JPS63186727A - Epoxy resin composition having rubber elasticity - Google Patents

Abstract

PURPOSE:To obtain a resin composition which can be rapidly cured to form a rubber-like elastomer of low stress and sufficient flexibility, by mixing a flexible epoxy resin with a polythiol compound curing agent and an amine or phenol curing catalyst. CONSTITUTION:A resin composition comprising 100pts.wt. flexible epoxy resin, 10-140pts.wt. polythiol compound and 1-80pts.wt. amine or phenol. Part of said flexible epoxy resin can be replaced by other liquid or semisolid epoxy resins, but the resiliency of a rubber-like elastomer is extremely lowered and therefore decreased in recovery from compression undesirably when the amount of the flexible epoxy resin in the entire epoxy resin component is decreased to 40wt.% or below. Said flexible epoxy resin is an epoxy resin having a flexibilizing chain structure in the molecule and a low glass transition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epoxy resin composition, and particularly to a room temperature curable epoxy resin composition having low stress and rubber-like elasticity. The epoxy resin composition according to the present invention is useful as, for example, a sealing agent, a coating agent, a casting agent, a molding agent, a dipping agent, an adhesive, and the like.

[Conventional technology]

It is known to use thiol compounds as curing agents for epoxy resins. For example, Japanese Patent Publication No. 41-7236, Japanese Patent Publication No. 46-3834, Japanese Patent Publication No. 47-32319, Japanese Patent Publication No. 46-732, and British Patent No. 10
As described in No. 44715, a fast-curing epoxy resin composition has been proposed by adding a catalyst to a mixture of a polyepoxy resin and a thiol compound. The thiol compound blended into these compositions is a compound having two or more terminal mercapto groups (H3-),
The ester has a structure in which each H3-R'-C-0- group is separated by seven or more carbon atoms or a linear chain of carbon and oxygen, or the terminal mercapto group is separated by two
It is a liquid polysulfide polymer (for example, LP-3 manufactured by Thiokol).

Since then, various patents have been proposed for the purpose of eliminating the drawbacks of conventional products. For example, in JP-A-56-57820 and JP-A-59-182817, two methods are proposed for the purpose of practically extending pot life and improving workability. The first method is to add an organic carboxylic acid or its acid anhydride as a retarder, and the second method is to mix it in the form of an epoxy thiol adduct.

Furthermore, in JP-A-51-17299, by adding diaza-bicyclo alkenes and their salts as curing catalysts, a composition with faster curing speed and excellent transparency than conventional amine-based catalysts was developed. is proposed.

Furthermore, in JP-A-59-78230, monophenolic antioxidants such as 2,6-di-t-butylphenol or its alkyl-substituted derivatives, benzophenone-based ultraviolet rays, etc. A composition that cures quickly and does not cause yellowing has been proposed by containing a compound selected from absorbers, benzophenone ultraviolet absorbers, and the like.

[Problem that the invention seeks to solve]

In the room-temperature curable epoxy resin compositions for which various proposals have been made as described above, the raw material thiol compound has an H, S odor or a mercaptan odor, and the composition exhibits a brown color upon curing; Also, those that turn yellow after curing, those that cure too quickly and are impractical, those that have flexibility but lack resilience, those that are too hard and have poor impact and crack resistance, and those that have one cycle resistance. It had disadvantages such as poor quality.

Therefore, the object of the present invention is to cure quickly at room temperature and then
The object of the present invention is to propose an epoxy resin composition that is a rubber-like elastic body with low stress and high flexibility.

Another object of the present invention is to provide an epoxy resin composition that has excellent impact resistance, crack resistance and heat cycle resistance at low temperatures.

Another object of the present invention is to provide an epoxy resin composition whose cured product has an antistatic effect without incorporating a conductive material.

[Means for solving problems]

According to the above object number, the present invention provides a rubber that contains a flexible epoxy resin, a polythiol compound curing agent, and an amine or phenol curing catalyst, and that has low stress and excellent flexibility after being rapidly cured at room temperature. This is accomplished by providing an epoxy resin composition that provides a elastomeric body.

The epoxy resin composition of the present invention comprises flexible epoxy resin 1
00 parts by weight, 10 to 140 parts by weight (preferably 50 to 100 parts by weight) of a polythiol compound, and 1 to 80 parts by weight (preferably 2 to 30 parts by weight) of amines or phenols. Although a portion of the flexible epoxy resin described above can be replaced by other liquid or semi-solid epoxy resins, if the amount of flexible epoxy resin in the total epoxy resin component is less than 40% by weight, the rubber-like This is not preferable because the impact resilience is extremely reduced and the recovery properties after compression cannot be expected.

The "flexible epoxy resin" used in the present invention is an epoxy resin that has a flexibility-imparting chain structure in its molecules and has a low glass transition temperature. This flexible epoxy resin is commonly used as an additive for the purpose of improving the flexibility, softness, toughness, adhesion, etc. of general-purpose bisphenol A type epoxy resins. The flexibility-imparting chain structure includes a polyalkylene ether group, an alkylene group having 3 or more carbon atoms, and a fatty acid group having 30 or more carbon atoms.

Preferred flexible epoxy resins that can be used in the present invention are glycidyl ethers. Glycidyl ethers include, for example, polyethylene glycol diglycidyl ether, such as a compound of the structural formula, polypropylene glycol diglycidyl ether, such as a compound of the structural formula, 1,4-butanediol diglycidyl ether, a compound of the structural formula, or neopentyl glycol diglycidyl ether. That is, compounds of the structural formula can be mentioned. Furthermore, a food core polyol diglycidyl ether having the structural formula (in the formula, p+q≧2) prepared by further epoxidizing a food core polyol obtained by adding propylene oxide to bisphenol A can be used.

Flexible epoxy resins containing fatty acid residues as flexibility-imparting chain structures are, for example, partial adducts of bisphenol A type liquid epoxy resins and polymerized fatty acids with the structural formula (wherein R'' is carbon 34 unsaturated fatty acid residues), and further polymerized fatty acids (for example, linoleic acid,
A diglycidyl ester of a polymerized fatty acid whose main component is a dimer acid having 36 carbon atoms obtained by polymerizing an unsaturated fatty acid such as lylunic acid, and a compound having the structural formula % can be used.

Furthermore, a compound obtained by adding polyalkylene oxide to p-oxybenzoic acid and then epoxidizing it has a structural formula (wherein, R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 2 or more. ), and p
- A compound obtained by epoxidizing an ester of oxybenzoic acid and an alkylene diol and having the following structural formula (wherein m is an integer of 4 or more) can be used.

The polythiol compound used as a curing agent in the present invention has the general formula % (10) [where n is an integer of 3 or more, and R is a polyvalent of 3 or more (preferably trivalent to 10-valent)]. It is a residue obtained by removing n alcoholic hydrogens from alcohol, and R' is −+ cn, h
group, and m is an integer of 1 or more, preferably 1 to 7.] This is a polymercaptocarboxylic acid polyhydric alcohol ester represented by:

MR, for example, glycerin, trimethylolpropane,
Derived from pentaerythritol, polypropylene triol, polymer polyols, etc.

-a Specific examples of the ester of formula (10) are as follows. Glycerin tris (mercaptoacetate), glycerin tris (mercaptopropionate),
Glycerin tris (mercaptobutyrate), glycerin tris (mercaptopentanoate), trimethylolpropane tris (mercaptoacetate), trimethylolpropane tris (mercaptopropionate),
Trimethylolpropane tris (mercaptobutyrate), trimethylolpropane tris (mercaptohexanoate), pentaerythritol tetrakis (mercaptoacetate), pentaerythritol tetrakis (
mercaptopropionate), pentaerythritol tetrakis (mercaptobutyrate), pentaerythritol tetrakis (mercaptopentanoate), pentaerythritol tetrakis (mercaptooctanoate), and the like. Among these curing agents, viscosity, odor,
From the viewpoint of curing performance, price, etc., pentaerythritol tetrakis (mercaptopropionate) is preferred.

The curing catalyst used in the present invention is amines or phenols. Examples of amines include so-called ethyleneamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine, triethylamine, tripropylamine, tributylamine, dimethylbutylamine, dimethylpentylamine, dimethylcyclohexylamine, etc. aliphatic tertiary amines, dimethylbenzylamine, dimethylaminomethylphenol, dimethylamino-p-cresol, piperidine, α
- picoline, pyridine, 2,4゜6-tris(dimethylaminomethyl)phenol, 2-methylimidazole,
2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-
Methylimidazole, 1-cyanoethyl-2-ethyl-
4-methylimidazole, 2N-aminoethylpiperazine, 1,3.6-dorisaminomethylhenylenediamine, p-phenylenediamine, diaminophenylmethane,
Methylene dianiline, 2゜4-toluenediamine, 2,
4-diaminoanizole, 2.4-)luenediamine,
2,4-diaminodiphenylamine, 4,4-methylene dianiline, 1,3-diaminocyclohexane, 3.9
-bis(3-aminopropyl)-2,4,8,10-tetrapyro[5,5)undecane, 1,8-diazabicyclo(5,4,O)undecene-7 or polyamine,
Various amines can be mentioned, such as polyamide amine, polyamide, modified polyamine, modified polyamide amine, and modified polyamide. Furthermore, as phenols, phenol, cresol, 2.6-drimethylphenol, 2.4.6-tri-t-butylphenol, 2.
One or more compounds can be selected from compounds such as 4°6-drimethylphenol. Among these catalysts, 2°4.6-1-
Lis(dimethylaminomethyl)phenol is preferred.

Furthermore, in addition to the above-mentioned components, antioxidants, moisture resistance improvers, adhesion promoters/fillers, coupling agents, and solvents (which can be reactive. For example, as antioxidants) Transparency and weather resistance can be improved by adding organic hydroxy compounds.Also,
Organic phosphine compounds can also be added for the purpose of improving moisture resistance.

The composition of the present invention can be prepared by applying conventionally known methods as they are. For example, a method in which a curing catalyst is added and stirred to a polythiol compound, and then a flexible epoxy resin is blended therein; a method in which a flexible epoxy resin and a thiol compound are mixed and stirred, and a curing catalyst is finally added. , a method of preparing a flexible epoxy resin, a thiol compound, and a curing catalyst by mixing them all at once. Generally, a method of dispensing with a single-liquid or multi-liquid dispenser is used.

〔Effect of the invention〕

The epoxy resin composition of the present invention cures quickly at room temperature. It also provides a rubber-like elastic body with low stress and excellent flexibility. That is, it provides an elastic body that completely restores its original state within several seconds to several tens of seconds after being compressed.

Furthermore, the composition of the present invention has excellent impact resistance, crack resistance and heat cycle resistance at low temperatures.

Further, according to the present invention, the cured composition has an antistatic effect without incorporating a conductive material.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited thereto. In addition, the compounding amounts in the examples are shown in parts by weight.

A, j≦scorched earth 21H1 scorched earth Iυ” Specimens for each item of the following “physical property test” were prepared from an epoxy resin composition having the formulation shown in Table 1 below the plate.

Margin below The various components in Table 1 are as follows.

Epoxy resin A: Polypropylene glycol diglycidyl ether Epoxy resin B: Neopentyl glycol diglycidyl ether Epoxy resin C: Bisphenol A type diglycidyl ether [Epicoat 828 J manufactured by Yuka Shell Epoxy ■ Co., Ltd.] Epoxy resin D: Bisphenol F type diglycidyl ether Glycidyl ether [Araldite Polypropylenetriol tris(3-mercaptopropionate) Catalyst A: 2,4,6-tris(dimethylaminomethyl)
Phenol Catalyst B Nitriethylene Tetramine Catalyst C: N-(2-aminoethyl)piperazine Catalyst 2m-Xylene Diamine Moisture Modifier A Nitriphenylphosphine Retardant A: Methyltetrahydrophthalic Acid Antioxidant A: 2.6-diamine t-
Butylphenol antioxidant B: 2,5-toluenediol Non-reactive diluent A di-n-butyl phthalate ■Sensitivity (1) Resilience test after compression A cylindrical shape was obtained from an uncured composition with the formulation shown in Table 1. (Diameter lQmm
A molded product (test piece) with a height of 30 dragons was produced.

This was cured for one week in a room at room temperature (25°C). next,
Compression test WJ! The test piece was placed in a machine ("Strograph RJ" manufactured by Toyo Seiki Seisakusho), compressed by 1 cIn at a compression speed of 200 mm/min so that the height of the cylinder became 2/3, and left in that state for 1 minute. followed by 1000
The load was removed at a rate of mm/min, and the time required for the test piece to recover to its original height was measured.

(2) Measurement of dry-to-touch time (see JIS A-5757) In a glass container (5ho- x 100zenho x 100kens),
One specimen was flattened to a thickness of approximately 3 mm and placed under standard conditions (temperature 20 ± 2°C, relative humidity 65 ±
10%). Three locations on the surface were lightly touched with a fingertip cleaned with ethyl alcohol, and the time required for the sample to stop adhering to the fingertip was measured as the dry-to-touch time.

(3) Measurement of durometer hardness (JIS K-7215
Reference) A test molded product (thickness: 3 mm, width: 121 m or more) was prepared, and its hardness was measured using a durometer type A (Toyo Seiki Seisakusho side model).

(4) Tensile test (see JIS K-7113) Sheet-shaped molded product (11 amount x 200++n x 20 (bm)
and punched out 5 test pieces using dumbbells. This was installed in a tensile testing machine (Toyo Seiki Seisakusho model "Strograph RJ"), and the tensile strength and elongation were measured.

(5) Measurement of volume resistivity (see JIS K-6911)
A molded product with a disc shape (thickness 2±0.15 mm, diameter 10 (bn)
M-10E), charged for 1 minute, and measured the volume resistance value.

(6) Appearance of cured product The molded product was visually observed.

(7) Temperature and humidity cycle test (refer to JIS C-5024) A sheet-shaped molded product (1 I x 2005 m x 20 (hm)) was installed in an open room where temperature and humidity could be controlled, and the temperature specified in Table 2 below was set. A temperature/humidity cycle test consisting of 10 cycles was conducted (dump heat cycle test), with one cycle being treated under humidity conditions for 24 hours.
.

Margin No. 2 below: 1 cycle of 7 [cross] lines (8) Tensile test after temperature/humidity cycle test After temperature/humidity cycle test, cure at room temperature (25°C) for 1 day, and follow the procedure described in (4) above. A tensile test was actually carried out.

(9) Change in appearance after temperature/humidity cycle test After the temperature/humidity cycle test, changes in the appearance of the samples were visually observed.

As is clear from the results in Table 3, the epoxy resin compositions (Examples 1 to 7) according to the present invention harden quickly in a room and form a low stress and flexible cured product. Summer. Moreover, after compression, it recovered within several seconds to several tens of seconds and exhibited good rubber-like elasticity. On the other hand, the cured products from the compositions of Comparative Examples 1 to 7 were
Test pieces that were destroyed during compression (Comparative Examples 4, 5.7), or semi-permanently distorted with the side surfaces of the test pieces left open after compression (Comparative Examples 1, 2, 3, 6), etc. It did not exhibit rubber-like elasticity.

In addition, in terms of physical properties after the temperature and humidity cycle test, the examples of the present invention showed little change in strength before and after the test, whereas
The comparative example caused extreme strength deterioration.

Furthermore, the cured products of the examples of the present invention did not lose their flexibility even at low temperatures (0°C), and did not break when subjected to a Dynstat impact test (manufactured by Toyo Seiki Seisakusho ■) at this temperature.
Although it bent and quickly recovered, the cured product of the comparative example
It was destroyed because it became hard and brittle at low temperatures.

Margin below

Claims (1)

[Claims] A room temperature curable epoxy resin composition comprising a flexible epoxy resin, a polythiol compound curing agent, and an amine or phenol curing catalyst.