JP2019143097A - Polyester resin composition for reflective material, and reflective material - Google Patents

Abstract

To provide a polyester resin composition for a reflective material, having high flowability in molding while favorably maintaining mechanical strength and heat resistance.SOLUTION: The polyester resin composition for a reflective material includes: 30 to 80 pts.mass of a polyester resin (A) having a melting point (Tm) or glass transformation temperature (Tg) of 250°C or more, measured by a differential scanning calorimeter (DSC); 5 to 50 pts.mass of titanium oxide (B) having an average particle diameter of 0.3 to 0.6 μm; and 1 to 50 pts.mass of an inorganic filler (C) (with the proviso that the total of (A), (B), and (C) is 100 pts.mass).SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin composition for a reflector and a reflector.

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

  In addition to being required to be able to stably maintain a high reflectance under the usage environment, the reflective material may be required to have high mechanical strength and heat resistance. For example, the LED package includes a housing part (reflecting material) provided 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. . Such an LED package is surface-mounted on a printed wiring board or the like (reflow soldering process). In the reflow soldering process, since the LED package is exposed to a high temperature environment exceeding 250 ° C., it is also required that the reflectance can be maintained (having heat resistance) even under such a high temperature.

In recent years, the number of LED packages mounted on the final product has been reduced due to cost reduction requirements for the product. As a result, the brightness of the light source has been increased, and as a result, the reflective material is required to maintain the reflectance even in an environment exposed to severe heat and light.

  On the other hand, Patent Document 1 discloses a resin containing polycyclohexylene dimethylene terephthalate (PCT), titanium oxide, a polymer reinforcing agent such as a glycidyl methacrylate polymer, and an antioxidant as a reflector material. A composition is disclosed. The titanium oxide used in the examples of Patent Document 1 has a small average particle diameter of 1.6 nm.

Special table 2009-507990

  However, according to the study by the present inventors, it has been found that the resin composition shown in Patent Document 1 has good mechanical strength and heat resistance, but may have low fluidity during molding. .

  This invention is made | formed in view of the said situation, and it aims at providing the polyester resin composition for reflectors with the high fluidity | liquidity at the time of shaping | molding, having favorable mechanical strength and heat resistance.

[1] 30 to 80 parts 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 250 ° C. or higher, and a volume-based cumulative particle size distribution 50% particle diameter D ₅₀ includes 0.3 to 0.6 μm of titanium oxide (B) 5 to 50 parts by mass and inorganic filler (C) 1 to 50 parts by mass (however, (A), (B ) And (C) is 100 parts by mass), a polyester resin composition for reflectors.
[2] The titanium oxide (B) is a titanium oxide having a surface coating layer,
The said surface coating layer is a polyester resin composition for reflectors as described in [1] which consists of an at least 1 sort (s) of inert inorganic oxide chosen from the group which consists of a silica, an alumina, and a zirconia.
[3] The polyester resin composition for a reflector according to [2], wherein the surface coating amount by the inert inorganic oxide is 1 to 20 parts by mass with respect to 100 parts by mass of titanium oxide as a raw material.
[4] The content of the titanium oxide (B) is 35 to 40 parts by mass with respect to a total of 100 parts by mass of (A), (B), and (C), and any of [1] to [3] A polyester resin composition for a reflector according to claim 1.
[5] The polyester resin (A) includes a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a dialcohol, and the component unit (a1) derived from the dicarboxylic acid is: 30-100 mol% of component units derived from terephthalic acid and 0 component units derived from aromatic dicarboxylic acids other than terephthalic acid, based on 100 mol% of the total of component units (a1) derived from dicarboxylic acid. The component unit (a2) derived from the dialcohol containing at least 70 mol% is at least a component unit derived from an alicyclic dialcohol having 4 to 20 carbon atoms and a component unit derived from an aliphatic dialcohol. The polyester resin composition for reflectors according to any one of [1] to [4], including one.
[6] The polyester resin composition for a reflector according to [5], wherein the component unit (a2) derived from the dialcohol includes a component unit derived from an alicyclic dialcohol having a cyclohexane skeleton.
[7] The component unit (a2) derived from the dialcohol contains 30 to 100 mol% of the component unit derived from cyclohexanedimethanol with respect to a total of 100 mol% of the component unit (a2) derived from the dialcohol. And [5] or [6] a polyester resin composition for a reflector, comprising 0 to 70 mol% of a component unit derived from the aliphatic dialcohol.
[8] The polyester resin composition for reflectors according to any one of [1] to [7],
Reflective material.
[9] The reflective material according to [8], which is a reflective material for a light-emitting diode element.

  ADVANTAGE OF THE INVENTION According to this invention, the polyester resin composition for reflectors with high fluidity | liquidity at the time of shaping | molding can be provided, maintaining mechanical strength and heat resistance favorably.

As a result of intensive studies, the inventors have shown that a resin composition containing a polyester resin (A) has a 50% particle diameter D ₅₀ in a volume-based cumulative particle size distribution (as a white pigment) in Patent Document 1. By containing titanium oxide (B) that is moderately larger than conventional titanium oxide, the resin at the time of molding can be obtained without significantly deteriorating the mechanical strength and heat resistance of the resulting molded product (while maintaining good). It has been found that the fluidity of the composition can be increased. The reason is not clear, since the 50% particle size D ₅₀ reasonably large titanium oxide (B) is the specific surface area is reasonably small, difficult to aggregate at the time of molding, well dispersed in the polyester resin (A) It is thought that it is easy.

On the other hand, increasing the 50% particle size D ₅₀ of titanium oxide (B), the surface area of the particles of titanium oxide (B) is reduced, etc. It is easy to reduce the diffraction effects at the surface, sufficient reflectance is It may be difficult to obtain.
On the other hand, the present inventors made the titanium oxide (B) titanium oxide surface-treated with an inert inorganic compound substantially free of organic matter, thereby impairing the reflectance of the resulting molded product. I found more difficult things. The reason for this is not clear, but the surface treatment makes it easier to disperse titanium oxide (B), and the surface coating layer of titanium oxide (B) does not contain an organic substance. This is considered to be due to the ability to suppress coloration due to alteration by high-temperature heat during melt kneading. The present invention has been made based on these findings.

1. Polyester resin composition for reflector The polyester resin composition for reflector of the present invention contains a polyester resin (A), titanium oxide (B), and an inorganic filler (C).

1-1. Polyester resin (A)
The polyester resin (A) includes a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a dialcohol.

  The component unit (a1) derived from dicarboxylic acid contains 30 to 100 mol% of the component unit derived from terephthalic acid and 0 to 70 mol% of the component unit derived from an aromatic dicarboxylic acid other than terephthalic acid. Is preferred. The ratio of the component unit derived from terephthalic acid contained in the component unit (a1) derived from dicarboxylic acid is more preferably 40 to 100 mol%, 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 component unit (a1) derived from the dicarboxylic acid is more preferably 0 to 60 mol%, further preferably 0 to 40 mol%. It is possible. However, the total amount of the component units (a1) derived from dicarboxylic acid is 100 mol%.

  The component unit (a1-1) derived from terephthalic acid can 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.

  Examples of the component unit (a1-2) derived from an aromatic dicarboxylic acid other than terephthalic acid include component units derived from isophthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid and combinations thereof, and aromatics thereof. Component units derived from esters of dicarboxylic acids (preferably alkyl esters of 1 to 4 carbon atoms of aromatic dicarboxylic acids) are included.

  Component unit (a1) derived from dicarboxylic acid is a small amount of component unit derived from aliphatic dicarboxylic acid or component unit derived from polyvalent carboxylic acid having three or more carboxylic acid groups in the molecule, together with the above component unit May further be included. The ratio of the component unit derived from the aliphatic dicarboxylic acid and the component unit derived from the polyvalent carboxylic acid contained in the component unit (a1) derived from dicarboxylic acid may be 10 mol% or less in total.

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

  The component unit (a2) derived from a dialcohol preferably includes a component unit derived from an alicyclic dialcohol having 4 to 20 carbon atoms and / or a component unit derived from an aliphatic dialcohol.

  The component unit (a2-1) derived from the alicyclic dialcohol can increase the heat resistance of the polyester resin composition and reduce 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 are included. Among these, from the standpoint that the heat resistance of the polyester resin composition is further increased, the water absorption is further reduced, and the availability is easy, a compound having a cyclohexane skeleton is preferable, and 1,4-cyclohexanedimethanol is more preferable. .

  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 component units derived from. Therefore, the cis / trans ratio of the component unit derived from the alicyclic dialcohol is preferably 50/50 to 0/100, and more preferably 40/60 to 0/100.

  The component unit (a2-2) derived from the aliphatic dialcohol further enhances the melt fluidity of the polyester resin composition. Examples of aliphatic dialcohols include ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol and dodecamethylene glycol.

  The component unit (a2) derived from dialcohol includes only one of the component unit (a2-1) derived from the alicyclic dialcohol and the component unit (a2-2) derived from the aliphatic dialcohol. May be included, or both may be included. The component unit (a2) derived from a dialcohol is a component unit derived from an alicyclic dialcohol (preferably a component unit derived from a dialcohol having a cyclohexane skeleton, more preferably 1,4-cyclohexanedimethanol. It is preferable that 30-100 mol% of component units) and 0-70 mol% of component units derived from aliphatic dialcohol are included. Component unit derived from alicyclic dialcohol contained in component unit (a2) derived from dialcohol (preferably derived from dialcohol having a cyclohexane skeleton, more preferably derived from 1,4-cyclohexanedimethanol The ratio of the component unit to be used is more preferably 50 to 100 mol%, still more preferably 60 to 100 mol%. The ratio of the component unit derived from the aliphatic dialcohol contained in the component unit (a2) derived from the dialcohol is more preferably 0 to 50 mol%, and further preferably 0 to 40 mol%. However, the total amount of the component units (a2) derived from dialcohol is 100 mol%.

  The component unit (a2) derived from a dialcohol may further contain a small amount of a component unit derived from an aromatic diol together with the component unit. Examples of aromatic dialcohols 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 component unit (a2) derived from the dialcohol 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 250 ° C. or more, preferably 270 ° C., more preferably 280 ° C. It is. When the melting point or glass transition temperature is 250 ° C. or higher, for example, discoloration or deformation due to heat of the molded product of the polyester resin composition can be suppressed even when exposed to a high temperature in a reflow soldering process or the like. The melting point (Tm) or glass transition temperature (Tg) of the polyester resin (A) is preferably 350 ° C. or lower, and more preferably 335 ° C. or lower. When the melting point or glass transition temperature is 350 ° C. or lower, it is easy to suppress the decomposition of the polyester resin (A) during melt molding.

  The melting point 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 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 flowability during molding of the polyester resin composition is good, and the mechanical strength is also excellent. The intrinsic viscosity of the polyester resin (A) can be adjusted by, for example, the progress of the polycondensation reaction (polymerization temperature, polymerization time) or the addition of a molecular weight adjusting agent (monofunctional carboxylic acid or monofunctional alcohol). .

The intrinsic viscosity [η] 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] = η _SP / [C (1 + kη _SP )]

In the above formula, each algebra or variable represents the following.
[Η]: Intrinsic viscosity (dl / g)
η _SP : Specific viscosity C: Sample concentration (g / dl)
k: Constant (slope determined by measuring the specific viscosity of samples with different solution concentrations (three or more points), plotting the solution concentration on the horizontal axis and η _SP / C on the vertical axis)

η _SP is obtained by the following equation.
η _SP = (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) can be produced by reacting a dicarboxylic acid component and a dialcohol component by a known method. The reaction between the dicarboxylic acid component and the dialcohol component may be performed in the presence of a molecular weight modifier. Thereby, the intrinsic viscosity [η] of the polyester resin (A) may be adjusted to the above range.

  Examples of molecular weight modifiers 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. In addition, the aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent in the cyclic structure portion. Examples of 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 It is. 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 may be 0 to 0.07 mol, preferably 0 to 0.05 mol, with respect to 1 mol of the total amount of the dicarboxylic acid component when the dicarboxylic acid component and the dialcohol component are reacted. .

  The content of the polyester resin (A) in the polyester resin composition of the present invention is 30 to 80 masses when the total of the polyester resin (A), titanium oxide (B) and inorganic filler (C) is 100 mass parts. Part. When the content of the polyester resin (A) is 30 parts by mass or more, a polyester resin composition excellent in heat resistance that can withstand a reflow soldering process and the like is easily obtained without impairing moldability. The content of the polyester resin (A) is more preferably 40 to 70 parts by mass when the total of the polyester resin (A), titanium oxide (B), and inorganic filler (C) is 100 parts by mass, More preferably, it is 50-60 mass parts.

1-2. Titanium oxide (B)
Titanium oxide (B) has the function of whitening the polyester resin composition and improving the light reflection function.

The 50% particle size D ₅₀ in the volume-based cumulative particle size distribution of titanium oxide (B) is 0.3 to 0.6 μm. When a 50% particle diameter D ₅₀ 0.3μm or more, the specific surface area is not too titanium oxide (B), since the hard aggregate, favorably easily dispersed in the polyester resin composition, the polyester resin composition Easy to increase fluidity. When the 50% particle size D ₅₀ is 0.6μm or less, or cause skin irritation of the surface of the molded product, that the mechanical strength (such as toughness) is lowered significantly be suppressed. From the above viewpoint, the 50% particle diameter D ₅₀ of titanium oxide (B) is more preferably 0.4 to 0.6 μm. 50% particle size D ₅₀ of the titanium oxide (B) can be adjusted by the particle size of the titanium oxide as a raw material.

50% particle size _{D 50} of the titanium oxide (B) can be measured by the following method. That is, based on the transmission electron micrograph, the distribution curve is obtained by plotting the particle amount (%) in each particle size section of the primary particles using an image diffractometer (Luzex IIIU). The resulting yield a cumulative distribution curve based on volume from the distribution curve, the value at the cumulative degree of 50% in the cumulative distribution curve, and the 50% particle diameter D _50.

Titanium oxide (B) may be used alone or in combination of two or more. For example, it may be a combination of two or more of titanium oxide 50% particle size _{D 50} different (B).

  Titanium oxide (B) may be surface-treated titanium oxide or titanium oxide that has not been surface-treated. Especially, it is preferable that a titanium oxide (B) is a surface-treated titanium oxide from a viewpoint of making it easy to improve the dispersibility of a titanium oxide (B) and making the fluidity | liquidity of a polyester resin composition easy. However, the surface-treated titanium oxide is an inert material that does not substantially contain an organic substance from the viewpoint of suppressing a decrease in reflectance caused by the organic substance being denatured and colored by heat at the time of melt-kneading the resin composition. Titanium oxide surface-treated with an inorganic compound is preferable.

  That is, the titanium oxide (B) preferably has titanium oxide and a surface coating layer made of an inert inorganic oxide that covers at least a part of the surface of the titanium oxide. Consisting of an inert inorganic oxide means that the content of components (for example, organic substances) other than the inert inorganic oxide in the surface coating layer is 2% by mass or less, preferably 0% by mass. Such titanium oxide (B) is difficult to aggregate and easily disperses well in the polyester resin (A), so that the fluidity of the polyester resin composition at the time of molding is easily improved, and the resulting molded product has a high reflectance. Hard to be damaged.

  The crystal structure of titanium oxide as a raw material is not particularly limited, and may be either anatase type or rutile type. Among these, from the viewpoint of improving the reflectance, the crystal structure of titanium oxide is preferably a rutile type.

  The shape of the titanium oxide is not particularly limited, but from the viewpoint of facilitating uniformization of the reflectance of the obtained molded product, a shape having a small aspect ratio, that is, a shape close to a sphere is preferable.

  Examples of the inert inorganic oxide constituting the surface coating layer include silica, alumina, zirconia, and the like, preferably silica. The inert inorganic oxide may be one type or two or more types. From the viewpoint of making it easier to improve the dispersibility of titanium oxide (B), the inert inorganic oxide is preferably at least two kinds including at least silica.

  The surface coating amount by the inert inorganic oxide is not particularly limited, but is preferably 1 to 20 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of titanium oxide as a raw material, for example. preferable. If the surface coating amount is a certain level or more, the dispersibility of the titanium oxide (B) in the polyester resin composition is easily improved, and the fluidity of the polyester resin composition at the time of molding is easily improved, so the reflectance of the molded product is impaired. It's hard to get it.

  Examples of commercially available titanium oxide (B) include R-960 and R-706 manufactured by Chemers.

  The content of titanium oxide (B) in the polyester resin composition of the present invention is 5 to 50 masses when the total of the polyester resin (A), titanium oxide (B) and inorganic filler (C) is 100 parts by mass. Part. When the content of titanium oxide (B) is 5 parts by mass or more, the whiteness of the polyester resin composition is likely to increase and the reflectance is likely to increase. When the content of titanium oxide (B) is 50 parts by mass or less, the fluidity and moldability during molding are hardly impaired. The content of titanium oxide (B) is more preferably 10 to 50 parts by mass when the total of the polyester resin (A), titanium oxide (B) and inorganic filler (C) is 100 parts by mass, The amount is more preferably 20 to 40 parts by mass, and further preferably 35 to 40 parts by mass.

1-3. Inorganic filler (C)
The inorganic filler (C) is an inorganic compound filler having a spherical, fibrous or plate shape. From the viewpoint of further increasing the strength and toughness of the polyester resin composition, the inorganic filler (C) is preferably fibrous.

  Examples of fibrous inorganic fillers (C) include glass fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, zonotlite, zinc oxide whisker, milled fiber and Includes cut fibers. 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 (reflecting material) is easy to improve. . 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 (C) is usually 5 mm or less, from the viewpoint of making the fibrous inorganic filler (C) difficult to break and easy to finely disperse in the resin. It is preferable that it is 4 mm or less. The average fiber length (l) of the fibrous inorganic filler (C) is preferably 2 μm or more and more preferably 8 μm or more from the viewpoint of further increasing the strength of the polyester resin composition.

  The aspect ratio (average fiber length (l) / average fiber diameter (d)) of the fibrous inorganic filler (C) is preferably 5 to 2000, and more preferably 30 to 600. The greater the aspect ratio, the higher the strength and rigidity of the polyester resin composition.

The average fiber length (l) and the average fiber diameter (d) of the fibrous inorganic filler (C) in the polyester resin composition 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) Arbitrary 100 fibrous inorganic fillers (C) of the obtained filtrated material are observed with a scanning electron microscope (SEM) (magnification: 50 times), and the length and diameter of each fiber are measured. To do. And the average value of fiber length can be made into average fiber length (l), and the average value of fiber diameter can be made into average fiber diameter (d).

  When the content of the inorganic filler (C) in the polyester resin composition for a reflector of the present invention is 100 parts by mass of the total of the polyester resin (A), titanium oxide (B), and inorganic filler (C), It is preferable that it is 1-50 mass parts. When the content of the inorganic filler (C) is 1 part by mass or more, the mechanical strength and heat resistance of the polyester resin composition are easily increased, and when it is 50 parts by mass or less, the flow during molding of the polyester resin composition Properties and moldability are not easily impaired. The content of the inorganic filler (C) is more preferably 5 to 40 parts by mass when the total of the polyester resin (A), titanium oxide (B), and inorganic filler (C) is 100 parts by mass. Preferably, it is 7-25 mass parts.

1-4. Other ingredients (D)
The polyester resin composition for a reflector according to the present invention may further contain other components than the above-described components (A) to (C) depending on the application within a range not impairing the effects of the present invention. Examples of other ingredients, titanium oxide (B) titanium oxide other than (50% particle diameter D ₅₀ of titanium oxide of less than 0.3 [mu] m) and, antioxidant (phenols described above, amines, sulfur compounds , Organic phosphorus, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, hindered amines, ogizanides, etc.), heat stabilizers (lactone compounds, vitamin Es, hydroquinones, copper halides, iodine compounds, etc.) ), Other polymers (olefins such as polyolefins, ethylene / propylene copolymer, ethylene / 1-butene copolymer, olefin copolymers such as propylene / 1-butene copolymer, polystyrene, polyamide , Polycarbonate, polyacetal, polysulfone, polyphenylene oxide, fluororesin, silico Resins, LCP, etc.), flame retardants (bromine, chlorine, phosphorus, antimony, inorganic, etc.), optical brighteners, plasticizers, thickeners, antistatic agents, release agents, pigments, crystal nuclei Agents, lubricants and the like.

1-4-1. Antioxidant The polyester resin composition for a reflector of the present invention preferably contains an antioxidant. Examples of the antioxidant include phenols (including hindered phenols).

  Phenols are compounds having a phenol skeleton or a hindered phenol skeleton. Examples of phenols include 2,6-di-tert-butyl-4-hydroxytoluene (BHT), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadodecyl- 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate and the like are included. Examples of commercially available products include IRGANOX 1010, 1076, 1726 (above, manufactured by BASF Japan).

  The content of the antioxidant is preferably 2.5 parts by mass or less when the total of the polyester resin (A), titanium oxide (B), and inorganic filler (C) is 100 parts by mass. It is more preferable that the amount is not more than parts.

1-4-2. Lubricant The polyester resin composition for a reflector of the present invention preferably contains a lubricant. Examples of the lubricant include unmodified polyolefin wax and modified polyolefin wax. Modified polyolefin wax is a modified product of polyolefin (for example, ethylene (co) polymer or propylene (co) polymer) with unsaturated carboxylic acid (for example, maleic anhydride) or styrene (for example, styrene), or by air oxidation. It may be an oxidatively modified product. When the resin composition for a reflector of the present invention further contains a modified polyolefin wax, the fluidity at the time of molding can be further improved and the releasability from the mold can be improved. Examples of the lubricant include high wax 800P, 1120H (manufactured by Mitsui Chemicals) and the like.

  The content of the lubricant is preferably 0.1 to 5 parts by mass when the total amount of the polyester resin (A), titanium oxide (B) and inorganic filler (C) is 100 parts by mass. More preferably, it is 3 parts by mass. When the content of the lubricant is within the above range, the fluidity at the time of molding the polyester resin composition can be sufficiently enhanced.

1-4-3. Crystal Nucleating Agent The polyester resin composition for a reflector of the present invention preferably contains a crystal nucleating agent. Examples of crystal nucleating agents include metal salt compounds such as 2,2-methylenebis (4,6 di-t-butylphenyl) sodium phosphate, aluminum tris (pt-butylbenzoate), stearate; Sorbitol compounds such as (p-methylbenzylidene) sorbitol and bis (4-ethylbenzylidene) sorbitol; inorganic substances such as talc, calcium carbonate and hydrotalcite are included. Among these, talc is preferable from the viewpoint of easily increasing the crystallinity of the molded product. One of these crystal nucleating agents may be used alone, or two or more thereof may be used in combination.

  The content of the crystal nucleating agent in the polyester resin composition for a reflector of the present invention is 0.1 when the total of the polyester resin (A), titanium oxide (B) and inorganic filler (C) is 100 parts by mass. It is preferable that it is -5 mass parts, and it is more preferable that it is 0.1-3 mass parts. When the content of the crystal nucleating agent is within the above range, the crystallinity of the molded product can be sufficiently increased, and sufficient mechanical strength can be easily obtained.

1-5. Physical Properties The reflectance of light having a wavelength of 620 nm of the polyester resin composition for a reflector of the present invention is preferably 90% or more, and more preferably 94% or more. The reflectivity can be measured using a molded product obtained by molding the polyester resin composition for a reflector of the present invention as a test piece, and the reflectivity of the test piece is measured using CM3500d manufactured by Konica Minolta. The thickness of the sample piece can be 0.5 mm.

2. Method for Producing Polyester Resin Composition for Reflector The polyester resin composition of the present invention is prepared by using at least the aforementioned component (A), component (B) and component (C) in a known manner such as a Henschel mixer, a V blender, a ribbon. Produced by a method of mixing with a blender or tumbler blender, or after the above mixing, further melt kneading with a single screw extruder, multi-screw extruder, kneader or Banbury mixer, and granulating or grinding after the above melt kneading. Can do.

  The polyester resin composition for a reflector of the present invention is preferably a compound such as a pellet obtained by mixing the above components with a single screw extruder or a multi-screw extruder, then melt-kneading, granulating or pulverizing. . The compound is preferably used as a molding material. The melt-kneading is preferably performed at a temperature 5 to 30 ° C. higher than the melting point of the polyester resin (A). The lower limit of the melt kneading temperature is preferably 255 ° C, more preferably 275 ° C, and further preferably 295 ° C. The upper limit of the melt kneading temperature is preferably 360 ° C, more preferably 340 ° C.

3. Reflective Material The reflective material of the present invention is a molded product obtained by molding the polyester resin composition for reflective material of the present invention.

  The molding can be performed by a known molding method. Examples of known molding methods include injection molding, insert molding including hoop molding, melt molding, extrusion molding, inflation molding, and blow molding.

  The reflective material of the present invention is a molded article having at least a light reflecting surface, and can have any shape depending on the application. For example, the reflective material of the present invention can be a casing or a housing having a surface that reflects at least light. The surface that reflects light may be a flat surface or a curved surface (including a spherical surface). Specifically, the light reflecting surface may have a box shape, a funnel shape, a bowl shape, a parabolic shape, a columnar shape, a conical shape, a honeycomb shape, or the like.

  The reflective material of the present invention is used as a reflective material for various light sources such as an organic EL and a light emitting diode (LED). Especially, it is preferable to be used as a reflective material of a light emitting diode (LED), and it is more preferable to be used as a reflective material of a light emitting diode (LED) corresponding to surface mounting.

  An LED package having the reflective material of the present invention as a reflective material of a light emitting diode (LED) is mounted on a substrate, a housing portion provided on the substrate and having a space for mounting an LED, and the space. It can have LED and the sealing member which seals LED. And the housing part which has the space for mounting LED can be used as the reflecting material of this invention. In such an LED package, 1) a step of forming a reflecting plate on a substrate to obtain a housing portion; 2) a step of disposing the LED in the housing portion and electrically connecting the LED and the substrate; 3) It can be manufactured through a process of sealing the LED with a sealant. In the sealing step, the sealant is heated at a temperature of 100 to 200 ° C. and thermally cured. Furthermore, in the reflow soldering process when mounting the LED package on the printed board, the LED package is exposed to a high temperature of 250 ° C. or higher.

  Such an LED package can be used for, for example, electric and electronic parts, indoor lighting, outdoor lighting, automobile lighting, and the like.

  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)>
(Synthesis of 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 reaction, 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).

  The polyester resin (A-1) obtained had an intrinsic viscosity [η] of 0.6 dl / g and a melting point of 290 ° C. The intrinsic viscosity [η] and the melting point were measured by the following methods.

(Intrinsic viscosity)
The obtained polyester resin (A-1) was 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 was measured under the condition of 25 ° C. ± 0.05 ° C. using an Ubbelohde viscometer, and the intrinsic viscosity [η] was calculated by applying the following equation.
[Η] = η _SP / [C (1 + kη _SP )]
[Η]: Intrinsic viscosity (dl / g)
η _SP : 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 determined by measuring the specific viscosity of samples with different solution concentrations (three or more points), plotting the solution concentration on the horizontal axis and η _SP / C on the vertical axis)
η _SP = (t−t0) / t0

(Melting point (Tm))
Melting | fusing point (Tm) was measured based on JIS-K7121 with the differential scanning calorimeter (DSC). Specifically, a DSC measurement pan in which a sample is enclosed is set in X-DSC7000 (manufactured by SII), and the temperature is raised to 320 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. After maintaining for a minute, the temperature was lowered to 30 ° C. by measuring the temperature drop 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”.

<Titanium oxide (B)>
R-960: Titanium oxide particles surface-treated with alumina and silica (Alumina content: 3.7% by mass, silica content: 6.1% by mass relative to the raw material titanium oxide) No surface treatment with organic matter, 50% particle size (D ₅₀ ) 0.5 μm

<Titanium oxide for comparison>
Ishihara Sangyo Co., Ltd., Tyco PC-3: Titanium oxide particles surface-treated with alumina hydrate, silica hydrate, trimethylol propanol and organohydrogensiloxane, 50% particle size (D ₅₀ ) 0.21 μm

The 50% particle diameter (D ₅₀ ) of titanium oxide was measured by the following method.

(50% particle size (D ₅₀ ))
First, based on a transmission electron micrograph, an amount of particle (%) in each particle size section of primary particles was plotted using an image diffractometer (Luzex IIIU) to obtain a distribution curve. From the obtained distribution curve, a volume-based cumulative distribution curve was obtained, and the value at a cumulative degree of 50% in this cumulative distribution curve was taken as 50% particle diameter (D ₅₀ ).

<Inorganic filler (C)>
Glass fiber: average fiber length (l) 3 mm, average fiber diameter (R) 6.5 μm, aspect ratio (l / R) 462 (ECS03T-171DE / P9W manufactured by Nippon Electric Glass Co., Ltd., silane compound treated product)
The average fiber length (l) and average fiber diameter (R) of the glass fiber were measured as follows.

(Average fiber length, average fiber diameter)
Of the inorganic filler (C), arbitrary 100 fiber lengths and fiber diameters were each measured 50 times using a scanning electron microscope (SEM). And the average value of the obtained fiber length was made into the average fiber length, and the average value of the obtained fiber diameter was made into the average fiber diameter. The aspect ratio was defined as average fiber length / average fiber diameter.

<Other components (D)>
Irganox 1010 (antioxidant): tetrakis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionic acid] pentaerythritol (manufactured by BASF)
PEP-36 (antioxidant): bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol phosphite (manufactured by ADEKA Corporation, molecular weight 633, melting point 234-240 ° C.)
ET-5 (nucleating agent): Talc (Matsumura Sangyo Co., Ltd.)
High wax 1120H (lubricant): special monomer-modified polyethylene wax (Mitsui Chemicals, molecular weight 1200, melting point 107 ° C., melt viscosity (140 ° C.) 40 mPa · s)

2. Preparation and Evaluation of Polyester Resin Composition <Example 1 and Comparative Example 1>
Polyester resin (A), titanium oxide, inorganic filler (C) and other components (D) were mixed in a tumbler blender at the composition ratio shown in Table 1. The obtained mixture was melt kneaded at a cylinder temperature of 300 ° C. with a twin screw extruder (TEX30α manufactured by Nippon Steel Works), 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 polyester resin composition.

  The reflection characteristics, moldability and bending characteristics of the obtained polyester resin composition were evaluated by the following methods.

<Reflection characteristics>
(Initial reflectance)
The obtained polyester resin composition was injection-molded under the following molding conditions using the following molding machine to obtain a test piece having a length of 30 mm, a width of 30 mm, and a thickness of 0.5 mm.
Molding machine: SE50DU manufactured by Sumitomo Heavy Industries, Ltd.
Cylinder temperature: melting point (Tm) of polyester resin (A) + 10 ° C.
Mold temperature: 150 ° C

The reflectance of a wavelength region of 360 nm to 740 nm was determined for the obtained test piece using Minolta CM3500d. The reflectance at 620 nm was used as a representative value, and was used as the initial reflectance.
When the initial reflectance was 90% or more, there was no practical problem, and when it was 94% or more, it was judged good.

(Reflectance after reflow test)
The sample piece whose initial reflectance was measured was left in an oven at 170 ° C. for 2 hours. Next, heat treatment (reflow soldering) of this sample piece was performed using an air reflow soldering apparatus (AIS-20-82-C manufactured by Atec Techtron Co., Ltd.) with the surface temperature of the sample piece being 260 ° C. and holding for 20 seconds. The same heat treatment as in the 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.
When the amount of decrease in reflectance before and after the reflow test was 4% or less of the initial reflectance, it was judged that there was no practical problem and it was good.

(Reflectance after UV light irradiation)
The test piece whose initial reflectance was measured was left in the following ultraviolet irradiation apparatus for 250 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: Daipura Wintes Co., Ltd., Super Winmini Output: 16 mW / cm ²
When the amount of decrease in reflectance before and after UV light irradiation was 1% or less of the initial reflectance, it was judged that there was no problem in practical use and that it was satisfactory.

<Moldability>
(Flow length)
The obtained polyester 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: Sodick Plustec, Tupar TR40S3A
Injection set pressure: 2000 kg / cm ²
Cylinder setting temperature: melting point (Tm) of polyester resin (A) + 10 ° C.
Mold temperature: 30 ℃

<Bending characteristics>
The obtained polyester resin composition was injection-molded under the following molding conditions using the following molding machine to obtain a test piece having a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm.
Injection molding machine: Sodick Plustec, Tupar TR40S3A
Cylinder temperature: 300 ° C
Mold temperature: 150 ° C

  The obtained test piece was allowed to stand for 24 hours in 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 humidity of 50% RH with a bending tester: ABES manufactured by NTESCO, span 26 mm, bending speed 5 mm / min. Bending strength, bending elastic modulus, and deflection amount at this time Was measured.

  Table 1 shows the compositions and evaluation results of the polyester resin compositions obtained in Example 1 and Comparative Example 1.

As shown in Table 1, the polyester resin composition of Example 1 containing titanium oxide (B) having a 50% particle size (D ₅₀ ) of 0.3 μm or more has a 50% particle size (D ₅₀ ) of 0. It turns out that the fluidity | liquidity at the time of shaping | molding is remarkably higher than the polyester resin composition of the comparative example 1 containing a titanium oxide of less than 3 micrometers. Moreover, it turns out that the polyester resin composition of Example 1 has the favorable reflective characteristic, heat resistance, and mechanical strength of the level comparable with the polyester resin composition of the comparative example 1.

  According to the present invention, it is possible to provide a polyester resin composition for a reflector having high mechanical strength and heat resistance and high fluidity during molding.

Claims (9)

30-80 parts 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 250 ° C. or higher;
5 to 50 parts by mass of titanium oxide (B) having a 50% particle diameter D ₅₀ of 0.3 to 0.6 μm in a volume-based cumulative particle size distribution;
1 to 50 parts by mass of an inorganic filler (C) (however, the total of (A), (B) and (C) is 100 parts by mass), a polyester resin composition for a reflector. The titanium oxide (B) is a titanium oxide having a surface coating layer,
The surface coating layer is composed of at least one inert inorganic oxide selected from the group consisting of silica, alumina, and zirconia.
The polyester resin composition for reflectors according to claim 1. The surface coverage by the inert inorganic oxide is 1 to 20 parts by mass with respect to 100 parts by mass of titanium oxide as a raw material.
The polyester resin composition for reflectors according to claim 2. Content of the said titanium oxide (B) is 35-40 mass parts with respect to a total of 100 mass parts of (A), (B), and (C).
The polyester resin composition for reflectors according to any one of claims 1 to 3. The polyester resin (A) includes a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a dialcohol.
The component unit (a1) derived from the dicarboxylic acid is 30 to 100 mol% of the component unit derived from terephthalic acid, with respect to 100 mol% in total of the component unit (a1) derived from the dicarboxylic acid, and terephthalic acid Containing 0 to 70 mol% of component units derived from an aromatic dicarboxylic acid other than
The component unit (a2) derived from the dialcohol includes at least one of a component unit derived from an alicyclic dialcohol having 4 to 20 carbon atoms and a component unit derived from an aliphatic dialcohol.
The polyester resin composition for reflectors as described in any one of Claims 1-4. The component unit (a2) derived from the dialcohol includes a component unit derived from an alicyclic dialcohol having a cyclohexane skeleton,
The polyester resin composition for reflectors according to claim 5. The component unit (a2) derived from the dialcohol has 30 to 100 mol% of the component unit derived from cyclohexanedimethanol with respect to 100 mol% in total of the component unit (a2) derived from the dialcohol, Containing 0 to 70 mol% of component units derived from aliphatic dialcohol,
The polyester resin composition for reflectors according to claim 5 or 6. Including the polyester resin composition for a reflector according to any one of claims 1 to 7,
Reflective material. A reflective material for a light emitting diode element;
The reflective material according to claim 8.