JPS59215313A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:A resin composition having rapid curability, excellent storability at room temperature and excellent properties, prepared by mixing a liquid rubber- modified epoxy resin with dicyandiamide, tetramethylguanidine and 3-(substituted phenyl)-1,1,-dimethylurea. CONSTITUTION:100pts.wt. liquid epoxy resin based on a rubber-modified epoxy resin obtained by reacting an epoxy resin with a carboxyl group-containing polymer is mixed with 2-20pts.wt. dicyandiamide, 0.1-0.5pt.wt. tetramethylguanidine and 0.5-5pts.wt. 3-(substituted phenyl)-1,1-dimethylurea. The rubber component of the rubber-modified epoxy resin is preferably 3-50wt%. Because of easy availability and safety, 3-(p-chlorophenyl)-1,1-dimethylurea or 3-(3,4-dichlorophenyl)- 1,1-dimethylurea are preferred as the 3-(substituted phenyl)-1,1-dimethylurea.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has fast curing properties, excellent storage stability at room temperature, good flowability during heat curing, and excellent adhesion.
This invention relates to a one-component epoxy resin composition that has excellent heat resistance and impact resistance.

Epoxy resin has excellent properties such as electrical insulation, heat resistance, corrosion resistance, and adhesiveness, and its usage form can be selected as appropriate from liquid, paste, sheet, and powder, and can be used by changing the formulation. It is widely used in various fields of application because it can impart properties to the cured product depending on the purpose.

However, -liquid heat-curing epoxy resins have conventionally been fast-curing, have excellent storage stability at room temperature, have good flowability during heat-curing, and have excellent adhesion, thermal resistance, and impact resistance. No material with superior properties has been found, and as a result, it has been subject to limitations in terms of usage. In particular, one way to improve adhesion and impact resistance is to add a rubbery polymer to the epoxy resin, but in this case, since a high molecular weight rubber component is included, flowability during heat curing generally decreases.

In addition, as a method to improve flowability during heat curing, n-
The use of reactive diluents such as butyl grindyl ether and phenyl curindyl ether, or non-reactive diluents such as dibutyl phthalate reduces flowability, but has the disadvantage of lowering heat resistance.

As a result of extensive research in view of the above circumstances, the inventors used an epoxy resin whose main component is a rubber-modified epoxy resin, used a specific amount of dianediamide as a curing agent, and discovered that two specific types of It was discovered that by using specific amounts of each of the curing accelerators, a liquid heat-curable epoxy resin composition could be obtained that achieved the above-mentioned excellent properties, and this invention was achieved.

That is, this invention uses 2 to 20 parts by weight of dicyandiamide and TEF to 100 parts by weight of a liquid epoxy resin whose main component is a rubber-modified epoxy resin obtained by reacting an epoxy resin with a carpoquinyl group-containing rubbery polymer. The present invention relates to an epoxy resin composition characterized in that it contains 01 to a methylguanidine, s weight i part, and 0.5 to 5 weight parts of 3-substituted phenylroot 1-dimethylurea.

Since the epoxy resin composition of this invention uses a rubber-modified epoxy resin, it forms a sea-island structure after being heated and cured.
This rubber phase acts to eliminate the decrease in adhesion of the cured epoxy resin by alleviating the residual core force during curing, and also increases energy absorption capacity and improves impact resistance.The rubber-modified epoxy resin used Because the carboxyl groups of the rubbery polymer react with the epoxy resin, there is a bond at the interface between the rubber phase and the epoxy resin phase. The strength of the resin is maintained, and the physical properties do not deteriorate due to poor compatibility, which occurs when an epoxy resin and a rubbery polymer are simply mixed.

On the other hand, when a rubber-modified epoxy resin is not used, there is no stress-relaxing component, so the residual stress during curing is maintained, resulting in a strained resin coating, which reduces adhesion and reduces durability. The epoxy resin composition of the present invention also has a specific amount of tetramethylguanidine added to it by curing acceleration stabilization to alleviate the decrease in flowability caused by using the rubber-modified epoxy resin. 3-3, which has fast curing properties and long shelf life at room temperature.
This composition is supplemented by the combined use of a specific amount of substituted phenyl-11-dimethylurea to provide a composition that is fast-curing, has excellent storage stability at room temperature, and has good flowability upon heat-curing.

On the other hand, when only tetramethylguanidine is used as a curing accelerator, the flowability is good, but both rapid curing properties and storage stability cannot be satisfied. In addition, when only 3-substituted phenyl-J.agethyl urea is used as a curing accelerator, it is possible to achieve relatively good storage stability and fast curing, but the viscosity increases during heat curing. It has the disadvantage of being boring and having poor flowability.

Furthermore, since the epoxy resin composition of the present invention does not use the aforementioned diluent used to improve flowability, the epoxy resin composition does not deteriorate side heat properties due to such a diluent. can maintain good heat resistance.

Therefore, the epoxy resin composition of the present invention has good curing workability and can be used in paints, adhesives, sealants, molding, casting, impregnation, etc. under high temperature heating atmospheres and vibrations. However, there is no risk of problems such as poor appearance, reduced adhesion, and reduced airtightness, and the above-mentioned characteristics inherent to epoxy resins can be well exhibited for these uses.

In this invention, the epoxy resin used for preparing the rubber-modified epoxy resin is preferably bisphenol A epoxy resin, but other epoxy resins include bisphenol F epoxy resin, cycloaliphatic epoxy resin, and hydantoin epoxy resin. Resins, novolac type epoxy resins, glycidyl ester type Evoquin resins, etc. can be used alone or in combination of two or more types.

In addition, the epoxy equivalent of the epoxy resin is usually 100~
About 3,500 epoxy groups are used, and those having an average of two or more epoxy groups in one molecule are preferably used.

Furthermore, although epoxy resins that are liquid at room temperature are usually used, solid epoxy resins may also be used.

The carboxyl group-containing rubbery polymer used in this invention usually has a molecular weight of 1,000 to 5,000, preferably 3,000 to 4,000, and contains an average of 15 carboxyl groups per molecule. -2.5, preferably 1.8-2.4, and linear ones having carboxyl groups at both ends of the molecule are preferably used.

A particularly preferred example of such a polymer is carboxyl group-containing acrylonitrile-butadiene copolymer rubber. Hiker CTBN (B) is a commercially available product.
, F, manufactured by Goodrich Cbemica 1; l-modified nitrile rubber containing about 10 to 30% acrylonitrile and having an acid equivalent of 0.07 per 1001, number average molecular weight 3,400). There are 13 CTBNs.
00X8.1300X9.1300X13.1300X
15 etc. can be mentioned.

Another suitable example of the rubbery polymer is carboxyl group-containing butadiene rubber. Examples of these include Nippon Soda's Nl5SO-1! B, C
-Can list IQQQ, C-2000, etc.

The rubber-modified epoxy resin used in this invention can be obtained by melt-mixing the epoxy resin and the rubbery polymer at about 70 to 160°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 a small amount of carboxyl groups remain, they can be used in the present invention, and generally, unreacted carboxyl groups of about 10 times or less of the initial carboxyl group amount may remain.

The rubber component content in the rubber-modified epoxy resin is preferably 3 to 50% by weight. This rubber component content (weight%)
is the value expressed by X〒π×100 when the amount of epoxy resin used in producing the rubber-modified epoxy resin is 8 parts by weight and the carboxyl group-containing rubbery polymer is 8 parts by weight. When the rubber component content is low, the cured product obtained from the epoxy resin composition of the present invention is less likely to exhibit stress relaxation effects due to the addition of the rubber component, resulting in poor adhesion, impact resistance, and the like. Furthermore, if the rubber component content is too high, properties such as heat resistance and adhesiveness will be poor.

The rubber-modified epoxy resin used in this invention needs to maintain its reactivity as an epoxy resin even after all the carboxyl groups of the rubbery polymer have reacted with the epoxy groups.

Therefore, the epoxy equivalent of the rubber-modified epoxy resin used in this invention is usually 200 to 5,000 equivalents, preferably 2
The amount is 50 to 4,000 equivalents. In order to obtain such a rubber-modified epoxy resin, for example, when producing the resin, it is preferable to blend a carboxyl group-containing rubbery polymer and an epoxy resin such that the amount of epoxy groups is 2.3 or more equivalents per 1 equivalent of carboxyl groups. .

In this invention, the above-mentioned rubber-modified epoxy resin may be used alone as the liquid epoxy resin, or a rubber-modified epoxy resin and an unmodified epoxy resin may be used in combination. As this unmodified epoxy resin, the epoxy resin used in the production of rubber-modified epoxy resin can be used, and in this case, the rubber component content in the liquid epoxy resin mixture expressed by the following formula is 3 to 3. Preferably, the weight is 50% by weight.

1 □ 10
2 to 20 parts by weight, preferably 4 to 10 parts by weight
Use within the range of parts by weight. - This is because if it is less than 2 parts by weight, curing will be delayed even if a curing accelerator is used, and if it exceeds 20 parts by weight, dicyandiamide will be excessive and will tend to remain as an unreacted product.

In this invention, it is important to use specific amounts of tetramethylguanidine and 3-substituted phenyl-11-dimethylurea as curing accelerators. Tetramethylguanidine is 01 to 100 parts by weight of epoxy resin.
It is used in an amount of 0.5 parts by weight, preferably in a range of 0.1 to 0.3 parts by weight. This is because if the amount is less than 0.1 part by weight, curing will be delayed and the flowability will be reduced, and if it is more than 0.5 parts by weight, the storage stability will be deteriorated and it cannot be put to practical use.

The other 3-substituted phenyl-1,1-dimethylurea, 3-CP-10ruphenyl)-1,1-dimethylurea and 3-(3,4-dichlorophenyl)-1,1-
Dimethylurea is particularly suitable from the viewpoint of ease of availability and safety, and in addition, 3-(1)--bromphenyl)-1-dimethylurea, 3-(p-anisyl)-1
・1-dimethylurea, 3-(P-nitrophenyl)-1
- 1-dimethylurea etc. can also be used.

Such 3-substituted phenyl-1,1-dimethylurea is used in an amount of 05 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the epoxy resin. This is because if the amount is less than 0.5 parts by weight, the curing will be delayed, and if it is more than 5 parts by weight, the flowability during heat curing will be poor.

The epoxy resin composition of the present invention may also contain a silane coupling agent, which greatly improves the water resistance of the cured product.

Examples of this silane coupling agent include X5iY
3 (X is a non-hydrolyzable organic group such as a vinyl group, methacrylogine propyl group, aminoalkyl group, mercaptoalkyl group, ebony/alkyl group, Y is a hydrolyzable group such as a halogen or alkoxy group) Silane compounds represented by the following are preferred, and specific examples include γ-aminepropyltriethoxinelan and vinyltriacetoxinesilane. The silane coupling agent is usually used in an amount of 5 parts by weight or less, preferably 0.2 to 2 parts by weight, per 100 parts by weight of the epoxy resin.

In addition, in the epoxy resin composition of the present invention, silica, clay, gypsum, calcium carbonate, quartz powder, kaolin, mica, alumina, hydrated alumina, talc, dolomite, zircon, titanium compounds, molybdenum compounds, antimony compounds, etc. Various commonly used additive components such as fillers, pigments, anti-aging agents, etc. can be appropriately blended depending on the use and desired properties.

Examples and comparative examples of the present invention will be shown below.

In addition, all parts below mean parts by weight.

Example 1 80 parts of Epicoat 828 (manufactured by Yuka NEL Epokin Co., Ltd. epoxy resin average molecular weight 38α-1 average number of epoxy groups 2, epoxy equivalent 185 to 1.95) and Hiker C
TBN 13QOX8 (B, F, GoodricbC
20 parts of butadiene-acrylonitrile copolymer rubber (average molecular weight 3,400, average carboxyl group number 1.9) manufactured by Hemica 1 Co., Ltd. was dissolved and reacted at 125°C for 3 hours in a mixing pot to form a rubber-modified epoxy resin (epoxy equivalent weight 250).
] was obtained.

50 parts of this rubber-modified epoxy resin, Epicoat 828 (
50 parts of dicyandiamide, 0.2 parts of tetramethylguanidine, 3-(3,4-dichlorophenyl)
-2 parts of 1,1-dimethylurea, 50 parts of 5S, and 70 parts of calcium carbonate manufactured by Nitto λka Co., Ltd. were dissolved and kneaded for 1 hour at room temperature in a mixing pot, and the kneaded mixture was passed through three rolls. An epoxy resin composition was obtained.

Comparative Example 1 An epoxy resin composition was obtained in the same manner as in Example 1 except that the amount of tetramethylguanidine was changed to o and oss.

Comparative Example 2 An epoxy resin composition was obtained in the same manner as in Example 1 except that the amount of tetramethylguanidine was changed to 0.6 parts.

Comparative Example 3 An epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of 3-(3,4-dichlorophenyl)-1,1-dimethylurea was changed to 0.3 parts.

Comparative Example 4 An epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of 3-(3,4-dichlorophenyl)-1-1-dimethylurea was changed to 6 parts.

Comparative Example 5 An epoxy resin composition was obtained in the same manner as in Example 1 except that 3-(3.4-')chlorophenyl)-1.1-dimethylurea was not used.

Comparative Example 6 An epoxy resin composition was obtained in the same manner as in Example 1 except that tetramethylguanidine was not used.

Example 2 100 parts of the rubber-modified Evoquin resin obtained in Example 1, 18 parts of dicyandiamide, 01 part of tetramethylguanidine, 4 parts of 3-(P-chlorophenyl]-1,1-dimethylurea, S-talc (Hatsubon) 30 parts of silane coupling agent KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved and kneaded for 3° at room temperature in a mixing pot, and the kneaded mixture was passed through three rolls to form an epoxy resin composition. Obtained.

Comparative Example 7 Tetramethylguanidine and 3-(p-chlorophenyl)
An epoxy resin composition was obtained in the same manner as in Example 2, except that 1 part of 2-phenylimidazole was used instead of -1,1-dimethylurea.

Comparative Example 8 Dicyandiamide, tetramethylguanidine and 3C
The same procedure as Example 2 was carried out, except that 10 parts of Anchor 1040 (trade name of a boron fluoride curing agent manufactured by Anchor Chemical Co., Ltd.) was used instead. An epoxy resin composition was obtained.

Example 3 Epikote 828 (950 parts above) and carboxyl group-containing butadiene rubber (Nl550-r' manufactured by Nippon Soda Co., Ltd.)
T3. C-2000; average molecular weight 2000, average number of carboxyl groups 2] 50 parts was dissolved in a mixing pot at 125°G for 3
Rubber-modified epoxy resin (epoxy equivalent: 4
80) was obtained.

80 parts of the obtained rubber-modified epoxy resin, Epico-1-1
001 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd., average molecular weight 900, average number of epoxy groups 1.9, epoxy equivalent weight 4
50 to 500) and 3 parts of dicyandiamide were melt-mixed by heating at 70°C for 1 hour in a mixing pot, and after further cooling to room temperature, 05 parts of tetramethylguanidine and 3 parts of tetramethylguanidine were mixed.
0.5 parts of -(3,4-dichlorophenyl)-1,1-dimethylurea was added and kneaded at room temperature for 1 hour, and the kneaded product was passed through three rolls to obtain an epoxy resin composition.

Comparative Example 9 Epicoat 82 instead of 80 parts of rubber-modified epoxy resin
An epoxy resin composition was obtained in the same manner as in Example 3 except that 80 parts of 8 (described above) were used.

Each of the epoxy resin compositions obtained in the above Examples and Comparative Examples was cured under the heat curing conditions shown in Tables 1 and 2 below, and various properties were tested.

The results are shown in Tables 1 and 2 below. The test method for each characteristic is as follows.

<Viscosity> Using Brookfield rotational viscometer, rotor No. 7,
Measurement was performed at 20'C and 10 rpm according to Jll-6833.

Fluidity> Composition 0107 was placed on an aluminum plate (1 cm x 1 cm)
The distance flowed from the lower end of the sample was measured by applying it on top and setting it on an inclined plate with an angle of inclination of 30° and curing it.

<Gelification time> Measured at 150°C according to JIS-145909.

<Fast Curing Properties> It was determined whether or not the samples were completely cured by heating at 150° C. for 115 minutes, and those that were completely cured were graded ゛ (◯), and those that were not cured were graded (x).

Preservation Stability> The presence or absence of gelation after oral administration was examined when the composition was stored at 4-00C. Evaluation was made for those that did not gel after 20 days (○), those that gelled within 10 to 20 days (△), and 1
Those that gelled within 0 days were marked (×).

<T-type peel adhesive strength> Measured according to Jl, S-6854 at 23°C using an aluminum plate (JIS-tI4α0O1A1050P) as an adherend.

Glossy Ruby Impact Test> Ill! at 23°C according to JIS-146911! 1
+ Established.

As is clear from the results in the above table, the epoxy resin composition according to the present invention has the characteristics of good flowability during heat curing, excellent storage stability, and fast curing, and the cured product Adhesion and impact resistance are also sufficient. Therefore, this epoxy resin composition can be suitably used for various purposes such as molding, casting, impregnation, and adhesion, and can improve heat-curing workability, shorten time, and reduce energy consumption. I can do it.

Claims (4)

[Claims] (1) A liquid epoxy resin whose main component is a rubber-modified epoxy resin obtained by reacting an epoxy resin with a carboxyl group-containing rubbery polymer.For every 100 fF (m), 2 to 20 MN parts of dicyandiamide, 11 parts of tetramethylguanidine O An epoxy resin composition containing ~0.5 parts by weight and 0.5 to 5 parts by weight of 3-substituted phenyl-].1-dimethylurea, (2) The rubber component content in the liquid epoxy resin is 3 to 50
The epoxy resin composition according to claim (1) in terms of weight 3゜ (3) 3fl substituted phenyl-1,1-dimethylurea 3-(1)-chlorophenyl)-1, ]-cymethy/
"Urine: 41: Taha 3-(3,4-dichlorophenyl)-dimethylurea" Claim No. 1 (1)
) or (2). (4) The epoxy resin composition according to any one of claims (1) to (31), which contains a silane coupling agent.