JPH08127100A - Reflector - Google Patents

Abstract

PURPOSE: To form a reflector susceptible to drawing processing by laminating a transparent polymeric film having predetermined tensile elongation and tensile strength, a silver membrane layer having predetermined thickness, an adhesive layer and a plate-shaped molded object in this order without generating a crack in the film. CONSTITUTION: A reflector is constituted of a transparent polymeric film 10, a silver membrane layer 20, an adhesive layer 30 and a plate-shaped molded object 40. As the transparent polymeric film 10, a polymeric film with tensile elongatioan of 150-450% and tensile strength of 200-1500kg/cm<2> , for example, a polypropylene film is used. The transmissivity to light with a wavelength of 550nm of the polymeric film 10 is set to 85% or more. The thickness of the silver membrane layer 10 is set to 100-300nm. After this silver membrane layer 20 is formed by a wet method, it is pref. to protect the silver membrane layer 20 by laminating Inconel on the layer 20 in a thickness of about 10-30nm. The adhesive layer 30 is formed from a silicone adhesive using a catalyst and the plate-shaped molded object is formed from aluminum or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reflective silver reflector, and more particularly to a drawable reflector.

[0002]

2. Description of the Related Art Mirror-polished aluminum plates are often used as reflectors for fluorescent lamps and incandescent lamps.
However, since aluminum has a problem that the reflectance is not sufficient, there is a reflective film in which silver is formed as a thin film layer on a transparent polymer film instead of aluminum. A reflection plate obtained by applying an adhesive to a silver surface and laminating the reflection film on, for example, an aluminum plate has a reflectance of 90% or more and has excellent bending workability and punching workability (Japanese Patent Laid-Open No. 1-299029). , JP-A-5-162227). However, since many reflectors having a curved surface are used for the purpose of focusing light, a reflector having a curved surface is industrially very useful.
Specifically, it is preferable that curved surface processing of SR 50 mm is possible. Then, the inventors of the present invention encountered a new problem that, when performing a drawing process to obtain a reflector having a curved surface using the reflector, a crack was formed in the film and the intended reflector could not be obtained. did.

[0003]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that cracks in a transparent polymer film cause stress when the film is drawn. Found that
As a result of further research, they have found that the polymer film can be solved by using a polymer film having an appropriate tensile elongation property and an appropriate tensile strength, and arrived at the present invention.

[0004]

That is, the present invention has been made to solve the above problems, and the gist thereof is a transparent polymer film (A) having a thickness of 100 to 300 nm. At least A, B, C and D of the silver thin film layer (B), the adhesive layer (C) and the plate-shaped molded body (D) of
Is a reflector formed of ABCD, and the transparent polymer film has a tensile elongation of 150% to 450% and a tensile strength of 200 to 1500 kg / cm.
A reflector having a number of ² or more, in particular, a reflector having a transmittance of 85% or more for a light having a wavelength of 550 nm of a transparent polymer film, and a plate-shaped molded body made of aluminum or an aluminum alloy. Is a reflector.

The constitutional requirements of the present invention will be described below. First, referring to the attached drawings, FIG. 1 shows a layer structure of a reflector according to the present invention, in which 10 is a transparent polymer film, 20 is a silver thin film layer, 30 is an adhesive layer, and 40 is It is a plate-shaped molded body. As the material of the polymer film (A) in the present invention, polypropylene, polyethylene, polyester, polyamide, polyether sulfone, polycarbonate, fluorine film and the like can be used.
It is not necessarily limited to these types, but the point is that the tensile elongation is 150% to 450%, more preferably 200% to 400%, even more preferably 250% to 400%, and The tensile strength is 200 to 1500 kg / cm ² , more preferably 300 to 1000 kg / cm ² , and any glass having a glass transition temperature that is high to some extent can be used.

If the elongation is less than this, the film is likely to be cracked at the time of drawing, and if it exceeds this, the film is wrinkled. Further, if the tensile strength is smaller than this, the film also cracks during processing, and if it exceeds this, the film becomes wrinkled. The tensile strength and the tensile elongation of the film may be measured by using the ASTM D-882 method.

Although the film thickness has no limit value,
About 25 to 150 μm is preferably used. Regarding the optical properties of the polymer film used, it is preferable that the linear transmittance of light having a wavelength of 550 nm is 85% or more and the haze value is 7% or less. More preferably, the wavelength is 500 to 70.
With respect to light in the range of 0 nm, the light transmittance is 85% or more and the haze value is 7% or less. If the light transmittance is lower than this, the total reflectance of the reflective film will not reach the desired value. Further, in order to obtain a reflector having an appropriate diffuse reflectance, the haze value of the transparent polymer film may be adjusted.

It will be understood by those skilled in the art that the polymer film preferably has the property of absorbing ultraviolet rays in order to improve the light resistance of silver. The method of forming the silver thin film layer (B) includes a wet method and a dry method. The wet method is a general term for plating methods, and is a method of depositing silver from a solution to form a film. Specific examples include silver mirror reaction and the like. On the other hand, the dry method is a general term for a vacuum film forming method, and if it is specifically exemplified, a resistance heating vacuum evaporation method, an electron beam heating vacuum evaporation method, an ion plating method, an in-beam assisted vacuum evaporation method. , The sputtering method, etc. In particular, a vacuum film forming method capable of a roll-to-roll method of continuously forming a film is preferably used in the present invention.

In the vacuum deposition method, the silver raw material is an electron beam,
Melt by resistance heating, induction heating, etc. to raise the vapor pressure,
Preferably, it is vapor-deposited on the surface of the substrate at 0.1 mTorr (about 0.01 Pa) or less. At this time, a gas such as argon may be introduced at 0.1 mTorr (about 0.01 Pa) or more to cause high frequency or direct current glow discharge. As the 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 the raw material, and the sputtering gas may be helium, neon, argon,
Although krypton, xenon and the like can be used, argon is preferably used. The purity of the gas is preferably 99% or more, more preferably 99.5% or more.

The thickness of the silver thin film layer is 100 nm to 300 n.
m is preferable, and more preferably 100 nm to 200 nm.
Is. If it is less than this, the thickness of silver is usually sufficient if it is 70 nm or more, and there is almost no transmitted light.
Sufficient reflectance can be obtained, but when drawn, the silver film thickness becomes thin and transmitted light comes to exist. for that reason,
The silver thin film is preferably 100 nm or more. On the other hand, even if the film thickness is made thicker than 300 nm, the reflectance does not increase any more, and it tends to be saturated, and the adhesiveness of the silver layer to the polymer film is lowered, which is not preferable. Further, from the viewpoint of effective utilization of resources, it is not preferable to set the film thickness to more than 300 nm. For other purposes, you are free to make it thinner or thicker than this.

The film thickness can be measured by a stylus roughness meter, a repeated reflection interferometer, a microbalance, a crystal oscillator method, etc.
The crystal oscillator method is suitable for obtaining a desired film thickness because the film thickness can be measured during film formation. Further, there is also a method in which conditions for film formation are determined in advance, film formation is performed on a sample substrate, the relationship between film formation time and film thickness is investigated, and then the film is controlled by the film formation time. Incidentally, the silver thin film layer, gold, copper, nickel, iron, cobalt, tungsten, molybdenum, tantalum, chromium, indium, to the extent that the performance is not impaired,
Metal impurities such as manganese and titanium may be included.

After forming the silver thin film layer, for the purpose of protecting the silver layer and improving the slipperiness of the film, Inconel,
Single metal or alloy such as chromium, nickel, titanium, aluminum, molybdenum, and tungsten is 10 nm-
Those skilled in the art will understand that stacking 30 nm is effective. It will be within the design of those skilled in the art to add gold, platinum, or palladium in the range of several to several tens of atomic% for the purpose of improving the weather resistance of the silver layer. When providing the silver thin film layer on the transparent polymer film, the polymer film surface, corona discharge treatment, glow discharge treatment, surface chemical treatment,
It is understood by those skilled in the art that the surface roughening treatment is effective in improving the adhesion between the silver thin film layer and the polymer film.

The adhesive (C) used in the present invention is an adhesive which is adhered with the aid of heat or a catalyst, and specifically, silicone adhesive, polyester adhesive, epoxy adhesive, cyanoacrylate. A general adhesive such as a system adhesive or an acrylic adhesive can be used. Since the silicone-based adhesive and the polyester-based adhesive have excellent heat resistance and electrical characteristics, they can be suitably used for a reflector for stroboscope that applies a trigger. Epoxy adhesive is strong,
Since it has excellent heat resistance, it can also be suitably used.

The cyanoacrylate-based adhesive has excellent quick attack property and strength, and therefore can be used for efficient production of a reflector. These adhesives are roughly classified into a thermosetting type, a hot-melt type, and a two-liquid mixed type depending on the bonding method, but a thermosetting type or a hot-melt type capable of continuous production is preferably used. The thickness of the thermal adhesive is not particularly limited, but is usually 0.5 μm to 50 μm, preferably 1 μm to 20 μm.
It is a degree.

The polymer film (A) having the silver thin film layer (B) formed thereon and the plate-like molded body (D) are bonded to each other by coating the silver thin film layer with an adhesive, drying, and rolling the plate-shaped molded body with a roller. Laminating, is performed. There are many adhesive coating methods depending on the type of base material and adhesive agent, but the widely used are the gravure coater method and the reverse coater method. In the gravure coater method, a gravure roll, a part of which is immersed in an adhesive, is rotated, and a film fed by a backup roll is brought into contact with the gravure roll to which the adhesive is attached to perform coating. The coating amount can be adjusted by controlling the rotation speed of the roll and the viscosity of the adhesive. The reverse coater method is also a method similar to the gravure roll method, but the amount of the adhesive attached to the coating roll is adjusted by the metering roll installed in contact with the coating roll. The drying temperature and the laminating temperature of the coated adhesive vary depending on the kind of the adhesive, but when the general adhesive listed above is used, it is around 100 ° C.

The adhesive strength between the transparent polymer film having a silver thin film layer formed by this adhesive and the plate-like molded article is preferably about 100 g / cm or more as measured by 180 degree peel strength. If the adhesion strength is not reached, the transparent polymer film on which the silver thin film layer is formed is likely to be peeled off from the plate-shaped body when processed as a reflector for a strobe.

Aluminum, aluminum alloy, stainless steel, steel-zinc alloy and the like are used for the plate-shaped molded product in the present invention, and these metals have advantages and can be used as follows. It is within the range of design conditions of those skilled in the art. Aluminum is lightweight and excellent in workability, has high thermal conductivity, and can effectively dissipate heat to the atmosphere. Therefore, aluminum can be suitably used when the reflector is heated by light emission from a lamp. Since aluminum alloy is lightweight and has high mechanical strength, it can be suitably used for a reflector that requires strength. Since stainless steel has an appropriate mechanical strength and excellent corrosion resistance, it can be suitably used for a reflector for a strobe that requires touch resistance. In the case of stainless steel, for example, it is an austenitic stainless steel containing 10 to 19% by weight of chromium and 6 to 10% by weight of nickel. Steel-zinc alloy, that is, brass or brass, has a high mechanical strength and is easy to solder, so that it can be suitably used for a reflector that requires electrical terminals. In the case of brass, for example, copper 58 to 72
It is brass containing wt%. Needless to say,
Of course, a plastic plate can be used.

Thus, the reflectance of the produced reflector is typically 93% or more with respect to light having a wavelength of 550 nm, and more specifically, 93 in the range of 500 nm to 750 nm.
% Or more. The reflector according to the present invention thus formed can be suitably drawn. The drawing process is
It can be performed by hot working and cold working. The hot working is preferably performed at a temperature lower than the melting point of the polymer film. Further, more preferably cold working, in particular,
Aluminum or an aluminum alloy is preferably cold worked. Also, it goes without saying that so-called superplastic alloys are preferably used by taking advantage of processing. Hereinafter, an example of an embodiment of the present invention will be described with reference to examples.

[0019]

EXAMPLES In the following, the tensile strength and elongation of the film were measured according to ASTM D-882. The reflectance was measured with a spectrophotometer (Hitachi U-3400).

Example 1 An unstretched polypropylene film (thickness 50 μm, tensile strength 1300 kg / cm ² ,
A silver thin film having a thickness of 120 nm was formed by a vacuum vapor deposition method at an elongation of 400%. 5μm of polyester hot melt adhesive (Souken Kagaku SD Dyne 5273) on the silver deposited surface
It was applied thickly and adhered to a 0.2 mm thick aluminum plate by thermal lamination. The reflectance of the obtained sample, wavelength 55
It was 95.6% at 0 nm.

Example 2 Tetrafluoroethylene-ethylene copolymer (ETFE) film (thickness, 25 μm
A tensile strength of 450 kg / cm ² and an elongation of 330%) was obtained by a magnetron sputtering method using a pure silver target.
A silver thin film having a thickness of nm was formed. A polyester hot melt adhesive (Souken Kagaku SK Dyne 5276) was applied to the silver-formed surface in a thickness of 5 μm and adhered to an aluminum plate having a thickness of 0.3 mm by thermal lamination. The reflectance of the obtained material was 96.2% at a wavelength of 550 nm.

Example 3 A polychlorotrifluoroethylene (PCTFE) film (thickness: 25 μm, tensile strength: 410 kg / cm ² , elongation: 170%) was used, and a thickness of 130 nm was obtained by a magnetron sputtering method using a pure silver target. A silver thin film was formed. Polyester hot melt adhesive (Souken Kagaku SK Dyne 52
73) was applied to a thickness of 5 μm and adhered to a brass plate (JIS type 2) having a thickness of 0.3 mm by thermal lamination. The reflectance of the obtained sample was 96.5% at a wavelength of 550 nm.

Example 4 A 126 nm silver thin film was formed on a non-stretched polyester film (thickness: 50 μm, tensile strength: 700 kg / cm ² , elongation: 440%) by a vacuum deposition method. A polyester hot melt adhesive (Souken Kagaku SD Dyne 5273) was applied on the silver vapor-deposited surface to a thickness of 5 μm and adhered to a 0.2 mm thick aluminum plate by thermal lamination. The reflectance of the obtained sample has a wavelength of 550.
It was 94.3% in nm.

Comparative Example 1 In Example 1, instead of the unstretched polypropylene film, a stretched polypropylene film (thickness: 25 μm, tensile strength: 1300 kg) was used.
/ Cm ² , elongation 120%) to prepare a sample.

Comparative Example 2 In Example 1, instead of the unstretched polypropylene film, a stretched polyester film (thickness 25 μm, tensile strength 2500 kg /
cm ² and elongation 130%) to prepare a sample.

Comparative Example 3 A sample was prepared by using an ethylene-vinyl acetate copolymer polymer film (thickness 50 μm, tensile strength 1900 kg / cm ² , elongation 500%) instead of the unstretched polypropylene film in Example 1. It was created.

Comparative Example 4 In Example 1, a low density polyethylene film (thickness: 50 μm, tensile strength: 150 kg / cm) was used instead of the unstretched polypropylene film.
² , elongation 400%) was used to prepare a sample.

[Comparative Example 5] The reflectance of a high-brightness aluminum plate (Sumitomo Light Metal, model SL) having a thickness of 0.3 mm was measured and found to be 89.2% at a wavelength of 550 nm.

Using the samples prepared in the above Examples and Comparative Examples, a reflecting plate for an incandescent bulb was prepared by cold drawing. The shape of the manufactured lamp reflector is SR =
It has a hemispherical shape with a spherical shape of 50 mm and a reflecting surface inside the diaphragm. After the fabrication, the reflective surface was visually inspected to see if there were any defects such as cracks and wrinkles that pose a problem in practical use. The results of the above examples and comparative examples are shown in [Table 1].

[0030]

[Table 1] From the above Examples and Comparative Examples, it is understood that the present invention makes it possible to obtain a reflector that can be drawn and has a high reflectance.

[0031]

From the above Examples and Comparative Examples, it is understood that the present invention makes it possible to obtain a reflector which can be drawn and has a high reflectance.

[Brief description of drawings]

FIG. 1 is a layer structure of a reflector according to the present invention.

[Explanation of symbols]

 10 Transparent polymer film 20 Silver thin film layer 30 Adhesive layer 40 Plate-shaped molded body

Claims (3)

[Claims] 1. A transparent polymer film (A), having a thickness of 100.
At least A, B, C, and D of the silver thin film layer (B), the adhesive layer (C), and the plate-shaped molded body (D) having a thickness of up to 300 nm are ABC.
A transparent polymer film having a tensile elongation of 150% to 450%, and
A reflector having a tensile strength of 200 to 1500 kg / cm ² or more. 2. A transparent polymer film having a wavelength of 550 nm.
The reflector according to claim 1, having a light transmittance of 85% or more. 3. The reflector according to claim 1, wherein the plate-shaped molded body is aluminum or an aluminum alloy.