WO2013069468A1

WO2013069468A1 - Heat-radiating coating and structure

Info

Publication number: WO2013069468A1
Application number: PCT/JP2012/077609
Authority: WO
Inventors: 茂木　繁; 和紀石川; 赤塚　泰昌; 長嶋　憲幸
Original assignee: 日本化薬株式会社
Priority date: 2011-11-09
Filing date: 2012-10-25
Publication date: 2013-05-16
Also published as: TW201323537A; JP2013100409A

Abstract

[Problem] Provided are: a heat-radiating resin that exhibits excellent heat resistance while simultaneously exhibiting excellent heat-radiating properties, without including any fillers, as a type of cooling method such as those used in power devices in such fields as the electric, electronic and automotive fields, and specifically in the fields of high-output inverters, high-output motors, and the like; and a structure obtained by applying a coating of the heat-radiating resin, and then drying and hardening the same. [Solution] A heat-radiating coating characterized by containing: an aromatic polyamide resin (A) containing a phenolic hydroxyl group and having a structure represented by formula (1) (in the formula, m and n satisfy the following relationship, in mean values: 0.005≤n/(m+n)<1. Also, m+n is an integer between 0 and 230, inclusive. Ar₁ represents a divalent aromatic group. Ar₂ represents a divalent aromatic group having a phenolic hydroxyl group. Ar₃ represents a divalent aromatic group.); an epoxy resin (B); a curing catalyst (C); and an organic solvent (D) in the amount of 30-2,000 parts by weight in relation to 100 parts by weight of the sum of the aforementioned components (A, B, C).

Description

Thermal radiation paint and structure

The present invention relates to a paint excellent in heat dissipation and a structure to which the paint is applied. More specifically, it is excellent in thermal radiation with the effect of suppressing the temperature rise of the object by forming a coating film by applying it to an object that easily accumulates heat and making it easy to release the heat accumulated by the coating film. The present invention relates to an electrically insulating paint and a structure obtained by applying the electrically insulating paint to a metal heat conductor.

In recent years, in electric and electric devices such as motors and semiconductor modules, heat generation during operation has become a major problem as the devices are powered up. If this heat cannot be removed properly and the temperature of the device rises, the capability of the device will decrease and the life of the device may even be shortened.
Far-infrared radiation coating materials have been known for a long time, and are used, for example, to increase the thermal efficiency of heating elements such as far-infrared heaters. Most of these paints are obtained by dispersing an inorganic oxide filler such as aluminum oxide, titanium, silicon, zirconium, iron, copper, cobalt, nickel, manganese, and chromium in a binder. As the binder, acrylic resin, epoxy resin, silicone resin, phosphate, silicate and the like are used. (Patent Document 1)
When an acrylic resin or an epoxy resin is used as a binder, even if heat resistance is high, it is around 150 ° C., and when used at a high temperature for a long time, there is a problem that the coating film deteriorates and peels off. Further, when the inorganic filler is dispersed, if the specific gravity of the filler is high, the filler is settled, and there is a problem that the coating film surface becomes non-uniform.

JP 2009-136848 A

The object of the present invention is to obtain a heat-radiating paint having excellent heat resistance and insulating properties and having a smooth coated finish without using an inorganic filler.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, a paint produced using a resin composition comprising a polymer having a specific structure and an epoxy resin satisfies the above-mentioned purpose. As a result, the present invention has been completed.

That is, the present invention provides (1) the following formula (1)

(In the formula, m and n are average values, 0.005 ≦ n / (m + n) <1, and m + n is a positive number from 0 to 230. Ar ₁ is a divalent aromatic group, Ar ₂ is a divalent aromatic group having a phenolic hydroxyl group, Ar ₃ is a divalent aromatic group), and a phenolic hydroxyl group-containing aromatic polyamide resin (A) or epoxy resin (B) having a structure represented by A thermal radiation paint comprising 30 to 2000 parts by weight of an organic solvent (D) with respect to 100 parts by weight of the total of the curing catalyst (C),
(2) Ar ₁ in the compound of formula (1) is a residue of one or more acids selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and fumaric acid, and Ar ₂ is 5-hydroxyisophthalic acid A residue of one or more acids selected from the group consisting of 4-hydroxyisophthalic acid, 2-hydroxyphthalic acid, 3-hydroxyphthalic acid, and Ar ₃ is 3,3′-diaminodiphenyl ether, 3,4′- The thermal radiation coating composition according to the above (1), which is a residue of one or more amines selected from the group consisting of diaminodiphenyl ether and 4,4′-diaminodiphenyl ether,
(3) The thermal radiation paint according to the above (1) or (2), which does not contain an inorganic filler,
(4) a heat conductor and a structure having a layer obtained by applying the heat-radiating paint according to any one of (1) to (3) above to the outer surface and drying and curing the coating;
(5) The structure according to (4) above, wherein the thickness of the thermal radiation coating layer is 0.5 to 300 μm,
It is about.
In the present specification, “residue of acid” and “residue of amine” indicate a residue structure that is formed by dehydration condensation of a dicarboxylic acid and a diamine and is technical common knowledge in the art.

The heat resistance of the coating film according to the present invention is as high as 250 ° C., excellent in heat dissipation, excellent in insulation, and contains no inorganic filler, so that the coating film properties do not become uneven and the surface is smooth. Also excellent.

Hereinafter, embodiments of the present invention will be described.
In the present invention, the phenolic hydroxyl group-containing aromatic polyamide resin as component (A) is used as a curing agent for the epoxy resin as component (B). The polyamide resin of component (A) can be synthesized according to, for example, the description in JP-A No. 2006-124545. Below, it explains in detail about the manufacturing method of the component (A) used in this invention.

In the production of the aromatic polyamide resin of component (A), the following aromatic diamine (formula (i)) is added to the total number of moles of aromatic dicarboxylic acid (formula (ii) and optionally formula (iii)). Charge to condense and condense.

(In the formula, Ar ₃ represents a divalent aromatic group.)

(In the formula, Ar ₂ represents a divalent aromatic group having a phenolic hydroxyl group.)

(In the formula, Ar ₁ represents a divalent aromatic group.)

Examples of aromatic diamines represented by formula (i) include diaminobenzenes such as diaminobenzene, diaminotoluene, diaminophenol, diaminomethylbenzene, diaminomesitylene, diaminochlorobenzene, diaminonitrobenzene or diaminoazobenzene; diamino such as diaminonaphthalene; Naphthalenes; diaminobiphenyls such as diaminobiphenyl or diaminodimethoxybiphenyl; diaminodiphenyl ethers such as 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, or diaminodiphenyl ethers such as diaminodimethyldiphenyl ether Ale, methylene dianiline, methylene bis (methoxyaniline), methylene bis (dimethoxyaniline) Anilines such as methylene bis (ethylaniline), methylene bis (diethoxyaniline), methylene bis (ethoxyaniline), methylene bis (diethoxyaniline), methylene bis (dibromoaniline), isopropylidenedianiline or hexafluoroisopropylidenedianiline, diaminobenzophenone Diaminobenzophenones such as diaminodimethylbenzophenone, and the like; diaminoanthraquinone, diaminodiphenyl thioether, diaminodiphenyl sulfoxide, diaminofluorene, etc., among others, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4 ′ -Diaminodiphenyl ether is preferred. The amount of the aromatic diamine used is usually 1.001 to 1.5 mol per 1 mol of the aromatic dicarboxylic acid described below.

Examples of aromatic dicarboxylic acids having a phenolic hydroxyl group of formula (ii) include hydroxyisophthalic acid such as 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyphthalic acid, 3-hydroxyphthalic acid, and dihydroxyisophthalic acid. Examples include hydroxyisophthalic acids such as acids; hydroxyterephthalic acids such as hydroxyterephthalic acid and dihydroxyterephthalic acid, and the like. 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyphthalic acid, and 3-hydroxyphthalic acid are preferable. Examples of aromatic dicarboxylic acids having no phenolic hydroxyl group of formula (iii) include phthalic acids such as phthalic acid, isophthalic acid, terephthalic acid, benzenediacetic acid, benzenedipropionic acid, biphenyldicarboxylic acid, oxydibenzoic acid, thiodi Benzoic acids such as benzoic acid, dithiodibenzoic acid, dithiobis (nitrobenzoic acid), carbonyldibenzoic acid, sulfonyldibenzoic acid, naphthalenedicarboxylic acid, methylenedibenzoic acid, isopropylidenedibenzoic acid, hexafluoroisopropylidenebenzoic acid, naphthalene Examples thereof include dicarboxylic acid and pyridinedicarboxylic acid, and phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and fumaric acid are preferable. In the aromatic polyamide resin of the component (A), among these aromatic dicarboxylic acids, the aromatic dicarboxylic acid of the formula (ii) is essential, but it is harder to use the aromatic dicarboxylic acid of the formula (iii) in combination. It is preferable because it is easy to give flexibility to objects. When used in combination, the structures of the aromatic dicarboxylic acids of the formulas (ii) and (iii) are preferably combinations having both isophthalic acid skeletons. In the dicarboxylic acid of the formula (ii) and the aromatic dicarboxylic acid of the formula (iii), the proportion of the hydroxyl group contained in the dicarboxylic acid component is usually 0.5 mol% or more, preferably 1 mol% or more, particularly preferably 5 Both are used within a range of at least mol%. In the following description, the term “aromatic dicarboxylic acid” refers to both aromatic dicarboxylic acids of the formula (ii) and formula (iii).
Moreover, in the said aromatic diamine and aromatic dicarboxylic acid, the combination of a preferable compound is still more preferable.

The condensation reaction between the aromatic dicarboxylic acid and the aromatic diamine is carried out in the presence of an aromatic phosphite as a condensing agent. At this time, it is preferable to use a pyridine derivative as a catalyst.

The aromatic phosphite used here includes triphenyl phosphite, diphenyl phosphite, tri-o-tolyl phosphite, di-o-tolyl phosphite, tri-m-tolyl phosphite. , Di-m-tolyl phosphite, tri-p-tolyl phosphite, di-p-tolyl phosphite, tri-p-chlorophenyl phosphite and the like. The amount of the aromatic phosphite used is generally 0.6 to 1.5 mol, preferably 0.7 to 1.2 mol, per 1 mol of the total of aromatic diamine and aromatic dicarboxylic acid.

Examples of the pyridine derivative include pyridine, 2-picoline, 3-picoline, 4-picoline, 2,4-lutidine, 2,6-lutidine, 3,5-lutidine and the like. The amount of the pyridine derivative to be used is usually 1.0 to 5.0 mol, preferably 2.0 to 4.0 mol, per 1 mol of the total of aromatic diamine and aromatic dicarboxylic acid.

Further, in order to obtain an aromatic polyamide resin having a higher molecular weight, the reaction can be carried out by adding inorganic salts such as lithium chloride. The amount of the inorganic salt used is usually 0.01 to 0.5 mol, preferably 0.05 to 0.3 mol, per 1 mol of the total of the aromatic diamine and aromatic dicarboxylic acid.

The reaction is performed by charging an aromatic dicarboxylic acid, an aromatic diamine, a condensing agent, and if necessary, a pyridine derivative and an inorganic salt in a solvent. The solvent is not particularly limited as long as it is a solvent that solvates with an aromatic polyamide resin. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethyl. Examples thereof include sulfoxide and mixed solvents thereof, and N-methyl-2-pyrrolidone is particularly preferable. The amount of the solvent used is preferably such that the concentration of the aromatic polyamide resin to be produced is 2 to 50% by weight, but considering the production efficiency and the solution viscosity with good operability, the amount to be 5 to 30% by weight. Particularly preferred. The reaction temperature in the condensation reaction is usually 60 to 150 ° C., preferably 70 to 120 ° C., and the reaction time is usually 1 to 15 hours, preferably 2 to 10 hours.

The aromatic polyamide thus obtained is usually represented by the following formula (1).

(In the formula, m and n are average values, 0.005 ≦ n / (m + n) <1, and m + n is a positive number from 0 to 230. Ar ₁ is a divalent aromatic group, Ar ₂ is a divalent aromatic group having a phenolic hydroxyl group, Ar ₃ is a divalent aromatic group)

In the above formula (1), the values of m and n are determined by the charging ratio of the aromatic diamine and the aromatic dicarboxylic acid, and the average value is usually n + m = 0 to 230, preferably 5 to 150.

The intrinsic viscosity value (measured with a 0.5 g / dl N, N-dimethylacetamide solution at 30 ° C.) of this aromatic polyamide resin having a preferred average degree of polymerization is in the range of 0.1 to 4.0 dl / g. . In general, whether or not the polymer has a preferable average degree of polymerization is determined by referring to the intrinsic viscosity. When the intrinsic viscosity is less than 0.1 dl / g, the film formability and the appearance of properties as an aromatic polyamide resin are insufficient, which may not be preferable. On the other hand, if the intrinsic viscosity is larger than 4.0 dl / g, there is a possibility that the degree of polymerization is so high that the solvent solubility is deteriorated and the molding processability is deteriorated.

In the production method of component (A), water is added to the reaction system after completion of the condensation reaction to hydrolyze the aromatic phosphite. The addition of water is usually performed by heating to 60 to 110 ° C., preferably 70 to 100 ° C. with stirring. The addition of water is continued under stirring until the oil layer and the aqueous layer begin to separate, but usually 10 to 230% by weight, preferably 20 to 150% by weight, is sufficient based on the total weight of the reaction solution. In order to sufficiently perform hydrolysis, it is preferable that water is added dropwise over 30 minutes to 15 hours, preferably 1 to 10 hours, rather than adding all the necessary amount at once. In this water dropping step, the aromatic phosphite is hydrolyzed to phosphate ions and phenols.

Stirring is stopped when the layer separation starts, and the mixture is allowed to stand, and when the upper layer (aqueous layer) and the lower layer (oil layer containing resin) are separated, the upper aqueous layer is removed. In this case, since the oil layer usually has a high viscosity and is in a slurry state, the water layer can be easily removed by decantation or the like. It is also possible to send liquid outside the system with a pump or the like. The aqueous layer contains impurities such as phosphoric acid, phosphorous acid, catalysts, phenols, pyridine derivatives, and a part of the solvent.

Since the oil layer left after the removal of the aqueous layer has partly removed the solvent and the viscosity increases and is difficult to handle, it is diluted by adding an organic solvent again. The organic solvent that can be used in this case is N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like. The amount of the solvent to be used is not particularly limited as long as the viscosity is sufficiently lowered, but is usually 5 to 100% by weight, preferably 10 to 80% by weight, based on the weight of the oil layer.

Next, the diluted oil layer is added to a poor solvent to precipitate an aromatic polyamide resin. The poor solvent is not particularly limited as long as it is a liquid that does not easily solvate with the aromatic polyamide resin, but specific examples include water, methanol, ethanol, and a mixed solvent thereof. The amount used is preferably as small as possible within the range in which the precipitated aromatic polyamide resin can be filtered out without any problem in operation, and is 0. 0 part by weight with respect to 1 part by weight of the solvent (including the dilution solvent) used in the reaction. 5 to 50 parts by weight is preferable, and 1 to 10 parts by weight is particularly preferable.

In mixing the diluted oil layer and the poor solvent, the poor solvent may be gradually added to the reaction solution with stirring, or the diluted solution of the oil layer may be added to the poor solvent with stirring. In the method of spraying the diluted liquid of the oil layer into the poor solvent using the liquid feed pump, the compressor and the two-fluid nozzle, or the liquid feed pump and the one-fluid nozzle, the aromatic polyamide resin having an appropriate particle diameter easily precipitates. preferable. The temperature at which the oil layer diluent and the poor solvent are mixed is usually 0 to 100 ° C., preferably 20 to 80 ° C.

The aromatic polyamide resin precipitated by mixing with a poor solvent is isolated by filtration, and ionic impurities are removed by washing the cake with water. An aromatic polyamide resin can be obtained by drying the cake, but ionic impurities can be further reduced by washing with a water-soluble organic solvent.

Examples of water-soluble organic solvents that can be used include alcohols such as methanol, ethanol, n-propanol, and isopropanol, and acetone. These may be used alone or in combination, with methanol being particularly preferred.

Washing with a water-soluble organic solvent is effective even if the polyamide resin cake isolated by filtration is washed on a filter, but it is wet, that is, an aromatic polyamide containing a good solvent and a poor solvent. The resin cake or the aromatic polyamide resin from which the good solvent and the poor solvent have been removed by drying and the water-soluble organic solvent are newly charged in a container, suspended by stirring, and then filtered again to further remove the cake. Excellent purification effect. In this case, the water-soluble organic solvent is used in an amount of 1 to 100 parts by weight, preferably 2 to 50 parts by weight with respect to 1 part by weight of the net polyamide resin, and the stirring temperature is from room temperature to the boiling point of the suspension. Stirring at the boiling point is particularly preferable. The stirring time is 0.1 to 24 hours, preferably 1 to 5 hours. Furthermore, this operation is usually performed under normal pressure, but can also be performed under pressure.

After the above suspension treatment, the polyamide resin is filtered off, usually further washed with a cake using the above water-soluble organic solvent, and then optionally further washed with water and then dried. Thus, a polyamide resin with less ionic impurities can be obtained.

The epoxy resin as the component (B) is not particularly limited as long as it has two or more epoxy groups in one molecule. Specifically, novolac type epoxy resin, dicyclopentadiene phenol condensation type epoxy resin, xylylene skeleton containing phenol novolak type epoxy resin, biphenyl skeleton containing novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbiphenol Examples thereof include, but are not limited to, type epoxy resins. Two or more of these epoxy resins can be used in combination.

In addition to the phenolic hydroxyl group-containing aromatic polyamide resin represented by the formula (1), other curing agents can be used in combination in the epoxy resin composition of the present invention. Specific examples of curing agents that can be used in combination include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride Acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac, phenol aralkyl, triphenylmethane and These modified products, imidazoles, BF3-amine complexes, guanidine derivatives and the like are exemplified, but not limited thereto. When these are used in combination, the proportion of the phenolic hydroxyl group-containing aromatic polyamide resin represented by the formula (1) in the total curing agent is usually 20% by weight or more, preferably 30% by weight or more.

Specific examples of the curing catalyst as component (C) include, for example, imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1, And tertiary amines such as 8-diaza-bicyclo (5,4,0) undecene-7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. If necessary, the curing catalyst is used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin.

Examples of the organic solvent that is the component (D) used in the thermal radiation paint of the present invention include γ-butyrolactones, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, Amide solvents such as N-dimethylacetamide and N, N-dimethylimidazolidinone, sulfones such as tetramethylene sulfone, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, propylene Ether solvents such as glycol monobutyl ether, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, toluene, xylene, etc. Although aromatic solvents including but not limited to these organic solvents. Any solvent that can uniformly dissolve and homogenize each component of the heat-radiating paint of the present invention can be used regardless of whether it is a polar or non-polar solvent. The organic solvent concentration in the thermal radiation coating material of the present invention is 30 to 2000 parts by weight with respect to 100 parts by weight in total of the phenolic hydroxyl group-containing aromatic polyamide resin (A), epoxy resin (B) and curing catalyst (C). In terms of% by weight, when the total composition is 100% by weight, it is usually 20 to 95% by weight, preferably 30 to 90% by weight. If the amount of the organic solvent used is extremely small, the viscosity becomes high and the coating property is lowered, and if it is extremely large, unevenness may occur during coating or a sufficient coating film may not be formed.

Further, the thermal radiation paint of the present invention includes a silane coupling agent, a release agent such as stearic acid, palmitic acid, zinc stearate, calcium stearate, a dispersing agent, a compatibilizing agent, a stabilizer, an antioxidant, and a surface modification agent. Various compounding agents such as an agent, an ultraviolet absorber, an antistatic agent and a pigment can be added and used within a range not impairing heat resistance, heat dissipation, insulation, surface smoothness and the like.

The thermal radiation paint of the present invention can be obtained by uniformly mixing the components (A), (B), (C), (D) and other components as necessary. As a mixing method, an Eirich mixer, a planetary mixer, a roll mill, a dissolver and the like can be used, but are not particularly limited.

The structure of the present invention having the layer of the heat-radiating paint can be obtained by applying the heat-radiating paint thus obtained to the outermost surface of the heat conductor as the adherend and drying it. Specifically, the obtained resin composition is applied to a heat conductor such as copper or aluminum by a roll coater, a bar coater, brush coating, spraying, roller dipping, ink jetting, printing or the like. In this case, in order to make the resin composition easy to adhere to the surface of the adherend, it is also possible to use an adherend that has been previously treated with an acid or alkali or physically roughened. The adherend is preferably a metal from the viewpoint of thermal radiation.
After the coating step, the organic solvent is further removed by heating and drying, and then the curing reaction of the high resin components (components (A) and (B)) is allowed to proceed, whereby the structure of the present invention can be obtained. .

The temperature for drying and curing is usually 50 to 300 ° C., particularly preferably 80 to 250 ° C. The time for drying and curing is usually 5 minutes to 3 hours, preferably 10 minutes to 2 hours. For paints with a high content of component (D), a drying process is preferred in which the coating is dried at a relatively low temperature and the temperature is increased as the component (D) decreases. Care should be taken because it may cause The thickness of the dried coating film is usually 0.5 to 300 μm, preferably 2 to 230 μm. If the coating film is too thin, the metal casing will be partially exposed when processing later, and will not be fully effective. If it is too thick, the thermal resistance between the metal casing and the coating surface will increase, and the surface heat will increase. Regardless of the radiation, the rapid heat conduction from the metal casing to the coating surface is inhibited.

The thermal radiation paint of the present invention does not contain an inorganic filler, and the surface after coating and drying on a metal casing is smooth and uniform. Moreover, since the inorganic filler is not included, even when the paint is stored for a long period of time, non-uniformity such as sedimentation of the inorganic filler does not occur. Therefore, the thermal radiation paint of the present invention is a paint having excellent workability without requiring an operation such as stirring and mixing before coating. Moreover, since the thermal radiation coating material of the present invention has a polyamide skeleton as a main component, it has high heat resistance and excellent insulating properties.

Hereinafter, the present invention will be described in more detail with reference to examples.
The present invention is not limited to these examples. In the following, the active hydrogen equivalent of the polyamide resin is the average mass of the compound per hydroxyl group and terminal active hydrogen, and the epoxy equivalent is the mass of the epoxy resin per epoxy group, and the hydroxyl equivalent Is the mass of the compound per hydroxyl group (OH group).
In the following, “parts” and “%” are based on weight unless otherwise specified. In addition, the thermal radiation test is a structure that is excellent in heat dissipation by measuring the temperature at a certain distance from the part heated to a certain temperature of the metal substrate coated and dried with the thermal radiation resin by the presence or absence of the application of the thermal radiation resin. The measured temperature is lowered. In addition, the amount of applied electric power for keeping the applied heating unit constant increases as the structure has better heat dissipation, and decreases as the heat dissipation decreases.

Formulation Example 1
A phenolic hydroxyl group-containing aromatic polyamide resin represented by the formula (1) (Ar ₁ : isophthalic acid residue, Ar ₂ : 5-hydroxyisophthalic acid residue, Ar ₃ : 3,4′-diaminodiphenyl ether residue, n = 2 and m = 198 Nippon Kayaku Co., Ltd. product name CPAM-750, hydroxyl group equivalent 4900 g / eq.), Γ-butyrolactone, epoxy resin (biphenyl-phenol condensation type epoxy resin, Nippon Kayaku Co., Ltd. product name NC) -3000, epoxy equivalent 280 g / eq.), Curing agent (biphenyl-phenol condensation resin, Nippon Kayaku Co., Ltd., trade name GPH-65, hydroxyl group equivalent 203 g / eq.), Curing catalyst (imidazole-based curing catalyst, Shikoku Chemicals) The product name C11Z-A) made by Co., Ltd. was added while being dissolved in order according to the composition distribution shown in Table 1. To obtain a heat radiation paint color transparent present invention. The viscosity of this paint with an E-type viscometer at 25 ° C. was 153 cPs.

Example 1
After the surface is sufficiently degreased and washed, using a polyimide tape and masking so that an uncoated part of 50 mm square is formed at the center of one side of the surface untreated aluminum substrate having a width of 50 mm, a length of 250 mm and a thickness of 1 mm, The heat-radiating paint obtained in Formulation Example 1 was applied to the entire front and back surfaces using a spray gun. Next, it was put into a circulation oven set at 150 ° C. and dried for 10 minutes. Further, after repeating the above spray coating and drying operations twice, it was dried and cured in a circulation oven set at 170 ° C. for 1 hour, and the coating thickness A heat dissipation structure having a thickness of 25 μm was obtained. Next, the central polyimide tape masking part of the obtained structure was peeled off and a film-like thermocouple for temperature control was adhered, and a film heater (40 V, 50 W) of 50 mm square and 200 μm thickness, aluminum of 50 mm square and 1 mm thickness. Two plates were stacked one on top of the other and the four sides were fixed with clips. Next, a film type thermocouple for temperature measurement was adhered to the center of the surface of both end portions 110 mm away from the center of the test piece with a clip coated with Teflon (registered trademark) to prepare a thermal radiation measurement sample. Next, the test structure capable of measuring heat is placed in a box that is not easily affected by temperature, wind, heat reflection, etc. from the outside, and a conductive wire from a power supply power source is connected to the film heater via a temperature controller. The temperature measuring thermocouples at both ends were connected to a temperature recorder. Next, Table 1 shows the average temperature at both ends when the center of the test piece is heated by setting the heater set temperature 180 ° C. and the heater applied voltage 40 V and the temperature at the ends is sufficiently stabilized. Table 1 shows the voltage when the heater applied voltage was adjusted and the temperature controller was adjusted to a voltage capable of maintaining 180 ° C. with almost no on / off of the temperature controller.

Also, the thermal radiation coating material obtained in Formulation Example 1 was applied to release PET, (PET-38AL5 (manufactured by Lintec Corporation)) using a bar coater so that the thickness after drying was 25 μm, and then 150 After drying at 30 ° C. for 30 minutes, it was peeled off from the release PET and further dried and cured at 170 ° C. for 1 hour to obtain a thermal test sample. Next, the obtained test piece was cut to a width of 10 mm, and measured using a viscoelasticity measuring device DMS6100 (manufactured by SII Nanotechnology Co., Ltd.) at a heating rate of 5 ° C./min. The temperature is shown in Table 1.

Example 2
In Compounding Example 1, as an epoxy resin, a cresol novolac type epoxy resin (trade name EOCN-1020, epoxy equivalent of 280 g / eq, manufactured by Nippon Kayaku Co., Ltd.) and a phenol novolac type resin H-1 (manufactured by Meiwa Kasei Co., Ltd.) as a curing agent A hydroxyl group equivalent of 105 g / eq) was blended in the same manner as in Blending Example 1 except that the composition distribution shown in Table 1 was blended to obtain a thermal radiation paint having a viscosity of 140 cPs with an E-type viscometer at 25 ° C. Example 2). Table 1 shows the results obtained by coating and curing in the same manner as in Example 1 and preparing thermal radiation measurement samples and viscoelasticity measurement test pieces and evaluating in the same manner as in Example 1.

Example 3
An E-type viscometer at 25 ° C. was blended in the same manner as in Blending Example 1, except that NC-3000 as an epoxy resin, GPH-65 as a curing agent, and C11Z-A as a curing catalyst were blended in the composition distribution shown in Table 1. A thermal radiation coating with a viscosity of 153 cPs was obtained (Formulation Example 3). Table 1 shows the results of coating, drying and curing in the same manner as in Example 1 and producing thermal radiation measurement samples and viscoelasticity test specimens and evaluating them in the same manner as in Example 1.

Comparative Example 1
Table 1 shows the heat dissipation when evaluated in the same manner as in Example 1 with a film heater attached to an untreated aluminum substrate on which no resin composition was applied to the surface.

Comparative Example 2
γ-butyrolactone, epoxy resin NC-3000, curing agent GPH-65, and curing catalyst C11Z-A were blended in the composition distribution shown in Table 1 to prepare a resin composition that does not contain a phenolic hydroxyl group-containing aromatic polyamide resin. A comparative paint having a viscosity of 121 cPs with an E-type viscometer at ° C. was obtained (Comparative Comparative Example). Table 1 shows the results of coating, drying, curing and evaluation in the same manner as in Example 1. The viscoelasticity measurement is fragile in a film and cannot be set in a measuring device. Therefore, an uncured film peeled off from the release PET after drying is layered, and further, press-cured at 170 ° C. for 1 hour to obtain a 2 mm thick test piece. Created and measured.

In Table 1, the abbreviations indicate the following.
A: Aromatic polyamide resin containing phenolic hydroxyl group: CPAM-750
B: Epoxy resin: NC-3000
C: Epoxy resin: EOCN-1020 epoxy equivalent 195)
D: Curing agent: GPH-65
E: Curing agent: H-1
F: Curing catalyst: C11Z-A

As is clear from Table 1, the heat radiation paint of the present invention and the structure obtained by coating and drying the heat radiation paint of the present invention have extremely low end temperatures. Moreover, since the heat of the heat generating part can be quickly released to the outside, a larger applied voltage is required to keep the heating part at a constant temperature. For these reasons, it is possible to keep the temperature of the heat generating part lower even under high load by connecting with various heat generating elements. Therefore, the structure obtained by coating and drying and curing the thermal radiation paint of the present invention is expected to be used in power devices in the fields of electricity, electronics, automobiles, etc., particularly in the fields of high output inverters, high output motors, etc. .

Claims

Following formula (1)

(In the formula, m and n are average values, 0.005 ≦ n / (m + n) <1, and m + n is a positive number from 0 to 230. Ar 1 is a divalent aromatic group, Ar 2 is a divalent aromatic group having a phenolic hydroxyl group, Ar 3 is a divalent aromatic group), and a phenolic hydroxyl group-containing aromatic polyamide resin (A) or epoxy resin (B) having a structure represented by A heat-radiating paint comprising 30 to 2000 parts by weight of an organic solvent (D) with respect to 100 parts by weight of the total of the curing catalyst (C).
Ar 1 in the compound of the formula (1) is a residue of one or more acids selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, succinic acid and fumaric acid, Ar 2 is 5-hydroxyisophthalic acid, 4- A residue of at least one acid selected from the group consisting of hydroxyisophthalic acid, 2-hydroxyphthalic acid, 3-hydroxyphthalic acid, and Ar 3 is 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 2. The thermal radiation paint according to claim 1, which is a residue of one or more amines selected from the group consisting of 4,4′-diaminodiphenyl ether.
The thermal radiation paint according to claim 1 or 2, which does not contain an inorganic filler.
A structure having a layer obtained by applying the heat-radiating paint according to any one of claims 1 to 3 to the outermost surface of the heat conductor, drying and curing.
The structure according to claim 4, wherein the thickness of the coating film of the thermal radiation coating layer is 0.5 to 300 µm.