JP2008036849A - Thermoplastic resin composite sheet - Google Patents

Abstract

A heat having a high-quality appearance that can prevent insects from gathering in response to light from a light source such as a fluorescent lamp, and reduces the presence of a lamp without any sense of incongruity even when the light source is turned off. Provision of a plastic resin composite sheet and a method for producing the same.
A core layer made of a thermoplastic resin containing an ultraviolet absorber, and a heat content of the ultraviolet absorber formed on both surfaces of the core layer is smaller than the content of the ultraviolet absorber in the core layer. A thermoplastic resin composite sheet comprising a skin layer made of a plastic resin.
[Selection figure] None

Description

  The present invention relates to a rational manufacturing technique of a thermoplastic resin sheet containing a relatively large amount of an ultraviolet absorber, and a high-quality lighting cover member that can prevent the attraction of insects when a fluorescent lamp is turned on.

Household and facility lighting as an example using a resin light source protective cover that sufficiently transmits light from a light source such as a fluorescent lamp and uniformly diffuses to prevent the light source from directly touching the viewer's eyes And various displays such as food and clothing, display signs, and the like.
On the other hand, it is well known that insects have a tendency to fly against light stimuli, and they often gather when the light source is turned on, which has an adverse effect on aesthetics and hygiene. .

Insects are particularly sensitive to wavelengths close to the ultraviolet region, and therefore, many measures have been devised to cover light sources and substantially block light with wavelengths below 380 nm. Some insects are active in response to wavelengths longer than 380 nm, which is the visible light region. The transmittance of light with a wavelength of 400 to 480 nm is 30% or less, and the transmittance of light with a wavelength of 580 nm or more is substantially blocked. A technique of an insect repellent method using a resin sheet characterized by not being used as a partition material is disclosed (Patent Document 1).
Also disclosed is an acrylic resin transparent film that cuts light of a wavelength of 400 nm or less and has a high transmittance of light of 420 nm or more, and a technology for a resin laminate for a lighting cover, characterized by having this on the surface. (Patent Document 2).

  Furthermore, in order to reduce the light transmittance in the wavelength range of 410 nm or less to 1% or less for the purpose of more effectively preventing insects' sensitivity, the maximum absorption wavelength is less than 350 nm due to the ultraviolet absorption characteristics of the ultraviolet absorber. Needs to be contained in a large amount, and even when a material having a maximum absorption wavelength of 350 to 370 nm that absorbs up to a long wavelength region is selected, a relatively large amount of addition is required, and an acrylic resin composition having a thickness of 2 mm It is exemplified that an amount exceeding 1% by weight, which is considerably larger than the amount added to protect the acrylic resin normally carried out on a sheet from ultraviolet deterioration, is necessary (Patent Document 3).

As a method for producing a resin sheet for a light source protective cover, there is an extrusion molding method using a thermoplastic resin as a raw material, which can be continuously produced, and is widely practiced because of its uniform thickness and high surface accuracy.
In this case, it is necessary to plasticize and extrude the thermoplastic resin at a high temperature range of about 230 ° C. or higher. When the amount of the ultraviolet absorber is large, the ultraviolet absorber is bleed out (volatilized), volatilized, sublimated, etc. There is a problem that it adheres to the equipment and deteriorates the quality of the product obtained.
In particular, during sheet extrusion, the UV absorber accumulates during continuous operation on the surface of the T-die outlet and the polishing roll, which is an important device for determining the appearance quality of the obtained sheet surface. In order to eliminate this defect, it is necessary to stop the operation because it is necessary to clean and polish the equipment, and the continuous and stable operation is hindered.

In addition, if a large amount of ultraviolet absorber is added to cut light of 410 nm or less, the resin sheet tends to have a yellow color. If this is used as a cover member, the color tone of the original light source may be impaired when the fluorescent lamp is turned on. In addition, it becomes difficult to obtain a preferable transparent or white state when the fluorescent lamp is turned off.
In particular, there is a need for a lighting cover member that has a refreshing transparent or white high-quality appearance when it is turned off in the room, and that is well harmonized with the surroundings and weak in its presence. In general, the member gives an image that is old or deteriorated, and therefore, there is a problem that this request cannot be met.

JP-A-62-278931 JP 2000-169767 A JP 2005-58019 A

  The present invention can prevent insects from gathering in response to light from a light source such as a fluorescent lamp, and has a high-grade appearance that reduces the presence of the lamp without any sense of incongruity even when the light source is turned off. It is an object of the present invention to provide a technique that enables stable and continuous production of a thermoplastic resin composite sheet.

In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that a thermoplastic resin composite sheet having the following configuration and a method for producing a thermoplastic resin composite sheet solve the above problems.
(1) A core layer made of a thermoplastic resin containing an ultraviolet absorber, and a thermoplastic resin formed on both surfaces of the core layer, the ultraviolet absorber content rate being less than the ultraviolet absorber content rate in the core layer A thermoplastic resin composite sheet comprising a skin layer made of a resin.
(2) The core layer has a UV absorber content of 0.1 to 3.0% by weight and a thickness of 0.5 to 5 mm, and the skin layer has a UV absorber content of 0. The thermoplastic resin composite sheet according to (1), which is less than 1% by weight and has a thickness of 10 to 200 μm.
(3) The thermoplastic resin composite sheet according to (1) or (2), wherein the total light transmittance is 80% or more.
(4) The thermoplastic resin composite sheet according to (1) or (2), wherein the total light transmittance is 30 to 80%.
(5) The thermoplastic resin composite sheet according to any one of (1) to (4), wherein the skin layer contains a matting agent.
(6) The thermoplastic resin according to any one of (1) to (5), wherein the thermoplastic resin is at least one selected from PMMA resins, MS resins, and PC resins. Composite sheet.
(7) An illumination cover for low worms comprising the thermoplastic resin composite sheet according to any one of (1) to (6).
(8) Thermoplastic resin having a core layer made of a thermoplastic resin containing an ultraviolet absorber and a content ratio of the ultraviolet absorber formed on both surfaces of the core layer smaller than the content ratio of the ultraviolet absorber in the core layer A method for producing a thermoplastic resin composite sheet, comprising coextruding a skin layer comprising

  According to the present invention, insects can be prevented from crowding in response to light from a light source such as a fluorescent lamp, and can be transmitted without greatly impairing the color tone of the light from the light source. Disclosed is a useful technique that enables a stable and stable production of a thermoplastic resin composite sheet having a high-quality appearance that diffuses and reduces the presence of a lamp without discomfort when the light source is turned off.

The present invention will be described in detail below.
The thermoplastic resin composite sheet of the present invention is prepared by using a thermoplastic resin as a raw material, and coating a skin layer containing an ultraviolet absorber on both surfaces of a core layer containing an ultraviolet absorber at a content ratio lower than that in the core layer. It consists of a multilayer sheet obtained by extrusion molding. Preferably, the content of the ultraviolet absorber is 0.1 to 3.0% by weight of the core layer and less than 0.1% by weight of the skin layer, more preferably the core layer. It is 1.0 to 3.0% by weight, and the skin layer is less than 0.05% by weight. In some cases, the skin layer may be substantially free of an ultraviolet absorber.

About the kind of thermoplastic resin used by this invention, PMMA (acrylic) type, PS (polystyrene) type, MS (copolymer of acrylic and styrene) type, PC (polycarbonate) type, PVC (vinyl chloride) type, etc. Is mentioned.
Among these, when used as a lighting cover for low insects, PMMA and MS systems that have high transparency, sufficient mechanical strength and durability, and excellent coextruded sheets with excellent surface workability are obtained. The PC system is recommended as a suitable material, and the combination of the resin for the core layer and the skin layer may be the same or different as long as the core layer and the skin layer are in close contact with each other.
The sheet layer structure may be a combination of two types and three layers in which the resin and composition of the skin layer are the same, or a combination of three types and three layers in which the resin and composition of the skin layer are different on the front and back sides.

The PMMA resin that can be used in the present invention is a resin mainly composed of methyl methacrylate, and may be a homopolymer of methyl methacrylate, or methyl methacrylate and methyl acrylate, ethyl acrylate, butyl acrylate, within a range of 30% by weight or less. It may be a copolymer with at least one copolymerizable monomer such as acrylonitrile, acrylic acid, methacrylic acid, 2-hydroxyacrylate, maleic anhydride, and α-methylstyrene. These may be used alone or in a blend.
In order to maintain transparency and have impact resistance at the same time, an elastic layer mainly composed of butyl acrylate and an inelastic layer mainly composed of methyl methacrylate are alternately arranged around the methacrylic polymer core material. An impact-resistant methacrylic resin blended with a methacrylic rubber elastic body composed of a multistage polymer produced by a multistage sequential polymerization method is also included in the PMMA resin of the present invention.

The MS-based resin that can be used in the present invention is a resin mainly composed of a copolymer of methyl methacrylate and styrene, but any one or more of the copolymerizable monomers as exemplified in the PMMA-based resin as a whole. A multi-component copolymer added in an amount of 30% by weight or less is also included, and these may be used alone or blended.
When the total amount of the MS resin is 100 parts, it is more preferable that the ratio of methyl methacrylate exceeds 60 parts because of good light resistance.
In order to improve the impact strength of MS resin, multi-stage sequential generation of alternating elastic layer mainly composed of butyl acrylate and inelastic layer mainly composed of methyl methacrylate around acrylic polymer core material A rubber elastic body produced by a polymerization method or a butadiene rubber elastic body blended with an MS resin is also included in the MS resin of the present invention.

  Examples of the PC resin include aromatic polycarbonates typified by the bisphenol A type, and aromatic-aliphatic polycarbonates having an aromatic ring but having no hydroxyl group directly bonded to the aromatic ring.

The thermoplastic resin is most preferably a PMMA resin because it has the highest transparency and durability.
These resins may contain other components such as light diffusing agents, bluing agents, fluorescent whitening agents, coloring pigments, coloring dyes, heat stabilizers, antioxidants, and light stabilizers as long as the properties are not impaired. Etc. can be contained.

Examples of the light diffusing agent include general-purpose inorganic light diffusing agents such as fine powdered barium sulfate, calcium carbonate, titanium oxide, etc., and acrylic resin-based, styrene-based, silicone-based crosslinked transparent resin powders, etc. as organic types Particles are also well known.
The average particle diameter of the light diffusing agent used in the present invention is preferably from 0.1 to 50 μm, and the visible light is effectively refracted and reflected at the interface of each particle in the transparent resin, so that light transmittance and light diffusibility are achieved. It is preferable at the point from which the outstanding lighting cover for low insects is obtained.
These light diffusing agents may be mixed and used.

Furthermore, it is also possible to adjust the color tone by containing a known bluing agent.
As this bluing agent, an anthraquinone derivative C.I. I. Solvent Blue 94 (manufactured by Mitsubishi Chemical Corporation, trade name Diaresin Blue N) is preferred.
Further, when a known fluorescent whitening agent is contained in the transparent resin, it is recommended in that the color tone is further stabilized by the combined use effect with the light diffusing agent particles, and the original color tone is expressed with various light sources.

When used for a low moth-lighting illumination cover, the core layer thickness is preferably in the range of 0.5 to 5 mm, and the strength of the sheet is high at 0.5 mm or more, and is easy to attach at 5 mm or less.
It is important to provide a skin layer according to the constitution of the present invention, and the skin layer can prevent bleeding out, volatilization and sublimation of the UV absorber contained in the core layer. In addition, unevenness can be eliminated, and furthermore, printing defects and stickiness due to bleed-out due to aging of the obtained product can be prevented.

In addition, because the skin layer is formed, the sheet appearance has a deep and high-class feeling, and the color tone can be finely adjusted, and if a matting agent is blended, it can impart surface matting properties. In addition, it is advantageous in that it can be highly functionalized without significantly changing the original physical performance of the sheet by providing other functions such as antistatic properties and antifogging properties.
Examples of the matting agent include organic polymer fine particles such as PMMA and PS having a crosslinked structure, and inorganic fine particles such as talc and mica.

  The thickness of the skin layer is recommended to be in the range of 10 to 200 μm, and within this range, the characteristics of the sheet for the light source protective cover are maintained depending on the optical characteristics and color tone of the core layer, and a wide variety of low thicknesses are not constrained by the layer structure. Although the design of the lighting cover for insects becomes possible, when it is 10 μm or more, it becomes a uniform thickness at the time of co-extrusion, and when it is 200 μm or less, the performance of the core layer is preferably maintained.

The thermoplastic resin composite sheet of the present invention is cut into a predetermined size, and if necessary, is secondarily processed into a three-dimensional shape and a curved surface by a thermoforming method such as vacuum forming or pressure forming, as a lighting cover for low worms. Can be used.
Furthermore, a low worming illumination cover having a simple three-dimensional shape and curved surface can be continuously obtained even by the method of profile coextrusion molding using a profile die.

  The thermoplastic resin composite sheet of the present invention is obtained by coextrusion molding. To make a multilayer sheet by coextrusion molding, a main extruder for extruding the core layer and a sub-extruder for extruding the skin layer are provided, and a sheeting line composed of a T die, a polishing roll, a take-up roll, etc. Based on the sheet shaping method that uses, generally, a multi-manifold system in which a feed block is installed between each extruder and a T-die and a multi-layer structure in which a multi-layer structure is directly formed in the die is well known. ing.

The thermoplastic resin composite sheet of the present invention preferably has a total light transmittance in the thickness direction of 80% or more, more preferably 85% or more as measured by JIS-K7361-1, when the thickness is 3 mm. .
Moreover, in order to add a light diffusing agent and maintain a sufficient balance between light transmittance and light diffusibility, the total light transmittance measured by the same method is preferably in the range of 30 to 80%, 40 to Those in the range of 80% are more preferable.
Further, in the thermoplastic resin composite sheet of the present invention, in order to prevent the attraction of insects, the transmittance at an ultraviolet wavelength of 400 nm or less is preferably 20% or less, and more preferably 10% or less.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
In addition, the evaluation and test method used by each Example and the comparative example are as follows.
(1) Appearance: The obtained extruded sheet is visually observed, and “O” indicates no abnormality on the surface, and “X” indicates abnormality such as cloudiness and uneven gloss on the surface.
(2) Total light transmittance: Measured according to JIS K7361-1 using an NDH2000 type turbidimeter manufactured by Nippon Denshoku Industries Co., Ltd.
(3) Spectral light transmittance: Measured using a UV-3150 spectrophotometer manufactured by Shimadzu Corporation, and the transmittance curve is recorded on a chart.

[Examples 1-7]
The core layer raw material for the light source protective cover resin sheet was prepared in the proportions shown in Table 1, with a PMMA resin (manufactured by Asahi Kasei Chemicals Co., Ltd., trade name Delpowder 70H) and 2- [ 5-Chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (Ciba Specialty Chemicals Co., Ltd., trade name TINUVIN 326), and if necessary, light diffusion After mixing the agent and mixing homogeneously using a tumbler, it was melt-kneaded at a resin temperature of 250 ° C. with a vented 30 mmφ twin-screw extruder and pelletized to obtain core layer materials A1 to A3.
The light diffusing agent a is heavy calcium carbonate manufactured by Dowa Calfine Co., Ltd., and is trade name Ace 25 (average particle size 1.5 μm). Similarly, the light diffusing agent b is settling property manufactured by Nippon Chemical Industry Co., Ltd. Barium sulfate is trade name AD (average particle size 3 μm).

The material for the skin layer of the resin sheet for the light source protective cover was prepared by mixing PMMA resin (manufactured by Asahi Kasei Chemicals Co., Ltd., trade name Delpowder 70H) and ultraviolet absorber 2 (2- (2H -Benzotriazol-2-yl) -P-Cresol Ciba Specialty Chemicals Co., Ltd., trade name: TINUVIN P / Absorbs light in the ultraviolet region that causes resin deterioration, yellowing of the resin, and deterioration of mechanical properties Etc.), and other ingredients are blended if necessary, mixed homogeneously using a tumbler, and then melt-kneaded at a resin temperature of 250 ° C. with a vented 30 mmφ twin screw extruder to give pellets The skin layer materials B1 to B3 were obtained.
The other component c is a surface matting agent, which is a product name talc NTX-174A (MSP) manufactured by Nippon Talc Co., Ltd., d is an antistatic agent, manufactured by Takemoto Yushi Co., Ltd., which is mainly composed of sodium alkanesulfonate. Product name AKS-540 is shown, e is a heat stabilizer, and shows the product name Adeka Stub AO-412S made by Asahi Denka Kogyo Co., Ltd. of organic sulfur type.

The feed block is connected to the main extruder for the core (screw diameter 50 mmφ, L / D = 32, single shaft) and the sub-extruder for the skin (screw diameter 32 mmφ, L / D = 32, single shaft). Two-type three-layer sheet molding was carried out by a co-extrusion method by a conventional method using a die and a unit consisting of three glazing rolls and a take-up roll.
Core layer materials A1 to A3 were used for the main extruder, and skin layer materials B1 to B3 were used for the sub-extruder.
The resin temperature at the time of sheet extrusion was set to 260 ° C., and the obtained sheet had a structure in which skin layers were laminated on both sides of the core layer, and the thickness of each layer was adjusted by the balance of extrusion amounts of the main and sub extruders.
Adjust the distance between the T-die discharge port and the polishing roll, and the rotational speed of the polishing roll and take-up roll. The overall thickness of the sheet is set to 2.0 mm, the sheet extrusion speed is 1.2 m / min, and the width A 240 mm coextruded sheet was obtained.

In the sheets of Examples 1 to 5 thus obtained, a skin layer having a thickness of 50 μm was formed on each of both surfaces of the core layer.
In Examples 6 and 7, the rotation speed of the take-up roll was changed to a faster direction sequentially.
In Example 6, a coextruded sheet having a width of 225 mm was obtained at a sheet extrusion speed of 1.6 m / min. This sheet had an overall thickness of 1.5 mm, and a skin layer having a thickness of 40 μm was formed on each side of the core layer.
In Example 7, a coextruded sheet having a width of 215 mm was obtained at a sheet extrusion speed of 2.4 m / min. This sheet had a total thickness of 1.0 mm, and a skin layer having a thickness of 30 μm on each side of the core layer.

Table 3 summarizes the combinations of the core layer raw material and the skin layer raw material used, and the evaluation results of the obtained sheet. Moreover, the spectral-light transmittance chart of the sheet | seat obtained in Examples 1-7 is shown in FIGS.
Each of the obtained sheets has a good appearance and is a resin sheet suitable for a lighting cover.
In addition, from the spectral light transmittance chart, the sheets of Examples 1 to 7 hardly transmit light of 410 nm or less, and transmit or diffuse light in the visible light region well to attract insects when the fluorescent lamp is turned on. It turns out that it has the performance as a preferable illumination cover, having the function to prevent.

In addition to this, in Examples 2-7, the surface of the sheet exhibits a matte mat state because talc (other component c), which is a matting agent, is blended in the skin layer. When the 60 ° glossiness of the surface is measured using a gloss checker IG-331 manufactured by HORIBA, Ltd., all the sheets are in the range of 15 ± 3, and the texture is less reflected by surface reflection of external light. It is an excellent lighting cover sheet.
Among these, the sheet color tone of Example 4 has the highest whiteness by visual observation and is preferable.
Furthermore, in Examples 4-7, in addition to the matte mat, it also has antistatic performance, and the surface resistance value measured using the super insulation meter SM-8200 and the electrode SME-8301 manufactured by Toa DKK Corporation is 10 × 10 power. This is the following, which indicates that the lighting cover is excellent with little electrification and less dust adhesion due to static electricity.

[Examples 8 and 9]
MS resin (Estyrene MS600, Transparent / Nippon Chemical Co., Ltd.) was used as the thermoplastic resin, the blending ratios shown in Table 1 were used, and the resin temperature at the time of extrusion was set to 230 ° C., as in Example 1. Thus, core layer raw material A4 was obtained.
Moreover, MS-type resin (Estyrene MS600, transparent / Nippon Steel Chemical Co., Ltd. product) was used, it was made into the mixture ratio shown in Table 2, and the resin temperature at the time of extrusion was set to 230 degreeC, and it carried out similarly to Examples 1-7. Skin layer material B4 was obtained.
Core layer material A4 is used for the main extruder, and skin layer material B4 (Example 8) or skin layer material B3 (Example 9) is used for the sub-extruder, and the resin temperature during sheet extrusion is set to 240 ° C. A coextruded sheet was obtained in the same manner as in Example 1.
The obtained evaluation results are collectively shown in Table 3. All have good appearance and are resin sheets suitable for lighting covers.
In addition, from the spectral light transmittance charts of the sheets of Examples 8 and 9 shown in FIGS. 8 and 9, insects hardly transmit light of 410 nm or less, transmit light in the visible light region well, and turn on the fluorescent lamp. It can be seen that it has a preferable performance as a lighting cover while having a function of preventing the attraction of the light.
Moreover, the sheet | seat of Example 9 is exhibiting the mat | matte mat state on the surface of the sheet | seat from the talc (other component c) which is a matting agent being mix | blended with the skin layer like the sheet | seat of Examples 2-7. In addition to being an illumination cover sheet having a surface glossiness of 13 and an excellent texture with little reflection due to surface reflection of external light, it contains an antistatic agent in the same manner as the sheets of Examples 4-7. Therefore, the surface resistance value is 10 × 10 or less, and it is an excellent lighting cover with less charge and less dust adhesion due to static electricity.

[Example 10]
PC-type resin (Panlite K-1300, transparent / Teijin Chemicals Co., Ltd. product) is used as the thermoplastic resin, the mixing ratio shown in Table 1 and Table 2 is used, and the resin temperature during extrusion is adjusted to 280 ° C. In the same manner as in Example 1, core layer material A5 and skin layer material B5 were obtained.
A co-extruded sheet was obtained in the same manner as in Example 1 except that the core layer material A5 was used for the main extruder, the skin layer material B5 was used for the sub-extruder, and the resin temperature during sheet extrusion was set to 280 ° C. .
The obtained evaluation results are collectively shown in Table 3. All have good appearance and are resin sheets suitable for lighting covers.
Further, from the spectral light transmittance chart of Example 10 shown in FIG. 10, the function of preventing the attracting of insects when the fluorescent lamp is lit by hardly transmitting light of 410 nm or less and transmitting light in the visible light region well. It can be seen that it has a preferable performance as a lighting cover.

[Comparative Example 1]
As raw materials, B1 was used for the main extruder and A1 was used for the sub-extruder, and the two-type three-layer sheet was formed by the coextrusion method in the same manner as in Example 1.
When extrusion was started, fogging began to occur on the hard chrome plating surface of the polishing roll polished on the mirror surface, and it was confirmed that this fogging became deeper as time passed.
Uneven gloss was observed on the surface of the sheet collected after about 30 minutes, and the appearance was impaired.

[Comparative Examples 2 and 3]
Extruded sheets were prepared in the same manner as in Example 1 except that only the main extruder was used, the sub-extruder side inlet of the feed block was closed, and extrusion was performed using the core layer raw materials A1 and A3.
The obtained sheet was a single layer without a skin layer.
When extrusion was started, fogging began to occur on the hard chrome plating surface of the polishing roll polished on the mirror surface, and it was confirmed that this fogging became deeper as time passed.
Uneven gloss was observed on the surface of the sheet collected after about 30 minutes, and the appearance was impaired.

[Comparative Example 4]
Extruded sheets were prepared in the same manner as in Example 8 except that only the main extruder was used and extrusion was performed using the core layer raw material A4.
The obtained sheet was a single layer without a skin layer.
When the extrusion is started, clouding starts to occur on the hard chrome plating surface of the polishing roll polished on the mirror surface in the same manner as in Comparative Examples 1 and 2, and the phenomenon that this clouding becomes deeper as time passes is confirmed, about 30 minutes The surface of the sheet collected later had uneven gloss and the appearance was impaired.

[Comparative Example 5]
A single-layer extruded sheet having no skin layer was prepared in the same manner as in Example 10 except that only the main extruder was used and extrusion was performed using the core layer raw material A5.
When extrusion is started, fogging starts to occur on the hard chrome plating surface of the polishing roll polished on the mirror surface in the same manner as in Comparative Examples 1 to 3, and the phenomenon that this fogging becomes deeper as time passes is confirmed, about 30 minutes The surface of the sheet collected later had uneven gloss and the appearance was impaired.

[Reference example]
In Example 5, a composite sheet was obtained in the same manner as in Example 5 except that A3 containing no UV absorber 1 was used as the core layer material. A chart of the spectral light transmittance of this composite sheet is shown in FIG. As shown in FIG. 11, this composite sheet transmits light of 410 nm or less.

  INDUSTRIAL APPLICATION This invention can be utilized suitably in the field | area regarding manufacture of the resin sheet for lighting covers which prevents insect attraction.

The figure which shows the spectral light transmittance of the composite sheet obtained in Example 1 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 2 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 3 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 4 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 5 The figure which shows the spectral-light transmittance of the composite sheet obtained in Example 6 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 7 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 8 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 9 The figure which shows the spectral light transmittance of the composite sheet obtained in Example 10 Reference Example: A graph showing the spectral light transmittance of a composite sheet in which the core layer of Example 5 is not blended with an ultraviolet absorber.

Claims (8)

  A core layer made of a thermoplastic resin containing a UV absorber, and a thermoplastic resin formed on both surfaces of the core layer, the UV absorber content rate being less than the UV absorber content rate in the core layer A thermoplastic resin composite sheet comprising a skin layer.   The core layer has a UV absorber content of 0.1 to 3.0% by weight and a thickness of 0.5 to 5 mm, and the skin layer has a UV absorber content of 0.1% by weight. The thermoplastic resin composite sheet according to claim 1, wherein the thermoplastic resin composite sheet has a thickness of 10 to 200 μm.   The thermoplastic resin composite sheet according to claim 1, wherein the total light transmittance is 80% or more.   The thermoplastic resin composite sheet according to claim 1 or 2, wherein the total light transmittance is 30 to 80%.   The thermoplastic resin composite sheet according to any one of claims 1 to 4, wherein the skin layer contains a matting agent.   The thermoplastic resin composite sheet according to any one of claims 1 to 5, wherein the thermoplastic resin is at least one selected from PMMA resins, MS resins, and PC resins.   The lighting cover for low insects which consists of a thermoplastic resin composite sheet of any one of Claims 1-6.   A core layer made of a thermoplastic resin containing an ultraviolet absorbent, and a skin made of a thermoplastic resin in which the content of the ultraviolet absorbent formed on both sides of the core layer is less than the content of the ultraviolet absorbent in the core layer A method for producing a thermoplastic resin composite sheet, comprising coextruding a layer.

Images