JP2002348530A - Curing agent for thermosetting type coating material, and coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material-curing agent capable of giving a thermosetting type coating material excellent in adhesion, adhesive strength, neutral salt water-spraying resistance and moisture resistance. SOLUTION: This thermosetting type coating material-curing agent consists of a blocked isocyanate obtained by reacting an isocyanate compound having >=2 isocyanato groups in 1 molecule with a phenol compound, wherein, the phenol compound is expressed by formula (1) (wherein, R<1> , R<2> and R<3> are each H, a 1-6C alkyl, an alkenyl or a phenylethyl, and among R<1> , R<2> and R<3> , at least one is the phenylethyl group) and is suitable as the curing material for a polyol-based or polyamine-based coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting block isocyanate widely used for paints, adhesives, sealing agents, etc., and more particularly, to a resin for improving physical properties of a coating film and a cured product. The present invention relates to a curing agent and a coating composition containing the same.

[0002]

2. Description of the Related Art Conventionally, thermosetting block urethane-based paints have been used for anticorrosion coating of steel structures and steel pipes, conductive wires, insulation of electronic substrates, and the like. Among them, blocked isocyanates are widely used as base resins and function-imparting agents. At present, in these fields, the balance between performance and cost is excellent. Therefore, a blocked isocyanate in which a bifunctional or higher functional isocyanate compound or a polyisocyanate obtained by crosslinking a bifunctional or higher functional isocyanate compound with a polyhydroxy compound or the like is terminal-blocked with phenols. Is often used. Generally used block isocyanates include toluidine isocyanate (TDI), diphenylmethane diisocyanate (MD)
I), two or more isocyanate groups (NC) in one molecule such as polymeric diphenylmethane diisocyanate
A blocked isocyanate obtained by reacting a polyvalent isocyanate compound having O) with an alkylphenol,
Block-modified isocyanates obtained by reacting a modified isocyanate compound obtained by crosslinking and oligomerizing the above polyvalent isocyanate compound with a bifunctional or higher polyhydroxy compound represented by diethylene glycol or trimethylolated propane, and an alkylphenol are known. Have been.

[0003] Of these blocked isocyanates or block-modified isocyanates, it is known to use styrenated phenol as a blocking agent. In JP-A-2-6548, a styrenated phenol block of a diisocyanate polymer is disclosed in JP-A-6-2938.
No. 78 discloses a styrenated phenol block of a polyisocyanate. In these styrenated phenol blocks of isocyanates, attention is paid to the ease of dissociation of the blocking agent due to the need for curing the coating film at a low temperature, but there is no viewpoint of delaying the dissociation reactivity. In addition, when blended and used as one component of paint, from the viewpoint of workability to facilitate blending with other raw materials,
It is common to add and react phenols in excess during the blocking reaction, dilute with a liquid solvent or a hydrocarbon solvent, dilute with a similar diluent after preparing the resin composition, and use it. is there.

However, these excess phenols, solvents and diluents are removed together with the blocking agent released by the exchange reaction during baking hardening, but insufficient removal results in a significant decrease in strength. If the conditions for removal are increased, for example, by raising the processing temperature or the degree of vacuum, foaming or waking phenomenon may occur and the appearance may be significantly reduced. For this reason, there are attempts to increase the removal rate of desorbed blocking agents such as phenols and diluents by adding a high boiling solvent or liquid plasticizer as a third component, but the addition of the third component decreases the physical properties after curing. There is a problem such as inviting. In addition, the removed volatile components lower the yield of the composition, there is a concern about the effect on the environment, and there is a problem that the burning cost increases the processing cost.
Furthermore, there is no viewpoint that the dissociated blocking agent is applied as a coating film modifier without removing the blocking agent. Furthermore, in recent years,
In addition to the sophistication of required performance, the demand for energy saving and low environmental load is also increasing. Coatings in the field,
There are demands for lowering the baking temperature, lowering the VOC, etc., as well as improving the strength, adhesion and durability of the cured product.

[0005]

An object of the present invention is to provide a coating film curing agent comprising an isocyanate compound blocked with a phenol compound, and a coating composition containing the same. In particular, by using a phenolic compound having a specific structure, the release reactivity is controlled, and a coating film curing agent capable of suppressing curing shrinkage or a coating film curing agent in which a release blocking agent has a coating film modifying effect. The present invention also provides a high-performance thermosetting coating composition which can be used for anticorrosion coating of steel structures and steel pipes, insulation of conductive wires and electronic substrates, and the like.

[0006]

According to the present invention, two molecules are contained in one molecule.
A paint curing agent comprising a blocked isocyanate obtained by reacting an isocyanate compound having at least two isocyanate groups with a phenol compound, wherein the phenol compound has the following formula (1)

Embedded image (Wherein R ¹ , R ² and R ³ are hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group or a phenylethyl group;
Wherein at least one of ¹ , R ² and R ³ is a phenylethyl group). In the general formula (1), it is preferable that R ¹ and R ² are 1-phenylethyl groups, or that R ¹ and R ² are hydrogen and R ³ is 1-phenylethyl group. One. Further, the present invention is the curing agent for a thermosetting paint, which generates a phenol compound represented by the general formula (1) in the paint composition, and the phenol compound has a coating film modifying ability. Furthermore, the present invention is a thermosetting coating composition comprising (A) a polyol or a polyamine, and (B) the curing agent for a thermosetting coating composition as an essential component.

The isocyanate compound used as a raw material for producing the blocked isocyanate used in the present invention is a general-purpose type or a non-yellowing type (discoloration under exposure to ultraviolet rays) as long as it has two or more isocyanate groups in one molecule. , Non-yellowing type (discoloration under ultraviolet exposure), etc. First, as a general-purpose type, tolylene diisocyanate (TD
I), isocyanurate, a trimer of TDI,
4'-diphenyldiphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate (polymeric MDI) and the like. Also,
Xylylene diisocyanate (XD
I) and the like. Further, non-yellowing types include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), hydrogenated XDI and hydrogenated MDI.
TDI, MDI, and polymeric MDI are preferred from the viewpoint of industrial availability and economical efficiency.

As a blocking agent, a phenol compound represented by the general formula (1) is used. R ¹ , R ² and R
Reference numeral ³ represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group, or a phenylethyl group, at least one of which is a phenylethyl group. As the alkyl group, a methyl group is preferably exemplified, and as the phenylethyl group, 1-
A phenylethyl group is preferably mentioned.

It is preferable that R ¹ and R ² of the phenol compound are 1-phenylethyl groups from the viewpoint of suppressing the elimination reaction from the blocked isocyanate. Since both ortho positions of the phenolic hydroxyl group are substituted with a phenylethyl group which is a bulky substituent, the elimination reaction of a phenol compound which is a blocking agent for an isocyanate group can be suppressed. Therefore, the curing shrinkage of the coating film progresses slowly, so that the curing shrinkage can be reduced or the stress generation inside the coating film can be suppressed, and as a result,
There is an advantage that coating durability is improved. In addition, the blocked isocyanate itself acts as a modifier, and has advantages such as prevention of foaming, improvement in adhesion, and improvement in durability.

Specific examples of such a phenol compound include 2,6-bis (1-phenylethyl) phenol, 2,6-bis (1-phenylethyl) -4-methylphenol, and 2,6-bis ( 1-phenylethyl) -4
-Ethylphenol, 2,4,6-tris (1-phenylethyl) phenol, and preferably 2,6-
Bis (1-phenylethyl) phenol, 2,4,6-
Tris (1-phenylethyl) phenol. Such a phenol compound can be produced by a known method. For example, there is a method in which styrene and phenol are reacted in the presence of a Lewis acid catalyst, and then the above compound is separated by distillation.

On the other hand, R ¹ and R ² are hydrogen, and R ³ is 1
-Phenylethyl group is preferable from the viewpoint that the elimination reaction is easy. In this case, it is necessary that hydrogen is bonded to the ortho position which is an obstacle to the elimination reaction. From the viewpoint of promoting the elimination reaction, the 1-phenylethyl group needs to be substituted at the para position. There are advantages such as easy desorption at low temperature and good workability, and no need for a desorption reaction catalyst, which is advantageous in terms of cost. Furthermore, not only the isocyanate compound after desorption acts as a coating film curing agent,
The released phenol compound also has a function as a coating film modifier, and is effective for preventing foaming, improving adhesion, improving durability, and the like. As a result, there is an advantage that the load for removing the phenol compound is reduced. Such a phenol compound is 4- (1-phenylethyl) phenol. Such a phenol compound can be produced by a known method. For example, there is a method in which styrene and phenol are reacted in the presence of a Lewis acid catalyst, and then the above compound is separated by distillation.

The production of the blocked isocyanate used as the curing agent for paints of the present invention can be obtained by reacting the above isocyanate compound with a phenol compound by a known method. For example, a method of heating and mixing may be used.
The thus obtained blocked isocyanate is preferably light-colored and soluble in a solvent such as toluene or xylene in order to exhibit desired properties. A blocked isocyanate obtained from a phenol compound in which R ¹ and R ² are 1-phenylethyl; and a phenol compound in which R ¹ and R ² are hydrogen and R ³ is 1-phenylethyl. If the blocked isocyanate obtained from the above is used in combination, both properties can be obtained or both properties can be averaged, and the properties can be changed so as to be suitable for use. The curing agent of the present invention can be used for applications other than coatings, and can be used as an additive for improving the strength of a thermoplastic resin composition, in addition to a film or a molding material.

The thermosetting coating composition of the present invention comprises (A) a polyol or a polyamine and (B) the curing agent for thermosetting coating (also referred to as the coating curing agent of the present invention) as essential components.

Here, the polyol is a compound containing two or more hydroxyl groups in one molecule, reacting with an isocyanate curing agent,
A hydroxyl equivalent of 100 to 2 capable of forming a crosslinked coating film
Of about 000, which can be used irrespective of liquid or solid. For example, a polyether polyol obtained by polymerizing an alkylene oxide, an epoxy-modified polyol having a bisphenol A-type epoxy resin skeleton, a polyester polyol, a polyether polyol, an acrylic polyol, a chelate-modified polyol, a castor oil-modified polyol, and the like can be used. One kind or two or more kinds may be used in combination. Further, in order to adjust the viscosity of the coating composition and the physical properties of the cured coating film, monofunctional alcohols may be used as a diluent.

Particularly, polyether polyols are preferred from the viewpoints of versatility, coating film performance, economy, and workability. More preferably, it is a polypropylene glycol-based polyether polyol having a molecular weight of 400 to 3000.

Here, polyamine refers to an amino group equivalent having an amino group equivalent of 10 or more which contains two or more amino groups in one molecule and is capable of reacting with an isocyanate curing agent to form a crosslinked coating film.
It is about 0 to 2000, which can be used regardless of liquid or solid. For example, linear aliphatic polyamines, cyclic aliphatic polyamines, aromatic polyamines, their adducts, modified polyamine compounds by cross-linking, and the like can be used, and one or two or more selected from these can be mixed. May be used. In particular, from the viewpoint of physical properties of the coated film after curing, a modified aromatic polyamine is preferred.

As the curing agent which is another essential component, the above-mentioned blocked isocyanate which is the coating material curing agent of the present invention is used. Further, in addition to the paint curing agent of the present invention, an isocyanate-based curing agent may be further added. As the isocyanate curing agent, any compound having two or more isocyanate groups in one molecule may be used. General-purpose type, non-yellowing type (discoloration under UV exposure), non-yellowing type (discoloration under UV exposure) ) Etc. can be used widely. As a general-purpose type, TD
I, isocyanurate, a trimer of TDI, MD
I, polymeric MDI and the like. In addition, examples of the non-yellowing type include XDI. Further, non-yellowing types include HDI, IPDI, hydrogenated XDI and hydrogenated MDI.
And adducts obtained by modifying the above isocyanates with polyhydric alcohols such as trimethylolpropane (TMP) and polyhydric phenols. In particular,
From the viewpoint of a balance between cost and performance, a TMP adduct of TDI and a polymeric MDI are preferred.

However, the amount of the blocked isocyanate used as the coating curing agent of the present invention is 5% of the total cyanate groups.
The amount occupies 0 mol% or more, preferably 70 mol% or more. The content of the paint curing agent of the present invention in all curing agents is 50% by weight or more, preferably 70% by weight or more,
It is more preferably at least 90% by weight. If the content of the present curing agent is less than this range, the effect of the present curing agent cannot be sufficiently obtained, which is not preferable.

The amount of the blocked isocyanate of the present invention or the amount of the blocked isocyanate of the present invention and another isocyanate curing agent used is based on the isocyanate group (NCO group).
The molar ratio of the hydroxyl group (OH group) / polyol resin is preferably in the range of 0.3 to 1.5, and more preferably in the range of 0.5 to 1.0 from the viewpoint of coating film performance.

The amount of the curing agent added is based on the number of moles of the hydroxyl group (OH) of the polyol resin or the active hydrogen (N—H) of the polyamine, and isocyanate group (NCO) in the isocyanate-based curing agent and blocking in the curing agent. The ratio of the total number of moles to the isocyanate group (—NHCOO—) is 0.3 to
It is blended to be 1.5. The amount of all curing agents used is 0.
If it is less than 3 (molar ratio), a satisfactory cured coating film cannot be obtained due to insufficient curing agent. 1.5 (molar ratio)
If the amount exceeds the range, foaming may occur or the physical properties may decrease.

The above-mentioned coating composition is generally used as a one-pack type coating composition mixed in advance, but can also be used as a two-pack type coating composition. In the case of using a two-pack type, the paint base agent and the curing agent are each in a liquid state, which is stored in a two-package form and mixed before use. The coating composition of the present invention includes both a two-part coating composition and a mixed coating composition.

In the coating composition of the present invention, commonly used coloring pigments, extenders, rust preventive pigments, various additives, solvents and the like can be blended in addition to the above essential components. Examples of the coloring pigment include inorganic coloring pigments such as titanium oxide, carbon black, and red iron oxide, and organic coloring pigments such as azo, cyanine, and quinacridone.
Examples of the extender include talc, calcium carbonate, barium sulfate, clay, silica, mica and the like.
As the rust-preventive pigment, for example, zinc oxide, which is an oxidative rust-preventive pigment, such as an alkaline pigment, such as lead oxide and lead red,
Zinc phosphate, zinc phosphomolybdate, which forms a rust preventive coating layer with a stable compound such as strontium chromate,
Aluminum phosphate and the like can be mentioned. There are no particular restrictions on the type, combination and blending ratio of the pigments to be used.
The amount is preferably in the range of 100 to 600 parts by weight with respect to 00 parts by weight. This is because the water vapor transmission rate of the coating film, which is a measure of the anticorrosion property, is minimized within the range of the blending ratio of the extender. On the other hand, in the case of a coloring pigment, it can be blended in an appropriate ratio according to a desired degree of coloring.
The content is preferably in the range of 00 parts by weight.

[0023] The coating composition of the present invention may further contain various conventional additives. For example, additives such as a pigment dispersant, an antifoaming agent, a leveling agent, and an anti-sagging agent can be used. As the solvent, an aromatic solvent such as toluene, xylene, a ketone solvent such as methyl ethyl ketone, methyl isobutyl ketone, an aliphatic ester solvent such as ethyl acetate, butyl acetate, or a mixed solvent thereof can be appropriately used. The thixotropic agent is added for the purpose of increasing the film thickness per coating, reducing the sagging of the coating film, further reducing the viscosity during coating and improving workability. Polyethylene oxide, fatty acid amide wax, organic bentonite and the like are used. The solvent may be added in a proportion of about 1 to 500 parts by weight based on 100 parts by weight of the main agent.

The coating composition of the present invention can be obtained by blending the above components in a cultivated area. For example, Disper,
The coating composition can be prepared by stirring and mixing with a ball mill or the like. An object to be coated, for example, an appropriate dry film thickness, for example, is applied with a brush coat or the like so as to have a thickness of about 200 to 300 μm, and the coated film is cured to form a target coated film. be able to. In addition, a dehydrating agent such as anhydrous gypsum or zeolite may be blended in the paint base agent or the paint composition in an amount of 1 to 5% by weight based on the total amount of the paint composition.

[0025]

The present invention will be described below with reference to examples. Example 1 25 parts by weight of phenol and 75 parts of styrene were placed in a glass reactor.
Parts by weight and 50 parts by weight of toluene, 1 part by weight of boron trifluoride diethyl ether complex was further added as a reaction catalyst, and the mixture was reacted at 80 to 85 ° C. for about 2 hours. After completion of the reaction, 3 parts by weight of calcium hydroxide was added for neutralization. After the neutralization treatment, the precipitate was removed by filtration, and the solvent was distilled off under reduced pressure to obtain a phenol compound. The main component of the phenolic compound is
It was tris [2,4,6- (1-phenylethyl)]-phenol, and its content was 75% by weight. 98% yield, semi-solid,
The viscosity (50 ° C., 25 poise) had an average molecular weight of 450 and a hydroxyl equivalent of 350. 75 parts by weight of the phenol compound and 25 parts by weight of MDI were mixed and dissolved by heating at 100 ° C.
Further, 4 mg of dibutyltin dilaurate was added, and
For 1 hour to obtain blocked isocyanate A.
The NCO content was 8.4%.

Example 2 Amine-modified polyol resin (manufactured by Asahi Denka Kogyo KK, trade name, ADEKA POLYETHER EDP-300, OH equivalent 760)
13 parts by weight of KOH mg / g) and 87 parts by weight of the block isocyanate A prepared in Example 1 were mixed and dissolved in 50 parts by weight of methyl ethyl ketone to prepare a one-part curing type paint varnish.

This was treated with a blasted steel plate (JIS-
G3141, 150 × 70 × 3.2 mm), dried at 60 ° C. for 1 hour, cured at 120 ° C. and 180 ° C. for 1 hour, adjusted the test plate, adjusted the paint Was evaluated. The same applies to the following other examples and comparative examples (excluding comparative example 5). The evaluation items for paints were the paint general test methods JIS K5400 and JI
SK5600, varnish test method for electrical insulation JIS C2
103, set based on the test method for liquid waste resin for electrical insulation. a) Neutral salt spray resistance: In accordance with JIS K5600 7-1, evaluation was made based on the presence or absence of abnormal appearance such as blistering and peeling after a 2-week accelerated test and the cross-cut peeling resistance. (○: good, Δ: slightly poor, ×: poor) b) Moisture resistance: In accordance with JIS K5600 7-2, the presence or absence of appearance abnormalities such as blistering and peeling after a 2-week accelerated test, and the cross-cut peeling resistance evaluated. (○: good, Δ: slightly poor, ×: bad) c) Adhesion: According to JIS K5600 5-6 adhesion (cross-cut method), set the cutter guide clearance to 2
mm and the number of squares were set to 25, and evaluated by the grid tape method. (Indicated by the number of squares remaining without peeling / 25) d) Adhesion strength: JIS K5400 (8.7) and JIS
It was measured by a tensile test according to K5600 5-7 adhesion strength (pull-off method). e) Impact resistance: 5 according to JIS K5600 5-3
The evaluation was performed using a weight of 00 g and a drop height of 20 cm. (Cracks, peeling, ○: not recognized,
Δ: slightly recognized, ×: recognized)

Example 3 60 parts by weight of phenol and 40 parts of styrene were placed in a glass reactor.
Parts by weight and 50 parts by weight of toluene, 1 part by weight of boron trifluoride diethyl ether complex was further added as a reaction catalyst, and the mixture was reacted at 80 to 85 ° C. for about 2 hours. After completion of the reaction, 3 parts by weight of calcium hydroxide was added for neutralization. After the neutralization treatment, the precipitate was removed by filtration, and the solvent and unreacted components were distilled off under reduced pressure to obtain a phenol compound. The main component is 4- (1-phenylethyl) phenol, which contains 50% by weight. The yield was 65%, the viscosity (30 ° C., 8 poise) average molecular weight was 280, and the hydroxyl equivalent was 230. 65 parts by weight of the phenol compound and 35 parts by weight of MDI were mixed and dissolved by heating at 100 ° C. Furthermore, dibutyltin dilaurate was added for 4m.
g was added and reacted at 120 ° C. for 1 hour to obtain blocked isocyanate B. The NCO content was 11.8%.

Example 4 Amine-modified polyol resin (manufactured by Asahi Denka Kogyo KK, trade name, Adeka polyether EDP-300, OH equivalent 760)
17 parts by weight of (KOH mg / g) and 83 parts by weight of the block isocyanate B prepared in Example 3 were mixed and dissolved in 50 parts by weight of methyl ethyl ketone to prepare a one-part curing type paint varnish.

Example 5 72 parts by weight of the phenol compound synthesized in Example 1 and polymeric MDI (MR20 manufactured by Nippon Polyurethane KK)
0, NCO content 30.8%)
It melted by heating at ° C. Furthermore, dibutyltin laurate 4
mg was added and reacted at 120 ° C. for 1 hour to obtain blocked isocyanate C. The NCO content was 8.6%.

Example 6 Polyether polyol resin (manufactured by Asahi Denka Kogyo KK, trade name, Adeka polyether P-400, OH equivalent: 268 KO)
Hmg / g) 30 parts by weight and 70 parts by weight of the block isocyanate C prepared in Example 5 were mixed, and methyl ethyl ketone 5
The solution was dissolved in 0 parts by weight to prepare a one-part curing type paint varnish.

Example 7 63 parts by weight of the phenol compound synthesized in Example 3 and 37 parts by weight of the above-mentioned polymeric MDI were mixed and dissolved by heating at 100 ° C. Furthermore, 4 mg of dibutyltin laurate was added and reacted at 120 ° C. for 1 hour to obtain blocked isocyanate D. The NCO content was 11.5%.

Example 8 36 parts by weight of the polyether polyol resin and Example 7
Was mixed with 64 parts by weight of the block isocyanate D prepared in the above, and dissolved in 50 parts by weight of methyl ethyl ketone to prepare a one-part curable coating varnish.

Comparative Example 1 In a glass reactor, 43 parts by weight of phenol, 57 parts by weight of MDI, and 50 parts by weight of xylene were mixed and heated and dissolved at 100 ° C. Furthermore, after adding 4 mg of dibutyltin dilaurate and reacting at 120 ° C. for 1 hour, xylene was distilled off to obtain blocked isocyanate E. NCO content 19.1%
Met.

Comparative Example 2 25 parts by weight of the amine-modified polyol resin and 75 parts by weight of the block isocyanate E prepared in Comparative Example 1 were mixed and dissolved in 50 parts by weight of methyl ethyl ketone to prepare a one-part curing type paint varnish. did.

Comparative Example 3 In a glass reactor, 41 parts by weight of phenol and 59 parts by weight of the above-mentioned polymeric MDI were mixed with 50 parts by weight of xylene and dissolved by heating at 100 ° C. Furthermore, after adding 4 mg of dibutyltin dilaurate and reacting at 120 ° C. for 1 hour, xylene was distilled off to obtain blocked isocyanate F. NC
The O content was 18.3%.

Comparative Example 4 48 parts by weight of the polyether polyol resin and Comparative Example 3
Was mixed with 50 parts by weight of methyl ethyl ketone to prepare a one-part curable coating varnish.

Comparative Example 5 57 parts by weight of MDI were dissolved in 50 parts by weight of methyl ethyl ketone, and 43 parts by weight of the amine-modified polyol resin were mixed and stirred immediately before coating on a test plate to prepare a one-part curing type coating varnish. This was applied to the blasted steel sheet so as to have a dry film thickness of 100 μm, dried at 60 ° C. for 1 hour, and then cured at 120 ° C. for 1 hour to prepare a test plate. Table 1 summarizes the evaluation results.

[0039]

[Table 1]

[0040]

The paint curing agent of the present invention can provide a thermosetting paint excellent in adhesion, adhesion strength, neutral salt spray resistance and moisture resistance. It is also useful as a molding material, a resin modifier and the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshihiro Yamamoto 46 at 46, Hamahara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka F-term in Nippon Steel Chemical Research Laboratory 4J034 CA14 DA01 DF01 DG02 DG14 DP18 EA12 HA07 HB07 HC03 HC12 HC17 HC22 HC35 HC46 HC64 HC67 HC71 HC73 HD03 RA07 4J038 DG051 DG061 DG111 DG131 DG161 DG271 DG281 DG291 DG301 NA11 NA12 NA27 PB05 PB09 PC02

Claims (5)

[Claims] 1. A paint curing agent comprising a blocked isocyanate obtained by reacting an isocyanate compound having two or more isocyanate groups in one molecule with a phenol compound, wherein the phenol compound has the following formula (1) 1) (Wherein R ¹ , R ² and R ³ are hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group or a phenylethyl group;
Wherein at least one of ¹ , R ² and R ³ is a phenylethyl group). 2. In the general formula (1), R ¹ and R ² are 1
The curing agent for a thermosetting paint according to claim 1, which is a phenol compound that is a phenylethyl group. 3. The curing agent for a thermosetting paint according to claim 1, wherein in formula (1), R ¹ and R ² are hydrogen and R ³ is a phenol compound having a 1-phenylethyl group. 4. The curing agent according to claim 3, wherein a phenol compound represented by the general formula (1) is generated in the coating composition, and the phenol compound has a coating film modifying ability. 5. (A) a polyol or polyamine,
(B) A thermosetting paint composition comprising the curing agent for thermosetting paint according to any one of claims 1 to 4 as an essential component.