JP2013209609A - Heat conductive resin composition for led illumination substrate, method for manufacturing the same, and led illumination substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat conductive resin composition for LED illumination substrate, capable of improving heat conductivity and insulating properties regardless of the large amount of inorganic filler, such as magnesium oxide.SOLUTION: In a heat conductive resin composition for LED illumination substrate containing a resin and inorganic filler, the inorganic filler contains at least a magnesium oxide, the content of the inorganic filler is ≥50 vol.% and <95 vol.% based on the total amount of the heat conductive resin composition for LED illumination substrate. A weight increasing ratio is <5% after a cured product of the heat conductive resin composition for LED illumination substrate being left for 500 hours under an atmosphere at 85°C of a temperature and 85% of relative humidity.

Description

  TECHNICAL FIELD The present invention relates to a thermally conductive resin composition for an LED illumination substrate used for an LED illumination substrate, a method for producing the same, and an LED illumination substrate.

  Semiconductors such as computers (CPUs), transistors, and light emitting diodes (LEDs) generate heat during use, and the performance of electronic components may deteriorate due to the heat. Therefore, a heat radiator is attached to an electronic component that generates heat. Conventionally, a metal having high thermal conductivity has been used for such a heat radiating body, but in recent years, a thermal conductive resin composition having a high degree of freedom in shape selection and being easy to be reduced in weight and size has been used. (For example, refer to Patent Documents 1 and 2). In such a thermally conductive resin composition, a large amount of an inorganic filler having thermal conductivity must be blended in the resin in order to improve thermal conductivity. However, it is known that various problems arise when the amount of the inorganic filler is simply increased. For example, since there are many compounding quantities of an inorganic filler, the heat conductive resin composition before hardening becomes high-viscosity, a moldability and workability | operativity fall significantly and will cause a molding defect. Moreover, there is a limit to the filling amount of the inorganic filler, and in many cases, sufficient thermal conductivity cannot be obtained.

JP 2003-321611 A Japanese Patent No. 4514164

  As a method of filling a large amount of inorganic filler into a resin, a method using a combination of inorganic fillers having different particle diameters, a method using a combination of inorganic fillers having different shapes, and silane coupling when mixing inorganic filler and resin A method of adding a surface treatment agent such as an agent is conceivable.

  The above method is effective from the viewpoint of filling the inorganic filler 2 in the resin 1 at a high concentration. However, as shown in FIG. 2A, only kneading is performed using a stirrer (for example, a kneader, a three-roller, a planetary mixer, etc.) provided with a container 7 having a blade 6 for stirring. . Therefore, depending on the type of the inorganic filler 2 to be used, the inorganic filler 2 is broken or broken in the dispersion step of the resin 1 and the inorganic filler 2 as shown in FIG. 2B. In particular, when both the blade 6 and the container 7 are made of metal, a strong shearing force is generated between the blades 6 and between the blade 6 and the inner surface of the container 7, and the inorganic filler 2 is destroyed by this shearing force. It becomes easy. And as shown in FIG.2 (b), when the inorganic filler 2 is destroyed, since the active surface 9 will arise, a water | moisture content etc. will adsorb | suck to this active surface 9 easily. In particular, the inorganic filler 2 that is easily hydrolyzed by water such as magnesium oxide is hydrolyzed by the water adsorbed on the active surface 9 and denatured. Therefore, about the hardened | cured material of the conventional heat conductive resin composition 10, the problem arises in the long-term reliability (especially heat conductivity and insulation) under high temperature and high humidity.

  The present invention has been made in view of the above points, and even when the content of an inorganic filler such as magnesium oxide is large, the heat conductive resin composition for an LED lighting substrate that can improve the thermal conductivity and the insulating property. It is an object of the present invention to provide an object, a manufacturing method thereof, and an LED lighting substrate.

  The thermally conductive resin composition for an LED lighting board according to the present invention is a thermally conductive resin composition for an LED lighting board containing a resin and an inorganic filler, wherein the inorganic filler contains at least magnesium oxide, The content is 50% by volume or more and less than 95% by volume with respect to the total amount of the heat conductive resin composition for LED lighting substrate, and the cured product of the heat conductive resin composition for LED lighting substrate has a temperature of 85 ° C. and a relative humidity. The weight increase rate after being left in an 85% atmosphere for 500 hours is less than 5%.

  In the thermally conductive resin composition for an LED lighting substrate, the resin preferably contains at least one of an unsaturated polyester resin and an epoxy acrylate resin.

  In the thermally conductive resin composition for LED lighting substrate, the thermally conductive resin composition for LED lighting substrate further contains a flame retardant, the resin contains an epoxy acrylate resin, and the flame retardant is a bromine-containing epoxy. It is preferable to contain at least one of a compound and a bromine-containing acrylic compound.

  In the heat conductive resin composition for LED lighting substrate, the flame retardant further contains antimony trioxide, and the content of bromine element in the heat conductive resin composition for LED lighting substrate is 1.0 atm. It is preferable that the molar ratio of the bromine element and the antimony element is 3: 1 to 3: 5.

  The method for producing a thermally conductive resin composition for an LED lighting substrate according to the present invention comprises a step of mixing a resin and an inorganic filler with a stirring blade so that the content of the inorganic filler is 50% by volume or more and less than 95% by volume. A first step of obtaining a dispersion in which the resin and the inorganic filler are dispersed by rotating and revolving the nonmetallic container in a nonmetallic container that does not have, and a blade for stirring the dispersion The second step of redispersing the resin and the inorganic filler is performed in this order by rotating the blade in a container having the above.

  The LED illumination board according to the present invention is characterized in that an LED light emitting portion is provided on a substrate obtained by curing the heat conductive resin composition for an LED illumination board.

  According to the thermally conductive resin composition for an LED lighting substrate according to the present invention, even if the content of an inorganic filler such as magnesium oxide is large, the adsorption of moisture or the like to the inorganic filler is suppressed. And the insulating property can be improved.

  According to the method for producing a thermally conductive resin composition for an LED lighting substrate according to the present invention, the inorganic filler is stirred with the stirring blade in the first step even if the content of the inorganic filler such as magnesium oxide is large. Since the inorganic filler is less likely to be destroyed and the adsorption of moisture and the like to the inorganic filler is suppressed, the thermal conductivity and insulation can be improved, and by using a non-metallic container in the first step Coloring can also be reduced.

  According to the LED lighting board according to the present invention, even when the content of the inorganic filler such as magnesium oxide is large, the thermal conductivity and the insulation can be improved.

An example of the manufacturing method of the heat conductive resin composition for LED lighting substrates which concerns on this invention is shown notionally, (a)-(c) is explanatory drawing. An example of the manufacturing method of the conventional heat conductive resin composition is shown notionally, (a) (b) is explanatory drawing.

  Embodiments of the present invention will be described below.

  The heat conductive resin composition 3 for an LED lighting board according to the present invention contains a resin 1 and an inorganic filler 2.

  The resin 1 preferably contains at least one of an unsaturated polyester resin and an epoxy acrylate resin which are thermosetting resins. That is, as the resin 1, either one of an unsaturated polyester resin or an epoxy acrylate resin may be used, or a mixture of both may be used. Further, a resin 1 other than these resins 1 may be contained.

  The unsaturated polyester resin and the epoxy acrylate resin are low-viscosity liquids before the curing reaction. Therefore, it is easy to highly fill these resins with the inorganic filler 2, and the heat conductive resin composition 3 for an LED lighting substrate can be easily manufactured. In addition, since these resins form a three-dimensional cross-linked structure after the curing reaction, when used as a material for an LED lighting substrate, there is no risk of melting due to heat generated by the LED light emitting portion, and high reliability can be obtained.

  The type of unsaturated polyester resin is not particularly limited. The unsaturated polyester resin contains, for example, an unsaturated polybasic acid such as an unsaturated dicarboxylic acid (added with a saturated polybasic acid as necessary), a polyhydric alcohol, and a crosslinking agent such as styrene. The unsaturated polybasic acid and the saturated polybasic acid include acid anhydrides.

  Examples of the unsaturated polybasic acid include unsaturated dibasic acids such as maleic anhydride, maleic acid, fumaric acid, and itaconic acid. Examples of the saturated polybasic acid include dibasic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, and sebacic acid, benzoic acid, and trimellitic acid. Examples include acids other than basic acids.

  Examples of the polyhydric alcohol include glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, hydrogenated bisphenol A, and 1,6-hexanediol.

  As the crosslinking agent, generally, an unsaturated monomer that can be crosslinked with a thermosetting resin that is a condensation polymerization product of an unsaturated polybasic acid and a polyhydric alcohol can be used. The unsaturated monomer is not particularly limited, and examples thereof include styrene monomers, vinyl toluene, vinyl acetate, diallyl phthalate, triallyl cyanurate, acrylic acid ester, methyl methacrylate, and ethyl methacrylate. Methacrylic acid esters and the like can be used.

  After reacting the unsaturated polybasic acid and the polyhydric alcohol by a known polycondensation reaction, radical polymerization is performed using a crosslinking agent to obtain an unsaturated polyester resin that is a thermosetting resin. Can do. Representative examples of such unsaturated polyester resins include maleic anhydride-propylene glycol-styrene.

  As a method for curing the unsaturated polyester resin, a known method can be used. For example, a curing agent such as a radical polymerization initiator is added and heated as necessary or irradiated with active energy rays. Just do it. As the curing agent, known ones can be used, for example, peroxydicarbonates such as t-amyl peroxyisopropyl carbonate, ketone peroxides, hydroperoxides, diacyl peroxides, peroxyketals. , Dialkyl peroxides, peroxyesters, alkyl peresters and the like. These may be used alone or in combination of two or more.

  On the other hand, the epoxy acrylate resin is a resin having a functional group capable of undergoing a polymerization reaction on the epoxy resin skeleton. Specifically, an epoxy acrylate resin has an unsaturated monobasic acid such as acrylic acid or methacrylic acid or an unsaturated group such as maleic acid or fumaric acid, on the epoxy group of an epoxy resin having two or more epoxy groups in one molecule. It is a reaction product obtained by ring-opening addition of a monoester of a saturated dibasic acid. Usually, this reaction product is in a liquid resin state by a diluent. Examples of the diluent include radical polymerization reactive monomers such as styrene, methyl methacrylate, ethylene glycol dimethacrylate, vinyl acetate, diallyl phthalate, triallyl cyanurate, acrylic ester, and methacrylic ester. It is done.

  Here, examples of the epoxy resin skeleton include known epoxy resins, and specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin or bisphenol synthesized from bisphenol A, bisphenol F or bisphenol S and epichlorohydrin. Bisphenol type epoxy resin such as S type epoxy resin, so-called phenol novolac resin obtained by reacting phenol and formaldehyde in the presence of an acidic catalyst, phenol novolac type epoxy resin synthesized from epichlorohydrin, and cresol and formaldehyde in the presence of an acidic catalyst And a so-called cresol novolac resin obtained from the above and a novolac epoxy resin such as a cresol novolac type epoxy resin synthesized from epichlorohydrin.

  As a method of curing the above epoxy acrylate resin, the same method as the above unsaturated polyester resin can be used. By using the same curing agent as the above, curing of the epoxy acrylate resin can be performed. You can get things.

The inorganic filler 2 contains at least magnesium oxide (MgO). The inorganic filler 2 may be magnesium oxide alone, but when other inorganic fillers 2 are also used, for example, boron nitride (BN), aluminum hydroxide (Al (OH) ₃ ), mica, or the like can be used.

  In particular, as magnesium oxide, it is preferable to use dead-burned magnesia (hard-burned magnesia, heavy-burned magnesia) produced by a dead-burning baking method with low surface activity in order to prevent hydrolysis due to moisture. Light-burned magnesia (calcined magnesia) is fired at 1200 ° C. or lower during production, whereas dead-burned magnesia is fired at a high temperature of 1500 ° C. or higher. Therefore, dead-burned magnesia has better moisture resistance due to fewer pores and lower surface activity.

  Furthermore, as magnesium oxide, it is preferable to mix and use two types having different median diameters. Thus, by mix | blending what has a different median diameter, the viscosity increase of resin can be suppressed and a lot of inorganic fillers 2 can be mix | blended in resin. For example, it is preferable to mix the median diameter of 30 to 200 μm (more preferably 50 to 150 μm) and 1 to 20 μm (more preferably 5 to 10 μm). Furthermore, it is preferable that these compounding ratios (mass ratio) are 90: 10-10: 90, and it is more preferable that it is 70: 30-30: 70. The median diameter means a particle diameter (d50) at which an integrated (cumulative) weight percentage is 50%, and can be measured using a laser diffraction particle size distribution measuring apparatus.

  Content of the inorganic filler 2 is 50 volume% or more and less than 95 volume% with respect to the heat conductive resin composition 3 for LED lighting boards. Here, the content of the inorganic filler 2 means the content of magnesium oxide when only magnesium oxide is used, and the content of magnesium oxide and the other inorganic filler 2 as a whole when other inorganic fillers 2 are also used. Means quantity. When the inorganic filler 2 other than magnesium oxide is also used, the content of magnesium oxide is 40% by volume or more. When the content of the inorganic filler 2 is less than 50% by volume, it is impossible to achieve high thermal conductivity of the cured product of the LED lighting substrate heat conductive resin composition 3. When the content of the inorganic filler 2 is 95% by volume or more, the heat conductive resin composition 3 for an LED lighting substrate cannot be molded.

  In particular, when the resin 1 contains an epoxy acrylate resin, it is preferable that the thermally conductive resin composition 3 for an LED lighting substrate further contains a flame retardant. Thereby, the flame retardance of hardened | cured material can be improved. And it is preferable that the flame retardant in said case contains at least 1 sort (s) of a bromine containing epoxy compound and a bromine containing acrylic compound. That is, the flame retardant may contain either a bromine-containing epoxy compound or a bromine-containing acrylic compound, or may contain a mixture of both. Such a flame retardant has a functional group that reacts with and binds to the resin 1 and is incorporated into the resin skeleton during the curing reaction of the resin 1, thereby suppressing a decrease in the mechanical strength of the cured product. It can be done.

  Examples of the bromine-containing epoxy compound include brominated epoxy (ICL-IP JAPAN “F-2001”, “F-2200”, etc.), polybrominated epoxy (ICL-IP JAPAN) “F-2016”, “F-2300”, “F-2310”, “YDB-400”, “YDB-405” manufactured by Nippon Steel Chemical Co., Ltd., “EPICLON 152”, “EPICLON” manufactured by DIC Corporation 153 "etc.).

  Examples of the bromine-containing acrylic compound include pentabromobenzyl acrylate (“FR-1025M” manufactured by ICL-IP JAPAN) and polypentabromobenzyl acrylate (“FR-1025” manufactured by ICL-IP JAPAN). Etc.).

The flame retardant, at least one other bromine-containing epoxy compounds and bromine-containing acrylic compound, preferably further contains a antimony trioxide (Sb 2 _{O 3).} The flame retardancy of the cured product can be further improved by a synergistic effect of the antimony trioxide and at least one of the bromine-containing epoxy compound and bromine-containing acrylic compound.

  When the flame retardant contains antimony trioxide, the content of elemental bromine in the thermally conductive resin composition 3 for LED lighting substrate is 1.0 atm. % (Upper limit is 2.0 atm.%), And the molar ratio of bromine element to antimony element is preferably 3: 1 to 3: 5. Thereby, the flame retardance of hardened | cured material can further be improved.

  The flame retardant may contain a flame retardant other than the bromine-containing epoxy compound, bromine-containing acrylic compound and antimony trioxide. Examples of such flame retardants include bromine-containing styrene compounds, decabromodiphenyl ether, and tetrabromobisphenol-A.

  Examples of the bromine-containing styrene compound include brominated styrene, brominated polystyrene ("SAYTEX HP-7010", "SAYTEX HP-3010" manufactured by Albemarle Japan Co., Ltd.), "Great Lakes pdbs manufactured by Chemtura Japan Co., Ltd." -80 "," Great Lakes PBS-64HW ", etc.).

  However, although decabromodiphenyl ether and tetrabromobisphenol-A can impart flame retardancy to the cured product, they are difficult to be incorporated into the resin skeleton during the curing reaction of the resin 1, so that the mechanical strength of the cured product is reduced. There is a risk of causing. Since antimony trioxide is not easily incorporated into the resin skeleton, for example, when used in combination with antimony trioxide and decabromodiphenyl ether, the mechanical strength of the cured product may be extremely reduced. Furthermore, tetrabromobisphenol-A traps radicals generated during the curing reaction of the resin 1, which may inhibit the curing reaction of the resin 1 and cause defective molding.

  And the heat conductive resin composition 3 for LED lighting board | substrates is a flame retardant, a diluent, a polymerization inhibitor, a viscosity regulator, a hardening | curing agent, and mold release as needed other than said resin 1 and the inorganic filler 2. You may contain other components, such as an agent. As the diluent, for example, styrene or the like can be used. As a polymerization inhibitor, p-benzoquinone etc. can be used, for example. As the mold release agent, for example, zinc stearate and stearic acid can be used.

  The heat conductive resin composition 3 for an LED lighting board according to the present invention can be manufactured by going through the first step shown in FIG. 1 (a) and the second step shown in FIG. 1 (b) in this order. it can.

  In the first step, as the stirrer, a non-metallic container 4 having no stirring blade 6 is formed so as to be capable of rotating and revolving. The blade 6 includes, for example, a rod shape, a plate shape, a blade shape, a wing shape, a propeller shape, and the like, but such a blade 6 is not provided in the stirrer used in the first step. As such a stirrer, for example, “Planet-type stirring and deaerator MAZERSTAR KK-1000W” manufactured by Kurashiki Boseki Co., Ltd. can be used. It is preferable that at least the inner surface of the non-metallic container 4 is made of resin such as polypropylene, ceramic, or glass. The rotation axis 8 of the non-metallic container 4 is normally in the vertical direction, but may be inclined with respect to the vertical direction as long as the contents do not spill. And as shown to Fig.1 (a), said resin 1, the inorganic filler 2, and other components are said non-metal so that content of the inorganic filler 2 may be 50 volume% or more and less than 95 volume%. After putting in the container 4, the non-metallic container 4 is rotated (for example, rotation speed 20 to 800 rpm) and revolved (for example, rotation speed 130 to 800 rpm) for 1 to 5 minutes, for example, resin 1 and inorganic filler 2. A dispersion 5 in which is preliminarily dispersed can be obtained. In the first step, the non-metallic container 4 itself containing the resin 1 and the inorganic filler 2 can be subjected to a planetary motion so that a shearing force can be applied to the contents. Even without using, effects such as stirring, kneading and defoaming can be obtained. Thus, since the resin 1 and the inorganic filler 2 are not stirred and dispersed by the stirring blade 6, the inorganic filler 2 is less likely to be destroyed and the active surface 9 is less likely to be generated, thereby adsorbing moisture and the like. It can be suppressed. Moreover, since the resin 1 and the inorganic filler 2 are agitated and dispersed while being in contact with the non-metallic surface of the inner surface of the non-metallic container 4, the metal fine particles are less likely to be mixed, reducing the coloration or suppressing the deterioration of the insulating property. Is something that can be done.

  Next, in the second step, a stirrer equipped with a container 7 having a stirring blade 6 is used. As such a stirrer, for example, a kneader such as “Pressure Type Kneader TD3-10MDX” manufactured by Toshin Co., Ltd. or a planetary mixer such as “TK Hibismix 2P-1 Model” manufactured by Primex Corporation is used. be able to. The kneader usually has two blades 6 and generates a shearing force between these blades 6 and between the blades 6 and the inner surface of the container 7, and kneading, kneading, pulverizing, dispersing, etc. by this shearing force. The effect is obtained. In addition, the planetary mixer usually has two blades 6, but these blades 6 perform planetary motion, and the planetary motion causes shearing force between these blades 6 and between the blade 6 and the inner surface of the container 7. This shearing force provides effects such as stirring, kneading, and dispersion. The stirrer blade 6 used in the second step includes, for example, rods, plates, blades, wings, propellers, and the like. The material and number of the blades 6 are not particularly limited. In this case, at least the inner surface of the container 7 is preferably made of resin such as polypropylene, ceramic or glass, but may be made of metal.

  And as shown in FIG.1 (b), when using a kneader, for example as a stirrer, after putting said dispersion | distribution 5 in said container 7, the blade 6 is rotated (for example, for 5 to 20 minutes, for example). By rotating the resin 10 and the inorganic filler 2 and the like again, a thermally conductive resin composition 3 for an LED lighting substrate as shown in FIG. 1C can be obtained.

  For example, when a planetary mixer is used as a stirrer, the blade 5 is rotated (for example, a revolution speed of 10 to 100 rpm and a rotation speed) for 5 to 20 minutes after the dispersion 5 is put in the container 7. 20 to 240 rpm), and the resin 1 and the inorganic filler 2 are dispersed again to obtain the heat conductive resin composition 3 for an LED lighting substrate as shown in FIG.

  Since the powdery dispersion 5 cannot be made into the clay-like dispersion 5 only by the first step, the second step is necessary after the first step. Conversely, since the inorganic filler 2 is easily destroyed as in the prior art only in the second step, the resin 1 and the inorganic filler 2 and the like are dispersed to a certain extent while suppressing the destruction of the inorganic filler 2 before the second step. One step is required. In the second step, the dispersion 5 is directly dispersed by the blade 6, but since the resin 1 and the inorganic filler 2 are uniformly mixed in the first step to some extent, the time required for the second step is: This can be shortened compared to the case of only the second step (when there is no first step). Therefore, even if there is a second step after the first step, the destruction of the inorganic filler 2 is not particularly problematic.

  And when the heat conductive resin composition 3 for LED lighting boards obtained as mentioned above is arrange | positioned to a predetermined metal mold | die and it heat-presses and shape | molds, the resin 1 will be melt-softened by this heat pressurization, and predetermined | prescribed A molded product (cured product) can be manufactured by deforming into a shape and curing. An LED illumination substrate (not shown) can be formed by using the molded product thus obtained as a substrate and providing an LED light emitting portion on the substrate. In addition, although the molding conditions for obtaining a molded product are not specifically limited, For example, a molding temperature of 120 to 160 ° C., a molding pressure of 5 to 30 MPa, and a molding time of 3 to 10 minutes can be set.

  The weight gain after the cured product obtained as described above is allowed to stand for 500 hours in an atmosphere having a temperature of 85 ° C. and a relative humidity of 85% is less than 5%. Thus, although the content of the inorganic filler 2 such as magnesium oxide is large, the amount of water absorption of the cured product after the moisture resistance test (high temperature and high humidity test) is low because of the stirring blade in the first step. This is because the resin 1 and the inorganic filler 2 are dispersed by the rotation and revolution of the non-metallic container 4 regardless of 6. That is, with such a dispersion, the inorganic filler 2 is not easily destroyed and the active surface 9 is not easily generated, so that adsorption of moisture and the like to the inorganic filler 2 is suppressed, and thereby long-term reliability (particularly thermal conductivity and (Insulating property) can be improved. In addition, by using the non-metallic container 4 in the first step, it is difficult for metal fine particles to be mixed in, and it is possible to reduce coloring or suppress deterioration of insulation.

  Hereinafter, the present invention will be specifically described by way of examples.

  The following thermosetting resins, diluents, polymerization inhibitors, viscosity modifiers, curing agents, mold release agents, inorganic fillers, and flame retardants were used in producing the LED lighting substrate heat conductive resin composition.

(Thermosetting resin)
Epoxy acrylate resin (“Neopol 8250H”, manufactured by Nippon Iupika Co., Ltd.)
Unsaturated polyester resin ("M-640LS" manufactured by Showa Polymer Co., Ltd.)
(Diluent)
Styrene (polymerization inhibitor)
p-Benzoquinone (viscosity modifier)
"BYK9010" manufactured by Big Chemie Japan
(Curing agent)
t-amyl peroxyisopropyl carbonate (release agent)
Zinc stearate stearic acid (inorganic filler)
Magnesium oxide (MgO, median diameter 90 μm)
Magnesium oxide (MgO, median diameter 5 μm)
Boron nitride (BN, median diameter 8.5 μm)
Aluminum hydroxide (Al (OH) ₃ , median diameter 35 μm)
Mica (median diameter 30μm)
The median diameter means a particle diameter (d50) at which the cumulative (cumulative) weight percentage is 50%, and is measured using a laser diffraction particle size distribution measuring apparatus “SALD2000” (manufactured by Shimadzu Corporation). be able to.

(Flame retardants)
Bromine-containing epoxy compound ("F-2200" manufactured by ICL-IP JAPAN Co., Ltd., which is brominated epoxy)
Bromine-containing acrylic compound ("FR-1025M" manufactured by ICL-IP JAPAN, a pentabromobenzyl acrylate)
Antimony trioxide (“PATOX-M” manufactured by Nippon Seiko Co., Ltd.)
(Examples 1-7, 9-12)
The heat conductive resin composition for LED lighting substrates was manufactured by going through the following first step and second step in this order (see FIG. 1).

  In the first step, a “planetary stirring and deaerator MAZERSTAR KK-1000W” manufactured by Kurashiki Boseki Co., Ltd. was used as a stirrer. And after putting a thermosetting resin, an inorganic filler, etc. in content shown in Table 1 and Table 2 in a nonmetallic container (polypropylene container), a nonmetallic container is rotated for 4 minutes (rotation speed of 400 rpm) and A dispersion was obtained by revolution (revolution speed 800 rpm).

  Next, in the second step, “Pressurized Kneader TD3-10MDX” manufactured by Toshin Co., Ltd. was used as a stirrer. And after putting said dispersion | distribution into the container of a stirrer, the blade was rotated for 5 minutes (rotation speed 30rpm), and the dispersion was again disperse | distributed, and the heat conductive resin composition for LED lighting boards was obtained. .

(Example 8)
A 1st process is the same as that of Examples 1-7 and 9-12.

  Next, in the second step, “TK Hibismix 2P-1” manufactured by Primix Co., Ltd. was used as a stirrer. And after putting said dispersion | distribution in the container of a stirrer, a blade is rotated (autorotation 50rpm, revolution 50rpm) for 5 minutes, and disperse | distributes dispersion again, The heat conductive resin composition for LED lighting boards is obtained. Obtained.

(Comparative Examples 1 and 3)
“Pressurized kneader TD3-10MDX” manufactured by Toshin Co., Ltd. was used as a stirrer. And after putting a thermosetting resin, an inorganic filler, etc. into the container of a stirrer with content shown in Table 2, the blade is rotated (rotation speed 30rpm) for 30 minutes, The heat conductive resin composition for LED lighting board | substrates I got a thing.

(Comparative Example 2)
As a stirrer, “TK Hibismix 2P-1 type” manufactured by Primix Co., Ltd. was used. And after putting thermosetting resin, an inorganic filler, etc. with the content shown in Table 2 in the container of a stirrer, by rotating a braid | blade for 20 minutes (autorotation 50rpm, revolution 50rpm), it is thermal conductivity for LED lighting board | substrates. A resin composition was obtained.

(Molding)
Each heat conductive resin composition for LED lighting substrates was placed in a mold composed of an upper mold and a lower mold and molded by heating and pressing. The molding conditions at this time were set to a molding temperature (mold temperature) of 145 ° C., a molding pressure of 7 MPa, and a molding time of 4 minutes. The thermosetting resin was melted and softened by the above heating and pressurization, deformed into a predetermined shape, and cured to produce a molded product.

(Quantification of volume ratio of inorganic filler)
Using X-ray photoelectron spectroscopic analysis ("ESCALAB220-XL" manufactured by Thermo Fisher Scientific Co., Ltd.), the analysis was performed by irradiating X-rays in the 1 mm square analysis area of the molded product. In the depth direction analysis, the surface of the molded product was cut by sputtering with argon ion irradiation, and then the analysis was performed in the deep part, and the element concentration (atm.%) Derived from the inorganic filler contained in the molded product at a specific depth was calculated. And the volume ratio of the inorganic filler (1) / (2) in the molded product is calculated from the element concentration ratio derived from the inorganic filler (1) (2) calculated by X-ray photoelectron spectroscopy and the density of each inorganic filler. Calculated. The results are shown in Table 3. In calculating the volume ratio, the density of magnesium oxide is 3.6 g / cm ³ , the density of boron nitride is 2.2 g / cm ³ , the density of aluminum hydroxide is 2.4 g / cm ³ , and the density of mica is 2 .9 g / cm ³ .

(Quantification of content of inorganic filler)
The volume of the molded product was calculated by the Archimedes method. Then, this molded product was fired at 625 ° C. using a muffle furnace, and the weight of the remaining ash was measured. Since ash is an inorganic filler, the content (volume percentage) of the inorganic filler contained in the molded product was calculated from the volume ratio of the inorganic filler and the density of each inorganic filler. The results are shown in Table 3.

(Quantification of bromine and antimony elements)
Using X-ray photoelectron spectroscopic analysis ("ESCALAB220-XL" manufactured by Thermo Fisher Scientific Co., Ltd.), the analysis was performed by irradiating X-rays in the 1 mm square analysis area of the molded product. In the depth direction analysis, the surface of the molded product is cut after sputtering by argon ion irradiation, and then analysis is performed in the deep part. The concentration of bromine element and antimony element derived from the flame retardant contained in the molded product at a specific depth (atm.%). ) Was calculated. Furthermore, the molar ratio of bromine element and antimony element was calculated from these element concentrations. The results are shown in Table 3.

(Measurement of weight increase rate)
A plate-shaped test piece having a size of 100 mm square and a thickness of 2.5 mm was cut out from the molded product, dried at 50 ° C. for 6 hours, and the weight of the test piece was measured. Next, a humidity resistance test (high temperature and high humidity test) was performed in which the test piece was placed in a constant temperature and humidity chamber having a temperature of 85 ° C. and a relative humidity of 85% and left for 500 hours. Thereafter, the weight of the test piece was measured, and the weight increase rate was calculated from the weight of the test piece before and after the test. The results are shown in Table 4.

(Measurement of thermal conductivity)
A 10 mm square and 2 mm thick test piece was cut out from the molded product, and the thermal conductivity of this test piece before and after the humidity resistance test (temperature 85 ° C., relative humidity 85%, 500 hours) was measured as xenon flash thermal conductivity manufactured by NETZSCH. It measured at 25 degreeC using the measuring apparatus "LFA447". The results are shown in Table 4.

(Measurement of dielectric breakdown strength)
A plate-shaped test piece of 100 mm square and a thickness of 2.5 mm was cut out from the molded product, and the dielectric breakdown before and after the moisture resistance test (temperature 85 ° C., relative humidity 85%, 500 hours) of this test piece based on JIS C2110-1. The strength was measured. That is, a voltage having a commercial frequency of 60 Hz was applied between the electrodes sandwiching the test piece in 23 ° C. silicone oil, and the voltage at which the sample piece was broken was determined. A short-time method (pressure increase rate: 1.5 kV / s) was adopted as a voltage application method, and a dielectric breakdown test apparatus “YST-243-100RHO” (manufactured by Yamayo Tester) was used as a tester. The results are shown in Table 4.

(Coloring)
The molded product was visually observed to check for coloring. The results are shown in Table 4.

(Measurement of bending strength)
A test piece having a length of 100 mm, a width of 10 mm, and a thickness of 4 mm was cut out from the molded product, and the bending strength of the test piece was measured based on JIS K7171. For this measurement, Autograph AG-X (manufactured by Shimadzu Corporation) was used, and measurement was performed under the conditions of a test speed of 2 mm / sec and a fulcrum distance of 64 mm. The results are shown in Table 4.

(Flame retardance)
A test piece having a length of 125 mm, a width of 13 mm, and a thickness of 2 mm was cut out from the molded product, and a flame test based on the UL94 standard was performed on the test piece to evaluate flame retardancy. The results are shown in Table 4 as “◎” (V-0 conforming), “◯” (V-1 conforming), and “×” (V-0 and V-1 nonconforming).

  As is apparent from Table 4, in Examples 1 to 12 compared with Comparative Examples 1 to 3, the weight increase rate after the moisture resistance test (high temperature and high humidity test) is less than 5%. It was confirmed that high thermal conductivity can be maintained and the strength of dielectric breakdown is difficult to decrease. In addition, in Comparative Examples 1 to 3, coloring was seen because only the metal container was dispersed, but in Examples 1 to 12, a non-metallic container was used in the first half and a metal container was used in the second half. As a result, almost no coloring was observed. In particular, in Examples 9 and 10, since a predetermined amount of the predetermined flame retardant was contained, it was confirmed that the flame retardancy was improved while suppressing a decrease in mechanical strength.

  From the above results, according to the heat conductive resin composition for LED lighting substrate according to the present invention, it is possible to obtain a molded product having good long-term reliability (thermal conductivity and insulation) under high temperature and high humidity conditions. Was confirmed.

DESCRIPTION OF SYMBOLS 1 Resin 2 Inorganic filler 3 Thermal conductive resin composition for LED lighting board 4 Nonmetallic container 5 Dispersion 6 Blade 7 Container

Claims (6)

  In the thermally conductive resin composition for an LED lighting substrate containing a resin and an inorganic filler, the inorganic filler contains at least magnesium oxide, and the content of the inorganic filler is the total amount of the thermally conductive resin composition for the LED lighting substrate. On the other hand, the weight increase rate after leaving the cured product of the heat conductive resin composition for an LED lighting substrate in an atmosphere of a temperature of 85 ° C. and a relative humidity of 85% for 500 hours is 50 volume% or more and less than 95 volume%. The heat conductive resin composition for LED lighting boards characterized by being less than 5%.   The thermally conductive resin composition for an LED lighting substrate according to claim 1, wherein the resin contains at least one of an epoxy acrylate resin and an unsaturated polyester resin.   The thermally conductive resin composition for LED lighting substrate further contains a flame retardant, the resin contains an epoxy acrylate resin, and the flame retardant contains at least one of a bromine-containing epoxy compound and a bromine-containing acrylic compound. The heat conductive resin composition for LED lighting substrates according to claim 1.   The flame retardant further contains antimony trioxide, and the content of elemental bromine in the thermally conductive resin composition for an LED lighting substrate is 1.0 atm. The thermal conductive resin composition for an LED lighting substrate according to claim 3, wherein the molar ratio of bromine element to antimony element is 3: 1 to 3: 5.   The resin and the inorganic filler are put in a non-metallic container having no stirring blade so that the content of the inorganic filler is 50% by volume or more and less than 95% by volume, and the non-metallic container is rotated and revolved. A first step of obtaining a dispersion in which the resin and the inorganic filler are dispersed, and the dispersion and the inorganic filler are rotated by putting the dispersion in a container having a stirring blade. The manufacturing method of the heat conductive resin composition for LED illumination boards which passes through the 2nd process of disperse | distributing a filler again in this order.   An LED lighting board, comprising: an LED light emitting portion provided on a board obtained by curing the thermally conductive resin composition for an LED lighting board according to any one of claims 1 to 4. .

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