JPH0450280A - Fade-inhibiting structural body and paint therefor - Google Patents

Abstract

PURPOSE:To obtain the subject structural body protecting a base material mainly from ultraviolet rays by forming a transparent film in which fine particles of ultraviolet rays-shielding metal oxide on the surface of the base material containing fluorescent or phosphorescent dye or pigment. CONSTITUTION:A transparent film having <=10 (preferably <=1) haze in which fine particles of ultraviolet rays-shielding metal oxide composed of zinc oxide preferably having <=0.1mum (especially 90% of the particles have 0.005-0.05mum) particle size is dispersed in an amount of 5-90wt.% (preferably 40-80wt.%) in a solid component of the paint is formed on the surface of a base material containing fluorescent or phosphorescent dye or pigment.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention involves forming a transparent ultraviolet-shielding coating film on the surface of a substrate containing fluorescent or phosphorescent dyes or pigments, thereby protecting the substrate from mainly ultraviolet rays. The present invention relates to an anti-fading composition that protects the composition from fading and its coating.

I Problems to be Solved by the Prior Art and the Invention 1 Fluorescent and phosphorescent dyes and pigments are easily decomposed by the ultraviolet rays contained in sunlight, and for this reason they can only be used indoors. is limited. If used outdoors, the color will fade in a few days, making it impractical. Colored pigments and dyes generally have a tendency to fade due to ultraviolet rays, and among these, fluorescent and phosphorescent dyes and pigments have a particularly strong tendency to fade. For this reason, if fluorescent and phosphorescent dyes and pigments were made UV resistant and could be used outdoors,
Its product value increases significantly. Thus, there has been a long-awaited development of a means to simply and effectively impart UV resistance.

Conventionally, when fluorescent or phosphorescent dyes or pigments are used, a method to prevent fading while maintaining the color tone is to use transparent dyes containing organic ultraviolet absorbers such as benzophenone, salicylate, and substituted acrylonitrile. There is a known method of creating a UV-based paint and applying it directly to the object to prevent fading in a thick film, or directly mixing and adding these organic ultraviolet absorbers into a base material containing dyes and pigments. ing.

Now, regarding the method of directly mixing and adding an organic UV-shielding substance into a base material containing fluorescent or phosphorescent dyes or pigments, the above-mentioned organic UV absorbers themselves are easily degraded by UV rays. Because the structure changes, or it bleeds out from the base material and is easily lost, the concentration of the organic UV absorber in the base material decreases, and the protective function from UV rays decreases.
It will decline over time. Furthermore, since most of the absorption edges are on the low wavelength side of about 350 nm or less, the protection effect from ultraviolet rays is weak. Furthermore, organic ultraviolet absorbers generally have limited solubility in various substrates and solvents, and the amount added is limited to a small amount. For this reason, when directly blended with fluorescent or phosphorescent dyes or pigments, the concentration of organic ultraviolet absorbers is kept low, and as a result, ultraviolet rays incident from the base material reach quite deep inside, and the ultraviolet rays from the side closer to the surface This causes fading of fluorescent and phosphorescent dyes and pigments and deterioration of the substrate structure.

Next, when an organic UV absorber is blended into a transparent paint and applied to a substrate containing fluorescent or phosphorescent dyes or pigments, the solubility of the organic UV absorber in the paint binder is Therefore, in order to obtain the necessary and sufficient shielding ability, it is necessary to apply a thick coating with a dry film thickness of several tens of micrometers or more. For this reason, the coating method is limited to screen printing and spray coating methods that allow thick coating, and thin film high-speed printing techniques such as gravure printing and offset printing cannot be used, which poses major problems in terms of workability, cost, range of use, etc. .

Therefore, the technical problem of the present invention is to have a UV shielding ability over a wide range up to just before the visible light range, to have good visible light transmittance, excellent weather resistance, and to have sufficient UV shielding ability with a thin film. This makes it possible to use coating methods such as gravure printing and offset printing, and to produce an anti-fading composition that can be applied in large quantities at low cost, as well as a fluorescent or phosphorescent composition consisting of a transparent liquid in which fine metal oxide particles are dispersed. Our objective is to provide anti-fading paints for light dyes and pigments.

Therefore, the present invention creates a paint containing zinc oxide in order to impart such UV resistance, uses this to block UV rays, and converts a shielding film that transmits visible light into a film that is fluorescent and phosphorescent. It was discovered that if it is prepared on a substrate containing dyes and pigments, fading can be prevented without impairing the color tone of the substrate, and it can be used outdoors. Based on this point of view, the present invention has been made. It is something.

Therefore, the present invention involves forming an ultraviolet shielding film on a base material containing a fluorescent or phosphorescent dye or pigment, which has an ultraviolet blocking ability and has good transparency against visible light and other light rays. an anti-fading composition that protects the material mainly from ultraviolet rays, and a fluorescent or phosphorescent dye consisting of a transparent liquid in which fine metal oxide particles are dispersed;
The purpose of the present invention is to provide an anti-fading paint for pigments.

[Means for Solving the Problems] The present invention provides an anti-fading structure in which a transparent film in which UV-shielding metal oxide fine particles are dispersed is formed on the surface of a base material containing fluorescent or phosphorescent dyes or pigments. This is an anti-fading coating for fluorescent or phosphorescent dyes and pigments, consisting of a transparent liquid in which fine particles of metal oxides and metal oxides are dispersed. The metal oxide is preferably zinc oxide.

Further, the particle size of the zinc oxide is preferably 0.1 μm or less. Moreover, a coating material in which the content of zinc oxide is 5 to 90% by weight based on the solid content of the coating material is suitable. The transparent film preferably has a haze of 10 or less.

The present inventors focused on zinc oxide as an inorganic material that effectively blocks ultraviolet rays, and after preparing it into fine particles with a particle size of 0.1 μm or less, they made it into a binder containing 5 to 90% by weight of the solid content of the paint. On the other hand, a fluorescent or phosphorescent dye consisting of a transparent liquid in which fine particles of metal oxide are dispersed and an anti-fading composition that blocks ultraviolet rays up to near visible light and transmits visible light well by uniformly dispersing them. It was discovered that an anti-fading paint for pigments can be produced.

However, if the particle size of the zinc oxide used is 0.1 μm or more, the surface area per unit weight will be small, resulting in low ultraviolet shielding ability, and high light scattering in the visible light range will result in high haze. However, the desired anti-fading composition and the paint cannot be obtained.

That is, the fine particles of zinc oxide used in the present invention have a particle size of 0.
．． 1 μm or less, but preferably 90% of it is 0.0
Ultrafine particles within the particle size range of 0.05 to 0.05 μm are preferred.

Furthermore, if the amount of zinc oxide ultrafine particles added is less than 5% by weight based on the solid content of the paint, the UV shielding ability will be insufficient, and if it is more than 90% by weight, the proportion of the binder will be too small and the coating will have a sufficient degree of Since a film cannot be formed, the amount of zinc oxide ultrafine particles added must be 5 to 90% by weight based on the solid content of the paint. Furthermore, it is preferably 40 to 80% by weight.

Further, the haze of the transparent film formed from the anti-fading structure must be 10 or less so that the underlying object can be clearly seen. Preferably, it is 1 or less. There is no limit to the thickness of the transparent film, but from the viewpoint of workability, it is preferably 20 μm or less, but 1 to 5 μm, which can be used by gravure printing or offset printing, is preferable.
A film thickness of m is more suitable.

As a result, the coating film formed by applying the anti-fading transparent layer in which ultrafine zinc oxide particles are uniformly dispersed in a binder blocks a wide range of ultraviolet rays, while exhibiting high transmittance over the entire wavelength range of visible light. It has excellent transparency.

Zinc oxide fine particles having such properties are, for example,
It can be produced by the method described in the specification of patent application No. 130422 of 1999.

The zinc oxide powder having a particle size of 0.1 μm or less used in the present invention can be produced by a vapor phase evaporation-precipitation method, heat treatment of fine particles of zinc oxide of 20 Å or less, or the like.

The binder used in the paint of the present invention is not easily deteriorated by ultraviolet rays when used as a paint, has excellent weather resistance, and can form a film with high transparency, while at the same time providing excellent protection against the coated object. It must have good adhesion.

The above-mentioned properties may be imparted to such a binder by adding a stabilizer for preventing aging or the like.

As for the type of binder having the above properties, both ordinary organic binders and inorganic binders can be used. For example, polyester resin type, vinyl resin type, acrylic resin type, fluororesin type, silicone resin type, silicic acid type, etc. Alkali silicates such as soda, inorganic colloids such as silica sol and alumina sol, metal alkoxides such as tetraethoxysilane, phosphates such as aluminum phosphate, metal salts such as tin acetate, metal soaps, and organic metal compounds. One example is the system. Alternatively, two or more of the above-mentioned materials may be mixed or reacted to be used as a binder.

In addition, these binders include one or two selected from aromatic hydrocarbons, alcohols, esters, ketones, ethers, saturated hydrocarbons, chlorinated carbons, fluorocarbons, and water. It is used by being dissolved or dispersed in more than one type of solvent.

Furthermore, the fine particles of zinc oxide need to be uniformly dispersed in the binder, and for this purpose, for example, a ball mill, attritor, sand glider, triple roll, high speed impeller mill, jet mill, kneader, paint seeker, homogenizer, etc. An ultrasonic disperser or the like is used alone or in combination.

In addition, zinc oxide fine particles can be used in organic acid-based, coupling agent-based,
It is also preferable to use one or more selected from surfactants, metal soaps, metal salts, alkali silicates, phosphates, metal alkoxides, etc. to further promote dispersibility.

Next, the method for forming the above-mentioned fading preventing structure will be explained. This fading preventing structure can be formed by spray coating, dip coating, brush coating, spin cording, gravure printing, offset printing, or spraying on the object to be prevented from fading. A transparent film can be formed using a doctor blade, a bar coater, letterpress printing, screen printing, pad printing, planographic printing, flexo printing, etc.

Zinc oxide is used as the paint for forming the anti-fading transparent coating used in the present invention, because it has fluidity and the amount of binder needs to fill in the spaces between the ZnO particles to provide film strength. It is preferably 90% by weight or less in the solid content. Otherwise, the coating becomes extremely brittle. Furthermore, if the zinc oxide content is 5% by weight or less, the proportion of light that does not pass through the zinc oxide increases, which reduces the ultraviolet absorption efficiency, which is not preferable. The coating film produced using the coating film-forming material of the present invention has excellent ultraviolet blocking properties, and has excellent translucency, sanitary properties, weather resistance, and the like.

Next, the antifading composition of the base material containing fluorescent or phosphorescent dyes and pigments according to the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

[Preparation example 1 for anti-fading film] 30 parts by weight of acrylic varnish with non-volatile content of 50%, particle size of 0,
35 parts by weight of zinc oxide of 1 μm or less (average particle size 0.01 μm) and 60 parts by weight of ethyl acetate were mixed in a ball mill.
The mixture was stirred and dispersed for 0 hours to prepare an anti-fading transparent paint.

[Example 2 of material for anti-fading film] Solvent-soluble fluororesin varnish 20 with non-volatile content of 50% by weight
1 part by weight, 20 parts by weight of the same zinc oxide as anti-fading coating example 1,
30 parts by weight of butyl acetate was blended and stirred and dispersed in a ball mill for 20 hours to prepare an anti-fading transparent paint.

[Sakamo Danyu] 36 parts by weight of acrylic varnish with 50% non-volatile content, 2 parts by weight of 2-(2°-hydroxy-5-methylphenyl)benzotriazole, an organic ultraviolet absorber (this is equivalent to the weight of the dry coating). (equivalent to 10 parts by weight) and 80 parts by weight of toluene were blended and stirred and dispersed in an attritor for 4 hours to obtain a paint.

The amount of the organic ultraviolet absorber added in Comparative Example 1 is the maximum amount that will not cause whitening due to bleed-out in a shorter time than the binder when it is formed into a dry coating. In terms of the amount, a bleed-out phenomenon is observed, and there is no point in increasing the amount added.

[Danrijakoretsu-4 Coat using the same compounding ratio and operation as in Example 1 of the anti-fading paint,
A paint was prepared using zinc oxide (average particle size: 0.3 μm).

100 parts by weight of 50% non-volatile acrylic varnish, 10 parts by weight of fluorescent pigment (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.), 2-(2'-hydroxy-5-methyl organic ultraviolet absorber) A fluorescent pigment-containing paint was prepared by blending 5 parts by weight of phenylbenzotriazole and 200 parts by weight of toluene and stirring and dispersing the mixture in an attritor for 4 hours. Here, as the fluorescent pigments, yellow o-(FR-300C), orange (
FR-40) and Lyhood FR-30) were each used alone.

The amount of the organic ultraviolet absorber used here is the maximum amount that will not bleed out from the binder after coating and drying, and there is no point in increasing the amount of the organic ultraviolet absorber any further.

[Coating test] The paint prepared in Example 1 of the anti-fading paint was applied to a transparent polyethylene terephthalate (PET) film (12 μm thick).
A sample was prepared by coating the film with a dry film thickness of 1 μm using gravure printing.

Next, a transparent polyethylene terephthalate (PET) film (12
A dry film thickness of 4 μm was coated on a surface (μm thick) by gravure printing to prepare a sample.

Next, the paints prepared in Comparative Examples 1 and 2 were applied to a transparent polyethylene terephthalate (PET) film (thickness 12 μm).
A barcode was applied on top to a dry film thickness of 3 μm to serve as a comparison sample.

Among the above samples, paint example 1 for anti-fading coating and comparative example 1
．． The spectral transmission characteristics of the paint obtained in step 2 are shown in FIG. In FIG. 1, the spectral transmission curve of the paint Example 1 for anti-fading coating shows that it transmits light well in the visible range up to 400 nm, while completely blocking ultraviolet rays of 385 nm or less.

On the other hand, the spectral transmission curve of the paint of Comparative Example 1 shows that the transparency is sufficient, but the UV shielding ability is not sufficient. In order to further enhance the ultraviolet shielding effect, the paint of Comparative Example 1 can be applied thicker, but in this case, in order to apply thicker,
It is not possible to select a coating method that is inexpensive and suitable for mass production, such as offset printing or gravure printing, and if a thick coating is applied using a screen printing method, etc., the coating cost will increase significantly, and organic ultraviolet absorbers are Most of them have a yellow to brown color due to their structure, and when the film thickness is increased or the concentration is increased, the color develops and the vividness of the color is lost, which is not compatible with the purpose of preventing fading using an overcoat. Become stronger.

Regarding the spectral transmission curve of the paint of Comparative Example 2, the transmittance is low mainly in the visible region, and there is a drawback in terms of transparency. In addition, the ultraviolet absorption edge is located on the shorter wavelength side compared to the paint for antifading coating film example 1, that is, the amount of ultraviolet light transmitted increases, which is disadvantageous in terms of antifading effect.

Next, excluding the organic ultraviolet absorber in the formulation of Comparative Example 3,
Other than that, a fluorescent pigment-containing paint was prepared using the same formulation and the same operation, and this paint was applied onto a PET film (12 μm thick) to a dry film thickness of 3 μm and dried.

Next, the coated surfaces were overcoated with the paints of Coating Example 1 and Comparative Example 1 for anti-fading coatings with a bar code to a dry film thickness of 3 μm to provide samples and comparative samples.

Next, the paint containing the organic ultraviolet absorber obtained in Comparative Example 3 was applied onto a PET film (12 μmW) and dried to a dry coating thickness of 3 μm. The samples obtained in this way and comparative samples that were not overcoated with the anti-fading composition and did not contain organic ultraviolet absorbers were collected outdoors at our laboratory in Funabashi City, Chiba Prefecture from February 1989 to February 1990. We conducted an outdoor exposure test for about 1 year and compared the results with non-exposed conditions every certain number of days.
The color difference dE was measured in comparison with the unirradiated sample. The results are shown in Table 2.

The results of the fading property in the outdoor exposure test shown in Table 2 show that Sample No. 1 without top coating and Sample No. 4 containing an organic ultraviolet absorber of Comparative Example 3 have extremely fast fading speeds and are not suitable for outdoor use. I know it's not suitable. Further, Sample No. 3, which was overcoated with the paint of Comparative Example 1, has an effect when compared with Sample No. 1.4, but compared with Sample No. 2, the fading prevention effect is small and cannot be said to be sufficient. On the other hand, sample number 2
The fading was significantly improved compared to the uncoated one, and after one year of outdoor exposure, the dE of anti-fading paint Example 1/the dE of the uncoated one was 1/6 times that of yellow and 1/9 times that of orange. The color fading was suppressed to 115 to 1/9 times as much as red, showing a remarkable anti-fading effect.

As mentioned above, the anti-fading paint Example 1, which contains particulate zinc oxide, has excellent transparency (see Figure 1), so it does not impair the color tone of the underlying fluorescent pigment at all. Therefore, it is considered to be optimal as a fading prevention coating for top coating.

On the other hand, in the method of overcoating a paint containing an organic UV absorber (Comparative Example 1) or adding an organic UV absorber directly to a paint containing a fluorescent pigment (Comparative Example 3), The effect of inhibiting discoloration is insufficient.

In addition, for PET films (thickness 12 μm) coated with anti-fading coatings prepared in Paint Examples 1 and 2 and Comparative Examples 1 and 2 to a dry film thickness of 3 μm, total light transmittance, 365 nm transmittance, The haze values are shown in Table 1.

Paint example 18 Paint example 28 Comparative example 18 Comparative example 25 8% 0.0 0.1 8% 0.0 0.1 8% 39.4 0 15% 3
, 3 19.2 [Effects of the Invention] As explained above, the antifading composition of the present invention contains zinc oxide fine particles with a particle size of 0.1 μm or less in the solid content of the paint.
90% by weight dispersed in a binder with a haze of 10 or less, the coating film is used as an ultraviolet shielding layer as an anti-fading composition for fluorescent and phosphorescent dyes and pigments, as well as metal oxide fine particles. This anti-fading paint for fluorescent or phosphorescent dyes and pigments is composed of a transparent liquid in which pigments are dispersed, and the following remarkable technical effects have been obtained.

First, if it is applied to the surface of a base material containing fluorescent or phosphorescent dyes or pigments, which have traditionally been difficult to use outdoors because they are easily degraded by ultraviolet rays, even gravure printing, offset printing, etc. Even with a thin film that can normally be formed, for example, 5 μm or less, a coating film that sufficiently blocks ultraviolet rays over a wide range and at the same time transmits visible light well can be formed, so fluorescent, phosphorescent dyes, At the same time, the color tone of the pigments is not impaired, and at the same time, their fading is significantly suppressed, making it extremely easy to use fluorescent and phosphorescent dyes and pigments outdoors.

Second, products that traditionally tended to be limited to indoor applications,
Using a coating method that is relatively inexpensive and suitable for mass production, the anti-fading composition of the present invention and its coating material will greatly expand the field of application of fluorescent and phosphorescent dyes and pigments to a wide range of outdoor applications. By significantly increasing its utility value, the anti-fading composition of the present invention is extremely useful.

Thirdly, this results in the provision of economical anti-fading compositions for fluorescent and phosphorescent dyes and pigments, as well as their coatings, which make it possible to maintain the added value of objects for a longer period of time. Ta.

No. ! figure

[Brief explanation of the drawing]

FIG. 1 is a graph showing the spectral transmittance curve of the coating film used in the anti-fading composition of the present invention in comparison with a comparative example. Patent applicant: Sumitomo Cement Co., Ltd. Agent: Hiroshi Kuramochi, patent attorney

Claims (1)

[Scope of Claims] 1. An anti-fading composition comprising a transparent film in which UV-shielding metal oxide fine particles are dispersed on the surface of a substrate containing a fluorescent or phosphorescent dye or pigment. 2. An anti-fading paint for fluorescent or phosphorescent dyes and pigments, characterized by comprising a transparent liquid in which ultraviolet-shielding metal oxide fine particles are dispersed. 3. The anti-fading composition according to claim 1, wherein the metal oxide fine particles are zinc oxide. 4. The anti-fading composition according to claim 3, wherein the particle size of the zinc oxide is 0.1 μm or less. 5. The content of the zinc oxide in the solid content of the paint is 5 to 9.
4. The anti-fading composition according to claim 3, wherein the content is 0% by weight. 6. Claim 1, wherein the transparent film has a haze of 10 or less.
The anti-fading composition described in Section 1.