JP6082890B2 - Heat dissipating coating composition, heat dissipating coating film and article to be coated - Google Patents

Description

  The present invention relates to a heat dissipating coating composition capable of forming a coating film excellent in heat dissipation at a site that generates heat in various electric / electronic devices, a heat dissipating coating film comprising the composition, and an article to be coated having the coating film About.

  Conventionally, heat countermeasures have been very important for electrical and electronic devices. For example, power consumption per electronic device component has increased remarkably with higher performance of home appliances, downsizing and high-density mounting of portable devices, and higher speed of microprocessors. As a result, the deterioration of the device and the performance of the product is likely to occur.

  Furthermore, in recent years, the market for LED bulbs and solar cells has been expanding from the viewpoint of energy saving and alternative natural energy. However, these devices have been concentrated in energy in order to achieve high brightness or high concentration. It becomes extremely hot. Therefore, in such electrical / electronic devices, heat radiation countermeasures are usually taken at the component module and finished product level.

Here, heat dissipation measures refer to heat conduction, convection, and heat radiation means for transporting and releasing heat energy from the heat source (high temperature region) inside the electric / electronic device to the low temperature region of the outside world. Designing an optimal means combining the above. Conventionally, heat radiation countermeasures relying on convection with simple and high heat radiation efficiency are common. For example, in various modules used in semiconductor devices, heat radiation fins are installed on the upper surface of a semiconductor element (LSI, power IC, etc.) Attempts have been made to release the heat generated from the semiconductor element to the external environment by the convection action of the radiation fins (see Patent Documents 1 and 2).

  In the case of LED bulbs, the heat energy generated from the light-emitting diode, which is the heat source, is conducted to a highly heat-conductive heat sink made of aluminum or copper, and natural convection or a cooling fan is used from the surface. In general, a means for discharging to the outside by forced convection is employed (see Patent Document 3).

  In the heat dissipation means based on such a physical structure, it is important to increase the heat dissipation efficiency by increasing the surface area as much as possible so that the atmosphere (air) of the external environment is switched as frequently as possible. It is also important to use a material with extremely high thermal conductivity such as aluminum or copper as the heat sink and transport as much heat as possible from the internal heat source to the outermost surface (heat dissipating surface) of the physical heat dissipating means as soon as possible. It is.

  However, when the module or set device is downsized, it becomes difficult to secure a space for installing a heat radiation fin, a cooling fan, etc., and from the viewpoint of weight reduction, design, economy, portability, etc. The use of heavy metals such as copper is also limited. Furthermore, in general electric / electronic devices, the temperature at which heat dissipation measures are required is at most lower than about 200 ° C. and is relatively low temperature, so that the heat dissipation effect by convection has a limit. For this reason, there is an increasing need for an optimal heat dissipation design that combines convection, heat conduction, and radiation. As an effective measure, the number of cases in which a heat-dissipating coating composition is applied to the case of a set device or the surface of a component has increased. ing.

  The heat-dissipating coating composition generally refers to a resin blended with a heat-dissipating filler (inorganic particles) in a binder resin that is responsible for adhesion to various substrates. To increase the heat-dissipating effect of the coating film, Since it is necessary to increase the efficiency of transport of thermal energy to the substrate and the coating film surface, various ceramic particles having excellent thermal conductivity are considered suitable as the heat dissipating filler. In this respect, for example, aluminum nitride (having a thermal conductivity of 100 W / mK or more) used in the heat dissipating material of Patent Document 1 is alumina (aluminum oxide) or silica as pointed out in Patent Document 4. Compared to the above, the thermal conductivity is higher by one digit or more than two digits, so it is considered that it contributes to the heat dissipation of the coating film even when used as a filler for the heat dissipation coating film.

Japanese Patent Laid-Open No. 6-209057 JP-A-6-132433 JP 2004-55229 A Japanese Patent Laid-Open No. 2-133450

  By the way, the amount of heat released per unit area and unit time from the coating film surface greatly depends on the thickness of the coating film, so that the smaller the film thickness, the higher the heat energy transport efficiency. In this respect, the thickness of the coating film by the heat radiating paint is at most about several tens of μm, which is almost two orders of magnitude thinner than the thickness of the heat radiating member such as the aluminum heat radiating fin (millimeter order). Therefore, from this point of view, even without using a filler having high thermal conductivity such as aluminum nitride, depending on the binder resin composition to be combined, a coating film having excellent heat dissipation may be obtained.

  In addition, it is necessary to consider not only the thermal conductivity but also the chemical characteristics of the heat dissipating filler. For example, the aluminum nitride described above easily reacts with moisture in the atmosphere as pointed out in Patent Document 4 at the same time. Since there is a concern that the binder resin composition in the paint may deteriorate with time, it can be said that it is not suitable for a heat-dissipating coating film from this viewpoint.

  On the other hand, it is necessary to select a binder resin composition that can not only improve the heat dissipation of the coating film but also ensure adhesion with the substrate and mechanical strength.

  As described above, the present invention is a novel paint capable of forming a coating film excellent in heat dissipation, adhesion and mechanical strength on the surface of various substrates without using a filler having high thermal conductivity such as aluminum nitride. The main problem is to provide a composition.

  As a result of intensive studies, the present inventor can obtain a coating composition that can solve the above problems by adopting a composition in which a predetermined resin is combined as a binder resin containing a heat radiation filler with relatively low thermal conductivity. I found out.

  That is, the present invention relates to an acrylic resin (a-1), an epoxy resin (a-2), and an amino resin (a) obtained by reacting (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms of alkyl group and styrene. a-3) binder resin composition (A) 10 to 70% by volume, heat-radiating filler (B) 90 to 30% by volume with a thermal conductivity of less than 100 W / mK, and a color pigment (C ) 0-20% by volume of an organic solvent (D) is blended into a liquid or paste heat dissipating paint composition; a heat dissipating coating film comprising the heat dissipating paint composition; The article to be coated.

  According to the heat dissipating coating composition of the present invention, it is possible to form a coating film not only with excellent heat dissipating efficiency but also with excellent mechanical strength and adhesion on the surface of various articles. In addition, since the coating composition has good heat dissipation efficiency of the coating film, it can be built into equipment / parts used in a space where air flow is restricted, such as a sealed housing, and the structure of a heat sink or heat sink. In addition to being particularly suitable for such a small module component, it can be used for products that require heat dissipation measures such as solar cells, organic EL lighting devices, and driving devices.

It is a schematic diagram of the heat dissipation evaluation apparatus of a coating film.

  The heat-dissipating coating composition of the present invention is an acrylic resin (a-1) (hereinafter referred to as component (a-1) obtained from (meth) acrylic acid alkyl esters having 1 to 18 carbon atoms and styrenes. Binder resin (A) (hereinafter referred to as (a-3) component) and epoxy resin (a-2) (hereinafter referred to as (a-2) component) and amino resin (a-3) (hereinafter referred to as (a-3) component). (Referred to as component (A)), heat dissipating filler (B) (hereinafter referred to as component (B)) having a thermal conductivity of less than 100 W / mK, and, if necessary, colored pigment (C) (hereinafter referred to as component (C)) ) In an organic solvent (D) (hereinafter referred to as “component (D)”). That is, the heat-dissipating coating composition is different from a composition that does not contain or substantially does not contain an organic solvent, such as powder coating (JIS-K5000: 2000).

  The component (a-1) constituting the component (A) is an acrylic resin obtained from (meth) acrylic acid alkyl esters having 1 to 18 carbon atoms and styrenes. Can be used without limitation. Examples of the (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, N-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate. , Tert-butyl (meth) acrylate, N-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, ( Such as octadecyl (meth) acrylate, octadecenyl (meth) acrylate, icosyl (meth) acrylate, docosyl (meth) acrylate (cyclopentyl) methacrylate, cyclohexyl (meth) acrylate, etc. From the viewpoint of strength, the alkyl group preferably has about 1 to 12 carbon atoms, more Preferably from one 1 to 5. Examples of the styrenes include styrene, α-methylstyrene, t-butylstyrene, dimethylstyrene, acetoxystyrene, hydroxystyrene, vinyltoluene, chlorovinyltoluene, etc. Styrene is preferred because it contributes to adhesion and strength. In addition, as a monomer which comprises (a-1) component, various well-known alpha olefins, nitriles, (meth) acrylamides, (meth) acrylic-acid hydroxyalkyl esters other than that as needed. Etc. can be used together.

  The amount of alkyl (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group, styrenes and other monomers is not particularly limited, but usually when all the monomers are 100 mol% , About 40 to 60 mol%, about 60 to 40 mol%, and about 0 to 10 mol% in order, preferably 45 to 55 mol%, 54.9 to 45 mol%, and 0.1 to 5 mol% It is.

  (A-1) The manufacturing method of a component is not specifically limited, Various well-known polymerization reactions are employable. For example, the (meth) acrylic acid alkyl esters, styrenes and other monomers are used in the above amounts in the presence of various known radical polymerization initiators, usually at about 20 to 120 ° C. for about 2 to 10 hours. What is necessary is just to make it react. In the reaction, any suitable organic solvent described later can be used as the reaction solvent. Examples of the radical polymerization initiator include potassium persulfate, ammonium persulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobisisobutylnitrile, and 2,2′-azobis. (2,4-dimethylvaleronitrile) and the like. In addition, (a-1) component may use a commercial item, for example, the Almatex 785-5 (brand name) by Mitsubishi Rayon etc. are mentioned.

  As the component (a-2), various known resins can be used without particular limitation as long as they are epoxy resins that can be used in the heat-dissipating coating composition. Specifically, for example, a bisphenol type epoxy resin obtained by glycidylating various bisphenols, a hydrogenated product of the bisphenol type epoxy resin, a phenol novolac resin, a novolac type epoxy resin obtained by reacting a cresol novolac resin with a haloepoxide. And biphenyl type epoxy resin. Examples of the bisphenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, and tetrachlorobisphenol. Examples thereof include A and tetrafluorobisphenol A. Among these, bisphenol type epoxy resins are preferable, and bisphenol A type epoxy resins are particularly preferable from the viewpoint of the strength and adhesion of the coating film. In addition, (a-2) component may use a commercial item, for example, jER828 (brand name) by Mitsui Chemicals, Inc., etc. are mentioned.

  As the component (a-3) constituting the component (A), various known resins can be used without particular limitation as long as they are amino resins that can be used in the heat-dissipating coating composition. Specifically, for example, known moieties obtained by reaction of amino components such as melamine (resin), urea (resin), benzoguanamine (resin), acetoguanamine (resin), spiroguanamine (resin), dicyandiamide and aldehyde Or a completely methylolated amino resin is mentioned. Among these, melamine (resin), preferably alkylated melamine (resin), more preferably a melamine substituted with an alkyl group having 1 to 5 carbon atoms in view of the strength and adhesion of the coating film among these ( Resin). In addition, (a-3) component may use a commercial item, for example, Mitsui Chemicals Co., Ltd. Euban 20SE60 (brand name) etc. are mentioned.

  The component (A) can be obtained by mixing the component (a-1), the component (a-2) and the component (a-3) by various known methods. Further, the weight ratio of each component is not particularly limited. Usually, when the component (a-1) is 100% by weight (in terms of solid content), both the component (a-2) and the component (a-3) Is about 1 to 40% by weight, preferably about 2 to 30% by weight.

  The thermal conductivity of the component (A) is not particularly limited, but is usually 1 W / mK or less, specifically about 0.1 to 0.5 W / mK.

  As the component (B), various known materials can be used without particular limitation as long as the heat conductivity is less than 100 W / mK. Specifically, for example, silicon oxide particles, calcium fluoride particles, boron nitride particles, quartz particles, kaolin particles, aluminum hydroxide particles, bentonite particles, talc particles, salicite particles, forsterite particles, mica particles, cordierite. Examples thereof include fine particles and boron nitride fine particles. In the present invention, since the component (A) is selected as the binder resin, a coating film excellent in heat dissipation can be obtained even when the component (B), which is inferior in thermal conductivity to aluminum nitride, silicon carbide, or the like, is used. become. From this point, the thermal conductivity of the component (B) is 80 W / mK or less, specifically about 0.1 to 65 W / mK, more specifically about 0.1 to 40 W / mK, and more specifically. It may be about 0.1 to 15 W / mK, more specifically about 0.1 to 10 W / mK.

  The component (B) is preferably at least one selected from the group consisting of the aforementioned mica fine particles, forsterite fine particles, silicon oxide fine particles, metal fluoride fine crystal particles, and boron nitride fine particles, particularly from the viewpoint of heat dissipation of the coating film. .

  Further, the mica fine particles and / or forsterite fine particles are used when the temperature reached by the exothermic article to which the coating composition of the present invention is applied is relatively low (specifically, 40 ° C. or more and less than 70 ° C.). Can be preferably employed. Examples of such exothermic articles include general lighting equipment, general household electrical appliances, and MEMS (Micro Electro Mechanical System). When silicon oxide fine particles and forsterite fine particles are used in combination, the volume% ratio is preferably about 9.5: 0.5 to 2: 8 in order.

  In addition, the silicon oxide fine particles and / or the metal fluoride fine particles are a temperature range in which the ultimate temperature of the exothermic article to which the coating composition of the present invention is applied is relatively medium (specifically, 70 ° C. or more and less than 100 ° C. ) Can be preferably employed. Examples of such exothermic articles include lighting fixtures using LEDs, displays, concentrating solar cells, and the like. The silicon oxide fine particles are prepared by mixing sodium silicate and sulfuric acid using high-purity silica sand as a raw material to form a silicate sol, polymerizing these silicate sols to form aggregates, and the like. (See JP-A-9-71723, etc.) and are porous or non-porous particles. Examples of commercially available products include Cicilia 730, Cicilia 740, Cicilia 770, Cicilia 530, Cicilia 540, Cicilia 550 (all are trademarks) manufactured by Fuji Silysia Co., Ltd., and the like. Examples of the metal fluoride fine particles include lithium fluoride, calcium fluoride, barium fluoride, and magnesium fluoride. When silicon oxide fine particles and metal fluoride crystal fine particles are used in combination, the volume% ratio is preferably about 9.5: 0.5 to 2: 8 in order.

  In addition, when the silicon oxide fine particles and / or boron nitride fine particles reach a temperature range (specifically, 100 ° C. or more and less than 200 ° C.) where the exothermic article to which the coating composition of the present invention is applied reaches a relatively high temperature. Can be preferably employed. Examples of such exothermic articles include module parts in which a power semiconductor and its peripheral parts are combined. When silicon oxide fine particles and boron nitride fine particles are used in combination, the volume% ratio is preferably about 9.5: 0.5 to 2: 8 in order.

  The shape of the component (B) is not particularly limited, but the average primary particle size is usually in consideration of the mechanical strength and design properties (smoothness) of the coating film and the heat dissipation efficiency based on the appropriate unevenness of the coating film. It is about 0.1-50 micrometers, More preferably, it is 1-50 micrometers. The median diameter D50 is not particularly limited, but is usually 50 μm or less, preferably 40 μm or less.

  As the component (C), various known compounds can be used without particular limitation, and examples thereof include titanium oxide, carbon black, and iron oxide. In addition, although the thermal conductivity of (C) component is not specifically limited, Usually, it is about 1-30 W / mK.

  Moreover, although the usual of (C) component is not specifically limited, In consideration of the mechanical strength and design property (smoothness) of a coating film, and the heat dissipation efficiency based on the moderate unevenness | corrugation of a coating film, normally an average primary particle The diameter is 0.01 to 10% of the average primary particle diameter of the component (B). Further, the median diameter D50 is not particularly limited, but it is usually preferably 1 μm or less.

  The coating composition of the present invention can be used as a clear coating (JIS-K5000: 2000) in which the component (A) and the component (B) are blended with the component (D). And if necessary, it can also be used as a colored paint formed by using the component (C) in combination.

  Although the usage-amount of (A) component-(C) component in the coating composition of this invention is not specifically limited, when the heat dissipation of a coating film, hardness, adhesiveness with a base material, etc. are considered, (A) component- ( C) When the component is 100% by volume, about 10 to 70% by volume, about 90 to 30% by volume, and about 0 to 20% by volume, preferably about 10 to 50% by volume, about 90 to 50% by volume and It is about 0-15 volume%, More preferably, it is 10-40 volume%, 80-50 volume%, and 5-15 volume%.

  Examples of the component (D) include aromatic hydrocarbons such as xylene, ethylbenzene, toluene, and trimethylbenzene; aliphatic hydrocarbons such as isoparaffin, monoalcohols such as methanol, ethanol, propanol, isopropanol, butyl alcohol, and isobutyl alcohol; ethylene Examples thereof include polyhydric alcohols such as glycol; acetate solvents such as methyl acetate, ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ketones such as methyl ethyl ketone and cyclohexanone; Among these, workability at the time of curing and coating, film formability when used as a coating film, and those that do not impair the desired hardness when used as a cured product, especially those having a boiling point of about 100 to 200 ° C Is preferred. Moreover, it is preferable to use what contains an aromatic hydrocarbon as an organic solvent. Moreover, the usage-amount of (D) component is the range from which the non volatile matter of the coating composition of this invention will be about 40 to 70 weight%.

  The coating composition of the present invention suitably includes thickeners such as organic bentonite, carboxymethylcellulose, and polyvinyl alcohol, various dispersants such as polyacrylic acid and polyacrylate, other matting agents, antifoaming agents, You may mix | blend additives, such as a leveling agent, a dripping prevention agent, a surface regulator, a viscosity regulator, a ultraviolet absorber, and a wax.

  The heat dissipating coating film of the present invention is obtained by applying the heat dissipating coating composition of the present invention to various substrates and baking it at 120 to 200 ° C. The coating means is not particularly limited, but from the viewpoints of productivity, economic efficiency, coating properties on minute substrates, and design pattern formation, in particular, spray, dip, bar coating, screen stencil, pad stamp printing Ink jet printing, a dispenser and the like are preferable. Further, a groove pattern or a dot pattern may be formed on the surface of the coating film in order to enhance the heat dissipation effect on the outermost surface of the coating film or to give design properties.

  Moreover, the volume% of (A) component in the said coating film, (B) component, and (C) component used as needed becomes equal to that prescribed | regulated about the heat-radiating coating composition of this invention. This is because, when the heat-radiating coating composition of the present invention is applied to an exothermic article to form a cured coating film, the organic solvent is almost evaporated.

  The article to be coated of the present invention has a heat-dissipating coating film, and the article to which the heat-dissipating coating composition of the present invention is applied includes various metals (iron, aluminum, copper and alloys thereof) and heat resistance. Sexual materials and others.

  Hereinafter, the present invention will be described in detail through examples, but the scope of the present invention is not limited thereby.

Preparation Example 1
(A-1) Commercially available acrylic resin (methyl methacrylate / n-butyl acrylate / styrene terpolymer (manufactured by Mitsui Chemicals)) as component, (a-2) commercially available bisphenol A as component Type resin (manufactured by Mitsui Chemicals) and commercially available butylated melamine resin (manufactured by Mitsui Chemicals) as component (a-3) are mixed so that the weight ratio is 7.4: 1: 1 Then, by diluting with xylene, a binder resin solution having a nonvolatile content of 47% by weight was obtained. Next, the binder resin solution and porous silica powder (trade name “Cycilia 470”, manufactured by Fuji Silysia Chemical Ltd., average primary particle size 14.1 μm, thermal conductivity 1.0 W / mK) as component (B) Are mixed in a container so that the volume% ratio is 44.6% and 55.4% in order, and the agglomerates that can be visually confirmed are stirred and mixed, and then xylene is added to prepare a low-viscosity slurry. Subsequently, the mixture was uniformly mixed using a homogenizer to obtain a heat-dissipating coating composition having a nonvolatile content of 47% by weight.

Preparation Examples 2-9, Comparative Preparation Examples 1-4
(A) Volume% ratio of component, type of (B) component and volume% ratio, and preparation example other than changing type and volume% ratio of heat radiation filler other than (B) component as shown in Table 1 In the same manner as in No. 1, a heat-dissipating coating composition (both having a nonvolatile content of 47% by weight) was obtained. In Comparative Preparation Example 4, the binder resin solution was used as it was.

Mica: Commercially available mica fine particles (trade name “PDM-8DF”, manufactured by Topy Industries, Ltd., average primary particle size 12.0 μm)
Forsterite: Commercially available forsterite fine particles (trade name “FF-200 · M40”, manufactured by Marusu Shakusha Limited, average primary particle size 2.5 μm)
SiO ₂ ... Commercially available porous silica fine particles (trade name “Cycilia 470”, manufactured by Fuji Silysia Chemical Ltd., average primary particle size 14.1 μm)
CaF ₂ ... Commercially available calcium fluoride powder (trade name “FLUORITE POWDER CALCIUM FLUORIDE”, China Tuhsu Flavors & Fragrances Import & Export Co. Ltd, average primary particle size 38.0 μm)
BN: Commercially available boron nitride fine particles (trade name “BORONID S3”, manufactured by ESK Ceramics, average primary particle size 10.0 μm)
TiO ₂ .. Commercially available titania powder (trade name “TI TONE R-32”, manufactured by Sakai Chemical Industry Co., Ltd .; average primary particle size 0.1 μm, thermal conductivity 25 W / mK)
AlN: Commercially available high-purity aluminum nitride powder (trade name “H grade”, manufactured by Tokuyama Corporation, average primary particle diameter average particle diameter 1.1 μm)
SiC: Commercially available silicon carbide powder (trade name “Shinano Random GP-3000”, manufactured by Shinano Denki Smelting Co., Ltd .; average primary particle size 2.0 μm)
Medium: It means that the design is intended for use in an intermediate temperature range of 70 ° C. or more and less than 100 ° C.
Low means that the design is intended for use in a low temperature range of 40 ° C. or more and less than 70 ° C.
High: means that the design is intended for use in a high temperature range of 100 ° C. or more and less than 200 ° C.

<Formation of heat-dissipating coating intended for use in the middle temperature range, performance evaluation>
Using the applicator (50-100 μm gap) on the aluminum plate (2 mm thickness × 50 mm width × 100 mm length: JIS H4000 specification, product name A1050P), the target film thickness is 40-50 μm. It applied so that it might become. Next, after leaving it indoors for about 5 minutes, it was baked in a dryer at 160 ° C. for 30 minutes. Similarly, the heat-dissipating coating compositions of Preparation Examples 2 to 5 and Comparative Preparation Examples 1 and 2 were subjected to baking treatment plates.

  For the heat-dissipating coating compositions of Preparation Examples 6 to 9, using other applicators (75 to 100 μm gap), the same baking treatment plate was applied except that the target film thickness was 70 to 90 μm. Got. The heat dissipation coating composition of Comparative Preparation Example 3 was similarly treated to obtain a baking-treated plate.

  About the coating composition which does not contain an inorganic particle based on the comparative preparation example 4, it applied similarly to the said aluminum plate so that a target film thickness might be set to 30-50 micrometers using another applicator (150-200 micrometers gap). Thus, a baking-treated plate was obtained.

  Moreover, the said aluminum plate itself was used for the blank test (reference example).

<Evaluation of heat dissipation performance of coating film>
Example 1
As shown in FIG. 1, a heat source (shunt resistor, manufactured by PCN, model number PBH1ΩD) in which the baking treatment plate according to Preparation Example 1 is installed in the measurement box in the upper end opening of the measurement box formed of a heat insulating material. , Rated power 10 W, size about 2 cm long × about 1.5 cm width × about 0.2 cm thick). Next, a thermocouple is brought into contact with the heat-dissipating coating film surface and the heat source lower surface of the baking treatment plate so as to be in the same position in the vertical direction, and then a constant current (2.75 A) is applied to measure the upper surface measurement point (temperature The time change of the temperature at T1) and the measurement point on the lower surface (temperature T2) was recorded with a data logger thermometer. Table 2 shows the values of T1 and T2 in the steady state.

Examples 2 to 9, Comparative Examples 1 to 4, Reference Example 1
T1 and T2 were measured in the same manner for the baking treatment plates and blank plates according to Preparation Examples 2 to 9, Comparative Preparation Examples 1 to 3 and Comparative Preparation Example 6.

  The baking treatment plate according to Example 1, the baking treatment plate according to Comparative Preparation Example 2 and the blank plate used in Reference Example 1 were further the same as in Example 1 except that the applied current was 2.00 A. T1 and T2 were measured.

[Evaluation of heat dissipation effect of coating film]
The difference (Δ1 ° C.) between the actually measured temperature of the heat dissipating coating surface of the baking treatment plate according to Example 1 and the surface measurement temperature of the heat dissipating coating plate (only the binder resin) of the baking treatment plate of Comparative Example 6, and Table 2 shows the difference (Δ2 ° C.) between the actually measured temperature of the heat dissipating coating film surface of the baking treatment plate according to Example 1 and the actually measured surface temperature of the blank plate of Reference Example 1. It means that the smaller the measured temperature, that is, the larger the numerical values of the temperature differences Δ1 and Δ2, the higher the heat dissipation effect of the coating film. Table 2 also shows the actually measured heat radiation coating temperatures, Δ1 and Δ2 for the baking treatment plates according to Examples 2 to 9, Comparative Examples 1 to 3 and Comparative Example 6.

[Temperature suppression effect of heat source (shunt resistance) due to heat dissipation action of coating film]
The measured temperature difference (Δ3 ° C.) between the lower surface temperature of the shunt resistor (heat source) brought into contact with the baking treatment plate according to Example 1 and the lower surface temperature of the shunt resistance made into contact with the baking treatment plate of Comparative Example 4, and Table 2 shows the measured temperature difference (Δ4 ° C.) between the lower surface temperature of the shunt resistor (heat source) brought into contact with the baking treatment plate according to Example 1 and the lower surface temperature of the shunt resistor brought into contact with the blank plate of Reference Example 1. Show. It means that the smaller the measured temperature, that is, the larger the numerical values of the temperature differences Δ3 and Δ4, the more the temperature increase of the shunt resistor itself is suppressed by the heat dissipation action of the coating film. Table 2 also shows the actually measured heat-dissipating coating temperature, Δ3 and Δ4 for the baking treatment plates according to Examples 2 to 9, Comparative Examples 1 to 3 and Comparative Example 6.

<Evaluation of adhesion strength: cross cut test>
About the baking processing board which concerns on Example 1, the adhesive force of the coating film was evaluated based on the cross-cut test defined by JISD0202. Specifically, 100 grids were prepared on the surface of the coating film with a cutter knife, and a commercially available adhesive tape was pressure-bonded and left for 1 to 2 minutes, and the remaining degree of the coating film when peeled in the vertical direction was determined. Visual evaluation was performed according to the following criteria. It evaluated similarly about the baking process board which concerns on Examples 2-9 and Comparative Examples 1-3. The results are shown in Table 2.

1: Good adhesion (residual rate 95% to 100%)
2: Slightly good adhesion (residual rate 65% or more and less than 95%)
3: Poor adhesion (residual rate less than 65% to total peeling)

<Evaluation of adhesion strength: scratch test>
About the baking processing board which concerns on Example 1, the mechanical strength of the coating film was evaluated by the scratch test. Specifically, a diamond indenter (tip diameter R 0.2 mm) was brought into contact with the coating surface, and the processing plate was moved 40 mm in the horizontal direction while increasing the load from 0 N to 20 N (speed: 1.4 mm / s). . And the position which the coating film peeled was detected with the microscope and the acoustic emission sensor, and the adhesiveness was evaluated on the following references | standards. The results are shown in Table 2.

1: Good adhesion (the load of the diamond indenter at the coating film peeling position is 20 N or more)
2: Adhesion failure (diamond indenter load at coating film peeling position is less than 20N)

  From Table 2, the coating films (Examples 1 to 9) using the heat dissipating coating composition of the present invention are well known as highly thermally conductive fillers even when the heat source temperature is high (applied current 2.75 A). Coating film using aluminum nitride fine particles (Comparative Example 1), coating film using silicon carbide fine particles (Comparative Example 2), coating film in which component (B) is excessively used (Comparative Example 3), and (B ) It can be seen that an improvement in heat dissipation performance of about 15 to 65% can be obtained as compared with the coating film not using the component (Comparative Example 6). In particular, from the results of Comparative Examples 1 and 2, the present invention employs a predetermined binder resin composition, so that heat dissipation and adhesion can be achieved without using high thermal conductive fillers such as aluminum nitride fine particles and silicon carbide fine particles. It was also found that a coating film having excellent mechanical properties can be obtained.

  Further, even when the heat source temperature is low (applied current of 2.00 A), the coating film (Example 1) using the heat dissipating coating composition of the present invention contains a coating composition containing inorganic particles other than the component (B). Compared with the coating film using the film (Comparative Example 2), the heat radiation performance is improved by at least about 35%.

  Further, regarding the blank plate of Reference Example 1, the measured surface temperature at the applied current of 2.75 A (105.2 ° C.) and that of the blank plate of Reference Example 2 at the applied current of 2.00 A (72.5 ° C.) In view of the above, it becomes clearer that the coating composition of the present invention gives a coating film excellent in heat dissipation.

  In addition, since the temperature range of 72.5-105.2 degreeC corresponds to the temperature at the time of use of lighting fixtures, such as an LED bulb, for example, when the coating composition of this invention is applied to the housing outer surface of an LED bulb By the heat dissipation effect, it is possible to expect a life improvement of 10000 to 30000 hr and a brightness improvement effect of 10% or more (Sharp Technical Report, 99 (2009. 9), 17p-19p, and Matsushita Electric Engineering Technical Report, 99 (2008). .9), 22p-26p).

<Preparation of heat dissipation coating intended for use in low temperature range>
Example 10
Using the applicator (50-100 μm gap) on the aluminum plate (2 mm thickness × 50 mm width × 100 mm length: JIS H4000 specification, product name A1050P), the heat dissipating coating composition of Preparation Example 10 has a film thickness of 40-50 μm. It was applied as follows. Next, after leaving it indoors for about 5 minutes, it was baked in a dryer at 160 ° C. for 30 minutes. Similarly to Preparation Examples 11 and 12, a baking-treated plate was obtained.

Comparative Example 5
About the heat-radiating coating composition of Comparative Preparation Example 2 (containing silicon carbide fine particles), a baking treatment plate was obtained in the same manner as in Example 10.

Comparative Example 6
About the heat-radiating coating composition of Comparative Preparation Example 5 (containing a relatively large amount of mica fine particles), a baking treatment plate was obtained in the same manner as in Example 10.

Comparative Example 7
About the heat-radiating coating composition (not containing inorganic fine particles) according to Comparative Preparation Example 4, a baking treatment plate was obtained in the same manner as in Example 10.

  The aluminum plate itself was subjected to a blank test (Reference Example 2).

<Evaluation of heat dissipation performance of coating film>
Example 10
In accordance with the performance evaluation items of the heat-dissipating coating film intended to be used in the middle temperature range, thermocouples are provided on the heat-dissipating coating surface and the heat source lower surface of the treatment plate according to Example 10 in the vertical direction. After making contact so as to be in position, a constant current (1.90 A) is applied, and the time change of the temperature at the upper measurement point (temperature T1) and the lower measurement point (temperature T2) is recorded by a data logger thermometer. did. The results are shown in Table 3.

Examples 11-12, Comparative Examples 5-7, Reference Example 2
The test plates according to Examples 11 to 12 and Comparative Examples 5 to 7 and the blank plate according to Reference Example 2 were similarly measured for T1 and T2 when the applied current was 1.90A. The results are shown in Table 3.

  In addition, about the baking process board which concerns on Example 10, the baking process plate which concerns on the comparative example 5, and the blank board which concerns on the reference example 2, it is T1 similarly to Example 10 except having applied electric current to 1.50A. And T2. The results are shown in Table 3.

[Evaluation of heat dissipation effect of coating film]
According to the evaluation method of the heat radiation coating film for the medium temperature range, Δ1 and Δ2 were also evaluated for the heat radiation coating film for the high temperature region, and the values are shown in Table 3.

[Temperature suppression effect of heat source (shunt resistance) due to heat dissipation action of coating film]
According to the evaluation method of the heat radiation coating film for the medium temperature range, Δ3 and Δ4 were also evaluated for the heat radiation coating film for the high temperature region, and the values are shown in Table 3.

<Evaluation of adhesion: cross-cut test and scratch test>
A cross-cut test and a scratch test were performed according to the evaluation method of the heat radiation coating film for the middle temperature range, and the results are shown in Table 3.

  From Table 3, the coating films (Examples 10 to 12) using the heat-dissipating coating composition for the low temperature range are other than the component (B) even when the heat source temperature is high (applied current 1.90 A). Compared to a coating film using a coating composition containing inorganic particles (Comparative Example 5) and a coating film not containing inorganic particles (Comparative Example 7), at least about 16% or more is improved in heat dissipation performance. I understand.

  Even when the heat source temperature is low (applied current 1.50 A), the coating film (Example 10) using the heat dissipating coating composition of the present invention contains a coating composition containing inorganic particles other than the component (B). It can be seen that at least about 18% or more is improved in heat dissipation performance as compared with the coating film using (Comparative Example 5).

  In addition, the blank surface measurement temperature (66.2 ° C.) when the applied current is 1.90 A according to Reference Example 2 and that (47.4 ° C.) when the applied current is 1.50 A are taken into account. Then, it turns out that the coating composition of this invention has given the coating film excellent in heat dissipation even when the temperature of a to-be-coated article is a low temperature range of 47.4 degreeC-66.2 degreeC. .

<Preparation of heat-dissipating coating film intended for use in high temperature range>
Example 13
Using the applicator (50-100 μm gap) on the aluminum plate (2 mm thickness × 50 mm width × 100 mm length: JIS H4000 specification, product name A1050P), the heat dissipating coating composition of Preparation Example 10 has a film thickness of 40-50 μm. It was applied as follows. Next, after leaving it indoors for about 5 minutes, it was baked in a dryer at 160 ° C. for 30 minutes. In the same manner as in Preparation Examples 14 and 15, a baking-treated plate was obtained.

Comparative Example 8
About the heat-radiating coating composition of Comparative Preparation Example 2 (containing silicon carbide fine particles), a baking treatment plate was obtained in the same manner as in Example 13.

Comparative Example 9
About the heat-radiating coating composition of Comparative Preparation Example 5 (containing a relatively large amount of boron nitride fine particles), a baking treatment plate was obtained in the same manner as in Example 13.

Comparative Example 10
About the heat-radiating coating composition (not containing inorganic fine particles) according to Comparative Preparation Example 4, a baking treatment plate was obtained in the same manner as in Example 13.

  The aluminum plate itself was subjected to a blank test (Reference Example 3).

<Evaluation of heat dissipation performance of coating film>
Example 13
In accordance with the performance evaluation items of the heat-dissipating coating film intended to be used in the middle temperature range, thermocouples are provided on the heat-dissipating coating surface and the heat source lower surface of the treatment plate according to Example 13 in the vertical direction. After making contact so as to be in position, a constant current (4.80 A) is applied, and the time change of the temperature at the upper measurement point (temperature T1) and lower measurement point (temperature T2) is recorded with a data logger thermometer did. The results are shown in Table 4.

Examples 14-15
Similarly, for the test plates according to Examples 11 to 12, T1 and T2 were measured when the applied current was 4.80 A. The results are shown in Table 4.

Comparative Example 8
For the test plate according to Comparative Example 8, T1 and T2 were measured when the applied current was 5.20 A. The results are shown in Table 4.

Comparative Example 9
For the test plate of Comparative Example 9, T1 and T2 were measured when the applied current was 4.80 A. The results are shown in Table 4.

Comparative Example 10
For the test plate of Comparative Example 9, T1 and T2 were measured when the applied current was 5.20 A. The results are shown in Table 4.

Reference example 3
For the blank plate according to Reference Example 3, T1 and T2 were measured when the applied current was 5.60 A. The results are shown in Table 4.

  In addition, T1 and T2 when the applied current was set to 3.20 A were further measured for the baking treatment plate according to Example 13 and the baking treatment plate according to Comparative Example 8. For the blank plate according to Reference Example 3, T1 and T2 when the applied current was 3.50 A were further measured, and the results are shown in Table 4.

[Evaluation of heat dissipation effect of coating film]
According to the evaluation method of the heat radiation coating film for the medium temperature range, Δ1 and Δ2 were also evaluated for the heat radiation coating film for the high temperature region, and the values are shown in Table 4.

[Temperature suppression effect of heat source (shunt resistance) due to heat dissipation action of coating film]
According to the evaluation method of the heat radiation coating film for the medium temperature range, Δ3 and Δ4 were also evaluated for the heat radiation coating film for the high temperature region, and the values are shown in Table 4.

<Evaluation of adhesion: cross-cut test and scratch test>
A cross-cut test and a scratch test were performed according to the evaluation method of the heat radiation coating film for the middle temperature range, and the results are shown in Table 4.

  From Table 4, the coating films (Examples 13 to 15) using the heat dissipating coating composition of the present invention are coating compositions containing inorganic particles other than the component (B) even when the heat source temperature is high. It can be seen that the heat dissipation performance is improved by at least about 20% compared to the coating film used (Comparative Example 8) and the coating film not containing inorganic particles (Comparative Example 10).

  Further, even when the heat source temperature is relatively low in the high temperature region, the coating film using the heat dissipating coating composition of the present invention (Example 13) is a coating composition containing inorganic particles other than the component (B). Compared with the coating film used (Comparative Example 8), it can be seen that the heat dissipation performance is improved by at least about 30% or more.

Further, according to Reference Example 3, the surface temperature of the blank plate measured when the applied current is 5.60 A (203.7 ° C.) and that of the blank plate when the applied current is 3.50 A (121.4 ° C.). , The coating composition of the present invention gives a coating film having excellent heat dissipation even at least when the temperature of the article to be coated is a high temperature range of 121.4 ° C. to 203.7 ° C. I understand that.

Claims (10)

From an acrylic resin (a-1), an epoxy resin (a-2) and an amino resin (a-3) obtained by reacting a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms of an alkyl group and styrenes The binder resin composition (A) 10 to 70% by volume, the heat dissipating filler (B) 90 to 30% by volume less than 100 W / mK, and the color pigment (C) 0 to 20% by volume as necessary. % Or an organic solvent (D), and a liquid or paste heat-dissipating coating composition. The heat-radiating coating composition according to claim 1, wherein the component (B) is at least one selected from the group consisting of mica fine particles, forsterite fine particles, silicon oxide fine particles, metal fluoride fine crystal particles, and boron nitride fine particles. The heat dissipating coating composition according to claim 1 or 2, wherein the component (a-2) is a bisphenol type epoxy resin. (A-3) A component is a melamine resin, The heat-radiating coating composition in any one of Claims 1-3. (B) The heat-radiating coating composition in any one of Claims 1-4 whose average primary particle diameter of a component is 0.1-50 micrometers. The heat dissipating coating composition according to claim 1, wherein the component (C) is at least one selected from the group consisting of titanium oxide, carbon black, and iron oxide. The heat-radiating coating composition according to any one of claims 1 to 6, wherein the average primary particle diameter of the component (C) is 0.01 to 10% of the average primary particle diameter of the component (B). (D) The heat-radiating coating composition according to any one of claims 1 to 7, wherein the component contains an aromatic hydrocarbon solvent. A heat dissipating coating film comprising the heat dissipating coating composition according to claim 1. An article to be coated having the heat-radiating coating film according to claim 9.