JPH0221407B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an epoxy resin curing agent. More specifically, polyamines (A) whose main component is a polyamine compound obtained by the reaction of metaxylylene diamine and epichlorohydrin
This invention relates to an epoxy resin curing agent containing an adduct of epoxy compound (B) and epoxy compound (B). Conventionally, various polyamine compounds have been widely used as epoxy resin curing agents, and it is well known that each has unique characteristics due to reactivity with amino groups, that is, active hydrogen. However, these polyamines have strong toxicity such as skin damage, and their cured products may cause whitening due to absorption of carbon dioxide gas in the atmosphere, so they are used in their original form as epoxy resin curing agents. It is rarely used as an epoxy resin curing agent after adding appropriate modification to each polyamine compound. Among these polyamines, when xylylene diamine, especially meta-xylylene diamine, is used as an epoxy resin curing agent, it is suitable for low temperature curing and cures quickly, compared to when aliphatic amines are used. The material has characteristics such as being shiny, having high hardness, and having excellent chemical resistance. However, this curing agent and its cured product suffer from a whitening phenomenon caused by the absorption of carbon dioxide gas in the atmosphere, and the cured product is hard and inflexible, and has drawbacks such as poor adhesion and impact resistance. are doing. Although these drawbacks of meta-xylylene diamine can be improved by various modification methods, none of them can achieve sufficient performance. The present inventors have conducted intensive research to find an epoxy resin curing agent that improves the above-mentioned drawbacks when metaxylylene diamine or its modified product is used as an epoxy resin curing agent. An adduct obtained by reacting an epoxy compound with a polyamine compound, which is a product, and optionally with a polyamine, which is a mixture of this polyamine compound and other amine compounds as a main component, is a curing agent for epoxy resin. The present invention was achieved by discovering that this material exhibits excellent performance. That is, the present invention provides the general formula () obtained by reacting metaxylylene diamine and epichlorohydrin. (In the formula, n is the number of repeating units and represents an integer of 1 or 2) It is a resin curing agent. The polyamine (A) used as a raw material for the curing agent of the present invention has the above formula () obtained by reacting metaxylylene diamine and epichlorohydrin.
It includes a single polyamine compound represented by the above formula (), and a mixture of this polyamine compound and other amines having the polyamine compound represented by the above formula () as a main component. Other amines that can be used in combination include aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine,
Hexamethylene diamine, etc.; aromatic diamine,
For example, phenylene diamine, diaminodiphenylmethane, diaminodiphenylsulfone, etc.; aliphatic amines with an aromatic ring, such as xylylene diamine; cycloaliphatic amines, such as isophorone diamine, menthanediamine, bisaminomethylcyclohexane, etc. I can do it.
Among these, metaxylylene diamine is particularly preferred. The polyamine compound represented by the above general formula (), which is a reaction product of meta-xylylene diamine and epichlorohydrin, has the value of n in the general formula changed by changing the reaction molar ratio of meta-xylylene diamine and epichlorohydrin. I can do it. Even if the value of n is larger than 2, it will not greatly affect the curing characteristics after adding the epoxy compound, but the viscosity of the adduct will increase, which is unfavorable in terms of workability of the curing reaction. 2 or less is better. Here, the value of n means that it is 2 or less as an average value, and to that extent, even if the polyamine compound represented by formula () contains a compound whose value of n is 2 or more. good. The epoxy compound (B), which is the other raw material of the curing agent of the present invention, specifically includes monoepoxy compounds and diepoxy compounds, but is not limited thereto. As monoepoxy compounds, glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, etc.; glycidyl esters such as glycidyl butyrate, glycidyl laurate, glycidyl methacrylate; alkylene oxides, such as Ethylene oxide, propylene oxide, butylene oxide, etc.; Monoepoxy compounds with aromatic rings, such as styrene oxide; Epihalohydrins, such as,
Examples include epichlorohydrin and the like; alicyclic epoxy compounds such as cyclohexene oxide. Typical diepoxy compounds include glycidyl compounds such as polyhydric alcohols, polyhydric phenols, polycarboxylic acids, and polyhydric amines, and non-glycidylated diepoxy compounds can also be used. In producing the adduct of the polyamine (A) and epoxy compound (B) of the present invention, the polyamine (A)
The reaction ratio between epoxy compound (B) and epoxy compound (B) does not need to be particularly limited as long as the resulting adduct contains an amino group with active hydrogen, but if the amount of epoxy compound used is small, , a decrease in performance is seen in the cured epoxy resin products using the adducts produced, and conversely, when the amount of epoxy compound used is large, the viscosity of the adducts produced increases, and the viscosity of the adducts produced using it increases. Chemical resistance of cured epoxy resin products decreases. The reaction ratio between polyamines (A) and epoxy compound (B) takes into account the properties of the above-mentioned addition product and the performance of the cured product, and also takes into account the shape of the polyamine compound of the present invention, the type of epoxy compound, and the solvent. Alternatively, it may be determined in consideration of various factors such as the use of a diluent, and cannot be determined uniquely. The curing agent of the present invention is generally produced by keeping polyamines at a predetermined temperature and dropping an epoxy compound under stirring to cause a reaction. The conditions for this reaction may be substantially the same as those for conventional production of adducts of polyamine compounds and epoxy compounds. Specifically, the reaction temperature is 50 to 150°C, and the reaction time is 1 to 5 hours. be selected appropriately. As the epoxy resin to be cured using the adduct of the present invention, a known one can be used. These epoxy resins have at least two epoxy groups per molecule, and include glycidyl-type epoxy resins and non-glycidyl-type epoxy resins, which are glycidyl compounds such as polyhydric alcohols, polyhydric phenols, polyhydric carboxylic acids, or polyhydric amines. It is resin. The compounding ratio of the curing agent and epoxy resin of the present invention is:
It is usually determined by the ratio between the active hydrogen equivalent of the curing agent of the present invention and the epoxy equivalent of the epoxy resin. There is no need to limit it. Upon curing, various additives such as diluents, fillers, pigments, etc. may be added if desired. The curing agent of the present invention has good compatibility with epoxy resins, and the cured epoxy resin products cured using this curing agent have good transparency and gloss, are highly flexible, and have strong adhesive properties. It exhibits a variety of excellent properties, including high hollow strength, impact resistance, and good chemical resistance. EXAMPLES Below, in order to further clarify the features of the curing agent of the present invention, Examples will be specifically described. Examples 1 to 14 A predetermined amount of the polyamines shown in Table 1 was charged into a reaction vessel equipped with a stirring device, a thermometer, a nitrogen inlet tube, a dropping funnel, and a condenser, and the predetermined amount shown in Table 1 was heated at 80°C with stirring. Drop the epoxy compound of
The reaction was carried out at 100°C for 3 hours in a nitrogen atmosphere to obtain an adduct of polyamines and epoxy compounds. These adducts were diluted to a predetermined concentration using a 1:1 (weight ratio) mixed solvent of xylene and ethylene glycol monoethyl ether, and their amine values and viscosity were measured. These results are shown in Table 1. These additives were blended into an epoxy resin [trade name "Epicoat #1001-X-75", manufactured by Yuka Ciel Epoxy Co., Ltd.] in the amounts shown in Table 2, and this was applied to a cold-rolled steel plate as a 200μ film. It was applied thickly and cured at 20°C for 7 days. The physical properties of the cured film were measured. The results are shown in Table 2, and the results of the chemical resistance test are shown in Table 3.

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Claims (1)

[Claims] 1 General formula obtained by reacting metaxylylene diamine and epichlorohydrin (In the formula, n is the number of repeating units and is an integer of 1 or 2) Resin hardener.