JP3009194B2 - Curing agent for epoxy resin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a curing agent for epoxy resins, and a coating composition and an adhesive composition containing the same.

[Conventional technology]

BACKGROUND ART Conventionally, aliphatic polyamines have been used as epoxy resin curing agents because they have relatively good curing performance and are easy to handle.

[Problems to be solved by the invention]

However, it has an unpleasant odor, has strong skin toxicity, and causes amine brushing when it is applied as a coating film.Therefore, it is rarely used as it is. A modified amine-based curing agent to which a compound has been added is used.

A cured epoxy resin product using these materials does not have sufficient adhesiveness and water resistance, and often causes stickiness on the surface of the cured product.

As another modified amine-based curing agent, Japanese Patent Publication No. 50-1600
Japanese Patent Application Laid-Open Publication No. H11-157,897 describes a product obtained by adding a polyglycidyl ether of a polyphenol and an alicyclic amine, but these have a high viscosity and are not easy to handle, and the flexibility of the cured product is also insufficient. is there.

Furthermore, curing agents in which a monoepoxy compound is added to an aromatic amine are also being studied, but these have poor stability at low temperatures and cause crystallization phenomena, and the surface of a cured product with an epoxy resin turns yellow. Easy and lacks flexibility.

[Means for solving the problem]

The present inventors have conducted various studies in order to solve these problems of the modified amine-based epoxy resin curing agent, and as a result, have completed the present invention.

That is, the present invention is obtained by reacting bicycloheptanediaminomethyl or an amine mixture containing the same with a monoglycidyl ether compound in a ratio of 0.1 to 0.95 equivalents of the monoglycidyl ether compound to 1 active hydrogen equivalent of the amine. The present invention relates to a curing agent for an epoxy resin, characterized by containing an added product, and a coating composition and an adhesive composition containing the same.

The curing agent of the present invention has low viscosity and low odor. In addition, when cured with an epoxy resin, it has excellent adhesion and water resistance, and has little yellowing when exposed to sunlight or the like.

Examples of the bicycloheptanediaminomethyl used in the present invention include, for example, 2,5-endo, exo-bicycloheptanediaminomethyl, 2,6-endo, exo-bicycloheptanediaminomethyl, 2,5-diexo-bicycloheptanediaminomethyl , 2,6-diexo-bicycloheptanediaminomethyl and mixtures thereof.

Bicycloheptanediaminomethyl may be a mixture of this with another amine, and in this case, the amine may be ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, tetramethylenediamine, hexamethylenediamine. Aliphatic polyamines such as diamines, aliphatic monoamines such as ethyleneamine, propyleneamine, butylamine, laurylamine and octylamine; polyamines having aromatics such as xylylenediamine; alicyclic polyamines such as isophoronediamine and diaminocyclohexane; And aromatic polyamines such as phenylenediamine and 4,4'-diaminodiphenylmethane.

Preferred among these are aliphatic polyamines.

When a mixture of bicycloheptanediaminomethyl and another amine is used, the content of bicycloheptanediaminomethyl is usually at least 20% by weight, preferably at least 50% by weight, based on the amount of the mixture.

Examples of the monoglycidyl ether compound used in the present invention include monoglycidyl ethers such as allyl glycidyl ether, phenyl glycidyl ether, and butyl glycidyl ether, and mixtures thereof.

Of these, particularly preferred are phenyl glycidyl ether and butyl glycidyl ether.

In the reaction between bicycloheptanediaminomethyl or an amine mixture containing the same and the monoglycidyl ether compound, the reaction ratio between the two may be any ratio such that the obtained adduct has active amino hydrogen, and bicycloheptanediaminomethyl or The monoglycidyl ether compound is generally used in an amount of 0.1 to 0.95 equivalent, preferably 0.2 to 0.7 equivalent, per one active amino hydrogen equivalent of the amine mixture containing the same.

When the amount of the monoglycidyl ether compound is less than 0.1 equivalent, the flexibility and adhesiveness of the epoxy resin cured with the adduct are practically unsatisfactory.

For example, when 1 mol of bicycloheptanediaminomethyl and 1 mol of butyl glycidyl ether are reacted, about 60% by weight of the reaction product is modified. Unless modified to this extent, the properties of bicycloheptanediaminomethyl as a curing agent cannot be improved.

Further, when the monoglycidyl ether compound exceeds 0.95 equivalent, disadvantages such as a considerably high viscosity and a decrease in water resistance and chemical resistance of the cured product appear, which are not preferable.

In order to obtain the curing agent of the present invention, for example, a monoglycidyl ether compound is blown or dropped into bicycloheptanediaminomethyl or an amine mixture containing the same to react.

The reaction temperature is generally 0-250 ° C, preferably 20-150 ° C. The reaction time is usually 1 to 5 hours.

The epoxy resin that uses the adduct obtained by the above reaction as a curing agent may be a conventional epoxy resin. Type epoxy resin, alicyclic epoxy resin, polyglycidyl ether of polyhydric alcohol.

The amount of the curing agent of the present invention to be added to the epoxy resin is such that the epoxy group in the epoxy resin is usually 0.5 to 1.5 per amino hydrogen atom of the present curing agent.

In use, any of a method of mixing the resin and the curing agent as they are, a method of mixing in the presence of a solvent, and a method of mixing in an emulsified state can be used. Curing can be performed by any of ordinary temperature and heating methods.

The curing agent of the present invention may be used in combination with other known curing agents, for example, a polyamide resin or an aliphatic polyamine. In this case, the content of the adduct in the present invention is usually 20% by weight of the total curing agent. That is all.

Other known curing agents include polyamidoamines; aliphatic polyamines, polyamines having aromatic rings, alicyclic polyamines, aromatic polyamines and the like, modified products of polyamines other than monoepoxy compounds, for example, polyamines and phenols Are condensed with formalin.

The adduct in the present invention may be used in admixture with an adduct of a polyamine other than bicycloheptanediaminomethyl and a monoepoxy compound, or an unmodified polyamine.

The curing agent of the present invention may be used by adding a curing accelerator such as a phenol or a tertiary amine or an auxiliary such as a pigment, a filler, a bulking agent or a reinforcing agent.

The present invention relates to a curing agent for an epoxy resin containing an adduct of bicycloheptanediaminomethyl or an amine mixture containing the same and a monoglycidyl ether compound, but instead of the above adduct, bicycloheptane When diaminomethyl is used alone as a curing agent for an epoxy resin, the curing is slow, so that its performance is not exhibited at all at room temperature and the adhesiveness and flexibility are poor.

The curing agent of the present invention has low viscosity (25 ° C.) at room temperature (for example, 100 to 5,000 cps), low skin toxicity, good compatibility with epoxy resin, and low heat generation during mixing.

The epoxy resin cured product cured using this curing agent has good water resistance and adhesiveness, and is particularly excellent in yellowing as compared with the case using a conventional curing agent.

The curing agent of the present invention is used together with an epoxy resin,
It is important as a curing agent for paints and epoxy resins for civil engineering, but can also be used for applications such as adhesives, casting resins, and laminates.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

In the following, parts are by weight unless otherwise specified.

Tables 1 and 2 summarize the test results of the examples and the comparative examples.

Examples 1 to 6, Comparative Examples 1 to 6 A predetermined amount of an amine component was charged into a four-necked flask equipped with a stirrer, a thermometer, a separator equipped with a condenser and a nitrogen inlet tube, and heated to a temperature of 60 to 150 ° C. The monoepoxy compound was dropped or blown, and reacted at the same temperature under a nitrogen atmosphere for 1 to 5 hours to obtain the curing agents of Examples 1 to 6. When the reaction was completed, the reaction mixture was cooled to obtain a reaction product (curing agent of the present invention).

Further, the curing agent obtained in Example 1 has an amine value of 380
Example 7 was a curing agent obtained by mixing the polyamide curing agent (Tomide 235S; manufactured by Fuji Kasei Kogyo) at a ratio of 1: 1 (weight ratio).

About this reaction product, amine odor and viscosity were measured,
Epoxy resin (Epicoat)
828; epoxy equivalent 190, oil-based gel epoxy product), and the cured physical properties (coating film appearance, adhesion, water resistance and flexibility) were measured. For comparison, the cured physical properties of a conventional curing agent were also measured.

 The results are shown in the table.

〔The invention's effect〕

The curing agent of the present invention has a low viscosity (25 ° C.) at room temperature, has almost no amine odor, has good compatibility with an epoxy resin, and is a cured product of an adhesive and a coating composition containing the same. It is clear from Table 2 that each of these has excellent adhesiveness, water resistance and coating film appearance.

Claims (3)

(57) [Claims] 1. A monoglycidyl ether compound obtained by reacting bicycloheptanediaminomethyl or an amine mixture containing the same with a monoglycidyl ether compound in a ratio of 0.1 to 0.95 equivalents of the monoglycidyl ether compound per one active hydrogen equivalent of the amine. A curing agent for an epoxy resin, characterized in that the curing agent contains an additive. 2. A coating composition comprising the epoxy resin curing agent according to claim 1 and an epoxy resin. 3. An adhesive composition comprising the epoxy resin curing agent according to claim 1 and an epoxy resin.