JPH01278592A - Epoxy resin based adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having tensile shear strength, especially having excellent adhesion of steel with a fiber reinforced plastics, by blending an epoxy compound component with the reaction product of a diene based liquid rubber with an aliphatic polyamine and polyamide resin based curing agent. CONSTITUTION:The aimed composition consisting of (A) an epoxy compound component [containing <=35wt.% diene based liquid rubber] containing an epoxy resin compound modified with a diene based liquid rubber having terminal carboxyl groups and 1,000-7,000 molecular weight, (B) a product obtained by reacting (i) an aliphatic polyamine compound expressed by the formula (n is 2-5) with (ii) a diene based liquid rubber having terminal carboxyl groups and 1,000-7,000 molecular weight at a molar ratio of component i: component ii of 5-100 and (C) polyamide resin based curing agent, used at an amount not less than an active hydrogen amount contained in the components B and C equal to epoxy group numbers in the component A and having component B being in the range of 10-90% among total amounts of the components B and C.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an epoxy resin adhesive composition. More specifically, the present invention relates to an epoxy resin adhesive composition useful for bonding dissimilar materials, particularly steel and fiber reinforced plastics.

[Background of the Invention] Structural adhesives are used in a wide range of industrial fields such as aerospace, vehicles, ships, architecture, civil engineering, electricity, and electronics.

In recent years, instead of the structural members such as steel plates and aluminum that have traditionally been used in these fields,
With weight reduction as the goal, sheet molding compounds and rainbowst reactive injectors [SMC and R
The use of plastics, including fiber-reinforced plastics (FRP) called -RIM, etc., is being studied or put into practical use. Kowara's old fee is [)
``In writing applications, they are often used under harsh conditions, and they are often used to bond not only glass materials together, but also dissimilar materials and plastics. The performance that corresponds to that is also required.

As an improved epoxy resin adhesive for the above-mentioned plastic materials, for example, a reaction product of a diene liquid rubber and an aliphatic polyamine is used as a curing agent, and a diene rubber and an epoxy compound are used in the base epoxy resin. The present applicant has already filed a patent application for this adhesive (see Japanese Unexamined Patent Publication No. 62-236879).

The above-mentioned epoxy resin adhesive composition has excellent tensile shear strength and peel strength in the temperature range from low 7 to around 100°C when adhering the plastic materials, especially SMC. ing.

However, when the above-mentioned epoxy resin adhesive composition is used to bond steel and SMC, when the adherend is returned to room temperature after the epoxy resin is cured by heating or after being placed in a high temperature environment, Is there a problem with interfacial peeling or raw greens?

On the other hand, when using an epoxy resin adhesive to bond materials with a large difference in coefficient of thermal expansion, such as steel and plastic materials, use a stiffening agent such as a polyamide resin hardener as a hardening agent. Compounds are known to be used to reduce stress during contraction. However, if the curing agent in the adhesive composition disclosed in JP-A-62-236879 was simply replaced with a polyamide resin curing agent, sufficient adhesion to plastic materials such as SMC could not be obtained. I can't.

[Mo 1 of the Invention] The main objective of the present invention is to provide an epoxy resin adhesive composition suitable for adhesion between dissimilar materials.

The present invention has excellent tensile shear strength even at relatively high temperatures, especially when adhering steel and fiber-reinforced plastic deck.
We present an epoxy resin adhesive composition that
1 target.

[Summary of the Invention] According to the study of the present inventor,
In the epoxy resin adhesive composition disclosed in Publication No. 9, by using a reaction product of a diene liquid rubber and an aliphatic polyamine as a curing agent together with a polyamide resin curing agent in a specific ratio. It has been found that good adhesion can be obtained between different materials, especially between steel and fiber-reinforced plastic.

That is, the present invention provides component A with a molecular weight of 1000 and having a carboxyl group at its two ends.
Epoxy compound component containing at least one type of epoxy compound modified with diene liquid rubber of ~7000 (however, the amount of diene liquid rubber component in the epoxy compound component is within 35% by weight): Component B General formula H2N (C2H4NH), an aliphatic polyamine compound having H (where n is an integer of 2 to 5) and a molecular weight of 100 having a carboxyl group at the end.
0 to 7000, and the molar ratio of the aliphatic polyamine compound to the diene liquid rubber is 5 to 10.
0 product reacted in the range of The total number of active hydrogens contained in component A is equal to or greater than the number of epoxy groups contained in component A, and B of the total amount of component B and component C is
An epoxy resin adhesive composition characterized in that the components are present in amounts ranging from 10 to 90% by weight.

Preferred embodiments of the epoxy resin adhesive composition of the present invention are as follows.

(1) The amount of diene liquid rubber component in component A is 5 to 30
Must be within the weight% range.

(2) Component A must contain an unmodified epoxy compound.

(3) A product consisting of an aliphatic polyamine compound and a diene-based liquid rubber component in component B, or a molar ratio of the aliphatic polyamine compound to the diene-based liquid rubber component of 10 to 30.
The product must be reacted in an amount within the range of .

(4) The total amount of diene liquid rubber components contained in component A and component B, or 015 to 0 relative to the total amount of component A and component B.
Must be within the range of 40%.

(5) A silane coupling agent having an amino group and/or an SH group must be contained within 5% by weight based on the total amount of the adhesive composition.

(6) A silane coupling agent containing an epoxy group must be contained in an amount within 5% by weight based on the total amount of the adhesive composition.

[Effects of the Invention] The epoxy resin adhesive composition of the present invention contains a diene liquid rubber and an aliphatic polyamine as a curing agent in an epoxy compound component containing at least one type of epoxy compound modified with a diene liquid rubber as a main ingredient. By using the reaction product of and a polyamide resin curing agent in a specific ratio,
When adhering different materials, especially steel and SMC, it is possible to obtain excellent adhesion that cannot be obtained when each of the above two types of curing agents is used alone.

Furthermore, the epoxy resin adhesive composition of the present invention can bond steel and SMC by a simple process such as degreasing the surface of a steel plate without performing complicated surface treatment, and this bonding is relatively effective. Shows excellent tensile shear strength up to high temperature ranges.

[Detailed Description of the Invention] Component A blended into the adhesive composition of the present invention is an epoxy compound component containing at least one epoxy compound modified with a diene liquid rubber having a molecular i of 11000 to 7000 and having a carboxyl group at the end. It is. However, the amount of diene liquid rubber component in the epoxy compound component is 35% by weight.
Within

This component A may consist only of the above-mentioned modified epoxy compound, or may be a mixture of the above-mentioned modified epoxy compound and unmodified epoxy compound.

As the unmodified epoxy compound or the epoxy compound to be modified, an epoxy compound having an average of two or more epoxy groups in one molecule, which is used as a component of ordinary epoxy resin adhesives, is used. Examples of such epoxy compounds include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, novolac-type epoxy resins, polyfunctional phenol-type epoxy resins, chrysylamine-type polyfunctional epoxy resins, and various helokenized epoxy resins. Examples include resins.

In addition, the reaction between resorcinol and shrimp halohydrin 1
% cyclicyl ether compounds, glycidyl ester type epoxy resins, polyglycol type epoxy resins,
Cycloaliphatic epoxy resins, hydantoin type epoxy resins, etc. can also be used. Epoxy compounds can be used alone or in combination of two or more.

Examples of diene-based liquid rubbers having a carboxyl group at the end that are used to modify epoxy compounds include carboxyl group-terminated acrylonitrile butadiene rubber, polybutadiene rubber, polyisoprene rubber, polychloroprene rubber, etc., and their molecular weight Examples include liquid rubbers having a molecular weight of about 1,000 to 7,000. Particularly preferred are acrylonitrile butadiene rubber and polybutadiene rubber. Typical products include Hycar CTBN 1300x8, Hycar
CTBN 1300X13, Hycar CT
B 2000x162 (all manufactured by BF Gutdridge), Nl5SOPB C-1000, Nl5SOPB C-2000 (all manufactured by Shiraki Soda ■), Po1y bd R-45MA (manufactured by Idemitsu Petrochemical ■), etc. can.

The amount of diene liquid rubber contained in component A is within 35% by weight. If the diene liquid rubber exceeds 35% by weight, the peel strength and tensile shear strength at high temperatures will deteriorate. Furthermore, A
The diene liquid rubber contained in the components is preferably within 30% by weight, and preferably 5% by weight or more. However, if the diene liquid rubber is used in an amount of 10% by weight or more, the effect of its addition becomes even more effective.

The reaction between the epoxy compound and the carboxyl group-terminated diene liquid rubber is usually carried out at a temperature of 80 to 200"C (preferably 100 to 200"C).
170°C).

Next, component B is an aliphatic polyamine compound having the formula: % formula %) (where n is an integer of 2 to 5), and a diene liquid rubber having a molecular weight of 1000 to 7000 and having a carboxyl group at the terminal. It is a product obtained by reacting the aliphatic polyamine compound to the diene liquid rubber at a molar ratio of 5 to 100 (preferably 10 or more and 30 or more).

Examples of the above aliphatic polyamine compounds include dielenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexazine, and the like. Particularly preferred are triethylenetetramine and tetraethylenepentamine.

Examples of diene-based liquid rubbers having a carboxyl group at the end used in the preparation of the reaction product described above as component B include the diene liquid rubber having a carboxyl group at the end used in the preparation of the modified epoxy compound of the component A. Examples include those similar to diene liquid rubber. However, it is not necessary that the diene liquid rubber is the same as the diene liquid rubber used for preparing the modified epoxy compound of component A.

The molar ratio of the polyamine to the diene liquid rubber is 5.
Must be in the range of ~100, especially J-13 above 10
It is preferably 0 or less. If this molar ratio is less than 5, the reaction product will be in a gel state and its compatibility with the epoxy compound will decrease. On the other hand, when the molar ratio exceeds 100, there is too much free aliphatic polyamine, and the cured product has a high crosslinking density and poor flexibility, so that sufficient improvement in peel strength cannot be expected.

The reaction between the aliphatic polyamine and the carboxyl group-terminated diene liquid rubber is usually carried out at 110 to 200°C (preferably at 13°C).
(0 to 180°C).

The epoxy resin adhesive composition of the present invention is characterized by containing a polyamide resin curing agent as component C in a specific proportion together with the above-mentioned components A and B. When bonding dissimilar materials with large differences in coefficient of thermal expansion using epoxy resin, stress during shrinkage can be reduced by using a compound with stiffness, such as a polyamide resin curing agent, as a curing agent. has been known for a long time. The polyamide resin curing agent of component C is preferably a conventionally known polyamide resin curing agent used for the above-mentioned purpose. Typical products include Persamide 115, Persamide 125, and Persamide 140 (all of the following -1-1 are manufactured by Daiichi Seneral ■).

Note: The blending ratio of component B and component C needs to be determined so that the amount of component B is in the range of 10 to 90% by weight out of the total amount of component B and component C. ~70
It is preferable to set the amount within a range of % by weight.

If the amount of component B is less than 10% by weight, the tensile shear strength in a relatively high temperature range will decrease, and if it is more than 90% by weight, the stress during shrinkage when adhering to steel will increase, resulting in peeling at the interface. tends to occur more easily. Furthermore, since persamide 115 and persamide 125 have insufficient heat resistance, when their blending ratio increases, the tensile shear strength in a relatively high temperature range may decrease. Therefore, the blending ratio of component B and component C and the polyamide resin curing agent used for component C are preferably selected in consideration of the operating temperature range of the adhesive composition of the present invention.

The epoxy resin adhesive of the present invention may contain a silane coupling agent, and the adhesion is further improved by incorporating the silane coupling agent.

The silane coupling agent can be incorporated into the adhesive composition by adding it to component A (epoxy compound component), component B, or component C (curing agent component).

When a silane coupling agent is added to component A and blended, it is preferable to use a silane coupling agent having an epoxy group in the molecule.
, 4-epoxycyclohexyl)ethyltrimethoxysilane, γ-crisitoxypropyltrimethoxysilane,
Examples include γ-crisidoxypropyldiethoxysilane.

When adding and blending a silane coupling agent to component B or component C, amino groups and/or SH
It is preferable to use a group silane coupling agent, examples of which include γ-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminethyl)-γ-
Examples include aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, propyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

Note that the silane coupling agent can also be independently blended into the adhesive composition.

In the adhesive composition of the present invention, component B and C
The blending amount of the component must be an amount that makes the total number of active hydrogens contained in the B component and the C component equal to the number of epoxy groups contained in the A component (stoichiometric equivalent) or more, It is desirable that the amount is 1.5 times or less of the above stoichiometric equivalent.

The total amount of the diene liquid rubber component contained in the A component and the B component is 0.15 to 0.0% relative to the total amount of the A component and the B component.
Preferably in the range of 4% by weight, 0.2 to 0.3
A range of % by weight is particularly preferred. If the amount of diene liquid rubber is too small, the cured product of the epoxy resin composition tends to become too hard, making it difficult to obtain sufficient peel strength. Furthermore, if the amount of diene liquid rubber is too large, the heat resistance tends to be insufficient, and the tensile shear strength and peel strength at high temperatures tend to be low.

The adhesive composition of the present invention can be cured at room temperature, but in order to more reliably obtain high-strength adhesion, it is necessary to cure the adhesive composition at room temperature.
It is desirable to heat cure at 0 to 200°C, preferably 70 to 140°C. Further, the curing does not necessarily have to be carried out in one step, but a two or more step curing operation such as pre-curing at a low temperature and then curing at a higher temperature may be used.

The adhesive composition of the present invention includes metal oxides such as titanium dioxide and alumina, silicates, talc, calcium carbonate,
Known fillers or reinforcing agents such as clay, metal powder, glass fiber, carbon fiber, polyamide fiber, coloring agents such as pigments and dyes, flame retardants, leveling agents, etc. can be added at any stage before curing depending on the purpose of use. can be added.

In addition, component A (epoxy compound), component B (curing agent),
Mixing of component C (hardening agent) and addition of various additives can be carried out using various mixing devices. Examples of mixing devices used for such purposes include rolls, kneaders, extruders, etc. -ter, etc.

Next, Examples and Comparative Examples of the present invention will be shown.

The tensile shear strength on each side was determined by the following method.

'3JU-・Cut-1-Method length 100mm, width 25mm, thickness 1.6mm steel (S
PCC-SD) and SMC (SMC, class A, manufactured by Takeda Pharmaceutical Company Limited) with a length of 100 mm, width of 25 mm, and thickness of 3 mm were used as test pieces, and both ends of each test piece were measured with a length of 12.5 mm and a width of 3 mm. 25mm, adhesive thickness 0.5mm
After curing at 80° C. for 60 minutes, measurement was performed at a tensile speed of 5 mm and 7 minutes in accordance with JIS-6850.

The modified epoxy resins used on each side and the reaction products of diene liquid rubber and aliphatic polyamine are as follows. Note that "part" and "1%" mean "part by weight" and "wt% J, respectively, unless otherwise specified.

HycarCTBN 13
00x8 (Carboxyl group equivalent weight 1850 g/e
q, molecular weight 3400) 100 parts and Epicote 82
500 parts of bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy ■, epoxy equivalent: 188 g/eq, were charged and stirred at 150° C. for 2 hours under a nitrogen atmosphere to obtain a yellowish brown homogeneous liquid. The content of diene liquid rubber component is 1
It was 67%.

Add the diene resin rubber and 1-polyamine to the oxidation stirrer, nitrogen gas inlet tube, thermometer, and cooling tube (1 digit, 1 flask with 1 HycarCTBN).
300X8 (Carboxyl group equivalent: 1850 g/
710 parts of tetraethylenebentamine was added to 100 parts of eq, molecular weight 3400) and stirred for 1 hour at 180°C in a nitrogen atmosphere to obtain a pale yellow homogeneous liquid. The resulting liquid had a viscosity of 500 poise when measured at an amine equivalent of 135.25°C.

[Example 1] Component A consisting of 50 parts of Epikote 828 and 50 parts of modified epoxy resin was added with 40 parts of the reaction product of the diene liquid rubber and aliphatic polyamine (component B) described in -, and
An adhesive was prepared by mixing 14 parts of Persamide 115 (component C; manufactured by Daiichi General ■, amine value 238). The above amine value is a value obtained by measuring the number of KOHO mg corresponding to amine alkalinity present in 1 g of sample by potentiometric titration. The total amount of component B and component C in -1- is the stoichiometric equivalent to the epoxy group contained in 100 parts of component A.

Using this adhesive, a test piece was created by the method described above,
At temperatures of 23° C. and 80° C., the tensile shear strength was measured by the method of Koren and the adhesion was evaluated.

The adhesive evaluation results are shown in Table 1.

[Example 2] An adhesive was prepared in the same manner as in Example 1, except that the curing agent was 30 parts of component B and 28 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 1.

The adhesive evaluation results are shown in Table 1.

[Comparative Example 1] An adhesive was prepared in the same manner as in Example 1 except that only 50 parts of component B was used as the curing agent and component C was not used at all. A test piece was prepared using this adhesive according to the method described above, and the adhesiveness was evaluated in the same manner as in Example 1.

[Comparative Example 2] Only 70 parts of component C (persamide 115) was used as the curing agent,
An adhesive was prepared in the same manner as in Example 1 except that component B was not used at all. A test piece was prepared using this adhesive according to the method described above, and the adhesiveness was evaluated in the same manner as in Example 1.

The evaluation results for adhesion ++ are shown in Table 1.

Table 1 Tensile shear fracture Tensile shear fracture strength Condition Strength Condition (kg/cm2) (kg/cm2) Example 1 60 AA 56 8B Example 2
76 AA 54 8B Comparative Example 1
50 CC35CC Comparative Example 2 79 BB 34 CC fracture state: The sheared part of the test piece was visually observed, and F
Evaluation was made according to the criteria described below.

AA: Destruction of SMC adherend material BB: Destruction of SMC adherend material and interfacial peeling are mixed CC: Interfacial peeling [Example 3] Curing agent is produced by reaction between mud diene liquid rubber and aliphatic polyamine. 30 parts of substance (component B) and 1 part of persamide
25 (component C; manufactured by Daiichi General ■, amine value 345) 2
An adhesive was prepared in the same manner as in Example 1 except that the amount was 0 parts. A test piece was prepared using this adhesive according to the method described above, and the adhesiveness was evaluated in the same manner as in Example 1.

The adhesive evaluation results are shown in Table 2.

[Example 4] An adhesive was prepared in the same manner as in Example 3, except that the curing agents were 20 parts of component B and 30 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 3.

The adhesive evaluation results are shown in Table 2.

[Example 5] An adhesive was prepared in the same manner as in Example 3 except that the co-curing agent was 10 parts of component B and 40 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 3.

The adhesive evaluation results are shown in Table 2.

[Comparative Example 3] Only 50 parts of component C (persamide 125) was used as the curing agent,
An adhesive was prepared in the same manner as in Example 3 except that component B was not used at all. A test piece was prepared using this adhesive by the method described above, and the adhesiveness was evaluated in the same manner as in Example 3.

The adhesive evaluation results are shown in Table 2.

Table 2 23℃ 80℃ Tensile shear fracture Tensile shear fracture strength Condition Strength Condition (kg/cm2) (kg/cm2) Example 3 67 AA 51 8B Example 4
80 AA 64 8B Example 5 8
3 AA 39 8B Comparative Example 1. 50
CC35CC comparative example 3 77 88 3
9 The test results of the comparative example work are reproduced for CC reference. The observation method and evaluation criteria for the state of destruction are the same as in Table 1.

From Tables 1 and 2, it is clear that the epoxy resin adhesive composition of the present invention is suitable for adhesives using a reaction product of a diene liquid rubber and an aliphatic polyamine or a polyamide resin curing agent alone as a curing agent. It is clear that it has superior adhesive properties compared to other agents.

[Example 6 Co-curing agent 1. -40 parts of the reaction product of the diene liquid rubber described in 1x and an aliphatic polyamine (component B), and persamide 140 (component C; manufactured by Daiichi Ceneral ■, amine value 38
5) An adhesive was prepared in the same manner as in Example 1 except that the amount was 8 parts. A test piece was prepared using this adhesive by the method described above, and the adhesiveness was evaluated in the same manner as in Example 1.

The adhesive evaluation results are shown in Table 3. Example 7 An adhesive was prepared in the same manner as in Example 6, except that the curing agent was 30 parts of component B and 16 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 6.

Table 3 shows the adhesive evaluation results.

[Example 8] An adhesive was prepared in the same manner as in Example 6, except that the curing agents were 20 parts of component B and 24 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 6.

Table 3 shows the adhesive evaluation results.

[Example 9] An adhesive was prepared in the same manner as in Example 6 except that the co-curing agent was 10 parts of component B and 32 parts of component C.

Using this adhesive, a test piece was created by the method described above,
Adhesion was evaluated in the same manner as in Example 6.

Table 3 shows the adhesive evaluation results.

Table 3 Tensile shear fracture Tensile shear fracture strength Condition Strength Condition (kg/cm2) (kg/cm2) Example 6 57 AA 48 8B Example 7
64 AA 65 8B Example 8 7
1 AA 59 8B Example 9 78
The observation method and evaluation criteria for the fracture state of AA 50 8B are the same as in Table 1.

Patent applicant: Ube Industries Co., Ltd. Representative Patent Attorney Yasuo Yanagawa

Claims (1)

[Claims] 1. Component A: Molecular weight 10 with carboxyl group at the end
Epoxy compound component containing at least one type of epoxy compound modified with diene liquid rubber of 00 to 7000 (however, the amount of diene liquid rubber component in the epoxy compound component is within 35% by weight); Component B: General formula H_2N(C_2H_4NH)_nH(
(where n is an integer of 2 to 5) and a diene liquid rubber having a molecular weight of 1000 to 7000 having a carboxyl group at the end, the molar ratio of the aliphatic polyamine compound to the diene liquid rubber is is 5
-100; and component C: a polyamide resin curing agent, wherein the blending amounts of component B and component C relative to component A are the same as those of component B and component C. The total number of active hydrogens contained is greater than or equal to the number of epoxy groups contained in component A, and B out of the total amount of component B and component C.
An epoxy resin adhesive composition characterized in that the components are present in amounts ranging from 10 to 90% by weight.