JP2000019313A - Reflector and curved surface reflector using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to prevent the clouding of a reflection surface which occurs under elevated temp. and to obviate the degradation in the luminance of a backlight by the clouding by forming an oligomer deposition preventive layer, a polyester film and a silver thin film layer in this order and forming the oligomer deposition preventive layer side as the reflection surface. SOLUTION: This reflector is formed with the oligomer deposition preventive layer 10, the polyester film 20 and the silver thin film layer 30 in this order and is formed with the oligomer deposition preventive layer 10 side as the reflection surface. The incident light from the oligomer deposition preventive layer 10 side mostly transmits the oligomer deposition preventive layer 10 and the polyester film 20 and arrives at the silver thin film layer 30. This light is reflected by the silver thin film layer 30, is transmitted through the polyester film 20 and the oligomer deposition preventive layer 10 and is again returned to the inside of the original medium. The oligomer deposition preventive layer 10 in this reflection process prevents the deposition of the oligomer in the polyester film 20 to the reflection surface of the reflector under the elevated temp. and the occurrence of the clouding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector using silver having a high reflectance and a curved reflector using the same. More specifically, the present invention relates to a reflector excellent in heat resistance that does not cause opacity on a reflection surface even in a high temperature environment, and a curved reflector using the same. INDUSTRIAL APPLICABILITY The reflector and the curved reflector of the present invention are used for a lamp reflector of a backlight of a liquid crystal display device, a reflector used for a printer and a facsimile, a reflector for a fluorescent lamp, a reflector for a strobe, a compact mirror, and the like. . It can be used for almost all other light reflectors.

[0002]

2. Description of the Related Art Silver has a high reflectance in the visible light range and the infrared range, and has the highest electrical and thermal conductivity among metals. Therefore, silver is used as a visible light reflecting material, a heat ray reflecting material, and an electric wiring material. Attention has been paid. Generally, it does not oxidize in the atmosphere, but reacts with sulfur dioxide and sulfur in the atmosphere to produce black silver sulfide. In addition, it reacts with ozone to produce black silver oxide (AgO).

As a method for preventing silver from being sulfurized by the atmosphere, a method of alloying silver is known. For example, for electrical contacts, silver containing 3-40 wt% Cu,
Silver containing Cd and silver containing 10 wt% of Au are used. For dental use, 25 wt% Pd and 1%
Silver containing 0 wt% Cu, 5-20 wt% for decoration
Silver containing Cu is used. The practical performance of silver is described in detail in "Practical Knowledge of Precious Metals", edited by Yuzo Yamamoto, Toyo Keizai Shinposha, 1982, pp. 72-153.

As another sulfurization preventing method, there is known a method of coating silver with a metal layer or a metal oxide layer, a metal sulfide layer, an alloy layer, an undercoat resin layer, and a protective resin layer. For example, a method is known in which after silver is formed on glass, an alloy layer made of Cu and Sn is laminated, and further, a resin layer is laminated to prevent corrosion of silver and increase scratch resistance. (JP-A-49-107547). In addition, the present inventors also use a metal layer made of aluminum, titanium, or the like on both surfaces of the silver thin film layer, so that the light of the silver thin film layer
A method for preventing corrosion due to heat, gas and the like is disclosed (JP-A-1-279201).

A high-reflectance reflector using silver as a reflector is mainly used for a lamp reflector in a backlight portion of a liquid crystal display device, a reflector for a fluorescent lamp, a mirror tunnel of a minilab machine, and the like. These are so-called reflectors (silver reflectors) having a layer structure of PET (polyethylene terephthalate) / silver thin film layer / adhesive layer / aluminum plate;
This is a so-called reflection sheet (silver reflection sheet) composed of a silver thin film layer / adhesive layer / aluminum thin film layer / PET / light shielding layer.
These are to prevent the sulfurization and oxidation of silver due to exposure to the atmosphere, which was a conventional problem, by coating the silver thin film layer with a transparent polymer film PET and an adhesive layer, and to maintain high reflectance. succeeded in. For example, when the silver reflection plate and the silver reflection sheet were left in a thermostat at 80 ° C. for 1000 hours, no discoloration of black or yellow due to sulfuration or the like was observed, and the reflectance did not decrease. 60 ° C, 85%
After being left for 1000 hours in a constant temperature and humidity chamber of RH, no discoloration and no decrease in reflectance were observed.

[0006] The present inventors have developed Q-PANEL (USA).
When the above-mentioned silver reflection plate and silver reflection sheet were subjected to an ultraviolet irradiation test using a QUV tester, the result was that the reflection surface turned reddish purple. These were evident from the commonly known colors such as black, yellow-brown, and yellow due to silver sulfidation and oxidation, and were also different from yellowing due to ultraviolet degradation of the PET film itself. Therefore, the discoloration that occurs under the irradiation of ultraviolet light is called photodegradation of silver due to ultraviolet light (ultraviolet light deterioration). On the other hand, we have proposed a flexible substrate (PE) having a transmittance of light of 10% or less at a wavelength of 380 nm to 300 nm.
By laminating a metal thin film containing silver on one side of T),
A reflector having improved durability against ultraviolet light without significantly lowering the reflectance in visible light (Japanese Patent Application Laid-Open No. H5-1622).
27, US-5276600).

[0007] Further studies on the ultraviolet degradation of the transparent polymer film / silver reflector revealed that, surprisingly, they also turned reddish purple upon irradiation with visible light. Further, it was found that the photodegradation progressed very slowly at room temperature, but progressed rapidly at high temperature. Therefore, in order to distinguish the characteristics of the light deterioration from the mere light deterioration in order to further clarify the characteristics of the light deterioration, these deteriorations will be referred to as photothermal deterioration hereinafter. In contrast, we have found and disclosed that photothermal degradation can be prevented by performing a surface treatment with a plasma containing a metal on one surface of a transparent polymer film and subsequently forming a silver thin film layer on the surface-treated surface. . (JP-A-09-150482).

Liquid crystal display devices have been made thinner, lighter, have a larger screen, and have higher brightness. In response to this, backlights for liquid crystal display devices (LCDs) have higher brightness lamps and require more members. Densification is progressing. In the lamp reflector, an increase in the light intensity and an increase in the temperature are observed with the increase in the brightness of the lamp, and the increase in the density of the member further promotes the increase in the temperature. As an example of the rise in temperature, the temperature rise of a lamp reflector caused by lamp lighting was conventionally 20 to 30 ° C., but is now 30 to 50 ° C.
° C.

The use of liquid crystal display devices has been rapidly expanding in recent years. Conventionally, indoor uses such as notebook personal computers and monitors have been mainstream, but in recent years, such uses have also been extended to outdoor devices such as home video cameras and car navigation systems. In these outdoor liquid crystal display devices,
For example, reliability higher by 20 ° C. in temperature than indoor use is required.

As described above, in recent years, the performance required for the backlight of the liquid display device has been greatly changed, and in particular, the temperature is required to have a durability higher by 30 to 50 ° C. than before. In a high-temperature durability test of the liquid crystal display device, a decrease in luminance due to the lamp reflector was observed. Inspection of the lamp reflector revealed that the reflection surface was clouded.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a reflector used for a lamp reflector of a backlight of a liquid crystal display device, which prevents the reflection surface from being clouded at high temperatures and prevents the reflection surface from being clouded. This is to eliminate a decrease in the luminance of the backlight. More specifically, the purpose of the present invention is to obtain a reflection surface free from white turbidity even when a high-temperature test at 180 ° C. is performed for one hour in a reflector composed of a polyester film / silver thin film layer / adhesive layer / support.

[0012]

That is, the present inventors have conducted intensive studies in order to solve such a problem, and as a result, oligomers contained in the polyester film are precipitated on the surface at a high temperature to emit light. I found that it appeared cloudy due to diffuse reflection. Further, by applying an ultraviolet-curable acrylic resin or a hardener-curable silicone resin comprising two liquids of a main agent and a hardener to the surface of the polyester film, it is possible to prevent oligomers from depositing on the surface and prevent cloudiness. Was found. The present invention has been made based on such findings.

That is, the present invention relates to (1) that the oligomer precipitation preventing layer (A), the polyester film (B) and the silver thin film layer (C) are formed in the order of ABC, and that the A side is a reflecting surface. (2) The oligomer precipitation preventing layer (A), the polyester film (B), the silver thin film layer (C), the adhesive layer (D), and the support (E) are formed in the order of ABCDE. (3) (1) wherein the A side is a reflecting surface.
Alternatively, the reflector according to any one of (2), wherein the reflector is bent so that the oligomer precipitation preventing layer (A) side is concave and a surface having a radius of curvature of 5 mm or less is formed. Body.

First, the accompanying drawings will be described. FIG. 1 is a structural sectional view of the simplest reflector of the present invention. The oligomer deposition preventing layer 10, the polyester film 20, and the silver thin film layer 30 are from the reflection surface side. FIG. 2 is a structural sectional view showing an example of the reflector of the present invention. A metal plate 50 as a support was bonded to the silver thin film layer side of the reflector of FIG. 1 with an adhesive layer 40.

As a method of manufacturing the reflector shown in FIG.
A silver thin film layer 30 is formed on one surface of the polyester film 20, an adhesive layer 40 is applied to the silver thin film layer surface, and a curable resin layer 10 is applied to a surface of the polyester film 20 opposite to the silver thin film layer. A method of laminating the adhesive layer 40 and the metal plate 50 is exemplified. Adhesive layer 40 and metal plate 50
Is generally performed after application of the adhesive, but in addition, the application step and the lamination step can be performed separately. For example, when a thermoplastic polyester-based adhesive is used, lamination can be performed at any time by melting the applied adhesive with a hot roll. It is also possible to apply the curable resin layer 10 on one side of a polyester film in advance and then form a silver thin film layer.

The reflector shown in FIG. 3 can be manufactured by using a polymer film 60 instead of the metal plate 50 in FIG. 2 as a support, and further applying a light shielding layer 70 on the polymer film 60. .

The reflector shown in FIG. 4 uses a film in which a metal layer 80 is formed on the polymer film 60 by vapor deposition or the like instead of the polymer film 60 in FIG. 3, and the metal layer side is the adhesive layer side. It can be manufactured by laminating adjacent to.

The reflector shown in FIG. 5 is obtained by laminating a film in which the metal layer 80 is formed on the polymer film 60 by vapor deposition or the like in FIG. 4 with the polymer film side adjacent to the adhesive layer side. Can be manufactured.

FIG. 6 is a schematic view showing an example of use of the curved reflector of the present invention. Here, an example of use in a backlight of a liquid crystal display device has been described. A curved reflector (lamp reflector) 90 of the present invention is used so as to surround the lamp 100.

The term "reflector" as used herein refers to an object that returns light incident on the reflector to the original medium. Here, an object that returns 90% or more of light in the visible region to the original medium, and more preferably an object that returns 92% or more of light in the visible region to the original medium.

The outline of the reflection by the reflector of the present invention will be described with reference to FIG. 1. Most of the light incident from the curable resin layer 10 side passes through the curable resin layer 10 and the polyester film 20, and When the thin film layer 30 is reached,
The light is reflected at 0, passes through the polyester film 20 and the curable resin layer 10, and returns to the original medium again.

The oligomer precipitation preventing layer in the present invention is a layer for preventing the oligomer in the polyester film from depositing on the reflecting surface of the reflector at a high temperature and causing cloudiness, and is, for example, a curable resin.

The curable resin in the present invention includes a homopolymer or a copolymer such as a phenol resin, a xylene resin, a urea resin, a melamine resin, an unsaturated polyester resin, an epoxy resin, a silicone resin, or a resin containing these. However, the resin is not limited to these resins. For example, a thermoplastic resin may be used as long as it has a crosslinked structure such as a resin crosslinked by a curing agent (eg, an ultraviolet curable acrylic resin). Although the details of the reason why the curable resin can prevent cloudiness are unknown, imagining that oligomer precipitation occurs remarkably at or above the glass transition temperature of the polyester film, the glass transition temperature of the curable resin is reduced due to its cross-linked structure. It is thought that the precipitation of the oligomer was suppressed by this.

The optical characteristics of the curable resin have a wavelength of 550 nm.
Is preferably 80% or more. More preferably, the light transmittance is 80% or more for light having a wavelength of 500 to 600 nm, and still more preferably, the light transmittance is 8 for light having a wavelength of 400 to 800 nm.
0% or more. If the light transmittance is lower than 80%, the reflectance of the reflector is less than 90%, which is not preferable in terms of performance as a reflector.

As a method for forming the curable resin, a roll coating method capable of continuously applying a roll-shaped polyester film is preferably used. As a coating method,
The bar coating method, the Meyer bar coating method, the reverse coating method, the gravure coating method, the die coating method, and the like can be cited, and these consider the type of the curable resin to be used, the viscosity, the coating amount, the coating speed, the obtained surface state, and the like. Is selected.

The thickness of the curable resin is from 0.2 μm to 30 μm
Is preferably 0.5 μm to 20 μm, and more preferably 1 μm to 10 μm. If the thickness is too large, the cost increases from the viewpoint of material costs, which is not preferable. If the film is too thin and a continuous film is not formed, a sufficient effect cannot be obtained.

The method for curing the curable resin includes, but is not particularly limited to, a method using heating, a method using ultraviolet light, a method using visible light, a method using infrared light, a method using an electron beam, and a method using a curing agent. When coating is performed continuously, a method using ultraviolet rays or a method using heating is preferably used.

The oligomer deposited on the surface on the reflection surface side is
It is preferably less than 20 mg / m ² after a high temperature test at 180 ° C. × 1 hour. More preferably 15 mg / m ²
And even more preferably less than 10 mg / m ² . If the precipitation amount of the oligomer is larger than this, the reflection surface becomes cloudy, which may impair the performance as a reflector.

Examples of the polyester film of the present invention include films generally used at present, such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). It is not necessarily limited to these, and refers to a polymer film containing a polyester resin as a main component or containing a polyester.

The thickness of the polyester film is not limited, but is preferably about 10 to 200 μm, more preferably about 10 to 100 μm, and still more preferably about 25 to 50 μm. The optical properties of the polyester film used are preferably such that the light transmittance at a wavelength of 550 nm is 80% or more. More preferably, the light transmittance is at least 80% for light having a wavelength in the range of 500 to 600 nm, and still more preferably 400 to 600 nm.
The light transmittance is 80% or more for light in the range of 800 nm. If the light transmittance is lower than 80%, the reflectance of the reflector is less than 90%, which is not preferable in terms of performance as a reflector. The present inventors have already disclosed that the polyester film preferably has a property of absorbing ultraviolet rays in order to improve the light resistance of silver (JP-A-5-162227, US-5276600).

As a method of forming the silver thin film layer, there are a wet method and a dry method. The wet method is a general term for the plating method, and is a method of depositing silver from a solution to form a film. Specific examples include a silver mirror reaction. On the other hand, the dry method is a general term for a vacuum film forming method, and if specifically exemplified, a resistance heating type vacuum deposition method, an electron beam heating type vacuum deposition method, an ion plating method, an ion beam assisted vacuum deposition method,
There is a sputtering method and the like. In particular, a vacuum film forming method capable of a roll-to-roll method for continuously forming a film is preferably used in the present invention.

In the vacuum deposition method, a silver raw material is an electron beam,
Melt by resistance heating, induction heating, etc., raise the vapor pressure,
Preferably, it is deposited on the surface of the substrate at 0.1 mTorr (about 0.01 Pa) or less.

In the ion plating method, a gas such as argon is introduced into a vacuum at a pressure of 0.1 mTorr (about 0.01 Pa) or more, a high-frequency or DC glow discharge is caused, and a bias is applied to the substrate to perform vapor deposition. Thereby, the vapor-deposited atoms are ionized in the glow discharge and accelerated by the bias potential, so that the adhesion between the vapor-deposited substance and the substrate is increased.

As a sputtering method, a DC magnetron sputtering method, an RF magnetron sputtering method, an ion beam sputtering method, an ECR sputtering method, a conventional RF sputtering method, a conventional DC sputtering method, or the like can be used. In the sputtering method, a silver plate-shaped target may be used as a raw material, and helium, neon, argon, krypton, xenon, or the like may be used as a sputtering gas, but argon is preferably used. Gas purity is 9
It is preferably at least 9%, more preferably at least 99.5%.

The thickness of the silver thin film layer is preferably from 70 to 300 nm, more preferably from 100 to 200 nm. If the thickness is too small, the thickness of silver is not sufficient, so that there is light to be transmitted and the reflectance is reduced. On the other hand, if the thickness is larger than necessary, the reflectance does not increase. Therefore, it is not preferable in terms of cost.

In the silver thin film layer, gold, copper, nickel, iron, cobalt, tungsten,
Metal impurities such as molybdenum, tantalum, chromium, indium, manganese, titanium, and aluminum may be included.
The purity of the silver layer used is 99% or more, preferably 9%.
It is at least 9.9%, more preferably at least 99.99%.

In the present invention, the film thickness can be measured by a stylus roughness meter, a repetitive reflection interferometer, a microbalance, a quartz oscillator method or the like. It is suitable for obtaining a desired film thickness. There is also a method in which the conditions for film formation are determined in advance, a film is formed on a sample substrate, the relationship between the film formation time and the film thickness is examined, and the film is controlled by the film formation time.

The present inventors have already disclosed that it is preferable to subject the polyester film to a surface treatment with a plasma containing a metal and subsequently to form a silver film in order to improve the light and heat resistance of the reflector. (Japanese Patent Laid-Open No. 09-15
0482).

After the formation of the silver thin film layer, a single metal or alloy such as chromium, nickel, titanium, aluminum, molybdenum, tungsten, or the like, or Inconel, Incoloy, Monel, for the purpose of further protecting the silver thin film layer and improving the slipperiness of the film. It is effective to laminate an alloy layer of, for example, Hastelloy, stainless steel, or duralumin to 10 nm to 30 nm.

Performing a corona discharge treatment, a glow discharge treatment, a surface chemical treatment, a roughening treatment, or the like on the polyester film surface is commonly used by those skilled in the art as a means for improving the adhesion between the silver thin film layer and the polymer film. Would be a means.

The reflectance of the reflector thus manufactured is 90.
% Or more, preferably 92% or more, and more preferably 94% or more. In the present invention, the reflectance refers to a value for light having a wavelength of 550 nm unless otherwise specified.

The adhesive (including the adhesive) used in the adhesive layer of the present invention includes polyester-based adhesives, acrylic-based adhesives, urethane-based adhesives, silicone-based adhesives, epoxy-based adhesives, and melamine-based adhesives. Adhesives and the like. It is not necessarily limited to these, and any material having a practical adhesive strength may be used. 180 as adhesive strength
It is sufficient if the measured value of the degree peel strength is 100 g / cm, preferably 500 g / cm, more preferably 1000 g / cm. If the adhesion strength is too low, when the reflector is bent to a radius of curvature of about 1 to 5 mm, the polyester film side may be raised from the metal plate or the polymer sheet, which is not preferable.

The thickness of the adhesive layer is 0.5 μm to 50 μm, preferably 1 μm to 20 μm, more preferably 2 μm to 10 μm. If the thickness is too large, the cost increases from the viewpoint of material costs, which is not preferable. If it is too thin, sufficient adhesive strength cannot be obtained.

Examples of the method of applying the adhesive include a bar coating method, a Meyer bar coating method, a reverse coating method, a gravure coating method, a die coating method, and the like. The selection is made in consideration of the coating speed, the obtained surface condition, and the like.

The reflector of the present invention has a curable resin layer (A)
A transparent protective layer may be provided thereon. With such a protective layer, the influence of external environmental factors such as surface hardness, light resistance, gas resistance, and water resistance of the reflector can be further suppressed.
Examples of substances that can be used to form such a protective layer include, for example, acrylic resins such as polymethyl methacrylate, polyacrylonitrile resins, polymethacrylonitrile resins, silicon resins such as polymers obtained from ethyl silicate, polyesters, and the like. In addition to organic substances such as resins and fluororesins, inorganic substances such as silicon oxide, zinc oxide and titanium oxide are useful. Especially 400 nm or less, preferably 38
It is preferable to laminate light having a capability of cutting light having a wavelength of 0 nm or less, preferably 10% or less, in order to prevent light deterioration (UV deterioration) of the silver layer.

As a method for forming the transparent protective layer, existing methods such as coating and laminating a film can be used. In addition, the thickness of the transparent protective layer is required to exhibit a protective effect within a range that does not reduce the light reflectivity and does not impair the flexibility. Can be

Examples of the support include a metal plate and a polymer film. As a metal plate used as a support, an aluminum plate, an aluminum alloy plate, a brass plate, a stainless plate,
A steel plate or the like may be used, but is not necessarily limited to these, and is selected according to the use of the reflector. For example,
Aluminum is lightweight, has excellent workability, and has high thermal conductivity, and can effectively release the heat to the atmosphere, so that it can be suitably used as a reflector used in a backlight of an LCD of a notebook computer or the like. Since aluminum alloy is lightweight and has high mechanical strength, it can be suitably used for a reflector that also serves as a structural member. Since stainless steel has high mechanical strength and excellent corrosion resistance, it is suitably used for applications requiring thinner materials, such as reflectors used outdoors. Brass (brass), that is, a copper-zinc alloy, is preferably used for a reflector that requires grounding because of its high mechanical strength and easy soldering. Since steel plates are inexpensive, they are suitably used for reflectors for fluorescent lamps and the like, which are applications where cost is prioritized.

The thickness of the metal plate as the support is preferably thin from the viewpoint of cost reduction and easiness of bending, and is thick from the viewpoint of easy handling and shape retention when laminating with a silver thin film layer or the like. Is better. The preferred thickness of the metal plate is 0.05 mm to 5 mm, more preferably 0.1 mm to 1 mm, and even more preferably 0.1 mm to 1 mm.
It is 2 mm to 0.8 mm.

Examples of the polymer film used for the support include biaxially oriented polypropylene, polyethylene terephthalate (PET), and polyethylene naphthalate (PE).
N), polybutylene terephthalate (PBT), acrylic resin, methacrylic resin, polyether sulfone (P
ES), polyetheretherketone (PEEK), polyarylate, polyetherimide, polyimide and the like homopolymer or copolymer. Particularly preferred is a polyethylene terephthalate film,
When the polymer film is the outermost layer, those having a white appearance are preferred. The thickness of the polymer film is preferably thinner from the viewpoint of cost reduction and easiness of bending, and the thickness is better from the viewpoint of handling (handling) and shape retention when laminating with a silver thin film layer or the like. . Preferred film thickness is 5 μm to 500 μm, more preferably 10 μm to 200 μm, and 15 μm to 100 μm
Is preferably used.

It is preferable to apply a resin containing a white pigment such as titania or magnesia to the polymer film as a light shielding layer. Further, it is preferable to apply a metal deposition film (metal layer). These have a role in preventing light from the lamp from leaking due to defects (such as pinholes) existing in the silver thin film layer.

The structure of the silver reflector of the present invention and a typical method for evaluating the composition will be described below. The thickness of each part of the curable resin layer, the polyester film, the silver thin film layer, the adhesive layer, and the support is determined by using a transmission electron microscope (TE
M) or directly by observing with a scanning electron microscope (SEM). Material analysis of each part of the curable resin layer, polyester film, silver thin film layer, adhesive layer, and support is performed by performing infrared spectroscopy (IR) and X-ray microanalyzer (EPMA) on each layer of the cross-sectional sample. it can. Further, the internal material analysis can be performed by peeling off the interface or dissolving an unnecessary portion with a solvent to expose a necessary portion. Material analysis of the silver thin film layer and the support can be performed by X-ray fluorescence spectroscopy (XRF). Further, an X-ray microanalyzer (EPMA) can perform elemental analysis of a portion finer than X-ray fluorescence spectroscopy. Further, if the polyester film on which the silver thin film layer is formed is peeled off from the adhesive layer to expose the silver thin film layer, composition analysis and depth profile can be obtained by Auger electron spectroscopy (AES), and the thickness can be reduced. You can also know.

[0052]

EXAMPLES The samples shown in the following examples and comparative examples were subjected to a high temperature test. Further, the amount of oligomer precipitated on the sample surface was determined. Example 1 An ultraviolet-curable acrylic resin was applied to one surface of a polyethylene terephthalate film (manufactured by Teijin Limited, product number HB-3, thickness 25 μm). The coating thickness is 4μm
And

Example 2 Polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product number E5001, thickness 25 μm)
m), a two-pack type modified silicone resin was applied to one surface.
The coating thickness was 1 μm.

Example 3 One side of a polyethylene terephthalate film (manufactured by Toray, product number T-60, thickness 25 μm) was coated with a urethane acrylic resin. Coating thickness is 3μm
And

[Example 4] Polyethylene naphthalate film (manufactured by DuPont, trade name Caladex, product number 103)
0, a thickness of 25 μm) was coated with an ultraviolet curable acrylic resin. The coating thickness was 4 μm.

Comparative Example 1 A polyethylene terephthalate film (manufactured by Teijin Limited, part number HB-3, thickness 25 μm) was tested as it was.

Comparative Example 2 Polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product number E5001, thickness 25 μm)
m) was tested as is.

Comparative Example 3 A polyethylene terephthalate film (manufactured by Toray, product number T-60, thickness 25 μm) was tested as it was.

[Comparative Example 4] Polyethylene naphthalate film (manufactured by DuPont, trade name Caladex, product number 103)
0, and a thickness of 25 μm).

1. High-temperature test A sample having a size of 50 mm × 50 mm was fixed to an aluminum plate having a thickness of 0.3 mm with heat-resistant tape on all sides and left in a high-temperature bath at 180 ° C. for 1 hour. The sample surface after the test was observed with an optical microscope. Optical micrographs showing the state of the sample surface after the high temperature test are shown in FIGS. In Example 1, the surface on the curable resin side was observed. The bar at the lower right of the figure represents a length of 25 μm. As shown in FIGS. 8 to 11, in Comparative Examples 1 to 4, crystalline precipitates having a size of several to several tens of μm were observed. Incidentally, the white blurred image having a size of 20 to 30 μm is a defocused image of the precipitate on the back surface of the sample, and may be ignored here.
The crystalline precipitate was analyzed by infrared spectroscopy (microscopic IR method) and found to be an oligomer of the used polyester film. On the other hand, in Examples 1-4, the oligomer of the polyester film observed in Comparative Examples 1-4 was not observed. FIG. 7 shows an optical microscope photograph based on Example 1. Although fillers or defects considered to be defects in the film are slightly reflected, no crystalline precipitate is observed in the comparative example. From these results, it can be seen that the precipitation of the oligomer was suppressed by the curable resin.

[0061] 2. Oligomer Deposition Amount The oligomer deposition amount was further determined for the examples and comparative examples. A sample having a size of about 10 cm × 10 cm was left in a high-temperature bath at 180 ° C. for 1 hour, and the weight of the oligomer deposited on the sample surface was determined from the weight difference before and after wiping the oligomer.
Although ethanol was used as the wiping solvent this time, chloroform or the like may be appropriately selected and used. Experimental procedure: Heat the sample for 1 hour in a high temperature bath at 180 ° C.・ After removing dust and the like adhering to the surface with a static elimination blower, measure the weight. -The surface was sufficiently wiped with a cloth impregnated with ethanol (the curable resin surface was wiped in Example 1, and the front and back surfaces of the sample were wiped in Comparative Examples 1 to 4). -Heat in a high-temperature bath at 180 ° C for 5 minutes to completely evaporate the used wiping solvent (ethanol).・ After removing dust and the like adhering to the surface with a static elimination blower, measure the weight. Table 1 shows the results.

[0062]

[Table 1] * The deposition weight was determined by the following equation. Deposition weight (g / m ² ) = (W 0 −W) / W × A where A is the weight of the sample when the evaluated (wiped) area is 1 m ² . In the case of Example 1, the density of PET is 1.4 g / m ³ , the thickness is 25 μm, the density of the curable resin is 1.19 g / m ³ , the thickness is 4 μm, and the evaluated surface is one side, A = 39.8 g / m ² is obtained.
Similarly, in Comparative Examples 1 to 3, the PET density was 1.4 g.
/ M ^3, a thickness of 25 [mu] m, since the evaluated surface is a surface and a back surface, A = 17.5g / m ² is, in Comparative Example 4, the density of the PEN is 1.36 g / m ^3, the thickness was 25 [mu] m Yes, since the evaluated surface is the front surface and the back surface, A = 1
7.0 g / m ² is obtained.

As shown in Table 1, in the comparative example, 40 to ⁷ per m ² was used.
Although 0 mg of the oligomer is precipitated on the surface, it can be seen that no precipitate is observed in Example 1 using the curable resin.

[0064]

In the reflector comprising the polyester film / silver thin film layer / adhesive layer / support, on the side of the polyester film opposite to the silver thin film layer, an ultraviolet curable acrylic resin or a two-pack type By applying a so-called curable resin such as a silicone resin, it was possible to prevent the reflection surface from becoming cloudy at high temperatures.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a reflector of the present invention.

FIG. 2 is a structural sectional view showing an example of the reflector of the present invention.

FIG. 3 is a structural sectional view showing an example of the reflector of the present invention.

FIG. 4 is a structural sectional view showing an example of the reflector of the present invention.

FIG. 5 is a structural sectional view showing an example of the reflector of the present invention.

FIG. 6 is a schematic view showing an example of a usage example of the curved reflector of the present invention.

FIG. 7 is a drawing showing an optical microscope photograph showing a state of a sample surface after a high temperature test. The length of the lower right bar is 25μ
m.

FIG. 8 is a drawing showing an optical microscope photograph showing a state of a sample surface after a high temperature test. The length of the lower right bar is 25μ
m.

FIG. 9 is a drawing showing an optical microscope photograph showing a state of a sample surface after a high temperature test. The length of the lower right bar is 25μ
m.

FIG. 10 is a drawing showing an optical microscope photograph showing a state of a sample surface after a high temperature test. The length of the lower right bar is 25
μm.

FIG. 11 is a drawing showing an optical microscope photograph showing a state of a sample surface after a high temperature test. The length of the lower right bar is 25
μm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Curable resin 20 Polyester film 30 Silver thin film layer 40 Adhesive layer 50 Metal plate 60 Polymer film 70 Light shielding layer 80 Metal layer 90 Curved reflector (lamp reflector) 100 Lamp 110 Lens film 120 Diffusion sheet 130 Light guide plate 140 Reflective sheet

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) 2H042 DA04 DA11 DA18 DC02 DC03 DC08 DD05 DE00 DE04 4F073 AA05 AA16 BA23 BB01 BB09 EA65 EA76 HA11 4F100 AB24C AK25A AK41B AR00A AT00D BA10A BA10C BA10D CB00 J48A12

Claims (6)

[Claims] 1. A reflector characterized in that an oligomer precipitation preventing layer (A), a polyester film (B) and a silver thin film layer (C) are formed in the order of ABC, and the A side is a reflecting surface. 2. An oligomer precipitation preventing layer (A), a polyester film (B), a silver thin film layer (C), an adhesive layer (D), and a support (E) are formed in the order of ABCDE, and
A reflector, wherein the A side is a reflection surface. 3. The reflection according to claim 1, wherein the amount of the oligomer deposited on the surface on the side A after the high-temperature test at 180 ° C. for one hour is less than 20 mg / m ^2. body. 4. The reflector according to claim 1, wherein the oligomer precipitation preventing layer (A) is a curable resin. 5. The reflector according to claim 1, wherein the reflector is formed such that the oligomer precipitation preventing layer (A) has a concave surface and a radius of curvature of 5 mm or less. Characteristic curved reflector. 6. The curved reflector according to claim 5, wherein the reflector is used as a lamp reflector of a backlight of a liquid crystal display device.