JPH0326111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming a coating film, more specifically, a method for forming a strip-shaped coating film with clear parting lines on a transparent plate.
In particular, the present invention relates to a method of forming a coating film using a special colored paint so that the boundary line at the widthwise end portion of the coating film becomes clear. Here, "clear parting line" means that the boundary line at the end in the width direction of the strip-shaped coating film has a sawtooth shape or a linear shape without meandering.

Conventional technology and problems to be solved In recent years, the direct glazing method, in which the window glass is directly attached to the window frame through a sealant, has been adopted on the automobile assembly line, and the method is used to seal the gap between the periphery of the windshield and the window frame of the car body. In order to reduce assembly costs, moldings are installed using the flat mount method on cars, but moldings tend to become thinner due to the demand for a wider field of view during driving and a larger external appearance of the window glass. Since the sealing material for adhering the window glass is seen through from the outside and impairs the appearance, the periphery of the window glass is masked.
Conventionally, such masking has been done by applying an opaque inorganic ceramic paint by screen printing, but due to the need for high-temperature baking of over 700°C, recently silane coupling agents have been used as the main ingredient. A method of applying colored paint is being applied. However, when this colored paint is applied in a band shape to the above-mentioned window glass or other organic plastic transparent plate, it is unclear whether this is due to the viscosity or surface tension of the paint, but the coating film formed is The border lines become irregular, which is undesirable in terms of appearance.

The inventors of the present invention have carried out intensive research to overcome this drawback, and have discovered that by adding a specific amount of hydrophobic anhydrous silica to the above-mentioned colored paint, it is possible to form a strip-shaped coating film with clear parting lines. I was able to complete it.

Structure and Effects of the Invention The present invention provides a coating film characterized in that a colored paint containing 1 to 5% by weight of hydrophobic anhydrous silica is used to form a band-shaped coating film with clear parting lines on a transparent plate. A forming method is provided.

The colored paint used in the present invention is characterized by containing hydrophobic anhydrous silica, and other components are those described in, for example, Japanese Patent Publication No. 57-33318 and Japanese Patent Application Laid-open No. 58-114762. May be adopted. Specifically, (A) a silane coupling agent, preferably an epoxy silane and a silane having a functional group (hydroxyl group, amino group, imino group, mercapto group, etc.) active against epoxy groups [hereinafter referred to as epoxy activated silane]. (B) Silane having active functional groups (hydroxyl group, amino group, imino group, mercapto group, epoxy group, etc.) in the isocyanate group [hereinafter referred to as isocyanate-active silane] [hereinafter referred to as polyisocyanate reaction product], one or more combinations selected from the group of film-forming substances and polyisocyanates, (C) pigment component, (D) hydrophobicity It is composed of anhydrous silica and (E) an organic solvent, and it is particularly preferable to combine two types, a polyisocyanate reaction product and a film-forming substance, in the above-mentioned (B) component.

As the epoxysilane in the above component (A),
γ-glycidoxypropyltrimethoxylan, γ
-glycidoxypropylmethyldimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethylmethyledimethoxysilane, γ-glycidoxypropylmethyldiisopropenoxysilane, etc. One or more of these are used.

The epoxy-active silane in component (A) above includes aminomethyltriethoxysilane, N-(β
-aminoethyl)aminomethyltrimethoxysilane, aminomethylmethyldiethoxysilane, N-
(β-aminoethyl)aminomethyltributoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminoisobutyltrimethoxysilane,
γ-Mercaptopropyltrimethoxysilane, N
-bis(β-hydroxyethyl)-γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane,
N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)
-γ-amino-β-methylpropyltrimethoxysilane, etc., and one or more of these will be explained. Such epoxy-activated silane is usually reacted at a ratio of 0.3 to 1 mole per mole of epoxysilane. The reaction is carried out in an organic solvent such as methyl ethyl ketone at about room temperature.
This can be done by leaving it for about 20 hours, and if necessary, heating it to about 50℃ to remove tertiary amines, metal oxides,
Solvents such as metal salts, water, phenol, and resorcinol may also be used.

Examples of the polyisocyanate in component (B) include trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, lysine diisocyanate methyl ester, tolylene diisocyanate, Desmodyur N (polyisocyanate manufactured by Bayer), Coronate HL (polyisocyanate manufactured by Nippon Polyurethane Co., Ltd.). isocyanate), and one or more of these can be used.

Isocyanate-active silanes to be reacted with the above polyisocyanate include aminomethyltriethoxysilane, N-(β-aminoethyl)aminomethyltrimethoxysilane, aminomethylmethyldiethoxysilane, and N-(β-aminoethyl)aminomethyltrimethoxysilane. Butoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminoisobutyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-bis(β-hydroxyethyl)-γ-aminopropyl triethoxysilane,
N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ
-aminopropylmethyldimethoxysilane, N-
(β-aminoethyl)-γ-amino-β-methylpropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane,
Examples include 3,4-epoxycyclohexylethylmethyldimethoxysilane and γ-glycidoxypropylmethyldiisopropenoxysilane, and one or more of these may be used.

Film-forming substances in component (B) above include polyester resins, chlorinated rubber, polyvinyl chloride resins, polyacrylate resins, silicone resins, epoxy resins, ethylene-vinyl acetate copolymers, etc., and one or two of these may be used. Use seeds or more.

Pigment components for component (C) above include inorganic pigments such as carbon black, lamp black, titanium white, red iron, titanium yellow, zinc white, lead red, cobalt blue, iron black, aluminum powder, etc., and neozabon black RE. , Neo Black RE, Orazol Black CN, Orazol Black Ba (all manufactured by Ciba Geigy), Spiron Blue 2BH
(manufactured by Hodogaya Chemical Co., Ltd.), carbon black is particularly preferred for the purpose of the present invention.

The hydrophobic anhydrous silica of the above component (D) is produced by combining hydrophilic anhydrous silica (silicon dioxide aerosol) obtained by combustion hydrolysis method with dimethyldichlorosilane, etc. to make it exhibit hydrophobic or superhydrophobic properties. Refers to modified products. As specific examples, AEROSIL R972 (hydrophobic), AEROSIL R202 (superhydrophobic), etc. manufactured by Nippon Aerosil Co., Ltd. may be employed. Such hydrophobic anhydrous silica achieves the intended purpose of clarifying the parting line, suppresses the flow of the coating film, so it is possible to secure a film thickness above a certain level, and also eliminates the gloss of the coating film. ,
Prevents surface reflection and relieves discomfort when layering.

Examples of the organic solvent for component (E) above include ketones such as methyl ethyl ketone and acetone, esters such as ethyl acetate and butyl acetate, ethers such as ethyl ether, tetrahydrofuran, and dioxane, toluene, xylene, and methylene chloride. One or more of these may be used.

In the colored paint consisting of the above components (A) to (E), the blending amount of each component may be selected as appropriate, but in particular (D)
It is necessary to consider the hydrophobic anhydrous silica component. That is, the blending amount of hydrophobic anhydrous silica is 1 to 5% (wt%, same hereinafter) based on the total amount of paint components [1 to 4.5% (preferably 1 to 2.5%) in the case of hydrophobicity,
In the case of superhydrophobicity, oil absorption is relatively low, so 0.5
~10% (preferably 1~4.5%)]. If the lower limit is not reached, the intended purpose will not be achieved, and if the upper limit is exceeded, the viscosity of the paint will become too high, which will hinder the coating work. In addition, for ingredients other than (D), usually 100 parts (parts by weight, the same applies hereinafter) of ingredient (A).
Component (B) is selected in the range of 10 to 200 parts, component (E) is selected in the range of 50 to 5,000 parts, and component (C) is selected in the range of 5 to 200 parts per 100 parts of the total amount of paint components excluding component (E). You can choose within the range.

If necessary, conventional additives such as ultraviolet absorbers, glass powder, glass flakes, molecular sieves, powdered silica gel, fillers such as clay, thickeners, dehydrating agents, butyl benzyl phthalate, dioctyl phthalate, dibutyl Appropriate amounts of plasticizers such as phthalate and chlorinated paraffin may be added.

The method for forming a coating film according to the present invention is characterized by using a colored paint containing the above-mentioned hydrophobic anhydrous silica, and by applying this to a transparent plate made of glass or organic plastic using a conventional method. ,
A strip-shaped coating film with clear parting lines can be formed. The coating work may be performed manually, but automation using a robot is particularly preferred.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Preparation of colored paint (primer composition) A 10% solution of γ-glycidoxypropyltrimethoxysilane in methyl ethyl ketone was placed in a reaction vessel.
g and 206 g of a 10% solution of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane in methyl ethyl ketone were added and mixed, and the mixture was heated at 50°C for 20
Leave to stand for a period of time to obtain a solution (A) of the reaction product.

Meanwhile, trimethylhexamethylene diisocyanate (approximately a 1:1 mixture of 2,2,4- and 2,2,4-isomers) is charged to a reaction vessel under a dry nitrogen atmosphere and stannous octate is added. Next, 0.35 equivalents of γ-mercaptopropyltrimethoxysilane are added little by little to the polyisocyanate, while the reaction temperature is kept from rising above 93-99°C. After addition of the above silane, 80
Hold the reaction product solution at ~85 °C for more than 60 min (B)
get.

Next, to 100 parts of the solution (A) prepared above, 10 parts of solution (B), 10 parts of carbon black, 5 parts of acrylic resin, and superhydrophobic anhydrous silica (Nippon Aerosil
A black colored primer composition is prepared by thoroughly stirring and mixing 3 parts of AEROSIL R202 (manufactured by Co., Ltd.) in a closed container.

Formation of a band-shaped coating film A coating means is connected to a manipulator that is controlled to move along the peripheral edge of the windshield of an automobile, and while supplying the primer composition to the means through a pump, the coating is applied to the peripheral edge of the windshield by 30 mm.
Apply with a width.

Comparative Example 1 A primer composition is prepared in the same manner as in Example 1 except that the superhydrophobic anhydrous silica is omitted, and then a coating film is formed.

Comparative Example 2 In Example 1, hydrophilic anhydrous silica (manufactured by Nippon Aerosil Co., Ltd.,
A primer composition is prepared in the same manner except that 3 parts of AEROSIL 300) are used, and then a coating film is formed.

Coating Results In both the primer compositions of Example 1 and Comparative Example 2, the edges of the boundary line in the width direction of the coated film were not disturbed and the parting line was clear. On the other hand, in the case of Comparative Example 1, if the edges in the width direction of the boundary lines of the coating film were exaggerated, they became saw-toothed, and the desired coating film state could not be obtained.

In addition, these primer compositions should be kept in a sealed state.
When the storage stability was evaluated by leaving it in a 40°C temperature tank for 21 days, it was found that Example 1 and Comparative Example 1 were good with almost no increase in viscosity or abnormal appearance.
In Comparative Example 2, gelation occurred as the viscosity increased.

Claims (1)

[Claims] 1. A method for forming a coating film, which comprises using a colored paint containing 0.5 to 10% by weight of hydrophobic anhydrous silica in forming a band-shaped coating film with clear parting lines on a transparent plate. . 2. The method according to item 1 above, wherein the transparent plate is an automobile window glass made of glass or organic plastic. 3. The colored paint contains (a) a silane coupling agent, (b) a reaction product between a polyisocyanate and a silane having a functional group active toward isocyanate groups, (c) a film-forming substance, (d) carbon black, The method according to item 1 above, which comprises (e) hydrophobic anhydrous silica and (f) an organic solvent. 4. The method according to item 1 above, wherein the strip-shaped coating film is formed automatically by a robot.