JPH0788491B2 - Paint containing titanium oxide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a titanium oxide-based coating material having excellent weather resistance.

[Outline of Invention]

The present invention relates to a coating paint containing titanium oxide, which is useful for increasing abrasion resistance, ultraviolet shielding, antireflection, increase in reflection, and chemical resistance, in which a specific metal compound containing an organic group is contained in a vehicle. Suppresses the photoreaction caused by titanium oxide in the obtained coating film, and improves the weather resistance of the coating film.
It has improved light resistance.

[Conventional technology]

Titanium oxide has an excellent ability to absorb ultraviolet rays, and a coating using fine particles has a great potential as an infrared reflective film.
Various studies have been made.

In addition, it is practically used as a mixture of white pigments and ultraviolet shielding paint.

Further, titanium oxide is chemically active although it is active with respect to light. Applying this property to a transparent coating film is also under study. Examples of this include, for example, U.S. Pat.
No. 118 is mentioned.

In these examples, in order to suppress the deterioration of light resistance due to titanium oxide, the surface of titanium oxide particles is coated with optically stable silicon dioxide, or a silicon-based coupling agent and colloidal silica are used as a binder to improve the characteristics. I'm thinking.

[Problems to be solved by the invention]

However, among these conventional techniques, the method of coating the surface of titanium oxide particles with silicon dioxide is effective for titanium oxide particles having a diameter of several hundreds of microns or more,
In the case of the fine particles described in the present invention, there is a problem that the surface area is large and the particle surface cannot be sufficiently covered.

Further, in the latter example, there is a problem that part of the silicon-based coupling agent deteriorates, and when the base material is a synthetic resin, the interface with the base material is deteriorated by light and coating film peeling occurs. .

Therefore, the present invention solves such a problem,
An object of the invention is to provide a coating composition having abrasion resistance, ultraviolet ray shielding property, chemical resistance, and excellent weather resistance or light resistance, and a transparent coating film obtained from the coating composition.

[Means for solving problems]

The coating material containing titanium oxide of the present invention is characterized in that the binder vehicle containing titanium oxide fine particles contains at least one or more of the following components (A) or (B).

(A) Coordination compound of metal acetylacetone or metal acetoacetate selected from Co, Pd, Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi, Mo (B) Co, Pd , Metal aracholate compound selected from Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi and Mo will be described in more detail.

The titanium oxide fine particles used here have a particle size of 1 to
The one of 100 mm is suitable. If the particle size is 1 millimicron or less, sufficient abrasion resistance and ultraviolet ray shielding effect cannot be obtained, and if the particle size is 100 millimicron or more, the obtained coating film becomes cloudy and the transparency decreases and at the same time the light resistance is reduced. Sex decreases.

Next, as the organic compound having a metal species used in the present invention,
Metal acetylacetone selected from Co, Pd, Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi, Mo, methyl acetoacetate acetate, chelate compound of ethyl acetoacetate, propyl acetoacetate, or
Co, Pd, Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi, Mo selected from acetate, propionate, butyrate, lactate,
Examples thereof include alcoholates of ethoxide and butoxide.
Among these, compounds having ligands of acetylacetonate and acetoacetate are stable in water and temperature,
Particularly preferred.

The metal compound can be added in a weight ratio of titanium atom to metal atom of 100 ppm to 10%. Ten
If it is 0 ppm or less, the effect cannot be obtained, and if it is 10% or more, it becomes difficult to prepare a coating solution, which is not preferable.

Next, examples of the material used as the binder vehicle include a silane coupling agent, a silicon oxide sol, a synthetic polymer, a natural polymer, a modified natural polymer or a reactive monomer. Further, it is composed of one or more of a thickener, a flow control agent, a leveling agent, a solvent, a dye and the like.

Here, the silane compound has, for example, a general formula There are silane coupling agents represented by and tetraalkoxysilanes. These hydrolyzates and partial condensates have the same properties.

Here, R ¹ is an alkyl group, an alkenyl group, a phenyl group,
A halogen group or the like, R ² is an organic group including an epoxy group, an amino group, an amide group, a mercapto group, a methacryloyloxy group, a cyano group, a group having a nuclear halogenated aromatic ring, X is a halogen group, It shows a hydrolyzable group such as an alkoxyl group, an alkenoxy group, an alkoxyalkoxyl group, and an acyloxy group. Also, a and b are 0, 1 or 2 respectively.
And a + b is 1 to 3. Examples of these compounds include tetrafunctional silanes such as tetramethoxysilane, methyltrimethoxysilane, γ-chloropropyltrimethoxysilane, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, β- (3,4 −
Epoxycyclohexyl) ethyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ
-Aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-cyanopropyltrimethoxysilane, γ-morpholinopropyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane and other trifunctional silanes, A bifunctional silane in which a part of the functional silane is replaced with a methyl group, an ethyl group, or a vinyl group can be used.

Examples of the organic binder component include polymers such as carboxyalkylated celluloses, terpene resins, glucose derivatives, polyamino acids, chitins, chitosans, and natural polymers such as starches.
Synthetic polymers with polar groups such as polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, polyvinylamine, polyurethane, polyvinylpyrrolidone, polyvinylpyridine, polyvinylimidazole, polystyrene, bisphenol A, Examples include aromatic polymers such as polycarbonate, functional resins such as polysulfones, and modified fluorine-based polymers.

Examples of reactive monomers or oligomers include photocurable polyfunctional acrylates, epoxy compounds such as ethylene glycol diglycidyl ether, ring-opening polymerizable monomers such as lactones, and reactive monomers such as isocyanates. You can

The coating liquid is preferably a solution containing 1 to 20% by weight of a solid component diluted with a solvent such as alcohols, esters, ketones, cellosolves, formamides, water, and Freon, but not always limited. It is not something that will be done.

Next, as a method for obtaining a coating film, various coating methods can be used. Also, drying and curing is, for example, 40-200 ℃
A heating method of 10 minutes to 10 hours is suitable, but in addition to this, processes such as infrared ray, ultraviolet ray, γ-ray and electron beam irradiation can also be used if necessary.

[Action]

The coating film containing titanium oxide obtained in this manner will be described below with respect to the function of improving light resistance and ensuring transparency.

That is, regarding the light resistance of (i), although the detailed principle is unknown, some photocatalytic effects of titanium oxide have been reported (for example, GN Schrauzer and TDGuth, J. Am. Chem, So.
c., 99 , 7189 (1977)). The present invention considers that titanium oxide fine particles also have an active site for photocatalytic activity, and has added various metal species, and found a metal that is particularly effective. Therefore, as a mechanism, these metals or metal chelate compounds are present in the coating film near the photoactive point of titanium oxide or with a weak bond, and the photocatalytic ability, that is, the conversion of light energy into chemical energy is performed. You can guess that it can prevent the conversion. In other words, the photocatalytic ability of titanium oxide converts light energy into chemical energy to create chemically active species, which cuts or modifies the chemical bonds of the vehicle of the coating film containing titanium oxide. I think it was. It is considered that the present invention suppresses the redox ability by suppressing the conversion process of light energy of titanium oxide into chemical energy or by converting the converted light energy into heat energy. That is, the light resistance of the coating film is improved by such an action of the added metal species.

(B) To ensure transparency, use a titanium oxide particle type of 100
By setting the particle size to be less than or equal to millimicrons, it was possible to suppress irregular reflection on the particle surface and increase transparency. Correlation has been found in colloid chemistry between the wavelength of light that seeks to increase transmittance and particle size (e.g., H. Weller et.al., Chem. Phys.
Letters, 124 , 557 (1986). The present invention was found by investigating a level where there is no problem in transparency in the wavelength range of visible light when titanium oxide and metal species are evenly dispersed in the binder vehicle, and in the cited example, particles of 10 mm or less are used. Although the diameter is required, it has been found that the reflection at the interface between the particles and the polymer is within an allowable range by making the titanium oxide particles have a predetermined particle diameter and uniformly dispersing the particles in the binder.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but these do not limit the present invention.

In the examples, “part” means “part by weight”.

Example 1 (1) Preparation of Paint Containing Titanium Oxide Titanium dioxide aqueous sol (particle size: 10 millimicrons, solid content: 10% by weight, aqueous dispersion colloid) was placed in a glass flask having a stirring device with a magnetic stirrer. Add 10 parts of water, mix well, and mix with 15 parts of water, followed by ethyl cellosolve.
15 parts were added to obtain a titanium oxide colloidal solution.

Cobalt ^II acetylacetonate dihydrate 0.15
A solution prepared by dissolving 2 parts of acetylacetone in 8 parts of ethyl cellosolve was slowly added to obtain a colloidal dispersion containing cobalt atoms. In this dispersion, the cobalt content with respect to titanium atoms is 5% by weight.

The liquid containing the binder vehicle to be mixed next was prepared as follows. That is, in a reaction flask, 1.5 parts of γ-glycidoxypropyltrimethoxysilane, 20 parts of ethyl cellosolve, and 1.0 part of 0.1N hydrochloric acid water were stirred and mixed to hydrolyze the silane compound to obtain a binder solution.

This binder solution is added to the titanium oxide colloidal solution,
After slowly adding with stirring, a small amount of a silicon-based surfactant was added to obtain a coating material for coating.

(2) Forming a coating film by coating and curing the paint
A polycarbonate panel plate treated for seconds was applied by a spin coating method and then dried and cured at 100 ° C. for 3 hours to obtain a uniform coating film.

(3) Evaluation Test of Coating Film and Results The composite thus obtained was evaluated by the following procedure.

Abrasion resistance: The surface of a test piece having a size of 1 cm x 3 cm was visually inspected with a steel wool (# 0000) to apply a load of 100 g per 1 cm ^{2 and} rub it for 10 reciprocations. The evaluation rank criteria are as follows.

A: No scratches in the area of 1 cm x 3 cm.

B: 1 to 10 scratches are made within the above range.

C: 10 to 100 scratches are made within the above range.

D: There are countless scratches, but there is still a smooth surface.

E: No smooth surface remains due to scratches on the surface.

Hot water resistance: The lens was immersed in boiling pure water for 1 hour, and then tested for abrasion resistance in the same manner as above.

Chemical resistance: The appearance of the test piece after immersion in a 4% aqueous sodium hydroxide solution for 1 hour and the appearance after immersion in 10% hydrochloric acid for 10 hours were evaluated.

Light resistance (weather resistance): A xenon lamp fade meter (Suga Tester FAL-25AX type) was used to evaluate the change in the coating film after 100 hours of light exposure.

Adhesion: In the so-called cross-cut tape test, 11 parallel cuts were made at a 1 mm interval perpendicular to each other with a knife, and 1 mm
Make 100 squares of ³ . Next, an adhesive tape (trade name "Cellotape") was strongly adhered and rapidly peeled in the direction of 90 °, and the remaining squares were used as numerator and the denominator was taken as the total square to be used as an index of adhesion.

As a result of conducting a test based on the above evaluation method, this example shows that abrasion resistance: B, hot water resistance: no abnormality, chemical resistance: no abnormality, light resistance: hardness slightly decreases from B to C, appearance, and
In the test, there was no abnormality. Adhesion: 100/100 was good. Further, the coating film was transparent and was good without turbidity even after the light resistance test, no yellowing and no decrease in adhesion were observed. In particular, the polycarbonate, which is the base material, slightly yellowed as it was, but in the test piece of this example, such yellowing was hardly seen, so it can be assumed that it has excellent ultraviolet shielding properties. .

This composite was dyeable with a commercially available disperse dye and was useful as a decorative panel.

Examples 2 and 3 In Example 1, a coating film was formed in the same manner as in Example 1 except that the substrate was changed to an aluminum plate and a polydiethylene glycol bisallyl carbonate lens, and a composite having a good appearance was obtained. . The light resistance of this composite was also good.

Examples 4-12 and Comparative Examples 1-7 In Example 1, cobalt ^II acetylacetonate 2
Instead of 0.15 parts of the hydrate, the metal compounds shown in Table 1 were used, and the amount used was set such that each metal atom accounted for 5% by weight of titanium atom in the coating composition. The coating material was adjusted and the coating film was formed in the same manner as in Example 1.
The composite thus obtained was evaluated according to the procedure of Example 1, and the test results obtained are shown in Table 2.

[Advantages of the Invention] The present invention provides a catalyst poison for the photocatalytic activity of titanium oxide by containing a coordination compound or an organic group-containing compound of a specific metal ion such as copper, vanadium, or lead in a coating material containing titanium oxide. As a result,
The effect that the light resistance of the coating film can be improved was obtained. Applying this effect, when applying titanium oxide to various paint additives to improve optical characteristics, durability,
Helps increase lightfastness. These paints, as a protective coat, improve wear resistance, chemical resistance, and water resistance,
In addition, it is useful for preventing stains and adding value for improving aesthetics. In particular, taking advantage of this characteristic of high refractive index, the antireflection film obtained by combining it with a low refractive index thin film can be applied to plastic films, plastic panels, plastic optical materials such as plastic lenses, and glass panels. It is possible. Other,
There are applications such as disks, panels, structural members, and optical parts.

Claims (2)

[Claims] 1. A coating material containing titanium oxide, characterized in that a binder vehicle containing fine particles of titanium oxide contains at least one or more of the following components (A) or (B). (A) Coordination compound of metal acetylacetone or metal acetoacetate selected from Co, Pd, Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi, Mo (B) Co, Pd , Alcolate compounds selected from Ag, Cr, Pb, Cu, V, Pt, W, Hg, La, Bi and Mo 2. The coating material containing titanium oxide according to claim 1, wherein the titanium oxide fine particles have a particle diameter of 1 to 100 millimicrons.