JPH11158648A - Surface treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart antifouling, dustproof, waterproof and moistureproof properties, rust preventiveness, etc., to the surface of a substrate and to maintain these characteristics even in a severe service environment by treating the surface of the substrate with a compd. contg. Si, Al or Ti. SOLUTION: The compd. used for surface treatment is represented by the formula Rn X(OR')m-n , wherein R is alkyl, alkenyl or phenyl, R' is alkyl, X is Si, Al or Ti, 0<=n<=3, m=3 in the case of Al and m=4 in the case of Si or Ti. An organoalkoxysilane or organosilanol obtd. by hydrolyzing it, e.g. monomethyltrimethoxysilane is suitable for use as the silicon compd. A trialkoxy-aluminum compd. or its hydrolyzate is suitable for use as the aluminum compd. An organoalkoxy-titanium or organotitanol obtd. by hydrolyzing it is suitable for use as the titanium compd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the treatment of the surface of a base material such as metal, glass, ceramics, paper, resin, etc., so that the surface of the base material is stainproof, dustproof, waterproof, moistureproof, rustproof, A surface treatment method that imparts surface properties such as lubricity, release properties, stain release properties, and water and oil repellency, and has excellent durability in these properties.

[0002]

2. Description of the Related Art Conventionally, metal surface treatment has been mainly used for rust prevention,
Chemical conversion treatment has been performed for the purpose of corrosion prevention. For example, a phosphoric acid film treatment is performed on a steel plate or a zinc surface, and an alumite film treatment is performed on an aluminum plate. Various pretreatments have been attempted for coating and the like. These coating treatments are mainly for the purpose of rust prevention and surface protection of steel plates and aluminum plates. In general, it is known that various coupling agents and metal oxides are effective for improving the adhesiveness of the surface of a metal or the like.
It is known to impart non-adhesiveness by heat treatment of a fluororesin or the like. However, a simple surface treatment technique has not been sufficiently established for improving the antifouling property, adhesion property, or coating property of the surface of, for example, stainless steel or glass. In addition, there is no known processing method that imparts surface characteristics with excellent durability to a generally poorly adherent substrate, not limited to metal, and can cure at room temperature with a thin film having excellent denseness.

[0003]

As described above, conventionally, not only metals such as stainless steel and aluminum, but also glass,
It has been impossible to form a durable thin film on the surface of a base material such as porcelain, paper, resin, etc., which usually has poor adhesiveness, and to cure the film by room temperature curing. In this regard, the present invention has been solved by a treatment based on a reaction that enhances the adhesion and by a clever combination of this undercoating and topcoat. Then, it is possible to impart surface properties such as antifouling property, dustproof property, waterproof property, moistureproof property, rustproof property, lubricity, mold release property, stain release property, water repellency and oil repellency to the substrate surface. We have found a surface treatment method that is excellent in the durability of these surface characteristics even in an environment. Moreover, it is a very thin, transparent and excellent dense film, and has the characteristic that it can be cured at room temperature.

[0004]

The object of the present invention can be attained by treating the surface of a substrate with a compound containing silicon, aluminum or titanium, alone or as a mixture of two or more. They are mainly alkoxy groups, or O
Compounds in which the H group is directly bonded to silicon, aluminum or titanium atoms are preferred. By these, hydrogen bond to the substrate surface,
Further, a film is formed by a condensation reaction. Further, the effect can be more remarkably achieved by performing an overcoating treatment on the base material with a silicone compound or a fluorine compound or a derivative thereof.

As the silicon compound, organoalkoxysilanes or organosilanols obtained by hydrolyzing them are generally suitable. The reaction can be accelerated by heating or catalysis. Acids, alkalis, organic amines and the like can be used as the catalyst. The organic amine catalyst is preferably a tertiary amine having a pKa of 8 or more, particularly preferably 9 or more. Organosilanols, of course, those obtained by other production methods can also be used. For example, when an organohalosilane is brought into contact with water, a hydrolysis reaction is caused to generate a silanol compound. Examples of the organoalkoxysilane include monomethyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, tetramethoxysilane, monoethyltriethoxysilane, diethyldiethoxysilane, tetraethoxysilane, methylethyldimethoxysilane, monophenyltrimethoxysilane, and the like. In addition, a silane coupling agent can also be used. These are converted to organosilanols by hydrolysis. As the organosilanol, R _n Si is generally used.
(OH) _4-n , wherein R is an alkyl group, an alkenyl group or a phenyl group, and n is 0-3. Examples include monomethylsilanol, dimethylsilanol, trimethylsilanol, silanol (tetrahydroxysilane), monoethylsilanol, diethylsilanol, triethylsilanol, monopropylsilanol, dipropylsilanol, tripropylsilanol, triisopropylsilanol, diphenylsilanediol, and the like. Can be. The organosilanol easily forms a hydrogen bond on the surface of the substrate by heating or a catalyst, and forms a strong film by a condensation reaction. The reaction proceeds even at room temperature.

In the case of an aluminum compound, for example, a trialkoxyaluminum compound and a hydrolysis product thereof, such as aluminum hydroxide (trihydroxyaluminum), form a film on the substrate surface in the same manner as in the case of a silicon compound. Other trialkoxy aluminum compounds include triisopropoxy aluminum,
Monosec-butoxydiisopropylaluminum, triethoxyaluminum and the like can be mentioned. Also, an aluminum-based coupling agent can be used.

[0007] The titanium compound is an organoalkoxytitanium, as in the case of the silicon compound, and an organotitanol obtained by hydrolyzing the same. Examples of the organoalkoxytitanium include monomethyltrimethoxytitanium, dimethyldimethoxytitanium and trimethylmonomethoxytitanium. Titanium, tetramethoxytitanium, tetraisopropoxytitanium, tetrapropoxytitanium, tetra-n-butoxytitanium, tetraethoxytitanium, diphenyldimethoxytitanium and the like, and other titanium coupling agents can also be mentioned. The organo titanols include R _n Ti
(OH) _4-n , wherein R is an alkyl group, an alkenyl group or a phenyl group, and n is 0 to 3
It is. For example, monomethyltrihydroxytitanium, dimethyldihydroxytitanium, trimethylhydroxytitanium, tetrahydroxytitanium, monoethyltrihydroxytitanium, monopropyltrihydroxytitanium, diphenyltitaniumdiol and the like can be mentioned.

The OH groups of these compounds are converted to OH groups on the substrate surface.
The formation of a film by hydrogen bonding with the group is considered, and the more OH groups generated by hydrolysis, the stronger the film formation. That is, RSi (OH) ₃ , Si (OH) ₄ , Al
(OH) ₃ , RTi (OH) ₃ , or Ti (OH) ₄
Is hydrogen-bonded on the surface of the base material and undergoes a more rapid condensation reaction or cross-linking reaction, thereby forming a stronger film and exhibiting a strong bonding property with the overcoating agent.

[0009] The concentration of these compounds is preferably 0.1 to 20% by weight, and as the solvent, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, etc., and paraffinic hydrocarbons and aromatic hydrocarbons are used. General organic solvents such as n-hexane, toluene, chlorobenzene and the like can be used, and a mixture thereof may be used. Furthermore, when these compounds are used as a mixture of two or more, any mixing ratio can be selected. The coating can be obtained by applying, spraying or dipping the liquid adjusted to a predetermined concentration with a brush or the like, and the coating is formed by air drying or heat treatment. One of the features is that the film can be cured at room temperature as described above, but the heat treatment has an effect of forming a film more quickly.

Further, by adding an organic amine catalyst or the like, the reaction can be accelerated and a film can be easily formed. The organic amine catalyst is a tertiary amine and has an acid dissociation constant pKa.
Of 8 or more is effective, and 9 or more is more preferable.

The target substrate is a metal such as stainless steel, an aluminum plate, an iron plate, PET, polypropylene, polyethylene,
Resins such as polystyrene, polyvinyl chloride, bovar, nylon, and ABS, films, fibers (natural and synthetic), paper, glass, and ceramics can be coated. The present invention also provides a silicone compound,
By applying a top coat treatment of a fluorine compound or a derivative thereof, the characteristics of the base treatment are further enhanced and utilized,
Furthermore, various functions of the overcoating process itself can be provided. Of course, the adhesion between the undercoat layer and the overcoat layer is excellent, and there is no problem in durability under severe use conditions. In the case of performing the overcoating treatment of the silicone compound, a two- or more-layer coating can be carried out using a silane coupling agent, another silane compound, polyorganosiloxane, reactive silicone, or the like. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxy Silane and the like can be mentioned.

In the same manner as the silicone compound, the fluorine compound can be coated with the fluorine compound on the undercoating. As a fluorine compound or a derivative thereof, in addition to omega hydroperfluoroalcohol of the general formula H (CF ₂ CF ₂ ) _n CH ₂ OH (where n = 1 to 6), perfluoroalcohol, perfluoro (meth) acrylate, And their oligomers,
Other examples include perfluorophosphate esters and perfluoroalkylsilanes. By adding a silicon compound to the fluorine compound or its derivative, the effect can be further enhanced as a hybrid. As the silicone compound, good results can be obtained by using a curable or modified silicone in addition to the usual silicone types such as oil and varnish. For example, a modified silicone having a terminal or a side chain such as amino type, amino polyether, epoxy, epoxy polyether, carboxyl, carbinol, etc. can be used.

Practical examples of the surface treatment according to the present invention include antifouling treatment of stainless steel gas stoves, gas stove pans, pots and PVC wallpaper, and stainless steel plate or aluminum sash. Can be. For example, when cutting an alumite-processed aluminum plate, applying this to the cut surface is also effective in preventing corrosion and the like. In addition, it can be applied to the joints of bathroom tiles and the pipes of tap water to enhance the waterproof, rust-proof and anti-fouling effects. In addition, water resistance can be imparted to the hydrophilic poval film.

Next, an embodiment will be described in more detail.

Example 1 3 g of ethyl orthosilicate (tetraethoxysilane) was placed in a 100 cc beaker, and 3 g of ethyl alcohol and 4.1 g of 2% hydrochloric acid were added.
Is added slowly to hydrolyze the ethyl orthosilicate.
At this time, to accelerate the reaction, 1 g of a 10% organic amino catalyst is added with stirring. As such a hydrolysis product, tetrahydroxysilane or a derivative thereof is obtained, which is then dissolved in ethyl alcohol at a predetermined concentration of 3%.
The diluted solution is referred to as a base treating agent A-1 solution. This A-
Using one liquid, an untreated stainless steel plate (thickness: 0.5 mm) on which the surface of the base material has not been processed was cut into four pieces of 50 × 100 mm, and the surface was uniformly applied with a brush. . Two of the four coated sheets were dried at room temperature for about 1 hour, and the remaining two sheets were dried at 160 ° C. for 30 minutes in a constant temperature electric furnace to cure the coating films. On the other hand, as an overcoating agent, 10 g of a perfluoroalkoxysilane compound manufactured by Yamanan Gosei Co., Ltd. was taken, hydrolyzed by adding an organic amine-based catalyst with a theoretical reaction amount of hydrochloric acid in the same manner as above, and the The product is referred to as Overcoat B-1 solution. This B
Solution-1 is diluted to a predetermined concentration of 10% with an alcohol mixture mainly composed of an ethanol solution. Further, 2.5 g of a room temperature-curable reactive silicone manufactured by Shin-Etsu Chemical Co., Ltd. was added to improve the compatibility with the base treatment. Then, after applying the above-mentioned A-1 solution, drying at room temperature and 160 ° C.
And dried for 30 minutes in the first layer to cure each one,
B-1 solution is applied as a second layer, and the temperature is 160 ° C. in a constant temperature electric furnace.
For 30 minutes to obtain test samples. About 2 g of banana pulp was rubbed on each of the four test sample plates, and carbonized at 160 ° C. for 30 minutes. After cooling to room temperature after carbonization, the portion adhering when cooled to room temperature, that is, the flesh of the carbonized banana was lightly extruded with the tip of a spatula, and its peeling properties were compared. The evaluation was always scored simultaneously by 4 to 5 persons, and the average value was obtained except for the maximum and minimum results. Table 1 shows the results.

Comparative Example An untreated stainless steel plate (thickness: 0.5 mm) was cut into a size of 50 × 100 mm, and its surface was not subjected to any treatment. Rubbed in a constant temperature electric furnace at 160 ° C.
Heated for 0 minutes. When cooled to room temperature after firing, the carbonized and attached banana flesh was lightly extruded with a tip of a spatula to examine its peelability. The evaluation was always scored simultaneously by 4 to 5 people, and the average value was taken except for the maximum and minimum results. Table 1 shows the results.

Example 2 In addition to the tetrahydroxysilane as the undercoating agent in Example 1, a mixture of tetrahydroxytitanium and the former was used, and the peelability of banana flesh charcoal was measured in the same manner as in Example 1. Tested. The tetrahydroxytitanium used was organic titanate TBT (tetra n-butoxytitanium) and TPT (tetraisopropoxytitanium) manufactured by Nippon Soda Co., Ltd., and isopropyl alcohol was used as a solvent.
The results are shown in Table 2 in comparison with untreated.

Example 3 In order to evaluate the durability of the peeling property, the test piece was immersed in a hot water bath at about 40 ° C. after the peeling test on the stainless steel plate in Examples 1 and 2 was completed. The attached carbide was gently rubbed and removed, and the easiness of removing the attached matter at that time was evaluated organoleptically by Δ ×. Then, after washing and drying these, about 2 g of banana pulp again as described above
Was rubbed and subjected to a heat treatment at 160 ° C. for 30 minutes. This was repeated 10 times, and the same evaluation was shown in Table 3 every time.

Next, a film was formed on the surface of the base material by hydrolysis of the organoalkoxytitanium, and a paint was applied to the surface.

Example 4 An organic titanate TBT (tetra-n-butoxytitanium) manufactured by Nippon Soda Co., Ltd. was diluted to 3% with isopropyl alcohol, and then diluted with a brush to a thickness of 40 mm square having a thickness of 0.1 mm. A 3 mm untreated stainless steel plate, a 0.5 mm thick aluminum plate, and a 1.3 mm glass plate were uniformly applied to the respective surfaces, and then heated at 160 ° C. for 30 minutes to cure the coating film and perform a base treatment. Next, a spray “Nippe Home Paint” (alkyd resin) for marking manufactured by Nippon Paint Co., Ltd. was applied to each of the test pieces subjected to the above-mentioned base treatment, and air-dried. Using a sharp knife on this coating film, 11 parallel and parallel grooves reaching the substrate were cut at 1 mm intervals vertically and horizontally to form 100 squares (10 × 10). Nichiban Scotch tape (18 mm width) was pressed on it and immediately peeled off.
Of the 100 Goban eyes, there is no peeling or partial loss,
The adhesiveness was evaluated based on the completely remaining number (Gobain test). At the same time, for comparison, the organic titanate TBT was used.
Was applied with a paint similar to that described above, and subjected to a goban test. The results are shown in Table 4.

[0021]

Claims (7)

[Claims] 1. A compound of the general formula R _n X (OR ′) _mn (wherein R is an alkyl, alkenyl or phenyl group, R ′
Represents an alkyl group, X represents silicon, aluminum or titanium, n = 0 to 3, aluminum is m = 3, silicon or titanium is m = 4) or a compound represented by the hydrolysis product thereof. A surface treatment method characterized by treating a kind of a substrate surface. 2. The surface treatment method according to claim 1, wherein X is silicon. 3. A surface treatment method according to claim 1, wherein X is aluminum. 4. A surface treatment method according to claim 1, wherein X is titanium. 5. A surface treatment method comprising subjecting a surface of a base material to a base treatment by any one of the methods according to claim 1 and performing an overcoat treatment thereon. 6. A surface treatment method according to claim 5, wherein a silicone compound or a derivative thereof is used as the overcoating treatment. 7. A surface treatment method according to claim 5, wherein a fluorine compound or a derivative thereof is used as the overcoating treatment.