JPH08165454A - Heat-resistant moistureproof insulation coating and production of insulated electronic part - Google Patents

Abstract

PURPOSE: To provide a heat-resistant moistureproof insulation coating having excellent heat-resistance to prevent the lowering of the flexibility of coating film even after thermal deterioration at a high temperature and giving an insulated electronic part having high reliability. CONSTITUTION: This heat-resistant moistureproof insulation coating contains (A) a polymer produced by reacting (a) 100 pts.wt. of a hydroxyl-containing polybutadiene with (b) 30-300 pts.wt. of a hydroxyl-containing hydrogenated polybutadiene and (c) a polyisocyanate at a ratio of 0.7-1.5mol of the isocyanate group based on 1mol of the hydroxyl group of the components (a) and (b), (B) 10-100 pts.wt. of a tackifier and (C) a solvent. The invention also relates to a process for producing an electronic part using the coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof insulating coating having excellent heat resistance suitable for insulating electronic parts and a method for producing an electronic part subjected to an insulation treatment.

[0002]

2. Description of the Related Art Electric equipment tends to be smaller and lighter and has more and more functions year by year, and mounted circuit boards mounted on various electric equipments for controlling the electric equipment have insulation treatment for the purpose of protection from moisture, dust, gas and the like. Has been done. This insulation treatment method includes acrylic resin, silicone resin and Japanese Patent Publication No. 26354.
The protective coating treatment with a paint such as urethane resin described in Japanese Patent Publication is widely adopted. Such a mounting circuit board is used in a harsh environment, especially under high humidity, and is mounted and used in equipment such as a washing machine and an automobile. However, the acrylic resin coating material has a heat resistance of 80 to 100 ° C., loses its flexibility after heat deterioration, and is limited in use in applications requiring heat resistance. On the other hand, silicone resin paints have excellent heat resistance,
The flexibility after heat deterioration was good, but the material cost was high, and there was a problem in workability because the paint crusted and gelled.
Further, the urethane resin coating described in JP-B-4-26354 has excellent heat resistance and workability, but has poor adhesion to metals such as copper and solder, and has a problem in reliability.

[0003]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art and is suitable for moisture-proof insulation and the like, and is capable of producing a heat-resistant moisture-proof insulation coating excellent in heat resistance and an insulation-treated electronic component. It provides the law.

[0004]

The present invention comprises (a) 100 parts by weight of hydroxyl group-containing polybutadiene, (b) 30 to 300 parts by weight of hydroxyl group-containing hydrogenated polybutadiene, and (c).
A polymer obtained by reacting polyisocyanate at a ratio such that the isocyanate group is in the range of 0.7 to 1.5 mol, relative to 1 mol of the hydroxyl group of the components (a) and (b),
The present invention relates to a heat-resistant and moisture-proof insulating coating containing 10 to 100 parts by weight of a tackifier and (e) a solvent, and a method for producing an insulating-processed electronic component by applying the coating to an electronic component and drying.

The (a) hydroxyl group-containing polybutadiene used in the present invention has a hydroxyl group in the molecule or at the terminal of the molecule,
From the flexibility and workability of the coating film, the number average molecular weight is preferably 300 to 1000, more preferably 500 to 50.
The range is 00. Examples of this commercial product include G-
1000, G-2000 (made by Nippon Soda Co., Ltd.) are mentioned.

The (b) hydroxyl group-containing hydrogenated polybutadiene used in the present invention has a hydroxyl group in the molecule or at the terminal of the molecule, and preferably has a hydrogenation rate of 9 from the flexibility of the coating film.
When it is 0% or more, the number average molecular weight is preferably in the range of 300 to 10,000, more preferably 500 to 5,000 in view of flexibility and workability of the coating film. Examples of this commercially available product include GI-2000 (manufactured by Nippon Soda Co., Ltd.).

The (c) polyisocyanate used in the present invention is tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate,
These trimethylolpropane adducts, pentaerythritol adducts, and the like are isocyanate compounds having two or more isocyanate groups in one molecule.

The tackifier (d) used in the present invention is
Examples thereof include hydrogenated rosin-based resins and alicyclic saturated hydrocarbon resins which are easily dissolved in a solvent and have a solid softening point at room temperature of preferably 50 to 180 ° C, more preferably 60 to 170 ° C.

The solvent (e) used in the present invention is a ketone solvent such as acetone or methyl ethyl ketone, toluene,
Examples thereof include aromatic solvents such as xylene, ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as ethyl alcohol and butyl alcohol, petroleum solvents such as mineral terpenes and naphtha.

The blending ratio of (a), (b) and (c) of the present invention is in the range of 30 to 300 parts by weight of the component (b) with respect to 100 parts by weight of the component (a). (B) component is 3
When the amount is less than 0 parts by weight, the flexibility of the coating film after heat deterioration is large, and when it exceeds 300 parts by weight, the drying property is deteriorated.
The polyisocyanate as the component (c) reacts with the components (a) and (b) at a ratio such that the isocyanate group is in the range of 0.7 to 1.5 mol with respect to 1 mol of the hydroxyl group as the components (a) and (b). Let When the isocyanate group exceeds 1.5 mol, the isocyanate group remains, which is not preferable from the viewpoint of stability of the coating material. When the isocyanate group is less than 0.7 mol, the molecular weight of the reaction product does not increase. (A),
The components (b) and (c) may be reacted at the same time, or the two components may be reacted first and then the other components.

(D) The amount of the adhesive finish compounded is (a),
With respect to 100 parts by weight of the reaction products of the components (b) and (c),
The range is 10 to 100 parts by weight. (D) component is 10
When it is less than 100 parts by weight, the adhesion is poor, and when it exceeds 100 parts by weight, the flexibility and moisture resistance of the coating film are deteriorated.

The blending amount of the solvent (e) is determined according to the viscosity of the coating composition which is related to workability, but is usually 20 to 80% by weight with respect to the heat resistant moistureproof insulating coating composition. In addition, fillers such as finely divided silicon oxide, magnesium oxide and calcium carbonate can be used in the coating material of the present invention. Further, in order to improve the drying property, manganese naphthenate, manganese octenoate, cobalt naphthenate, organic acid metal salts such as cobalt octenoate, tertiary butyl titanate, a reaction product of tertiary butyl titanate and ethyl acetoacetate, etc. Can be used.

Electronic components such as a microcomputer, a transistor, and a capacitor, which are insulated by using the heat-resistant and moisture-proof insulating paint according to the present invention, such as a mounting circuit board on which the components are mounted, are manufactured by a generally known method. Dipping method,
The paint may be applied to the electronic component by a brush coating method, a spray method, or the like and dried.

The present invention will be described below with reference to examples.
The present invention is not limited to these. Less than,
Those expressed as "parts" indicate parts by weight. Comparative Example 1 214 parts of butyl methacrylate and 25 parts of butyl acrylate
And 150 parts of toluene were added to a 1-liter four-necked flask, and the temperature was raised to 90 ° C. while maintaining the temperature while passing nitrogen gas. Polymerization was carried out while dropwise adding a solution in which 200 parts of butyl methacrylate, 21 parts of butyl acrylate, and 3 parts of azobisbutyronitrile were dissolved for 2 hours. afterwards,
After the temperature was raised to 110 ° C., the temperature was kept for 2 hours to complete the polymerization and then cooled, and when the temperature reached 50 ° C., 200 parts of toluene was added and stirred for 10 minutes to obtain a uniform solution varnish A.

Comparative Example 2 45 parts of trimethylolpropane, 174 parts of tolylene diisocyanate and 219 parts of butyl acetate were added to a 1 liter four-necked flask, and the mixture was stirred under a nitrogen gas atmosphere at 80 ° C.
And reacted for 2 hours. Then, a solution prepared by mixing and dissolving 281 parts of G-1000 (trade name of Nippon Soda Co., Ltd., hydroxyl group-containing polybutadiene, number average molecular weight 1400) and 281 parts of butyl acetate was added dropwise in about 1 hour, and then reacted at 80 ° C. for 2 hours. Varnish B was obtained.

Comparative Example 3 280 parts of GI-2000 (trade name of Nippon Soda Co., Ltd., hydroxylated hydrogenated polybutadiene, number average molecular weight 2100), 280 parts of xylene, and 280 parts of xylene in a 1 liter four-necked flask, the varnish obtained in Comparative Example 2 Mix 460 parts of B and stir at 70 ° C for 3
Allowed to react for hours. At this time, the number of moles of isocyanate groups was 1.1 moles per 1 mole of hydroxyl groups. Then, the synthesis temperature was lowered to 50 ° C., 100 parts of ethyl alcohol was added, and the mixture was reacted at 50 ° C. for 1 hour to obtain a varnish C.

Example 1 Varnish C obtained in Comparative Example 3 in a 1-liter four-necked flask
250 parts of hydrogenated rosin resin (softening point 80 ° C., trade name of Arakawa Chemical Industry Co., Ltd., ester gum HP) 40 parts and 210 parts of toluene were added and stirred at room temperature to obtain a uniform solution varnish D.

Example 2 Varnish C obtained in Comparative Example 3 in a 1-liter four-necked flask
250 parts, alicyclic saturated hydrocarbon resin (softening point 125
℃, trade name of Arakawa Chemical Industry Co., Ltd., Alcon P-125) 4
0 parts and 210 parts of toluene were added and stirred at room temperature to obtain a uniform solution varnish E.

The varnishes A to E obtained above were used as a tin plate (50 × 180 × 0.25) for pencil hardness and flexibility tests.
mm) and a copper plate (50 × 100 × 1.
6 mm) and dried at 80 ° C for 2 hours to 20 μm
A coating film of Then, this coating film was left in a constant temperature bath at 125 ° C., and the pencil hardness, the flexibility and the adhesion to copper were measured every time. The results are shown in Table 1.

[0020]

[Table 1]

[0021]

The coating film of the heat-resistant and moisture-proof insulating paint of the present invention is
Since the flexibility and the adhesiveness to a metal do not deteriorate even if it is deteriorated by heating at a high temperature, the heat resistance is excellent, and thus a highly reliable insulation-treated electronic component can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // C08G 18/62 NFC 18/69 NFC

Claims (3)

[Claims] 1. (a) Hydroxyl group-containing polybutadiene 100
Parts by weight, (b) hydroxyl group-containing hydrogenated polybutadiene 30
~ 300 parts by weight and (c) polyisocyanate,
Polymers obtained by reacting isocyanate groups in a ratio of 0.7 to 1.5 moles with respect to 1 mole of hydroxyl groups of components (a) and (b), and (d) tackifiers 10 to 1.
A heat-resistant and moisture-proof insulating coating material containing 00 parts by weight and (e) a solvent. 2. The heat-resistant moisture-proof insulating coating composition according to claim 1, wherein the tackifier has a softening point in the range of 50 to 180 ° C. 3. The heat-resistant and moisture-proof insulating paint according to claim 1,
A method of manufacturing electronic components that have been subjected to insulation treatment by applying to electronic components and drying.