JP2000154325A - Exterior material for portable electrical equipment having photochromism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an exterior material for portable electrical equipment reversibly changing colors according to the kinds of the light source, having large tone change and capable of expressing colors which is unobtainable conventionally by compounding a specific fine particles of oxides of rare earth elements to a transparent thermoplastic resin. SOLUTION: The material comprises the composition including (A) transparent thermoplastic resin (preferably; polycarbonate resin, acrylic resin, transparent ABS resin, urethane resin or the like) compounded with (B) the fine particles of oxides of rare earth elements of formula M2O3 (M is Ho, Nd or Pr) having average particle size of 5 to 100 nm. The preferable compounding amount of the component (B) in this composition is 0.5 to 15 wt.%. This composition is preferably compounded with 1% or less of coloring agent (C). The surface of portable electrical equipment is printed or coated with ink or a paint including epoxy resin or acrylic resin or the like as the resin and the component (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exterior member for portable electric equipment having reversible discoloration, and its color is reversibly changed according to the type of an external light source, and its color tone is largely changed. An exterior member is provided.

[0002]

2. Description of the Related Art Photochromic molecules, which are organic compounds, have been known as substances which cause the color of a compound to be reversibly changed by light irradiation. Photochromic molecules change their chemical structure by absorbing energy from light irradiation, and as a result, the color of the compound changes. Further, among inorganic compounds, oxides of Ho, Nd, and Pr are known. These oxides have a special reflection spectral distribution, and the color of the oxide changes according to the type of light source such as sunlight or a fluorescent lamp.

[0003]

However, when such photochromic molecules are used as a dye material, the reversibility of the color change is often incomplete, and the time required for the color change is long. In addition, repetition of color change due to light absorption causes light deterioration such as loss of reversibility of color change, and reversibility of light change often disappears due to heat or long-term UV irradiation. Not suitable for storage. On the other hand, the rare earth oxides of the inorganic compounds Ho, Nd, and Pr have good qualities such as weather resistance and heat resistance, but their color change is small and can be expressed only within a limited range.

[0004] In view of the above problems, the present inventor has considered that the color reversibly changes according to the type of light source, and the color tone changes greatly, which cannot be obtained with conventional materials. An object of the present invention is to provide an exterior member for a portable electric device capable of expressing a color.

[0005]

According to the present invention, there is provided an exterior member for a portable electric device, comprising a transparent thermoplastic resin having a general formula M2 O3 having an average particle diameter in a range of 5 to 100 nm (where M is Ho, (Representing Nd or Pr). The present invention provides an exterior member for a portable electric device having reversible discoloration, comprising a composition containing rare-earth oxide ultrafine particles represented by the following formula:

Further, according to the present invention, a surface of an exterior member for a portable electric device is represented by a general formula M2O3 (where M represents Ho, Nd or Pr) having an average particle diameter in a range of 5 to 100 nm. An object of the present invention is to provide an exterior member for a portable electric device having reversible discoloration characterized by being printed or painted with an ink or paint containing ultra-fine rare earth oxide particles.

The rare earth oxide ultrafine particles of the present invention have a reflection spectral distribution different from that of conventional rare earth oxide fine particles. As an example, a conventional Ho2 having an average particle diameter of about 2 μm is used.
Comparing the reflection spectral distribution of the O3 fine particles with the reflection spectral distribution of the Ho2 O3 ultrafine particles having an average particle diameter of 30 nm, it has a major absorption peak in the wavelength range around 460 nm, 540 nm and 650 nm regardless of the particle diameter. 540n
m, the reflectance in the wavelength region around 650 nm is
% Or more, the ultrafine particles have a reflectivity of 20 to 30%, exhibit extremely large absorption, and reflectivity in the wavelength region of the two absorption peaks is significantly different.

As a result, 490 nm, 550 nm, 62
When Ho2 O3 particles are illuminated on a three-wavelength emission fluorescent lamp having a large emission line near 0 nm, the Ho2 O3 ultrafine particles absorb more wavelengths around 540 nm and 650 nm and are included in the three-wavelength emission fluorescent lamp. Since the bright line near 620 nm is reflected, the color tone of the Ho2 O3 ultrafine particles becomes stronger in red, and as a result, a deep pink color can be expressed.

[0009]

Embodiments of the present invention will be described with reference to the following examples. In the present invention, a general formula M2 O3 (where M is Ho, Nd or Pr) blended in a transparent thermoplastic resin molded as an exterior member for a portable electric device.
The amount of the rare earth oxide ultrafine particles represented by
It can be 1 to 15% by weight, preferably 2 to 10% by weight.

The composition containing the rare earth oxide ultrafine particles may contain a colorant in an amount of 1% by weight or less. The amount of the coloring agent having a high light-shielding property is preferably 0.1% by weight or less, more preferably 0.05% by weight or less. By doing so, color variation can be achieved by a combination of discoloration due to the absorption peak of the rare-earth oxide ultrafine particles and coloring of the colorant.
For example, when Ho2 O3 ultrafine particles and a yellow pigment are blended in the transparent resin component, the color is yellow as it is when exposed to sunlight, but it exhibits a light orange color when exposed to the fluorescent light of the standard light source D65, and has a three wavelength range. The fluorescent lamp emits orange light.

As the above-mentioned transparent thermoplastic resin, besides polycarbonate resin, acrylic resin, transparent ABS resin, urethane resin, AS resin and transparent HI polystyrene resin, transparent engineering resin such as polyester resin can also be used. In addition, a resin having good transparency has good discoloration, but a translucent resin can also be used.

Further, according to the present invention, a resin or metal exterior member for portable electric equipment has an average particle diameter of 5 to 1
It can also be carried out by printing or painting with an ink or paint containing ultra-fine particles of rare earth oxide represented by the general formula M2 O3 (wherein M represents Ho, Nd or Pr) in the range of 00 nm. .

As the resin component constituting the above-mentioned ink or paint, a transparent curable resin such as an epoxy resin, an acrylic resin, a urethane resin or a fluorine resin is preferable, and is blended with these resin components. The compounding amount of the rare earth oxide ultrafine particles is preferably in the range of 10 to 60% by weight based on the solid content. Furthermore, a small amount of a colorant of 5% by weight or less can be blended.

The portable electric equipment used in the present invention includes a portable telephone including a pager, a PHS, etc., a cassette,
Examples thereof include portable music reproducing devices such as CD and MD systems, video cameras, digital cameras, portable game machines, portable personal computers, and the like, and are used as exterior members of these devices.

[0015]

EXAMPLES Example 1 and Comparative Example 1 An average particle size of 30% was added to 95% by weight of a polycarbonate resin.
A composition containing 5% by weight of ultrafine Ho2O3 particles having a thickness of 5 nm was injection-molded to form an exterior member for a mobile phone. The exterior member exhibits a light yellow color when exposed to sunlight, a light pink color when exposed to a fluorescent lamp of the standard light source D65, and a deep pink color when exposed to a three-wavelength band fluorescent lamp. On the other hand, Ho2 O3 having an average particle size of about 8 μm
In the case of an exterior member manufactured by the same method using fine particles, when exposed to a three-wavelength-range fluorescent lamp, it has a dark flesh color. Thus, using the Ho2O3 ultrafine particles of the present invention could not be expressed conventionally. It is possible to express colors.

Example 2 and Comparative Example 2 A composition in which 8% by weight of ultrafine Pr2O3 particles having an average particle diameter of 30 nm were mixed with 92% by weight of methyl methacrylate resin was injection molded to form an exterior member for a portable game machine. . The exterior member exhibits a pale yellow color when exposed to sunlight, a yellowish green color when exposed to a fluorescent light of the standard light source D65, and a deep yellowish green color when exposed to a three-wavelength band fluorescent lamp. On the other hand, Pr having an average particle diameter of about 10 μm
In the case of an exterior member manufactured by the same method using 2O3 fine particles, when exposed to a three-wavelength region fluorescent lamp, the exterior member has a pale yellow-green color. Thus, when the Pr2O3 ultrafine particles of the present invention are used, a darker color is obtained. It exhibits a yellow-green color and makes it possible to obtain a larger change in color tone.

Example 3 and Comparative Example 3 A composition comprising 95% by weight of transparent HI polystyrene resin and 5% by weight of ultrafine Nd2O3 particles having an average particle diameter of 30 nm was injection-molded to form an exterior member for a portable game machine. did. This exterior member exhibits a light mauve color when exposed to sunlight, and exhibits a deep blue color when exposed to the fluorescent lamp of the standard light source D65 and the three-wavelength band fluorescent lamp. On the other hand, an exterior member manufactured by the same method using Nd2O3 fine particles having an average particle size of about 7 .mu.m has a light blue color when exposed to a three-wavelength band fluorescent lamp.
When 2O3 ultrafine particles are used, a deeper blue color is exhibited, and a larger change in color tone can be obtained.

Example 4 and Comparative Example 4 50 parts by weight of ultrafine particles of Ho2 O3 having an average particle diameter of 30 nm were added to 50 parts by weight (solid content) of a thermosetting transparent resin ink containing an epoxy resin as a main component. Compounded and dispersed. At that time, a solvent containing ethylene glycol monobutyl ether as a main component was added to adjust the viscosity. Using the above ink, screen printing is performed on the surface of the exterior member of the portable MD player made of metal and baked at 150 ° C. for 30 minutes to obtain a cured film having a reversible discoloration of 60 μm in thickness. An exterior member having a layer was obtained. This exterior member has a light yellow color when exposed to sunlight, and has a standard light source D65.
When exposed to a fluorescent lamp, the light pink color is exhibited, and when exposed to a three-wavelength band fluorescent lamp, the light pink color is exhibited.
On the other hand, the exterior member produced by the same method using Ho2 O3 fine particles having an average particle diameter of about 8 .mu.m had a dark flesh color when exposed to a three-wavelength band fluorescent lamp.

[0019]

As described in detail above, according to the present invention, it is possible to exhibit a large color change in an environment with different light sources, and the ultrafine particles of the present invention change the color tone more than the fine particles of the same compound. Thus, it is possible to express a color which has not existed conventionally. In addition, the color change is due to the absorption and reflection characteristic of rare earth oxides, so the reversibility of the color change is perfect, the speed of the color change is fast, and there is no light deterioration, so the quality such as weather resistance and heat resistance is good. There are advantages. Further, there is an advantage that a color variation is possible by combination with a coloring agent.

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Claims (10)

[Claims] 1. The transparent thermoplastic resin has an average particle diameter of 5 to 5.
The general formula M2 O3 in the range of 100 nm (where M
Represents a composition of rare-earth oxide ultrafine particles represented by Ho, Nd or Pr), wherein the exterior member has a reversible color change property. 2. The portable electric device having reversible discoloration according to claim 1, wherein the compounding amount of the ultrafine rare earth oxide particles in the composition is in the range of 0.5 to 15% by weight. Exterior members. 3. The exterior member for a reversibly discolorable portable electric device according to claim 1, wherein a colorant is incorporated in the composition in an amount of 1% by weight or less. . 4. The method according to claim 1, wherein the transparent thermoplastic resin is at least one of a polycarbonate resin, an acrylic resin, a transparent ABS resin, a urethane resin, an AS resin, and a transparent HI polystyrene resin. An exterior member for portable electric equipment having reversible discoloration. 5. A general formula M2 O3 having an average particle diameter in a range of 5 to 100 nm on a surface of an exterior member for a portable electric device.
(However, M represents Ho, Nd or Pr) Ink or paint containing rare earth oxide ultrafine particles represented by
An exterior member for a portable electric device having reversible discoloration characterized by being printed or painted. 6. The exterior member for a portable electric device having reversible discoloration according to claim 5, wherein the body constituting the exterior member is made of plastic or metal. 7. The resin component constituting the ink or paint is at least one transparent resin component selected from an epoxy resin, an acrylic resin, a urethane resin, and a fluorine resin. The exterior member for a portable electric device having reversible discoloration according to claim 5 or 6. 8. The rare earth oxide ultrafine particles to be blended with the resin component constituting the ink or the paint, in an amount of 10 to 60% by weight of the solid content. An exterior member for a portable electric device having the reversible discoloration described in the above. 9. The reversibly discolorable portable electric device according to claim 5, wherein said ink or paint contains a colorant in an amount of 0.1 to 5% by weight based on solid content. Exterior members. 10. The reversible reversible device according to claim 1, wherein the portable electric device is a portable telephone, a portable music reproducing device, a video camera, a digital camera, a portable game machine, and a portable personal computer. Exterior material for portable electrical equipment with a permanent discoloration.