KR0146384B1 - Epoxy resin powder coating composition - Google Patents

Abstract

Mixed epoxy resin composed of bisphenol epoxy resin and novolac epoxy resin, and the following formula (I)

(In formula, n represents the integer of 0-8.)

It consists of combining the hardening agent which consists of a diphenylol derivative represented by this, and a nylon fine powder and a silica fine powder whose melting | fusing point is 200 degreeC or more, and an average particle diameter is 18-50 micrometers, nylon fine per 100 weight part of this melting point epoxy resin A flexible epoxy resin powder coating composition, wherein the compounding amount of the powder is 5 to 30 parts by weight and the compounding amount of the silica fine powder is 100 to 200 parts by weight.

Description

Epoxy Resin Powder Coating Composition

The present invention relates to a flexible epoxy resin powder coating composition. The composition of the present invention provides a coating having excellent moisture resistance, heat resistance, chemical resistance, adhesive strength, and heat cycle resistance, particularly when applied as a powder coating, and thus, electronic components such as ceramic capacitors, resistance networks, and hybrid ICs. It is suitable as powder coating for insulating encapsulation of coil parts such as inductors and the like.

As an epoxy resin coating material used for insulating coatings of ceramic capacitors and inductor coils, Japanese Patent Laid-Open No. 1-210419 discloses epoxy resins and diphenyls composed of bisphenol-type epoxy resins and noblock type epoxy resins as derivatives and accelerators. It is proposed that consists of.

However, the performance of such a composition is not yet sufficiently satisfactory, and in particular, there is room for improvement in terms of durability and mechanical resistance to mechanical shock and thermal shock.

It is an object of the present invention to solve the above problems seen in the prior art and to provide an epoxy resin composition which is excellent in moisture resistance and heat resistance, and also excellent in durability against mechanical shock and thermal shock.

According to the present invention, 100 wt% of mixed epoxy resin is composed of 40 to 80 wt% of bisphenol type epoxy resin having a weight of 180 to 2500 per epoxy and 60 to 20 wt% of novolac epoxy resin having a weight of 180 to 230 per epoxy. part; 0.6-1.5 equivalents of the following formula (I) per 1 equivalent of epoxy group of the mixed epoxy resin:

(In formula, n represents the integer of 0-8.)

Curing agent containing derivative which diphenyl represented by; 0.2 to 5 parts by weight of a curing accelerator; 5-30 weight part of nylon fine powders whose melting | fusing point is 200 degreeC or more and whose average particle diameter is 18-50 micrometers; And 100 to 200 parts by weight of silica fine powder having an average particle diameter of 1 to 50 µm.

The mixed epoxy resin used in the present invention is a mixture of a bisphenol type epoxy resin and a novolak type epoxy resin, and is solid at room temperature. Melting | fusing point of mixed epoxy resin should just be in the range of 50-90 degreeC normally, and if it is this range, when used as powder coating material, the viscosity at the time of melting is suitable, the appearance of coating film is favorable, and the surface roughness and sag do not arise and it is smooth One coat can be obtained.

Bisphenol type epoxy resins are diglycidyl ethers of bisphenols, and known bisphenols such as A-type and F-type are used, and it is particularly preferable to use A-type ones. Novolak-type epoxy resins are glycidyl ethers of novolacs, and known novolacs such as phenol novolaks and cresol novolacs are particularly preferable. It is preferable to adjust the compounding ratio of both to adjust the epoxy equivalent of the mixed epoxy resin in the range of 350-1000. Preferred mixed epoxy resins in the present invention are composed of 40 to 80% by weight of epoxy equivalent 180 to 2500 bisphenol A epoxy resin and 20 to 60% by weight of cresol novolac epoxy resin having an epoxy equivalent of 180 to 250. The equivalent is 350-1000, and melting | fusing point is 50-90 degreeC.

The composition of this invention contains the diphenyl derivative represented by the said Formula (I). In the diphenylol derivative represented by this formula (I), although the polymerization degree n is 0-8 normally, Preferably it is 0-6. By mix | blending such a hardening | curing agent, it becomes excellent in flexibility, a crosslinking density is high, and a hardened | cured material with a glass transition point of 100 degreeC or more can be obtained. The amount of the curing agent used is 0.6 to 1.5 equivalents, preferably 0.7 to 1.2 equivalents, per epoxy equivalent of the mixed epoxy resin.

The composition of the present invention contains silica fine powder. Examples of the silica fine powder include fused silica (including spherical products), crystalline silica, and the like, and preferably crushed fused silica particles are used. The average particle diameter of silica fine powder is 1.0-50 micrometers, Preferably it is 10-35 micrometers. The silica fine powder may be surface treated with a silane coupling agent. In this case, examples of the silane coupling agent include epoxysilane, 2- (3,4-epoxycyclohexane) -ethyltrimethoxysilane, 3-glycidoxy propyl methoxy silane, and the like.

In the present invention, the silica fine powder is used in an amount of 100 to 200 parts by weight, preferably 130 to 180 parts by weight, based on 100 parts by weight of the mixed epoxy resin.

In the present invention, the silica hydrophobic powder having high hydrophobicity is used in a large amount, but the composition in which hygroscopicity is suppressed by the use of such a large amount of silica micropowder can be obtained, and a cured product excellent in moisture resistance can be obtained. .

The composition of the present invention contains a nylon fine powder having a melting point of 200 占 폚 or higher.

As such a nylon fine powder, the fine powder of 6-nylon (melting point 211 degreeC) and 6,6-nylon (melting point 273 degreeC) is mentioned. Nylon having a melting point lower than 200 ° C. is not preferable because the heat resistance of the cured product is impaired. The average particle diameter of nylon fine powder is 18-50 micrometers, Preferably it is 18-30 micrometers.

Nylon microspray is used in the ratio of 5-30 weight part, Preferably it is 5-20 weight part with respect to 100 weight part of mixed epoxy resins. Nylon fine powder gives the hardened | cured material buffer property and toughness, and shows the effect which improves durability to a mechanical shock or a thermal shock of hardened | cured material.

The composition of the present invention contains a curing accelerator. As a hardening accelerator, a conventional thing, for example, imidazole type, such as 2-methylimidazole, 2,4-diamino-6- [2-methylimidazole- (1)] ethyl-s-triazine, and dicyandi Amides such as amides, Diazas such as 1,8-diaza-bicyclo (5,4,0) undecene-7 and salts thereof, and phosphines such as triphenyl phosphine are used. It is preferable to use a phosphine type thing from the point which provides hardened | cured material with favorable flexibility. The compounding ratio of these hardening accelerators is a ratio of 0.2-3.0 weight part with respect to 100 weight part of mixed epoxy resins.

The composition of this invention can contain the auxiliary component as shown below as needed besides the said essential component.

[Water repellent]

As the water repellent, conventionally known compounds exhibiting water repellency are used, but in general, a silane coupling agent is used. As the silane coupling agent, for example, use of epoxysilane, 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, 3-glycidoxypropyl methoxysilane, or the like is preferable. The addition amount of a silane coupling agent is 0.5-6 weight part with respect to 100 weight part of silica, Preferably it is the ratio of 0.5-1.5 weight part.

[Flame retardant]

As a flame retardant, a conventionally well-known thing, for example, the combination of a brominated aromatic compound and antimony trioxide can be used. In this case, for example, hexabrombenzene, bromine phenol, hexa bromine diphenol, decabromodiphenyl, or the like can be cited as the aromatic aromatic compound. Antimony trioxide is used in the ratio of 0.3-0.7 weight part, Preferably it is about 0.5 weight part with respect to 1 weight part of brominated aromatic compounds. The brominated aromatic compound and antimony trioxide may be used in an amount of 15 to 40 parts by weight, preferably 20 to 25 parts by weight, based on 100 parts by weight of the mixed epoxy resin. In general, when the thickness of the cured resin film is 0.5 mm or more, such a flame retardant can be obtained a flame retardant composition having the characteristics of V-0 and having an oxygen index of 32 or more in the combustibility test by the UL 94 method.

[Mucking Agent]

As a merking agent, a conventionally well-known thing, for example, basic lead amine acid, basic copper carbonate, basic lead sulfite, etc. are used. The mucking agent is used in the ratio of 5-50 weight with respect to 100 weight part of mixed epoxy resins. The merking agent is described in detail in, for example, Japanese Patent Publication No. 4-1709.

In addition to the above auxiliary components, the composition of the present invention may further contain a conventional auxiliary shelf, a leveling agent such as an acrylic ester oligomer, thixotropic agents such as polyvinyl butyral, various coloring agents and the like.

When using the composition of this invention as a powder coating material, after mix | blending each compounding component with a mixer etc. according to the conventional method, what is necessary is just to solidify, and to grind | pulverize the mixture obtained by melt-mixing with a corneader etc. finely.

Next, the present invention will be described in more detail with reference to Examples.

Example 1

The powder coating material of the component composition (weight part) shown in Table 1 was prepared by the conventional method.

Next, each composition obtained above was about 0.5 mm thick by a powder coating machine (PC-25, Seigen Co., Ltd.) on the surface of a polyester film capacitor element having a capacitance of 0.01 kPa having two lead wires. The cured coating film of was formed and the capacitor element coating material was obtained. In this case, 60 minutes of conditions were used as 120 degreeC as hardening conditions.

Next, the capacitor element coating material obtained as mentioned above was used as a sample for performance evaluation, and the following items were evaluated.

(1) lead wire strength

The two lead wires were pulled in opposite directions by a universal testing machine (Tenshiron UTM-5000, manufactured by Orietec Co., Ltd.) with respect to a sample without a coating defect, and the tension when the lead wires detached from the coating material The stress was measured. The larger the tensile stress at this time, the better the adhesion between the coating film and the lead wire and the better the coating film quality. Table 1 shows his test results. This test result showed the average value about ten samples.

(2) moisture resistance

After leaving the sample without a coating film defect in the pressure cooking test apparatus for 48 hours under the conditions of the temperature of 120 degreeC, and 95% of a relative humidity, the sample was taken out from the apparatus and the weight increase (%) before and behind a test was computed. It shows that the water absorption of a cured coating film is large and this moisture resistance is inferior as this value is large. Table 1 shows his test results. This test result showed the average value about ten samples.

(3) heat resistance

After leaving the sample without coating defects for 60 hours in a thermostatic bath controlled at 60 ° C. and 95% RH, it was immersed for 120 seconds in a silicone oil bath adjusted to a predetermined temperature (150 to 200 ° C.) It was taken out, cooled naturally at room temperature and cooled to room temperature. Regarding this cooling sample, it was judged whether the crack formed in the coating film by the optical microscope. The number of the sample which has a crack in ten samples was investigated, and the number is shown in Table 1. The smaller the number, the better the heat resistance of the protective coating film.

And the compounding component shown in Table 1 is as follows.

Epicoat 1001... … Bisphenol A type epoxy resin (epoxy equivalent 475) (made by Eucacel Epoxy)

Epicoat 1002. … Bisphenol A epoxy resin (Epoxy equivalent 650) (made by Eucacel Epoxy)

EOCN 104... … Ortho cresol novolac epoxy resin (epoxy equivalent 235) (made by Nippon Kaya Co., Ltd.)

Fusex RD8… … Crushed Fused Silica (Average Particle Size 13µm) (manufactured by Tatsumori Corporation)

Epicure EK-171N… … Diphenylol propane polymer (in the general formula (I), the mixture is n = 0 to 8, and the main component is a compound of bisphenol A and n = 2, hydroxyl group equivalent 220) (manufactured by Eucacel Epoxy)

PP-360... … Triphenylphosphine (manufactured by KEAI AG Co., Ltd.)

Daminol 754… … Phenolic borax resin (hydroxyl equivalent 105) (Arakawa Chemical Co., Ltd.)

Curazole 2MZ-A. … 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl S-triazine (manufactured by Kogo Chemical Co., Ltd.)

Nylon 6.. … Melting point 211 ° C., average particle size 20 μm (Coulter counting method)

Red pigment (iron oxide): 0.15 ㎛ average particle size by BET method (manufactured by Toda Kogyo Co., Ltd.)

Silane coupling agent. … γ-glycidoxypropyl trimethoxysilane (manufactured by Jiso Corporation)

Moreover, melting | fusing point (mp) of nylon was measured by the thermal analysis apparatus TA-4000 / DSC20S differential calorimeter made from Metra Corporation. In this case, melting | fusing point was made into the main peak top temperature.

* A comparative example is shown.

Example 2

Epicoat 1001: 30 parts by weight, Epicoat 1002: 30 parts by weight, EOCN 104: 40 parts by weight, Fusex RD-8: 150 parts by weight, Epicure EK-171: 60 parts by weight, PP-360: 1.8 parts by weight , Basic lead phosphite (merking material): 30 parts by weight, iron (III) oxide red pigment: 3 parts by weight, silane coupling agent: 1.5 parts by weight, various nylon fine powders having an average particle diameter of 20 μm shown in Table 3 to 10 parts by weight. The powder coating thus formed was prepared by a conventional method. This powder coating was evaluated in the same manner as in Example 1 to evaluate its performance. The results are shown in Table 2.

And in the heat resistance evaluation result shown in Table 2, code | symbol B shows that the nylon in a cured coating film was dropleted, and was bridled to the cured coating film surface.

* A comparative example is shown.

Example 3

Epicoat 1001: 30 parts by weight, Epicoat 1002: 30 parts by weight, EOCN 104: 40 parts by weight, Fusex RD-8: 150 parts by weight, Epicure EK-171: 60 parts by weight, PP-360: 1.8 parts by weight , Basic lead phosphite (merking material): 30 parts by weight, iron (III) oxide red pigment: 3 parts by weight, silane coupling agent: 1.5 parts by weight, fine powder of nylon 6 having various particle sizes shown in Table 3: 10 parts by weight Powder coating was prepared by a conventional method. The powder coating was investigated for its melt horizontal flow rate and coating film defects as follows, and the heat wire strength, heat resistance, and halide cycleability were evaluated in the same manner as in Example 1. The results are shown in Table 3.

(Melt horizontal flow rate)

1.4 g of powder coating samples were molded into tablets having a diameter of 16 mm, placed on a mild steel plate, melt-gelled in a furnace at 140 ° C., and their spreading diameters (L) were measured to determine the melt horizontal flow rate (R1) by the following equation. Calculated.

R1 (%) = (L-16) / 16 × 100

(Defective coating)

In the same manner as in Example 1, powder coating was applied to the surface of the film capacitor element to form 50 coatings, and the surface and the back surface of these coatings were observed and determined by an optical microscope. It was judged that there was a coating-film defect which had a pinhole defect in either the surface or the back surface. Table 3 shows the number of samples with coating film defects in 50 samples.

* A comparative example is shown.

Claims (3)

100 parts by weight of a mixed epoxy resin composed of 40 to 80% by weight of a bisphenol type epoxy resin having a weight of 180 to 2500 per epoxy and 60 to 20% by weight of a novolak type epoxy resin having a weight of 180 to 230 per epoxy; 0.6-1.5 equivalents of the following formula (I) per 1 equivalent of epoxy group of the mixed epoxy resin: (In formula, n represents the integer of 0-8.) Curing agent containing derivative which diphenyl represented by; 0.2 to 5 parts by weight of a curing accelerator; 5-30 weight part of nylon fine powders whose melting | fusing point is 200 degreeC or more and whose average particle diameter is 18-50 micrometers; And 100 to 200 parts by weight of silica fine powder having an average particle diameter of 1 to 50 µm. The composition of claim 1 wherein the mixed epoxy resin has a weight of 350 to 1000 per epoxy. The composition according to claim 1 or 2, wherein the bisphenol type epoxy resin is a bisphenol A type epoxy resin and the novolak type epoxy resin is a cresol type novolac epoxy resin.