JPH1160923A - Resin composition for molding illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition excellent in light scattering effect in view of such a disadvantage that although acrylic resins and polycarbonate resins have been widely used as the hoods and canopies of electric illuminators, they are poor in light scattering effect, therefore, irradiated rays of light are hardly transmitted as soft and uniform rays of light. SOLUTION: This resin composition for molding illuminators is obtained by compounding 100 pts.wt. of a thermoplastic polyester resin with 0.05-5.0 pts.wt. of fine calcium carbonate powder 0.5-10 μm in average particle size and 0.05-0.5 pt.wt. of titanium oxide microparticles 0.02-0.5 μm in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting fixture
More specifically, the present invention relates to a resin composition for molding a lighting fixture, which is most suitable for molding a lamp or a shade, and more specifically, a molded product obtained by using the present invention product is a milky white soft scattered light beam that passes through. The present invention provides a resin composition adjusted as described above.

[0002]

2. Description of the Related Art Conventionally, white molded articles exhibiting a light shielding effect have been manufactured by blending silicon oxide or titanium oxide with acrylic resin or polycarbonate resin having excellent transparency and light resistance. It is used as a hood and shade for electric lighting equipment. However, the molded articles obtained by using these resin compositions do not exhibit any light scattering effect, and therefore, the light irradiated on the hood or shade of the electric lighting equipment causes
The outline of the internal light bulb or fluorescent lamp is visible from the outer surface or completely concealed, making it impossible to transmit (irradiate) a soft light beam to the hood or shade.

A molded article using an acrylic resin has a drawback that the mechanical properties are slightly inferior and, when used for a long period of time, cracks are likely to occur at corners and edges, and the molded article is easily damaged. Polycarbonate resins have excellent mechanical properties, but have a high melt-kneading temperature, which limits the additives to be used, and therefore has a sufficient light diffusion effect as compared with acrylic resins. Not being demonstrated. Moreover,
Acrylic resin and polycarbonate resin are both required to have versatility as applications because they have higher specific gravity and higher weight of molded products and higher resin unit price than general-purpose resins such as polyethylene resin and polypropylene resin. It is not preferable as a resin composition for molding a lighting fixture.

In recent years, thermoplastic polyester resins, which have been actively developed for various uses, are general-purpose resins having a low specific gravity and excellent transparency, and have a kneading temperature higher than that of acrylic resins and polycarbonate resins. Since it is low, it is easy to mix dyes and pigments and various additives, and development of molded products for lighting fixtures is also being studied. However, molded articles using these thermoplastic polyester resins do not consider light diffusivity, but merely seek a light (lightly dark) color tone.

[0005] For example, molding of lighting equipment in which titanium oxide is blended with a thermoplastic polyester resin has been attempted.
Conventionally used titanium oxide pigments have an excellent effect on light shielding (hiding), but light diffusion is not considered at all. The effect of passing through the molded product as a soft bright light beam cannot be obtained. As described above, when the titanium oxide pigment is used alone, the glitter (design) represented by gloss and gloss, which is a characteristic of the thermoplastic polyester resin, is completely lost from the surface of the molded product, and the commercial value is significantly reduced. It causes disadvantages and is not preferable from the viewpoint of color and design.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present inventors
When light is applied to the hood, shade, etc. of a lighting fixture molded using a thermoplastic polyester resin having a relatively low specific gravity and good mechanical properties, the light diffuses and becomes soft. In order to obtain a molded article exhibiting an excellent effect of irradiating, it has been studied diligently to combine a specific calcium carbonate and titanium oxide in combination, and found that it solves the above-mentioned disadvantages of the conventional product. .

[0007]

That is, the present invention provides a thermoplastic polyester resin having an average particle size of 0.5 to 10 parts by weight based on 100 parts by weight.
It is a resin composition for molding a lighting fixture, comprising 0.05 to 5.0 parts by weight of a fine calcium carbonate powder of 0.05 μm and 0.05 to 0.5 part by weight of fine titanium oxide particles having an average particle size of 0.02 to 0.5 μm.

The thermoplastic polyester resin used in the present invention is a general-purpose resin having excellent mechanical properties, dimensional stability, heat resistance, etc., and can be used for molding sheets and containers. For example, polyethylene terephthalate and polyethylene naphthalate can be used. As the thermoplastic polyester resin used in the present invention, polyethylene terephthalate having particularly excellent mechanical properties is preferable.

In the molded article obtained by using the resin composition for molding a lighting fixture of the present invention, the irradiated light beam becomes a soft light ray exhibiting a light diffusion effect due to the presence of fine calcium carbonate powder and titanium oxide. When used as a cover or shade, the outline of a fluorescent lamp or a light bulb cannot be seen from the outer surface of the lighting fixture, and the light is transmitted as a soft light beam to the outer surface. The calcium carbonate fine powder (hereinafter abbreviated as calcium carbonate) used as an additive in the present invention may be any of pulverized products such as natural chalk, limestone and marble, and synthetic products obtained by a chemical precipitation method. The particle diameter is preferably 0.5 to 10 μm as an average particle diameter.

[0010] Calcium carbonate having an average particle size of 0.5 to 10 µm exhibits excellent light diffusion and milky white effects in a molded product when blended with a thermoplastic polyester resin due to the relationship of light refraction with the polyester resin. If the particle size of the calcium carbonate is 0.5 μm or less, the milky white effect is reduced, which is not preferable.
Incidentally, the average particle size is measured by a method such as an electron microscope, a sedimentation method, and a transmission method.

The amount of calcium carbonate used is 0.05 parts by weight per 100 parts by weight of the thermoplastic polyester resin (hereinafter abbreviated as “parts”).
Add up to 5.0 parts. If the amount is less than 0.05 part, satisfactory milky white effect and light diffusion effect are not exhibited, which is not preferable.
If the amount is more than 5.0 parts, the milky white effect is not further improved, so that it is not necessary to add more than 5.0 parts. Fine particle titanium oxide (hereinafter abbreviated as titanium oxide) used as an additive in the present invention has a particle size larger than that conventionally used as a coloring agent for products such as paints, coating materials, adhesives and molding materials. A very small one of 0.02 to 0.5 μm is used.

When the titanium oxide used in the present invention is blended with a thermoplastic polyester resin, the titanium oxide exhibits an excellent light diffusion effect which cannot be obtained with conventional titanium oxide pigments.
With this effect, when the particle size is 0.02 μm or less, the light transmittance increases and the light diffusion effect cannot be sufficiently exhibited. On the other hand, 0.5
If it is more than μm, the light shielding effect is increased and the light diffusion effect is undesirably reduced. The average particle size is measured by a method such as an electron microscope, a sedimentation method, and a transmission method.

The titanium oxide is used in an amount of 0.05 to 5.0 parts based on 100 parts by weight of the thermoplastic polyester resin. If the amount is less than 0.05 part, a sufficient light diffusion effect is not exhibited. On the other hand, when the amount is more than 5.0 parts, the light shielding effect is exhibited, but the light diffusion effect is undesirably reduced. In particular, in the present invention, calcium carbonate and titanium oxide are used together, and by utilizing the characteristics of each additive, the light transmitted therethrough becomes a soft light, which is most suitable as a shade or cover of a lighting fixture. It is intended to provide a resin composition.

That is, the light diffusion effect and the milky white effect of calcium carbonate, and the light shielding effect and the light diffusion effect of titanium oxide are not limited by the numerical values (use amount and particle size) in the present invention. A remarkable synergistic effect is exhibited as compared to the case where calcium or titanium oxide is used alone. Also, at this time, if a small amount of a fluorescent whitening agent is added,
The resin composition for molding a lighting fixture of the present invention is preferable because a pale color tone is added when a lighting fixture is molded and soft light rays are remarkably emphasized, so that the milky white effect of the present invention is further enhanced.

Examples of the fluorescent whitening agent to be used include naphthalene derivatives, naphthalimide derivative compounds and bisbenzooxazolyl derivative compounds which have been conventionally compounded when kneading a thermoplastic polyester resin. In particular
CI Fluorescent Brightner367, CI Fluorescent Br
ightner 184, CI Fluorescent Brightner 398, CI
Fluorescent Brightner 52, CI Fluorescent Brightn
er 91, CI Fluorescent Brightner 258, CI Fluore
Use scent Brightner 219 alone or in combination.

The amount of the fluorescent whitening agent to be used at this time is sufficiently small to be sufficient to exhibit the above effects, but is preferably 0.001 to 0.1 part. If the amount is less than 0.001 part, a sufficient whitening effect is not exhibited, and if the amount is more than 0.1 part, the whitening effect is not so much improved. Particularly preferred fluorescent whitening agents include CI Fluorescent Brightn
er 184 and CI Fluorescent Brightner 219. Also, in the present invention, by adding ethylene ethyl acrylate (hereinafter referred to as EEA), no trouble occurs even if the lighting equipment using the extruder or the vacuum molding machine is operated for a long time. It provides stable molding and provides molding materials with excellent production efficiency.

The ethylene ethyl acrylate (hereinafter abbreviated as EEA) used as an additive in the present invention is a copolymer of ethylene and ethyl acrylate. When EEA is blended in the production of the resin composition for molding a lighting fixture of the present invention, in the production of a sheet as an intermediate product of the lighting fixture, the shape of the sheet obtained even after continuous operation for a long time is completely reduced. There is no change and the thickness of the molded product is constant. EEA is used in an amount of 0.01 to 1.0 part based on 100 parts of the thermoplastic polyester resin. If the amount of EEA used is less than 0.01 part, the above effects due to EEA blending are not exhibited, which is not preferable. Also, 3.
If the amount is more than 0 part, a cause of deterioration of mechanical properties is caused, so that 0.01 to 1.0 part is sufficient.

Thus, in the present invention, by adding EEA, even if the sheet-like molded article is manufactured for a long period of time using the resin composition for molding a lighting fixture of the present invention, troubles may occur. It greatly contributes to the improvement of production efficiency. For example, when manufacturing covers and shades for lighting fixtures using a general-purpose vacuum forming machine, even if they are operated continuously for a long time (100 to 200 hours),
All products keep the same shape, and are uniform without thickness variations. Thus, the resin composition for molding a lighting fixture of the present invention,
It can be continuously molded for a long time at the same speed as molding by using a thermoplastic polyester resin containing no additive.

The resin composition for molding a lighting fixture of the present invention can be easily obtained by mixing and kneading by a conventional method using a conventionally used mixer and extruder. At this time, even if a pigment, a dye, or a dispersant (for example, an ester wax) is arbitrarily added as needed, the excellent effect of the present invention, that is, a frosted glass effect, is not lost at all. In the production of the resin composition for molding a lighting fixture of the present invention, an ultraviolet absorber, an antioxidant, a light stabilizer, a pigment, a lubricant and the like may be added as necessary.

Examples and comparative examples will be described below. Example 1 3.0 parts of calcium carbonate having an average particle size of 1.5 μm and an average particle size of 0.
0.40 parts of 11 μm titanium oxide is uniformly mixed with a Henschel mixer. 6.0 parts of the above mixture and 100 parts of polyethylene terephthalate (intrinsic viscosity: 1.25) were mixed in a twin-screw extruder for 270 parts.
The resin composition pellets for molding a lighting fixture of the present invention are produced by melting and kneading at a temperature of ℃.

The obtained product of the present invention is sealed using an extruder.
After manufacturing the cover, a cover for 45w fluorescent lamp is
Is continuously molded, and the following (a), (b) and (c) are measured, and the results are

[Table 1] It describes in. The resin compositions for molding lighting fixtures of the present invention obtained in Examples 2 to 4 and the resin compositions obtained in Comparative Examples 1 to 10 were also manufactured by using extruders to form sheets. A hood for a lighting fixture was molded using a molding machine, and the same measurement as in Example 1 was performed.

It is described in Table 1.

(A) Light diffusing property When a 40 W fluorescent lamp cover molded using a vacuum molding machine is irradiated with light from the inner surface, the light is diffused and the outline of the fluorescent lamp is not distinguished from the outer surface of the cover. -Visually determine whether the whole is uniformly bright. A: Light diffusion is sufficiently performed, and the outline of the fluorescent lamp is not visible at all from the outer surface of the cover. ：: Although the light diffusion is considerable, the outline of the fluorescent lamp is slightly visible from the outer surface of the cover. Δ: Almost no light diffusion was observed, and the outline of the fluorescent lamp was visible from the outer surface of the cover.

(B) Milky Whiteness When a 40 W fluorescent lamp cover molded using a vacuum molding machine is irradiated with light, when the light is viewed from the outside through the cover, the entire cover is milky white and bright and softly wrapped. It is visually determined whether or not it has been lost. A: When viewed from the outer surface of the cover, the entire cover is milky white and is wrapped in bright and soft light rays.

：: When viewed from the outer surface of the cover, the entire cover is wrapped in milky light, but the light of the fluorescent lamp is somewhat shielded. Δ: When viewed from the outer surface of the cover, the light of the fluorescent lamp is considerably shielded, and the entire cover is dim. (C) Continuous operability Regarding the resin composition for molding a lighting fixture of the present invention containing EEA,
Using an extruder, a vacuum molding cover for fluorescent lamp covers
When sheets are continuously produced for 100 hours, the sheets obtained are inspected for variations in shape stability and thickness uniformity, and the continuous operability is determined from the results.

A: No variation is observed in the sheet, and continuous operation is possible for a long time. ：: The sheet may slightly vary, and there is some concern about continuous operation for a long time. Δ: The sheet greatly varies, and it is difficult to continuously operate for a long time.

[0026]

[Table 1]

Example 2 3.0 parts of calcium carbonate having an average particle size of 1.5 μm and an average particle size of 0.11
0.40 part of μm titanium oxide and 0.5 part of EEA (a product of Mitsui DuPont Chemical Co., Ltd.) are uniformly mixed with a Henschel mixer. 6.0 parts of the above mixture and 100 parts of polyethylene terephthalate (intrinsic viscosity: 1.25) were mixed in a twin-screw extruder for 270 parts.
The resin composition pellets for molding a lighting fixture of the present invention are produced by melting and kneading at a temperature of ℃. Thereafter, the same operation as in the first embodiment is performed.

Example 3 3.0 parts of calcium carbonate having an average particle size of 5 μm and an average particle size of 0.11 μm
0.40 parts of titanium oxide and a fluorescent whitening agent (CI Fluoresce
nt Brightner 184: Ciba Geigy, Inc. Ubitex O
B) Mix 0.05 parts uniformly with a Henschel mixer.
3.5 parts of the above mixture and 100 parts of polyethylene terephthalate (intrinsic viscosity 0.75) are melt-kneaded at 270 ° C. using a twin-screw extruder to produce a resin composition pellet for molding a lighting fixture of the present invention. Thereafter, the same operation as in the first embodiment is performed.

Example 4 3.0 parts of calcium carbonate having an average particle size of 5 μm and an average particle size of 0.11 μm
m titanium oxide 0.04 part, EEA (Mitsui-Dupont Chemical Co., Ltd. product) 0.5 part and optical brightener (CI Fluorescen)
t Brightner 184) Mix 0.05 parts uniformly with a Henschel mixer. 3.5 parts of the above mixture and 100 parts of polyethylene terephthalate (intrinsic viscosity 0.75) were mixed in a twin-screw extruder for 270 parts.
The resin composition pellets for molding a lighting fixture of the present invention are produced by melting and kneading at a temperature of ℃.

Thereafter, the same operation as in Example 1 is performed for the comparative example. Comparative Examples 1 to 10 The blending amounts and average particle diameters of calcium carbonate and titanium oxide in Example 2 were as follows:

[Table 2] Light diffusion, light opacification, and EEA
The continuous operability of the present invention is compared with the effect of the present invention in the second embodiment.

[0031]

[Table 2]

[0032]

According to the resin composition for molding a lighting fixture of the present invention, when a cover or shade of a lighting fixture is manufactured using the resin composition, an excellent light diffusing effect and a milky white color not seen in the conventional resin molded product can be obtained. A translucent molded product with rich design can be obtained. In particular, the resin composition of the present invention containing a fluorescent whitening agent is preferable because it gives a high-grade appearance to a product obtained by molding a cover or shade of a lighting fixture.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 33:08)

Claims (4)

[Claims] 1. Fine powder of calcium carbonate having an average particle size of 0.5 to 10 μm with respect to 100 parts by weight of a thermoplastic polyester resin.
A resin composition for molding lighting fixtures, comprising 0.05 to 5.0 parts by weight and 0.05 to 0.5 part by weight of fine titanium oxide particles having an average particle size of 0.02 to 0.5 μm. 2. An ethylene ethyl acrylate according to claim 1.
A resin composition for molding a lighting fixture, comprising 0.01 to 1.0 parts by weight. 3. A resin composition for molding a lighting fixture, comprising the fluorescent whitening agent according to claim 1. 4. An ethylene ethyl acrylate according to claim 3.
A resin composition for molding a lighting fixture, comprising 0.01 to 1.0 parts by weight.