JPS6243454B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solvent-free or high-solids curable epoxy resin composition, which is curable at room temperature and is useful for two-component paint vehicles, adhesives, molding materials, and the like. Amine-based epoxy curing agents such as polyamide, polyamide adduct, and amine adduct are used as curing agents for room-temperature curable epoxy resin paints on ships, bridges,
It is widely used as a heavy duty anti-corrosion coating for objects exposed to harsh conditions such as offshore structures. Currently, amine-based curing agents with a relatively high molecular weight and a non-volatile content of about 60% to 70% are used as epoxy resin curing agents, and paints contain large amounts of organic solvents, resulting in air pollution and resource conservation. This has become a big problem, and there is a strong demand for solvent-free or high-solids products. For this reason, the development of solvent-free or high-solids amine-based hardeners is being actively conducted, but in general, the use of solvent-free or high-solids amine hardeners results in inferior corrosion protection performance and insufficient pot life. Practical use is limited by problems such as slow curing time, poor water resistance, and strong toxicity due to free amines. In view of the above circumstances, the present inventors have conducted various studies in order to develop a solvent-free or high-solids type amine-based epoxy resin curing agent that has low toxicity and exhibits good anticorrosion performance over a long period of time. The present invention has now been accomplished. According to the present invention, it is obtained by reacting a monobasic unsaturated fatty acid (a), a polyamine (b), and optionally a modifier (c), and the component (a) accounts for 20 to 90% by weight. , and an amide-based epoxy curing agent (A) with an iodine value of 40 or more, an epoxy resin (B), and the weight of the sum of (A) and (B).
A curable epoxy resin composition containing 0.1 to 10% by weight of a metal dryer (C) as an essential component is provided. Examples of the monobasic unsaturated fatty acid (a) used as a raw material for the curing agent (A) include coconut oil, castor oil, cottonseed oil, dehydrated castor oil, linseed oil, oiticica oil, edible oil, and safflower oil. Natural fatty acids obtained from oil, sardine oil, soybean oil, tall oil, tung oil, rice bran oil, etc., among others, are obtained from edible oil, linseed oil, dehydrated castor oil, tall oil, and sardine oil, which have a high iodine value. Preferably. Other expensive monobasic unsaturated fatty acids such as linoleic acid, linolenic acid, oleic acid, and eleostearic acid can also be used. Polyamines (b) include polyethylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine, xylylenediamine, and tolylenediamine, which are used as raw materials for ordinary amide curing agents. Aromatic polyamines such as , phenylene diamine, diaminodiphenylmethane, and heterocyclic diamines can be used. In addition, monobasic unsaturated fatty acids (a) and polyamines (b)
The modifier (c) may be reacted with the polyamine (b) prior to the reaction with the polyamine (b), or the modifier (c) may be reacted during or after the reaction of (a) and (b). Such modifiers (c) include, for example, ethylene oxide,
Low molecular weight epoxides such as propylene oxide, butyl glycidyl ether, versatile acid glycidyl ester, phenyl glycidyl ether, allyl glycidyl ether; obtained by the reaction of bisphenol A, bisphenol S, bisphenol F, novolak or glycerin with epihalohydrin. Typical examples include various epoxy resins; or dimer acids and acrylonitrile. The reaction ratio of monobasic unsaturated fatty acid (a), polyamine (b), and optionally modifier (c) is such that component (a) accounts for 20 to 90% by weight of the total and the reaction product Select so that the iodine value is 40 or more and the amine value is 80 to 350. Epoxy resin used in the resin composition of the present invention
(B) is not particularly limited as long as it is liquid at room temperature and has two or more epoxy groups. Examples of such materials include Epibis type epoxy resins obtained by the reaction of bisphenol A and epichlorohydrin, novolak type epoxy resins obtained by the reaction of phenol resins and epichlorohydrin, and double bond moieties of polybutadiene. Polybutadiene type epoxy compound epoxidized with peracetic acid etc., halogenated bisphenol A, bisphenol S or bisphenol F
and epichlorohydrin, polyalkylene ether type epoxy resins obtained by reacting glycols such as polyethylene glycol and polypropylene glycol with epichlorohydrin, β-methylepichlorohydrin and polyhydric phenols, and polyhydric alcohols. Alternatively, examples thereof include methyl-substituted epoxy resins obtained by reaction with polyhydric carboxylic acids, other urethane-modified epoxy resins, copolymers of vinyl compounds having epoxy groups such as glycicyl methacrylate, and mixtures thereof. In addition, the epoxy resin (B) includes butyl glycidyl ether, phenyl glycidyl ether, m-
Alternatively, a monoepoxy compound such as p-cresol glycidyl ether may also be used in combination. In addition, it is preferable to use bisphenol A type or F type epoxy resin with an epoxy equivalent of 170 to 500 in the formulation of high solids type anticorrosive paints.
Examples include Epicron 1050, Epicron 850, Epicron 855, and Epicron 830. The curing agent (A) and the epoxy resin (B) are used in such a ratio that the ratio of theoretically active hydrogen atoms to epoxy groups is 1/1 to 0.8/1. Next, the metal dryer (C) used as another component of the composition of the present invention is, for example, a naphthenate or octylate of lead, cobalt, manganese, calcium, zinc, copper, zirconium, cerium, iron, etc. , tall oil fatty acid salts or synthetic acid salts are used. Although a single dryer is effective, two dryers, such as a combination of lead naphthenate and cobalt naphthenate, are usually used.
It is preferable to use more than one species in combination. The amount of this metal dryer added is 0.1 to 10% by weight, preferably 1 to 3% by weight, based on the total solid content of the curing agent (A) and the epoxy resin (B). Drying speed can be adjusted. The composition of the present invention may also contain solvents, catalysts, fillers, pigments, and other additives as necessary depending on the intended use. The composition of the present invention has a low viscosity (usually less than 20,000 cps at room temperature) without the use of a solvent, requires very little solvent, and dries quickly, making it suitable for conventional epoxy resin applications. For example, it is suitably used as a solvent-free or high-solids material in paints, adhesives, and molding materials. In particular, the composition of the present invention is useful as a paint vehicle, and can provide a coating film with excellent gloss and adhesion without blooming or brushing when applied with a brush or spray, and can be applied thickly in one go. Good workability. The composition of the present invention is also useful as a tar epoxy resin paint when used in combination with tar, and as a solvent-free or high solids type epoxy paint with excellent long-term corrosion resistance, the coating film has good chemical resistance, flexibility, and adhesion. It shows excellent physical properties such as corrosion resistance. In addition, the composition of the present invention has characteristics such as low toxicity, quick drying even at room temperature, and a sufficiently long pot life. Next, the present invention will be explained in more detail with reference to Synthesis Examples and Examples. Note that "parts" are based on weight. Synthesis Example 1 Synthesis of Polyamide A Dehydrated castor oil fatty acid to 73 parts of triethylenetetramine and 95 parts of tetraethylenepentamine
Add 424 parts and heat to 250℃ over 3 hours.
The dehydration amidation reaction was carried out at the same temperature for 6 hours. Thus, Gardner viscosity Z ₁ −Z ₂ , amine value
208, a polyamide with an iodine value of 90 was obtained. Synthesis Example 2 Synthesis of Polyamide B 280 parts of rice bran oil fatty acid and 105 parts of coconut oil fatty acid were added to 73 parts of triethylenetetramine and 95 parts of tetraethylenepentamine, and the mixture was heated to 250 parts over 3 hours.
The mixture was heated to 0.degree. C., and dehydration and amidation reaction was carried out at the same temperature for 6 hours. In this way, a polyamide having a Gardner viscosity Z, an amine value of 210, and an iodine value of 24 was obtained. Synthesis Example 3 Synthesis of Polyamide C 325 parts of linseed oil fatty acid was added to 146 parts of triethylenetetramine, heated to 250°C over 3 hours, and dehydrated and amidated at the same temperature for 6 hours. After the amidation reaction, the temperature is lowered and the “Epicron”
850'' (epoxy equivalent: 190, bisphenol type epoxy resin: manufactured by Dainippon Ink & Chemicals Co., Ltd.) was added, and the reaction was carried out at 120°C for 2 hours. As a result, Gardner viscosity Z ₄ and amine value
230 and an iodinated polyamide of 83 was obtained. Synthesis Example 4 Synthesis of Polyamide D 54 parts of "Epiclon 830" (epoxy equivalent: 180, bisphenol type epoxy resin: manufactured by Dainippon Ink & Chemicals Co., Ltd.) was added to 102 parts of triethylenetetramine and 13 parts of xylylene diamine. The reaction was carried out at 120°C for 2 hours. Thereafter, 273 parts of dehydrated castor oil fatty acid and 69 parts of dimer acid were added, and the temperature was raised to 250°C over 3 hours, followed by dehydration and amidation reaction at the same temperature for 5 hours. In this way, a polyamide having a Gardner viscosity of Z ₃ , an amine value of 250, and an iodine content of 64 was obtained. Synthesis Example 5 Synthesis of Polyamide E Add 325 parts of linseed oil fatty acid to 80 parts of pentaethylenehexamine and 44 parts of triethylenetetramine.
The temperature was raised to 250°C over 3 hours, and dehydration and amidation reaction was carried out at the same temperature for 6 hours. After the amidation reaction was completed, the temperature was lowered, 38 parts of "Epicron 850" was added, and 120 parts of
The reaction was carried out at ℃ for 2 hours, and the Gardner viscosity Z ₁ - Z ₂ ,
A polyamide with an amine value of 280 and an iodine value of 85 was obtained. Example 1 10 parts of “Epiclon 1050” (epoxy equivalent: 450; bisphenol type epoxy resin; manufactured by Dainippon Ink & Chemicals Co., Ltd.), “Epiclon 850” (epoxy equivalent: 190; bisphenol type epoxy resin; Dainippon Ink & Chemicals Co., Ltd.) Co., Ltd.) and 4 parts of toluene, 58 parts of polyamide A or B and 1.5 parts of cobalt naphthenate and 1.5 parts of lead naphthenate as metal dryers were added, and after thorough mixing, a mild steel plate was prepared. Brush on top
A thick film of 150 microns was applied, left for one week at room temperature, drying properties were examined, and the resulting cured coating was tested for physical properties. The results are shown in Table 1 below.

[Coating film test method]

ΓDrying properties ●Finger touch: When you touch the paint film with your finger, the time until it loses its tackiness ●Curing: Even if you press the paint film with your finger, there will be no dents or uneven fingerprints. Time until summer

【table】

Claims (1)

[Claims] 1 Monobasic unsaturated fatty acids as an essential ingredient
Component (a) obtained by reacting polyamine (b) and, if necessary, a modifier (c), contains 20 to 90% by weight of the component (a).
an amide-based epoxy curing agent (A) that occupies a range of
A solvent-free or high-solids curable epoxy resin composition further comprising 0.1 to 10% by weight of a metal dryer (C) based on the total amount of these components (A) and (B).