WO2006043462A1 - Reflector for led and method for producing the same - Google Patents

Abstract

A reflector for an LED, composed of a foamed body having a number average foamed cell diameter of 50 μm or less and made from a resin in which the wavelength of light whose light beam transmissivity at an optical path length of 250 μm lowers to 50% is 400 nm or less. Preferably, the 5% weight reduction temperature of the resin is 300°C or above.

Description

 Specification

 LED reflector and manufacturing method thereof

 Technical field

 The present invention relates to a light reflector that is applied to a light-emitting device using an LED element and a method for manufacturing the light reflector.

 Background art

 [0002] Since the 1990s, light-emitting diodes (LEDs) have progressed in multi-color with a remarkable increase in output. In particular, white LEDs are expected as next-generation light sources to replace conventional white light bulbs, halogen lamps, HID lamps, and so on. In fact, LEDs have been evaluated for their features such as long life, power saving, temperature stability, and low-voltage drive, and they are applied to displays, destination indicators, in-vehicle lighting, signal lights, emergency lights, mobile phones, video cameras, and so on. As a method of outputting white light, a method of combining a blue LED (wavelength 460 nm) and a YAG phosphor (yellow color), and a method of combining a UV LED (wavelength 380 nm) and an RZGZB phosphor are known. Perspective of visualization and color rendering The latter method is considered promising.

 [0003] A reflector is used to extract light output from the LED as efficiently as possible. As a reflector, the light in the visible region is naturally high, and it is desirable that the reflectance be as high as possible for the light emitted from the LED.

 [0004] A thermoplastic resin composition in which titanium oxide is blended with a thermoplastic resin such as polycarbonate is widely used as a reflector (for example, Patent Documents 1 and 2). The reflector has high reflection performance for light in the visible region, but it was applied to LEDs that have low reflectivity due to the absorption of light by titanium dioxide for light in the ultraviolet region even at forces near 400 nm. In some cases, the light extraction efficiency was low.

[0005] In order to solve the above problem, a method using a fibrous or flaky inorganic compound (for example, potassium titanate fiber) that also reflects ultraviolet rays has been proposed (for example, Patent Document 3). However, although it is somewhat effective, the light extraction efficiency, which has a low reflectance at 380 nm of 50 to 70%, is still low. In addition, the reflector is exposed to high temperatures in the sealing process and solder reflow process. In this process, the reflectance to light in the visible region is also greatly reduced. There was a problem.

 [0006] On the other hand, a technique for producing a foam by allowing gas to penetrate into a polyester-based resin sheet at room temperature and then degassing by raising the temperature is disclosed (for example, Patent Document 4). Further, as a similar technique, there is a technique for obtaining a foam by allowing a polysiloxane-based resin sheet to infiltrate a gas at a high temperature and then degassing it under reduced pressure (for example, Patent Document 5).

 Patent Document 1: Japanese Patent Laid-Open No. 9 3211

 Patent Document 2: JP 2001-302899 A

 Patent Document 3: Japanese Unexamined Patent Publication No. 2003-195020

 Patent Document 4: International Publication No. 97Z01117 Pamphlet

 Patent Document 5: Japanese Unexamined Patent Publication No. 2003-49018

 [0008] In view of the above problems, an object of the present invention is to provide a reflector for an LED having high reflectivity from the visible region to the ultraviolet region and a method for manufacturing the same.

 Another object of the present invention is to provide a method for manufacturing an LED reflector that can stably manufacture the plurality of LED reflectors.

 Disclosure of the invention

 [0009] As a result of intensive studies, the inventors of the present invention have been manufactured from a resin or a resin composition in which the light wavelength at which the light transmittance is reduced to 50% at an optical path length of 250 μm is 400 nm or less. If a foam with a number average cell diameter of 50 m or less is used, it is possible to obtain a reflector for an LED having an extremely high reflectivity in the visible ultraviolet region, in particular, a thermal decomposition temperature of 300 ° C or higher. It has been found that when the cocoa resin or rosin composition is foamed, a high reflectance can be maintained even after the heat treatment process during LED production.

 [0010] Further, the foam obtained by the conventional technique has a different foaming state depending on the position in the foam sheet, and the reflectance is uneven within one sheet. We found that this was caused by the fact that the amount of gas permeation and the temperature during foaming varied greatly depending on the position in the sheet.

As a preliminary study, the inventors manufactured LED reflectors one by one, and were able to obtain a product group with small reflectance unevenness for each product. However, this makes the productivity too low to provide LED reflectors at low cost. In order to increase productivity, it was necessary to foam many molded products at once. [0011] In order to solve the above problems, the present inventors control the gas permeation temperature unevenness in foam molding to be within ± 20 ° C between products, or set the temperature rise rate during heating foaming to 50 ° C. The present inventors have found that when the control is performed so that the temperature is higher than or equal to ° CZ, the reflectance can be increased and the variation in reflectance between products can be reduced.

 [0012] Preferred embodiments of the reflector for LED and the manufacturing method thereof according to the present invention are as follows.

 1. Foam with a number average foamed cell diameter of 50 m or less manufactured by a resin or a resin composition having a light wavelength power of 400 nm or less that reduces the light transmittance to 50% at an optical path length of 250 m. LED reflector made of body.

 2. The reflector for LED according to 1, wherein the 5% weight loss temperature is 300 ° C or higher, and the composition of the resin also has a resin composition strength.

 3. The method for producing a reflector for an LED according to item 1 or 2, wherein a foam is produced by allowing gas to penetrate into the resin or the resin composition and then degassing.

 4. The method for producing a reflector for an LED according to 3, wherein gas is permeated into the resin or resin composition under pressure, and then the resin or resin composition is foamed in the process of returning to normal pressure.

 5. The method for producing a reflector for an LED according to 3, wherein the resin or the resin composition impregnated with gas is foamed in the process of heating the resin or the resin composition at a temperature rising rate of 50 ° CZ or more.

6. The method of producing a reflector for an LED according to 5, wherein the temperature is increased by bringing the gas-impregnated resin or resin composition close to a planar heater within 20 cm.

 7. Put a molded body made of a plurality of greaves or greave compositions into a pressure vessel, and allow gas to penetrate into the molded body while controlling the temperature unevenness between the molded bodies within ± 20 ° C. A method for manufacturing a reflector for an LED according to any one of the above.

 8. A foam is produced by infiltrating gas into a resin or resin composition layer comprising a resin or resin composition formed on a continuous metal plate in advance, and then degassing 3 to 7! The manufacturing method of the reflector for LEDs as described in any of the above.

 9. The method for producing a reflector for an LED according to 7, wherein the temperature of each molded body is independently controlled by a heater in the pressure vessel.

10. After foaming the greaves or greaves composition layer, continuous metal plate and greaves or greaves 9. The method for producing a reflector for an LED according to 8, wherein the laminate of the composition layer is cut into smaller units.

11. The method for producing a reflector for LED according to 8 or 10, wherein a resin or a resin composition layer is formed on a metal plate by a solvent casting method.

 12. The method for producing a reflector for LED according to 8 or 10, wherein a resin or resin composition layer is formed on a metal plate by a compression molding method.

 13. The method for producing a reflector for LED according to 8 or 10, wherein the resin or resin composition layer is formed on the metal plate by thermoforming the resin or resin composition sheet.

 14. The method for producing a reflector for LED according to 8 or 10, wherein a resin or a resin composition layer is formed on a metal plate by injection molding.

 15. A method for producing a reflector for LED according to 8 or 10, wherein a curable resin or resin composition composition is applied on a metal plate and then cured to form a resin or resin composition layer. .

 16. The LED reflector according to 1 or 2, wherein the resin composition contains a thermally conductive filler.

[0013] According to the present invention, it is possible to provide a reflector for LED having high reflection performance from the visible region to the ultraviolet region and a method for manufacturing the same.

 Furthermore, according to the present invention, it is possible to provide a method for manufacturing an LED reflector that can stably manufacture the plurality of LED reflectors.

 Brief Description of Drawings

FIG. 1 is a graph showing an example of a temperature rising pattern during heating by a surface heater.

 [FIG. 2] (a) is a top view showing a copper plate used in Examples, and (b) is a cross-sectional view of a separated copper plate formed with a resin layer.

 FIG. 3 is a schematic sectional view of the autoclave used in the examples.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Preferred examples of the rosin or rosin composition used in the present invention (hereinafter, "the rosin or rosin composition" may be simply referred to as "fax") are listed below. It is not limited to this. Wavelength of light that reduces light transmittance to 50% at an optical path length of 250 m λ is 400 nm or less

 50

When the coconut resin is used, the reflectance particularly in the ultraviolet region can be increased. Preferably, λ Is not more than 380 nm, more preferably not more than ¾50 nm.

 50

 [0016] Further, it is desirable to use a resin whose reflectivity does not significantly decrease due to heat during LED manufacturing (especially sealing or solder reflow process). Such a resin should have a 5% weight loss temperature (thermal decomposition temperature) Td of 300 ° C or higher, preferably 330 ° C or higher, more preferably 380 ° C or higher. When Td is 300 ° C or higher, the deterioration of the grease is unlikely to occur during the sealing process and the solder reflow process, and the reflectance is unlikely to decrease.

 [0017] Further, when using amorphous rosin, it is desirable that the glass transition temperature Tg is 140 ° C or higher, preferably 190 ° C or higher, more preferably 210 ° C or higher. If the Tg is less than 140 ° C, the melt viscosity will be reduced at the sealing temperature, cell coalescence will easily occur, and the reflectivity may be reduced.

 However, when a cross-linked type of resin is used, the Tg may be quite low because it has a melt viscosity that is the sealing temperature even if the Tg is less than 140 ° C. If the above thermal decomposition temperature condition is satisfied, the decrease in reflectance is small.

 [0018] In the case of using crystalline resin, if the melting point Tm is 200 ° C or higher, the reflectance is less likely to decrease during sealing. However, since the melt viscosity of crystalline rosin drastically decreases at Tm or higher, the foam cells may coalesce during solder reflow and the reflectivity may decrease. Tm is desirably 220 ° C or higher, preferably 240 ° C or higher, and more preferably 260 ° C or higher.

[0019] Specific examples of such a resin include polycarbonates, acrylic polymers, silicone polymers, cycloolefin polymers, polyimides, siloxane polymers, styrene polymers, polyethers, polyesters, polyamides. , Liquid crystal polymers, and epoxy resins. For example, bisphenol A polycarbonate, bisphenol Z polycarbonate, bisphenol AF polycarbonate, fullerene-containing polycarbonate, polymethylol methacrylate, polyadamantino methacrylate, polydicyclopentadiol methacrylate, norbornene Ζ α-olefin Examples thereof include copolymers, olefin-maleimide copolymers, polyethersulfones, polyarylates, polystyrenes, polyethylene terephthalates, polyetherolene ketones, polyetherolonitriles, polyethylene terephthalates, and polyethylene naphthalates. In addition, a composition in which two or more of these rosins are mixed can also be used.

[0020] Various additives commonly used in ordinary polymer chemistry may be added to rosin. For example, tackifiers, plasticizers, flame retardants, anti-aging agents, modifiers, heat stabilizers, UV stabilizers, colorants and the like can be exemplified. There is a case where heat dissipation is required for the reflector for LED. In that case, the thermally conductive filler is preferably added in an amount of 0.1 to 60% by weight, more preferably 1 to 40% by weight. Examples of the heat conduction filler include aluminum nitride, alumina, zinc oxide, silica, titer, and lithium titanate.

 [0021] The average cell diameter of the resin foam of the present invention is 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less.

 The number average foamed cell diameter of the foamed molded product can be reduced to 50 m or less by selecting an appropriate foaming temperature according to the thermal properties of the resin to be foamed.

 [0022] The foaming method of the present invention is not particularly limited as long as it is produced by foaming rosin and satisfies the requirements of the present invention. The type of gas used for foaming is not limited as long as it penetrates the fat. For example, an inert gas such as nitrogen, carbon dioxide, and helium is preferable. The gas state may be any of gas, liquid, and supercritical state. Further, foaming may be performed using a chemical foaming agent or the like. For example, dinitrosopentamethylenetetramine, azodicarbonamide, p, p, monooxybisbenzenesulfur hydrazide, p-toluenesulfol hydrazide, p-toluenesulfol acetone hydrazone, hydrazodicarbonamide, etc. Can be mentioned. However, it is more preferable to use an inert gas because the chemical foaming agent may adversely affect the electronic components.

 [0023] An apparatus for producing a foam using an inert gas usually comprises a step of shaping a resin, and a step of infiltrating the gas into the molded body and then degassing and foaming. There are a batch-type foaming method in which the shaping process and the foaming process are separate processes, and a continuous foaming method in which the shaping and foaming are performed continuously.

 [0024] (1) Batch type foaming

 The resin molded body is placed in a pressure vessel such as an autoclave, and the gas is infiltrated into the resin by injecting the gas.

The temperature at which the gas penetrates can be arbitrarily selected. In general, the gas dissolved in It is preferable to select a temperature at which the solubility increases (for example, the solubility of carbon dioxide is increased at lower temperatures). However, at low temperatures, it takes a long time to reach saturation solubility where gas diffusion is slow. It is preferable to determine the gas penetration temperature in consideration of the balance between solubility and gas diffusion rate.

 [0025] The gas permeation time is usually from 10 minutes to 2 days, preferably from 30 minutes to 3 hours. In the case of continuous injection foaming, since the penetration efficiency is high, it is usually 20 seconds or longer and 10 minutes or shorter.

 The amount of gas penetration is determined according to the target foaming ratio. In the present invention, it is usually from 0.1 to 20% by weight, preferably from 1 to 10% by weight, based on the weight of the resin.

 Further, the pressure during gas permeation is usually 0.1 to 50 MPa, preferably 3 to 30 MPa. The temperature can be set arbitrarily.

 [0026] Here, the characteristics of the polymer material into which the gas has permeated will be described. When gas penetrates into the polymer, the movement of the polymer chain is activated. For this reason, the inflection point of the chain motion (for example, the glass transition temperature in the case of amorphous resin) also shifts to the low temperature side. Foaming occurs when the pressure in the autoclave is reduced to normal pressure at temperatures above the inflection point. On the other hand, at temperatures below the inflection point, foaming does not occur even when the pressure in the autoclave is reduced to normal pressure. After this, if the temperature rises above the inflection point, foaming occurs. In any case, the foaming time is usually 10 seconds or more and 5 minutes or less. The inflection point greatly depends on the amount of gas dissolved, and the foaming temperature cannot be determined unconditionally. However, foaming is usually performed at the following temperatures. Tc is the crystallization temperature of the resin, Tg is the glass transition temperature, Tm is the melting temperature, and Td is the 5% weight loss temperature.

 [0027] (a) In the case of amorphous resin: (Tg—150 ° C) or more, (Tg + 50 ° C) or less

 (Ii) In the case of crystalline resin: The temperature of gas permeation depends on the crystalline state when the gas permeates. When the gas is allowed to penetrate into a completely crystallized material, the temperature is (Tm−50) ° C or more and (Tm + 50) ° C or less. On the other hand, when the gas is infiltrated into a material whose crystallinity is considerably lowered by quenching the crystalline resin from the melt, the temperature is (Tg−150 ° C) or more and (Tg + 100 ° C) or less. In this case, the crystallinity can be enhanced by heat treatment at a temperature near Tc after foaming.

[0028] When the temperature is lower than the minimum temperature in each, the polymer chain hardly moves and the foaming effect is poor. There is a case. When the upper limit temperature is exceeded, a coarse foam structure may be formed. In either case, a material with excellent reflectivity cannot be obtained.

 [0029] As described above, foaming occurs in the depressurization process after gas permeation or in the heating process after depressurization. In the latter case, for example, gas is permeated at a low temperature of −30 to 60 ° C., depressurized, and further heated to a high temperature of 80 to 400 ° C. for foaming. Here, the points to be noted when foaming in the latter heating process are described.

 First, it is necessary to control the time t until the pressure is heat treated at normal pressure. This time t should be as short as possible, but it is usually within 2 hours at room temperature. It is preferably within 1 hour, more preferably within 30 minutes. If t exceeds 2 hours, the gas naturally escapes from the inside of the polymer material, resulting in poor foaming effect and a high reflectivity material may not be obtained. On the other hand, if the material is stored in a refrigerator after normal pressure, t may be long. For example, if it is stored at −30 ° C., it is possible to obtain a highly reflective material even if t is 24 hours or longer.

 [0030] The second point of caution is to control the rate of temperature rise during heating and foaming. The rate of temperature rise dTZ dt is preferably 50 ° CZ or more, more preferably 70 ° CZ or more, and even more preferably 100 ° CZ or more. If dTZdt is less than 50 ° CZ, the foaming effect is poor and a material with high reflectivity may not be obtained. Figure 1 shows an example of the temperature rise pattern. Temperature is (T f + T 0)

The time course until Z2 is approximated by a straight line using the least squares method, and the slope of the straight line is defined as dTZdt. Here, T f is a set value of the foaming temperature, and T 0 is an initial temperature before heating.

 [0031] (2) Continuous foaming

In the injection foaming method or the extrusion foaming method (continuous type) in which gas penetrates the resin in the extruder, the gas is blown into the resin being kneaded in the extruder. Amorphous fats are usually infiltrated with gas near Tg, more specifically at a temperature of (Tg-20) ° C or higher. This makes it easier for the amorphous resin and gas to be compatible. The upper limit temperature can be freely set at a temperature that does not adversely affect the resin. However, it is desirable to infiltrate at a temperature of (Tg + 250) ° C or less. If this temperature is exceeded, the foamed cells may become large or the resin may be thermally deteriorated, which may reduce the strength of the foam. In the case of crystalline resin, it is usually Τπ! Infiltrate gas in the range of ~ (Tm + 50) ° C. If it is less than Tm, molding may be difficult. (Tm + 50) ° C High! There is a risk of decomposition of soot and sallow.

[0032] When manufacturing a plurality of LED reflectors, it is preferable to suppress the gas permeation temperature unevenness as low as possible between products when performing foam molding. This is because the smaller the gas permeation temperature unevenness, the more uniform the gas solubility of the product, and the more uniform the foamed state, and the smaller the difference in physical properties (reflectance, etc.) for each product. Specifically, it is desirable to control within ± 20 ° C, preferably within ± 10 ° C. In the case of continuous foaming, since the gas is impregnated in the injection unit set at a constant temperature, it is possible to keep the foaming temperature unevenness between products relatively low. In the case of batch-type foaming, a large number of molded products are usually placed in a pressure-resistant container at one time to allow gas to permeate. At this time, it is preferable to keep the temperature in the container as constant as possible. For this purpose, for example, a stirring mechanism is provided in the container, or the temperature of the installation position of the molded product is individually controlled. On the other hand, one of the causes of temperature unevenness during gas permeation is that the thermal conductivity of the resin is low. By forming the resin layer on the metal plate, the temperature is easily transmitted and the temperature unevenness can be reduced. In addition, the use of a metal plate has the advantage of increasing the rate of temperature rise during heating and foaming. A large number of reflectors can be produced by foaming the resin layer on the metal plate and then cutting it into small units. The metal plate can be used as a heat sink as it is, or as a lead frame if it is electrically conductive.

 [0033] The method for forming the resin layer on the metal plate is not limited. For example, there are a solvent casting method, a compression molding method, etc., or a method of forming a resin sheet on the surface of a metal plate by thermoforming, a method of integrating the metal plate and the resin by injection molding, a curable resin There is a method of applying the composition to the surface of a metal plate.

[0034] Foaming may be carried out as it is in the pressure vessel used in the gas infiltration process! In the case where after the gas permeation, the inside of the pressure vessel is once brought to normal pressure and then heated and foamed, an oven or an oil nose may be used separately. However, when foaming is performed in the heating process, it is necessary to devise a method for increasing the temperature rise rate of 50 ° CZ or more for the V-type deviation of multiple resin molded products. For this purpose, it is effective to provide a stirring mechanism in the heating medium or to individually control the temperature of the installation position of the resin molded product. A planar heater can also be used without using an oven. Surface heater The upper surface is relatively constant in temperature, and if a group of resin molded products is pressed against the heater surface, Any molded product can be similarly heated to a predetermined temperature at a high heating rate. In addition, the same effect can be obtained by simply bringing the resin molded product close to the sheet heater without contacting it. In this case, the distance between the resin molded product and the planar heater is within 20 cm, preferably within 10 cm, and more preferably within 5 cm. With the above-described devices, a uniform product group with high reflectivity can be obtained.

 [Example]

[0035] [Materials used]

 The resin, inorganic filler and composition used in Examples and Comparative Examples were as follows: 1. Resin

 (1) Polyethylene terephthalate (PET): Teijin Chemicals Ltd., TR-4550BH (Tg; 80 ° C., Tc 40. C, Tm; 255. C, Td; 390. C, λ; 320 nm).

 50

 (2) Polyethersulfone sheet (PESF): Sumitomo Bakelite Co., Ltd., FS-1300 (Tg; 228. C, Td; 481, C,; 336 nm).

 50

 (3) Special polycarbonate (PC): Idemitsu Kosan Co., Ltd., Toughzet HR-27 (Tg; 267 ° C., Td: 467. C, λ: 296 nm).

 50

(4) Special polyimide (PI): Japanese Laid-Open Patent Publication No. 2002-322280 'Used synthesized in the same manner as in Example 1 (Ding ₈ ; 250 ° 0, Ding (1; 370 ° 0, λ; 361nm) .

 50

 (5) Curable silicone resin composition (SRC): Japanese Patent Application Laid-Open No. 2004-175887 'Synthesized in the same manner as in Example 1 (Tg; 130 ° C, Td; 335 ° C, λ; 288 nm) .

 50

 (6) Amorphous polyetheretherketone film (Amorphous PEEK): Victrex Emshiichi Sumilite FS—1100C was heated and dissolved, then put into a 25 ° C water bath and amorphous PEEK Films were obtained (Tg; 145 ° C, Tc; 176 ° C, Tm; 337 ° C, Td; 550 ° C, λ; 4

 50

12nm) ₀

 (7) Polymethylmetatalylate (PMMA): Sumitomo Chemical Co., Ltd., IT44 (Tg; 115 ° C, Td; 290. C, λ; 285 nm).

 50

 (8) Semi-aromatic polyamide (PA): DuPont Co., Ltd., Zytel HTN501

[0036] 2. Inorganic filler (1) Titanium acid: Ishihara Sangyo Co., Ltd., Typeter R680

 (2) Potassium titanate fiber: Otsuka Igaku Co., Ltd., Tismo D101

[0037] 3. Composition

 (l) PAZTiO resin composition, PAZ potassium titanate composition

 2

 Pellets were obtained by kneading at a weight ratio of 70/30 using a 35 mm twin screw extruder at a temperature of 330 ° C. and a screw rotation speed of 30 Orpm.

[0038] [Evaluation method]

 1. Measuring method of cell average particle size

 A tracing paper was placed on a scanning electron microscope (SEM) observation photograph, and the foamed cell that was visible through the trace was traced. The trace was binarized with an image processor, and the cross-sectional area of the foam cell was determined. Here, the individual shape of the foam cell is often approximately elliptical, but there is distortion or the like for each cell. Therefore, each cell shape was converted to a circle with the same area, and the diameter was taken as the cell diameter. The number average cell diameter was determined from the individual cell diameters thus determined.

 [0039] 2. Method of measuring light transmittance

 Using a self-recording spectrophotometer UV-2400PC manufactured by Shimadzu Corporation, light transmittance (%) was measured in the wavelength range of 700 to 250 nm. The film thickness of the sample was 250 m, and the wavelength at which the light transmittance of the material dropped to 50% was defined as the wavelength.

 50

 [0040] 3. Measuring method of reflectance

 A multi-purpose large sample chamber unit MPC-2200 manufactured by Shimadzu Corporation was attached to the above-mentioned self-recording spectrophotometer, and the reflectance (%) was measured in the wavelength range of 700 to 250 nm. Incidentally, magnesium oxide was used as a reference.

[0041] 4. Measuring method of glass transition temperature Tg, crystallization temperature Tc, melting point Tm

 Using a differential scanning calorimeter (DSC7) manufactured by Perkin Elmer Co., Tg, Tc, and Tm were measured in the cooling process (20 ° C Z min).

[0042] 5. 5% weight loss temperature (pyrolysis temperature) Td measurement method

Using a thermogravimetric analyzer (TGA) manufactured by Perkin Elma Co., Ltd., measuring the temperature when nitrogen is heated to 40 to 650 ° C at a heating rate of 20 ° CZ for 5% of the total weight. And this is T defined as d.

[0043] 6. Measuring method of temperature unevenness and heating rate

 The temperature unevenness and the rate of temperature increase were measured by bringing a temperature sensor directly into contact with the resin molded product.

 [0044] Table 1 shows the used resin Z compositions, production conditions, and the like of Examples and Comparative Examples.

[0045] Example 1

 Twenty-five pieces of the copper plate 1 shown in Fig. 2 (a) were prepared one by one, and a PET resin layer of about 250 m was formed on it by compression molding. A copper plate 1 with a PET layer is shown in Fig. 2 (b).

 [0046] The autoclave 3 shown in Fig. 3 (including 80mmφ X 150mm) was used as a gas infiltration container (batch type foaming). There are 25 sample storage areas in the autoclave, and each sample storage area is designed so that the heater temperature can be controlled independently (a temperature controller is connected to each sample position). Copper plates 4 each having a resin layer formed therein were placed in the autoclave, and carbon dioxide with a pressure increased at room temperature was introduced. Furthermore, the pressure was increased to 15 MPa while maintaining the room temperature. Next, while maintaining the pressure at 15 MPa, the temperature at each sample position was raised to 160 ° C and left for 1 hour. The temperature variation between products in this process was ± 3 ° C. Thereafter, the inside of the autoclave was depressurized to foam the PET resin layer. The obtained foam was carefully peeled from the high thermal conductor (copper plate), and the foam cell diameter and reflectance were measured. The results are shown in Table 2.

 [0047] Example 2

 A foam was obtained in the same manner as in Example 1 except that the autoclave was installed in a thermostatic bath set at 160 ° C instead of adjusting the temperature of the heater in the sample place. The temperature variation between products in the carbon dioxide impregnation process was ± 25 ° C. Table 2 shows the evaluation results.

[0048] Example 3

In the same manner as in Example 1, without changing the copper plate 1 in FIG. 2 (a), 25 PET resin layers were formed on the entire surface of the copper plate and placed in an autoclave. Next, the autoclave was placed in a thermostatic layer, the temperature of the thermostat was raised to 160 ° C while maintaining the pressure of carbon dioxide and carbon dioxide at 15 MPa, and left for 1 hour (the autoclave heater was used during this time). Natsu ) In this process, the temperature variation between products is ± 5. It was within C. After that, the pressure was quickly released to normal pressure, and the PET resin layer was foamed. The obtained foam was carefully peeled from the copper plate, and the foam cell diameter and reflectance were measured. The results are shown in Table 2.

[0049] Example 4

 The PESF film was thermoformed on the entire copper plate as it was without breaking apart the copper plate 1 in Fig. 2 (a), and 25 PESF resin layers were formed and installed in the autoclave (film thickness; approx. 250 m). Next, the autoclave was placed in a thermostat set at 40 ° C., carbon dioxide was introduced, the pressure was increased to 15 MPa, and the mixture was allowed to stand for 2 hours. Thereafter, the inside of the autoclave was depressurized and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a surface heater set at 190 ° C for 1 minute to foam PESF resin. The temperature rise rate of the resin layer when the copper plate was in contact with the heater on the surface was 100 ° CZ or more even at the lowest, depending on the location. The obtained foam was carefully peeled from the copper plate, and the foam cell diameter and the reflectance were measured. The results are shown in Table 2.

[0050] Example 5

 Fig. 2 (a) Copper plate 1 is not broken apart. The special PC is dissolved and applied in tetrahydrofuran at a concentration of about 20% by weight on the entire surface of the copper plate. A layer was formed (film thickness; about 200; ζ ΐη). Next, it was placed in an autoclave, placed in a thermostatic chamber set at 40 ° C., carbon dioxide was introduced, and the pressure was increased to 15 MPa. After leaving for 2 hours, the pressure in the autoclave was released, and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a planar heater set at 270 ° C for 1 minute to foam special PC resin. The temperature rise rate of the resin layer when the copper plate was in contact with the surface heater varied depending on the location, but at least 100 ° CZ min or more. The obtained foam was carefully peeled from the copper plate, and the foam cell diameter and the reflectance were measured. The results are shown in Table 2.

[0051] Example 6

 A foam was obtained in the same manner as in Example 5 except that the set temperature of the planar heater was 200 ° C. Table 2 shows the evaluation results.

[0052] Example 7

A foam was obtained in the same manner as in Example 5 except that the set temperature of the planar heater was 140 ° C. . Table 2 shows the evaluation results.

[0053] Comparative Example 1

 A foam was obtained in the same manner as in Example 5 except that the set temperature of the planar heater was 330 ° C. Table 2 shows the evaluation results.

[0054] Comparative Example 2

 The same operation as in Example 5 was performed except that the set temperature of the planar heater was set to 100 ° C. However, there was almost no foaming power. The appearance was transparent and the reflectivity was judged to be very low, and no further evaluation was made.

[0055] Comparative Example 3

 A foam was obtained in the same manner as in Example 6 except that the copper plate was placed in a thermostat set to 200 ° C. instead of contacting the sheet heater. Table 2 shows the evaluation results. The temperature rising rate of the resin layer in the thermostatic chamber varied depending on the location, and was 30 to 70 ° CZ.

[0056] Example 8

 A foam was obtained in the same manner as in Example 6 except that the pressure after introduction of carbon dioxide was 5 MPa. The results are shown in Table 2.

[0057] Example 9

 In Fig. 2 (a), the copper plate 1 is not disassembled, but the special PI is dissolved in N-methyl 2-pyrrolidone at a concentration of about 15% by weight and applied to the entire surface of the copper plate. A special PI resin layer was formed (film thickness: approx. 200 m). Next, it was placed in an autoclave and placed in a thermostatic chamber set at 40 ° C. Carbon dioxide was introduced and the pressure was increased to 15 MPa. After leaving it for 2 hours, the inside of the autoclave was depressurized, and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a planar heater set at 200 ° C for 1 minute to foam special PI resin. The temperature rise rate of the resin layer when the copper plate was brought into contact with the heater on the surface was at least 100 ° CZ min. The obtained foam was carefully peeled from the copper plate, and the foam cell diameter and the reflectance were measured. The results are shown in Table 2.

[0058] Example 10

By pressing and curing SRC at 150 ° C and lOMPa for 15 minutes on the entire surface of the copper plate without breaking apart the copper plate 1 in Fig. 2 (a), and then heat-treating at 150 ° C for 30 minutes, 25 A piece of thermoset silicone resin layer was formed (film thickness; approximately 300 m). Next, it was placed in an autoclave, placed in a thermostatic chamber set at 40 ° C., carbon dioxide was introduced, and the pressure was increased to 15 MPa. After leaving it for 2 hours, the inside of the autoclave was depressurized and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a planar heater set at 200 ° C. for 1 minute to foam the silicone resin. The temperature rise rate of the resin layer when the copper plate was in contact with the surface heater varied depending on the location, but it was at least 100 ° CZ min. The obtained foam was carefully peeled from the copper plate, and the foam cell diameter and the reflectance were measured. The results are shown in Table 2.

[0059] Comparative Example 4

 Fig. 2 (a) Copper plate 1 is not broken apart, and the PEEK film is thermoformed at 380 on the entire surface of the copper plate, and then placed in a 25 ° C water bath to form 25 amorphous PEEK resin layers. (Film thickness; about 150 m). Next, it was placed in an autoclave, placed in a constant temperature bath set at 40 ° C, and carbon dioxide was introduced and the pressure was increased to 15 MPa. After leaving it for 2 hours, the inside of the autoclave was depressurized and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a planar heater set at 120 ° C for 1 minute to foam amorphous PEEK resin. The rate of temperature rise of the resin layer when the copper plate was brought into contact with the surface heater was at least 100 ° CZ min at least, although it varied depending on the location. The obtained foam was carefully peeled off from the copper plate, and the foam cell diameter and reflectivity were measured. The results are shown in Table 2.

[0060] Example 11

 Fig. 2 (a) copper plate 1 is not disassembled, and PMMA is dissolved and applied in black mouth form at a concentration of about 15% by weight on the entire surface of the copper plate. (Film thickness; about 200 m). Next, it was placed in an autoclave, placed in a thermostatic chamber set at 40 ° C., carbon dioxide was introduced, and the pressure was increased to 15 MPa. After leaving it for 2 hours, the inside of the autoclave was depressurized and the copper plate 1 was taken out under atmospheric pressure. After 5 minutes, the copper plate was brought into contact with a planar heater set at 90 ° C for 1 minute to foam PMMA resin. The temperature rise rate of the resin layer when the copper plate was in contact with the surface heater was at least 100 ° CZ min. The obtained foam was carefully peeled off from the copper plate, and the foam cell diameter and reflectance were measured. The results are shown in Table 2.

[0061] Example 12 Prepare four copper plates as shown in Fig. 2 (a). Dissolve and apply special PC in tetrahydrofuran at a concentration of about 20% by weight on the entire surface of each copper plate, and then evaporate the solvent to form a special PC resin layer. (Film thickness; approx. 200 m). Next, the four resin layers were peeled off from each copper plate and placed in an autoclave. Then, carbon dioxide was introduced at room temperature and the pressure was increased to 5 MPa. After leaving it for 2 hours, the pressure inside the autoclave was released, and the four resin layers were taken out under atmospheric pressure. Due to gas impregnation at room temperature, the temperature unevenness at this time was extremely small ± 1 ° C. After 5 minutes, four resin layers were arranged in series, and a planar heater set at 200 ° C was brought close to a distance of 5 cm and left for 1 minute to foam special PC resin. The temperature rising rate of the resin layer at this time was different depending on the location, but it was at least 100 ° CZ min. The obtained foam was divided into 100 products, and the foam cell diameter and reflectance were measured. The results are shown in Table 2.

[0062] Comparative Example 5

 A sheet of PAZTiO resin composition was prepared by compression molding at 360 ° C. Sheet reflectivity

 2

 Table 2 shows the measurement results.

[0063] Comparative Example 6

 A sheet of PAZ potassium titanate resin composition was formed by compression molding at 360 ° C. Table 2 shows the measurement results of the sheet reflectivity.

[0064] [Table 1]

Sample Gas permeation condition of tree layer for each product Foaming condition

 Metal plate

 Type Td CC) λ 50 (nm) Temperature control Formation method Pressure (MPa) Temperature (in) Temperature unevenness (in) Temperature increase rate (in / min) S degree (C) Heating case Example 1 PET 390 320 Discontinuous Consistent Compression molding 15 160 ± 3 160-Example 2 PET 390 320 Discontinuity None Compression molding 15 160 ± 25-160 One Example 3 PET 390 320 Continuous None Compression molding 15 160 ± 5-160 One Example 4 PESF 481 336 Continuous None Thermoforming 15 40 ± 2 ≥100 190 Planar heater (contact) Example 5 Special PC 467 2Θ6 Continuous None Solvent cast 15 40 ± 2 270 Planar heater (contact) Example 6 Special PC 467 2Θ6 Continuous None Solvent text 15 40 ± 2> 100 200 Planar heater (contact) Example 7 Special PC 467 296 Continuous None Solvent cast 15 40 ± 2> 100 140 Planar heater (<0 Comparative example 1 Special PC 467 296 ½fe None Solvent cast 15 40 ± 2> 100 330 Sheet heater (Contact) Comparative example 2 Special PC 467 296 j Vt None Solvent cast 15 40 ± 2> 100 100 Planar!:-T (Contact ») Comparative Example 3 Special PC 467 296 Continuous None Solvent cast 15 40 ± 2 30-70 200 Thermostatic chamber Example 8 Special PC 467 296 Rapid None Minato cast 5 40 ± 2 Fan 200 Planar heater (contact) Implementation Example 9 Special PI 370 361 Series None Solvent cast 15 40 ± 2 Recommended 200 Planar heater (contact) Example 10 SRC 335 288 Rapid sequence None Mature curing 15 40 ± 2> 100 200 Planar heater (contact) Comparative Example 4 Amorphous PEEK 550 412 Continuous None ft molding 15 40 ± 2> 100 120 Planar heater (contact) Example 1 1 290 285 Continuous None Solvent text 15 40 ± 2 Fan 90 Planar Heater (contact) Example 12 Special PC 467 296 None None Solvent cast 5 Room temperature ± 1 ≥100 200 Planar t-ta (Approach: 5cm) Comparative example 5 PA / Ti02--Compression molding 1----

PA / titanic acid

Comparative Example 6--Compression molding

Potassium fiber-----

Table 2]

As shown in Table 2, the number average cell diameter (μm) is 50 μm or less for a resin whose wavelength is 4 OOnm or less, which reduces the light transmittance to 50% at an optical path length of 250 m. When foamed, the reflectivity at 380 nm was 80% or higher. In addition, when a resin having a thermal decomposition temperature of 300 ° C or higher was used, a decrease in reflectance at 550 nm due to heat treatment could be suppressed. Ga When the permeation temperature unevenness is controlled to be within ± 20 ° C between products, or when the heating rate during heating and foaming is controlled to 50 ° CZ or more, the reflectance between products at 380 nm The variation in the range was reduced to within ± 5%.

Industrial applicability

 The LED reflector of the present invention can be used for various office automation equipment, electrical and electronic equipment and parts, automobile parts, and the like such as displays, destination display boards, in-vehicle lighting, signal lights, emergency lights, mobile phones, and video cameras.

Claims

The scope of the claims  [1] Wavelength power of light that reduces the light transmittance to 50% at an optical path length of 250 m, or a resin composition having a number average foamed cell diameter of 50 m or less LED reflector made of  [2] The resin or the resin composition according to claim 1, wherein the resin has a 5% weight loss temperature of 300 ° C or higher. LED reflector.  [3] The method for producing a reflector for LED according to claim 1 or 2, wherein a foam is produced by allowing gas to penetrate into the resin or the resin composition and then degassing. 4. The method for producing a reflector for an LED according to claim 3, wherein the resin or the resin composition is foamed in the process of allowing gas to penetrate into the resin or resin composition under pressure and then returning to normal pressure. [5] The LED reflector according to claim 3, wherein the resin or resin composition impregnated with gas is foamed in the process of heating the resin or resin composition at a temperature rising rate of 50 ° CZ or more. Manufacturing method. 6. The method for producing a reflector for LED according to claim 5, wherein the temperature of the resin or resin composition impregnated with gas is increased by bringing the resin or resin composition closer to a planar heater within 20 cm. [7] The molded body made of a plurality of greaves or rosin compositions is placed in a pressure vessel, and gas is permeated into the molded body while controlling temperature unevenness between the molded bodies within ± 20 ° C. 3 ~ 6. The method for producing a reflector for an LED according to claim 1. [8] A claim for producing a foam by impregnating gas into a resin or resin composition layer comprising a resin or resin composition formed on a continuous metal plate in advance and then degassing it. Item 8. A method for producing a reflector for LED according to any one of Items 3 to 7.