JPH05171130A - Ultraviolet-screening transparent resin molding - Google Patents

Abstract

PURPOSE:To provide the subject transparent resin molding excellent in transparency, ultraviolet shielding properties and durability. CONSTITUTION:In a transparent resin such as polycarbonate, polyvinyl chloride or an acrylic resin, 0.5 to 10vol.% zinc oxide fine powder having <=0.1mum particle size is uniformly monodispersed and the resultant mixture is pelletized. The obtained pellet is molded into a desired shape such as a plate shape by extrusion molding, injection molding, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used in various applications such as transparent plates for show windows and showcases, transparent shades for lighting, transparent sheets for packaging foods, films, containers, etc., which require transparency and UV blocking performance. The present invention relates to a UV-blocking transparent resin molded product.

[0002]

2. Description of the Related Art It is generally known that an object is deteriorated, altered or discolored by ultraviolet rays contained in illumination light or sunlight. For example, in the case of a show window or a showcase, this ultraviolet ray is used for a transparent plate or an internal display product forming the same, for lighting, an illumination shade or an object to which illumination light is irradiated, and for transparently packaged food, a transparent packaging material or Deteriorate, deteriorate, and discolor foods,
Adversely affect.

Conventionally, in order to prevent the adverse effects of ultraviolet rays, the transparent plate, the transparent shade, the transparent packaging material, and other various transparent bodies are coated with an organic ultraviolet absorber or titanium oxide on the surface thereof. Alternatively, a coating material containing zinc oxide was applied to form an ultraviolet blocking coating film.

[0004]

However, when a coating material containing an organic ultraviolet absorber is applied, benzophenone type, benzotriazole type, salicylate type,
Organic UV absorbers such as substituted acrylonitrile-based have a problem in hygiene to human body and have poor heat resistance.
As the coating film absorbs ultraviolet rays, the coating film itself tends to deteriorate and discolor.

When a coating material containing titanium oxide is applied, there is a problem that the titanium oxide itself turns yellow due to ultraviolet rays. When a coating material containing zinc oxide is applied, a transparent coating film superior to the above two coating films can be obtained, but since zinc oxide fine particles are distributed on the surface, zinc oxide may be affected by moisture in the air, etc. There is a problem that it is easily deteriorated to zinc hydroxide and inferior in durability.

Further, in all the conventional ones, a coating material is applied to the surface of the transparent body to form an ultraviolet blocking coating film.
For example, in a show window, a showcase, etc., in order to protect both the transparent body that forms them and the products displayed inside from ultraviolet rays, it is necessary to apply paint to both the inside and outside of the transparent body, which is a troublesome application work. Along with that, the cost was high.

An object of the present invention is to provide an ultraviolet-blocking transparent resin molded body that solves the above conventional problems.

[0008]

In order to solve the above problems, the present invention focuses on ultrafine zinc oxide particles which are harmless to the human body, are hard to discolor by ultraviolet rays, and have transparency. That is, the ultraviolet blocking transparent resin molded product of the present invention is one in which fine zinc oxide powder having a particle size of 0.1 μm or less is uniformly monodispersed in a transparent resin in an amount of 0.5 to 10% by volume.

[0009]

The present invention will be described below. The ultraviolet blocking transparent resin molded product of the present invention has a desired shape such as a plate-like shape obtained by extrusion molding, injection molding or the like after uniformly finely dispersing zinc oxide fine powder having a particle diameter of 0.1 μm in a transparent resin to form pellets. It is a molded product. As the transparent resin, polycarbonate, polyvinyl chloride, acrylic resin or the like is used. As a method for dispersing the zinc oxide fine powder in the resin, a conventional method may be appropriately adopted.

The zinc oxide fine powder is preferably ultrafine particles having a particle size of 0.1 μm or less so that the transparency of the transparent resin molding is not impaired and the ultraviolet ray blocking performance is exhibited. Also, zinc oxide fine powder is generally contained in a transparent resin at 0.5
It is preferably uniformly monodispersed in an amount of 10% by volume. The reason is that the UV blocking performance cannot be exhibited at 0.5% by volume or less, and 1
This is because if it is 0% by volume or more, it cannot be uniformly monodispersed in the transparent resin. More preferably, the zinc oxide fine powder content is in the range of 0.5 to 2% by volume.

Next, a zinc oxide fine powder having a particle diameter of 0.1 μm or less is uniformly dispersed in acrylic resin in an amount of 2% by volume and pelletized, and the pellet is extruded to form a plate having a thickness of 2 mm. Example) and a transparent plate (comparative example) in which a conventional paint containing zinc oxide was applied to both sides of an acrylic plate having a thickness of 2 mm to form a coating film (Comparative Example), and the ultraviolet cut rate and visible light transmittance were examined. Is shown below.

The ultraviolet cut rate and the visible light transmittance were measured by using a spectrophotometer UV-1200 manufactured by Shimadzu Corporation in the initial state of the transparent plate and the state after the weather resistance test (500 hours) by a sunshine weather meter.

Initial state State after weathering test UV cut rate Visible light transmittance UV cut rate Visible light transmittance Example 100% 88% 90% 85% Comparative example 98% 90% 82% 78%

Although the initial performances of the examples and the comparative examples were almost the same, it was confirmed that the examples were superior to the comparative examples in the performance in the state after the weather resistance test.

[0015]

As described above in detail, in the ultraviolet blocking transparent resin molding of the present invention, zinc oxide fine powder having a particle size of 0.1 μm or less is uniformly dispersed in the transparent resin in an amount of 0.5 to 10% by volume. Therefore, without impairing the transparency of the molded body, it can exhibit excellent ultraviolet blocking performance, and it does not easily discolor or deteriorate due to ultraviolet rays like conventional ultraviolet blocking coatings with paint,
A stable transparent body can be obtained.

Moreover, since the zinc oxide fine powder is dispersed inside the transparent resin molded body, zinc oxide is distributed on the surface of the transparent body as in the case of the conventional UV-shielding coating film prepared by the zinc oxide-blended coating composition. It is difficult for the moisture to change into zinc hydroxide, and the deterioration of zinc oxide can be delayed as much as possible to improve the durability.

Further, since the zinc oxide fine powder is a monodispersed product uniformly dispersed in a transparent resin, it is troublesome to apply a coating material to both the inner and outer surfaces of the transparent body to prevent ultraviolet deterioration as in the prior art. The molded article itself has UV blocking performance,
It can be cheaper in terms of cost.

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Claims (1)

[Claims] 1. An ultraviolet-blocking transparent resin molded product obtained by uniformly dispersing 0.5 to 10% by volume of zinc oxide fine powder having a particle size of 0.1 μm or less in a transparent resin.