JPH02189329A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in adhesive strength under shear and release adhesive strength by mixing a mixture of an epoxy resin with a rubber-modified epoxy resin with a specified curing agent. CONSTITUTION:100 pts.wt. mixture (A) comprising an epoxy resin (a) having an epoxy equivalent of 100-3500 and at least two epoxy groups on the average per molecule and a rubber-modified epoxy resin (b) obtained by reacting component (a) with a carboxylylated elastomer having an MW of 1000-5000 and 1.5-2.5 carboxyls on the average per molecule (e.g. carboxyl-terminated butadiene/ acrylonitrile copolymer rubber) and having a rubber component content of 5-20wt.% is mixed with a curing agent component (B) comprising 5-40 pts.wt. linear aliphatic diamine (c) of the formula (wherein n>=8) e.g. 1,12- diaminododecane) and optionally a curing agent (d) selected from among a dicyadiamide, an acid anhydride, a phenol, an acid hydrazide, a boron fluoride compound, an amineimide, and an amine adduct, and optionally a metallic powder (C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epoxy resin composition, and more particularly, to an epoxy resin composition that exhibits extremely excellent adhesive properties as a adhesive agent containing an epoxy resin as a main component. Regarding.

[Conventional technology]

Epoxy resin has electrical insulation, heat resistance, and corrosion resistance.

It has excellent properties such as adhesive properties, and can be used in various forms such as liquid, paste, sheet, and powder, so it is used in a variety of fields. In addition, various combinations are possible,
One of the reasons why it is widely used is that it is possible to change the properties of the cured product depending on the purpose of use.

However, such an excellent V? Even in the case of epoxy resins having adhesive properties, considerable internal stress is generated due to shrinkage during curing, which often prevents the epoxy resin from fully demonstrating its inherent physical properties. For example, in the case of adhesives, these internal stresses limit the adhesive strength that the adhesive develops; it prevents it from reaching its maximum adhesive strength. , -f: A large amount of filler fA is added to suppress the generation of the shrinkage f internal stress, but this cannot be said to be a perfect countermeasure. Mano epoxy resin has a shear adhesive strength of 20
It reaches 0 kg/c4 or more, but the peel adhesion strength is slightly
It weighs less than 2kg/25 rugs. Such a tough material.

It has the disadvantage that it easily breaks due to bending, impact, and fatigue, making it unsuitable as an adhesive for automotive applications that require toughness parameters such as bending, impact, fatigue strength, and peeling.

[Problem to be solved by the invention]

The problem to be solved by this invention is to develop an epoxy resin composition that suppresses the decline in inherent adhesive strength caused by the generation of internal stress and provides excellent adhesive properties by fully demonstrating adhesive ability. In other words, the method used to reduce the internal stress is to give epoxy resin 1COT flexibility.

These two effects combine to achieve both contradictory properties of high shear adhesive strength and high peel adhesive strength.

[Means for solving problems]

This problem is solved by using the general formula (A) HzN-+C as a curing agent in a conventional composition consisting of an epoxy resin and a curing agent.
Achieved by using a linear aliphatic diamine represented by Hz + NH2 (n total 8), and by using a rubber-modified epoxy resin obtained by reacting an epoxy resin and a carboxyl group-containing nidistomer as a resin component. be done.

That is, as a result of intensive studies by the present inventors in order to solve the above problems, we found that the epoxy resin, the linear aliphatic diamine represented by the above-mentioned shipman (A), and the epoxy resin completely reacted with the carboxyl foundation M elastomer. By using a rubber-modified epoxy resin that can be obtained by using a rubber-modified epoxy resin, it is possible to solve the drawbacks of the prior art described in 1. Heading.

The present invention has been accomplished.

The evoquine equivalent of the epoxy resin used in the present invention is 1
Normally, a number of about 100 to 3,500 is used.

An average of 2 or more epoxy groups in one molecule! Those that do so are preferably utilized. As such epoxy resin, bisphenol A type epoxy resin is suitable, but other types include bisphenol Ffi epoxy resin, cycloaliphatic epoxy resin, hydantoin epoxy resin, novolac type epoxy resin, and grindyl ester type epoxy resin'#
These can be used alone or in combination of two or more.

Further, as the epoxy resin used for the rubber-modified epoxy resin, the above-mentioned epoxy resins are used.

In addition, as the next rubber component used to modify the epoxy FILM ¥1, those that have been used conventionally have been used, and a typical example is carboxyl group-terminated butadiene-acrylonitrile copolymer rubber. Done,
This usually has a molecular weight of 1000 to 5000 and 1 molecule per ft.
t) The average value of VC is 1.5 because of the carboxyl group.
~2.5. Preferably, it is 1.8 to 2.4, and a straight-shaped one having a carboxyl group at the end of the molecular chain is preferable. The rubber-modified epoxy resin used in the present invention forms a sea-island structure after being cured by heating, and this rubber phase forms a V-3 during curing.
In other words, the rubber-modified Evo 4"4UIlr used is a rubbery polymer that reacts with the carbokyfur-based epoxy resin, so it reduces stress at the interface between the rubber phase and the epoxy resin phase. Because of the presence of bonds, the strength of the cured resin is maintained even if it becomes a two-phase system such as a sea-island structure. The resulting reduction in physical properties is unlikely to occur.The rubber component content in the present resin composition Vc and the mixture of the epoxy resin and the rubber-modified epoxy resin is preferably ri5 to 20@fi%.The rubber component content is lower than CO. When the value is lower, the cured product obtained from the composition of the present invention will not have a stress-relaxing effect due to the addition of the rubber component VC.

Also, if the rubber component content 4 becomes too high.

It is noted that the high #a ratio of the epoxy resin is impaired and the 7"L shear force is reduced.

However, the aliphatic diamine used as a curing agent component and rl are those shown by the above-mentioned - Funato (A),
Alkyl 'd4 length n of linear aliphatic diamine 7%8
Above, preferably n is 8 to 20. Furthermore, practical VC refers to compounds in which n is 8 to 12.

Specifically, 1, 8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1゜11-
One or more compounds selected from diaminoundecane and 1,12-diaminododecane are used in combination.

The aliphatic cyamine used in the present invention is:

Since the molecular chains between the functional groups (amine groups) are long (n total 8), the crosslinking density in the cured resin is low and the glass transition temperature is also low, making it possible to suppress curing shrinkage and the generation of internal stress. The amount of the aliphatic diamine added is 5 to 40 parts by weight, preferably 10 to 30 parts by weight, per 100 parts by weight of the epoxy resin.If this amount is not reached, the epoxy resin will not be sufficiently cured. However, if it exceeds 1&:, there will be a large number of unreacted functional groups, which may prevent a smooth crosslinking reaction.

In addition, these aliphatic diamines include diandiamide,
Acid anhydride type, phenol type, acid hydrazide type, boron fluoride compound type, amine imide type.

Even better effects can be obtained by using it in combination with at least one type of curing agent selected from the amine adduct type (hereinafter abbreviated as curing agent (2)). Practically, dicyanhydride is preferably used, in which case VC is used as a curing accelerator.
-(3,4'-diflorophenyl)-1,1-dimethylurine A, amine imide type.

It is preferable to use it by adding ft of amine adduct type curing agent or the like. The combined use with curing agent ■ is based on the reduction in cross-linking density that occurs when only aliphatic diamine is used.
The amount of aliphatic diamine and curing agent H to be added when curing agent (2) is used in combination.

It is also determined by the type of hardening agent used.
Usually, the aliphatic diamine is 10 to 30 parts by weight per part by weight of the epoxy resin. 3 to 20 parts by weight of the curing agent (2) are used.

Furthermore, the aliphatic diamine is solid at room temperature and has poor bath dissolution properties for epoxy resins; therefore, the epoxy resin composition of the present invention can be stored at room temperature. The composition of the present invention is most suitable for use as an adhesive composition.

When using this as an adhesive, apply it to the adherend,
After pasting these together, the edge of the blade is heat-cured and bonded.

Also, this adhesive is a metal powder used for the purpose of imparting conductivity to the adhesive so that it can be welded to the adherend by spot welding etc. Can be added. Suitable metal powder, C is copper,
Zinc, nickel, cadmium, stainless steel, aluminum, etc. can be mentioned, but preferably it is a powder selected from the group consisting of aluminum, zinc, nickel, and stainless steel powder. The amount of metal powder added must be 25% or more of the total amount of the epoxy resin adhesive in order to provide sufficient conductivity to the bath contact VC.

``17?1. Silica, clay, gypsum, calcium carbonate, barium sulfate in the epoxy resin composition of the present invention.

Fillers such as quartz powder, glass fiber, kaolin, mica, alumina, hydrated alumina, aluminum hydroxide, Merck, dolomite, zircon, titanium compounds, monopdenoid compounds, antimony compounds, pigments, anti-aging agents, -f: Other Additive components of the types commonly used in IC can be appropriately blended depending on the intended use and properties.

The composition of the present invention is obtained by adding the above-mentioned Evoquin resin, curing agent, and optional components as necessary, and then uniformly dispersing each component using a roll mixer, ball mill, etc., usually at room temperature.

[Practical Examples] The present invention will be specifically described below with reference to examples. Note that parts in the examples indicate parts by weight.

[Example 1] 50 parts of carboxyl group-containing acrylonitrile-butadiene copolymer rubber (number average molecular t: 3400, average carboxyl group: 1.9), carboxylic acid diglycidyl ester type epoxy resin ([320 to 360 per epoxy] 100 parts)
Triphenylphosphine 0.15 in a mixing pot
As a gk catalyst, a reaction was carried out at 150° C. for 4 hours to obtain a rubber-modified epoxy resin.

28 g of this rubber-modified epoxy resin j&'i'', bisphenol A type epoxy resin (epoxy equivalent: approximately 190).

72 parts of molecular weight 380), 18 parts of l,12-diaminododecane, 11 parts of alhanium powder, and 11 parts of submerged powder were kneaded for 1 hour at room temperature in a melt-resistant mixing pot, and then passed through three rolls to form an epoxy resin. All 4 compositions. Table 1 shows the properties of the cold-cured product obtained by heating and curing Evokin resin gold.

[Comparative Example 1] In place of 1,12-diaminododecane as a curing agent component, a BF'3/amine curing agent (activation temperature of about 120'
C) 12 parts? Example 1 and ICI except for blending using
The results for Mr. J are shown in Table 1.

[Comparative Example 2] The same procedure as in Example 1 was carried out except that 80 parts of an ethylenediamine-based curing agent (n=2 in formula (A) above) was used instead of 1,12-diaminododecane as the curing agent component. The results are shown in Table 1.

[Comparison 0:3] An amine imide curing agent (activation temperature 100 to 15 U''c) was used instead of l,12-diaminododecane as a curing agent component.
The procedure was carried out in the same manner as in Example 1, except that 18 parts of gold was added. The results are shown in Table 1.

[Comparison 9U4] Instead of 1,12-diaminododecane as a curing agent component, amine adduct curing agent (activation temperature 100°C or higher) 6
Table 1 VC shows the results obtained in the same manner as in Example 1 except that 1 part was used.

[Comparative Example 5] As a resin component, 0 parts of bisphenol A epoxy resin 1 () was added to the base V of the bisphenol A epoxy resin and the rubber modified epoxy resin. Table 41 shows results obtained in the same manner as in Example 1 except for using and blending.

[Example 2] The same procedure as in Example 1 was conducted except that 26 parts of the 1,12-diaminedodecane gold used in Example 1 was used. The results are shown in Table 1.

[Example 3] Instead of 1,12-diaminododecane in Example 1.

1.8 diaminooctane (in formula (A) above).

Table 1 shows the results obtained in the same manner as in Example 1 except that 18 parts (n-=8) were used.

[Example 4] As a curing agent component of Example 1, 18 parts of 1,12-cyamidoacuff was mixed with 6 parts of dicyandiamide.

V'i Example 1 was repeated except that 1 part of 3-(3,4-dichlorophenyl)-1,1-dimethylurea was used. The results are shown in Table 1.

In the margin below, however, the measurement methods for each physical property in Table 1 are as follows.

O gelation time: Measured at 150°C using a hot plate.

0 tensile shear contact crab According to JIS-6850, steel plate (SPCC-8D, IUOX25X1.6)
Measured at 20℃ using

OT Peelable Adhesive Crab According to JIS-6854, #I
Measured at 20°C using a plate (SPCC-81), 200 x 25 x 0.8 (shoulder depth).

〔Effect of the invention〕

As is clear from the Examples and Comparative Examples.

The epoxy resin composition of this invention provides high shear strength,
It is possible to obtain an epoxy resin composition that is compatible with high peelability #I.

Claims (4)

[Claims] (1) Epoxy resin, a rubber-modified epoxy resin obtained by reacting an epoxy resin with a carboxyl group-containing elastomer, a straight-chain fat represented by the general formula (A) with an alkyl chain length n of 8 or more as a curing agent component An epoxy resin composition containing a group diamine. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(n≧8) (A) (2) The epoxy resin composition according to claim 1, wherein the rubber component content in the mixture of the epoxy resin and the rubber-modified epoxy resin is 5 to 20% by weight. (3) As a curing agent component, at least one selected from dicyandiamide, acid anhydride type, phenol type, acid hydrazide type, fluoroboron compound type, amine imide type, and amine adduct type is used in combination. The epoxy resin composition according to 2. (4) The epoxy resin composition according to any one of claims 1 to 3, further comprising a metal powder.