JPH0738969B2 - Metallic finishing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention comprises applying a base paint containing a metallic pigment and then applying a transparent top clear paint,
Regarding the metallic finishing method by the so-called 2 coat 1 bake method of curing by heating, the purpose is to:
Improves so-called weather resistance such as deterioration of gloss, cracks, discoloration, discoloration, blistering, etc. of the coating film due to long-term outdoor exposure, which has been conventionally regarded as a defect of the coating film by the 2-coat 1-baking method, and further improves the finished appearance, And to keep it for a long time.

Conventional technology and its problems Conventionally, in the two-coat one-bake system, the base paint is a thermosetting paint mainly containing acrylic resin, alkyd resin, urethane resin, and the top clear paint is acrylic resin or alkyd. Thermosetting paints containing a resin as a main component are often used, and in order to prevent the metallic pigment in the base paint from migrating into the top clear paint, so-called "metallic unevenness", The base paint and the top clear paint generally used resin compositions having different physical properties and chemical properties, respectively.

However, it is possible to prevent the occurrence of metallic unevenness by changing the properties of the base paint and the top clear paint, but on the other hand, the weather resistance of the coating film formed from such paint decreases, and the coating film is exposed outdoors. When exposed to a long time, the resin of the top coat deteriorates,
There is a drawback in that the top coat coating film is liable to have a decrease in gloss, cracks, peeling and the like, and blister is easily generated between the coating films.

From such a viewpoint, in order to improve the weather resistance of the coating film, a dispersion type fluorine-containing resin coating obtained by dispersing a polyvinylidene fluoride resin powder in an acrylic resin solution or a fluoroolefin, a fluorine-containing vinyl ether and a hydroxyl group-containing vinyl ether. Attempts have also been made to use copolymer solution paints as top clear paints. It has a small intermolecular cohesive force, is chemically stable, has excellent weather resistance, water repellency, oil repellency, stain resistance, exhibits non-adhesiveness, and can form a coating film having a low refractive index. This is an attempt to utilize the characteristics of fluororesins. However, this case also has the following drawbacks.

That is, when the former dispersion type fluorine-containing resin coating material is used as a top clear coating material, the metallic coating, gloss, sharpness, etc. are the same as those of conventional ones because the coating film formed from the coating material has insufficient transparency. However, the effects peculiar to the fluorine-containing resin cannot be sufficiently exhibited, and it is difficult to improve the weather resistance. When the latter fluorocopolymer solution paint is used as a top clear paint, if the amount of the fluoromonomer required to sufficiently exhibit the properties of the fluororesin is blended, other Coating performance, such as heat resistance, adhesion to base coat coating, hardness, thermal and mechanical properties such as impact resistance are reduced, and at the same time the performance that should be originally as a coating and the characteristics based on fluorine atoms are simultaneously It becomes difficult to form a coating film to be provided. Further, the fluorine-containing monomer is
It is extremely expensive as compared with general polymerizable vinyl-based monomers, and therefore, it is important to exert its effect with a necessary minimum amount of compounding.

Means for Solving the Problems The present invention has been made for the purpose of eliminating the above-mentioned drawbacks in the two-coat one-bake system.

That is, the present invention is a metallic finish method of coating a metallic pigment-containing base coating, and then coating a transparent top clear coating on the coated surface, wherein the base coating is an organic solvent type coating or a non-aqueous dispersion type coating, The above top clear paint has the following general formula [In the formula, R represents a hydrogen atom or a methyl group, n represents an integer of 1 to 11, and R _f represents a linear or branched perfluoroalkyl group having 1 to 21 carbon atoms. ] It is a curable coating material containing a non-aqueous dispersion containing a copolymer containing a perfluoroalkyl group-containing (meth) acrylic monomer and a hydroxyl group-containing monomer as a dispersion stabilizer. The present invention relates to a characteristic metallic finishing method.

A feature of the present invention is that, as a top clear coating composition in a two-coat one-bake system, a copolymer containing a perfluoroalkyl group-containing (meth) acrylic monomer represented by the above general formula (1) and a hydroxyl group-containing monomer. The use of a curable coating material containing a non-aqueous dispersion liquid (hereinafter abbreviated as "F-NAD") having a dispersion stabilizer (hereinafter abbreviated as "fluorine-containing polymer") as a main component results The above object of the present invention can be achieved.

According to the method of the present invention, it is possible to form a topcoat coating film having both the properties originally required as a coating film and the properties based on fluorine atoms. That is, it is chemically stable, has excellent weather resistance, water repellency, oil repellency, stain resistance, exhibits non-adhesiveness, and has a low refractive index, which is a unique property of fluorine-containing resins, and heat resistance and alkali resistance. It is possible to form an excellent metallic coating film that has the inherent thermal, chemical or mechanical properties such as adhesion to the base coat coating film, hardness, glossiness, image clarity and impact resistance. . Moreover, the coating film has a significantly improved long-term outdoor exposure property.

The topcoat coating film formed by the method of the present invention has excellent performance as described above because the continuous phase of the coating film formed from F-NAD used in the present invention is mainly a dispersion stabilizer (ie, Therefore, the surface layer of the coating film has mainly fluorine atom-based properties such as weather resistance, water repellency, oil repellency, stain resistance, non-adhesiveness, and low refractive index. The characteristic of being able to form a coating film of high rate will be exhibited. On the other hand, the thermal, chemical and mechanical properties that the coating must have are reinforced by the polymer particle portion of the dispersion. That is,
The reinforcing effect of the polymer particle portion increases the strength of the coating film, and absorbs the stress in the coating film generated over time at the interface between the particles and the dispersion stabilizer, thereby preventing the stress from increasing, and thus the coating film It is possible to disperse the whole energy without increasing it to such a large energy as to cause damage such as cracking. Further, this fluorine atom need only be present in the continuous phase (dispersion stabilizer) and does not need to be present inside the polymer particles in the dispersion liquid. Therefore, a fluorine-containing polymer obtained by conventional solution polymerization is used. Even if the amount of the fluorine-containing monomer used is smaller than that of the solution described above, the same characteristics based on fluorine atoms can be exhibited. That is, it also has an advantage that a coating film that is significantly advantageous in terms of price can be obtained.

Therefore, by using the top clear coating composition of the present invention in a two-coat one-bake system, it is possible to prevent deterioration of gloss of the top coat after long-term exposure, prevent cracks, peeling, blistering, etc., and significantly improve weather resistance. Furthermore, since the water repellency of the topcoat surface can be maintained for a long period of time, it is possible to prevent water from penetrating into the coating film, and also between the topcoat coating film and the basecoat coating film or the basecoat coating film / intermediate coating film. It is also possible to prevent the formation of water pools (blister) between the layers of the film and the undercoat film. In addition, by adding the above-mentioned F-NAD to the top clear paint, the finish appearance such as gloss and image clarity of the metallic coating film by the 2 coat 1 bake method can be remarkably improved.
Moreover, it can be maintained for a long period of time, and furthermore, the occurrence of peeling between the top coat film and the base coat film, blister and the like can be almost completely prevented.

Hereinafter, the method of the present invention will be described more specifically.

<Base paint> This is a paint that is applied to the object to be coated before the top clear paint is applied. As the base paint used in the present invention, conventionally known paints can be widely used as long as they are organic solvent type or non-aqueous dispersion type paints containing a curable resin composition and a metallic pigment as main components.

The curable resin composition is a composition that is cured by three-dimensionally crosslinking reaction and does not substantially contain a fluorine-containing resin. The curable resin composition is specifically a thermosetting resin composition comprising a base resin such as an acrylic resin, a polyester resin, an epoxy resin, a urethane resin and a crosslinking agent (amino resin, blocked polyisocyanate compound, etc.). Room temperature or low temperature (about 140 ° C or less), which is obtained by adding a curing agent such as polyisocyanate compound to the product or the base resin
Examples thereof include a resin composition that is crosslinked by heating. A resin that does not undergo a crosslinking and curing reaction, such as a cellulose acetate butyrate resin, may be further added to these resin compositions.

Examples of the metallic pigment include aluminum powder, copper powder, mica powder, mica powder coated with titanium oxide and iron oxide, MIO (mica iron oxide) and the like. These metallic pigments have the above resin composition 10
It is preferable to add about 1 to 30 parts by weight per 0 part by weight (solid content). Further, a coloring pigment, an extender pigment or the like may be appropriately mixed.

In the base paint of the present invention, the organic solvent solution type is obtained by dissolving the above resin composition in an organic solvent for paint and further dispersing a metallic pigment. The non-aqueous dispersion liquid type is one in which the particles of the coating resin are dispersed in an organic solvent solution of the coating resin (dispersion stabilizer),
Basically, it is possible to use those already produced by a known method using the above resin composition.

In the present invention, when using a non-aqueous dispersion type base coating, compared with the case of using an organic solvent solution type base coating, it is possible to improve the mechanical strength of the coating film by the polymer particles contained therein, interlayer adhesion, The use thereof is preferred because it can further prevent the generation of cracks, peeling, blistering and the like.

<Top clear paint> A paint which is applied on the surface of the base coat to form a transparent paint and is a curable paint containing F-NAD as a main component.

The fluoropolymer used as a dispersion stabilizer of F-NAD is a copolymer containing a perfluoroalkyl group-containing (meth) acrylic monomer and a hydroxyl group-containing monomer represented by the above general formula (1). Is.

As the perfluoroalkyl group-containing (meth) acrylic monomer, those known per se can be used as long as they are included in the above general formula. Among them, it is preferable that n is an integer of 1 to 4 and R _f is a linear or branched perfluoroalkyl group having 1 to 10 carbon atoms. Specific examples of such a fluorine-based monomer include perfluoromethyl methyl acrylate, perfluoromethyl methyl methacrylate, perfluoropropyl methyl acrylate, perfluoropropyl methyl methacrylate, perfluorooctyl undecyl acrylate, and perfluorooctyl undecyl. Methacrylate, perfluoropropylpropyl acrylate, perfluoropropylpropyl methacrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate,
Examples thereof include 2-perfluoroisononylethyl methacrylate, perfluoroisononylmethyl acrylate, and perfluoroisononylmethyl methacrylate. Among these, perfluoromethylmethyl acrylate, perfluoroisononylmethyl methacrylate, and 2-perfluorooctylethyl acrylate. And 2-perfluorooctylethylmethacrylate are particularly suitable. In the present invention, these may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include hydroxyalkyl (C ₂ -C ₈ ) esters of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate. In the present invention, these may be used alone or in combination of two or more.

The fluorine-containing polymer is, for example, a radical polymerization initiator (azo-based, peroxide-based, etc.) in which one or more selected from each of the above-mentioned two components is further allowed to coexist with other monomers if necessary. Is produced by copolymerization in the presence of In the fluoropolymer, the content of the perfluoroalkyl group-containing (meth) acrylic monomer is usually about 1 to 80% by weight, preferably about 20 to 60% by weight, and the content of the hydroxyl group-containing monomer is also included. The ratio is usually about 5 to 40% by weight, preferably about 10 to 30% by weight. As the other monomer which may be coexistent with these monomers, conventionally known ones can be widely used as long as they can be copolymerized with these monomers, for example, carboxylic acids such as acrylic acid and methacrylic acid. Group-containing monomer, N, N
-Dimethylaminoethyl (meth) acrylate, N, N-
Amino monomers such as diethylaminoethyl (meth) acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, Ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate,
Hexyl methacrylate, octyl methacrylate, lauryl methacrylate, and other acrylic monomers such as acrylic acid or methacrylic acid alkyl (C ₁ -C ₁₈ ) esters, and vinyl aromatics such as styrene, α-methylstyrene, and vinyltoluene Examples thereof include compounds, acrylonitrile, methacrylonitrile, crotonic acid, maleic acid, etc. These may be used alone or in combination of two or more. Among such monomers, especially isobutyl methacrylate,
2-Ethylhexyl methacrylate, lauryl methacrylate, n-butyl methacrylate and styrene are preferred.

The fluoropolymer of the present invention has a weight average molecular weight of about 5,000 to
Conveniently, it is in the range of about 100,000 (about 1000 to about 60,000 in number average molecular weight), preferably about 5000 to about 50,000. When the molecular weight is less than about 5,000, the dispersion particles are insufficiently stabilized, tending to cause aggregation and sedimentation,
On the other hand, if the molecular weight exceeds about 100,000, the viscosity of F-NAD becomes extremely high, and it tends to be difficult to handle.

Furthermore, it is advantageous that the fluoropolymer of the present invention has a polymerizable double bond introduced into the molecule. The introduction of the polymerizable double bond is carried out, for example, by using a carboxyl group-containing unsaturated monomer such as acrylic acid or methacrylic acid as a copolymerization component of the above-mentioned fluoropolymer, and using a glycidyl group-containing unsaturated monomer for the carboxyl group. It can be carried out by reacting a monomer (for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, etc.) or by reacting a glycidyl group-containing fluoropolymer with a carboxyl group-containing unsaturated monomer. Other examples of such a combination include an acid anhydride group and a hydroxyl group, an acid anhydride group and a mercaptan group, an isocyanate group and a hydroxyl group, and the like.

It is desirable to introduce at least 0.1 mol of a polymerizable double bond on average into 1 mol of the fluoropolymer by the above reaction. When a polymerizable double bond is introduced into the fluoropolymer, a covalent bond is formed between the polymer forming the dispersed particles and the dispersion stabilizer, and the resulting storage stability of the dispersion liquid. The effect that the mechanical stability and the like can be further improved is exhibited.

The above-mentioned fluoropolymers may be used alone or in combination of two or more having different copolymerization compositions and molecular weights, and if necessary, other dispersion stabilizers such as alkyl etherified melamine. It is also possible to use together with a small amount of formaldehyde resin, alkyd resin, general acrylic resin not containing the monomer of the general formula (1) as a copolymerization component, and the like.

The non-aqueous dispersion compounded in the top clear coating composition of the present invention is obtained by polymerizing a radical-polymerizable monomer in an organic solvent solution of the above-mentioned fluoropolymer which is a dispersion stabilizer. The polymer of the volatile monomer is dispersed in the form of particles in the organic solvent solution.

In the organic solvent used for the polymerization, the dispersion polymer particles produced by the polymerization are not substantially dissolved, but an organic solvent which is a good solvent for the dispersion stabilizer and the radical polymerizable monomer. Is included. Specific examples of such organic solvents include hexane, heptane, octane and other aliphatic hydrocarbons, benzene, toluene, xylene and other aromatic hydrocarbons, alcohol-based, ether-based, ester-based and ketone-based solvents such as isopropyl alcohol. , N-butyl alcohol, isobutyl alcohol, octyl alcohol, cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, methyl isobutyl ketone, diisobutyl ketone, ethyl acyl ketone, methyl hexyl ketone, ethyl butyl ketone, ethyl acetate, isobutyl acetate, acyl acetate, 2- Examples include ethylhexyl acetate, which may be used alone,
It is possible to use a mixture of two or more kinds, but it is preferable to use an aliphatic hydrocarbon as a main component, and to appropriately combine an aromatic hydrocarbon with the above alcohol-based, ether-based, ester-based or ketone-based solvent. Used for. Also, a large amount of the monomer of the general formula (1) (for example, 80% by weight or more)
If necessary, a good solvent for the fluorine-containing polymer, which is relatively insoluble in the contained organic solvent, such as trichlorotrifluoroethane, metaxylenehexafluoride, and tetrachlorohexafluorobutane can also be used if necessary.

The radically polymerizable monomer that is polymerized into particles in the organic solvent solution of the dispersion stabilizer is not particularly limited as long as it is a monomer having a radically polymerizable unsaturated bond, and various types are used. However, the typical ones are as follows.

(I) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate,
Octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc. Acrylic acid or alkyl methacrylate (C ₁ -C ₁₈ )ester;
Glycidyl acrylate, glycidyl methacrylate;
Allyl acrylate, alkenyl (C ₂ -C ₈₎ esters of acrylic acid or methacrylic acid and allyl methacrylate; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxyalkyl acrylate or methacrylate such as hydroxyethyl methacrylate (C ₂ -C ₈₎ esters;
Allyloxyethyl acrylate, alkenyloxyalkyl (C ₃ ~C ₁₈₎ esters of acrylic acid or methacrylic acid and allyl methacrylate.

(Ii) Vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine and the like.

(Iii) α, β-ethylenically unsaturated acids such as acrylic acid, methacrylic acid and itaconic acid.

(Iv) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone; vinyl acetate, veova monomer (shell chemical product), vinyl propionate,
Vinyl pivalate, the monomer of the above general formula (1), and the like.

Among the above-mentioned monomers, preferable ones are monomers selected from the above (i), particularly methyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate,
It is a monomer or monomer mixture containing at least 40% by weight of 2-hydroxyethyl acrylate or the like.

Polymerization of the above monomers is performed using a radical polymerization initiator. Examples of usable radical polymerization initiators include azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide and lauryl. Peroxide,
Examples thereof include peroxide-based initiators such as tert-butyl peroxide, and these polymerization initiators are generally about 0.2 to about 10 parts by weight, preferably about 10 parts by weight, per 100 parts by weight of the radical-polymerizable monomer used for polymerization. It can be used in the range of 0.5 to about 5 parts by weight.

The amount of the dispersion stabilizer used in the F-NAD can be varied over a wide range depending on the type of the stabilizer, etc., but generally it is based on the total amount of the radically polymerizable monomer to be polymerized and the dispersion stabilizer. About 5 to about 80% by weight, preferably about 10 to about 60
A range of weight percent is convenient.

Further, the total concentration of the radically polymerizable monomer and the dispersion stabilizer in the organic solvent is generally about 30 to 70% by weight, preferably about 30 to 60% by weight.

The polymerization can be carried out by a method known per se, and the reaction temperature during the polymerization can be generally within the range of about 60 to about 160 ° C., and the reaction is usually completed in about 1 to about 15 hours. Can be made.

The F-NAD produced by the method described above is extremely excellent in dispersion stability.

The above-mentioned F-NAD can be used as it is in the top clear coating composition of the present invention, but if necessary, a colorant, a plasticizer, a curing agent, etc. are blended to such an extent that the metallic feeling of the base coat film is not impaired. You can also Examples of the colorant include dyes, organic pigments and inorganic pigments, and known plasticizers such as dimethyl phthalate.
Examples thereof include low molecular weight plasticizers such as dioctyl phthalate, high polymer plasticizers such as vinyl polymer plasticizers, polyester plasticizers, etc. These may be mixed in advance with F-NAD or used. At the time of production, it may be dissolved in, for example, a radically polymerizable monomer and then distributed in the dispersion polymer particles of the resulting dispersion. The curing agent is used to crosslink and cure the F-NAD dispersion stabilizer and dispersed particles, and for example, a crosslinking agent such as an amino resin, an epoxy resin, or a polyisocyanate resin can be used. Further, a fibrin-based material, other acrylic resin, alkyd resin, polyester resin, epoxy resin or the like may be blended and used.

In the present invention, an ultraviolet absorber or a light stabilizer may be added to the base paint and / or the top clear paint.
The surface layer of the topcoat coating film in the present invention is mainly composed of a fluoropolymer, so that the weather resistance is remarkably excellent, but ultraviolet rays in the sunlight penetrate such a transparent topcoat coating film, May deteriorate the base coat coating. Therefore, when the base coating material and / or the toff clear coating material contains an ultraviolet absorber and a light stabilizer, not only the top coat coating film but also the weather resistance of the base coating coating film is improved. The purpose of improving the weather resistance of a 2-coat 1-bake metallic coat by blending a fluoropolymer can be largely supplemented. The UV absorber used in the present invention absorbs UV energy and is compatible with or evenly dispersible in the base coating resin and the top clear coating fluoropolymer and is easy at the baking temperature of the coating. Conventionally known compounds can be widely used as long as they do not decompose and lose the effect, and for example, benzophenone type, triazole type, phenyl salicylate type, diphenyl acrylate type, acetophenone type and the like are preferable. Further, by additionally using a light stabilizer in combination with these ultraviolet absorbers, the weather resistance of the base coat coating film and the top clear coating film can be further improved. The light stabilizer is one that is compatible with or evenly dispersible in the base coating resin and the fluorine-containing polymer for top clear coating, and does not lose its effect by being easily decomposed at the baking temperature of the coating. As long as conventionally known ones can be widely used, for example, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,
6,6-Pentamethyl-4-piperidyl) sebacate, 2
Bis (1,2,2,6-pentamethyl-4-piperidyl)-(3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate, tetrakis (2,2,6, 6-Tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6, -pentamethyl-4-piperidyl) -1,2,3,4 -Butane tetracarboxylate and the like. These may be used alone or in combination of two or more.

The blending amount of the ultraviolet absorber is 0.1 to 10% by weight, preferably 1 to 5% by weight based on the resin solid content of the base paint or the top clear paint. The light stabilizer content is 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the resin solid content of the base paint or top clear paint.

<Metallic Finishing Method> The metallic finishing method in the present invention is carried out in the same manner as the conventional method using the above base paint and top clear paint. That is, first, the viscosity of the solution type or non-aqueous dispersion type base paint is adjusted to 10 to 30 seconds (Ford cup # 4/20 ° C), and this is used as a material (steel plate, aluminum plate, plastic plate, etc.). Directly or on a base material coated with a primer or an intermediate coating, the cured film thickness is 10 ~ 30μ
Paint so that. Painting, for example, spray painting,
Perform by electrostatic coating. Next, after leaving it at room temperature for several minutes or at 100 ° C or less, the viscosity of the base coat coating is cured for 20 to 40 seconds (Ford Cup # 4 /
Top clear paint mainly composed of F-NAD adjusted to 20 ℃) is applied by spray coating, electrostatic coating, etc.
Paint to ~ 50μ. Then, after leaving it at room temperature for several minutes, it is heated at 80 to 160 ° C. for 10 to 30 minutes to cure both the base coat coating film and the top coat coating film or the top coat coating film, which is the object of the present invention. A metallic finish is obtained.

Examples The present invention will be further clarified below with reference to Examples and Comparative Examples. In addition, "part" and "%" are based on weight in principle.

1. Manufacturing example of base paint (B-1): Styrene 15 parts, methyl methacrylate 15 parts, butyl methacrylate 40 parts, 2-ethylhexyl acrylate 13
Parts, 15 parts of hydroxyethyl methacrylate and 2 parts of acrylic acid were copolymerized in a xylol using a polymerization initiator azobisisobutyronitrile and a heating residue of 50%, a solution acid value of 8.0, a solution viscosity of Y (Gardner, 25 C) was obtained.

Using this 50% acrylic resin solution, a solvent type base coating material (B-1) was prepared by the following mixing.

50% acrylic resin solution 160 parts 60% amino resin (Note 1) 33 parts Aluminum paste A (Note 2) 12 parts Organic yellow pigment (Note 3) 0.01 parts Carbon black (Note 4) 0.005 parts 10% UV absorber solution -A (Note 5) 10 parts 20% light stabilizer solution-A (Note 6) 5 parts (Note 1): Mitsui Toatsu Chemicals Coban 20SE (n-butanol modified melamine resin) (Note 2): Toyo Aluminum Product name Aluminum Paste 55-519 (Note 3): Ciba Geigy product name Irgadine Yellow
3RCTN (Note 4): Product name Black Pearls 13 manufactured by Cabot
00 (Note 5): Tinubin 900 manufactured by Ciba-Geigy Co., Ltd. dissolved in xylol (Note 6): Sanol LS292 xylol solution manufactured by Sankyo Co., Ltd. Then, this base paint was 40% toluol, Swazol # 1000 (manufactured by Maruzen Oil Co., Ltd.) 30% and The viscosity was adjusted to 14 seconds (Ford cup # 4/20 ° C) with a mixed solvent consisting of 30% butyl acetate.

(B-2): 40 parts of methyl methacrylate, 5 parts of butyl methacrylate
Parts, 40 parts of ethyl acrylate, 13 parts of hydroxyethyl methacrylate and 2 parts of acrylic acid are copolymerized in the xylol using the polymerization initiator azobisisobutyronitrile and the heating residue is 50%, the solution acid value is 8.0 and the solution viscosity is An acrylic resin solution of Y (Gardner, 25 ° C.) was obtained.

Using this 50% acrylic resin solution, a solution type base coating material (B-2) was prepared by the following mixing.

50% acrylic resin solution 160 parts 60% amino resin (Note 1) 33 parts Aluminum paste A (Note 2) 12 parts Organic yellow pigment (Note 3) 0.01 parts Carbon black (Note 4) 0.005 parts 10% UV absorber solution -A (Note 5) 10 parts 20% light stabilizer solution-A (Note 6) 5 parts (B-3): Graft product of poly-12-hydroxystearic acid as a dispersion stabilizer and a methacrylic acid copolymer Using 210 parts, 100 parts of vinyl monomer (a mixture consisting of 30 parts of styrene, 30 parts of methyl methacrylate, 23 parts of 2-ethylhexyl acrylate, 15 parts of hydroxyethyl acrylate and 2 parts of acrylic acid) in n-heptane was used. Dispersion polymerization was carried out by the method to prepare a non-aqueous dispersion liquid. The heating residue was 50% and the degree of dispersion was 20%.

Using this, a non-aqueous dispersion type base paint containing an ultraviolet absorber having the following composition was prepared.

50% non-aqueous dispersion 160 parts 60% amino resin (Note 1) 33.3 parts Aluminum paste (Note 2) 12 parts Organic yellow pigment (Note 3) 0.01 parts Carbon black (Note 4) 0.005 parts 10% UV absorber solution -B (Note 7) 10 parts (Note 7): 2,2 ', 4,4'-Tetrahydroxybenzophenone 10 parts was added to 90 parts of methyl ethyl ketone and dissolved.

Then, this base paint was mixed with 30 parts of an aliphatic hydrocarbon solvent (trade name: Naphthesol # 150, manufactured by Nisseki Chemical Co., Ltd.), 60 parts of cellosolve acetate and 10 parts of carbitol acetate for a viscosity of 14 seconds (Ford Cup # 4 / 20 ° C).

(B-4): Using 210 parts of a graft product of poly-12-hydroxystearic acid and a methacrylic acid copolymer as a dispersion stabilizer, a vinyl monomer (15 parts of styrene, 20 parts of n-butyl acrylate, methyl) Dispersion polymerization of 100 parts of a mixture consisting of 40 parts of methacrylate, 23 parts of hydroxyethyl acrylate and 2 parts of acrylic acid) in n-heptane was carried out by a usual method to prepare a non-aqueous dispersion liquid. 50 heating residue
%, The degree of dispersion was 20%.

Using this, a non-aqueous dispersion type base paint containing an ultraviolet absorber having the following composition was prepared.

50% Non-aqueous dispersion 160 parts 60% Amino resin (Note 1) 33.3 parts Aluminum paste (Note 2) 12 parts Organic yellow pigment (Note 3) 0.01 parts Carbon black (Note 4) 0.005 parts 2. Top clear paint Production Example (T-1): Production of Dispersion Stabilizer 40 parts of isobutyl acetate and 40 parts of toluene are heated to reflux,
The following monomers and polymerization initiators were added dropwise over 3 hours, and after the addition, aging was carried out for 2 hours.

2-perfluorooctylethyl methacrylate 50 parts Styrene 10 parts Isobutyl methacrylate 19 parts 2-Ethylhexyl methacrylate 10 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 2 parts Resin obtained The varnish had a nonvolatile content of 55%, a viscosity (Gardner, 25 ° C., and so on) G and a weight average molecular weight of about 16,000.

Preparation of Non-Aqueous Dispersion Liquid 93 parts of heptane and 98 parts of the dispersion stabilizer obtained above were charged in a flask, heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, and further 2 hours. Aged

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts tert-Butylperoxy 2-ethylhexanoate 1.5
The obtained dispersion liquid has a nonvolatile content of 53%, a viscosity A, and a particle size of polymer particles (measured by an electron microscope, the same applies hereinafter) 0.2 to 0.3 μm
It was a milky white stable low-viscosity polymer dispersion liquid of m. Even after standing at room temperature for 3 months, neither precipitate nor coarse particles were observed.

(T-2): Production of dispersion stabilizer 40 parts of isobutyl acetate and 40 parts of toluene are heated to reflux,
The following monomers and polymerization initiators were added dropwise over 3 hours, and after the addition, aging was carried out for 2 hours.

2-perfluoroisononylmethyl methacrylate 30 parts Styrene 15 parts Isobutyl methacrylate 30 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 1.8 parts The obtained resin varnish is a non-volatile component. It had a viscosity of 55%, a viscosity J and a weight average molecular weight of about 16,000.

Then, add glycidyl acrylate 1.0 to the total amount of the above varnish.
Part, 4-tert-butylpyrocatechol 0.02 part and dimethylaminoethanol 0.1 part were added and the reflux reaction was carried out for 5 hours to introduce a copolymerizable double bond into the dispersion stabilizer molecular chain. The number of introduced double bonds was about 0.8 mol per mol of the molecule as measured by the resin acid value.

Preparation of Non-Aqueous Dispersion Liquid 82 parts of heptane and 121 parts of the dispersion stabilizer obtained above were charged into a flask and heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, and further 2 hours. Aged

Styrene 15 parts Methyl methacrylate 30 parts Acrylonitrile 40 parts 2-Hydroxyethyl methacrylate 15 parts 2,2'-azobisisobutyronitrile 2 parts The obtained dispersion liquid has a nonvolatile content of 55%, a viscosity C, and particles of polymer particles. It was a milky white stable low-viscosity polymer dispersion having a diameter of 0.15 to 0.20 μm. Even after standing at room temperature for 3 months, neither precipitate nor coarse particles were observed.

(T-3): Production of Dispersion Stabilizer 80 parts of meta-xylene hexafluoride was heated and kept at 110 ° C., the following monomers and polymerization initiators were added dropwise in 3 hours, and aging was carried out for 2 hours after the addition. It was

2-perfluorooctylethyl acrylate 50 parts Styrene 30 parts n-Butyl methacrylate 10 parts 2-Hydroxyethyl methacrylate 10 parts 2,2'-azobisisobutyronitrile 2 parts The obtained resin varnish has a nonvolatile content of 55%, The viscosity was C and the weight average molecular weight was about 16,000.

Production of non-aqueous dispersion 20 parts cyclohexane, meta-xylene hexafluoride
62 parts and 121 parts of the dispersion stabilizer obtained above were charged into a flask, heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, followed by aging for 2 hours.

Styrene 15 parts Methyl methacrylate 42 parts Acrylonitrile 20 parts Glycidyl methacrylate 5 parts Acrylic acid 3 parts 2-Hydroxyethyl acrylate 15 parts 2,2'-azobisisobutyronitrile 2 parts The obtained dispersion liquid has a nonvolatile content of 55%, It was a milky white stable low-viscosity polymer dispersion having a viscosity B and a polymer particle size of 0.18 to 0.20 μm. The inside of the particles was crosslinked by the reaction between the epoxy group of glycidyl methacrylate and the carboxyl group of acrylic acid. Even when the dispersion was left at room temperature for 3 months, neither precipitates nor coarse particles were observed.

(T-4): Production of dispersion stabilizer 50 parts of isobutyl acetate and 30 parts of toluene are heated to reflux,
The following monomers and polymerization initiators were added dropwise over 3 hours, and after the addition, aging was carried out for 3 hours.

2-perfluorooctylethyl methacrylate 40 parts Styrene 10 parts Isobutyl methacrylate 19 parts 2-Ethylhexyl methacrylate 10 parts 2-Hydroxyethyl methacrylate 20 parts Methacrylic acid 1 part tert-Butylperoxy 2-ethylhexanoate 3 parts Obtained resin The varnish had a nonvolatile content of 55%, a viscosity G and a weight average molecular weight of about 16,000.

Then 0.8% glycidyl acrylate was added to the total amount of the above varnish.
Part, 4-tert-butylpyrocatechol 0.02 part and dimethylaminoethanol 0.1 part were added and the reflux reaction was carried out for 5 hours to introduce a copolymerizable double bond into the dispersion stabilizer molecular chain. The number of introduced double bonds was about 0.6 mol per mol of the molecule as measured by the resin acid value.

Preparation of Non-Aqueous Dispersion Liquid 93 parts of heptane and 98 parts of the dispersion stabilizer obtained above were charged in a flask, heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, and further 2 hours. Aged

Styrene 10 parts Methyl methacrylate 45 parts Acrylonitrile 25 parts 2-Perfluorooctylethyl methacrylate 5 parts 2-Hydroxyethyl methacrylate 15 parts tert-Butylperoxy 2-ethylhexanoate 1.5
The obtained dispersion was a milky white stable low-viscosity polymer dispersion having a nonvolatile content of 55%, a viscosity H and a particle size of polymer particles of 0.2 to 0.3 μm. This dispersion, even if left at room temperature for 3 months,
No precipitate or coarse particles were found.

(T-5): Production of Non-Aqueous Dispersion 102 parts of heptane, 8 parts of n-butyl acetate and the above (T-
Charge 108 parts of the dispersion stabilizer obtained in 4) into a flask,
The mixture was heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and after aging for 2 hours, 26 parts of n-butyl acetate was added.

Styrene 15 parts Methyl methacrylate 17 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Glycidyl methacrylate 20 parts Methacrylic acid 3 parts tert-Butylperoxy 2-ethylhexanoate 1.5
The obtained dispersion was a milky white stable low-viscosity polymer dispersion having a nonvolatile content of 46%, a viscosity B and a polymer particle size of 0.12 μm. Even after standing at room temperature for 3 months, neither precipitate nor coarse particles were observed.

(T-6): 15 parts of styrene, 42 parts of n-butyl methacrylate, 23 parts of 2-ethylhexyl methacrylate, 18 parts of hydroxyethyl methacrylate and 2 parts of acrylic acid in xylol using the polymerization initiator azobisisobutyronitrile. Copolymerization was performed to obtain an acrylic resin solution having a heating residue of 50%, a solution acid value of 9.0, a solution viscosity of H, and a weight average molecular weight of about 16,000.

(T-7): Production of dispersion stabilizer 40 parts of isobutyl acetate and 40 parts of toluene are heated to reflux,
The following monomers and polymerization initiators were added dropwise over 3 hours, and after the addition, aging was carried out for 2 hours.

Styrene 10 parts Isobutyl methacrylate 69 parts 2-Ethylhexyl methacrylate 10 parts 2-Hydroxyethyl methacrylate 10 parts Methacrylic acid 1 part 2,2'-Azobisisobutyronitrile 2 parts The obtained acrylic resin varnish has a nonvolatile content of 55%, Viscosity H
And the weight average molecular weight was about 16,000.

Preparation of Non-Aqueous Dispersion Liquid 93 parts of heptane and 98 parts of the dispersion stabilizer obtained above were charged in a flask, heated to reflux, and the following monomers and polymerization initiators were added dropwise over 3 hours, and further 2 hours. Aged

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts tert-Butylperoxy 2-ethylhexanoate 1.5
The obtained dispersion was a milky white stable low-viscosity polymer dispersion having a non-volatile content of 53%, a viscosity B and a polymer particle size of 0.2 to 0.3 μm. This dispersion, even if left at room temperature for 3 months,
No precipitate or coarse particles were found.

(T-8): Dispersion stabilizer solution obtained in (T-1) (T-9): Dispersion stabilizer solution obtained in (T-3) above (T-1) to (T- 15 parts (solid content) of amino resin (Note 1) was added to 85 parts of resin solid content in the dispersion or solution obtained in 9), and a 10% UV absorber solution (total of 100 parts of both resins) ( 10 parts of Note 5) and 0.5 part of a light stabilizer (Note 7) were mixed, and the viscosity was adjusted to 20 to 40 seconds (Ford cup # 4/20 ° C) with Swazol # 1000 to obtain a top clear paint.
No amino resin was added to (T-9).

Further, the polyisocyanate compound (Note 9) is blended at a ratio of 1 mol of isocyanate groups to 1 mol of hydroxyl groups in the resin contained in the dispersion or solution obtained in (T-1) to (T-9). Then, 10 parts of a 10% UV absorber solution and 0.5 parts of a light stabilizer (Note 8) were added to 100 parts of the resin solid content, and then a viscosity of 20-40 seconds (Ford cup # 4/20 ° C) was added with cellosolve acetate. To obtain a top clear paint. Incidentally, no isocyanate compound was added to (T-9).

Of the top clear paints thus obtained, the top clear paints containing an amino resin were prepared (T-1
-AM) to (T-8-AM), and top clear coatings containing isocyanate compounds (T-1-NCO) to
(T-8-NCO) is abbreviated.

(Note 8): Tinubin 144 manufactured by Ciba-Geigy (Note 9): Non-yellowing modified block isocyanate DC-2725 manufactured by Nippon Polyurethane Co. 3. Examples and Comparative Examples Degreasing and phosphate chemical treatment on mild steel plate and automotive epoxy Prepare a coated plate coated with amide type cationic electrodeposition primer and intermediate coat surfacer, coat the above base paint on it (15μ film thickness based on the cured coating film), and apply top clear paint wet-on-wet. Both coatings were simultaneously cured by heating at 140 ° C. for 30 minutes (thickness of 30 μm based on the cured coating).

The coating process of these base paints and top clear paints and the performance test results of the resulting coating films are shown in Table 1 below.

The coating film performance test method is as follows.

<Accelerated weathering resistance> QUV accelerated exposure test: Accelerated weathering tester manufactured by Q Panel Co., Ltd. Test conditions: UV irradiation 16 hours / 60 ° C Water agglomeration 8 hours / 50 ° C as one cycle After 5000 hours (208 cycles) test The coating film was tested.

<Gloss> The gloss before and after the accelerated weathering test is specular reflection angle 60 °.
And 20 ° were measured.

<Surface tension> It was measured by a contact angle using water and paraffin.

<Painted state> Determined visually.

◎: No abnormalities ○: Meat stains are observed △: Cracks, blisters, etc. occur a little ×: Cracks, blisters, discoloration, etc. occur frequently <Vividness> PGD (Portable Gloss Disrinctness) Adhesiveness> The coated surface was cross-cut so as to reach the substrate, the adhesive cellophane tape was adhered to the cut portion, and the state of the coated surface after the rapid peeling was visually observed.

◎: Almost no peeling of the coating △: A little peeling of the coating ×: A lot of peeling of the coating <Hardness> Pencil for scratch resistance test pencil (Mitsubishi Uni) <Impact resistance> DuPont impact tester 20 At ℃, place the coated plate on the front side of the hammer tip radius of 1/2 inch with the coated surface facing down, drop 500 g of the falling weight on the surface, and the maximum height (cm) that does not cause abnormalities such as cracks on the coated surface Gasoline> Immerse in Nisseki Super Gasoline (20 ℃) for 24 hours.

<Alkali resistance> Add 3 cc of 0.1N sodium hydroxide (reagent) to the coated surface,
The coated surface was observed after standing at 5 ° C. for 4 hours.

Front page continued (72) Inventor Yutaka Sugiyama 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Kazuhiko Ohira 4-1-1, Higashi-Hachiman, Hiratsuka, Kanagawa Prefecture Company (72) Inventor Yukio Yamaguchi 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Kansai Paint Co., Ltd.

Claims (1)

[Claims] 1. A base paint containing a metallic pigment is applied,
Then, in the metallic finishing method of applying a transparent top clear coating on the coated surface, the base coating is an organic solvent type coating or a non-aqueous dispersion type coating, and the top clear coating is the following general formula: [In the formula, R represents a hydrogen atom or a methyl group, n represents an integer of 1 to 11, and R _f represents a linear or branched perfluoroalkyl group having 1 to 21 carbon atoms. ] It is a curable coating material containing a non-aqueous dispersion containing a perfluoroalkyl group-containing (meth) acrylic monomer and a hydroxyl group-containing monomer as a dispersion stabilizer. Characteristic metallic finishing method.