JPH0339100B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has excellent weather resistance, flexibility, adhesion,
The present invention relates to a method for producing a solid epoxy resin having good properties such as boiling water resistance. Epoxy resins are used in various applications such as paints, electricity, civil construction, and adhesives due to their excellent performance, and are particularly used in paints. In paint applications, the demand for powder paints has been increasing in recent years due to the increasing need for low pollution and resource conservation. This powder coating is usually obtained by heating resin components, pigments, and other additives, melting and kneading them using an extruder, etc., and then cooling and pulverizing the resulting solid material. Therefore, the resin components used are:
Resins that have good blocking resistance and low melt viscosity at storage temperatures (usually room temperature) are desirable. Currently, epoxy resin, polyester, and acrylic resin are the three major resin components for powder coatings, but conventional epoxy resins have drawbacks such as weather resistance, flexibility, boiling water resistance, and pigment dispersion. There are various problems in practical use. Up to now, various attempts have been made to improve the drawbacks of conventional epoxy resins. Among them, JP-A-50-22897 and JP-A-50-153097.
The publication states that the use of a reaction product of hydrogenated bisphenol A diglycidyl ether and a carboxylic acid-containing compound significantly improves weather resistance, but our follow-up tests showed that flexibility It was confirmed that this was completely inadequate and difficult in practice. The present inventors have arrived at the present invention as a result of various studies on methods for improving the drawbacks of these conventional epoxy resins and obtaining an epoxy resin composition that satisfies both weather resistance and flexibility. be. That is, the present invention provides (a) 100 parts by weight of hydrogenated bisphenol diglycidyl ether, (b) 10 to 60 parts by weight of aromatic dicarboxylic acid or alicyclic dicarboxylic acid, and (c) carbon number 12 to 20. aliphatic dicarboxylic acid of 15
The present invention relates to a method for producing a solid resin with good weather resistance, characterized by reacting up to 100 parts by weight of the solid resin. The diglycidyl ether of hydrogenated bisphenol used in the present invention is, for example, hydrogenated 2,
Diglycidyl ethers such as 2'-bis(4,4'-hydroxyphenyl)propane, hydrogenated bis(4,4'-hydroxyphenyl)methane, hydrogenated bis(4,4'-hydroxyphenyl)sulfone, etc. can be mentioned. Aromatic dicarboxylic acids used in the present invention include, for example, phthalic acid, isophthalic acid, terephthalic acid,
as well as the expression (However, in the formula, Z is (-CH ₂ ) _-o n; 1 to 6, -S
−、

【formula】

[Formula] or -O-), for example, bis(4,
4'-carboxylphenyl)methane, bis(4,
Mention may be made of 4'-carboxylphenyl) ether. Examples of the alicyclic dicarboxylic acids used in the present invention include hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, bromohexahydrophthalic acid, and methylhexahydroterephthalic acid. The aliphatic dicarboxylic acid having 12 to 20 carbon atoms used in the present invention is, for example, dodecanedicarboxylic acid,
Examples include dodecanedicarboxylic acid, undecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, 2-methyldodecanedicarboxylic acid, and the like. Incidentally, if the number of carbon atoms is 11 or less, flexibility is insufficient, and if the number of carbon atoms is 21 or more, chemical resistance and surface hardness are low. The composition obtained by the method of the present invention contains diglycidyl ether of hydrogenated bisphenol in about
aromatic compound in the presence of a catalyst such as a tertiary amine, quaternary ammonium salt, quaternary phosphonium salt, etc. at a temperature of 80 to 200° C. for a sufficient period of time to form the product, usually from about 1 to about 30 hours. Alternatively, it can be easily obtained by reacting an alicyclic dicarboxylic acid and an aliphatic dicarboxylic acid having 12 to 20 carbon atoms. The composition of the present invention has a softening temperature of 60 to 200°C.
As a resin for powder coatings, it is practically within the range of
A range of 70 to 100°C is preferred. In the present invention, the curing agent is not particularly limited, and commonly used curing agents can be used. For example, novolak type phenolic resin, dicyandiamide, imidazoles, hydrazides, aromatic amines, acid anhydrides, etc. can be used. A coating film using an epoxy resin obtained by the present invention exhibits good weather resistance and flexibility, and also has good water resistance, acid resistance, and alkali resistance. The use of the resin composition obtained by the present invention is not particularly limited, and can be applied to a wide range of uses such as external coating of steel pipes, coating of steel bars, and electrical insulation coatings. Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, unless otherwise specified, parts represent parts by weight. Examples 1-4 Diglycidyl ether of hydrogenated bisphenol A (HBADGE) with epoxy equivalent weight 240
An aromatic dicarboxylic acid and an aliphatic dicarboxylic acid having 12 to 20 carbon atoms, or an alicyclic dicarboxylic acid and a carbon number
Add 12-20 aliphatic dicarboxylic acids and methyltriphenylphosphonium iodide as a catalyst at 140°C.
The reaction was carried out for about 1 to 8 hours. The reaction results are shown in Table-1.

[Table] Examples 5 to 8 After kneading trimellitic anhydride as a curing agent, TiO ₂ and a flow control agent in Examples 1 to 4 using a kneader at a temperature of 120°C in the screw part and 130°C in the die part,
A powder coating was obtained by grinding at room temperature. This powder coating was applied to a mild steel plate using an electrostatic coating machine and baked at 190°C for 20 minutes to examine coating performance. The results are shown in Table 2 (film thickness is 100 microns).

[Table] Comparative Example 1 Epoxy resin A obtained by reacting in the same manner as in Example 1 using adipic acid instead of octadodecanedicarboxylic acid (epoxy equivalent: 1400, Duran softening point: 89~ 94℃),
The coating film performance was investigated in the same manner as in Example 5 (film thickness
100 microns). Compound Epoxy Resin A 100 parts Trimellitic anhydride 8 TiO ₂ 25 Flow control agent 1 Coating film performance Erichsen 3mm Dupont impact value (500g, 1/2 inch) 10cm Adhesion 100/100 Bendability 6mmφ passed Example 9 To 100 parts of the resin of Example 1, 5 parts of dicyandiamide and 0.2 parts of 2-methylimidazole were added as a curing agent.
25 parts of TiO ₂ and 1 part of a flow control agent were kneaded in a kneader under the same conditions as in Example 1, and pulverized to obtain a powder coating. This paint was applied at 180°C in the same manner as in Example 5.
After baking for 20 minutes, the gloss retention rate was examined using a sunshine weather meter. Gloss retention rate (%) After 100 hours 95 300 〃 90 500 〃 80 Comparative example 2 In Example 9, the resin of Example 1 was replaced with bisphenol A type epoxy resin AER-664P (manufactured by Asahi Kasei Corporation) with an epoxy equivalent of 950. The gloss retention rate was examined in the same manner as in Example 9. Compound AER-664P 100 parts Dicyandiamide 5〃 2-Methylimidazole 0.2〃 TiO ₂ 25〃 Flow control agent 1〃 Gloss retention (%) After 100 hours 80 300 〃 15 (Surface yellowing) 500 〃 Not measured

Claims (1)

[Scope of Claims] 1 (a) Based on 100 parts by weight of hydrogenated diglycidyl ether of bisphenol, (b) aromatic dicarboxylic acid or alicyclic dicarboxylic acid
10 to 60 parts by weight and (c) 15 to 100 aliphatic dicarboxylic acid having 12 to 20 carbon atoms
A method for producing a solid resin with good weather resistance, characterized by reacting parts by weight.