JPS6259620A - Curable resin - Google Patents

Abstract

PURPOSE:To prepare the titled low-odor resin excellent in rapid curability and film properties, by reacting a phenolic resin obtained from an alkenylphenol and an aldehyde with an alkylene oxide or an alkylene carbonate. CONSTITUTION:A phenolic resin (A) is obtained by (co)condensing an alkenylphenol (a) (e.g., cashew nutshell liquid) with 0.5-1.2mol, per mol of component (a), of an aldehyde (b) (e.g., formalin) and, optionally, a phenol (c) in the presence of an acid or alkali catalyst (e.g., HCl). Component A is reacted by an addition reaction with 1.0-2.0mol, per mol of component A, of an alkylene oxide or an alkylene carbonate (e.g., ethylene oxide) in the presence of, optionally, an alkali catalyst (e.g., KOH) to obtain a curable resin having repeating units of formula I (wherein R1 is a group of any one of formulas II-V, R2 is H or -OR1, R3 is a 3-17 C unsaturated hydrocarbon group having 1-3 double bonds and n is 3-500).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a curable resin, and more particularly to a curable resin that is cured by a crosslinking agent and a metal dryer and provides good physical properties of a coating film.

[Technical background and its! ', 'Tg point]

Conventionally, paints using resins prepared from alkenylphenols have been cured by oxidative polymerization under the catalytic action of a metal dryer or the like. Such paints have excellent properties such as good workability, the ability to be applied thickly, a cured film with high gloss and uniform hardness, and an elegant coating surface with excellent durability.

However, since the cured coating film is formed only by oxidative polymerization, the internal curing speed is slow, and there are also problems in that an unpleasant odor is generated, which is thought to be caused by low-molecular aldehydes, etc., which are by-products of oxidation. . Therefore, its uses are limited and it is only used in specific industries.

[Purpose of the invention]

An object of the present invention is to provide a curable resin that provides fast curing properties, reduces odors, etc., and has excellent coating film properties without sacrificing any of the advantages of conventional alkenylphenol resin coatings.

[Summary of the invention]

The present inventors have discovered that these objects can be achieved by introducing an alcoholic hydroxyl group into an alkenylphenol resin, and using a metal dryer and a steel wire that is reactive with the hydroxyl group, leading to the present invention.

The curable resin of the present invention has the following formula: (wherein, R1 is -CHz-CHz-OH1 to CHz-C
H-OH.

CH3 -CHz-CHz-0-CHz-C)Iz-OH or C
113C) If It may become. R2 represents a hydrogen atom or -OR+, R
3 represents an unsaturated hydrogen oxide group having 1 to 3 double bonds and having 3 to 17 carbon atoms, and n represents an integer of 3 to 500). be.

The above-mentioned curable resin of the present invention can be produced, for example, as follows.

First, a phenol resin is synthesized by condensation-polymerizing alkenylphenol with an aldehyde in the presence of an acid or alkali catalyst. Examples of the alkenylphenol include allylphenol, cardanol, urushiol, etc. Cashew nut shell liquid is particularly desirable from the viewpoint of physical properties since it is produced in large quantities and is therefore advantageous. Further, in order to adjust the hardness of the coating film, etc., phenols such as phenol, cresol, and xylenol can be cocondensed and polymerized, but it is necessary to suppress the amount to 50 mol % or less in order to delay the curing reaction due to oxidation.

The aldehyde used in the condensation polymerization can be selected from formalin, paraformaldehyde, hexamethylenetetramine, and the like. The molar ratio of aldehydes to phenols is 0.5 to 1.2. HCl is used as a catalyst.

H2SO4, NaOH, ZnClz, etc. are selected from those commonly used for phenolic resin synthesis, but in order to control the molecular weight distribution width, H(1!.

ZnC (!□ etc. are excellent.

Next, alkylene oxide or alkylene carbonate is added to the obtained phenol resin, if necessary, with NaOH or K.
An addition reaction is carried out in the presence of an alkali catalyst such as OH, KaCO3, NazCOx, etc. to convert the phenolic water FJ2M into an alcoholic hydroxyl group, which leads to the resin of the present invention. As the alkylene oxide or alkylene carbonate used, ethylene oxide, propylene oxide, ethylene carbonate, and propylene carbonate are preferable from the viewpoint of reactivity. The molar ratio of these compounds to phenols is preferably 160 to 2.0.
If it is too little, the curing will be insufficient, and if it is too much, it will become too flexible.

The molecular weight of the curable resin of the present invention is regulated by the molecular weight of the phenolic resin that is the precursor, but even if the phenolic resin has a low molecular weight, after alcoholization, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, adipine It can be polymerized by esterification with dibasic acids such as acids or by urethanization with isocyanates such as TDI (lylene diisocyanate). In addition, it can be modified with rosin, linseed oil fatty acid, etc. to improve the physical properties of the coating film or the compatibility with other curing agents. After alcoholization, the remaining catalyst is neutralized and precipitated as an inorganic salt, and unreacted substances are distilled off under reduced pressure.Then, the precipitate is separated and purified by diluting with a solvent and passing through a hot filter. A curable resin solution of the invention is obtained.

The resin of the present invention produced in this way undergoes oxidative polymerization using a metal dryer catalyst at the side chain having a double bond, and a crosslinking agent reactive with an alcoholic hydroxyl group, such as an isocyanate resin prepolymer or a urea resin prepolymer. Alternatively, it also has the function of crosslinking with an alcoholic hydroxyl group added to a phenolic hydroxyl group using a melamine resin prepolymer or the like. Thus, unlike conventional alkenylphenol resin paints, it can be cured quickly without relying solely on oxidative polymerization, and has the characteristics of being able to reduce odors and the like caused by oxidative polymerization. In particular, when a metal dryer and an isocyanate resin prepolymer are used in combination, the paint can be cured at room temperature, and the curing time is halved compared to conventional alkenylphenol resin paints. In addition, when block isocyanate resin prepolymer, urea resin prepolymer, and melamine resin prepolymer are used together, it can be made into a one-component product.
Although heat curing is required, a coating film with excellent internal curability, high hardness, and excellent appearance can be obtained.

For example, Co
+ P b + M +1 / Ca + Z r
, Z n + Fe + Al, and salts of metals such as Cu with rosin, oleic acid, linoleic acid, naphthenic acid, tall oil, etc., which can be used alone or in combination. Addition amount is 0.01 as metal amount to resin content
~0.1% by weight, and if it is less than 0.01% by weight, curing will be insufficient, and if it exceeds 0.1% by weight, there will be a lot of odor due to oxidative polymerization, and the purpose of the present invention cannot be achieved. The reaction with the crosslinking agent used in combination, such as an isocyanate resin prepolymer, is excessively promoted, resulting in poor storage stability.

0.03 to 0.06% by weight is desirable.

Examples of the isocyanate resin prepolymer used as a crosslinking agent include Takenate D102゜Takenate D
2'04. Examples of block isocyanate resin prepolymers include Takenate DIION (trade name, manufactured by Narita Pharmaceutical Co., Ltd.), Millionate MR, Coronate HL (trade name, manufactured by Nippon Polyurethane@), and Takenate B80 as a block isocyanate resin prepolymer.
0 (trade name, Takeda Pharmaceutical Co., Ltd.) etc. can be used.

In addition, as a urea resin prepolymer, for example, Melan #1
4 (trade name, manufactured by Hitachi Chemical) and Super Beckamine D
-138-60 (trade name, manufactured by Dainippon Ink@). Furthermore, as a melamine resin prepolymer, for example, Super Beckamine J-820 (trade name, Dainippon Ink ■
) and Tesmin To-5160 (product name, Tokushima Oil @
), etc.

These crosslinking agents are used in an amount of 10 to 50% by weight based on the resin of the present invention, but if it is less than 10% by weight, it is not very effective, and if it is more than 50% by weight, the effects of the present invention such as coating film performance cannot be obtained. 20
~40% by weight is desirable.

The present invention will be described in detail below with reference to Examples.

Example 1 300 parts by weight of Cassini Nando Shell liquid and 15 parts by weight of hexamethylenetetramine were reacted at 130°C for 2 hours and then at 180°C for 0.5 hours, and 105 parts by weight of ethylene carbonate was added with 0.45 parts by weight of NaOH. 364 parts by weight of low molecular weight alcoholizing fat were obtained. Then this low molecular weight alconylated resin 36
A resin having an acid value of 6.7 was obtained by esterifying 4 parts by weight and 29.6 parts by weight of phthalic anhydride at 180°C for 8 hours. 90 parts by weight of xylene, 30 parts by weight of ethylene glycol monoethyl ether acetate, and 30 parts by weight of butyl acetate were added to this resin to obtain a resin solution with a nonvolatile content of 70%.

To 100 parts by weight of this resin solution, 0.2 parts by weight of 12% cobalt octylate and 1 part by weight of 6% manganese O, naphthenate were added, and an appropriate amount of a leveling agent was added to obtain a clear face. Add 30 parts by weight of Takenate D-102 (trade name, manufactured by Narita Pharmaceutical Co., Ltd.) to 100 parts by weight of the obtained chestnut surface, adjust the paint, and apply it to a glass plate and a mild steel plate.
Dry at room temperature. The performance results are shown in Table 1.

Example 2 300 parts by weight of cashew nut shell liquid and 81 parts by weight of formalin
10 parts by weight in the presence of 0.45 parts by weight of NaOH catalyst.
After holding at 0°C for 3 hours and dehydrating under reduced pressure, it was heated at 130°C.
The reaction was continued for 1 hour and then at 180°C for 0.5 hour. 160 parts by weight of 105 parts by weight of ethylene carbonate was added to the obtained resin.
The reaction was carried out at 0.degree. C. to obtain 364 parts by weight of a low molecular weight alcoholized resin. The obtained low molecular weight alcoholized resin was reacted in the same manner as in Example 1, and the same treatment was performed to obtain a clear face. This clear face was applied to a glass plate and a mild steel plate, and its performance was investigated. The results are shown in Table 1.

Example 3 14 parts by weight of tolylene diisocyanate was added dropwise to a mixture of 60 parts by weight of the low-molecular alcoholized resin obtained in Examples 1 and 2 and 40 parts by weight of xylene, and the mixture was heated at 80°C for 1 hour and then at 100°C for 1 hour. The reaction was carried out to obtain a resin solution with a non-volatile content of 60%.

This resin solution was mixed with the same metal dryer and leveling agent as in Example 1, and then applied to a glass plate and a mild steel plate to examine its performance. The results are shown in Table 1.

Comparative Example 1000 parts by weight of cashew naphth shell liquid and 55 parts by weight of hexamethylenetetramine were reacted at 130°C for 2 hours and then at 180°C for 0.5 hour.

To this, 100 parts by weight of Kijirole, 10 parts by weight of ethyl cellosolve
0 parts by weight, add 100 parts by weight of Tsurupetz 6100,
A resin solution with a non-volatile content of 76% is obtained.

8% cobalt naphthenate 1 to 100 parts by weight of this resin solution
．． A clear varnish was obtained by adding 0.2 parts by weight of 6% manganese naphthenate and 0.5 parts by weight of an anti-skinning agent.

This clear varnish was applied to a glass plate and a mild steel plate, and the performance results are shown in Table 1.

Table 1 (Note) The drying conditions were as follows: The test was conducted after drying at 20° C. for 7 days. The test method in Table 1 is as follows.

(1) Drying time: The applied coating film was examined by touching it with a finger.

(2) Pencil hardness: A scratch test was conducted with a pencil.

(3) Gloss: 60 degree specular reflectance was examined.

(4) Odor: Judged by smelling the odor.

(5) Sumac fascination: There is no difference compared to Sumac membrane.

(6) Thick coating property: No distortion should occur at a film thickness of 100 μm.

(Fulbelling property: No difference from naturally dried cashew resin No. 53 transparent.

(8) Water resistance: Immersed in water at 20°C for 7 days.

(9) 73*lJ resistance: immersed in 5% caustic soda solution for 3 days.

αl acid resistance: Immersed in 5% hydrochloric acid solution for 3 days.

αυ Alcohol resistance: Immersed in 60% methanol solution for 3 days.

As is clear from Table 1, the curable resin composition containing the curable resin of the present invention has fast curing properties, has little odor, and the resulting coating film has high hardness. It was confirmed that it was.

Claims (1)

[Claims] 1. The following formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 may be the same or different for each unit, -CH_2-CH_2-OH, ▲ Numerical formula, chemical formula, There are tables, etc. ▼, -CH_2-CH_2-O-CH_2-
CH_2-OH or ▲There are mathematical formulas, chemical formulas, tables, etc.▼
, R_2 represents a hydrogen atom or -OR_1, R_3 represents an unsaturated hydrocarbon group having 3 to 17 carbon atoms and having 1 to 3 double bonds, and n is 3
A curable resin having a repeating unit represented by (representing an integer of ~500).