JPH1088025A - Phosphorescent particle and phosphorescent road marking material made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phosphorescent particle which can reduce the amt. of the phosphorescent pigment to be used and possesses high luminescence brightness and excellent visibility in a dark place by coating the surface of an inorg. or org. particle having a total light transmittance of not less than 50% with a phosphorescent pigment. SOLUTION: A phosphorescent pigment is applied onto the surface of an inorg. particle (a glass particle) or an org. particle (a synthetic resin particle) having a total light transmittance of not less than 50% to prepare a phosphorescent particle which can reduce the amt. of the phosphorescent pigment to be used and possesses high luminescence brightness and excellent visibility in a dark place. This particle is used to form a phosphorescent road marking material. Glass particles usable herein include, e.g. particles of soda lime glass, borosilicate glass, and potash glass. Synthetic resin particles usable herein include particles of (meth)acrylic resin and epoxy resin. According to the above constitution, light energy of sunlight or an electric light is effectively absorbed or stored in the phosphorescent pigment, the amt. of the phosphorescent pigment to be used may be smaller than that in the prior art, the luminescence brightness is high, and the visibility in a dark place is excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to luminous particles and luminous road marking materials using the same.

[0002]

2. Description of the Related Art Conventionally, luminous pigments have been used as means for obtaining visibility in a dark place. Luminescent pigments are
It absorbs and stores the light energy of sunlight and electric lights, and releases the energy again as light over several hours.It is contained in various products such as paints and adhesive tapes for display at night or in the dark. .

For example, Japanese Patent Application Laid-Open No. 52-89137 discloses that a thermoplastic resin contains zinc sulfide / copper (ZnS / Cu).
There has been proposed a heat-welding luminous paint obtained by adding a luminous pigment (a luminous powder) and a pigment having an arbitrary color tone as required and uniformly mixing them.

In this type of conventional display material, in order to ensure visibility in a dark place, it is necessary to increase the concentration of the luminous pigment to sufficiently increase the emission luminance. . This is because the emission luminance is proportional to the concentration of the luminous pigment to some extent.

[0005]

However, luminous pigments are very expensive, and when they are used, for example, in the production of luminous road marking materials, a large amount of luminous pigment is added to the road marking material to reduce the concentration. If the light emission luminance is further increased sufficiently, there is a problem that the cost of the luminous road marking material becomes extremely high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the invention is to use a small amount of a luminous pigment to obtain luminous particles having high luminous luminance and excellent visibility in a dark place. And a luminous road marking material using the same.

[0007]

The above object can be achieved by luminous particles formed by coating a luminous pigment on the surface of inorganic or organic particles having a total light transmittance of 50% or more. Item 1 invention)

The above object can be achieved by the luminous road marking material using the luminous particles (the invention of claim 2).

In the present invention, the total light transmittance is 50%.
As the above inorganic or organic particles, usually, glass particles or synthetic resin particles having a total light transmittance of 50% or more are used.

[0010] Glass particles include silicic acid (silicon dioxide), sodium oxide (anhydrous sodium carbonate turned into sodium oxide in glass, soda ash), and lime oxide (calcium carbonate turned into calcium oxide in glass) ), Inorganic particles containing magnesium oxide, barium oxide, alumina, lead oxide, potassium oxide, boric acid, lithium oxide, titanium oxide, and zinc oxide as main components. For example, particles made of soda lime glass, lead crystal glass, borosilicate glass, aluminosilicate glass, potash glass, glass ceramic, and the like are included.

The synthetic resin particles are not particularly limited as long as they have a total light transmittance of 50% or more. For example, polyvinyl chloride, polyvinylidene chloride, (meth) acrylic resin, epoxy resin, styrene resin, polyurethane, polycarbonate, fluorine resin, acrylic silicone resin, petroleum resin, urethane-modified alkyd resin, maleic acid-modified rosin ester, cumarone indene Examples include particles made of resin, terpene resin, unsaturated polyester, and the like.

Among these synthetic resin particles, particles composed of a (meth) acrylic resin, an epoxy resin, and a styrene resin, which are particularly excellent in transparency, are preferred.

Specific examples of the above (meth) acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate and octyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, (meth) acrylic acid, N
-Methyl (meth) acrylamide, N-methyl (meth)
Acrylamide, N, N-diethyl (meth) acrylamide, (meth) acrylonitrile, hydroxy (meth)
Homopolymers and copolymers polymerized from acrylates and the like are preferred.

As the epoxy resin, specifically,
Homopolymers and copolymers polymerized from glycidyl ethers of phenols such as bisphenol A, bisphenol F and phenol novolac, glycidyl ethers of alcohols such as ethylene glycol and propylene glycol, and glycidyl ethers such as phthalic acid are preferred.

As the styrene resin, specifically,
Styrene, o-methylstyrene, m-methylstyrene,
Homopolymers and copolymers polymerized from alkylstyrene such as p-methylstyrene, α-methylstyrene, ethylstyrene, dimethylstyrene, butylstyrene and the like, and chlorostyrene are preferred.

Here, the shape of the inorganic or organic particles is as follows:
Although not particularly limited, spherical ones are desirable. This is because the internal reflection of light that has penetrated into the inorganic or organic particles can be effectively used in all directions.

The size (diameter) of the inorganic or organic particles is not particularly limited, but is preferably 10 μm or more.
20 μm or more is more preferable. The size of this particle is 1
If the thickness is less than 0 μm, the particles of the luminous pigment coated thereon may be too small to obtain a high emission luminance, and the effect of the present invention may not be sufficiently obtained.

The total light transmittance of the inorganic or organic particles is 5
If the total light transmittance is less than 50%, high luminous luminance cannot be obtained with a small amount of luminous pigment, and the effect of the present invention cannot be sufficiently obtained. In particular, the total light transmittance is preferably 70% or more.

The surface of such inorganic or organic particles is coated with a luminous pigment. Here, the luminous pigment is composed of a substance having a phosphorescence phenomenon, absorbs and accumulates light such as sunlight or electric light, gradually releases the accumulated light to emit light, and absorbs light-accumulates-emits light. It means something that can be repeated many times.

Such luminous pigments include calcium sulfide / bismuth (Ca), which has been widely used in the past.
S / Bi), strontium / bismuth based on calcium sulfide [(Ca, Sr) S / Bi), based on zinc sulfide / copper (Z
nS / Cu), zinc sulfide / cadmium / copper [(Zn,
Cd) S / Cu] can be used.

However, from the viewpoints of luminous performance such as environmental aspects, luminous luminance and luminous time, weather resistance and long-term stability, metal oxides such as alumina, strontium oxide, barium oxide, calcium oxide and cerium oxide and Eu (europium). ), Dy (dysprosium), Lu (lutetium),
It is preferable to use a luminous pigment obtained by firing a rare earth element such as Tb (terbium). Examples of such a luminous pigment include "N Night Luminous Nova" manufactured by Nemoto Special Chemical Co., Ltd., and "Chemicolor NL" manufactured by Nippon Chemix.

The shape of the particles of these luminous pigments is not particularly limited. The size (diameter) of the particles is determined by the size of the above-mentioned inorganic or organic particles covering the luminous pigment, and is generally 0.001 of the size of the inorganic or organic particles.
The range is preferably from 1.0 to 1.0 times, and more preferably from 0.01 to 1.0 times. Inorganic or organic particles having a size of 0.
If it is less than 001 times, the particles of the luminous pigment aggregate and become difficult to disperse, and it becomes difficult to coat the surface of the inorganic or organic particles. It may be detached from the surface of the organic particles.

The amount of the luminous pigment coated on the surface of the inorganic or organic particles depends on the kind of the luminous pigment to be used and the size of the particles. The area ratio is preferably in the range of 20 to 100%, more preferably in the range of 40 to 100%. If the area ratio is less than 20%, the absolute amount of the luminous pigment will be insufficient, and it will be difficult to obtain sufficient light emission luminance.

For calculating the coating amount (area ratio) of the luminous pigment, for example, a photograph of the coated particle surface is taken with a scanning electron microscope (elemental mapping may be used), and image processing is performed. Approximately.

The thickness of the coating layer of the luminous pigment also depends on the type of the luminous pigment used and the size of the particles.
Generally, it is preferably in the range of 10 to 1000 μm, more preferably in the range of 20 to 800 μm. If the thickness of the coating layer is less than 10 μm, the diameter of the luminous pigment becomes small, making it difficult to obtain sufficient light emission luminance.
When the thickness exceeds 0 μm, the concealing rate of the coating layer becomes large, and even if the thickness is further increased, the emission luminance is not improved and the cost is increased.

As a method of coating the surface of the inorganic or organic particles with the luminous pigment, a luminous pigment is added to a solvent together with a binder resin, the binder resin is dissolved, and the luminous pigment is sufficiently mixed and dispersed to form a coating solution. A method (dipping method) in which inorganic or organic particles are immersed therein and then dried to obtain a coating (dipping method) is employed.

When the surface of inorganic particles such as glass is coated with a luminous pigment, it is preferable to use a butyral resin having good adhesion to glass as the binder resin. When coating the luminous pigment on the surface of the organic particles such as a synthetic resin, as the binder resin, a resin having good compatibility with the synthetic resin constituting the organic particles is used. Selected.

The solvent for dissolving the binder resin depends on the type of the synthetic resin constituting the organic particles, but is appropriately selected from toluene, ethyl acetate, methyl ethyl ketone, tetrahydrofuran, methanol, acetone, hexane, dimethyl sulfoxide and the like. Selected.
In this case, the thickness of the coating layer can be set by changing the solution concentration, the immersion time, and the like.

As another method of coating the surface of the inorganic or organic particles with the luminous pigment, the solution prepared as described above is sprayed on the surface of the inorganic or organic particles and then dried to be coated. A method (spray method) can also be adopted.

In the above dipping method and spraying method, a binder resin is present together with the luminous pigment after coating. When the surface of inorganic particles such as glass is coated with a luminous pigment, the particles may be coated with a dipping method and a spray method, and then heated to remove the binder resin by incineration.

Further, as another method of coating the surface of the inorganic or organic particles with the luminous pigment, a method of blasting the surface of the inorganic or organic particles with the luminous pigment by a gun at a high speed (blast method) is also employed. Is done. Since the blast method does not require a binder resin, it is suitable for coating the surface of an organic particle such as a synthetic resin with a luminous pigment.

In this way, luminous particles obtained by coating the luminous pigment on the surface of organic or inorganic particles having a total light transmittance of 50% or more are obtained (the invention of claim 1).

Such luminous particles are thinly coated on the surface of the organic or inorganic particles, and almost all luminous pigments are considered to contribute to light emission. There are many luminous pigments that cannot contribute to light emission due to the concealing property of the luminescent pigment itself.)

That is, light that has penetrated the gaps between the coated luminous pigments and the inside of the organic or inorganic particles through the thin coating layer is different from the position where the light was complicatedly reflected and incident on the inner surfaces of the organic or inorganic particles. It is presumed that light is also supplied to the luminous pigment present at the position, and light energy is effectively absorbed and stored in the luminous pigment, as compared to the case of only the luminous pigment, and light is efficiently emitted. .

Such luminous particles are used for luminous paints, luminous adhesive tapes, luminous road marking materials and the like, as in the case of conventional luminous pigments, and are particularly preferably used for luminous road marking materials. (The invention of claim 2).

The luminous road marking material is used as a luminous pigment.
Except that the luminous particles of the present invention are used, the configuration can be the same as that of the conventional luminous road marking material. Examples of such a luminous road marking material include, for example, a single-layer luminous road marking material formed of a luminous resin layer containing the luminous particles of the present invention, or a road marking material. A luminous road marking material having a multilayer structure in which only the vicinity of the surface is formed of the luminous resin layer containing the luminous particles of the present invention is exemplified.

The resin used for the luminous resin layer is not particularly limited as long as it satisfies the physical properties required for road marking, mainly tensile strength, bending strength, abrasion resistance, weather resistance, durability and the like. Not done. However, it is desirable to use a resin having transparency for the phosphorescent resin layer containing phosphorescent particles. Particularly, a (meth) acrylic resin, an epoxy resin, and a styrene resin having excellent transparency are preferable.

The luminous road marking material is JIS K5
665 A road marking paint (white or yellow traffic paint) according to one, two or three types is applied to the road surface, and while the paint is in a softened or molten state,
It can also be obtained by scattering and adhering the luminous particles of the present invention. In this case, it is advantageous in terms of cost.

The total thickness of the luminous road marking material is 0.5 m.
m or more, more preferably 0.7 mm or more.
If the total thickness is less than 0.5 mm, strength and durability may become problems.

The luminous resin layer may not be formed on the entire surface but may be formed partially on the surface. In addition, the light-storing resin layer may contain glass beads or the like having reflex reflection properties together with the light-storing particles.

In the luminous road marking material, a white or yellow coloring pigment is usually compounded in any of the layers. Examples of these coloring pigments include titanium oxide and chrome yellow, and if necessary, other coloring pigments, dyes,
Metal powders such as aluminum flakes, nickel powders, gold powders, and silver powders can also be added.

If necessary, a filler such as calcium carbonate, talc powder, silica powder, glass fiber, mica, talc, etc., paraffin wax for improving stain resistance,
A lubricant such as microcrystalline wax and polyethylene wax, an antioxidant, an ultraviolet absorber, and a curing agent are also blended.

When these various compounding agents are blended in the luminous resin layer, they must be blended to such an extent that the transparency of the luminous resin layer is not impaired and the luminous resin layer is not opaque.

Further, the luminous resin layer on the surface of the luminous road marking material may be coated with a transparent resin in order to prevent the luminous particles from separating or to protect the luminous particles. In addition, EVA (ethylene-vinyl acetate copolymer), SIS (styrene-isoprene block-styrene block copolymer), An adhesive layer such as an acrylic-based hot melt adhesive, an acrylic-based pressure-sensitive adhesive, or a heat- or ultraviolet-curable acrylic adhesive may be provided.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, advantages of the present invention will be described with reference to examples and comparative examples of the present invention. Example 1 Luminescent pigment having an average particle size of 60 μm (N Luminescent Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd. was classified,
3.6) was added to a methanol solution of butyral resin, and the mixture was sufficiently stirred to mix and disperse the luminous pigment.
A dispersion of the phosphorescent pigment was prepared.

The dispersion of the luminous pigment has a diameter of 300
μm (± 20 μm) glass beads (classified from Unibeads UB108L manufactured by Union Co., specific gravity: 2.5) are introduced, the glass beads are taken out, and they are sufficiently dried in a drying oven to form a coating layer. The thickness of about 60
Luminescent particles of μm were obtained (dipping method). The coating amount of the luminous pigment was 9 in area ratio to the entire surface of the glass beads.
4%.

A container (15 cm × 15 cm) made of a transparent acrylic plate having a thickness of 5 mm using the obtained phosphorescent particles.
To form a layer of luminous particles having a thickness of 3 mm, which was used as a sample for evaluating visibility (luminance).

The above-mentioned sample for evaluation was fixed on a horizontal table, and two fluorescent lamps (40 W × 2) were irradiated with light from a distance of 1 m from above vertically for 100 minutes. The evaluation sample was placed in the dark, and the visibility (luminance) was evaluated visually at a position 20 m away from a position at a height of 1.5 m. After the irradiation, the evaluation sample was left in the dark for 6 hours, and the visibility (luminance) was evaluated visually from a point 20 m away. Table 1 shows the results.

Example 2 Luminescent pigment having an average particle diameter of 60 μm was formed on the surface of glass beads having a diameter of 1000 μm (± 20 μm) (classified from Unibeads UB1921S manufactured by Union Co., specific gravity 2.6) by a dipping method. (N luminous Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd., specific gravity: 3.6), and the thickness of the coating layer is about 60 μm.
m phosphorescent particles were obtained. The coating amount of the luminous pigment was 98% in area ratio to the entire surface of the glass beads.

The visibility (luminance) was evaluated in the same manner as in Example 1 using the above-mentioned phosphorescent particles. Table 1 shows the results.

(Example 3) Glass beads having a diameter of 35 μm (± 5 μm) (classified from Unibeads UB02NH manufactured by Union Co., specific gravity 4.5) by a dipping method.
Is coated with a luminous pigment having an average particle size of 30 μm (N Luminescent Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd., specific gravity 3.6), and a luminous particle having a coating layer thickness of about 60 μm is coated. Obtained. The coating amount of the luminous pigment was 70% in area ratio with respect to the entire surface of the glass beads.

The visibility (luminance) was evaluated in the same manner as in Example 1 using the phosphorescent particles. Table 1 shows the results.

(Example 4) By a dipping method, glass beads having a diameter of 1.5 mm (± 0.15 mm) (classified from Unibeads UB2123S manufactured by Union Co., specific gravity: 2.6) were coated on the surface with an average particle diameter of 100 μm. Luminous pigment (N Luminescent Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd., specific gravity: 3.6), and the thickness of the coating layer is about 5
Luminescent particles of 00 μm were obtained. The coating amount of the luminous pigment is
The area ratio was 99% with respect to the entire surface of the glass beads.

The visibility (luminance) was evaluated in the same manner as in Example 1 using the above luminous particles. Table 1 shows the results.

Example 5 The surface of glass beads having a diameter of 1.5 mm (± 0.15 mm) (classified from Unibeads UB2123S manufactured by Union Co., specific gravity 2.6) was dipped by the dipping method to an average particle diameter of 30 μm. Luminous pigment (N Luminescent Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd., specific gravity: 3.6), and the thickness of the coating layer is about 1
Luminescent particles of 50 μm were obtained. The coating amount of the luminous pigment is
The area ratio was 99% with respect to the entire surface of the glass beads.

Using the above luminous particles, visibility (luminance) was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 6 A 500 μm diameter (±) made of a methyl methacrylate-butyl methacrylate copolymer
20μm) acrylic beads (specific gravity 1.0)
Luminescent pigment with an average particle size of 60 μm (N
Classification of Luminescent Luminova G300, specific gravity 3.6)
With a gun at a high speed, about 200
Luminescent particles were obtained by coating to a thickness of μm (blast method). The coating amount of the luminous pigment was 99% in area ratio with respect to the entire surface of the resin beads.

The visibility (luminance) was evaluated in the same manner as in Example 1 using the above luminous particles. Table 1 shows the results.

Example 7 Polystyrene having a diameter of 6
00 μm (± 20 μm) styrene beads (specific gravity 1.
On the surface of 0), a luminous pigment having an average particle size of 60 μm (classified N Luminescent Luminova G300 manufactured by Nemoto Special Chemical Co., Ltd., specific gravity: 3.6) is spun at a high speed with a gun to have a thickness of about 200 μm. To obtain phosphorescent particles (blast method). The coating amount of the luminous pigment was 98% in area ratio with respect to the entire surface of the resin beads.

Using the above luminous particles, visibility (luminance) was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 8 A road marking paint (white traffic paint) according to JIS K5663 is melt-coated on a concrete plate assuming a road surface, and obtained in Example 1 while the paint is in a molten state. The luminous particles thus obtained were sprayed, and the length was 15 cm × width 30 cm × thickness 1.6 mm.
Luminous road marking material was formed.

The visibility (luminance) was evaluated in the same manner as in Example 1 using the luminous road marking material as an evaluation sample. Table 1 shows the results.

(Comparative Example 1) As the luminous particles, 145 luminous pigments having an average particle diameter of 60 μm (classified from N Luminescent G300 manufactured by Nemoto Special Chemical Co., specific gravity 3.6) were used.
g was prepared (this corresponds to the total amount of the luminous pigment in the luminous particles used in the evaluation sample of Example 1).

A container (15 cm long × 15 cm wide) made of this conventional luminous pigment with a transparent acrylic plate having a thickness of 5 mm.
m) without gaps to form a 1.7 mm-thick luminous pigment layer, which was used as a sample for evaluation of visibility (luminance). Otherwise, visibility (luminance) was evaluated in the same manner as in Example 1. Table 1 shows the results.

[0065]

[Table 1]

[0066]

According to the luminous particles of the present invention, luminous pigments are coated on the surfaces of inorganic or organic particles having a total light transmittance of 50% or more, whereby the light energy of sunlight or electric lamps is luminous. The pigment is effectively absorbed and luminous stored, and light is emitted efficiently.As a result, compared to conventional luminous pigments, a small amount of luminous pigment is used, resulting in higher luminous brightness and higher visibility in dark places. Excellent.

The luminous particles of the present invention are effective when contained in various products such as paints, adhesive tapes and road marking materials for display at night or in the dark. In particular, in the field of luminous road marking materials that require a large amount of expensive luminous pigments, luminous road marking materials using luminous particles of the present invention are luminous road marking materials using conventional luminous pigments. By using a small amount of the luminous pigment as compared with the material, the emission luminance is high and the visibility in a dark place is excellent.

Accordingly, the luminous road marking material using the luminous particles of the present invention can be used to reduce the cost of strips, symbols, and characters such as lane markings, stop lines, pedestrian crossings and danger points. This has the advantage that it can be marked with.

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Claims (2)

[Claims] 1. Luminescent particles obtained by coating the surface of inorganic or organic particles having a total light transmittance of 50% or more with a luminous pigment. 2. A luminous road marking material using the luminous particles according to claim 1.