JPS63143973A - Film forming method - Google Patents

Abstract

PURPOSE:To enhance the evenness of a coated film, by adjusting the pigment volume concentration of a pigmented coating same as, or very similar to, that of an intercoating with a specific extender pigment and uniforming shrinkage between films in coating a part of a wet film for intercoating with the pigmented coating. CONSTITUTION:A part of a wet film of intercoating I is coated with a pigmented coating II and after both films are heat cured simultaneously, another pigmented coating III is applied on the uncoated part of the pigmented coating II or the whole of cured film, the coating is finished. The coating I is a solution- type heat curable coating comprising a heat-curable resin composition, a color pigment and/or an extender pigment as main components. The pigment volume concentration of the pigmented coating II is adjusted with an extender pigment selected out of talc, clay and barium sulfate so as to be same as or very similar to that of the coating I. By said process, the shrinkage factor of both films at the time of simultaneous heat curing is almost equal, and the generation of unevenness is controlled.

Description

[Detailed description of the invention] The present invention involves coating a part of the wet coating surface with a colored paint,
After heating and curing both coating films at the same time, another colored coating is applied to the unpainted portion of the colored coating or the surface of the colored coating to improve the appearance of the finished coating. Regarding.

As a specific example of the above-mentioned coating method, for example, a colored paint is applied to the desired part of the uncured intermediate coated sheet surface,
There is a so-called two-tone finish in which both coating films are heated and cured at the same time, and then another colored coating is applied to the unpainted portion of the intermediate coat e side. During the painting process for automobile interior and exterior panels that have been coated with a primer such as electrocoated paint, a top coat candy may be applied to the inner panel while the intermediate coating film on the outer panel is wet (uncured). , Splashes (mists) of top-coat colored paint for the inner panel on the intermediate coated surface of the outer panel.
It is easy to paint, and there is also a process in which the paint film is heated and cured in that state, and then a top coat is applied to the entire surface of the intermediate coated surface of the exterior panel. With these methods, uncured wet intermediate coatings are well-known.
The reason for applying colored paint and cutting 7' is to cut costs and improve productivity by omitting the baking process.

However, in the above-mentioned two-tone color finishing and automobile interior and exterior painting processes, color B paint (for example, the first color paint for two-tone color or its mist, or A mist of topcoat paint, etc.) is applied to the inner panel, and after this is heated and cured, other colored paints are applied, such as a second color for two-tone color, a second color for two-tone color, a topcoat for sudden outer panels, etc. ), unevenness occurred in the mist-applied areas and the color boundary areas of the two-tone finish, causing a decrease in smoothness. In order to improve the smoothness, it was also done to polish the uneven parts before applying other colored paints, but this was not practical enough and it was not possible to improve the unevenness. Improvement is strongly desired.

Therefore, the present inventor conducted extensive research with the aim of improving the smoothness of the above-mentioned coating system, and found that some colored paint mist remained on the surface layer of the intermediate coating film that had been polished smooth. When other coloring materials are applied to these painted surfaces, the solvent in the paint swells the intermediate coating film and colored coating @ (mist), and then when baked, the intermediate coating film and colored coating film (mist) are formed. It was determined that the difference in shrinkage rate between the two colors caused unevenness in other colored coatings that were overlaid. In other words, when other colored paints are applied and baked, if the shrinkage rate of the blue paint film (mist) is small, the area will be concave, and if the shrinkage rate is large, the area will be convex, and this will be exposed to the paint surface through the other colored paint film. I guessed that it would happen.

As a result of further research based on these findings, the present inventors found that, for example, in the above coating system, the pigment volume concentration of the colored paint applied to the wet intermediate coating film was determined by using a specific constitutional ω pigment. It has been found that smoothness can be improved by matching or approximating that of the intermediate coating.

That is, the present invention provides a thermosetting resin, a colored pigment, and (
A solution-type thermosetting paint (I) containing an extender pigment (or) as a main component is applied, and then a part of the painted surface is coated with Merck's paint so that the pigment volume concentration is the same as or similar to that of the paint (I). A colored paint (I) prepared with one or more extender pigments selected from clay and barium sulfate is applied, and both coatings are cured simultaneously by heating, and then the paint (II) is applied. The features of the present invention are as follows: When applying the paint (I) to a part of the wet coating film of the paint (+), a specific coating is applied so that the pigment volume concentration (hereinafter referred to as rPVCJ) of the paint (iris) is the same or similar to that of the paint (!). This is because the P of both paints has been adjusted with extender pigments.
If the VC is adjusted, even if the paint (I) is applied to a part of the Unilide film surface of the paint (I), the shrinkage rates of both the paint films will be the same or similar, and the above-mentioned unevenness phenomenon will not occur. There was almost no generation, and the smoothness was significantly improved. In addition, for PVC, it is preferable to mix paint (I) with paint (II), but the present invention is not limited to this, and it is also possible to use paint (I) as a reference or adjust with both paints. do not have.

Next, the coating film forming method of the present invention will be explained in more detail.

Paint (■): A solution-type thermosetting paint mainly composed of a thermosetting resin composition, a colored pigment, and/or an i-type pigment, which is a paint (I) and a paint (I). It is a paint that forms the surface to be coated. Specifically, examples include the above-mentioned two-tone color finish and intermediate coating paints for automobile exterior panels.In addition to these, thermosetting resins include other types of coatings that have special functions in some intermediate coatings. is cross-linked at room temperature or by heating, the main components of which are a base resin selected from alkyd resins, polyester fats, acrylic resins, etc., and a curing agent selected from amine resins, polyisocyanate compounds (including blocked compounds), etc. Curable resin compositions are included, and if necessary, coating resins such as epoxy resins, polycaprolactone, and cyclohexane/dimetatool compounds can also be used in combination.

The coloring pigment is not particularly limited, and examples thereof include hihititanium acid, carbon, red iron oxide, and phthalocyanino. It is particularly preferable to use heavy titanium and a small amount of carbon in the intermediate coating.

In addition, the extender pigment is not particularly limited, and those selected from talc, clay, and barium acid can be used.
Furthermore, anticorrosive pigments such as zinc chromate, zinc white, and strontium chromate can also be applied.

As the pigment for pigment (I), the above-mentioned coloring agent, type 5! Ij′
One or more types selected from pigments and anti-corrosion pigments can be used, and the amount of these pigments can be adjusted depending on the purpose.
Although it is selected, it is preferably 10 to 30%, particularly 15 to 20% in terms of PvC for the intermediate coating.

The PvC of the present invention is the inherent concentration of pigment in the cured coating film of each paint itself. .

The paint (I) is prepared by dissolving or dispersing the above components in an organic solvent, and can be used as a solution, a non-aqueous dispersion type, or a high solids type. It may be applied directly to the object to be coated, such as mechanical equipment or office equipment, or after surface treatment or after coating with a primer such as mold paint (cation type, anion pear). is 15 based on cured coating.
-60μ, especially 20-40μ is preferred. The coating method is not particularly limited and can be carried out by conventional methods such as air spray, airless spray, electrostatic spray, and mini-pernato.

Paint (I): A colored paint that is applied to a part of the coating surface of PvCt-paint (I), and is an extender pigment selected from talc, clay, and barium FA acid to be the same as or similar to PvCt-paint (I). It is necessary to make adjustments.

For example, applying paint (I) to a part of the paint surface of paint (+3) means applying paint (I) to give a two-tone color finish.
) is coated with paint (I) as the first color (after that, apply paint (I) as described below to the unpainted part of paint (Ml).
), the top coat of paint (this corresponds to paint (I)) that is being applied to the inner panel of an automobile is coated with paint (+) and turns into husks or granules to form paint on the outer panel. (+)
The paint (M) is used to finish the paint to the desired color tone. It is a famous color paint that contains coloring pigments, and it is characterized by the fact that PVC is adjusted with a specific extender pigment to be the same or similar to the paint (υ).In other words, the paint (illustration is a vehicle component, Contains eyebrow color pigment and extender pigment as ingredients,
As the vehicle component, the thermosetting resin of the paint (I) is preferable, as the green pigment, an organic or inorganic pigment with a desired color tone can be used, and as the extender pigment, one selected from the three types mentioned above is used. The PVC of Teikoku (I) PVCKPAL, a paint prepared to the desired color tone, is usually 0.5 to 10% USM, and if this is applied directly to the paint (+1 coating surface), the above-mentioned defects will occur. However, in the present invention, the PVC of the paint (I) is made to be the same as that of the paint (+) using an extender pigment, or approximated (within plus or minus 5 of the PVC of the paint (I)).Paint (I) When the PVC of the paint (!) is smaller than that of the paint (!), the paint (I
) is likely to cause dents in the mist area or the color boundary area of two-tone finishing, and if it is larger than 5, the area will protrude, which is not preferable.

Paint (I) can be obtained by dissolving or dispersing each of the above components in an organic solvent.

The coating thickness of the paint (illustration is applied to a part of the uncured coating surface of the paint (I)) is not particularly limited, but for two-tone color finishing, the hardness of the coating is approximately 20 to 40 μm. is particularly preferred.

After applying the paint (I1) on a part of the coated surface of the paint (+), it is heated to harden both coatings. The degree of heating IvA can be arbitrarily selected depending on the composition of the paint, but it is heated at 100 to 200 ° C. 1
0 to 40 minutes is preferred.

Next, in the case of two-tone color finishing, q is the mistake of paint (II) on the paint film boundary area of paint (II) and the painted surface of paint (+) on unpainted areas, and t7'h is the paint on the exterior of the car. (
It is preferable to polish and smooth any convexities caused by the mist of the paint applied to the inner plate that has adhered to the painted surface of the inner plate. After polishing, there is no problem even if the paint (I) embedded in the painted surface remains in spots.

In the present invention, the paint (I) is mainly used after polishing if necessary.
) Paint surface of paint (I) that is not coated (paint (including near the boundary of the paint film of I1), or polished paint (I)
The paint (+) is applied to the coated surface of the paint (+), which has a coating film of The main component is a colored pigment, and the vehicle component can be a thermosetting resin selected from those exemplified in the paint (!), the coloring pigment can be the pigment explained in paint (I), and the PVC is a paint. It is not essential that it be the same as or similar to (I), and it can be used as a solution type, a high solid type, a non-aqueous multi-liquid type, etc. in which these components are dissolved or dispersed in an organic solvent and/or water.

Paint (the thickness of the paint film on the wound is 20 to 40
μ is suitable.

Examples and comparative examples related to the present invention will be described.

Both parts and percentages are based on weight.

! , Sample preparation (I) Zinc phosphate surface treatment (manufactured by Nippon Barker Rising Co., Ltd.)
Mild steel plate (300X3) coated with Bonderite #-144
00x0.8m+) coated with cationic type paint (Kansai Paint Co., Ltd., Elekronna 9600) (cured coating thickness 20μ).

(2) Paint (I) 50% alkyd resin solution (*1) 140 parts Kneepan 2 OS'E (*2) 50 parts titanium oxide (*3) 1o.

A composition consisting of Kijirol/n-butanol (I/1) 17 was adjusted with Sorbetun #150 to have a viscosity of 25 seconds (Ford cup #4/2oC). PVC
was 19.5.

(*1) 1 mole of phthalic anhydride, )! A 50% alkyd resin solution with a hydroxyl value of 85, an oil length of 31%, and an acid value of 7.3, consisting of 1 mol of J methio-propane and 7.5 mol of coconut oil fatty acid.

(*2) Mitsui Toatsu Chemical ■, butanol-modified melamine resin (*3) Sakai Chemical Industry ■ TITONE R-650 (
3) Paint (I) Table 1 (*4) Mitsubishi Chemical ■, Carbon Black MA-10
0B (*S) Titanium Kogyo ■, Mapico Yellow XLO (*6
) Dainichiseika Chemical Industry ■, Corofine Red (*7) Dainichiseika Chemical Industry ■, Phthalocyanine Blue 5 2 4 0K (*8) Sakai Chemical Industry ■, Precipitated FI/ft Barium Acid 1
00 (*9) Engelhard Co, tJ,
A S P-200 (*10) Takehara Chemical Industry ■, Talc No. 1 (4) Paint (II) 50% alkyd resin (*1) 140 parts Kneepan 20SE (*2) 5on organic red pigment (*6) 15/ /Kijirol/n-butanol (I/1) 50=! A paint prepared by adjusting a composition consisting of the following to a spray viscosity of 22 seconds (Ford Cup 8#4/20°C) with Solpetun 4150.

Seals, Examples and Comparative Examples Approximately 30% of paint (I) was applied to the entire surface of the object to be coated to form a cured film.
Paint with air spray to give a μ of about 15 μm at room temperature.
After standing for a few minutes, paint (I) - (I'l-) is applied to a cured film on 1/2 of the surface coated with paint (I) to a thickness of about 20 .mu.m. After leaving it at room temperature for about 10 minutes, it was heated at 140° C. for 30 minutes to cure both coatings at the same time.

Next, mask leaving the boundary part of the paint film of paint (I),
This boundary area and the painted surface of the paint (+) were wet-sanded with #500 waterproof abrasive paper, washed, the mask was removed, air-dried, and then cleaned with petroleum benzene. Mask in the same manner as above, expand the painted surface of paint (I) and the boundary between paint (I) and paint (I) with paint (I1), leave it at room temperature for 10 minutes, and then heat it at 140°C for 30 minutes. I'm sorry for the inconvenience.

The condition of the painted surface of these trial boards was compared. The result is the second
Shown in the table.

Claims (1)

[Claims] A solution-type thermosetting paint (I) containing a thermosetting resin, a color pigment, and/or an extender pigment as the main components is applied, and then a part of the painted surface is coated with a pigment volume concentration of the paint (I). After applying a colored paint (II) prepared with one or more extender pigments selected from talc, clay, and barium sulfate so as to be the same as or similar to that, and curing both coatings simultaneously by heating. , the painted surface of the above paint (I) that is not coated with paint (II) or paint (I) and paint (II)
A coating film forming method characterized by applying a colored paint (I) to both coated surfaces.