleton from the viewpoint that the heat resistance of the polyester resin composition is further increased, the water absorption is further reduced, and the availability is easy. Is preferred, and 1,4-cyclohexanedimethanol is more preferred.

  The alicyclic dialcohol has isomers such as a cis / trans structure. From the viewpoint of further improving the heat resistance of the polyester resin composition, the polyester resin (A) is an alicyclic dialcohol having a trans structure. It is preferable to contain more derived component units. Therefore, the cis / trans ratio of the component unit derived from the alicyclic dialcohol is preferably 50/50 to 0/100, more preferably 40/60 to 0/100.

  The component unit derived from the aliphatic dialcohol further enhances the melt fluidity of the polyester resin composition. Examples of the aliphatic dialcohol include ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol and dodecamethylene glycol.

  The dialcohol component unit (a2) may have either one or both of the component unit derived from the alicyclic dialcohol and the component unit derived from the aliphatic dialcohol. Also good. The dialcohol component unit (a2) is a component unit derived from the alicyclic dialcohol (preferably a component unit derived from a dialcohol having a cyclohexane skeleton, more preferably a component unit derived from cyclohexanedimethanol). It is preferable to have 30 to 100 mol% and 0 to 70 mol% of component units derived from the aliphatic dialcohol. A component unit derived from the alicyclic dialcohol contained in the dialcohol component unit (a2) (preferably a component unit derived from a dialcohol having a cyclohexane skeleton, more preferably a component unit derived from cyclohexanedimethanol. ) Is more preferably 50 to 100 mol%, and still more preferably 60 to 100 mol%. The ratio of the component unit derived from the aliphatic dialcohol contained in the dialcohol component unit (a2) is more preferably 0 to 50 mol%, and further preferably 0 to 40 mol%.

  The total amount of the component unit derived from the alicyclic dialcohol and the component unit derived from the aliphatic dialcohol is preferably 100 mol%. However, according to desired characteristics, the dialcohol component unit (a2) may further contain a small amount of a component unit derived from an aromatic dialcohol together with the component unit. Examples of the aromatic dialcohol include bisphenol, hydroquinone, and 2,2-bis (4-β-hydroxyethoxyphenyl) propane. The ratio of the component unit derived from the aromatic dialcohol contained in the dialcohol component unit (a2) can be, for example, 10 mol% or less.

  The melting point (Tm) or glass transition temperature (Tg) of the polyester resin (A) measured by a differential scanning calorimeter (DSC) is 270 ° C. or higher. A preferable lower limit of the melting point (Tm) or the glass transition temperature (Tg) is 290 ° C., and more preferably 330 ° C. On the other hand, the preferable upper limit of the melting point (Tm) or the glass transition temperature (Tg) is not particularly limited, but is, for example, 350 ° C., and more preferably 335 ° C. When the melting point or glass transition temperature is 270 ° C. or higher, discoloration or deformation of the reflector (molded resin composition) in the reflow soldering process is suppressed. The upper limit melting point or glass transition temperature is preferably 350 ° C. or lower because decomposition of the polyester resin (A) is suppressed during melt molding. In addition, about polyester resin (A), about resin which has both melting | fusing point (Tm) and glass transition temperature (Tg), melting | fusing point should just be 270 degreeC.

  For example, the melting point (Tm) or glass transition temperature (Tg) of the polyester resin (A) is in the range of 270 ° C. to 350 ° C., preferably in the range of 290 to 335 ° C.

  The melting point (Tm) and glass transition temperature (Tg) of the polyester resin (A) can be measured by a differential scanning calorimeter (DSC) according to JIS-K7121. Specifically, X-DSC7000 (made by SII) is prepared as a measuring apparatus. In this apparatus, a pan for DSC measurement in which a polyester resin (A) sample was sealed was set, heated to 320 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere, and held at that temperature for 5 minutes. The temperature is decreased to 30 ° C. by measuring the temperature decrease at 10 ° C./min. The temperature at the top of the endothermic peak at the time of temperature rise is defined as the “melting point”. The glass transition temperature is the temperature at the intersection of the straight line obtained by extending the base line on the low temperature side to the high temperature side and the tangent line drawn at the point where the gradient of the step-change part of the glass transition is maximized. To do.

  The intrinsic viscosity [η] of the polyester resin (A) is preferably 0.3 to 1.2 dl / g. When the intrinsic viscosity is in the above range, the fluidity during molding of the polyester resin composition for a reflector is further increased. The intrinsic viscosity of the polyester resin (A) can be adjusted to the above range by adjusting the molecular weight of the polyester resin (A). Examples of the method for adjusting the molecular weight of the polyester resin (A) include known methods including a method for adjusting the degree of progress of the polycondensation reaction and a method for adding an appropriate amount of a monofunctional carboxylic acid or a monofunctional alcohol. .

The intrinsic viscosity of the polyester resin (A) can be measured by the following procedure.
The polyester resin (A) is dissolved in a 50/50 mass% mixed solvent of phenol and tetrachloroethane to obtain a sample solution. The flow down time of the obtained sample solution is measured under the condition of 25 ° C. ± 0.05 ° C. using an Ubbelohde viscometer, and the intrinsic viscosity [η] is calculated by applying the following equation.
[Η] = ηSP / [C (1 + kηSP)]

In the above formula, each algebra or variable represents the following.
[Η]: Intrinsic viscosity (dl / g)
ηSP: specific viscosity C: sample concentration (g / dl)
k: Constant (slope obtained by measuring the specific viscosity of samples having different solution concentrations (3 or more), plotting the solution concentration on the horizontal axis, and ηsp / C on the vertical axis)

The above ηSP is obtained by the following equation.
ηSP = (t−t0) / t0

In the above formula, each variable represents the following.
t: Number of seconds that the sample solution flows (seconds)
t0: The number of seconds during which the solvent flows (seconds)

  The polyester resin (A) may be produced by a known method, or a commercially available product may be purchased. The preferred polyester resin (A) can be produced, for example, by mixing a molecular weight adjusting agent or the like in the reaction system and reacting the dicarboxylic acid component unit (a1) with the dialcohol component unit (a2). As described above, the intrinsic viscosity of the polyester resin (A) can be adjusted by blending a molecular weight modifier in the reaction system.

  Examples of the molecular weight modifier include monocarboxylic acids and monoalcohols. Examples of the monocarboxylic acid include aliphatic monocarboxylic acids having 2 to 30 carbon atoms, aromatic monocarboxylic acids, and alicyclic monocarboxylic acids. The aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent in the cyclic structure portion. Examples of the aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid. included. Examples of the aromatic monocarboxylic acid include benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid. Examples of the alicyclic monocarboxylic acid include cyclohexanecarboxylic acid.

  The addition amount of the molecular weight modifier is 0 to 0.07 with respect to 1 mol of the total amount of the dicarboxylic acid component unit (a1) when the dicarboxylic acid component unit (a1) and the dialcohol component unit (a2) are reacted. Mole, preferably 0 to 0.05 mol.

  The content of the polyester resin (A) in the polyester resin composition of the present invention is 100% by mass of the total of the polyester resin (A), the white pigment (B), the metal hydroxide (C), and the inorganic filler (D). When it is, it is 30-80 mass%. As for content of the said polyester resin (A), it is more preferable that it is 30-70 mass%, and it is further more preferable that it is 40-60 mass%. When the content of the polyester resin (A) is in the above range, a polyester resin composition having heat resistance sufficient to withstand the reflow soldering process is easily obtained without impairing moldability.

  The polyester resin composition for a reflector of the present invention may further contain one or more kinds of polyester resins having different physical properties as required.

1-2. White pigment (B)
A white pigment (B) should just whiten a polyester resin composition and can improve a light reflection function more. Specifically, the white pigment (B) preferably has a refractive index of 2.0 or more. The upper limit of the refractive index of the white pigment (B) is, for example, 4.0. Examples of the white pigment (B) include titanium oxide, zinc oxide, zinc sulfide, white lead, zinc sulfate, barium sulfate, calcium carbonate, and alumina oxide. These white pigments (B) may be used individually by 1 type, and may use 2 or more types together.

  From the viewpoint of further improving the reflectance and hiding property of the polyester resin composition, the white pigment (B) is preferably titanium oxide. The titanium oxide is preferably a rutile type. The average particle diameter of titanium oxide is preferably 0.1 to 0.5 μm, more preferably 0.15 to 0.3 μm.

  The white pigment (B) may be treated with a silane coupling agent or a titanium coupling agent. For example, the white pigment (B) may be surface-treated with a silane compound containing vinyltriethoxysilane, 2-aminopropyltriethoxysilane, and 2-glycidoxypropyltriethoxysilane.

  From the viewpoint of making the reflectance of the polyester resin composition of the present invention more uniform, the white pigment (B) preferably has a small aspect ratio, that is, a spherical shape.

  From the viewpoint of further increasing the reflectance of the polyester resin composition of the present invention, the average particle size of the white pigment (B) is preferably 0.1 μm or more and 0.5 μm or less, and 0.15 μm or more and 0.3 μm or less. It is more preferable that The average particle size of the white pigment (B) is a distribution curve obtained by plotting the particle amount (%) in each particle size interval of primary particles using an image diffractometer (Luzex IIIU) based on a transmission electron micrograph. Then, a cumulative distribution curve is obtained from the obtained distribution curve, and can be set to a value when the cumulative degree in this cumulative distribution curve is 50%.

  The content of the white pigment (B) in the polyester resin composition of the present invention is 100% by mass of the total of the polyester resin (A), the white pigment (B), the metal hydroxide (C), and the inorganic filler (D). When it is, it is 5-50 mass%. The content of the white pigment (B) is preferably 10 to 50% by mass, more preferably 10 to 40% by mass, and further preferably 10 to 30% by mass. When the content of the white pigment (B) is 5% by mass or more, the whiteness of the polyester resin composition is likely to increase and the reflectance is likely to increase. On the other hand, when the content of the white pigment (B) is 50% by mass or less, the fluidity of the polyester resin composition is further increased and the moldability is further increased.

1-3. Metal hydroxide (C)
The metal hydroxide (C) is a hydroxide of aluminum hydroxide, zinc hydroxide, or alkaline earth metal. Examples of the alkaline earth metal hydroxides include magnesium hydroxide, calcium hydroxide, strontium hydroxide and barium hydroxide.

  The metal hydroxide (C) maintains the reflectance of the polyester resin composition for a longer period. Therefore, the metal hydroxide (C) suppresses a decrease in reflectance that occurs when a polyester resin composition or a reflector formed by molding the polyester resin composition is exposed to heat or light over a long period of time. A small number of reflectors can be manufactured. In particular, when the polyester resin composition or the reflector is heated at a high temperature when mounted on an element, the reflectance may decrease in a relatively short period of time. However, since the polyester resin composition of the present invention contains the metal hydroxide (C), the reflectance can be maintained over a long period of time even after being heated at a high temperature.

  The reason for this is not clear, but the present inventors consider as follows. The more terminal carboxyl groups of the polyester resin, the easier it is to promote deterioration against heat, light and water. It is presumed that the metal hydroxide is coordinated to the terminal carboxyl group, thereby suppressing the deterioration of the polyester resin due to the carboxyl group. In addition, when the polyester resin composition contains an amount of metal hydroxide (C) described later, the metal hydroxide liberated in the polyester resin composition is coordinated with the terminal carboxyl group generated with the deterioration of the polyester resin. Therefore, it is estimated that there is an effect of suppressing deterioration of the polyester resin over a long period of time.

  From the above viewpoint, the metal hydroxide (C) is preferably magnesium hydroxide or calcium hydroxide.

  Moreover, since the polyester resin composition containing a metal hydroxide (C) has higher mechanical strength than the polyester resin composition containing a metal oxide, it is easy to cope with downsizing of the apparatus.

  Although the reason for this is not clear, the present inventors presume that the metal oxide is easier to adsorb water than the metal hydroxide, and the strength is reduced because the hydrolysis of the polyester is promoted during molding.

  From the viewpoint of further improving the moldability of the polyester resin composition of the present invention, the average particle size of the metal hydroxide (C) is preferably 0.05 μm or more and 10 μm or less, and is 0.1 μm or more and 5 μm or less. More preferably, the thickness is 0.2 μm or more and 4 μm or less. The average particle size of the white pigment (B) is a distribution curve obtained by plotting the particle amount (%) in each particle size interval of primary particles using an image diffractometer (Luzex IIIU) based on a transmission electron micrograph. Then, a cumulative distribution curve is obtained from the obtained distribution curve, and can be set to a value when the cumulative degree in this cumulative distribution curve is 50%.

  The metal hydroxide (C) is preferably subjected to a surface treatment. Examples of the surface treatment include treatment with an organic substance such as a higher fatty acid, organic acid, polyol, silicone, silane coupling agent, titanium coupling agent, or a combination thereof.

  The content of the metal hydroxide (C) in the polyester resin composition of the present invention is the total of the polyester resin (A), the white pigment (B), the metal hydroxide (C), and the inorganic filler (D) being 100. When it is defined as mass%, it is 0.1 to 4.5 mass%. The content of the metal hydroxide (C) is preferably 0.15 to 4.0 mass%, more preferably 0.2 to 4.0 mass%, and 0.25 to 3. More preferably, it is 5 mass%. When the content of the metal hydroxide (C) is 0.1% by mass or more, the reflectance of the polyester resin composition is maintained over a longer period. On the other hand, when the content of the metal hydroxide (C) is 4.5% by mass or less, the strength of the molded product obtained from the polyester resin composition can be made sufficient.

1-4. Inorganic filler (D)
The inorganic filler (D) is an inorganic compound filler having a spherical shape, a fiber shape, a plate shape, or the like. From the viewpoint of further increasing the strength and toughness of the polyester resin composition, the inorganic filler (D) is preferably fibrous.

  Examples of the fibrous inorganic filler (D) include glass fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, zonotlite, zinc oxide whisker, milled fiber. And cut fiber. One of these may be used alone, or two or more may be used in combination. Among these, wollastonite, glass fiber, and potassium titanate whisker are preferable, and wollastonite or glass fiber is more preferable because the average fiber diameter is relatively small and the surface smoothness of the molded product is easily improved. From the viewpoint of further enhancing the light shielding effect of the polyester resin composition, wollastonite is preferable, and from the viewpoint of further increasing the mechanical strength of the polyester resin composition, glass fiber is preferable.

  The average fiber length (l) of the fibrous inorganic filler (D) is usually 5 mm or less. Polyester resin that makes the fibrous inorganic filler (D) difficult to break and finely disperses the inorganic filler (D) in the resin, thereby reducing the extra stress that the resin receives during molding and the like. From the viewpoint of making (A) more difficult to thermally decompose, the average fiber length (l) is preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. Moreover, since the inorganic filler (D) is finely dispersed in the resin by setting the average fiber length (l) in the above range, the surface smoothness of the polyester resin composition is more likely to be increased. The lower limit value of the average fiber length (l) is not particularly limited, but is preferably 2 μm and more preferably 8 μm from the viewpoint of further increasing the strength of the polyester resin composition.

  From the viewpoint of facilitating fine dispersion of the fibrous inorganic filler (D) and improving the surface smoothness of the molded product, the average fiber diameter (d) of the fibrous inorganic filler (D) is 0. 0.05 to 30 μm is preferable, and 2 to 6 μm is more preferable. When the average fiber diameter (d) becomes larger, the fibrous inorganic filler (D) becomes difficult to break at the time of molding or the like, and the strength of the polyester resin composition is further increased. Moreover, since the said fibrous inorganic filler (D) can be shape | molded in the state finely dispersed when the said average fiber diameter (d) becomes larger, the surface smoothness of a polyester resin composition increases more, and a reflectance. Will increase.

The average fiber length (l) and average fiber diameter (d) of the fibrous inorganic filler (D) in the polyester resin composition (for example, a compound such as pellets) can be measured by the following method.
1) A polyester resin composition is dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), and then a filtrate obtained by filtration is collected.
2) Any 100 of the above fibrous inorganic fillers (D) are observed with a scanning electron microscope (SEM) (magnification: 50 times), and the length and diameter of each fiber are measured. measure. The average value of the fiber length can be the average fiber length (l), and the average value of the fiber diameter can be the average fiber diameter (d).

  The aspect ratio (l / d) obtained by dividing the average fiber length (l) by the average fiber diameter (d) is preferably 2 to 20, and more preferably 7 to 12. The greater the aspect ratio, the higher the strength and rigidity of the polyester resin composition.

  The content of the inorganic filler (D) in the polyester resin composition of the present invention is 100 mass of the total of the polyester resin (A), the white pigment (B), the metal hydroxide (C), and the inorganic filler (D). %, 0 to 50% by mass. It is preferable that content of the said inorganic filler (D) is 5-50 mass%, and it is more preferable that it is 5-40 mass%. When the content of the inorganic filler (D) is 5% by mass or more, the heat resistance of the resin composition of the polyester resin composition is more likely to be increased, and the surface is likely to be smoother. On the other hand, when the content of the inorganic filler (D) is 50% by mass or less, the fluidity of the polyester resin composition is further increased and the moldability is hardly impaired.

1-5. Hindered amine light stabilizer (E)
The hindered amine light stabilizer (E) has an effect of preventing deterioration of the resin mainly due to light such as ultraviolet rays and improving stability to light.

  The hindered amine light stabilizer (E) has a mass reduction rate of 0 to 50 when the temperature is kept at 340 ° C. for 10 minutes after being heated from 25 ° C. to 340 ° C. at a temperature of 20 ° C./minute in a nitrogen atmosphere. It is preferable that it is mass%, It is more preferable that it is 0-40 mass%, It is further more preferable that it is 0-30 mass%.

  Examples of hindered amine light stabilizers include N, N′-bis-2,2,6,6-tetramethyl-4-piperidyl-1,3-benzenedicarboxamide, 1,2,3, 4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetra Mixed esterified product with oxaspiro [5.5] undecane, N, N ′, N ″, N ′ ″-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6) , 6-Tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine, and poly [{6- (1,1,3,3-tetramethyl Butyl) amino-1,3,5-triazine-2 4- diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] is included.

  When the polyester resin composition of the present invention contains a hindered amine light stabilizer (E), the content of the hindered amine light stabilizer (E) is as follows: polyester resin (A), white pigment (B), metal When the total of the hydroxide (C) and the inorganic filler (D) is 100% by mass, it is 0.01-2% by mass, preferably 0.02-1.5% by mass, more preferably It is 0.03-1.0 mass%.

1-6. Other components The polyester resin composition of the present invention is an optional component, for example, an antioxidant, a light stabilizer other than a hindered amine, a heat stabilizer, etc. Various known components may be included, including polymers, flame retardants, fluorescent brighteners, plasticizers, thickeners, antistatic agents, mold release agents, pigments and crystal nucleating agents.

  Examples of the antioxidant include hindered phenols, phosphorus, amines and sulfur antioxidants.

From the viewpoint of suppressing the decomposition reaction of the polyester resin (A) and suppressing discoloration of the resin composition under a high temperature atmosphere (especially, conditions exceeding 250 ° C. as in the reflow soldering process), the antioxidant is , Hindered phenols or phosphorus antioxidants are preferred. Examples of the hindered phenol antioxidant are represented by pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the following general formula (1). Compounds are included. Examples of the phosphorus-based antioxidant include a compound having a P (OR) ₃ structure (R is an alkyl group, an alkylene group, an aryl group, an arylene group, or the like). From the above viewpoint, a compound represented by the following general formula (1) is more preferable.

  X in the general formula (1) represents an organic group. The organic group X is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cyclohexyl group, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. Examples of the substituted or unsubstituted alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, n-octyl group, n-tetradecyl group, and n-hexadecyl group. Examples of the substituted or unsubstituted aryl group having 6 to 20 carbon atoms include 2,4-di-t-butylphenyl group and 2,4-di-t-pentylphenyl group. Examples of the substituent that the alkyl group, cyclohexyl group and aryl group may have include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxy group, a methoxy group, and an oxadiazole. A group is included.

Examples of the compound represented by the general formula (1) include the following.

  The content of the antioxidant is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less based on the total of the resin components including the polyester resin (A). Further preferred.

  Examples of the light stabilizers other than the hindered amines include light stabilizers of benzotriazoles, triazines, benzophenones, and ogizanides.

  Examples of the heat-resistant stabilizer include lactone compounds, vitamin Es, hydroquinones, copper halides, and iodine compounds.

  Examples of the above other polymers include polyolefins, olefin copolymers including ethylene / propylene copolymers and ethylene / 1-butene copolymers, and olefin copolymers obtained as propylene / 1-butene copolymers. , Polystyrene, polyamide, polycarbonate, polyacetal, polysulfone, polyphenylene oxide, fluororesin, silicone resin, and LCP.

  It is preferable that the other components do not contain components or elements that become catalyst poisons. Examples of the components and elements that become the catalyst poison include sulfur-containing compounds.

1-7. Physical Properties The polyester resin composition of the present invention having the above composition preferably has fluidity that can be molded into a desired shape. From the viewpoint of further improving the moldability, the flow length when the polyester resin composition is injection-molded under the following conditions is preferably 30 mm or more, and more preferably 31 mm or more.
Injection molding equipment: Sodick Plustech, Tupar TR40S3A
Injection set pressure: 2000 kg · cm ²
Cylinder setting temperature: Melting point + 10 ° C
Mold temperature: 30 ℃

2. Method for Producing Polyester Resin Composition The polyester resin composition of the present invention can be produced by a known method for producing a polyester resin composition. Examples of the known methods include a method in which the above components are mixed in a Henschel mixer, a V blender, a ribbon blender or a tumbler blender, and after the mixing, a single screw extruder, a multi-screw extruder, a kneader or a banbury. A method of melt-kneading with a mixer and granulating or pulverizing after the melt-kneading is included.

  The melt kneading is preferably performed at a temperature 5 to 30 ° C. higher than the melting point of the polyester resin (A). The melt kneading temperature is preferably 255 ° C. or higher, more preferably 275 ° C. or higher, further preferably 295 ° C. or higher. The temperature of the melt kneading is preferably 360 ° C. or less, and more preferably 340 ° C. or less.

3. The manufacturing method of a reflecting plate, and the manufactured reflecting plate The manufacturing method of the reflecting plate of this invention includes the process of shape | molding the said polyester resin composition of this invention.

  The said shaping | molding can be performed by the well-known shaping | molding method which manufactures a reflecting plate from a polyester resin composition. Examples of the known molding method include a known heat molding method. Examples of the known thermoforming methods include injection molding, insert molding including hoop molding, melt molding, extrusion molding, inflation molding, and blow molding.

  The reflector of the present invention thus produced comprises the polyester resin (A), white pigment (B), metal hydroxide (C) and inorganic filler (D), the polyester resin composition of the present invention. Contains at the stated rate for the product. The polyester resin composition of the present invention may further contain the hindered amine light stabilizer (E) in the proportion described for the polyester resin composition of the present invention. The polyester of the present invention may further contain other components.

  In the reflector of the present invention, the reflectance of light having a wavelength of 450 nm is preferably 90% or more, and more preferably 94% or more. The said reflectance should just be the value measured by the well-known method, for example, can be made into the value obtained by measuring the molded object whose thickness is 0.5 mm using Minolta Co., Ltd. CM3500d.

The reflectance of light having a wavelength of 450 nm measured after reflowing (for example, after maintaining the state where the surface temperature is 260 ° C. for 20 seconds) of the reflector of the present invention is preferably 90% or more. The reflectance of light having a wavelength of 450 nm, measured after heating at 150 ° C. for 500 hours, is preferably 90% or more. The reflectance of light having a wavelength of 450 nm, measured after irradiation of ultraviolet rays at 16 mW / cm ² for 250 hours, is preferably 82% or more. The reflectance of light having a wavelength of 450 nm, which is measured after irradiation of ultraviolet rays at 16 mW / cm ² for 500 hours, is preferably 82% or more. It is preferable that the reflectance of the light with a wavelength of 450 nm measured after further re-irradiation with ultraviolet rays at 16 mW / cm ² for 500 hours after the reflow of the reflector of the present invention is 85% or more.

  The above reflector of the present invention is a test piece having a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm, and a bending tester: AB5 manufactured by NTSCO, span 26 mm, bent under an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%. The maximum bending stress that the test piece can withstand when the bending test is performed at a speed of 5 mm / min is preferably 80 MPa or more, and more preferably 85 MPa or more.

  The reflecting plate of the present invention can be a casing or a housing having a light reflecting surface. At this time, the shape of the surface that reflects the light may be any of a planar shape, a curved surface shape, and a spherical shape. For example, the shape of the reflector can be a box shape, a funnel shape, a bowl shape, a parabolic shape, a columnar shape, a conical shape, and a honeycomb shape.

  The reflector of the present invention can be used for manufacturing an element having a light source. Examples of the elements include organic EL elements and light emitting diode (LED) elements. The LED is preferably an LED compatible with surface mounting. In these elements, the reflector of the present invention is used as a reflector that reflects light emitted from a light source.

  The light emitting diode (LED) element having the reflection plate of the present invention includes, for example, a housing portion having a space for mounting an LED formed on a substrate, an LED mounted in the space, and the LED. And a sealing member for sealing. Such an LED element can be manufactured by the well-known method of the LED element which has a reflecting plate. Examples of the known manufacturing method include 1) a step of forming the reflector of the present invention on a substrate to manufacture the housing part, and 2) disposing an LED inside the housing part, And 3) a step of sealing the LED with a sealant.

  The reflector of the present invention may be exposed to high-temperature heat in the above step 3), or may be exposed to light including visible light and ultraviolet light generated from an LED or the like in a use environment and heat for a long time. The metal hydroxide (C) is coordinated to the terminal carboxyl group, and the decomposition reaction of the polyester resin (A) by the carboxyl group is suppressed, so there is little discoloration and high reflectance is maintained. sell. Moreover, since the said metal hydroxide (C) has the effect of pseudo bridge | crosslinking because the said metal hydroxide (C) coordinates to the terminal carbonyl group of polyester, the said reflecting plate of this invention has high bending strength.

  The reflector of the present invention can be used for various applications. Examples of such applications include various electrical and electronic components, room lighting, outdoor lighting, and automobile lighting.

  Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to the following embodiments.

  In the following, the present invention will be described with reference to examples. By way of example, the scope of the invention is not construed as limiting.

1. Preparation of material <Polyester resin (A-1)>
106.2 parts by mass of dimethyl terephthalate and 94.6 parts by mass of 1,4-cyclohexanedimethanol (cis / trans ratio: 30/70) (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed. To the mixture, 0.0037 parts by mass of tetrabutyl titanate was added, and the temperature was raised from 150 ° C. to 300 ° C. over 3 hours and 30 minutes to cause a transesterification reaction.

  At the end of the transesterification, 0.066 parts by mass of magnesium acetate tetrahydrate dissolved in 1,4-cyclohexanedimethanol was added, followed by polycondensation reaction by introducing 0.1027 parts by mass of tetrabutyl titanate. . In the polycondensation reaction, the pressure was gradually reduced from normal pressure to 1 Torr over 85 minutes, and at the same time, the temperature was raised to a predetermined polymerization temperature of 300 ° C. Stirring was continued while maintaining the temperature and pressure, and the reaction was terminated when a predetermined stirring torque was reached. Thereafter, the obtained polymer was taken out and subjected to solid phase polymerization at 260 ° C. and 1 Torr or less for 3 hours to obtain a polyester resin (A-1).

<Polyester resin (A-2)>
30 parts by mass of high-purity terephthalic acid and 49.3 parts by mass of monoethylene glycol were mixed. The mixture was heated from 100 ° C. to 260 ° C. over 6 hours under a slight pressure of 0.2 MPa · G for esterification reaction.

  At the end of the transesterification reaction, 0.021 parts by mass of germanium dioxide dissolved in ethylene glycol was added to carry out a polycondensation reaction. In the polycondensation reaction, the pressure was gradually reduced from normal pressure to 1 Torr over 60 minutes, and at the same time, the temperature was raised to a predetermined polymerization temperature of 280 ° C. Stirring was continued while maintaining the temperature and pressure, and the reaction was terminated when a predetermined stirring torque was reached. Thereafter, the obtained polymer was taken out and subjected to solid phase polymerization at 225 ° C. for 6.0 hours to obtain a polyester resin (A-2).

  The polyester resin (A-1) had an intrinsic viscosity [η] of 0.79 dl / g and a melting point of 290 ° C. The polyester resin (A-2) had an intrinsic viscosity [η] of 0.77 dl / g and a melting point of 254 ° C. The intrinsic viscosity [η] and the melting point were measured by the following methods.

(Intrinsic viscosity)
The polyester resin (A-1) and the polyester resin (A-2) were each dissolved in a 50/50 mass% mixed solvent of phenol and tetrachloroethane to obtain a sample solution. The number of seconds for each sample solution to flow was measured under the condition of 25 ° C. ± 0.05 ° C. using an Ubbelohde viscometer, and the intrinsic viscosity [η] was calculated according to the following equation.
[Η] = ηSP / [C (1 + kηSP)]
[Η]: Intrinsic viscosity (dl / g)
ηSP: specific viscosity C: sample concentration (g / dl)
t: Number of seconds that the sample solution flows (seconds)
t0: The number of seconds during which the solvent flows (seconds)
k: Constant (slope obtained by measuring the specific viscosity of samples having different solution concentrations (3 or more), plotting the solution concentration on the horizontal axis, and ηsp / C on the vertical axis)
ηSP = (t−t0) / t0

(Melting point)
The melting points of the polyester resin (A-1) and the polyester resin (A-2) were measured according to JIS-K7121. X-DSC7000 (made by SII) was prepared as a measuring apparatus. The pan for DSC measurement which enclosed polyester resin (A-1) and polyester resin (A-2) to this was set, and it heated up to 320 degreeC by the temperature increase rate of 10 degree-C / min in nitrogen atmosphere. The temperature was maintained at that temperature for 5 minutes, and then the temperature was decreased to 30 ° C. by measuring the temperature decrease at 10 ° C./min. The temperature at the peak top of the endothermic peak at the time of temperature rise was defined as “melting point”.

<White pigment (B)>
Titanium oxide (powder, average particle size: 0.21 μm)
The average particle diameter of titanium oxide is a distribution curve obtained by plotting the amount of particles (%) in each particle diameter section of primary particles using an image diffractometer (Luzex IIIU) based on a transmission electron micrograph. The cumulative distribution curve was obtained from the obtained distribution curve, and the value was obtained when the cumulative degree in the cumulative distribution curve was 50%.

<Metal hydroxide (C)>
Magnesium hydroxide (C-1) (manufactured by Kyowa Chemical Industry Co., Ltd., Kisuma 5J, with surface treatment, average particle size: 0.86 μm)
Magnesium hydroxide (C-2) (manufactured by Wako Pure Chemical Industries, 130-12215, no surface treatment, average particle size: 0.6 μm)
In addition, the average particle diameter of the metal hydroxide (C) was measured similarly to the average particle diameter of the titanium oxide.

<Metal oxide (for comparison)>
Magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd., MF-150, average particle size: 1.36 μm)
In addition, the average particle diameter of magnesium oxide was measured similarly to the average particle diameter of the titanium oxide.

<Inorganic filler (D)>
Glass fiber, average fiber length (l): 3 mm, deformed ratio 4 [7 μm × 28 μm] (Nittobo Co., Ltd. CSG 3PA-830, silane compound treated product)
The average fiber length (l) and average fiber diameter (d) of the glass fiber as a raw material were measured by the following methods. That is, the fiber length and fiber diameter of 100 glass fibers were measured through a scanning electron microscope (SEM) (magnification: 50 times). And the average value of measured fiber length was made into average fiber length (l), and the average value of fiber diameter was made into average fiber diameter (d).

<Light stabilizer (E)>
ADK STAB LA-63P (manufactured by ADEKA Corporation)

<Antioxidant>
Irganox 1010 (manufactured by BASF)

2. Preparation of Resin Resin Composition [Example 1]
53.8 parts by mass of the polyester resin (A-1) synthesized as a polyester resin (A), 35 parts by mass of titanium oxide as a white pigment (B), and magnesium hydroxide (C) as a metal hydroxide (C) C-1) as 1 part by mass and the reinforcing fiber (D) as 10 parts by mass of the glass fiber were prepared, and these were mixed using a tumbler blender. The obtained mixture was melt-kneaded at a cylinder temperature of 300 ° C. with a twin screw extruder (TEX30α manufactured by Nippon Steel Works, Ltd.), and then extruded into a strand shape. The extrudate was cooled in a water tank, and then the strands were drawn with a pelletizer and cut to obtain a pellet-shaped resin composition for a reflector. It was confirmed that the compounding property was good.

[Examples 2-7 and Comparative Examples 1-6]
Except having changed into the composition shown in Table 1 or Table 2, it carried out similarly to Example 1, and obtained the pellet-shaped resin composition of Examples 2-7 and Comparative Examples 1-4, 6. The pellet-shaped resin of Comparative Example 5 was the same as Example 1 except that the composition shown in Table 2 was changed and the cylinder temperature at the time of extrusion was changed to 280 ° C. A composition was obtained.

  Various reflectances and fluidity of the resin compositions obtained in the respective Examples and Comparative Examples were measured or evaluated by the following methods.

<Reflectance>
(Initial reflectance)
The obtained pellet-shaped resin composition was injection-molded under the following molding conditions using the following molding machine to prepare a test piece having a length of 30 mm, a width of 30 mm, and a thickness of 0.5 mm. The reflectance of the wavelength region 360 nm-740 nm was calculated | required for the obtained test piece using Minolta Co., Ltd. CM3500d. The reflectance at 450 nm was used as a representative value, and was used as the initial reflectance.
Molding machine: SE50DU, manufactured by Sumitomo Heavy Industries, Ltd.
Cylinder temperature: melting point (Tm) + 10 ° C.
Mold temperature: 150 ° C

(Reflectance after reflow test)
The sample piece whose initial reflectance was measured was left in an oven at 170 ° C. for 2 hours. Next, this sample piece is subjected to heat treatment using an air reflow soldering apparatus (AIS-20-82-C, manufactured by Atec Techtron Co., Ltd.) with a surface temperature of 260 ° C. and a temperature profile for 20 seconds. (The same heat treatment as in the reflow soldering process) was performed. After slowly cooling this sample piece, the reflectivity was measured by the same method as the initial reflectivity to obtain the reflectivity after the reflow test.

(Reflectance after heating)
The test piece whose initial reflectance was measured was left in an oven at 150 ° C. for 500 hours. Then, the reflectance of the obtained sample piece was measured by the same method as the initial reflectance, and was defined as the reflectance after heating.

(Reflectance after UV irradiation)
The test piece whose initial reflectance was measured was left in the following ultraviolet irradiation apparatus for 250 hours. Further, the test piece for which the initial reflectance was measured and the test piece after the reflow test were left in the following ultraviolet irradiation apparatus for 500 hours. Then, the reflectance of the obtained sample piece was measured by the same method as the initial reflectance, and was taken as the reflectance after UV irradiation.
Ultraviolet irradiation device: manufactured by Daipura Wintes Co., Ltd. Super Winmini Output: 16 mW / cm ²

(Reflectance after reflow and UV irradiation)
The sample piece whose initial reflectance was measured was left in an oven at 170 ° C. for 2 hours. Next, this sample piece was subjected to heat treatment (reflow) with a temperature profile in which the surface temperature of the sample piece was 260 ° C. and held for 20 seconds using an air reflow soldering apparatus (AIS-20-82-C, manufactured by Atec Techtron Co., Ltd.). The same heat treatment as in the soldering process was performed. After this sample piece was gradually cooled, it was left in the following ultraviolet irradiation apparatus for 500 hours. Then, the reflectance of the obtained sample piece was measured by the same method as the initial reflectance, and was taken as the reflectance after UV irradiation.
Ultraviolet irradiation device: manufactured by Daipura Wintes Co., Ltd. Super Winmini Output: 16 mW / cm ²

<Fluidity>
The obtained resin composition was injection molded under the following conditions using a bar flow mold having a width of 10 mm and a thickness of 0.5 mm, and the flow length (mm) of the resin in the mold was measured.
Injection molding machine: TUPARL TR40S3A manufactured by Sodick Co., Ltd.
Injection set pressure: 2000 kg / cm ²
Cylinder setting temperature: Melting point (Tm) + 10 ° C
Mold temperature: 30 ℃

<Bending strength>
The resin composition was molded under the following molding conditions using the following injection molding machine to prepare a test piece having a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm. The test piece was left for 24 hours under a nitrogen atmosphere at a temperature of 23 ° C. Next, a bending test was performed in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50% with a bending tester: AB5 manufactured by NTSCO Co., span 26 mm, bending speed 5 mm / min, and the strength was measured.
Injection molding machine: TUPARL TR40S3A manufactured by Sodick Co., Ltd.
Molding machine cylinder temperature: melting point (Tm) + 10 ° C.
Mold temperature: 150 ° C

<Heat resistance>
The test piece whose initial reflectance was measured was left in an oven at 150 ° C. for 1 minute. After slow cooling, the test piece was visually observed and evaluated according to the following criteria.
・ Evaluation criteria A: No change in the shape of the test piece before and after the heating process B: Some change while maintaining the skeleton of the test piece after the heating process C: The whole test piece melts and changes greatly in shape after the heating process

  The evaluation results of Examples 1 to 7 are shown in Table 1, and the evaluation results of Comparative Examples 1 to 6 are shown in Table 2.

  As shown in Tables 1 and 2, it can be seen that the compositions of Examples 1 to 7 maintain a higher reflectivity after 500 hours of ultraviolet irradiation than the compositions of Comparative Examples 1 and 6. This is considered because the compositions of Examples 1 to 7 contain the metal hydroxide (C).

  Further, as shown in Tables 1 and 2, the compositions of Examples 1 to 7 containing the metal hydroxide (C) have bending strength equivalent to that of the composition of Comparative Example 1, but Patent Document 3 Thus, it can be seen that the compositions of Comparative Examples 2 and 3 using magnesium oxide have lower bending strength.

  Moreover, as Table 1 and 2 shows, the composition of Examples 1-7 whose content of a metal hydroxide (C) is 0.1 mass%-4.5 mass% is the comparative example 1. Although it has bending strength equivalent to a composition, it turns out that bending strength falls the composition of the comparative example 4 whose content of a metal hydroxide (C) is 5 mass%.

  Moreover, as Table 1 and 2 shows, the composition of Examples 1-7 containing an alicyclic dialcohol component unit or an aliphatic dialcohol component unit as a dialcohol component unit (a2) has high heat resistance. However, it turns out that the composition of the comparative example 5 which does not contain an alicyclic dialcohol unit falls in heat resistance.

  The polyester resin composition of the present invention has a high reflectivity and is exposed to heat such as a manufacturing process of an LED package or a reflow soldering process when mounting the LED package, or exposed to heat or light generated from a light source in a use environment. Even if it is done, a molded article with little fall of a reflectance can be provided.

Claims (9)

30-80% by mass of a polyester resin (A) having a melting point (Tm) or glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 270 ° C. or higher,
5-50 mass% of white pigment (B),
0.1 to 4.5% by mass of a metal hydroxide (C) composed of at least one selected from the group consisting of aluminum hydroxide, zinc hydroxide and alkaline earth metal hydroxides;
A polyester resin composition containing 0 to 50% by mass of inorganic filler (D) (however, the total of polyester resin (A), white pigment (B), metal hydroxide (C), and inorganic filler (D) is 100% by mass).   The polyester resin composition according to claim 1, wherein the metal hydroxide (C) is one or both of magnesium hydroxide and calcium hydroxide. The polyester resin (A) is
Component unit (a1) derived from dicarboxylic acid containing 30 to 100 mol% of component unit derived from terephthalic acid and 0 to 70 mol% of component unit derived from aromatic dicarboxylic acid other than terephthalic acid,
A component unit derived from an alicyclic dialcohol having an alicyclic hydrocarbon skeleton having 4 to 20 carbon atoms, or a component unit derived from a dialcohol containing a component unit derived from an aliphatic dialcohol (a2);
The polyester resin composition of Claim 1 or Claim 2 containing this.   The polyester resin composition according to claim 3, wherein the component unit (a2) derived from the dialcohol includes a component unit derived from an alicyclic dialcohol having a cyclohexane skeleton.   The component unit (a2) derived from the dialcohol contains 30 to 100 mol% of the component unit derived from 1,4-cyclohexanedimethanol, and 0 to 70 mol% of the component unit derived from the aliphatic dialcohol, The polyester resin composition according to claim 3 or 4.   The polyester resin composition according to any one of claims 1 to 5, wherein the white pigment (B) is titanium oxide. With respect to a total of 100% by mass of the (A), (B), (C) and (D),
The polyester resin composition according to any one of claims 1 to 6, further comprising 0.01 to 2% by mass of a hindered amine light stabilizer (E).   The manufacturing method of a reflecting plate including the process of shape | molding the polyester resin composition as described in any one of Claims 1-7. Forming a housing part by forming a reflector manufactured by the method according to claim 8 on a substrate;
A step of disposing a light emitting diode inside the manufactured housing portion and electrically connecting the light emitting diode and the substrate; and a step of sealing the light emitting diode connected to the substrate with a sealant. ,
A method for manufacturing a light emitting diode (LED) element.