JP2503477B2 - Metallic finishing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is based on a so-called 2-coat 1-bake system in which a base paint mixed with a metallic pigment is applied, and then a transparent top clear paint is applied again, followed by heat curing. Regarding the metallic finishing method, the purpose thereof is to reduce the gloss 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 cracks.
It is intended to improve so-called weather resistance such as discoloration, fading and blistering, further improve the finished appearance and the like, and maintain it for a long period of 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. If the top coat resin is deteriorated and the gloss of the top coat is reduced, cracks, peeling, etc.
In addition, there is a drawback that blisters and the like tend to occur between the two 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 low 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 with a low refractive index. It is intended to utilize the characteristics of the fluorine-containing resin. 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 provides a metallic finish method in which a metallic pigment-containing base coating is applied, and then a transparent top clear coating is applied to the coated surface, wherein the base coating is an aqueous coating and the top clear coating is a fluoroolefin. It contains as an essential ingredient and has a weight average molecular weight of about
In the presence of a dispersant composed of an organic solvent-soluble fluoropolymer having a fluorine atom content of 5,000 to about 120,000 and a fluorine atom content of about 1 to about 60% by weight, the radical-polymerizable monomer is soluble and the radical-polymerizable monomer is present. Curable coating containing a non-aqueous dispersion (hereinafter abbreviated as "F-NAD") obtained by polymerizing the radical-polymerizable monomer in an organic liquid in which a polymer formed by the body is insoluble Is used for the metallic finishing method.

A feature of the present invention is that, as a top clear coating composition in a two-coat one-bake system, curability is based on a non-aqueous dispersion liquid (F-NAD) containing a fluoropolymer having the above-mentioned fluoroolefin as an essential component as a dispersant. With the use of paints, the above-mentioned object can be achieved as a result.

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,
Excellent performance in weather resistance, water repellency, oil repellency, stain resistance, non-adhesiveness, and low refractive index, which is unique to fluorine-containing resins, and heat resistance, alkali resistance, and adhesion to base coat coatings. It is possible to form an excellent metallic coating film having the inherent thermal, chemical and mechanical properties such as hardness, gloss, 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 excellent properties mainly based on fluorine atoms such as weather resistance, water repellency, oil repellency, stain resistance, non-adhesiveness, and low flexion. The characteristic that a coating film with a deposition rate can be formed is 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, by the reinforcing effect of the polymer particle portion, the coating strength is increased, the stress in the coating film generated over time is absorbed at the interface between the particles and the dispersion stabilizer, and by preventing the stress from increasing, It is possible to disperse the entire coating film without increasing the energy so much 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 and can be maintained for a long period of time. Further, it is possible to almost completely prevent the occurrence of peeling, blistering and the like between the layers of the topcoat coating film and the basecoat coating film.

 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 base paints can be widely used as long as they are water-based 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. Specifically, the curable resin composition is, for example, a thermosetting resin composition composed of an aqueous base resin and a cross-linking agent, and examples thereof include a resin composition which is cross-linked by heating. Here, the water-based base resin may be either a water-soluble resin or a water-dispersed resin, for example, an acrylic resin, a polyester resin, an alkyd resin, an epoxy resin,
Urethane resins and the like, preferably acrylic resins, polyester resins and the like can be mentioned, and these can be used alone or in combination of two or more. Examples of the cross-linking agent include amino resins.

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 are the above resin composition.
It is preferable to add about 1 to 30 parts by weight per 100 parts 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 water-soluble type is obtained by dissolving the above resin composition in deionized water and further dispersing a metallic pigment. The water dispersion liquid type is one in which the particles of the coating resin are dispersed in deionized water, and basically the one produced by a known method using the above resin composition can be used.

<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 specifically contains fluoroolefin as an essential component,
Alkyl vinyl ether, alicycli
c) 1 selected from vinyl ether, hydroxy vinyl ether, olefin, haloolefin, unsaturated carboxylic acid and its ester, and carboxylic acid vinyl ester 1
Weight average molecular weight of 5,000 to 120,000 (number average molecular weight of about 1,00)
0 to 60,000) and a fluorine atom content of 1 to 60% by weight, which is a polymer soluble in an organic solvent at room temperature. The fluoroolefin as a copolymerization component in the fluoropolymer includes tetrafluoroethylene, chlorotrifluoroethylene,
Vinyl fluoride, vinylidene fluoride, etc. are used.

Further, as other copolymerization components, alkyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, n-butyl vinyl ether, etc .; as alicyclic vinyl ether, cyclohexyl vinyl ether and its derivatives; and hydroxy vinyl ether, hydroxybutyl vinyl ether. Etc .; as olefin and haloolefin, ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride and the like; as carboxylic acid vinyl ester, vinyl acetate, n-butyrate, etc .; and as unsaturated carboxylic acid and its ester, Acrylic acid, methacrylic acid,
Unsaturated carboxylic acids such as crotonic acid; and methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, Of acrylic acid or methacrylic acid such as propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc.
C ₁ ~ 18 alkyl esters; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, C ₂ to 8 hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate and the like; esters of unsaturated carboxylic acids.

These radical-polymerizable monomers may be used alone or in combination of two or more, and if necessary, a part of the monomer may be used as another radical-polymerizable monomer. , Vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, and (meth) acrylonitrile may be substituted.

In addition to the above-exemplified monomers, derivatives of the above-mentioned monomers such as carboxylic acid group-containing fluoroolefin and glycidyl group-containing vinyl ether can also be used.

The fluorine-containing polymer had a fluorine atom content of 1%.
Below, the characteristics of the fluoropolymer are not sufficiently exhibited, and
If it exceeds%, the solubility in the organic solvent is lowered.

Further, such a fluorine-containing polymer may be introduced with a polymerizable double bond to achieve grafting with the core portion of dispersed particles. The introduction of the polymerizable double bond is carried out, for example, by using a carboxylic acid group-containing monomer as a copolymerization component of a fluorine-containing copolymer and using a glycidyl group-containing unsaturated monomer (for example, glycidyl methacrylate, glycidyl acrylate) in the carboxyl group. , Allyl glycidyl ether, etc.), but of course, conversely, it can also be carried out by reacting a glycidyl group-containing acrylic copolymer 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 mercapto group, an isocyanate group and a hydroxyl group, and the like. The general conditions under which addition reactions occur between such reactive group combinations are well known, and the temperatures at which those reactions occur are dependent upon the particular combination of reactive groups selected, and by the use of catalysts. It goes without saying that it can be modified.

By the reaction as described above, the dispersion stabilizer resin can have at least 0.1 polymerizable double bonds in one molecule on average.

Of course, in the present invention, the dispersion stabilizer resin may not have a polymerizable double bond, but by the introduction of a polymerizable double bond, a covalent bond is formed between the polymer forming the particles and the dispersion stabilizer, Further improvement in storage stability and mechanical stability of the dispersion can be achieved.

Specific examples of the above-mentioned fluoropolymer include, for example, hydroxyl group-containing organic solvent-soluble "Lumiflon" series (for example, "Lumiflon LF200" weight average molecular weight of about 50,000, manufactured by Asahi Glass Co., Ltd.). (stock),
Organic solvent-soluble fluorinated polymers are also on the market from Central Glass Co., Ltd. and Penwalt Company.

The molecular weight of the fluoropolymer as a dispersion stabilizer is a weight average molecular weight of 5,000 to 120,000 (a number average molecular weight of about 1,000-6.
However, when the molecular weight is less than about 5,000, the dispersed particles are insufficiently stabilized and aggregation and sedimentation easily occur. On the other hand, when the molecular weight exceeds 120,000, the fluoropolymer This causes a decrease in solubility in an organic solvent and a marked increase in viscosity of the dispersion. To produce the fluoropolymer,
It is usually carried out using a radical initiator. Examples of usable radical polymerization initiators include azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylpaleronitrile), benzoyl peroxide, and lauryl. Examples of peroxides include peroxide initiators such as tert-butyl peroctoate, and these polymerization initiators are generally 0.2 to 10 parts by weight, preferably 0.5 to 100 parts by weight per 100 parts by weight of the monomer used for the polymerization. It can be used within a range of 5 wt .. As the reaction type, emulsion polymerization in an aqueous medium or solution polymerization in an organic solvent is generally adopted. Various solvents can be used as the organic solvent,
In addition to aromatic hydrocarbons, alcohols, esters, ketones, glycol ethers, etc., various commercially available thinners can be used. You may use these individually or in mixture of 2 or more types in various ratios. The reaction temperature and reaction pressure are appropriately selected depending on the type of polymerization initiator, solvent type, and reaction mode.

The above-mentioned dispersion stabilizer resin used in the present invention may be used alone or in combination of two or more kinds having different copolymerization compositions and molecular weights. Further, if necessary, other dispersion stabilizers such as It is also possible to use a small amount of butyl etherified melamine-formaldehyde resin, alkyd resin, general acrylic resin or the like.

According to the present invention, at least one radically polymerizable monomer is polymerized in an organic liquid in the presence of the dispersion stabilizer resin as described above.

Although the dispersion polymer particles produced by the polymerization are not substantially dissolved in the organic liquid used for the polymerization, the fluorine-containing resin and the radical-polymerizable monomer are combined with the organic solvent of the dispersion stabilizer resin solution. It includes organic liquids that are good solvents for the body.

Specific examples of such an organic liquid 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, i-butyl 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 thereof include ethylhexyl acetate, which may be used alone or as a mixture of two or more kinds, but generally, they are mainly composed of an aliphatic hydrocarbon, and an aromatic hydrocarbon or the above A combination of such alcohol-based, ether-based, ester-based or ketone-based solvents as described above is preferably used. Furthermore, trichlorotrifluoroethane, metaxylene hexafluoride, tetrachlorohexafluorobutane, etc. can be used if necessary.

The monomer that can be polymerized in the presence of the dispersion stabilizer resin and the organic liquid described above is not particularly limited as long as it is a radically polymerizable unsaturated monomer, and various kinds can be used. The representative ones are as follows.

(A) Ester of acrylic acid or methacrylic acid; for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, methacrylic acid. ethyl, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, C ₁ ~ 18 alkyl esters of acrylic acid or methacrylic acid lauryl methacrylate; glycidyl acrylate, glycidyl methacrylate; allyl acrylate, C ₂ to 8 alkenyl esters of acrylic or methacrylic acid and allyl methacrylate; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropionic Pills acrylate, C ₂ to 8 hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate; allyl oxyethyl acrylate, acrylic acid or C ₃ ~ 18 alkenyloxyalkyl esters of methacrylic acid such as allyloxy methacrylate.

(B) Vinyl aromatic compound: For example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene vinylpyridine.

(C) α, β-ethylenically unsaturated acids: eg acrylic acid, methacrylic acid, itaconic acid.

(D) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone; vinyl acetate, beopa monomer (Ciel chemical product), vinyl propionate,
Vinyl piperate etc.

Particularly preferable among these monomers are monomers or monomer mixtures containing at least 40% by weight of acrylic acid or methacrylic acid ester.

Polymerization of the above monomers is carried out using a radical polymerization initiator. Examples of usable radical polymerization initiators include 2,2-azoisobutyronitrile and 2,2-azobis (2,2
Azo-based initiators such as 4-dimethylpareronitrile; peroxide-based initiators such as benzoyl peroxide, lauryl peroxide, tert-butyl peroctoate, and the like, and these polymerization initiators are generally used for polymerization. Monomer
It can be used within the range of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight.

The amount of the dispersion stabilizer resin used can be varied over a wide range depending on the type of the resin and the like, but generally 5 to 80% by weight based on the total amount of the monomer to be polymerized and the dispersion stabilizer. , Preferably in the range of about 10 to about 60% by weight.

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,
It is 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 top clear paint in the present invention is the above F-NAD.
Can be used as it is, but two or more kinds having different copolymerization compositions and molecular weights may be used in combination,
Further, if necessary, it is possible to use together with a small amount of other dispersion stabilizers such as alkyl etherified melamine-formaldehyde resin, alkyd resin and acrylic resin.

If necessary, a colorant, a plasticizer, a curing agent, etc., which do not impair the metallic feel of the base coat film, may be added. Examples of the colorant include dyes, organic pigments, and inorganic pigments. Known plasticizers include, for example, low molecular weight plasticizers such as dimethyl phthalate and dioctyl phthalate, vinyl polymer plasticizers, polyester plasticizers, and the like. Polymer plasticizers may be used, and these may be used by being mixed in advance with F-NAD, or may be dissolved in, for example, a radical-polymerizable monomer during the production of F-NAD to prepare a dispersion liquid produced. It can also be distributed in the dispersed polymer particles. 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.

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. As long as it does not lose its efficacy by being decomposed into, it is possible to widely use conventionally known ones, for example, benzophenone type, triazole type,
Phenyl salicylate type, diphenyl acrylate type,
An acetophenone type is preferred. 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- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6-pentamethyl-4-piperidyl), 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 water-based base paint is adjusted to 10 to 30 seconds (Ford cup # 4/20 ° C), and this is directly applied to the material (steel plate, aluminum plate, plastic plate, etc.) or a primer, and further Apply to a substrate coated with an intermediate coating paint so that the cured film thickness is 10 to 30μ.
The coating is performed, for example, by spray coating or electrostatic coating. Next, after leaving it at room temperature for several minutes or at 100 ° C or lower, the viscosity of the base coat coating should be adjusted without curing or after curing.
F-NA adjusted to 20-40 seconds (Ford Cup # 4/20 ℃)
Top clear paint with D as the main component is spray painted,
Apply a film thickness of 20 to 50μ by electrostatic coating. Then leave it for a few minutes at room temperature, then at 10-
By heating for 0 minutes to cure both the base coat coating film and the top coat coating film or the top coat coating film, the metallic finish intended by the present invention can be 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. Production Example of Base Coating (B-1): Styrene 20 parts Methyl methacrylate 10 parts Butyl methacrylate 25 parts 2-Ethylhexyl acrylate 30 parts 2-Hydroxyethyl acrylate 10 parts Acrylic acid 5 parts Ethylene with the above monomer composition Solution polymerization is performed using glycol monoethyl ether to produce an acrylic resin with a solid content of 70% and a molecular weight of about 14000, which is neutralized with dimethylethanolamine in an equivalent amount to make it water-soluble, and deionized water is added to the solid content. 55% aqueous solution acrylic resin (A-1)
Was manufactured.

The following metallic base coat 1 was produced using this acrylic resin (A-1).

Acrylic resin (A-1) 75.20 parts Amino resin (* 1) 10.28 parts Aluminum paste (* 2) 12.23 parts Curing catalyst (* 3) 1.00 parts (* 1): Mitsui Toatsu Chemical Co., Ltd. Cymel 303 (* 2) : Toyo Aluminum Co., Ltd. trade name Aluminum paste 1570N (Note 3): Paratoluenesulfonic acid Metallic base coat 1 was diluted with deionized water to a viscosity (Ford cup # 4, 20 ° C, the same applies hereinafter) of 14 seconds.

(B-2): Styrene 5 parts Methyl methacrylate 25 parts Butyl methacrylate 25 parts 2-Ethylhexyl acrylate 25 parts 2-Hydroxyethyl acrylate 17 parts Methacrylic acid 3 parts Resin by the usual emulsion polymerization method with the above monomer composition. Of about 50 000, particle size 0.1-0.3μ, solid content 45%, and emulsion with dimethylethanolamine
Adjust to 8 to stabilize the acrylic resin emulsion (A
E-1) was produced.

The following metallic base coat 2 was produced using this acrylic resin emulsion (AE-1).

Acrylic resin emulsion 177.8 parts John (AE-1) Amino resin (* 1) 20.4 parts Aluminum paste (* 2) 18.5 parts Curing catalyst (* 3) 2.0 parts Metallic base coat 2 was diluted with deionized water to a viscosity of 14 seconds .

(B-3): Acrylic resin (A-1) 72.7 parts Acrylic resin emulsion 88.9 parts John (AE-1) Amino resin (Note 1) 20.4 parts Aluminum paste (Note 2) 18.5 parts Curing catalyst (Note 3) 2.0 Parts Metallic base coat 3 was produced with the above formulation.

2. Production Example of Top Clear Paint (T-1) Synthesis of Dispersion Polymer Liquid A Heptane 102 parts n-Butyl acetate 8 parts Dispersion stabilizer (Lumiflon LF4006 manufactured by Asahi Glass Co., Ltd. weight average molecular weight of about 19000, fluorine atom content of 30) (% By weight) 108 parts was charged into a flask and 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 were added.

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Tertiary-butylperoxy 2-ethylhexanoate 1.5 parts Non-volatile content of the obtained liquid is 47%.

It was a milky white stable low-viscosity polymer dispersion having a viscosity A and a particle size of polymer particles (measured by an electron microscope; the same applies hereinafter) of 0.15 μm. No precipitation or coarse particles were observed even after standing at room temperature for 3 months.

(T-2) Synthesis of Dispersion Polymer Liquid B Heptane 102 parts n-Butyl acetate 8 parts 108 parts of the dispersion stabilizer of Example 1 was placed in a flask and heated to reflux, and the following monomers and polymerization initiator were added for 3 hours. Then, after aging for 2 hours,
26 parts of n-butyl acetate were added.

Styrene 15 parts Methyl methacrylate 17 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Glycidyl methacrylate 20 parts Methacrylic acid 3 parts Tassialy-butyl peroxy 2-ethylhexanoate 1.5 parts Non-volatile content of the obtained liquid is 46% It was a milky white stable low viscosity polymer dispersion having a viscosity B and a particle size of 0.12 μm. 3 at room temperature
No precipitation or coarse particles were found even after standing for a month.

(T-3) Introduction of double bond into dispersion stabilizer 200 parts of "Lumiflon LF400" (nonvolatile matter 50%, acid value 5), 0.8 part of glycidyl methacrylate, 0.02 part of 4-tert-butylpyrocatechol, dimethylaminoethanol 0.1 A reflux reaction was carried out for 5 hours to introduce a copolymerizable double bond into the dispersion stabilizer molecular chain.

The range of decrease in resin acid value was suppressed to within 0.02 so that the number of double bonds introduced per molecular chain was within 1.

Synthesis of dispersion polymer liquid (C) Heptane 80 parts n-Butyl acetate 8 parts The above dispersion stabilizer 130 parts was charged into a flask, heated and refluxed, and the following monomers and polymerization initiator were added dropwise over 3 hours. After aging for 2 hours, 26 parts of n-butyl acetate was added.

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-Hydroxyethyl methacrylate 15 parts Tassialy-butylperoxy 2-ethylhexanoate 1.5 parts Non-volatile content of the obtained liquid is 47%, viscosity D, particle size 0.18 μm It was a milky white stable low-viscosity polymer dispersion. 3 at room temperature
No precipitate or coarse particles were found even after standing for a month.

(T-4) Styrene 15 parts, n-butyl methacrylate 42 parts, 2-
23 parts of ethylhexyl methacrylate, 18 parts of hydroxyethyl methacrylate and 2 parts of acrylic acid were copolymerized in xylol using the polymerization initiator azobisisobutyronitrile, and the heating residue was 50%, the solution acid value was 9.0, the solution viscosity was H,
An acrylic resin solution having a weight average molecular weight of about 16,000 was obtained.

(T-5) Production of Dispersion Stabilizer 40 parts of isobutyl acetate and 40 parts of toluene were 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%, The viscosity was 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-Butyl peroxy 2-ethylhexanoate 1.5 parts The obtained dispersion liquid has a nonvolatile content of 53%, a viscosity B, and particles of polymer particles. It was a milky white stable low viscosity polymer dispersion having a diameter of 0.2 to 0.3 μm. Even when the dispersion was left at room temperature for 3 months, neither precipitates nor coarse particles were observed.

(T-6) Dispersion Stabilizer Solution Used in T-1 Above 100 parts of the resin solid content in the dispersion or the solution obtained in (T-1) to (T-6) above, the amino resin (Note 4) ) Is added to 15 parts (solid content), and 10% is added to 100 parts of the total amount of both resins.
10 parts of UV absorber solution (Note 5) and 5 parts of light stabilizer (Note 6) were blended, and the viscosity was adjusted to 20-40 seconds (Ford cup # 4/20 ° C) with Swazol # 1000 and then cleared. Got the paint.

In addition, the polyisocyanate compound (Note 7) is added 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-6). Add 10 parts of 10% UV absorber solution and 0.5 parts of light stabilizer (Note 8) to 100 parts of resin solid content, then add viscosity with cellosolve acetate for 20-40 seconds (Ford cup # 4/20 ℃). ) Was adjusted to obtain a top clear paint. Among the top clear paints thus obtained, top clear paints containing an amino resin (T-1-AM) to (T-6-AM), and top clear paints containing an isocyanate compound, respectively. (T-1
-NCO) to (T-6-NCO).

(Note 4): Mitsui Toatsu Chemical Co., Ltd. Coban 20SE (n-butanol modified melamine resin) (Note 5): Ciba-Geigy Tinuvin 900 dissolved in xylol (Note 6): Ciba-Geigy Tinuvin 144 10% xylol solution (Note 7): Non-yellowing modified block cyisocyanate DC-2725 manufactured by Nippon Polyurethane Co., Ltd. (Note 8): Sanol LS292 manufactured by Sankyo Co., Ltd. 3. Examples and comparative examples Automobiles are degreased and phosphate chemical treated mild steel plates. Prepare a coated plate coated with epoxy amide-based cationic electrodeposition primer and intermediate coat surfacer, and coat the above base coating on it (15μ film thickness based on the cured coating),
Top clear paint was applied wet-on-wet (30μ film thickness based on the cured coating) and heated at 140 ° C for 30 minutes to cure both coatings simultaneously.

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 weather resistance> QUV accelerated exposure test: Accelerated weather resistance 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 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 abnormality at all ○: Meat bleeding is observed △: Cracks, swelling, etc. occur a little ×: Cracks, swelling, discoloration, etc. occur frequently <Vividness> PGD (Portable Gloss Disrinctness) Image clarity tester <Interlayer 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 coating film △: A little peeling of coating film ×: A lot of coating film was peeled off <Hardness> Pencil for scratch resistance pencil test (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> 0.1 cc of sodium hydroxide (reagent) was dropped onto the coated surface in an amount of 3 cc, and the coated surface was observed after standing at 55 ° C for 4 hours.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobushige Numa 4-17-1, Higashi-Hachiman, Hiratsuka-shi Kansai Pint Co., Ltd. (72) Inventor Yukio Yamaguchi 4--17-1, Higashi-Hachiman, Hiratsuka-shi In-house Examiner Hiroshi Josho

Claims (1)

(57) [Claims] 1. A base paint containing a metallic pigment is applied,
Then, in the metallic finishing method of applying a transparent top clear paint on the coated surface, the base paint is a water-based paint, the top clear paint contains a fluoroolefin as an essential component, a weight average molecular weight of about 5000 ~
In the presence of a dispersion stabilizer consisting of an organic solvent-soluble fluorine-containing polymer having a fluorine atom content of about 120,000 and a fluorine atom content of about 1 to about 60% by weight, the radical-polymerizable monomer is soluble and the radical-polymerizable monomer is soluble. A method of metallic finishing, comprising a curable coating material containing a non-aqueous dispersion obtained by polymerizing the radical-polymerizable monomer in an organic liquid in which the polymer formed by the method is insoluble.