JPH1113250A - Modesty panel excellent in pollution resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a rain streak stain in a modesty panel, and improve pollution resistance by setting a contact angle of water to a specific value by applying paint by adding an additive to impart a hydrophilic property to a paint film by reaction after forming the paint film, to the modesty panel. SOLUTION: A functional group containing fluororesin is used as a coating film forming resin, and a paint composition 1 is compounded by adjusting the fluororesin concentration to 35 wt.% by adding a polyhydric isocyanate compound as a hardening agent to cross-link/react at the normal temperature with a fluororesin, a polymer of tertamethoxysilane as an additive to impart a hydrophilic property to a paint film by hydrolysis after forming the paint film, aluminum monoacetyl acetonatebis as a catalyst to promote hydrolysis and a butyl acetate as a solvent. When the paint composition 1 is painted on a modesty panel by applying polyurethane white paint to a nonasbestos gypsum board, a contact angle of water of a paint film shows 65 deg. or less, and a rain streak stain is not caused even after six months pass. Therefore, pollution resistance of the modesty panel can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curtain plate excellent in stain resistance.

[0002]

2. Description of the Related Art Siding materials are often used for outer walls of buildings, especially detached houses, for the purpose of simplicity of construction and improvement of design. In addition, buildings using siding materials are boards that are stretched horizontally for the purpose of filling gaps between boards in the vertical direction, or for the purpose of accenting designs, so-called curtain boards (or building trunks, gables, etc.). , Which is sometimes referred to as nakanakashi).

[0003] In addition, in order to prevent dirt, especially dirt that appears in the form of black streaks on the traces of rainwater (hereinafter referred to as rain streak dirt), structural measures such as eaves and caps are taken. Often have. On the other hand, the curtain is 1
It is often installed in the center of a building, such as the middle part of the floor and the second floor. Also, it is often difficult for the curtain plate to escape rainwater in a direction other than the plate surface and flow due to its size, installation purpose, and structure. Accordingly, rain streak stains are generated on the curtain plate portion, often deteriorating the appearance of the building.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. That is, it is an object of the present invention to provide a curtain plate in which generation of rain streak is reduced without being affected by design, structure, construction, and the like.

[0005]

According to the present invention, the contact angle of water is 6 °.
This is a curtain plate on which a hydrophilic coating film of 5 ° or less is formed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

[Curtain Plate] The curtain plate in the present invention is generally called as a curtain plate or a construction frame, and is not particularly limited by its structure, material and the like. The material includes a resin-based material, a metal-based material, and a cement-based material, but a cement-based material is preferably used from the viewpoint of weight, durability, moldability, and the like.

[Method of forming hydrophilic coating film] The contact angle of water is 6
A hydrophilic coating film having a temperature of 5 ° or less can form a hydrophilic coating film by applying a so-called silica sol obtained by hydrolyzing a partial condensate of tetraalkoxysilane and applying a thin silica coating, or by coating. It can be formed by applying a suitable paint.

The following paints are examples of paints capable of forming a hydrophilic coating film having a contact angle of water of 65 ° or less. A paint containing a hydrophilic substance such as polyethylene glycol or a modified product thereof. A paint to which an additive such as a partial condensate of tetraalkoxysilane, which imparts hydrophilicity to a coating film by a reaction after the formation of the coating film, is added. Like compounds obtained by blocking carboxylic acid compounds with fluorinated vinyl ether,
A paint to which a compound that leaves a hydrophilic group on the surface due to decomposition (dissociation) after forming a coating film is added. A paint in which a hydrophilic group (such as a group terminated by a polyethylene glycol chain, a carboxylate or a sulfonate) is introduced into part or all of the film-forming resin.

In consideration of the durability, water resistance, durability of the effect and the like of the coating film, a coating material to which an additive which gives the coating film hydrophilicity by a reaction after forming the coating film, such as a partial condensate of tetraalkoxysilane, is preferable. . When an organic hydrophilic substance is added, the effect may degrade over a long period of time due to decomposition or being washed away by rain. In addition, a film-forming resin in which a hydrophilic group is introduced is not preferred because the water resistance of the coating film is reduced and efflorescence is easily generated.

As the paint to be used, a fluororesin paint is preferred from the viewpoint of weather resistance, and it is particularly preferred that the film-forming resin is a functional group-containing fluororesin from the viewpoint of overall coating performance.

As the functional group-containing fluororesin (a) (hereinafter simply referred to as resin (a)), a wide range can be used without particular limitation, and fluoroolefins known as fluororesins for coatings and copolymerizable with them can be used. The resin (a) obtained by copolymerizing various monomers is preferable from the viewpoint of solubility in a solvent, weather resistance of a coating film, coating workability, and the like.

Examples of the fluoroolefin include C2 or C3 fluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene and pentafluoropropylene.

The monomers copolymerizable with the fluoroolefin include vinyl ether, vinyl carboxylate, allyl ether, allyl carboxylate, isopropenyl ether, isopropenyl carboxylate, methallyl ether, methallyl carboxylate, One or more monomers selected from α-olefins, acrylic esters, methacrylic esters, and the like.

Examples of the vinyl ether include alkyl vinyl ethers such as ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, fluoroalkyl vinyl ether, and perfluoro (alkyl vinyl ether). Examples of the vinyl carboxylate include fatty acid vinyl esters such as Veova-10 (trade name, manufactured by Shell Chemical) having a branched alkyl group, vinyl butyrate, vinyl acetate, vinyl pivalate, and vinyl versatate.

Examples of the allyl ether include alkyl allyl ethers such as ethyl allyl ether and cyclohexyl allyl ether. Examples of the carboxylic acid allyl ester include fatty acid allyl esters such as allyl propionate and allyl acetate. Examples of the isopropenyl ether include an alkyl isopropenyl ether such as methyl isopropenyl ether. Examples of the α-olefin include ethylene, propylene, and isobutylene.

If the copolymerization ratio of the fluoroolefin is too small, sufficiently excellent weather resistance as a weather-resistant paint cannot be exhibited. On the other hand, if the copolymerization ratio of the fluoroolefin is too high, the solubility in a solvent, gloss, pigment dispersibility, and the like are reduced. Therefore, as the resin (a), a resin containing a polymerized unit based on a fluoroolefin in a proportion of 30 to 70 mol%, particularly preferably 40 to 60 mol%, is preferable.

The resin (a) is preferably copolymerized with the above-mentioned compound in addition to the fluoroolefin from the viewpoint of solubility in a solvent and the like. In particular, vinyl ether, vinyl carboxylate, allyl ether and allyl carboxylate are preferred because of their excellent copolymerizability with fluoroolefin. Among them, carbon number 1-10
Alkyl vinyl ethers having a linear, branched or alicyclic alkyl group, fatty acid vinyl esters, alkyl allyl ethers, and fatty acid allyl esters are more preferable.

The resin (a) has a functional group capable of undergoing a cross-linking reaction with the curing agent (b) in addition to the above-mentioned copolymer components, so that a tougher coating film can be obtained. As this functional group,
Examples thereof include an active hydrogen-containing group capable of reacting with an isocyanate-based curing agent and an aminoplast-based curing agent, such as a hydroxyl group, an amino group, an amide group, and a carboxyl group. In addition, functional groups such as an epoxy group, a halogen atom, and a double bond are also exemplified. It is preferably an active hydrogen-containing group, and particularly preferably a hydroxyl group. Further, a fluororesin having a hydrolyzable silyl group such as a trialkoxysilyl group as a functional group can form a three-dimensional crosslinked coating film without using a curing agent.

As a method for introducing such a functional group, a monomer having a functional group other than a double bond participating in polymerization, for example, hydroxybutyl vinyl ether, hydroxybutyl allyl ether, ethylene glycol monoallyl ether, cyclohexanediol mono- Vinyl ether,
There is a method of copolymerizing acrylic acid, methacrylic acid, crotonic acid, undecenoic acid, glycidyl vinyl ether, glycidyl allyl ether, vinyl triethoxysilane, and the like.

A method of introducing a functional group by modifying a copolymer, for example, a method of reacting a hydroxyl group or an epoxy group with a polybasic acid anhydride such as succinic anhydride to introduce a carboxyl group, The functional group can also be introduced by a method of reacting isocyanate alkyl methacrylate or the like to introduce a double bond or a method of reacting isocyanate alkyl trialkoxysilane to introduce a hydrolyzable silyl group. The copolymerized unit having a functional group is
It is preferable to contain 2 to 40 mol% in the copolymer.

Examples of such a fluororesin for paint include Lumiflon (trade name, manufactured by Asahi Glass), Sefral Coat (central glass), Zafflon (trade name, manufactured by Toagosei Chemical Industry),
Commercially available products such as Zeffle (manufactured by Daikin Industries), Fluorate (manufactured by Dainippon Ink and Chemicals), Floren (manufactured by Nippon Synthetic Rubber) and the like can be used.

[Curing Agent (b)] The curing agent (b) is not particularly limited as long as it can crosslink the resin (a).
Examples of those which undergo a crosslinking reaction with the resin (a) at room temperature include polyvalent isocyanate compounds and polybasic acids. In addition, as a curing agent used for baking coating as a one-pack paint,
Examples include aminoplast-based curing agents and blocked isocyanate-based curing agents. This curing agent (b) is a resin (a)
By crosslinking, a cured coating film having excellent physical properties is formed.

As the aminoplast-based curing agent, methylolmelamines, methylolguanamines, methylolureas and the like can be used. Examples of the methylol melamines include methylol melamine etherified with a lower alcohol such as butylated methylol melamine and methylated methylol melamine, and epoxy-modified methylol melamine. Examples of the methylol ureas include alkylated methylol ureas such as methylated methylol urea and ethylated methylol urea. When an aminoplast-based curing agent is used, the addition of an acidic catalyst can promote the crosslinking reaction.

As the blocked isocyanate-based curing agent, there is a blocked product of a polyvalent isocyanate compound.
The polyvalent isocyanate compound is a compound having two or more isocyanate groups, and may be a compound having two or more isocyanate groups, which is a modified or multimeric form thereof.

Examples of the polyvalent isocyanate compound include aliphatic polyvalent isocyanate compounds such as ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, hexamethylene triisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate. Alicyclic polyisocyanate compounds such as diisocyanate methylcyclohexane, and m-xylene diisocyanate, p-
Non-yellowing aromatic isocyanate compounds such as xylene diisocyanate can be exemplified.

Examples of modified polymers and multimers of polyvalent isocyanate compounds include those referred to as urethane-modified, urea-modified, isocyanurate-modified, buret-modified, allophanate-modified and carbodiimide-modified products. is there. In particular, a modified isocyanurate which is a trimer, a modified urethane which is a reaction product with a polyhydric alcohol such as trimethylolpropane, and the like are preferable.

Preferred polyvalent isocyanate compounds include non-yellowing isocyanates such as hexamethylene diisocyanate and isophorone diisocyanate, and multimers thereof.

When a polyvalent isocyanate compound or a blocked isocyanate compound is used, the addition of a known catalyst such as dibutyltin dilaurate can promote the crosslinking reaction.

As the polybasic acid, long chain aliphatic dicarboxylic acids, aromatic polycarboxylic acids and the like are useful, and their acid anhydrides are also useful.

[Additive that gives hydrophilicity to the coating film by reaction after the formation of the coating film] As an additive that imparts hydrophilicity to the coating film by the reaction after the formation of the coating film, a tetrafunctional hydrolyzable silane compound or a polymer thereof is used. preferable. In particular, a multimer is preferable because its function is exhibited by addition of a small amount. A tetrafunctional hydrolyzable silane compound is a compound in which four hydrolyzable groups are directly bonded to a silicon atom. The multimer is obtained by multiplying this compound by condensation (hereinafter, referred to as multimer (c)).

Examples of the hydrolyzable group include an alkoxy group, an alkoxyalkoxy group, an acyloxy group, an aryloxy group, an aminoxy group, an amide group, a ketoxime group, an isocyanate group, and a halogen atom. Preferably, it is a group obtained by removing a hydrogen atom from a hydroxyl group of a monohydric alcohol such as an alkoxy group and an alkoxyalkoxy group. Particularly, an alkoxy group is preferable, and the number of carbon atoms is preferably 4 or less, particularly preferably 1 or 2.

The multimer (c) has a degree of multimerization that does not produce a gel-like product in the composition for a fluorine-containing coating. The multimer (c) is a compound having a degree of multimerization soluble in a solvent or a liquid compound. Here, the degree of multimerization means the number of condensed molecules of the tetrafunctional hydrolyzable silane compound.

The multimers include those having a linear, branched, cyclic, or network structure. Usually, those having a linear structure or those having a linear structure include branched, cyclic, It is considered to be a mixture containing those having a network structure.
As the multimer (c) used in the present invention, those having these structures may be used alone or as a mixture of those having these structures.

The preferred multimer (c) is a multimer of tetraalkoxysilane. If this is shown as having a linear structure, the general formula RO (Si (OR)
₂ O) _n R.

In the general formula, n represents the degree of multimerization of the multimer.
Multimers that are commonly available are mixtures of multimers with different n. In the general formula, R is a lower alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group.
From the viewpoint of hydrolyzability and condensability of the alkoxy group, a polymer of tetramethoxysilane in which R is a methyl group or R
Is a multimer of tetraethoxysilane in which is an ethyl group. A methyl group is particularly preferred from the viewpoint of exhibiting an effect with a small amount and having an effect of preventing the occurrence of rain streak stain without lowering other coating film properties. A plurality of Rs may be different in one molecule.

The degree of multimerization of a tetrafunctional hydrolyzable silane compound such as tetraalkoxysilane and a multimer thereof may be represented by "silica content". “Silica content” refers to the weight ratio of silica (SiO ₂ ) produced from the compound, and is obtained by measuring the amount of silica produced by completely hydrolyzing and calcining the compound.

"Silica content" indicates the ratio of silica generated from one molecule of the compound to one molecule of the compound, and is expressed by the formula [silica content (% by weight) = degree of multiplication × (SiO
₂ ) × 100 / (molecular weight of the compound)].

In the present invention, G is used as the multimer (c).
PC (gel permeation chromatography) by a weight-average molecular weight M _w and the ratio of the number average molecular weight M _n (M _w / M
It is important to use one in which _n ) is 2 or more.

A resin having a small M _w / M _n has a high compatibility with the resin (a) and the curing agent (b). Therefore, unless a relatively large amount of the polymer (c) is blended, an effect of preventing rain streaking can be achieved. Not done. In addition, the multimer (c) remaining inside the coating film has a bad influence on the curability of the coating film, and may lower the solvent resistance and the like and may lower the mechanical properties of the coating film, which is not preferable. . More preferably, M _w / M _n is 2-3.

The molecular weight of the multimer is 500 in _Mn.
As described above, _Mw is preferably 1000 or more. More preferably, _Mn is 500 to 1000, and _Mw
1000 to 3000.

[Solvent (d)] The composition of the present invention can be used together with a solvent (d) capable of dissolving or dispersing the resin (a), the polymer (c) and, if necessary, the curing agent (b).
For example, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as butyl acetate and ethyl acetate, aromatic solvents such as xylene and toluene, furthermore, aliphatic solvents, ether solvents, petroleum solvents, water, etc. Is exemplified. Two or more of these solvents may be used in combination. The composition of the present invention may be one in which the resin (a), the polymer (c) and, if necessary, the curing agent (b) are dispersed in an organic solvent or an aqueous medium.

[Composition ratio] The content of the resin (a), the curing agent (b) and the multimer (c) in the composition of the present invention is such that the curing agent (b) is 0 per 100 parts by weight of the resin (a). The ratio is preferably from 100 to 100 parts by weight, and from 0.1 to 100 parts by weight of the polymer (c). If the content of the curing agent exceeds 100 parts by weight, the workability and impact resistance are undesirably reduced. Particularly preferred ratios are 1 to 50 parts by weight of the curing agent (b) and 1 to 50 parts by weight of the polymer (c) based on 100 parts by weight of the resin (a).

When the resin (a) is a hydroxyl group-containing fluororesin, the content of the blocked isocyanate-based curing agent or polyvalent isocyanate compound is 0.8 mol or more per 1 mol of the hydroxyl group of the hydroxyl group-containing fluororesin. It is preferable to use it. If the amount is less than 0.8 mol, the curing of the coating composition is insufficient, and the solvent resistance and the like may be undesirably reduced. In particular, when the amount is 1.1 mol or more, the effect of preventing generation of rain streak is increased, which is preferable.

The upper limit is not particularly limited, but is preferably 2.0 or less, more preferably 1.2, because unreacted isocyanate groups remain in the coating film and may adversely affect weather resistance and other properties. １1.6.

When the polymer (c) is a polymer of tetramethoxysilane or a polymer of tetraethoxysilane, the content thereof is 1 to 100 parts by weight of the resin (a).
The proportion is preferably 50 parts by weight. Content ratio is 1
If the amount is less than 50 parts by weight, the desired effect of preventing the generation of rain streaks is low.

[Other Compounds] It is considered that the polymer (c) undergoes hydrolysis in the vicinity of the surface of the coating film which can form a hydrophilic coating film formed on the curtain plate surface. A catalyst that promotes this hydrolysis may be used. As such a catalyst, a metal compound catalyst such as a metal chelate, a metal ester, and a metal alkoxide is used. Examples of the metal include aluminum, titanium, silicon, tin, and zinc.

Specific examples include aluminum monoacetylacetonate bis (ethylacetoacetate) and aluminum tris (acetylacetonate). The amount used is 0.1 to 100 parts by weight of the polymer (b).
-20 parts by weight, preferably 1-10 parts by weight.

The coating composition of the present invention may further comprise, in addition to the above components, a curing catalyst, a pigment, an ultraviolet absorber, a light stabilizer, a leveling agent, a matting agent, a surfactant, an anti-sagging agent, and an improvement in adhesion of a coating film. Silane coupling agent or the like may be included. Further, another paint resin such as an acrylic resin, a polyester resin, an epoxy resin, or a silicone resin may be used in combination as long as it does not hinder the generation of rain streaking.

Such a coating composition can be applied by any ordinary coating method, for example, brush coating, roller coating, spray coating, coating with a flow coater, etc., without particular limitation. Further, it may be painted at a factory, or may be painted locally on a curtain plate of a completed building.

[0050]

【Example】

"Example 1 (Example)" A xylene solution (solid content: 60%) of a hydroxyl group-containing fluororesin (copolymer of chlorotrifluoroethylene / cyclohexyl vinyl ether / ethyl vinyl ether / hydroxybutyl vinyl ether = 50/15/25/10 mol%) Weight%, hydroxyl value 50mg KO
H / g) 167 parts by weight of a tetramethoxysilane polymer [silica content 56% by weight, _Mn by GPC of 760,
_Mw of 1820, _Mw / _Mn of 2.4] of 5 parts by weight, and aluminum monoacetylacetonate bis (ethylacetoacetate) of 0.5 part by weight were added and mixed uniformly. 18. Polyvalent isocyanate compound (Coronate-HX manufactured by Nippon Polyurethane: NCO content: 21.3% by weight)
5 parts by weight and butyl acetate were added to reduce the fluororesin concentration to 35.
The composition was adjusted to% by weight to obtain a coating composition (hereinafter referred to as coating composition 1).

A curtain plate made of asbestos-free gypsum board and coated with a polyurethane-based white paint was set on the test wall.
The coating composition 1 was applied to a part of the curtain using a brush. After 3 months, the streak stain was generated on the part of the curtain plate where the coating composition 1 was not coated, but the curtain plate coated with the coating composition 1 did not generate the rain streak even after 6 months. . In addition, the contact angle of water of the coating film on the curtain plate coated with the coating composition 1 was 47 °.

"Example 2 (Example)" A xylene solution of a hydroxyl group-containing fluororesin (copolymer of chlorotrifluoroethylene / cyclohexyl vinyl ether / ethyl vinyl ether / hydroxybutyl vinyl ether = 50/15/25/10 mol%) ( 80 parts by weight of titanium oxide (CR-93 manufactured by Ishihara Sangyo) and 83 parts by weight of butyl acetate were mixed with 167 parts by weight of a solid content of 60% by weight and a hydroxyl value of 50 mg KOH / g, and the mixture was stirred with a paint shaker to obtain a uniform solution. And

To this solution was added a tetramethoxysilane polymer [silica content 59% by weight, _Mn by GPC of 810,
_Mw is 1820, _Mw / _Mn is 2.2] 5 parts by weight, 43 parts by weight of titanium oxide (CR-90 manufactured by Ishihara Sangyo), and 0.5 parts by weight of aluminum monoacetylacetonate bis (ethylacetoacetate). Add and mix homogeneously. Further, a polyvalent isocyanate compound (Coronate-HX manufactured by Nippon Polyurethane Co., NCO content: 21.3% by weight) 18.5
Parts by weight and butyl acetate were added to adjust the fluororesin concentration to 35% by weight, and the coating composition (hereinafter referred to as coating composition 2) was added.
).

An epoxy undercoat material was applied to a curtain plate made of an asbestos-free gypsum board, and a coating composition 2 was applied. The coating was dried at 100 ° C. for 10 minutes, and then placed on a test wall. No rain streaking occurred on this curtain after 6 months. The contact angle of water of the coating film on the curtain plate coated with the coating composition 2 was 46 °.

Example 3 (Comparative Example) For comparison,
A coating composition not containing a multimer of tetramethoxysilane in the coating composition 2 was similarly applied to the test wall. In this curtain plate, rain streak stains were observed after one month, and after three months, rain streak stains became noticeable.

[0056]

According to the present invention, the curtain plate of the present invention does not easily cause rain streaking that impairs the design of the exterior of the building, and the building using this curtain plate can maintain the appearance immediately after the new construction for a long time.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tamyuki Yamano 1-28-10 Hongo, Bungo-ku, Tokyo Asahi Glass Exterior Building Materials Co., Ltd. (72) Inventor Hiromitsu Haraguchi 1-28-10 Hongo, Bunkyo-ku, Tokyo Asahi Glass Exterior Building Materials Co., Ltd.

Claims (5)

[Claims] 1. A curtain plate excellent in stain resistance, on which a hydrophilic coating film having a contact angle of water of 65 ° or less is formed. 2. The curtain plate according to claim 1, wherein the hydrophilic coating film is formed by applying a paint containing a polymer of a tetrafunctional hydrolyzable silane compound. 3. The curtain plate according to claim 2, wherein the tetrafunctional hydrolyzable silane compound is tetramethoxysilane or tetraethoxysilane. 4. The curtain plate according to claim 2, wherein the paint is a fluororesin paint. 5. The paint according to claim 2, wherein the paint is a fluororesin containing a functional group as a film-forming resin.
The curtain plate described in.