JPH0812922A - Method for treating surface of outdoor article - Google Patents

Abstract

PURPOSE:To prevent streaky stain caused by raindrops by treating the surface of a hydrophobic synthetic resin coating film with a surface treatment obtd. by dissolving or dispersing a specific silane compd. alone or together with a synthetic film-forming resin component in an aq. medium to thereby form a thin film on the surface. CONSTITUTION:A silane compd. having silanol groups is produced by stirring a tetrafunctional hydrolyzable silane compd. (e.g. tetraalkoxysilane) with an acid catalyst and water. A surface treatment is prepd. by dispersing 0.01-100 pts.wt. produced silane compd. or 0.01-100 pts.wt. in total of the produced silane compd. and a synthetic film-forming resin component (e.g. a fluororesin) in a wt. ratio of the compd. to the resin component of (1/0.01)-(1/100) and 0.001-100 pts.wt. fluorine surfactant in 100 pts.wt. aq. medium. The treatment is applied to the surface of an outdoor article coated with a hydrophobic synthetic resin (e.g. an acrylic resin), thus forming a 0.01-50mum-thick film to prevent streaky stain caused by raindrops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of surface-treating an outdoor article having a hydrophobic synthetic resin coating film surface, and an outdoor article having a thin film formed by such surface treatment.

[0002]

2. Description of the Related Art Conventionally, products such as metals, inorganic materials, plastics, wood, paper, leather and fibers have been coated with synthetic resin paints for the purpose of protecting them, imparting design characteristics, and imparting functionality. In many cases, surface coating is performed and a hydrophobic synthetic resin coating film is formed on the surface.

Recently, fluororesin paints have been widely used as paints having excellent weather resistance. This fluororesin paint shows much better weather resistance than the synthetic resin paints before that, but the stains on the surface are similar to those of other synthetic resin paints, and its improvement as a highly functional product Is desired.

Particularly, in an article having a hydrophobic synthetic resin coating film used outdoors (hereinafter referred to as an outdoor article), spotted stains due to rainwater are generated on the surface of the hydrophobic synthetic resin coating film exposed to the rain. Cheap. Furthermore, streak-like stains (hereinafter referred to as rain streak stains) are likely to occur in a portion where rainwater gathers and flows, such as under a window frame of a building. Although this rain streak stain can be easily removed by washing, not only is repeated washing complicated, but washing work is not easy for large outdoor articles such as buildings. Therefore, a coated outdoor article having a surface with less generation of rain streaks is desired.

Conventionally, a coating composition containing a polyfluorinated carbon chain and a polymer having a hydrophilic group has been proposed in an attempt to solve the occurrence of stains on the surface of a coated article (Japanese Patent Laid-Open No. 1-198653). ). However, although the effect of suppressing the generation of stains on spots due to rainwater is recognized on the surface coated with this coating composition, it is not sufficient in terms of preventing the generation of rain streak stains.

[0006]

The inventor of the present invention has found a surface treatment agent for preventing the generation of rain streak stains on the surface of an outdoor article having a hydrophobic synthetic resin coating film surface. The present invention provides a novel surface treatment method for the outdoor article using the surface treatment agent, and an outdoor article surface-treated by this method.

[0007]

The present invention is the following invention made to solve the above-mentioned problems.

A silane compound (A) having a silanol group obtained by hydrolyzing a tetrafunctional hydrolyzable silane compound or a multimer thereof or the silane compound (A) and a synthetic resin film-forming component (C) are used as a medium (B). ) And the silane compound (A) is contained in the medium (B) 1
The surface of the coating film of the outdoor article having the hydrophobic synthetic resin coating film is treated with a surface treatment agent in a proportion of 0.01 to 100 parts by weight relative to 00 parts by weight, and the silane compound is applied to the coating film surface. A method for treating an outdoor article surface, which comprises forming a thin film formed from (A) or the silane compound (A) and a synthetic resin film-forming component (C).

A surface treatment agent containing the following silane compound (A) or the following silane compound (A) and a synthetic resin film-forming component (C) on the surface of an outdoor article having a hydrophobic synthetic resin coating film. An outdoor article having the formed thin film, wherein the silane compound (A) is a silane compound (A) having a silanol group formed by hydrolyzing a tetrafunctional hydrolyzable silane compound or a multimer thereof.

The surface treatment method of the present invention is applied to a surface portion of a hydrophobic synthetic resin coating film on which an outdoor article coated with the hydrophobic synthetic resin is particularly susceptible to rain streaks. The thin film formed by this surface treatment can prevent generation of rain streak stains very well for a long time.

The tetrafunctional hydrolyzable silane compound in the silane compound (A) having a silanol group formed by hydrolyzing a tetrafunctional hydrolyzable silane compound or a multimer thereof (hereinafter simply referred to as silane compound A) is a silicon atom. To 4
It is a silane compound in which individual hydrolyzable groups are bonded. The four hydrolyzable groups may be different, but are usually the same hydrolyzable group. Examples of the hydrolyzable group include an alkoxy group, an alkoxyalkoxy group, an acyloxy group, an aryloxy group, an aminoxy group, an amide group,
There are ketoxime groups, isocyanate groups, halogen atoms and the like. Particularly, a group obtained by removing a hydrogen atom from a hydroxyl group of a monohydric alcohol such as an alkoxy group or an alkoxyalkoxy group is preferable. The most preferable hydrolyzable group is an alkoxy group, and the number of carbon atoms thereof is 4 or less, particularly preferably 1 or 2.

As mentioned above, preferred 4 in the present invention.
The functional hydrolyzable silane compound is tetraalkoxysilane, and examples thereof include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxyshishi. Particularly, tetramethoxysilane and tetraethoxysilane are preferable.

The tetrafunctional hydrolyzable silane compound multimer is a multimer produced by condensation of two or more molecules by the reaction of silanol groups produced by hydrolysis of the tetrafunctional hydrolyzable silane compound. The number of condensed molecules of the tetrafunctional hydrolyzable silane compound is hereinafter referred to as the degree of multimerization of the multimer. The degree of multimerization also indicates the number of silicon atoms in one molecule of the multimer. Regarding the multimerization degree of the multimer used in the present invention, if the multimer is too large, it has a high viscosity and is difficult to handle, its solubility in a medium is too low, and it tends to be a gel in a surface treatment agent. Therefore, it is usually 10 or less, and particularly preferably 8 or less.

Multimers of tetrafunctional hydrolyzable silane compounds are generally considered to have a mostly linear molecular structure. However, it is considered that those having a circular, branched, or network molecular structure are also mixed. The multimer used in the present invention may include not only those having such a linear molecular structure but also those having other molecular structures. Hereinafter, the multimer will be described as having a linear molecular structure, but it is not limited thereto.

Tetraalkoxysilane and its multimers (having a linear molecular structure) are RO {Si (OR) ₂
It can be represented by O} _n R. R is an alkyl group,
n represents the degree of multimerization. n is tetraalkoxysilane 1
In the multimer, n is an integer of 2 or more. The normally available multimers are mixtures of multimers with different n, and the degree of multimerization is represented by n averaged.

Further, the degree of multimerization of a tetrafunctional hydrolyzable silane compound such as tetraalkoxysilane and its multimers may be represented by "silica content". The “silica content” means the weight ratio of silica (SiO ₂ ) produced from the compound, and can be obtained by measuring the amount of silica produced by completely hydrolyzing the compound and calcining. Further, "silica content" is intended to indicate the proportion of silica produced from one molecule relative to the compound 1 molecule, wherein [silica content (wt%) = (molecular weight of SiO ₂₎ large amount degree × ×
100 / (molecular weight of the compound)].

By setting the silica content of the tetramethoxysilane polymer to 40% by weight or more and the silica content of the other polymers to 35% by weight or more, it is possible to prevent the generation of rain streaks stains for a long period of time. .

Commercially available tetraalkoxysilane and its multimers can be used. Examples of the multimer include those called methyl silicate 51, ethyl silicate 40, ethyl silicate 48 and the like. The numbers in this product name are said to indicate the value of silica. For example, methyl silicate 51 is a polymer of tetramethoxysilane having a silica content of 51% by weight.

The silane compound A in the present invention is the above-mentioned 4
It is obtained by hydrolyzing a functionally hydrolyzable silane compound or a polymer thereof. A silanol group is generated by the hydrolysis of the hydrolyzable silane compound. However, in the usual case, a condensation reaction due to the silanol group formed accompanying it is also likely to occur. Therefore, when the condensation reaction is likely to occur, it is preferable to use the surface treatment agent within a short time after the hydrolysis is performed from the viewpoint of pot life. As a matter of course, it is possible to use those in which the condensation reaction does not easily occur or those in which the condensation reaction is suppressed. For example, a hydrolysis catalyst or a polymer of hydrolyzed tetraalkoxysilane containing no or a small amount of water can be used.

The hydrolysis reaction is usually carried out by adding a hydrolysis catalyst and water to a tetrafunctional hydrolyzable silane compound or a polymer thereof and stirring the mixture. This hydrolysis may be carried out in the presence of alcohol such as ethanol or isopropyl alcohol. Moreover, you may heat or cool as needed.

The hydrolysis catalyst includes an acid catalyst and a base catalyst, and in many cases an acid catalyst is used. The base catalyst has a high effect of promoting the condensation reaction and cannot be said to be a preferable catalyst in the present invention. As the acid catalyst, those known as hydrolysis catalysts can be used without particular limitation. For example, hydrochloric acid, nitric acid, inorganic acids such as sulfuric acid, acetic acid,
Examples thereof include organic acids such as paratoluenesulfonic acid. In particular, it is preferable to use an inorganic acid such as hydrochloric acid.

As the silane compound A in the present invention, a compound obtained by hydrolyzing a tetraalkoxysilane multimer is most preferable. The multimerization degree of the multimer is preferably from 2 to 10, particularly preferably from 2 to 8. If the degree of multimerization is too high, the solubility in a medium such as water is low as described above, the viscosity of the solution dissolved in the medium is high, the effect of preventing the generation of rain streak stains of interest decreases, and the like. Is not preferable. On the other hand, when the degree of multimerization is 1, that is, when the tetraalkoxysilane is used alone, condensation reaction tends to occur excessively during hydrolysis, and gelation tends to occur. It is difficult to sufficiently achieve the effect of preventing

The tetraalkoxysilane polymer is preferably a tetramethoxysilane polymer or a tetraethoxysilane polymer. Among them, a tetraethoxysilane multimer that is effective even in a small amount and can exert the best effect of preventing rain streak stain generation without deteriorating other physical properties of the coating film is preferable.

The surface treatment agent in the present invention is preferably one in which the silane compound A is dissolved or dispersed in the medium (B). In particular, a uniform solution is preferable for forming a uniform and thin thin film (formed by surface treatment). In addition, an aqueous medium is preferable for reasons such as work stability and environmental conservation, but a non-aqueous medium may be used. As the aqueous medium, basically only water or a mixed medium of water and a water-soluble organic solvent is preferable. Even when the medium is only water, if the hydrolysis for producing the silane compound A is performed in an aqueous medium, a medium containing by-products by-produced by hydrolysis such as alcohol is mixed. As the medium in the present invention, a medium containing such a by-product medium can be used.

As the water-soluble organic solvent, water-soluble alcohols such as ethanol, isopropanol, n-butanol, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether and diacetone alcohol are preferable, and one or more kinds thereof are used. it can.
This organic solvent has a boiling point of 200 ° C. or lower, especially 110
A water-soluble organic solvent having a temperature of ℃ or less is preferable. Those having a too high boiling point are not preferable because they tend to remain in the thin film formed by the surface treatment. Further, for the purpose of accelerating the evaporation of water, a solvent that is azeotropic with water, such as acetone, ethanol,
Isopropyl alcohol or the like can be used.

Examples of the non-aqueous medium include alcohols such as ethanol, isopropanol and n-butanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as butyl acetate and ethyl acetate, aromatic systems such as xylene and toluene. A solvent, an aliphatic solvent, an ether solvent, a petroleum solvent or the like can be used. As such a non-aqueous medium, polar solvents such as alcohols, ketones and esters are preferable. Among the non-aqueous media, alcohols and the like may be mixed with a small amount of water for hydrolysis. These non-aqueous media may be used alone or in combination of two or more.

The content ratio of the silane compound A in the surface treatment agent is 0.01 to 100 with respect to 100 parts by weight of the medium (B).
The ratio of parts by weight is preferable, and more preferably 0.1 to 1.
The ratio is 0 part by weight. If the amount of the silane compound A is too small, a large amount of the treating agent must be used in order to achieve the effect of the surface treating agent, which is not preferable because the coating property is deteriorated. On the other hand, if the amount is too large, the thin film formed becomes too thick and becomes brittle or cracked, which is not preferable. In addition, the silane compound A also has the effect of improving storage stability when diluted in a non-aqueous medium and used.

As the non-aqueous medium, those mentioned above can be used without particular limitation, and alcohols are particularly preferable. When two or more non-aqueous media are mixed and used, at least one of them is preferably an alcohol. The amount of the alcohols used is preferably equivalent to or more than the silane compound A, and more preferably double equivalent or more.

The thickness of the thin film formed by the surface treatment agent is preferably 0.01 to 50 μm, more preferably 0.
It is 1 to 30 μm. Further, a thin film formed by a surface treatment agent which does not use the following synthetic resin film-forming component (C) or which is used in a very small amount easily becomes brittle.
It is preferably 10 μm.

The synthetic resin film-forming component (C) (hereinafter simply referred to as film-forming component C) is used in a proportion of 0.01 to 100 parts by weight, preferably 0.1 to 100 parts by weight, relative to 1 part by weight of the silane compound A.
By compounding the surface treating agent in a ratio of 10 parts by weight, the film forming property of the surface treating agent becomes good, and a tough thin film is formed. Further, the adhesion with the hydrophobic synthetic resin coating film is also improved.

As the film forming component, various resins used as paints such as fluororesin, acrylic resin, acrylic silicone resin, polyester resin, alkyd resin and epoxy resin can be used. Two or more kinds of these resins can be used. As this resin, a so-called fluororesin for paints, which is particularly used for paints, is preferable from the viewpoint of weather resistance. In particular, when the hydrophobic synthetic resin coating film on the outdoor article is a fluororesin coating film, it is preferable from the viewpoint of adhesion with the coating film.

As the fluororesin for paint, a resin composed of one or more polymers of fluoroolefin or a copolymer obtained by copolymerizing fluoroolefin and another copolymerizable monomer is dissolved in a solvent. From the viewpoints of properties, weather resistance of the surface treatment agent coating film, coating workability of the surface treatment agent, film-forming property of the surface treatment agent, and the like. In addition, various solvent-soluble fluororesins for paints such as fluororesins for paints made of vinylidene fluoride polymers or copolymers can be used.
Hereinafter, the fluororesin for coating material made of a fluoroolefin copolymer will be mainly described.

As the fluoroolefin, for example, tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene, pentafluoropropylene and the like having 2 carbon atoms.
Alternatively, a fluoroolefin of 3 may be mentioned. Particularly, tetrafluoroethylene and chlorotrifluoroethylene are preferable. Fluoroolefin-based copolymers include fluoroolefins such as vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymers.
It may be a copolymer of two or more species. However, a copolymer obtained by copolymerizing a fluoroolefin and a copolymerizable monomer other than the fluoroolefin is more preferable.

As the monomer copolymerizable with the fluoroolefin, vinyl ether, vinyl ester, allyl ether, allyl ester, isopropenyl ether, isopropenyl ester, methallyl ether, methallyl ester, α-olefin, acrylic ester,
There are monomers such as methacrylic acid esters. Two or more kinds of these monomers can be used in combination.

The vinyl ether is preferably an alkyl vinyl ether such as ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, (fluoroalkyl) vinyl ether or perfluoro (alkyl vinyl ether). As the vinyl ester, for example, "Veovar having a branched alkyl group
10 "(trade name of Shell Chemical Co.), vinyl pivalate, vinyl versatate, vinyl butyrate, vinyl acetate and other fatty acid vinyl esters are preferred.

Further, the allyl ether is preferably an alkyl allyl ether such as ethyl allyl ether or cyclohexyl allyl ether, and the allyl ester is preferably a fatty acid allyl ester such as allyl propionate or allyl acetate. The isopropenyl ether is preferably an alkyl isopropenyl ether such as methyl isopropenyl ether, and the α-olefin is preferably ethylene, propylene, isobutylene or the like.

If the copolymerization ratio of the fluoroolefin is too low, a sufficiently excellent function as a weather-resistant film-forming component cannot be exhibited. Further, if the copolymerization ratio of the fluoroolefin becomes too large, the solubility in a solvent will decrease, which is not preferable. Therefore, the fluororesin copolymerized with the fluoroolefin in a proportion of 30 to 70 mol%, particularly 40 to 60 mol% with respect to all the monomers is preferable.

Among the above-mentioned monomers copolymerized with the fluoroolefin, vinyl ether, vinyl ester, allyl ether, and allyl ester are particularly preferable because of excellent copolymerizability with the fluoroolefin.
Further, an alkyl vinyl ether having a linear, branched or alicyclic alkyl group having 1 to 10 carbon atoms, a fatty acid vinyl ester, an alkyl allyl ether and a fatty acid allyl ester are preferable.

The fluororesin for paint may have a functional group which is crosslinked by reacting with a curing agent, in addition to the above-mentioned copolymer components. A stronger coating film can be obtained by reacting the fluororesin having this functional group with a curing agent to crosslink it. Examples of this functional group include an active hydrogen-containing group capable of reacting with an isocyanate-based curing agent or an aminoplast-based curing agent, such as a hydroxyl group, an amino group, an acid amide group, or a carboxylic acid group. Other than that, functional groups such as epoxy group, halogen, and double bond are also exemplified.

As a method of introducing such a functional group, a monomer having a functional group, for example, hydroxybutyl vinyl ether, hydroxybutyl allyl ether, ethylene glycol monoallyl ether, cyclohexanediol monovinyl ether, acrylic acid, methacrylic acid, Crotonic acid, undecenoic acid, glycidyl vinyl ether,
There is a method of copolymerizing glycidyl allyl ether or the like.

A method of introducing a functional group by modifying the copolymer, for example, a method of introducing a carboxylic acid group by reacting a hydroxyl group or an epoxy group with a polybasic acid anhydride such as succinic anhydride. Alternatively, a method of reacting an isocyanate alkyl methacrylate or the like to introduce a double bond can be applied.

The content of the copolymerized unit having a functional group is preferably 5 to 20 mol% based on all the copolymerized units in the copolymer.

As the fluororesin as the film-forming component C,
Even if it has a functional group, it is not always necessary to use it together with a component that crosslinks the functional group, that is, a curing agent.
A curing agent, especially a curing agent such as a polyvalent isocyanate compound, easily reacts with other components in the surface treatment agent such as alcohols, water, and silane compound A, so it is used by preliminarily blending in the surface treatment agent. It is often difficult to do. On the other hand, even a fluororesin having a functional group exerts a sufficient effect as the film-forming component C without using a curing agent together. Further, since a fluororesin having a functional group such as a hydroxyl group or a carboxylic acid group has high solubility in a polar solvent such as alcohols, for this reason, even if a curing agent is not used, a fluororesin having a functional group Use is preferred.

Examples of such a fluororesin include Lumiflon (Asahi Glass), Sepral Coat (Central Glass), Zaflon (Toa Gosei), Zeffle (Daikin Industries), Fluoronate (Dainippon Ink Kogyo), Floren (Japan Synthetic Rubber) and Kainer. Commercially available products such as (Atochem) can be used.

As described below, the hydrophobic synthetic resin coating film of the outdoor article is most preferably a coating film formed by coating a fluororesin paint. The above-mentioned fluororesin can be used as the fluororesin for the fluororesin paint. In that case, a fluororesin having a functional group is usually used together with a curing agent. Hereinafter, a curing agent, a compounding agent, and the like for the fluororesin coating material that forms the hydrophobic synthetic resin coating film will be described together with the description regarding the fluororesin as the film-forming component C. Therefore, the description of the curing agent and the like below does not mean that the film-forming component C is essential.

The curing agent is not particularly limited as long as it can crosslink the fluororesin by reacting with the functional group of the fluororesin. Examples of the curing agent used for the fluorine resin having a hydroxyl group include aminoplast type curing agents, isocyanate type curing agents, polybasic acid type curing agents, polyvalent amine type curing agents, and the like.

As the aminoplast type curing agent, methylol melamines, methylol guanamines, methylol ureas and the like can be used. As the methylolmelamines, methylolmelamine etherified with a lower alcohol such as butylated methylolmelamine and methylated methylolmelamine, and epoxy-modified methylolmelamine can be used. As the methylolureas, alkylated methylolureas such as methylated methylolurea and ethylated methylolurea can be used. When an aminoplast-based curing agent is used, an acidic catalyst is usually used to accelerate the crosslinking reaction.

As the isocyanate-based curing agent, there are polyvalent isocyanate compounds and blocked products thereof. 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 product or a multimer thereof.

Examples of the polyvalent isocyanate compound include aliphatic polyvalent isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, hexamethylene triisocyanate and lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diisocyanate methyl. Alicyclic polyvalent isocyanate compounds such as cyclohexane and non-yellowing aromatic polyvalent isocyanate compounds such as xylylene diisocyanate are used.

Examples of modified polymers and polymers of polyvalent isocyanate compounds include those called urethane modified products, urea modified products, isocyanurate modified products, burette modified products, allophanate modified products, and carbodiimide modified products. is there. Particularly preferred are isocyanurate modified products which are trimers and urethane modified products which are reaction products with polyhydric alcohols such as trimethylolpropane.

A coating composition using an isocyanate type curing agent having a free isocyanate group can be cured at room temperature. In particular, it is an almost indispensable curing agent in the case of painting on site. An isocyanate-based curing agent having a blocked isocyanate group is usually a heat-curable coating composition like other curing agents. When an isocyanate-based curing agent is used, a urethanization catalyst such as dibutyltin dilaurate is usually used.

When a curing agent is required in the fluororesin paint for forming the hydrophobic synthetic resin coating film, the mixing amount of the curing agent is 0.1 to 100 parts by weight of the fluororesin resin.
The proportion is preferably 100 parts by weight, particularly 1 to 50 parts by weight.

When the surface treating agent in the present invention is alkaline as described above, the condensation of the silane compound A is promoted, so that the storage stability of the surface treating agent tends to deteriorate. Therefore, the pH is preferably 7 or less. Particularly, from the viewpoint of storage stability, it is preferable to set the pH to about 3 to 4. Therefore, it is preferable to use an acid catalyst for hydrolysis as described above. Further, it is preferable to use a buffer together with the acid catalyst to stabilize the pH.
As the buffering agent, weak acids such as acetic acid and carbonic acid or salts thereof are preferable. The buffer itself may also have an effect as a hydrolysis catalyst. The total amount of these acid catalysts or buffers (D) is 0.001-10 with respect to 100 parts by weight of the medium (B).
It is preferable to use 0 parts by weight, particularly 0.01 to 10 parts by weight.

When an aqueous medium is used in the present invention, it is preferable to use a surfactant (E) together. By adding a surfactant, cissing can be suppressed when a surface treatment agent is applied on the hydrophobic synthetic resin coating film, and a uniform thin film can be formed. The blending amount of the surfactant (E) is appropriately selected depending on the kind of the surfactant and the kind of the hydrophobic synthetic resin coating film. However, it is usually 0.001 to 100 parts by weight, preferably 0.
A proportion of 01 to 10 parts by weight is adopted. Especially as a result,
It is preferable to adjust the type and amount of the surface treatment agent so that the surface tension of the surface treatment agent becomes 30 dyn / cm or less, particularly 20 dyn / cm or less.

The type of surfactant is not particularly limited,
Nonionic ones are preferred. A fluorine-based surfactant having a high surface-active effect even in a small amount is particularly preferable. As the fluorine-based surfactant, for example, a perfluoroalkyl group-containing alkyl ether-based, alkyl ester-based, polyoxyethylene alkylamine-based, polyoxyethylene alkylamide-based fluorine-based surfactant and the like are preferable.

It is also preferable to add a silane coupling agent to the surface treatment agent of the present invention in order to enhance the adhesion to the hydrophobic synthetic resin coating film on the surface of the outdoor article. In the present invention, the silane coupling agent means a silane compound having the above-mentioned hydrolyzable group and other organic group. Organic groups other than hydrolyzable groups are bonded to silicon atoms at terminal carbon atoms. The organic group may be a hydrocarbon group having no functional group, but it is preferable that at least one organic group has a functional group. An alkoxy group is particularly preferable as the hydrolyzable group bonded to the silicon atom, and an isocyanate group is also preferable. Especially 2-3
Silane compounds having one alkoxy group are preferred.

In the above silane coupling agent, the organic group other than the hydrolyzable group has one organic group having a functional group, and when there is another organic group, it is usually a functional group such as an alkyl group. It is usually an organic group having no. Examples of the functional group in the organic group having a functional group include an amino group, an epoxy group, a mercapto group, and an isocyanate group. Particularly, a silane coupling agent having an amino group or an epoxy group is preferable because the adhesion is improved even if the addition amount is small.

The amount of the silane coupling agent is 100 parts by weight of the silane compound A or the silane compound A and the film-forming component C.
1 to 50 parts by weight is suitable for 100 parts by weight in total, and preferably 5 to 30 parts by weight.

The silane coupling agent can be used not only by blending it in the surface treatment agent, but also by treating the hydrophobic synthetic resin coating film on the surface of the outdoor article with a primer in advance. In this case, the silane coupling agent may be applied directly, or may be dissolved in an appropriate solvent such as alcohol or water and applied. A surface treatment is then applied over this primer.

Other than the silane coupling agent, other compounds capable of exhibiting the same effect can be used. Examples of the silane coupling agent and other adhesion improvers include the following compounds.

Methyltrimethoxysilane, dimethylvinylmethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane,
Vinyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-isocyanatopropyltrimethoxysilane, methylsilyltriisocyanate, vinylsilyltriisocyanate, diethoxysilyldiisocyanate, dimethyldichlorosilane, trimethyl Chlorosilane, chloromethyldimethylsilane, methyltrichlorosilane, chloromethyldimethylvinylsilane, hexamethylsilazane, cyclic silazane, N, N-bis (trimethylsilyl) trifluoroacetamide, N-trimethylsilylacetamide, N-trimethylsilylphenylurea, bistrimethylsilylurea, Dimethyl trimethyl silyl amine, trimethyl silyl imidazole, trimethyl silyl dimethyl Amine, methyl triacetoxy silane, 1,3-bis (.gamma.-aminopropyl) -1,1,
3,3-Tetramethyldisiloxane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) Ethyltrimethoxysilane, CH ₃ Si
_{[ON = C (CH 3)} (C 2 H 5)] 3.

Commercially available products are T manufactured by Toshiba Silicone Co., Ltd.
SL8000 series, TSL8100 series, TS
L8300 series, TSL9306, TSL88 series, XC95 series, XC99 series, Shin-Etsu Chemical's KBM1000 series, KBE1000 series, KBC100 series, KBM400, 500, 6
00,700,800,900 series, X-12 series, KBP503 series, AZ manufactured by Nippon Unicar Co., Ltd.
Examples include series, A series, and Union Carbide silane coupling agent A series.

Preferred silane coupling agents are γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane and N- (2-aminoethyl) -γ-aminopropyltriethoxysilane. , N- (2-aminoethyl)
-Γ-aminopropyltrimethoxysilane, N- (2-
Amino group-containing silane coupling agents such as aminoethyl) -γ-aminopropylmethyldimethoxysilane, and 3-glycidoxypropyltrimethoxysilane, 3
-Glycidoxypropylmethyldimethoxysilane, 3-
Glycidoxypropylmethyldiethoxysilane, 2-
An epoxy group-containing silane coupling agent such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

In the present invention, it is considered that the silane compound A is further hydrolyzed or condensed near the surface of the thin film formed by the surface treatment agent on the surface of the hydrophobic synthetic resin coating film. A catalyst that accelerates this reaction can be added to the surface treatment agent. As such a catalyst, a metal chelate,
There are metal compound catalysts such as metal esters and metal alkoxides. The metal component of this catalyst is aluminum,
Examples include titanium, silicon, tin and zinc. Specifically, there are metal compound catalysts such as aluminum monoacetylacetonate bis (ethylacetoacetate) and aluminum tris (acetylacetonate). The amount used is 0.1 to 20 with respect to 100 parts by weight of silane compound A.
A suitable amount is parts by weight, preferably 1 to 10 parts by weight.

The surface treatment agent in the present invention includes, in addition to the above components, a pigment, an ultraviolet absorber, a light stabilizer, a leveling agent,
A matting agent or the like may be included. However, the thin film formed by the surface treatment agent is preferably a transparent thin film. Therefore, it is preferable not to normally use a component such as a pigment that hinders transparency. As a matter of course, even an additive such as a pigment which may impair the transparency can be used within a range not impairing the transparency.

The surface treating agent in the present invention can easily form a uniform thin film by using a usual coating method. The coating method is not particularly limited, and brush coating, roller coating, tampo coating, spray coating, spin coating, flow coating and the like can be used. Further, after application, a thin film is formed only by drying at room temperature, but forced drying may be performed depending on the case.

The surface treating agent in the present invention is used for suppressing the generation of rain streak stains on the surface of a coating film made of a hydrophobic synthetic resin applied to outdoor articles. Rain streaks stains are likely to occur on the hydrophobic surface, and are less likely to occur on the thin film surface formed by this surface treatment agent. Therefore, the surface treatment agent in the present invention is applied to a portion of the outdoor article coated with the hydrophobic synthetic resin, which is exposed to rain and a portion where rainwater flows down. Of course, it may be applied to the peripheral portion at the same time.

As the synthetic resin forming the hydrophobic synthetic resin coating film, there are various hydrophobic resins used as coating materials such as fluororesin, acrylic resin, acrylic silicone resin, polyester resin, alkyd resin and epoxy resin. Two or more kinds of these resins can be mixed and used. As the hydrophobic synthetic resin coating film, a coating film formed of a fluororesin coating material having high hydrophobicity and easily causing rain streak stains has a high necessity of applying the present invention.

In a synthetic resin coating film made of a coating material other than the fluororesin coating material, the thin film formed by the surface treatment agent is easily peeled off because the coating film is easily deteriorated, and the effect of the surface treatment is easily lost. On the other hand, the fluororesin coating film is less likely to be deteriorated as described above and exhibits a sufficient effect which is not the object of the present invention.

As the fluororesin paint, the fluororesin used for the above-mentioned film forming component can be used. Since the surface of the hydrophobic synthetic resin coating film becomes more tough, it is preferable to use a fluororesin coating material containing a functional group-containing fluororesin and a curing agent as basic components. In addition, other types of fluororesin paint may be used.

The present inventor believes that the action of preventing the formation of rain streaks by the thin film formed of the surface treatment agent is basically due to the hydrophilicity and oil repellency of the thin film surface. The oily soil in rainwater adheres to the hydrophobic surface along the stream of rainwater and remains as streaky soil on drying.
On the other hand, since the oily stain does not spread on the hydrophilic and oil-repellent surface, the contact area between the surface and the oily stain becomes narrow. Therefore, the adhesion of the oily stain to the surface is low, and the oily stain easily flows down with the flow of rainwater.

The degree of hydrophobicity-hydrophilicity of the surface can be measured by measuring the octane contact angle in water. The larger the octane contact angle in water, the more hydrophilic the surface and the higher the oil repellency. The present inventor has found that the octane contact angle in water is preferably 102 degrees or more in order to sufficiently prevent the generation of rain streaks. The above-mentioned surface treating agent in the present invention can make the octane contact angle in water of the thin film formed thereby to be 102 degrees or more.

The present inventor has also found that there is a correlation between the advancing tension on the surface and the susceptibility to the formation of rain streaks as well as the octane contact angle. That is, it was found that when the forward tension of the surface is smaller than 0 dyn / cm, rain streak stain is likely to occur, and when it is higher than this, rain streak stain is less likely to occur. Therefore, in order to prevent the generation of rain streaks on the surface of the painted outdoor article, the forward tension of the surface of the thin film formed from the surface treatment agent is set to 0 dyn.
/ Cm or more is preferable. A thin film having such a forward tension has an extremely excellent effect of preventing rain streaks from becoming dirty.

The forward tension of the surface means the tension per unit peripheral length at the time when the sample comes into contact with the water surface when the sample having the thin film formed by the surface treatment agent is immersed in distilled water. When the sample is pulled up from distilled water, it is distinguished from the receding tension which is the tension per unit circumferential length at the time when the sample leaves the water surface.

This advancing tension can be measured using a dynamic contact angle measuring device. Further, since it is difficult to directly measure the advancing tension, the weight change amount (dyn) of the weight change of the sample is measured while the sample is immersed in distilled water at 25 ° C. at a constant rate.
Until the sample comes into contact with the water surface, and the weight change amount at the time when the sample comes into contact with the water surface is determined to obtain the unit perimeter length (c
It is a value determined by dividing by m). In addition, the present inventors adopted the value obtained by measuring at the immersion speed of 20 mm / min as the forward tension.

The material of the base material constituting the outdoor article is not limited. For example, inorganic materials such as concrete, ALC (lightweight cellular concrete), GRC (glass fiber reinforced concrete), CFRC (carbon fiber reinforced concrete), stone, slate, glass, acrylic resin, polycarbonate resin, vinyl chloride resin, polyethylene resin, etc. Synthetic organic materials such as resin and rubber, natural organic materials such as wood, aluminum, copper, brass, titanium, iron,
Metallic materials such as stainless steel, zinc steel plate, steel plate, and F
There are organic-inorganic composite materials such as RP (glass fiber reinforced synthetic resin) and CFRP (carbon fiber reinforced synthetic resin).

The outdoor article in the present invention is an outdoor article having a portion where rain streaks are likely to be stained.
For example, transportation equipment such as automobiles, trains, helicopters, ships, bicycles, snow vehicles, ropeways, lifts, fevercrafts, motorcycles, sashes, shutters, water storage tanks, doors, balconies, outer panels for construction, roofing materials. ,
Building materials such as stairs, skylights, concrete walls, buildings,
Outer walls of buildings such as houses, guardrails, pedestrian bridges, soundproof walls, signs, highway sidewalls, railway viaducts, road members such as bridges, tanks, pipes, towers, plant facilities such as chimneys,
Agricultural equipment such as greenhouses, greenhouses, silos, and agricultural sheets, communication equipment such as utility poles, power transmission towers, parabolic antennas, electrical wiring boxes, lighting equipment, air conditioners, electric equipment such as washing machines, and their covers. , Monuments, tombstones, paving materials, windshields, tarpaulins, and building curing sheets.

Particularly, the present invention is preferably applied to the coated surface of the outer surface of fixed buildings such as buildings and houses and fixed structures such as steel towers and bridges. Most of such fixed structures have a surface on which rainwater flows down, and if the surface is a highly hydrophobic coated surface, rain streak stains are likely to occur. Moreover, many of these fixed structures are large, and repeated cleaning is complicated and requires high cost. Most preferably, the invention applies to such fixed structures.

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, "parts" indicating the ratio of the amount used means parts by weight unless otherwise specified.

[0080]

【Example】

"Surface treatment agent preparation example 1" Ethyl silicate 40 [tetraethoxysilane polymer (average degree of polymerization of about 5) manufactured by Colcoat Co., which does not contain a silanol group] 20 parts to 0.
10 parts of 01N hydrochloric acid was mixed and hydrolyzed at 60 ° C. for 1 hour to obtain a uniform solution containing a silane compound having a silanol group. Water 950 parts, acetic acid 0.5
Part, fluorine-based surfactant C ₈ F ₁₇ CONH (C ₂ H ₄
O) 0.01 parts of ₁₅ CH ₃ was added and stirred to form a uniform solution. This solution is called treating agent 1.

"Surface Treatment Preparation Example 2" A fluororesin having a hydroxyl group (a copolymer of chlorotrifluoroethylene / ethyl vinyl ether / hydroxybutyl vinyl ether, a hydroxyl value of 100 mgKOH / g) was reacted with succinic anhydride to give a hydroxyl group. Partly modified to a carboxyl group (fluorine resin acid value 50 mgKOH / g, hydroxyl value 50
mgKOH / g), and 70% of its carboxyl groups
Was neutralized with ammonia. 0.5 parts of this fluororesin was added to 100 parts of the treating agent 1 and mixed to form a uniform solution.
This solution is called treating agent 2.

"Preparation example 3 of surface treatment agent" 100 of treatment agent 1
0.2 part of γ-aminopropyltrimethoxysilane was added to each part to form a uniform solution. This solution is called treating agent 3.

"Surface Treatment Preparation Example 4" 10 parts of ethyl silicate 40, 50 parts of isopropanol, 0.5 parts of concentrated hydrochloric acid
And 10 parts of ion-exchanged water were mixed and reacted at 60 ° C. for 2 hours while stirring. To this reaction liquid, 200 parts of isopropanol and 230 parts of n-butanol were added and stirred to make a uniform solution. This solution is called treating agent 4.

"Surface Treatment Preparation Example 5" Chlorotrifluoroethylene / undecenoic acid / ethyl vinyl ether / hydroxybutyl vinyl ether (molar ratio 50/10/2
5/15) of a copolymer of isopropyl alcohol (solid content 50% by weight) was added to 2 parts of
A treating agent 5 was obtained by adding 0 parts and mixing.

"Production Example of Specimen" A xylene solution of a fluororesin having a hydroxyl group (chlorotrifluoroethylene / cyclohexyl vinyl ether / ethyl vinyl ether / hydroxybutyl vinyl ether = 50/15/25/10 mol% copolymer) (solid 60 parts by weight, hydroxyl value 50), 100 parts of Coronate HX (isocyanate curing agent from Nippon Polyurethane) as a curing agent, 25 parts of titanium oxide as a pigment, and dibutyltin dilaurate as a curing catalyst of 7 ppm with respect to the resin. The resulting mixture was added and mixed uniformly to produce a fluororesin paint. This fluororesin paint was applied to an aluminum plate of 20 cm × 60 cm and dried at room temperature for 1 week to obtain a test body.

"Example 1, Comparative Example 1" The above-mentioned test bodies were coated with treating agents 1, 2, 3, 4, and 5 so as to have a dry film thickness of 1 to 2 µm, respectively, and dried at room temperature for 1 day. The advancing tension of the surface of the test object by the treatment agent 1 was 32.4 dyn / c.
It was m. The forward tension of the treatment agent 2 is 1
7.6 dyn / cm, with processing agent 4 the forward tension is 2
8.6 dyn / cm, with processing agent 2 advancing tension 2
0.4 dyn / cm, with processing agent 5 advancing tension 2
It was 1.3 dyn / cm. The advancing tension of the surface of the test body on which the treatment agent was not applied was -3.6 dyn / cm.

The sample to be treated and the sample to which the treatment agent was not applied were bent, and the lower part was vertical (30 cm in length),
Outdoor exposure was performed in Kawasaki City with the upper part at 30 degrees (30 cm in length) from the horizontal plane. Once a week on average during exposure 1
There was more than mm mm of rainfall.

In the test body not coated with the treating agent (Comparative Example 1), rain streak stains occurred on the vertical surface after 3 weeks.
However, none of the test bodies coated with the treatment agents 1, 2, 3, 4 or 5 (Example 1) caused rain streaks to stain even after 5 months of exposure.

[Example 2] 10 of ethyl silicate 40
To 0 part, 27 parts of a 0.001% by weight nitric acid aqueous solution and 100 parts of ethanol were added and hydrolyzed at room temperature. In the obtained solution, isopropanol / n-butanol / toluene =
A surface treatment agent 6 was produced by mixing 3200 parts of a solvent having a compounding ratio (weight ratio) of 1/1/1 and 0.1 part of acetylacetone. The surface treatment agent 6 was overcoated on a part of the concrete outer wall of the existing building, which was coated with a fluororesin, so as to have a dry film thickness of 2 to 5 μm, and dried.

[Example 3] To 100 parts of the surface treating agent 6 in Example 2, 100 parts of the solvent-soluble fluororesin composition solution adjusted to the formulation of Table 1 was added to prepare a surface treating agent 7. A part of the outer wall of the fluororesin-coated aluminum panel of the existing building was overcoated in the same manner as in Example 2 and dried.

[Example 4] Coronate HX (manufactured by Nippon Polyurethane) and Aerosil T in the solvent-soluble fluororesin composition solution used in the preparation of the surface treatment agent 7 of Example 3
Using the composition solution (solid content 2% by weight) excluding 600 (manufactured by Nippon Aerosil), the surface treatment agent 6 in Example 2 was used.
100 parts of this solution was added to 100 parts of this solution to produce a surface treatment agent 8, and a part of an outer wall made of a fluororesin-coated ALC (lightweight cellular concrete) was overcoated in the same manner as in Example 2 and dried.

"Comparative Examples 2, 3, and 4" In the outdoor articles of Examples 2, 3, and 4, the portions not surface-treated with the surface-treating agent were evaluated.

The results of Examples 2-4 and Comparative Examples 2-4 are shown in Table 2.
Shown in It is considered that rain streaks were not observed in Examples 2 to 4 due to the action of the hydroxyl group of the hydrolyzate of the compound having a hydrolyzable silyl group such as ethyl silicate 40, and the minus ΔL value became small. The ΔL value in Table 2 represents the change in lightness, and the larger the negative value, the more the rain streak stain is generated.

[0094]

[Table 1]

[0095]

[Table 2]

[0096]

By the treatment with the surface treating agent of the present invention,
It prevents the generation of streak-like stains that are likely to occur in a portion where rainwater gathers and flows under the window frame of a building.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 7/04 Z C09D 5/00 PPG PPT PPU PSD 183/04 PMS E04F 13/02 B 9127-2E (31) Priority claim number Japanese Patent Application No. 6-92205 (32) Priority date Hei 6 (1994) April 28 (33) Country of priority claim Japan (JP) (72) Inventor Bunji Uchino Kawasaki City, Kanagawa Prefecture 2-474 Tsukakoshi 3-chome, Sachi-ku, Asahi Glass Co., Ltd. Tamagawa Branch Office

Claims (12)

[Claims] 1. A silane compound (A) having a silanol group obtained by hydrolyzing a tetrafunctional hydrolyzable silane compound or a multimer thereof, or a medium containing the silane compound (A) and a synthetic resin film-forming component (C). It is dissolved or dispersed in (B), and the content ratio of the silane compound (A) is the medium (B).
The surface of the coating film of an outdoor article having a hydrophobic synthetic resin coating film is treated with a surface treatment agent in an amount of 0.01 to 100 parts by weight based on 100 parts by weight, and the silane compound is applied to the coating film surface. A method for treating an outdoor article surface, which comprises forming a thin film formed from (A) or the silane compound (A) and a synthetic resin film-forming component (C). 2. The method of claim 1, wherein the tetrafunctional hydrolyzable silane compound is tetraalkoxysilane. 3. The method according to claim 1, wherein the synthetic resin film-forming component (C) is a fluororesin. 4. The method according to claim 1, 2 or 3, wherein the surface treatment agent further comprises an acid catalyst or a buffer (D). 5. The method according to any one of claims 1 to 4, wherein the medium (B) is an aqueous medium, and the surface treatment agent further contains a surfactant (E). 6. The method according to claim 1, wherein the hydrophobic synthetic resin coating film is a fluororesin coating film. 7. A surface treatment agent containing the following silane compound (A) or the following silane compound (A) and a synthetic resin film-forming component (C) on the surface of an outdoor article having a hydrophobic synthetic resin coating film. An outdoor article having a thin film formed from, wherein the silane compound (A) is a silane compound (A) having a silanol group formed by hydrolyzing a tetrafunctional hydrolyzable silane compound or a multimer thereof. 8. The outdoor article according to claim 7, wherein the tetrafunctional hydrolyzable silane compound is tetraalkoxysilane. 9. The outdoor article according to claim 7, wherein the hydrophobic synthetic resin coating film is a fluororesin coating film. 10. The outdoor article according to claim 7, wherein the thin film has a thickness of 0.01 to 50 μm. 11. A thin film formed from a silane compound (A) is obtained by dissolving or dispersing a silane compound (A) or a silane compound (A) and a synthetic resin film forming component (C) in a medium (B). And a silane compound (A) content of 0.01 to 100 parts by weight relative to 100 parts by weight of the medium (B) is applied to the surface of the hydrophobic synthetic resin coating film and dried. The outdoor article according to claim 7, which is a formed thin film. 12. The outdoor article according to claim 7, wherein the synthetic resin film-forming component (C) is a fluororesin.