JPH07238240A - Photo-setting moisture-proof insulation coating and production of moisture-proof insulated electronic part - Google Patents

Abstract

PURPOSE:To obtain a photo-setting moisture-proof insulation coating material having excellent curability and moisture resistance, causing little loss of flexibility even after thermal deterioration and suitable for electronic part having excellent heat resistance and improved reliability. CONSTITUTION:This photo-setting moisture-proof insulation coating material contains (A) a photo-setting acryloxy-terminated polybutadiene or methacryloxy- terminated polybutadiene having a number-average molecular weight of 300-10,000 and a hydrogenation ratio of >=90%, (B) a wax and (C) tetra-t- butylperoxycarbonylbenzophenone. This process for the production of a moisture- proof insulated electronic part comprises the coating and curing of the coating material on an electronic part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable moisture-proof insulating coating suitable for moisture-proofing and insulating electronic parts and a method for producing electronic parts treated with the same.

[0002]

2. Description of the Related Art Conventionally, a mounting circuit board and a hybrid I
Electronic components such as C (integrated circuit) are printed with a wiring diagram on a substrate such as glass epoxy, paper phenol, and alumina ceramic, and various components such as a microcomputer, a resistor, and a capacitor are mounted. Insulation is performed to protect it from dust. For this insulation treatment method, a protective coating treatment using a paint such as acrylic resin, silicone resin, phenol resin, or epoxy resin is widely adopted. Such a mounting circuit board and a hybrid IC are used in a harsh environment, particularly under high humidity, and are mounted and used in equipment such as an automobile and a washing machine.

[0003]

However, since the coating material is heat-curable, high temperature treatment and long-time treatment are required to completely cure the coating material and obtain an insulating effect. On the other hand, an ultraviolet curable resin coating composition that can be cured in a short time, for example, in a few seconds to a few minutes has been developed, but a coating material having sufficient flexibility and moisture resistance has not yet been obtained. In addition, a portion such as a lower portion of the mounted component which is not irradiated with ultraviolet rays is in a liquid state and is in an uncured state, and there is a possibility that reliability of the electronic component is deteriorated. The present invention solves the above-mentioned problems of the prior art, can be treated for a short time, and produces a coating film excellent in flexibility and moisture resistance. It is an object of the present invention to provide a method of manufacturing a moisture-proof insulated electronic component.

[0004]

The present invention provides (A) a number average molecular weight of 300 to 10,000 and a hydrogenation rate of 90%.
The above photocurable moisture-proof insulating coating material containing photocurable terminal acryloxypolybutadiene or methacryloxypolybutadiene terminal, (B) wax and (C) tetratertiarybutylperoxylcarbonylbenzophenone, and this coating material for electronic parts The present invention relates to a method for manufacturing a moisture-proof insulated electronic component which is applied and cured on a substrate.

The photocurable terminal acryloxy polybutadiene or methacryloxy polybutadiene (A) having a hydrogenation rate of 90% or more used in the present invention is obtained by converting a terminal hydroxypolybutadiene having a hydrogenation rate of 90% or more into a polyisocyanate. With a number average molecular weight of 300 to 1 obtained by reacting with hydroxyethyl acrylate or hydroxyethyl methacrylate.
It is 20,000 acrylic modified hydrogenated polybutadiene resin. The number average molecular weight of this resin is 300 to 10,000.
0, preferably 500 to 5,000, the hydrogenation rate is 90
% Or more, preferably 95% or more. When the number average molecular weight is less than 300, the film-forming property is poor, and when it exceeds 10,000, the viscosity is high and the workability is poor. The hydrogenation rate is 9
If it is less than 0%, the flexibility of the coating film obtained after heating is deteriorated and the heat resistance is poor. Commercially available products of this acryl-modified hydrogenated polybutadiene resin include trade names TEAI-1000 and TEAI-3000 manufactured by Nippon Soda Co., Ltd. These can be used alone or in combination of two or more.

The wax (B) used in the present invention is a natural wax or a synthetic wax such as carnauba wax, rice wax, beeswax, paraffin wax and microcrystalline wax which is solid at room temperature and has extremely low volatility when melted. is there. These can be used alone or in combination of two or more. The blending ratio of the wax (B) is preferably from 5 to 100 parts by weight, more preferably from 10 to 50 parts by weight based on 100 parts by weight of the component (A) from the viewpoint of preventing stickiness and flexibility of the coating film. preferable.

The tetratertiarybutylperoxylcarbonylbenzophenone (C) used in the present invention is a photopolymerization initiator having a benzophenone group which is an ultraviolet absorbing group and a peroxy group which is easily radically cleaved in the same molecule. The blending ratio of the component (C) is 0.01 with respect to 100 parts by weight of the component (A) from the viewpoint of curing rate and film-forming property.
The range of 10 to 10 parts by weight is preferable, and the range of 0.1 to 7 parts by weight is more preferable.

The photocurable moisture-proof insulating coating material of the present invention is obtained by blending the components (A), (B) and (C) described above and heating and dissolving them. In addition, a crosslinkable monomer, a silane coupling agent, a polymerization inhibitor, etc. can be added to the photocurable moisture-proof insulating coating material of the present invention, if necessary.

Examples of the crosslinkable monomer include styrene, vinyltoluene, α-methylstyrene, p-tert-butylstyrene, chlorostyrene, divinylbenzene, diallylphthalate, 2-hydroxyoxymethacrylate and 2-hydroxypropylmethacrylate. , A monofunctional methacrylic acid ester such as a reaction product of methyl methacrylate, ethyl methacrylate, lauryl methacrylate, methacrylic acid and Cardura E-10 (trade name of glycidyl ester of higher fatty acid, manufactured by Shell Chemical Co., Ltd.),
Bifunctional methacrylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and 1,6-hexanediol dimethacrylate, trifunctional methacrylic acid esters such as trimethylolpropane trimethacrylate, methyl acrylate, ethyl acrylate, and lauryl acrylate. , 2-
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylic acid and Cardura E-10
Reaction products such as monofunctional acrylic acid esters, ethylene glycol diacrylate, diethylene glycol diacrylate, difunctional acrylic acid esters such as 1,6-hexanediol diacrylate, trifunctional compounds such as trimethylolpropane triacrylate. Acrylic acid esters and the like are used, and these can be used alone or in combination of two or more kinds.

Examples of the silane coupling agent include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane. Can be mentioned.
These can be used alone or in combination of two or more.

As the polymerization inhibitor, quinones such as hydroquinone, paratertiary butyl catechol and pyrogallol, and other commonly used ones can be used.

Electronic components such as mounted circuit boards and hybrid ICs, which are moisture-proof insulated using the photocurable moisture-proof insulating coating material according to the present invention, are manufactured by a generally known brush coating method. The coating material may be applied to the electronic component and cured by a dipping method (dip method), a spray method, or the like. Curing of the coating film after coating is performed by ultraviolet irradiation.

[0013]

EXAMPLES The present invention will now be described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Those expressed as "parts" indicate parts by weight. Example 1 TEAI-1000 (manufactured by Nippon Soda Co., Ltd., acrylic modified hydrogenated polybutadiene resin, number average molecular weight: about 1,
000, hydrogenation rate: 97%) 100 parts, carnauba wax 30 parts and tetratertiarybutylperoxylcarbonylbenzophenone 5 parts were mixed and stirred at a temperature of 80 ° C. to obtain a paint A.

COMPARATIVE EXAMPLE 1 TE-2000 (manufactured by Nippon Soda Co., Ltd., terminal methacryloyl group polybutadiene resin, number average molecular weight: about 2,000)
0) 100 parts, 5 parts of benzyl dimethyl ketal and 100 parts of toluene were mixed and stirred at a temperature of 50 ° C. to obtain a coating material B. Comparative Example 2 TEAI-1000 (manufactured by Nippon Soda Co., Ltd., acrylic modified hydrogenated polybutadiene resin, number average molecular weight: about 1,
000, hydrogenation ratio: 97%) and 5 parts of tetratert-butylperoxylcarbonylbenzophenone were mixed and stirred at a temperature of 100 ° C. to obtain coating C.

The coating materials A to C obtained as described above are applied by dipping onto a mounting circuit board on which wiring is printed on a glass epoxy copper clad laminate and ICs and resistors are mounted. Irradiation output manufactured by USHIO INC. Was irradiated with ultraviolet rays from a mercury lamp of 50 W / cm for 10 seconds from an irradiation distance of 10 cm to prepare a test piece for evaluation of curability, and the curability was tested. In addition, these paints were applied to a glass epoxy copper clad laminate comb-type electrode (electrode spacing 0.3 mm) by the dipping method and cured under the above curing conditions to prepare a test piece for a moisture resistance test, and a moisture resistance test piece was prepared. Tested for sex. Furthermore, regarding these test pieces, JIS C 21
A test piece for bending test was prepared in accordance with No. 03, cured under the above curing conditions, and allowed to stand at 80 ° C. for 100 hours to test the flexibility. The results are shown in Table 1. When the coating materials A and C were applied by the dipping method, the coating materials A and C were heated to 80 ° C. before use. Further, the humidity resistance is such that the test piece for humidity resistance test is left to stand in a constant temperature and humidity tank at 85 ° C. and 85% RH while applying DC14V, and taken out from the constant temperature and humidity tank for each standing time shown in Table 1 for 2 hours. Then, DC500V was applied at 23 ° C., and the insulation resistance was measured and evaluated.

[0016]

[Table 1]

[0017]

As shown in Table 1, the photocurable moisture-proof insulating coating material according to the present invention is excellent in curability and moisture resistance, and has heat resistance that hardly deteriorates flexibility even when deteriorated by heating. It is an excellent paint, and it is possible to manufacture electronic parts with improved reliability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01L 23/31 H05K 3/28 D // C08F 2/50 MDQ 299/00 MRN (72) Inventor Eiji Omori 4-13-1, Higashi-cho, Hitachi-shi, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Yamazaki factory

Claims (2)

[Claims] 1. (A) Number average molecular weight of 300 to 10,0
00, a photocurable resin containing a photocurable terminal acryloxypolybutadiene or methacryloxypolybutadiene having a hydrogenation rate of 90% or more, (B) wax and (C) tetratertiarybutylperoxylcarbonylbenzophenone. Moisture-proof insulating paint. 2. A method for producing a moisture-proof insulated electronic component, which comprises applying the photocurable moisture-proof insulating coating composition according to claim 1 to an electronic component and curing it.