JPH0528725B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an epoxy resin composition, and more specifically, it has excellent flexibility and impact resistance, as well as pressurized moisture resistance (hereinafter referred to as PCT resistance), heat cycle resistance, and insulation properties. The present invention relates to an epoxy resin composition having excellent curing properties such as adhesiveness, electrolytic corrosion resistance, and solvent resistance. Conventional technologies and their problems Epoxy resins (1) have very little volume shrinkage because they do not generate volatile substances during curing, and (2) have strong adhesive strength to the material surfaces in contact with them during curing. It has excellent properties such as (3) excellent mechanical properties, (4) high resistance to chemicals, and (5) good electrical insulation, and is widely used in various fields. has been done. However, cured products of epoxy resins are inherently poor in flexibility and therefore have low impact resistance. Moreover, epoxy resins have the drawback of causing cracks, peeling, etc. when used for electronic parts in which various elements are embedded. Various studies have been made to improve the flexibility of cured epoxy resins.
% of epoxidized polybutadiene, which has excellent flexibility, has been proposed. In this case, a homogeneous mixture cannot be obtained due to poor compatibility between the general-purpose epoxy resin and epoxidized polybutadiene, and the epoxidized polybutadiene
Even when conventional curing agents such as acid anhydrides, amines, and imidazoles were added, curing did not occur, and therefore, sufficiently satisfactory curing properties could not be obtained. In addition, flexible epoxy resins that satisfy both PCT resistance and heat cycle resistance among curing properties are
Haven't gotten it yet. Means for Solving the Problems As a result of extensive research in view of the problems of the prior art described above, the present inventor has discovered epoxidized polybutadiene and a specific phenol resin that has never been used as a curing agent for epoxidized polybutadiene. By using epoxidized polybutadiene and pre-reacting the phenolic resin, it has (1) excellent flexibility and impact resistance, and (2) extremely excellent curing properties, especially flexible (3) Epoxy resin composition with excellent compatibility with other components such as curing accelerators, inorganic fillers, and flame retardants. They discovered that a product can be obtained and completed the present invention. That is, the present invention uses epoxidized polybutadiene 100
Epoxy containing a pre-reacted product with a viscosity of 15,000 to 80,000 cps obtained by reacting 2 to 60 parts by weight of a phenol novolak resin at 110 to 180°C for 0.5 to 5 hours, and 0.02 to 20 parts by weight of a curing accelerator. It relates to a resin composition. In the present invention, a pre-reactant obtained by pre-reacting epoxidized polybutadiene and a phenol novolak resin is used. Pre-reactants are usually
A predetermined amount of a mixture of epoxidized polybutadiene and solid phenol novolak resin having a viscosity of about 8000 to 50000 cps (30℃, using a B-type viscometer, model BH, the same applies hereinafter) is heated at 110 to 180℃. 0.5～
The reaction was carried out for 5 hours to form a melt having a viscosity of 15,000 to 80,000 cps. If the above-mentioned preliminary reaction is not carried out, disadvantages such as crystal precipitation, generation of uncured parts, and deterioration of cured physical properties occur, which is not preferable. Any known epoxidized polybutadiene having a number average molecular weight of about 500 to 25,000 can be used, such as 1,2-polybutadiene, 1,4-polybutadiene, polyisoprene, polychloroprene, butadiene-isoprene copolymer, butadiene-styrene. Examples include epoxidized copolymers, butadiene-2-ethylhexyl acrylate copolymers, butadiene-n-octadecyl acrylate copolymers, and the like.
Any known method can be used to epoxidize these compounds. Any known phenol novolak resin can be used, such as phenol novolak resin, tert-butylphenol novolak resin, nonylphenol novolak resin, polyparaphenol novolak resin, and alkyl-modified phenol novolak resin. etc. can be mentioned. The blending amount of the phenol novolak resin is approximately 2 to 60 parts by weight per 100 parts by weight of the epoxidized polybutadiene. Outside this range, uncured portions will occur and the cured physical properties will deteriorate. As the curing accelerator, known ones can be used,
For example, tertiary amines, triazoles, imidazoles, etc. can be mentioned. Specific examples include benzyldimethylamine, triethanolamine, dimethylaminomethylphenol, tris(dimethylaminomethyl)phenol, triethyltetramine, 3,9-bis(3-
Tertiary amines such as aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, triazoles such as 1,2,3-benzotriazole and 5-methyltriazole, 2-phenyl Imidazole, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2
-undecylimidazole, 2-peptadecylimidazole, 1-vinyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methylimidazole, 2-isopropylimidazole, 1-cyanomethyl -2-methylimidazole, 2-[β
-(2'-methylimidazole-(1)')]-ethyl-
4,6-diamino-s-polyazine-isocyanurate, 1-aminoethyl-2-methylimidazole, 4,4'-methylene-bis-(2-ethyl-
5-methylimidazole), 2-phenyl-4-
Examples include imidazoles such as benzyl-5-hydroxymethylimidazole, reaction products between 2-methylimidazole and phenol novolak resin, and reaction products between tris(dimethylaminomethyl)phenol and bisphenol A type epoxy resin. be able to. The amount of curing accelerator is
Normally per 100 parts by weight of epoxidized polybutadiene
The amount is about 0.02 to 20 parts by weight, preferably about 0.05 to 10 parts by weight. If it is less than 0.02 part by weight, curing time becomes slow or uncured portions occur, resulting in poor cured physical properties. On the other hand, if it exceeds 20 parts by weight, uncured portions may occur, resulting in a decrease in physical properties. The epoxy resin composition of the present invention may contain, as necessary, inorganic fillers, flame retardants, colorants, coupling agents and mold release agents to improve the compatibility between the above additives and the epoxy resin. Additives used in the above may also be added. As the inorganic filler, any commonly used in this field can be used, such as fused silica,
Crystalline silica, spherical silica, glass fiber, glass powder, talc, clay, mica, alumina,
Examples include aluminum hydroxide, aluminum silicate, zirconium silicate, silicon nitride, calcium carbonate, magnesium carbonate, barium sulfate, and calcium hydrogen phosphate. In addition, the composition of the present invention
When used in ICs, etc., as an inorganic filler,
Ordinary low radiation substances such as low α-ray silica and low α-ray alumina may be added. The particle size of the inorganic filler is not particularly limited and may be selected as appropriate, but it is usually 2.
The thickness may be approximately 100μ. The amount of the inorganic filler to be blended is not particularly limited, but it is usually about 2 to 400 parts by weight per 100 parts by weight of epoxidized polybutadiene. Any flame retardants commonly used in this field can be used, such as hexabromobenzene, decabromobenzene, antimony trioxide,
Examples include tetrabromobisphenol A, hexabromobiphenyl, decachlorobiphenyl, red phosphorus, surface-treated red phosphorus, and hydrated alumina. The amount of flame retardant is not particularly limited, but it is usually 2 to 100 parts by weight of epoxidized polybutadiene.
The amount may be about 400 parts by weight. As the coloring agent, common ones can be used, and examples thereof include carbon black, iron oxide, titanium oxide, fluorocyanine blue, and phthalocyanine green. The amount of colorant added is not particularly limited, but it is usually epoxidized polybutadiene.
The amount may be about 1 to 50 parts by weight per 100 parts by weight. As the coupling agent, common ones can be used, and examples thereof include epoxysilane-based, aminosilane-based, and titanium-based coupling agents. The amount of the coupling agent to be blended is not particularly limited, but the amount of the coloring agent may generally be about 0.1 to 5 parts by weight per 100 parts by weight of the epoxidized polybutadiene. As the mold release agent, common ones can be used, such as natural waxes, synthetic waxes, and the like. The amount of the mold release agent to be blended is not particularly limited, but it may generally be about 0.1 to 10 parts by weight per 100 parts by weight of epoxidized polybutadiene. The epoxy resin composition of the present invention is produced by mixing predetermined amounts of each of the above components in accordance with a conventional method. In using the epoxy resin composition of the present invention, any conventional method can be employed, such as dipping method, casting method, drop coating (chip-on-board) method, impregnation method, injection method, transfer molding method. , compression molding method, printing method, etc. At this time, the curing conditions of the composition of the present invention are not particularly limited, but for example, in the dipping method and impregnation method, the curing conditions are as follows. In the drop coating method and the drop coating method, the heating time may be about 1 to 2 hours at about 130 to 150°C. The epoxy resin composition of the present invention is suitable for use in diodes, transistors, ICs, LSIs, VLSIs, SVLSIs, optical semiconductors, compound semiconductors, card ICs, and hybrids.
Materials for direct encapsulation of semiconductors such as ICs, paper, metallized paper,
Film, ceramics, electrolytic mica, tantalum, glass, printed capacitors, windings, films, SiC, carbon, varistors, semiconductors, borocarbon, glaze, ceramic resistors, chiyoke coils, inductance coils, magnetic heads, relays , transformers such as low frequency transformers, pulse transformers, power transformers, flyback transformers, coils, connectors, plazas, jacks, sockets, switches, wiring boards, electronic parts such as printed circuit board circuits, etc. Regular use of epoxy resin Can be used for any of the following purposes. Effects of the Invention In the present invention, for the first time, we succeeded in developing a flexible epoxy resin composition that can simultaneously satisfy both PCT resistance and heat cycle resistance. The epoxy resin composition of the present invention has excellent flexibility and impact resistance,
In addition, due to the excellent compatibility between the components, it has extremely good curing properties (PCT resistance, heat cycle resistance, insulation properties, adhesive properties, low stress properties, electrical corrosion resistance, solvent resistance, etc.) . Examples Examples and comparative examples are given below to further clarify the present invention. Examples 1 to 3 Each raw material was mixed in the proportions (parts by weight) shown in Table 1 to obtain an epoxy resin composition of the present invention. The preliminary reaction between the epoxidized polybutadiene and the phenol novolac resin was carried out at 110°C for 3 hours.
The viscosity of the pre-reactant was 35000 cps.

[Performance test method]

(1) Insulation A comb-shaped electrode with a line width and line spacing of 300 μm is printed on a ceramic board (31 x 16 x 1 mm) using silver paste, a lead wire is attached, and an epoxy resin composition is applied to the entire surface to a thickness of 1.0 mm. The test piece was then cured at 100°C for 1 hour + 150°C for 1 hour. Using this test piece, insulation properties were measured according to JIS-C-5102. (2) PCT resistance The same test piece as in (1) was heated at 130℃, 2.4 atm, 85%
After being placed under RH conditions for 100 hours, the insulation properties of the specimens were measured. (3) Heat cycle resistance The epoxy resin composition was cast to a thickness of 1 mm into a silicone mold with a diameter of 30 mm and a depth of 10 mm, and cured. A degreased spring washer (SUS material) was placed on top of it, and an epoxy resin composition was cast onto it to a thickness of 10 mm and cured. After curing, it was removed from the silicone mold and used as a test piece. After 100 cycles of leaving this test piece in a thermostat at -55°C and +125°C for 1 hour each, the number of cracks was determined. (4) Solvent resistance The same test piece as in (1) was mixed with acetone, toluene,
After being immersed in Trichloride and Freon for 24 hours, the appearance, gloss, hardness, etc. of the test pieces were observed and judged based on the following criteria. In addition, as a Freon, Freon
TE (manufactured by Mitsui Fluorochemicals) and Daiflon Solvent S3-E (manufactured by Daikin Industries) were used. 〇……No change×……Deterioration in appearance, gloss, hardness, etc. (5) Using the flame retardant epoxy resin composition, a test piece of 12.7 x 127 x 1.6 mm was prepared and UV-
Tested in accordance with Law 94. The judgment criteria are as follows. V-O...Does not burn x...Burns (6) Electrolytic corrosion After coating an epoxy resin composition to a thickness of 1.0 mm on a ceramic substrate (40 x 100 x 0.6 mm) and curing it, A silver paste was printed on top and dried to form a test piece. This test piece was heated at 40℃.
Apply 90V (DC) in a constant temperature and humidity chamber at 90%RH,
After 500 hours, the condition of the coating film was examined under a microscope (100~
200 times) to examine the state of silver migration. The judgment criteria are as follows. 〇...Silver migration does not occur x...Silver migration occurs Comparative examples 1, 2 Each raw material was blended in the proportions (parts by weight) shown in Table 2 to obtain a conventional epoxy resin composition. Ta. The obtained epoxy resin was subjected to the same performance test as in the example. The results are shown in Table 3.

[Table] Comparative Example 3 A flexible silicone resin (Toray Silicone No. 3251), which is used for the same purpose as the epoxy resin of the present application, was subjected to the same performance test as in the example. The results are shown in Table 3. Comparative Example 4 An epoxy resin composition was obtained in the same manner as in Example 2 except that the preliminary reaction was not performed. The obtained epoxy resin was subjected to the same performance test as in the example. The results are shown in Table 3.

[Table] From Table 3, it can be seen that the epoxy resin composition of the present invention has excellent curing performance in various types, has performance equivalent to that of flexible silicone resin, and is superior in solvent resistance. . Examples 4-5 and Comparative Examples 5-6 Except for changing the reaction time in the preliminary reaction,
In the same manner as in Example 1, the viscosity was 13000 cps,
Preliminary reactants of 18,000 cps, 60,000 cps, and 85,000 cps were obtained, and epoxy resin compositions were prepared using these. The obtained epoxy resin composition was subjected to various performance tests. Regarding insulation, PCT resistance, heat cycle resistance, solvent resistance, flame retardance and electrolytic corrosion resistance,
The test was conducted in the same manner as in Example 1. Other test methods are as follows. The results are shown in Table 4. *Mixability Using a stirrer or a mixer, it was tested to see if it could be mixed uniformly. The judgment criteria are as follows. 〇... Can be mixed uniformly. ×...Unable to mix uniformly. *Coating film properties (dipping method) A 30 x 15 x 5 mm polyester film capacitor (ordinary Mylar capacitor) was immersed in the epoxy resin composition, pulled up and cured. 〇...The film thickness became uniform. ×...The thickness was not constant and was non-uniform. *Dischargeability (Drop coat method) A 50 μm dispenser-specific syringe (manufactured by Iwashita Engineering Co., Ltd.) containing the epoxy resin composition was subjected to a discharge test using a dispenser dispensing machine. The discharge conditions are air pressure 2.0Kg/cm ² ,
The needle diameter was 1.1 mm (inner diameter of the needle), and the ejection time was 2 seconds. 〇...A discharged product of a constant weight was obtained. ×...The weight is not constant each time the product is discharged, or the discharge pressure becomes high, which is inconvenient for discharge. *Impregnation property A PP test tube (inner diameter 11 mm, length 120 mm) was filled with 5 ± 0.1 g of glass powder (manufactured by Toshiba Baronity, GB-732, particle size 63-105 μm) without any gaps, and then placed in a vacuum device. A fixed weight of the epoxy resin composition was injected from the top of the chamber. The degree of vacuum was 15±3 mmHg. This was taken out from the vacuum apparatus and cured, and the part containing the glass powder was cut with a cutter knife, and the unimpregnated glass powder was taken out and the degree of impregnation was examined. 〇……70% or more impregnated. ×...The impregnation rate is less than 70%. *Shape retention A circle with a diameter of 5 mm was drawn on a ceramic substrate, and 20±0.1 mg of the epoxy resin composition was placed inside the circle so as not to protrude from the circle. This was cured, and the diameter of the cured resin was measured. 〇……5～5.5mm ×……5.5mm or more

【table】

【table】

Claims (1)

[Claims] 1 100 parts by weight of epoxidized polybutadiene and 2 to 60 parts by weight of phenol novolak resin in 110 to 180 parts by weight
Viscosity 15000~ obtained by reacting at ℃ for 0.5~5 hours
80000cps pre-reactant and curing accelerator 0.02~20
An epoxy resin composition containing parts by weight.