JPH04130175A - Epoxy resin adhesive composition - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in bonding strength and undergoing no decrease in adhesive power with the progress of time by mixing an epoxy resin and a boron nitride powder at a specified weight ratio. CONSTITUTION:100 pts.wt. epoxy resin (e.g. bisphenol A epoxy resin) is mixed with 1-200 pts.wt. boron nitride powder to produce the title composition. This composition exhibits excellent adhesiveness even when at least one of adherends is a hardly bondable plastic comprising a polyarylene sulfide resin particularly, and it undergoes no decrease in adhesive power even when subjected to an endurance test such as thermal cycle test. It can be suitably used in the fields of the aircraft industry, automobile industry, household goods, sporting goods, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an epoxy resin adhesive composition. More specifically, the present invention relates to an epoxy resin adhesive composition that has particularly good adhesive properties when at least one of the adherends is a polyarylene sulfide resin (hereinafter referred to as PPS resin).

<Prior art> Epoxy resin adhesives are generally made by adding a certain hardening agent to an epoxy resin, mixing well, applying the mixture to various adherend materials, and allowing the two to react at room temperature or by heating.
It is cured and bonded.

Epoxy resin adhesives can bond a wide variety of materials with high strength, can be bonded sufficiently using only contact pressure (low-pressure curing), and have a small shrinkage rate because there are no by-products during reaction curing (low-shrinkage).
Cured epoxy resin also has excellent chemical resistance and electrical properties, making it suitable for a variety of adherends, including metals such as iron, steel, stainless steel, and aluminum, wood, concrete, various plastics, and glass. It is used as an adhesive for a wide range of materials, including ceramics.

Simply mixing a commercially available epoxy raw resin and a curing agent can produce an adhesive with acceptable performance for practical use to some extent, but in order to actually achieve a high level of performance, it is necessary to modify the epoxy resin and the curing agent. is also being considered.

In particular, in the case of adherends or plastics with poor adhesion properties such as PPS resin, the adhesive strength is low and it cannot be said that they can withstand sufficient practical use.

In order to overcome this drawback, PPS resin is subjected to low-frequency ultraviolet irradiation or special chemical surface treatments. There are many restrictions such as the need to adhere quickly, so it is difficult to say that it is practical.

On the other hand, efforts continue to be made to improve adhesive strength and other properties by adding inorganic fillers. That is, for example, the thermal expansion coefficient of epoxy resin is much larger than that of the adherend material, and therefore the adhesive layer is distorted due to curing shrinkage and thermal contraction, causing a decrease in adhesive strength. Inorganic fillers, such as silica, talc, alumina, zinc powder, mica, and asbestos, are used alone or in combination of two or more to be dispersed in resin compositions for the purpose of reducing curing shrinkage. It is also known to incorporate potassium titanate fiber (Japanese Patent Publication No. 63-51200).

<Problems to be Solved by the Invention> However, even if a conventionally known inorganic filler is blended, the adhesive strength is insufficient, particularly for PPS resin.

Therefore, the present inventors solved these drawbacks of epoxy resin adhesives and developed an adhesive with improved adhesion, especially an epoxy resin with excellent adhesion to PPS resin, which was conventionally considered to be a difficult-to-adhesive plastic. As a result of extensive research aimed at providing a resin-based adhesive, we have discovered that by using boron nitride as a filler, we have been able to create an adhesive composition that has improved adhesive strength to an extent that was previously unimaginable. We discovered that the adhesive strength and durability can be maintained and completed the present invention.

<Means for solving the problem> That is, the present invention provides that, for 100 parts by weight of epoxy resin,
This is an epoxy resin adhesive composition characterized by containing 1 to 200 parts by weight of boron nitride powder.

The epoxy resin used in the present invention has two
There is no particular restriction as long as it has 1 or more epoxy groups, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3,3'-diallyl bisphenol A diglycidyl ether, phenol novolak type epoxy resin, cresol novolac type epoxy resin. Epoxy resin, phloroglucinol triglycidyl ether, resorcin diglycidyl ether, tetraglycidyldiaminodiphenylmethane, triglycidylmethaminophenol, 1,5 naphthalenediol diglycidyl ether, 1゜6-naphthalenethiol diglycidyl ether, 3.3', 5.5'-tetramethyl-4,4
' -Biphenol diglycidyl ether, 4.4'
-Biphenol diglycidyl ether, neopentyl glycol diglycidyl ether, adipic acid diglycidyl ester, 0-phthalic acid diglycidyl ester, tris(4-hydroxyphenyl)methane triglycidyl ether, 1,3-bis[3-(o- Hydroxyphenyl)propyl] 1,1.3.3-tetramethyldisiloxane diglycidyl ether, 1.3-bis(3-hydroxypropyl) 1,1,3.3-tetramethyldisiloxane diglycidyl ether, linear Examples include aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, and halogenated epoxy resins.

Among these, those preferably used are epoxy resins that are liquid at room temperature or have a softening point of 100°C or less.

Most preferably, the formula: where n is the average degree of polymerization, is 0 or at most 15
A bisphenol A type epoxy resin having a positive integer of up to 100% is used.

The curing agent used in the present invention is not particularly limited as long as it is a curing agent for ordinary epoxy resins, and examples thereof include bisphenol A1 bisphenol F14.4'-dihydroxybiphenyl, 3,3'-diallylbisphenol A1 hydroquinone, Phenolic compounds such as rusinol, 1,2.4-1-lyhydroxybenzene, salicylic acid, phenolic novolak resin, Talezol novolak resin: 4,4'-diaminodiphenylsulfone,
4.4'-methylenebis(2-ethylaniline), 4.
Aromatic polyamines such as 4'-diaminodiphenylmethane, aliphatic polyamines such as diaminomaleonitonol and their derivatives, polyamide resin dimer acid polyamides, amine compounds such as amine imide compounds: phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride Acids, acid anhydrides such as trimellitic anhydride and pyromellitic anhydride, adipic acid dihydrazide, isophthalic acid dihydrazide, eicosanniic acid dihydrazide, 7.
Hydrazide compounds such as 11-octadecadiene-1,18-dicarbohydrazide and 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin Nidicyandiamide, addition reaction product consisting of epoxy and imidazole, boron trifluoride Examples include Lewis acid complex compounds such as complex compounds, metal chelate compounds, and the like.

Furthermore, in the present invention, among conventionally known curing accelerators, those having an action as a curing agent can also be used. Specific examples thereof include, for example, 2-methylimidazole,
2-ethyl-4methylimidazole, 2-phenyl-4
-methylimidazole, 2-phenyl-4-methyl5-
imidazole compounds such as hydroxymethylimidazole or acid addition salts thereof such as hydroxybenzoic acid,
Amine compounds such as N,N'-dimethylpiperazine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,40)undecene-7,4-dimethylaminopyridine, or hydroxybenzoin thereof Examples include acid or acid addition salts such as dihydroxybenzoic acid.

The amount of curing agent added to the composition of the invention is usually 0.1 to 200 parts by weight per 100 parts by weight of epoxy resin.

Other commonly used known curing accelerators may be added to the composition of the present invention, if necessary.

Examples of curing accelerators include, in addition to the compounds that can be included as curing agents mentioned above, triphenylphosphine, tricyclohexylphosphine, bis(diphenylphosphino)methane, tris(2,6-cymethoxyphenyl) ) Phosphine compounds such as phosphine; metal acetylacetonates such as aluminum acetylacetonate and cobalt acetylacetonate.

When adding the above-mentioned curing accelerator to the composition of the present invention,
Usually 0.1 to 20 parts by weight per 100 parts by weight of epoxy resin
0 parts by weight is added.

The boron nitride powder used in the present invention has the general formula 2B
It is a hexagonal network crystal with the chemical formula of N, and has a diameter of 0.8 to 5μ.
A powder with a particle size of s is desirable.

The boron nitride powder used in the present invention is, for example, [Azocapolone nitride GPJ (Denki Kagaku Kogyo ■)]
Those commercially available under the trade name can be used as they are.

The desired effects of the present invention can be achieved by blending the boron nitride powder in an amount of 1 to 200 parts by weight, preferably 5 to 120 parts by weight, per 100 parts by weight of the epoxy resin.

If the amount is less than 1 part by weight, the effect of improving adhesive strength will be poor, and if it exceeds 200 parts by weight, the viscosity of the uncured resin composition will increase significantly, making workability difficult, and the boron nitride It is uneconomical since the powder is relatively expensive.

Boron nitride powder can be used untreated or can be treated with conventional coupling agents such as epoxy silanes, amino silanes, acunol silanes, and titanate coupling agents. .

Fillers, rubber components, diluents, colorants, pigments, flame retardants, and the like are added to the oxidant of the present invention, if necessary.

Examples of fillers include, in addition to the boron nitride, aluminum oxide, magnesium oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, silica, quartz, kaolin, mica, asbestos, antimony trioxide, and the like.

Examples of the rubber component include, without particular limitation, silicone rubber, carboxyl group-containing butadiene nitrile rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, natural rubber, and the like.

Examples of diluents include the above-mentioned diluent containing one epoxy group in one molecule.
In addition to its own low viscosity reactive compounds, cellosolve, butyl cellosolve, butyl cellosolve acetate, carpitol, butyl carpitol, carpitol acetate, γ-butyrolactone, 4-valerolactone, propylene carbonate, xylene, toluene, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone, terpineol,
Examples include diacetyl alcohol, methyl alcohol, and benzyl alcohol.

Examples of colorants and pigments and flame retardants include titanium dioxide, yellow carbon black, iron black, molybdenum red, navy blue,
Examples include cadmium yellow, triphenyl phosphite, decabromodiphenyl ether, and hexabromobenzene.

The composition of the present invention may be mixed by melting at a high temperature as required, or by using a Banbury mixer, kneader roll, single or twin screw extruder, or mixer at a temperature of about room temperature to 150°C. A method of kneading using, etc. is applied.

The thus obtained epoxy resin adhesive composition is applied to the target adherend by coating, injection, spraying, etc. within the pot life of the resin adhesive composition to bond the resin. Adhesion can be achieved under the curing conditions of the agent composition, that is, by curing at room temperature or by heating.

<Example> Hereinafter, the present invention will be specifically explained with reference to Examples.

Examples 1 to 2 100 parts by weight of bisphenol A epoxy resin, 80 parts by weight of dimer acid polyamide and boron nitride powder were
They were mixed in the amounts shown in the table to prepare an adhesive composition.

This adhesive composition was applied to a molded plate of PPS resin (A 504, manufactured by Toshi ■) whose surface had been degreased with acetone, glued together, and cured at 80° C. for 1 hour.

The tensile shear adhesive strength of the obtained adhesive test piece was determined according to JIS K6.
850 at a tensile rate of +am/min. The results are shown in Table 1.

Comparative Example Co-12 An adhesive composition was obtained in the same manner as in Example 1, except that various fillers as shown in Table 1 were blended instead of boron nitride powder, and after curing, tensile shearing was performed. Adhesive strength was measured. The results are shown in Table 1.

Table 1*) Boron nitride powder Denkapolon nitride GP (Denki Kagaku Kogyo) Aluminum: A32 (Nippon Light Metal) Crushed silica:
FS44 (Denki Kagaku Kogyo) Spherical silica: FB44 (
Denki Kagaku Kogyo) Talli: PK (Fuji Talc) Mica A-31 (Yamaguchi Mica Kogyo) Calcium carbonate NN#200 (Nitto Powdered Chemicals) Glass fiber/MF-TIO (Central Glass) Calcium sulfate whisker Franklin fiber CA
-5 (Dainichiseika Industries) Potassium titanate whisker: T I 5M0D104
(Oita Chemical) Titanium oxide: Tybake R820 (Ishihara Sangyo) As is clear from Table 1, the boron nitride powder of the present invention was
It can be seen that the amount of adhesion to the PPS resin was significantly higher in the case where 00 parts by weight was added, compared to the case where no filler was added or the case where conventionally used fillers were used.

In addition, when observing the fractured surface of the test piece after measuring the adhesive strength,
Cohesive failure occurred in Examples 1 and 2, while interfacial failure occurred in Comparative Example 1. This also shows that the composition containing 50 to 100 wt % of boron nitride powder has extremely high performance.

Example 3 Using an adhesive composition prepared in the same manner as in Example 1,
PPS resin was applied to a molded plate of PPS resin (A504, Toshi ■) whose surface had been degreased with acetone and an aluminum plate (JIS H4000, thickness 2 mm) whose surface had been degreased with trichloroethane, and the PPS resin was applied in the same manner as in Examples 1 and 2. Adhesion test pieces between a plate and an aluminum plate were prepared.

The tensile shear adhesive strength of the obtained test piece and the heat cycle test (150°C, 30 minutes←-50°0130 minutes, 300
JIS K6850 tensile shear adhesive strength after cycle)
Measurements were made at a tensile speed of 1 cm/m.

The results are shown in Table 2.

As is clear from Table 2, those containing boron nitride powder have improved adhesion to aluminum plates compared to those containing no boron nitride powder. In addition, although the adhesive strength of those containing silica and titanium oxide improved to PPS resin and aluminum plates, heat cycle tests showed that the adhesive strength decreased, whereas those containing boron nitride powder showed improved adhesion to PPS resin and aluminum plates. No decrease in adhesive strength was observed in the heat cycle test, and the mode of failure was cohesive failure.

<Effects of the Invention> According to the present invention, an epoxy resin adhesive composition having extremely excellent adhesive strength can be obtained. In particular, even when at least one of the adherends is made of PPS resin, which is a difficult-to-adhesive plastic, it shows excellent adhesion, and the adhesive strength does not decrease even when subjected to durability tests such as heat cycle tests. Has excellent adhesive durability.

The epoxy resin adhesive of the present invention is widely used in various fields, such as the aircraft industry, the automobile industry, the optical machinery industry, the electrical equipment industry, railways, the vehicle industry, the ship industry, the civil engineering and construction industry, other industrial fields, and the home. It can be applied to supplies, sporting goods, etc.

Claims (2)

[Claims] (1) An epoxy resin adhesive composition characterized in that 1 to 200 parts by weight of boron nitride powder is blended with 100 parts by weight of epoxy resin. (2) The epoxy resin adhesive composition according to claim 1, wherein the epoxy resin adhesive is for polyarylene sulfide resin.