JPS61228060A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:An epoxy resin composition, having improved flexibility, impact resistance and chemical resistance, comprising a specific rubber modified epoxy resin, a phenoxy resin, a curing agent component and optionally an epoxy resin. CONSTITUTION:(A) a rubber modified epoxy resin obtained by reacting an epoxy resin, preferably a novolak type epoxy resin having two or more epoxy groups on average in one molecule with carboxyl group-containing butadiene rubber or butadiene acrylonitrile copolymer rubber, or a mixture of the rubber modified epoxy resin and the epoxy resin, containing 3-70wt% rubber component content, is blended with (B) 5-90wt% based on the resin components of a phenoxy resin having 10,000-100,000 molecular weight and (C) a curing agent component, preferably dicyandiamide or dicyandiamide and a curing promoter, to give the aimed composition.

Description

[Detailed description of the invention] [Technical field J The present invention relates to epoxy resin compositions.

[Prior art]

Epoxy resin has excellent properties such as electrical insulation, heat resistance, corrosion resistance, and adhesiveness, and can be used in liquid, paste, sheet, and powder forms, so it is used in a variety of fields. ing. 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, even epoxy resins with such excellent properties are inferior in terms of flexibility and impact resistance, and to improve this, the use of flexible epoxy resins and rubber-modified epoxy resins have been considered for some time. , improvements have been made. However, when using the above resins to obtain sufficient flexibility and impact resistance, the excellent chemical resistance that epoxy resins originally had will be lost, and the flexibility and impact resistance will be reduced. It was difficult to achieve both chemical resistance and chemical resistance.

[Purpose and outline of the invention]

In view of the above circumstances, the present inventors conducted extensive research and found that a resin component obtained by mixing a phenoxy resin with a rubber-modified epoxy resin, or a resin component obtained by further mixing an epoxy resin or a phenoxy resin with the above-mentioned rubber-modified epoxy resin. We have discovered that an epoxy resin composition obtained by containing a resin component and a curing agent component has excellent flexibility, impact resistance, and chemical resistance, and we hereby present the present invention. The invention was completed.

That is, the present invention includes a rubber-modified epoxy resin obtained by reacting an epoxy resin with butadiene rubber or butadiene acrylonitrile copolymer rubber having a carboxyl group, a phenoxy resin, a curing agent component, and, if necessary, an epoxy resin. The present invention relates to a characteristic epoxy resin composition.

〔Effect of the invention〕

In this way, in the present invention, by using a rubber-modified epoxy resin, heat resistance and chemical resistance are maintained, and high adhesion is achieved due to the stress relaxation ability of the rubber component, while on the other hand, by using a phenoxy resin, It can exhibit excellent properties of flexibility and impact resistance. In addition, the rubber-modified epoxy resin used in the present invention forms a sea-island structure after being heated and cured, and this rubber phase relieves the residual stress during curing, thereby preventing a decrease in the adhesion of the epoxy resin composition. I can do it. That is, in the rubber-modified epoxy resin used, since the carboxyl group of the rubbery polymer and the epoxy resin are reacted, there is a bond at the interface between the rubber phase and the epoxy resin phase, so it is difficult to form a two-phase system like a seabird structure. Even if it is, the strength of the cured resin is maintained, and the physical properties do not deteriorate due to poor compatibility as in the case of simply mixing an epoxy resin and a rubbery polymer.

On the other hand, when a rubber-modified epoxy resin is not used, there is no stress-relaxing component, and residual stress is retained during curing, resulting in a strained resin coating and reduced adhesion.

[Structure of the invention]

In the present invention, bisphenol A type epoxy resin is suitable as the epoxy resin used to produce the rubber-modified epoxy resin, but other types of epoxy resins include bisphenol F type epoxy resin, cycloaliphatic epoxy resin, hydantoin type epoxy resin, and noporaf type epoxy resin. Type epoxy resins, glycidyl ester type epoxy resins, etc. can be used alone or in combination of two or more types. Further, the epoxy equivalent of the epoxy resin is usually about 100 to 3,500. This rubber-modified epoxy resin retains reactivity as an epoxy resin even after reacting with the carboxyl group of the rubbery polymer and the epoxy group of the epoxy resin, so the epoxy resin contains an average of two or more epoxy groups in one molecule. Preferably.

As the butadiene rubber or butadiene-acrylonitrile copolymer rubber having a carboxyl group used in the present invention, one having a linear molecular structure is preferably used. Also, this rubbery polymer usually has a molecular weight of 10
00 to 5000. The number of carboxyl groups contained per molecule is usually 1.5 to 2.5 on average, preferably 1.8
~2.4, and those having carboxyl groups at both ends of the molecule are preferably used. As a commercial product of such butadiene rubber or copolymer rubber, N15so PB
, C-1000, c-2000 (butadiene rubber manufactured by Nippon Soda Co., Ltd., average number of carboxyl groups 2), Hyca
r CT B NH3 (B, F, Goodr'ich
Made by Chem-ica1, acrylonitrile is approximately 10
Contains ~30% by weight, acid equivalent per 100g is 0.0
7 liquid nitrile rubber, number average molecular weight 3400). Hycar CTBN19fl is 1300X
Examples include 8.1300x9.1300x13.1300x15.

To produce the rubber-modified epoxy resin used in the present invention, the above epoxy resin and rubbery polymer are heated at 80°C to 1°C.
It can be obtained by melt-mixing at about 80°C for 0.5 to 4 hours. The rubber-modified epoxy resin obtained by melt-mixing at this time is substantially free of carboxyl groups.

However, even if some carboxyl groups remain, they can be used in this invention. In general, even if unreacted carboxyl groups remain in an amount of about 10% or less of the initial amount of carboxyl groups, they can be used in the present invention.

The rubber component content in the rubber-modified epoxy resin is preferably 3 to 70% by weight. The ratio of this rubber component is the epoxy resin used when manufacturing the rubber modified epoxy resin.
When the copolymer rubber is taken as part B, the value is expressed as xlOO% by weight. The ratio is the value A + * + B expressed in X100% by weight. When the rubber component content decreases, the stress relaxation effect due to the addition of the rubber component is difficult to be observed in the cured product obtained from the composition of the present invention, and the adhesion improves. This is because, if the rubber component content is too high, properties such as heat resistance and chemical resistance will become inferior.

Furthermore, the rubber-modified epoxy resin used in the present invention needs to maintain its reactivity as an epoxy resin even after all the carboxyl groups of the rubbery polymer react with the epoxy groups. Usually, the epoxy equivalent of the rubber-modified epoxy resin used in this invention is 200 to 5000 equivalents, preferably 250 to 400 equivalents.
It is considered as 0 equivalent.

In order to obtain such a rubber-modified epoxy resin, for example, during production of the resin, a carboxyl group-containing rubbery polymer and an epoxy resin are blended such that the amount of epoxy groups is 2.3 or more equivalents per one equivalent of carboxyl groups.

As the phenoxy resin used in the present invention, a phenoxy resin having a high molecular weight, preferably having a molecular weight in the range of 10,000 to 1 ooooo, is used in order to exhibit excellent properties such as flexibility and impact resistance. As a commercially available product, phen
oxy P K HHSP K HJ, P K H
C (manufactured by Union Carbide) and the like. This phenoxy resin content is C+D, where the amount of rubber-modified epoxy resin used when mixing the resin components is 0 parts and the amount of phenoxy resin is D parts. Also, when mixing the resin components, add epoxy resin A'
The phenoxy resin content is preferably in the range from 5 to 90% by weight, where the value C+I)+A' is expressed in X100% by weight. When the phenoxy resin content is low, sufficient flexibility and impact resistance cannot be obtained, and when it is high, heat resistance and chemical resistance are reduced.

The curing agents used in the present invention include mercaptan curing agents, amine curing agents, polyamide curing agents, boron curing agents, dicyandiamide curing agents, hydrazide curing agents, imidazole curing agents, phenolic curing agents, Examples include acid anhydride curing agents. However, from the viewpoint of storage stability when made into a one-component composition, dicyandiamide-based curing agents are preferred. When dicyandiamide is used alone as a curing agent, the curing temperature is high and the curing time may be long. In that case, it is recommended to use dicyandiamide and a curing accelerator together. Examples of such curing accelerators include alkyl-substituted guanidine, 3-substituted phenyl-1. Examples include l-dimethylurea type, imidazole type, imidacilline type, tertiary amine type, monoaminopyridine type, and amine imide type.

In the present invention, if a silane coupling agent is further used in the mixture of the resin component and the curing agent component, water resistance, chemical resistance,
Adhesion can be further improved. Examples of such silane camping agents include X S i Y
3 (X is a vinyl group, a methacryloxypropyl group,
A silane compound represented by a non-hydrolyzable organic group such as an aminoalkyl group, a mercaptoalkyl group, or an epoxyalkyl group; Y is a hydrolyzable group such as a halogen or an alkoxyl group is preferable; specifically, γ -Ami! Examples include propyltriethoxysilane and vinyltriacetoxysilane. The silane coupling agent is 5 parts by weight or less, preferably 0.2 parts by weight based on 100 parts by weight of the resin component.
~3M parts are used.

Furthermore, in the epoxy resin composition of the present invention, silica,
Fillers and pigments such as clay, gypsum, calcium carbonate, barium sulfate, quartz powder, glass fiber, kaolin, mica, alumina, hydrated alumina, aluminum hydroxide, talc, dolomite, zircon, titanium compounds, molybdenum compounds, antimony compounds, etc. , anti-aging agents, and other commonly used additive components can be appropriately blended depending on the use and desired properties.

The composition of the present invention also includes cases where an epoxy resin is further contained, and the epoxy resin used in this case includes:
The same resins as the epoxy resins used to produce rubber-modified epoxy resins can be mentioned, but from the viewpoint of chemical resistance, it is preferable to use epoxy resins that have an average of two or more epoxy groups in one molecule. .

The epoxy resin composition of the present invention not only can be effectively used in fields in which epoxy resin compositions have traditionally been used, but also has strong demands for flexibility, chemical resistance, and impact resistance. It is also effective in various fields where conventional epoxy resin compositions cannot be used, such as liquid adhesives for bonding parts of electrical equipment and automobile motors, adhesive sheets, and molding materials. It can be used.

〔Example〕

Examples and comparative examples of the present invention will be shown below. However, in the following, parts and % mean parts by weight and % by weight.

Example 1 Copolymerization of 80 parts of bisphenol A type epoxy resin with an epoxy equivalent of 190 and a molecular weight of about 380, and butadiene-acrylonitrile having carboxyl groups at both ends of the molecule with a molecular weight of 3400, an average number of carboxyl groups of 1.9, and an acrylonitrile content of 18%. Melt 20 parts of rubber in a kettle at 125°C.
The reaction was carried out for 3 hours to obtain a rubber-modified epoxy resin.

50 parts of this rubber-modified epoxy resin, molecular weight approximately 30,000
After cooling, 8 parts of dicyandiamide and 5 parts of 3-(3,4-dichlorophenyl)-1,1-dimethylurea were mixed at room temperature to obtain an epoxy resin composition. Ta. Table 1 shows the properties of the final cured product after heat curing at 150°C for 30 minutes.

Example 2 50 parts of the rubber-modified epoxy resin used in Example 1, 20 parts of phenoxy resin, and 30 parts of bisphenol A type epoxy resin having an epoxy equivalent of 190 and a molecular weight of about 380 were heated and melt-mixed, and after cooling, 8 parts of dicyandiamide, and 3
5 parts and 1 m of -(3,4-dichlorophenyl)-1,1-dimethylurea were combined to obtain an epoxy resin composition. 150℃
Table 1 shows the properties of the final cured product after heat curing for 30 minutes.

Example 3 10 parts of the rubber-modified epoxy resin used in Example 1, 84 parts of phenoxy resin, and 6 parts of bisphenol A type epoxy resin having an epoxy equivalent of 190 and a molecular weight of about 380 were heated and melted and mixed, and after cooling, 8 parts of dicyandiamide, and 3
- 5 parts of (3,4-dichlorophenyl)-1,1-dimethylurea were mixed to obtain an epoxy resin composition. 150
Table 1 shows the properties of the final cured product after heat curing for 30 minutes at °C.

Comparative Example 1 An epoxy resin composition was obtained in the same manner as in Example 1 except that only 100 parts of the rubber-modified epoxy resin used in Example 1 was used as the resin component.

Table 1 shows the properties of the final cured product after heat curing at 150°C for 30 minutes.

Comparative Example 2 An epoxy resin composition was obtained in the same manner as in Example 1 except that 3 parts of the phenoxy resin used in Example 1 and 50 parts of bisphenol A type epoxy resin were used as resin components. Table 1 shows the properties of the final cured product after heat curing at 150'C for 30 minutes.

Comparative Example 3 97 parts of the rubber-modified epoxy resin used in Example 1 and 3 parts of phenoxy resin were used as resin components.

Otherwise, the same procedure as in Example 1 was carried out to obtain an epoxy resin composition. Table 1 shows the properties of the final cured product after heat curing at 150°C for 30 minutes.

Comparative Example 4 An epoxy resin composition was obtained in the same manner as in Example 1 except that 5 parts of the rubber-modified epoxy resin used in Example 1 and 95 parts of phenoxy resin were used as resin components. 1
Table 1 shows the properties of the final cured product after heat curing at 50°C for 30 minutes.

Example 4 20 parts of 3.4-epoxycyclohexylmethyl-3°4-epoxycyclohexancarboxylate and 80 parts of butadiene rubber having a molecular weight of 1000 and an average number of carboxyl groups of 2 were melted in a mixing pot to melt 150 parts of the carboxyl group.
The reaction was carried out at ℃ for 1.5 hours to obtain a rubber-modified epoxy resin.

30 parts of this rubber-modified epoxy resin, molecular weight approximately 25,000
50 parts of phenoxy resin and 170 parts of epoxy equivalent
, bisphenol F type epoxy resin 2 with a molecular weight of about 350
A two-component epoxy resin composition was obtained by heating and melt-mixing 0 parts of the mixture to form a main component, and then heating and melt-mixing 40 parts of tetrahydrophthalic anhydride and 1 part of benzyldimethylamine as curing agent components. The main ingredient and curing agent ingredient are 10/
Table 2 shows the properties of the final cured product after mixing at a ratio of 4 (weight ratio) and heating at 150°C for 1 hour.

Comparative Example 5 An epoxy resin composition was obtained in the same manner as in Example 4, except that 50 parts of the rubber-modified epoxy resin and 50 parts of phenoxy resin used in Example 4 were used as main ingredients. 1
Table 2 shows the properties of the final cured product after heat curing at 50°C for 1 hour.

Comparative Example 6 An epoxy resin composition was prepared in the same manner as in Example 4, except that 1 part of the rubber-modified epoxy resin used in Example 4, 49 parts of bisphenol F-type epoxy resin, and 50 parts of phenoxy resin were used as the main component. Obtained. Table 2 shows the properties of the final cured product after heat curing at 150°C for 1 hour.

Table 2 Example 5 80 parts of a novolac type epoxy resin with an epoxy equivalent of 175 and a molecular weight of about 370, and a butadiene-acrylonitrile copolymer with a carboxyl group having a molecular weight of 3400, an average number of carboxyl groups of 1.9, and an acrylonitrile content of 18%. 20 parts of rubber was dissolved and reacted in a mixing pot at 140°C for 2 hours to obtain a rubber-modified epoxy resin.

20 parts of this rubber-modified epoxy resin and a molecular weight of about 250
00 phenoxy resin was heated and melted and mixed, and after cooling, 1.6 parts of dicyandiamide and 0.0 parts of tetramethylguanidine were added.
．． 04 parts and 70 parts of aluminum powder were mixed at room temperature to obtain an epoxy resin composition. Table 3 shows the properties of the final cured product after heat curing at 180°C for 30 minutes.

Example 6 50 parts of the rubber-modified epoxy resin used in Example 5 and 50 parts of a phenoxy resin having a molecular weight of about 25,000 were heated and melt-mixed, and after cooling, 4 parts of dicyandiamide, 0.1 part of tetramethylguanidine, and 70 parts of aluminum powder were mixed. The components were mixed at room temperature to obtain an epoxy resin composition. 180℃30
Table 3 shows the properties of the final cured product after heating and curing.

Example 7 80 parts of the rubber-modified epoxy resin used in Example 5 and 20 parts of a phenoxy resin having a molecular weight of about 25,000 were heated and melted and mixed, and after cooling, 6.4 parts of dicyandiamide, 0.16 parts of tetramethylguanidine, and aluminum were mixed. An epoxy resin composition was obtained by mixing 70 parts of the powder at room temperature. 180℃
Table 3 shows the properties of the final cured product after heat curing for 30 minutes.

Comparative Example 7 Epoxy equivalent: 175, 100 parts of novolac type epoxy resin having a molecular weight of about 370, 8 parts of dicyandiamide, 0.2 parts of tetramethylguanidine, and 70 parts of aluminum powder
The mixture was mixed by passing through three rolls at room temperature to obtain an epoxy resin composition. Table 3 shows the properties of the final cured product after heat curing at 180'C for 30 minutes.

Comparative Example 8 20 parts of a novolak type epoxy resin with an epoxy equivalent of 175 and a molecular weight of about 370, and 80 parts of a phenoxy resin with a molecular weight of about 25,000 were heated and melt-mixed, and after cooling, 1.6 parts of dicyandiamide, 0.04 part of tetramethylguanidine, and 70 parts of aluminum powder were mixed at room temperature to obtain an epoxy resin composition. Table 3 shows the properties of the final cured product after heat curing at 180°C for 30 minutes.

However, each of the physical properties (i) to (iv) in Table 1 was measured by the following methods, and the physical properties in Tables 2 and 3 were measured by the same method as in Table 1.

i) Conforms to JIS-6850. The adherend is a steel plate (
SpCC-3DSLOOx25x1.6t+u+) single overlap) is used.

ii) According to JIS-6854. The adherend is an aluminum plate (A1050P, 150x25xO, 15t
mm) is used.

1ii) According to JIS-71)3. A No. 2 type test piece is used as the test piece shape.

iv) The composition was applied to a steel plate (SPCC-3D, 150×1
50X3.2 tmm) about 0.1-0. 2tII
After coating and curing the resin on Il and immersing it in methanol at room temperature for 1 day, observe whether the resin has blistered or peeled off.

As is clear from the above Examples and Comparative Examples, the epoxy resin composition of the present invention is excellent in heat resistance, chemical resistance, adhesion, as well as flexibility and impact resistance.

Claims (9)

[Claims] (1) An epoxy resin composition characterized by containing a rubber-modified epoxy resin obtained by reacting an epoxy resin with a butadiene rubber having a carboxyl group or a butadiene acrylonitrile copolymer rubber, a phenoxy resin, and a curing agent component. (2) The rubber component content in the rubber-modified epoxy resin is 3 or more
70% by weight of the epoxy resin composition according to claim 1. (3) The epoxy resin composition according to claim 1 or 2, wherein the phenoxy resin content in the resin component is 5 to 90% by weight. (4) The epoxy resin composition according to claim 1, 2, or 3, wherein the epoxy resin is a novolac type epoxy resin. (5) Molecular weight of phenoxy resin is 10,000 to 1,000
The epoxy resin composition according to claim 1, 2, 3, or 4, which is 00. (6) The epoxy resin composition according to claim 1, 2, 3, 4, or 5, wherein the curing agent component comprises dicyandiamide or dicyandiamide and another curing accelerator. (7) The epoxy resin composition according to claim 1, 2, 3, 4, 5, or 6, further comprising an epoxy resin. (8) The epoxy resin composition according to claim 7, wherein the rubber component content in the mixture of the rubber-modified epoxy resin and the epoxy resin is 3 to 70% by weight. (9) The epoxy resin composition according to claim 7 or 8, wherein the epoxy resin is a novolac type epoxy resin.