JP3148408B2 - High solid content resin composition, high solid content type paint using the same, and coating and baking method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel and useful high solid content resin composition, a high solid content type paint using the same, a coating method and a baking method. More specifically, the present invention provides, in part, a method comprising a specific acrylic oligomer having blocked hydroxyl groups, a specific polyester oligomer, a hydroxyl reactive curing agent, and a dissociation or curing catalyst. A solid-state resin composition and a high-solids-type paint; two high-resin compositions mainly comprising a low-viscosity acrylic oligomer obtained by blocking a hydroxyl group with a specific compound thus obtained. In addition, when coating and baking a high solid content type paint, one coat and one bake (hereinafter, abbreviated as "1C-1B") is provided in which the object to be coated is rotated about a substantially horizontal axis so as not to cause sagging. ), 2 coats 1 bake (hereinafter “2C-1
B ". ), 2 coats, 2 bake (hereinafter, “2C
-2B ". ) 3 coats 2 bake (hereinafter,
Abbreviated as "3C-2B". ) And a method for applying and baking a resin composition and a paint in an overcoat system.

[0002]

2. Description of the Related Art In recent years, in automotive exterior panel coating, a 2C-1B finish line coating is performed in the form of a combination of an acrylic polyol and a melamine resin. A large amount of solvent is released into the atmosphere from this painting line,
Moreover, by burning this discharged solvent,
There was a problem that the global warming phenomenon caused by the generation of a large amount of carbon dioxide would be accelerated. Investigations on water-based treatment have been widely conducted mainly on base coats. The clear coat is required to have a high appearance and various coating properties such as durability. Water-based paint, powder paint,
Although UV-curable paints and the like are also being widely studied, reducing the solvent used in conventional resins is the shortest route.

However, when the molecular weight of the conventional acrylic polyol-melamine resin combination is reduced to achieve high solid differentiation, the content of hydroxyl groups must be increased in order to compensate for insufficient curing. By this means, it is not always possible to achieve a low viscosity, and, furthermore, a coating film obtained by curing a resin having a high hydroxyl value with a melamine resin has an extremely low acid resistance. Invite you. In addition, at the time of coating, there is an inconvenience that dripping of the vertical surface due to the reduction in viscosity is remarkable.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned various problems in the prior art, to realize a reduction in viscosity, an improvement in acid resistance, and an improvement in scratch resistance, and to provide an armpit or a brush. It is an object of the present invention to provide a resin composition that does not cause sagging, and to provide a very useful coating method and baking method with improved various properties.

[0005]

The inventors of the present invention have conducted intensive studies in accordance with the objects of the present invention as described above. It has been found that it is performed by a method such as lowering the transition temperature.

That is, in order to reduce the polarity of a low-molecular-weight acrylic resin, the present inventors have proposed a method in which a hydroxyl group is blocked with a specific blocking agent and has a molecular weight of 1,500 or less and a hydroxyl group after dissociation. The concentration is 2.2 mol / 100
Acrylic oligomer (a) having a molecular weight of 1,500 or less and 2.0 mol / 1,000
A specific high solids resin composition comprising a polyester oligomer (b) having a hydroxyl group concentration of 0 g or more, a curing agent (c) reactive with hydroxyl groups, and a dissociation or curing catalyst (d); It has been found that by using a high solid content type paint, it is possible to finish a coating film having a low viscosity and free from cracks and sagging, and completed the present invention.

That is, the present invention relates to an acrylic oligomer (a) having a blocked hydroxyl group, a number average molecular weight of 1,500 or less, and a hydroxyl group concentration after dissociation of 2.2 mol / 1,000 g or more. ) And a number average molecular weight of 1,50
0 or less, and the hydroxyl group concentration is 2.0 mol / 1,000
g, a high solid content resin comprising a polyester oligomer (b) having a molecular weight of at least g, a curing agent (c) reactive with a hydroxyl group, and a dissociation catalyst or a curing catalyst (d) as essential film-forming components. It provides a composition. The present invention
In the high solid content resin composition, the acrylic oligomer
-(A), the polyester oligomer (b), and
The curing agent (c) and the dissociation catalyst or curing catalyst (d)
Is preferably an acrylic oligomer (a)
100, polyester oligomer (b) is 11
-100, 0.001 of dissociation catalyst or curing catalyst (d)
And acrylic ester (a) and polyester
Curing agent for a total amount of 100 with the oligomer (b)
(C) is set within the range of 52 to 192.

[0008] The present invention also provides a high solid content resin composition of the present invention.
It is intended to provide a high solid content type coating material using a product as a binder .

Further, the present invention provides 1C-1B, 2C-1B,
2C-2B, 3C-2B and a method of applying a paint in an overcoat system, wherein the high solid content resin composition of the present invention or the high solid content type paint of the present invention is applied to an object to be coated. On the vertical surface of the object, before the sagging of the paint starts to occur, and until the paint no longer sags, by rotating the object about a substantially horizontal axis, substantially The present invention provides a coating method for performing coating without sagging.

The present invention also relates to 1C-1B, 2C-1B,
A method for baking a paint in 2C-2B, 3C-2B and an overcoat system, comprising applying a high solid content resin composition of the present invention or a high solid content type paint of the present invention to an object to be coated. When baking, on the vertical surface of the object to be coated, before sagging of the paint begins to occur, and
Until the paint does not cause sagging, the coating object is rotated about a substantially horizontal axis to perform substantially sagging coating, and then baking, which provides a paint baking method. is there.

In the present invention, the blocked hydroxyl group refers to a group having a structure represented by the following general formulas (I), (II) and (III).

[0012]

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(R ₁ and R ₂ in the formula each represent an alkyl group having 1 to 18 carbon atoms, a phenyl group or an aryl group, or a hydrogen atom, a chlorine atom or a fluorine atom. And R ₃ represents an alkyl group having 1 to 18 carbon atoms, a phenyl group or an aryl group.)

[0014]

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(R ₄ in the formula is a hydrogen atom or a group having 1 carbon atom.
Represents an alkyl group of 10 to 10, and R ₅ is at least selected from the group consisting of a cycloalkyl group, an aralkyl group, an aryl group, an alkoxyl group, an alkanoyloxy group, an alkyl group having 1 to 18 carbon atoms and a halogen atom. 1 to 22 carbon atoms substituted by one kind of atomic group
Represents an alkyl group. )

[0016]

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(Wherein X is at least one atom selected from the group consisting of an alkoxyl group, an aralkyl group, an aryl group, an aryloxy group, an alkanoyloxy group, an alkyl group having 1 to 10 carbon atoms and a halogen atom) Represents an alkyl group having 1 to 18 carbon atoms which may or may not be substituted with a group.)

Further, in the present invention, the expression that the hydroxyl group concentration after dissociation is 2.2 mol / 1,000 g or more means that
It defines the number of moles of hydroxyl groups present in 0 g of acrylic oligomer, and indicates that the oligomer has an abundance of 2.2 mol or more, that is, an existing concentration in a unit of 1,000 g of the oligomer. It is.

Examples of the above-mentioned monomers having the structure represented by the general formula (I) include trimethylsiloxyethyl (meth) acrylate and trimethylsiloxyethyl (meth) acrylate.
Including trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, triethylsiloxyethyl (meth) acrylate or tributylsiloxypropyl (meth) acrylate, triphenylsiloxyalkyl (meth) acrylates or dimethyl-tert-butyl And siloxyalkyl (meth) acrylates.

That is, it is a form in which a hydrogen atom of a hydroxyl group in a hydroxyl group-containing polymerizable unsaturated monomer is blocked with a so-called silylating agent, but only in the above-mentioned monomers. It is not limited. That is, N-methylolated (meth) acrylamide or β-hydroxyethyl (meth) acrylate is reacted with ε-caprolactone, or various (meth) acrylates of polyoxyalkylene glycols are silylated. Strained ones can also be used.

As typical examples of the monomers having the structure represented by the general formula (II), 1-methoxy-ethoxyethyl (meth) acrylate, 1-ethoxy-ethoxyethyl ( (Meth) acrylate, 1-butoxyethoxyethyl (meth) acrylate, 1- (2-ethylhexanoxy) -ethoxyethyl (meth) acrylate, 1-isobutoxy-ethoxyethyl (meth) acrylate, 1-cyclohexyloxy-ethoxy Various 1-alkoxy-ethoxyethyl (meth) acrylates, such as ethyl (meth) acrylate.

That is, it is a form in which an alkyl vinyl ether is added to a hydrogen atom of a hydroxyl group in a hydroxyl group-containing polymerizable unsaturated monomer by addition reaction, but is limited to only the above-mentioned monomers. Not something. That is, N-methylolated (meth) acrylamide and β-hydroxyethyl (meth) acrylate are reacted with ε-caprolactone, or polyoxyalkylene glycols (meth) acrylates. Can also be used in the form of an addition reaction of the above vinyl ethers.

Examples of the monomers having the structure represented by the above-mentioned general formula (III), which are particularly typical, include those represented by the following chemical formula.

[0024]

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[0025]

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[0026]

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[0027]

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The number of carbon atoms of X in the general formula (III) is usually in the range of 1 to 18, preferably 2 to 6.

The amount of these various hydroxyl-blocked monomers is suitably in the range of 0.5 mol / 1,000 g to 4 mol / 1,000 g. When the amount is less than 0.5 mol / 1,000 g, the effect on lowering the viscosity is small. On the other hand, when the amount exceeds 4 mol / 1,000 g, the effect of the volatilization by the blocking agent is smaller than the effect of decreasing the viscosity. In any case, it is not preferable because it increases the number of minutes.

Further, polymerizable monomers having unblocked hydroxyl groups themselves can also be used. In particular, the use of monomers having good solubility is preferred. Illustrative examples of only such typical monomers include β-
A compound obtained by adding 1 to 6 mol of ε-caprolactone to hydroxyethyl (meth) acrylate, or (meth) acrylates of polyoxyalkylene glycol; hydroxyethyl acrylate, 3-hydroxypropyl (meth) acrylate; Various (meth) acrylates such as 4-hydroxybutyl (meth) acrylate and 2,3-dihydroxypropyl (meth) acrylate; various vinyl ethers such as hydroxyethyl vinyl ether and hydroxybutyl vinyl ether; allyl ether, hydroxyethyl Various allyl compounds such as aryl ethers; or monomers obtained by reacting glycidyl (meth) acrylate with oxycarboxylic acids; (meth) acrylic acid;
Monomers obtained by reacting a compound having one epoxy group; oligomers obtained by reacting fatty acids and hydroxy acids with epoxy group-containing oligomers; or oligomers containing carboxylic acid-containing oligomers Monomers obtained by reacting a compound having two epoxy groups.

The total amount of the monomers in which the hydroxyl groups are blocked and the hydroxyl group-containing monomers described above is 2.2 mol / mol in terms of the concentration of the hydroxyl groups after dissociation.
1,000 g or more, preferably 2.8 mol / 1,000
0 g or more is appropriate. If the amount is less than 2.2 mol / 1,000 g, a coating film having a sufficient cross-linking density cannot be obtained.

As other monomers which can be copolymerized with the above-mentioned monomers, particularly typical ones are listed below. Monohydric alcohols having 1 to 22 carbon atoms and (meth) acrylic Various alkyl (meth) acrylates, which are esterified with acid, styrene, vinyltoluene, t
various alkyl esters such as tert-butylstyrene, glycidyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth) acrylonitrile, cyclohexyl (meth) acrylate; (meth) acrylic acid or crotonic acid or Maleic acid,
Various unsaturated carboxylic acids such as fumaric acid or itaconic acid; maleic acid or fumaric acid and one carbon atom
Mono- or diesters with monohydric alcohols represented by the following formulas: (meth) acrylamide, (meth) dimethylacrylamide, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate; -Dialkylaminoalkyl (meth) acrylates; various phosphoric acid group-containing (meth) acrylates such as phosphonooxyethyl (meth) acrylate; α-olefins such as vinyl acetate, hexafluoropropylene and tetrafluoroethylene;
Or perfluoroalkyl / perfluorovinyl ethers such as trifluoromethyl trifluorovinyl ether and pentafluoroethyl trifluorovinyl ether; (per) fluorovinyl ethers; and perfluoroalkyl vinyl ethers (provided that the alkyl group has 1 to 18 carbon atoms). ). Of course, these vinyl monomers may be used alone or in combination of two or more depending on the desired coating film performance.

The acrylic oligomer obtained by copolymerizing the above-mentioned components has a number average molecular weight of 1,500.
The following is preferably in the range of 700 to 1,200. If it exceeds 1,500, the viscosity in a soluble or non-solvent state is extremely increased, and the amount of the diluting solvent is extremely increased, which is not preferable.

The polymerization of these monomers can be carried out by a known and commonly used method. Preferably, it can be easily carried out by a radical solution polymerization method. Methods for obtaining a low molecular weight polymer include a method using various chain transfer agents, including mercaptan compounds such as mercaptoethanol, thioglycerol, and lauryl mercaptan, and a method using a high temperature (usually within a range of 140 to 180 ° C). Alternatively, the desired acrylic oligomer having a blocked hydroxyl group can be easily obtained by a method of performing the reaction at a low monomer concentration.

Here, when only typical solvents are exemplified, typical solvents such as xylene, “Solvesso” (manufactured by Exxon), butyl acetate, methyl ethyl ketone, methyl amyl ketone, butyl acetate, ethyl acetate, etc. Any solvent used in the production of the acrylic polymer can be used. When a melamine resin is used as one kind of the hydroxyl-reactive curing agent (c), an alcohol-based solvent such as n-butanol, isobutanol, and butyl cellosolve can also be used.

The radical polymerization initiator can also be used if it is usually used. Among them, particularly typical ones are exemplified as benzoyl peroxide, lauroyl peroxide, tert-butyl hydroperoxide, tert-butylperoxy-2-ethylhexanoate, tert-amylperoxy-2-. Various peroxides such as ethylhexanoate and tert-amylperoxybenzoate; or various azo compounds such as azobisisobutyronitrile and azobis (2-methylpropionitrile). Also, such as anionic polymerization and cationic polymerization,
The so-called ionic polymerization method can be particularly advantageously used for copolymerization of monomers having a blocked hydroxyl group. Moreover, the thus obtained acrylic oligomer having a blocked hydroxyl group can be used as a component of the high solid content resin composition of the present invention or the high solid fractionating paint of the present invention, respectively, without regenerating the hydroxyl group. Can be used as is.

The polyester oligomer (b), which is also referred to as the second component in the present invention, will be described. The polyester oligomer (b) can significantly improve the abrasion resistance required for a coating film for automobiles, etc., by being used in combination with the acrylic oligomer (a) having a blocked hydroxyl group as the first component. It is.

Such a polyester oligomer (b)
Examples thereof include phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, and tetrahydrohydric acid. Various polycarboxylic acids represented by phthalic anhydride, ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, cyclohexanedimethanol, neopentyl glycol, hydrogenated Bisphenol A, 1,6-hexanediol, glycerin, trimethylolethane, trimethylolpropane, various polyhydric alcohols represented by pentaerythritol, and further, various fatty acids as molecular weight regulators, benzoic acid, p -Tert Butyl benzoic acid, 1, such as rosin
Carboxylic acids or "Kajura E10"
(Trade name; monoepoxy compound, manufactured by Shell Co., The Netherlands) or the like, and the desired hydroxyl-containing polyester oligomer can be synthesized by these dehydration condensation reaction or addition reaction.

The molecular weight of the polyester oligomer (b) is suitably such that the number average molecular weight is 1,500 or less, preferably in the range of 400 to 1,000.
If it exceeds 1,500, the viscosity of the obtained resin composition and, consequently, the viscosity of the obtained paint will be extremely increased when used in combination with the first component.

As the curing agent (c) (hydroxyl-curable curing agent) having reactivity with a hydroxyl group used in the present invention, first, a polyisocyanate compound can be mentioned.
To illustrate only typical ones among them,
Xylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, tolylene diisocyanate or hexamethylene diisocyanate,
1,4-tetramethylene diisocyanate, 1,10-
Including various alkylene diisocyanate compounds such as decamethylene diisocyanate and 1,18-octadecamethylene diisocyanate, these various alkylene diisocyanate compounds, ethylene glycol,
Adducts with various polyhydric alcohols such as glycerin or trimethylolpropane; or reactive with so-called active hydrogen such as a reaction product of 1 mol of water with 3 mol of diisocyanates Having a free isocyanate group, and any known and commonly used compounds can be used. The most effective one as the polyisocyanate compound in the present invention is one having an isocyanurate ring, which is advantageous for hardness and low viscosity.

As the hydroxyl-reactive curing agent (c), 2
The second most important one is an alkylated melamine / formaldehyde resin, and those having a carbon number of 1 to 4 are usually used.

That is, so-called lower alcohols of C _{1 to} C ₄ , which are obtained partially or completely by etherification, specifically, methyletherified melamine, For example, n-butyl etherified melamine or iso-butyl etherified melamine. Among these, from the viewpoint of high solid differentiation,
The use of methyl etherified melamine is preferred.

As the blocked polyisocyanate, polyisocyanates obtained by blocking a so-called non-yellowing polyisocyanate with a known and commonly used blocking agent are used.
550 "(trade name; product of Dainippon Ink and Chemicals, Inc.)," Takenate B815-N "(trade name; product of Takeda Pharmaceutical Co., Ltd.) or" Azitol VKL-8 "
“0” (trade name; a product of Hoechst Gosei Co., Ltd.) is an example of a typical commercially available product.

Next, there can be mentioned an acid anhydride group-containing compound. As such a compound, an acid anhydride group-containing unsaturated monomer is copolymerized with a polymerizable monomer as described above. The resulting acid anhydride group-containing vinyl copolymers are particularly typical. Here, when only typical examples of the acid anhydride group-containing unsaturated monomers are given, examples thereof include those which are represented by itaconic anhydride, maleic anhydride and the like. In addition, when only typical examples of the acid anhydride group-containing low molecular weight compound are exemplified, trimellitic acid, tetrahydrophthalic anhydride, hetic anhydride, hymic anhydride, maleic anhydride, itaconic anhydride, pyromellitic anhydride Or glycerol tris (trimellitate).

The dissociation catalyst or curing catalyst (d), which is also referred to as the fourth component in the present invention, refers to a compound which is hydrolyzed by a reaction with moisture in the air to regenerate a hydroxyl group. . It goes without saying that in order to promote such hydrolysis, it is necessary to use a catalyst. However, when only typical catalysts are exemplified, phosphoric acids, phosphoric esters, phosphites, Various acidic catalysts such as phosphoric esters containing a saturated group, p-toluenesulfonic acid or an amine salt thereof; benzoic acid, trichloroacetic acid, naphthalene disulfonic acid or an amine salt thereof, and tetraethylammonium fluoride. And compounds that generate halide ions such as chloride are effective.
You.

The catalyst for accelerating the reaction between the generated hydroxyl group and the above-mentioned polyisocyanate compound as a curing agent is not particularly limited as long as it is one usually used as a urethanization catalyst. It can be used without. As particularly typical examples of such urethanization catalysts, metal salts of various carboxylic acids such as alkyl titanates, octylates, dibutyltin dilaurate, lead octylate; monobutyltin sulfide, dioctyltin mercaptite And various sulfide-type or mercaptide-type organotin compounds. The amount of these is preferably in the range of 0.001 to 5% based on the acrylic oligomer,
A range of 0.005 to 2% is appropriate.

In the high solid content resin composition of the present invention,
The acrylic oligomer (a) and the polyester
Sesame (b), the curing agent (c), and the dissociation catalyst.
Or the weight ratio with the curing catalyst (d) is
-(A) 100, polyester oligomer
(B) is 11 to 100, a dissociation catalyst or a curing catalyst (d)
Is 0.001 to 10, more preferably 0.005 to 6.
Acrylic oligomer (a) and polyester oligomer
Curing agent (c) is 52 with respect to a total amount of 100
It is preferable to set appropriately within the range of １９192. Furthermore, if necessary, the high solid content resin composition or the high solid content type paint of the present invention (hereinafter, both of these may be represented as a resin composition, or conversely, may be represented as a paint. ), Various resins and solvents, various colorants such as pigments and dyes, flow regulators, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, etc. It goes without saying that various known and commonly used additives can be added. In particular, as a solubilizer, the use of so-called dipolar aprotic solvents having high water absorption is effective.

Next, using the resin composition of the present invention, 1
A coating method and a baking method of a paint (including a resin composition in some cases) in the C-1B, 2C-1B, 2C-2B, 3C-2B and overcoat system will be described. The resin composition of the present invention is used at the time of coating, in a state diluted with a minimum amount of solvents or in a state without solvent. And, when coating in any state, at the time of coating, the blocking agent dissociates in an atomized state, and when applied to the object to be coated, already regenerates the hydroxyl group and sharply It is to thicken. Therefore, it is less likely to sag as compared with the conventional one in which the viscosity is reduced only with solvents.

That is, in the case of a paint containing a large amount of solvents as in the prior art, a so-called primary sagging in the coating process can be prevented by a sudden increase in viscosity due to the evaporation of the solvent. As in the present invention, in the case of a solvent-free or low solvent content, high solid content resin composition or high solid content type paint, immediately after coating,
There is always the danger that sagging will occur on the surface of the coating object that extends vertically, that is, on the vertical surface, which will eventually cause poor coating film appearance (poor appearance).

In this respect, in the coating method of the present invention, the coating is performed while continuously rotating the object to be coated about a substantially horizontal axis, and at least in the drying step, until the coating no longer sags. Since the rotation is maintained from start to finish, it is difficult for primary sagging to occur, and even if it occurs, such primary sagging can be smoothed.

Therefore, in order to prevent so-called secondary sagging in the baking process, in order to prevent this, the operation of rotating around a substantially horizontal axis, which is a feature of the coating method or the baking method of the present invention, is performed from the painting step. It is absolutely necessary to continuously maintain it throughout the baking process.

The coating or baking method used in the present invention for rotating an object to be coated about a substantially horizontal axis is disclosed in
Although it is disclosed in US Pat. No. 1,658,871, the effect can be further expected by using the resin composition or the paint of the present invention. The rotation speed of the object is
Before gravity causes the composition of the present invention to sag, the rotational speed is changed from a vertical state to at least a horizontal state, and the centrifugal force resulting from the rotation causes sagging of the paint. The rotation speed is set to a range smaller than the rotation speed.

The coating conditions are as follows. The resin composition or the paint is heated, and the acrylic oligomer (a), the polyester oligomer (b) and the hydroxyl-reactive curing agent (c) in the composition of the present invention are used. And a dissociation or curing catalyst (d)
These can be blended immediately before use, and can be applied by various methods such as air atomization coating and airless coating.

The high solid content resin composition or high solid content type paint of the present invention is applied to so-called metal materials or metal products, such as automobiles and building materials, by the coating method and the baking method of the present invention. Can be applied to

[0055]

EXAMPLES Next, the present invention will be described more specifically with reference examples, examples, application examples and comparative application examples. In the following, all parts and percentages are by weight unless otherwise specified. It is assumed that

Reference Example 1 (Preparation Example of Acrylic Oligomer Having Blocked Hydroxyl Group) 1,000 parts of xylene was placed in a four-necked flask equipped with a stirrer, an inert gas inlet, a thermometer, and a cooler. And heated to 140 ° C., and then 250 parts of trimethylsiloxyethyl methacrylate, 80 parts of styrene, “Placcel FM-1” (trade name; 2-hydroxylethyl methacrylate manufactured by Daicel Chemical Industries, Ltd.) a mixture of 120 parts of ε-caprolactone), 50 parts of n-butyl acrylate, 500 parts of xylene, 30 parts of azobisisobutyronitrile and tert-butyl peroxy- 50 parts of 2-ethylhexanoate were added dropwise over 6 hours.

Further, the reaction was carried out at the same temperature for 5 hours to obtain a resin solution having a nonvolatile content of 25%, and then xylene was distilled off under reduced pressure. 2 of the resin solution obtained here
The viscosity at 5 ° C. was 1,800 centipoise, and the molecular weight of the resin was 980. (Hereinafter OH
Abbreviated as B-1. )

Reference Example 2 (Preparation Example of Acrylic Oligomer Having Blocked Hydroxyl Group) After 1,000 parts of methyl amyl ketone was charged, 50 parts of styrene, 300 parts of trimethylsiloxybutyl acrylate, and “Placcel FM” A resin solution was obtained in the same manner as in Reference Example 1, except that a monomer mixture consisting of 100 parts of "-1" and 50 parts of n-butyl methacrylate was used.

The resin solution obtained here had a nonvolatile content of 2
7.8%, and the viscosity of the resin from which the solvent was distilled off was 1,90.
It was 0 centipoise and the molecular weight was 880. (Hereinafter abbreviated as OHB-2)

Reference Example 3 (Preparation Example of Acrylic Oligomer Having Blocked Hydroxyl Group) In the same apparatus as in Reference Example 1, dehydrated 1-methoxy-
A monomer mixture consisting of 350 parts of ethoxyethyl methacrylate, 100 parts of n-butyl methacrylate and 50 parts of 2-ethylhexyl methacrylate was charged, and a solution of sec-butyl-Li / benzene having a weight ratio of 20/80 was further added. Add 100 parts and add 2 at 25 ° C
After stirring for a time, add 20 parts of hydrochloric acid-methanol, remove the solvent, and filter, and then a resin having a molecular weight of 1,000 and a viscosity of 1,800 centipoise. A solution was obtained. (Hereafter, this is OH
Abbreviated as B-3. )

Reference Example 4 (Preparation Example of Acrylic Oligomer Having Blocked Hydroxyl Group) In the same apparatus as in Reference Example 3, 250 parts of trimethylsiloxyethyl methacrylate and 250 parts of n-butyl methacrylate were subjected to dehydration treatment. The monomer mixture was further charged with 200 parts of tetrahydrofuran which had been previously dehydrated, and naphthalene and sodium metal were reacted in tetrahydrofuran at a molar ratio of 1: 1. Green complex (Na-naphthalene)
Was added and stirred for 2 hours to give a molecular weight of 1,
After obtaining a polymer of 500, 20 parts of methanol was added and sufficiently stirred, and then the solvent was distilled off to obtain a solventless resin having a viscosity of 2,000 centipoise.
(Hereinafter, this is abbreviated as OHB-4.)

Reference Example 5 (Preparation Example of Acrylic Oligomer Having Blocked Hydroxyl Group) In a 3-liter autoclave, 1,000 xylene was added.
g, and set so as not to leak. After the temperature was raised to 160 ° C., 100 parts of styrene, 300 parts of n-butyl methacrylate, 600 parts of trimethylsiloxyethyl methacrylate, and di-tert-butyl peroxide were added. Of a mixture of 100 parts by weight over 5 hours, and after further reacting for 4 hours, xylene was distilled off to give a solvent having a viscosity of 2,200 centipoise and a molecular weight of 1,200. , 100 acrylic oligomers were obtained. (Hereinafter, this is abbreviated as OHB-5.)

Reference Example 6 (Preparation Example of Polyester Oligomer Having Hydroxyl Group) A four-necked flask equipped with a stirrer, an inert gas inlet and an air condenser was charged with 550 parts of trimethylolpropane and 1,4-cyclohexane. Dicarboxylic acid 4
After charging 25 parts and 550 parts of 1,6-hexanediol, the temperature was raised to 140 ° C, and then to 160 ° C.
Over 3 hours, the temperature is gradually increased to carry out a dehydration condensation reaction. Subsequently, the temperature is increased to 220 ° C. to obtain a number average molecular weight of 850, a hydroxyl value of 180, and an acid value of 2 Was obtained. (Hereinafter referred to as PE-1
Abbreviated. )

Reference Example 7 (Preparation Example of Polyester Oligomer Having Hydroxyl Group) Using the same apparatus as in Reference Example 7, 150 parts of melamine and 500 parts of butanol were charged, and the temperature was raised to 120 ° C. And then 1.0 part of triphenylphosphine,
After dripping 720 parts of "Kajura E10",
After reacting for 7 hours, the number average molecular weight is 1,180,
In addition, a triazine group-containing oligomer having a hydroxyl value of 200 was obtained. (Hereinafter, this is abbreviated as PE-2.)

Reference Example 8 (Preparation Example of Polyester Oligomer Having Hydroxyl Group) Using the same apparatus as in Reference Example 7, 250 parts of pentaerythritol, 550 parts of ε-caprolactone and 2 parts of a zinc salt of acetylacetone were used. Charge, 4 at 160 ° C
The reaction was performed for a time, and it was confirmed that the system became homogeneous. The oligomer thus obtained had a number average molecular weight of 720 and a hydroxyl value of 250. (Hereinafter referred to as PE-
Abbreviated as 3. )

Reference Example 9 (Preparation Example of Acrylic Oligomer Having Hydroxyl Group) 500 parts of xylene and 300 parts of n-butanol were charged, and 100 parts of styrene and 6 parts of butyl acrylate were added.
0 parts, 195 parts of β-hydroxyethyl methacrylate and 145 parts of “Placcel FM-1” and a mixture of 75 parts of tert-butylperoxy-2-ethylhexanoate, except that the mixture was changed to use. Was reacted in the same manner as in Reference Example 1 and then desolvated to give a viscosity of 40 poise and a number average molecular weight of 1,120. (Hereafter, this is OH
Abbreviated as -1. )

Reference Example 10 (Preparation Example of Acrylic Oligomer Having Hydroxyl Group) To the blocked hydroxyl group-containing acrylic resin obtained in Reference Example 4, a 10% aqueous solution of phosphoric acid was added, and the mixture was sufficiently stirred and dehydrated. As a result, a resin having a resin viscosity of 40 poise and a molecular weight of 1,200 was obtained. (Hereinafter, this is abbreviated as OH-2.)

[Examples 1 to 6] Using the resins obtained in Reference Examples 1 to 5 and Reference Examples 6 to 8 according to the composition ratios shown in Table 1 below, the resins of the present invention were used. A composition was prepared.

[Comparative Examples 1 and 2] Reference Examples 9 and 1
Using the respective resins obtained in Step No. 0, a resin composition for control was prepared in accordance with the compounding ratio shown in Table 1 below.

[Application Examples 1 to 6 and Comparative Application Example 1]
And 2] The resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were mixed with xylene / butyl acetate (weight ratio = 60 /
The viscosity was adjusted with the mixed solvent of 40), and the coating non-volatile content of each composition was measured. The result is
The results are shown in Table 2 below.

Next, using the diluted compositions, coating was performed while rotating the object to be coated at a rotation speed of 10 rpm as described above. Then, while rotating, let stand for 10 minutes.
Drying and baking were performed for 0 minutes, and during baking, rotation was performed at the same speed for 10 minutes after being placed in the drying oven. On the other hand, using the same diluted composition, the object to be coated was simply applied to a stationary vertical surface without rotating at all. And after 10 minutes of natural drying, 140
Baking was performed in a dryer in a vertical state under a condition of ° C./20 minutes.

At this time, the state of occurrence of wrinkles on the coating film, the state of sagging, and the like were comprehensively observed to determine whether the method was legal. The results are collectively shown in Table 2 below. The cured coating film was further subjected to a comparative study of various performances. The results are shown in Table 2 below.

[0073]

[Table 1]

[0074]

[Table 2]

<< Footnotes in Table 1 >>"DN-901S" means "Barnock DN-901S".
S ", which is a polyisocyanate resin manufactured by Dainippon Ink and Chemicals, Inc. “BO-357” is an abbreviation for “Barnock BO-357” and is a block isocyanate resin manufactured by the same company. "HMMM" is an abbreviation for hexamethoxymethylmelamine compound. As the “dissociation catalyst (C-1)”, a monoisopropyl ester of phosphoric acid was used. As the “dissociation catalyst (C-2)”, trifluoromethanesulfonic acid was used. As the "curing catalyst (C-3)", di-n-butyltin dilaurate was used. The numerical values represent the solid content weight.

[0076]

[Table 3]

[0077]

[Table 4]

<< Footnote to Table 2 >> Critical film thickness 1 ... Critical film thickness at which no curling occurs when coating while rotating. 〃2 .............. Limited film thickness that does not cause sideburn when painted on a stationary vertical surface. Sagging limit film thickness 1 Limit film thickness at which no sagging occurs when coating while rotating. 〃2 ......... Limited film thickness that does not cause sagging when painted on a stationary vertical surface. Storage stability: The stability was measured immediately after the preparation of the resin composition (paint) (that is, the initial stability) and the stability after being kept at 50 ° C. for 5 days. Both numbers represent the "seconds" of Ford Cup # 4. Gloss: Displayed with 60-degree specular reflectance (%). Impact resistance: Performed with a 1/2 inch notch and indicated with 500 g / cm 2. Xylene rubbing: The surface condition of the coating film at the time when the number of rubbings reaches 10 is visually judged. Acid resistance: At 60 ° C, 0.5 milliliter (ml) of a 5% sulfuric acid aqueous solution was dropped, and the state of the coated surface was visually judged. Alkali resistance ························································· 判定 判定 判定 ２４ ２４ ２４. The abrasion resistance ...... felt impregnated with 5% aqueous cleanser, and Placing a load of 1.1kg heavy / 2 cm ² (54 kPa), gloss retention after being 30 reciprocally (%) It was displayed. Weather resistance ············ Displayed as gloss retention (%) after 2,000 hours of accelerated weather resistance test using a QUV panel.

[0079]

As described in detail above, the thermosetting resin composition of the present invention comprises, as active ingredients, a low-molecular-weight acrylic resin containing a hydroxyl-blocked functional group as an essential component, and a hydroxyl-containing resin. A polyester oligomer,
It comprises a curing agent having reactivity with a hydroxyl group, and a dissociation catalyst (dissociation accelerator) or a curing catalyst (curing accelerator).

The high solid content resin composition of the present invention and the high solid content type coating material of the present invention having such a constitution are extremely excellent in solubility in an organic solvent. Moreover, due to the generation of hydroxyl groups at the time of coating, drastic increase in viscosity makes it difficult to cause sagging at the time of painting or baking. It has the advantage of being extremely unlikely.

Further, according to the present invention, when coating is performed using a high solid content resin composition having such a configuration and a high solid content type coating material, the object to be coated is rotated at an appropriate speed. It also provides a painting method and a baking method. Therefore, it is extremely effective in improving the smoothness of the coating film.

The baked coating film thus obtained is extremely excellent in solvent resistance, weather resistance, abrasion resistance and the like, which are particularly useful as a top coat for automobiles.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI B05D 7/24 302 B05D 7/24 302V C08G 18/42 C08G 18/42 18/62 18/62 C09D 133/00 C09D 133/00 175/04 175/04 (72) Inventor Yoshiaki Marutani 3-1 Fuchi-machi, Shinchu, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Hiroyuki Uemura 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72 ) Inventor Shinji Sasaki 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Kazuyo Koga 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Pref. Mazda Co., Ltd. (56) References JP-A Sho64 -36641 (JP, A) JP-A-4-132781 (JP, A) JP-A-3-165871 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 33/00 B05D 1/36-1/40 B05D 3/02 B05D 7/24 C08G 18/42 C08G 18/62 C09D 133/00 C09D 175/04 WPI (DIALOG)

Claims (6)

(57) [Claims] 1. An acrylic oligomer (a) having a blocked hydroxyl group, having a number average molecular weight of 1,500 or less, and a hydroxyl group concentration after dissociation of 2.2 mol / 1,000 g or more, An average molecular weight of 1,500 or less, and
A polyester oligomer (b) having a hydroxyl group concentration of 2.0 mol / 1,000 g or more, a curing agent (c) reactive with hydroxyl groups, and a dissociation catalyst or curing catalyst (d),
A high solid content resin composition, which is contained as an essential film-forming component. 2. It has a blocked hydroxyl group as described above,
Acrylic oligomer (a) having a number average molecular weight of 1,500 or less and a hydroxyl group concentration of 2.2 mol / 1,000 g or more after dissociation is at least the following general formula (I):
2. The composition according to claim 1, wherein the concentration of the blocked hydroxyl group is 50% or more with respect to the concentration of the unblocked hydroxyl group, having any one of the structures represented by (III). 3. High solid content resin composition. Embedded image (R ₁ and R ₂ in the formula each have 1 to 1 carbon atoms.
8 represents an alkyl group, a phenyl group or an aryl group, or a hydrogen atom, a chlorine atom or a fluorine atom, which may be the same or different, and R ₃ represents an alkyl group having 1 to 18 carbon atoms, a phenyl group Or an aryl group. ) (In the formula, R ₄ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ₅ represents a cycloalkyl group, an aralkyl group, an aryl group, an alkoxyl group, an alkanoyloxy group, and a carbon atom having 1 to 18 carbon atoms. Represents an alkyl group having 1 to 22 carbon atoms and substituted with at least one atomic group selected from the group consisting of an alkyl group and a halogen atom. (X in the formula is substituted with at least one atomic group selected from the group consisting of an alkoxyl group, an aralkyl group, an aryl group, an aryloxy group, an alkanoyloxy group, an alkyl group having 1 to 10 carbon atoms and a halogen atom. May be substituted or unsubstituted, and has 1 to 18 carbon atoms.
Represents an alkyl group. ) 3. The acrylic oligomer (a),
Polyester oligomer (b) and the curing agent (c)
And the weight ratio of the dissociation catalyst or the curing catalyst (d)
Is an acrylic oligomer (a) 100
The stell oligomer (b) is 11 to 100, a dissociation catalyst or
Is a curing catalyst (d) of 0.001 to 10 and acrylic
Oligomer (a) and polyester oligomer (b)
The curing agent (c) is 52 to 192 based on the total amount of 100.
2. The high solid content resin composition according to claim 1, wherein
object. 4. A high solid content type paint comprising the high solid content resin composition according to claim 1 as a binder. 5. One coat and one bake, two coats and one bake,
A method for coating a paint in a two-coat two-bake, three-coat two-bake, and overcoat system, wherein the high solid content resin composition according to any one of claims 1 to 3 or the high solid content resin according to claim 4 is used. When applying a solid content type paint to an object to be coated, on the vertical surface of the object to be coated, before the coating begins to sag, and until the coating no longer sags, the object to be coated Is rotated about a substantially horizontal axis. 6. One coat and one bake, two coats and one bake,
A method for baking a paint in a two-coat two-bake, three-coat two-bake, and overcoat system, wherein the high-solids resin composition according to any one of claims 1 to 3 or the high-solid content resin according to claim 4 is used. When the solid-type paint is applied to the object to be coated and then baked, on the longitudinal surface of the object to be coated, before the paint starts to sag, and until the paint no longer sags. Meanwhile, the object to be coated is rotated around a substantially horizontal axis to perform coating, and then
A method for baking paint, comprising baking.