JP2005066937A - Functional plastic member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional plastic member having a low reflecting film excellent in peel resistance and scratch resistance formed thereto. <P>SOLUTION: Low reflecting films 1 and 2 are formed on both sides of a sheetlike transparent plastic material W. The water absorption of the transparent plastic material W is set to 0.02% or below and the hardness (Vickers hardness) of the low reflecting films 1 and 2 or a transparent conductive film 3 is 15 or above. Each of the low reflecting films or the transparent conductive film is obtained by generating ECR plasma on the side opposed to the plastic material W of a magnetron cathode and on the side opposed to the magnetron cathode of the plastic material W and performing sputtering in a high density low temperature plasma atmosphere. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a functional plastic member having a low reflection film or a transparent conductive film formed on the surface.

As materials for lenses, lighting covers, liquid crystal panel covers, goggles and the like, plastics having excellent translucency such as acrylic and polycarbonate have been conventionally used. On the other hand, since plastic is softer than glass, its surface is easily damaged. Therefore, a technique for forming an organic hard coat layer on the surface of a plastic plate is conventionally known.
For example, in Patent Document 1, a coating composition is prepared by adding a surfactant, a polymerization initiator, etc. to a crosslinkable mixture composed of polyethylene glycol di (meth) acrylate, and this is applied to the surface of a plastic plate. A technique has been proposed in which an uncured film is formed, and the uncured film is irradiated with ultraviolet rays to cause a crosslinking reaction, and the uncured film is cured to form a hard coat layer.

Conventionally, a transparent conductive film or low reflection film (AR film) made of ITO (indium / tin oxide) is formed on the surface of acrylic or polycarbonate plates (sheets) as a display unit for touch panels or mobile phones. Is used.
For example, Patent Document 2 proposes a technique for directly forming an ITO film or an AR film on an acrylic or polycarbonate substrate using an RF magnetron sputtering apparatus.

WO96 / 41831 JP-A-9-305313 Paragraphs 0037-41

Serious problem that ITO film or AR film as disclosed in Patent Document 2 formed on a plastic substrate directly on a plastic substrate is peeled off over time when used in a display unit such as a mobile phone. Has occurred.
As a result, at present, the organic hard coat layer disclosed in Patent Document 1 is formed on the surface of the plastic substrate, the ITO film or the AR film is formed on the organic hard coat layer, and the hardness of the ITO film or the AR film itself. However, since the scratch resistance is not sufficient, a protective film is further formed on these functional films.

The above-mentioned organic hard coat layer is generally formed by a wet method (sol-gel method). The ITO film or AR film formed on the organic hard coat layer is formed by a CVD method or the like in consideration of film formation efficiency. It is formed by a PVD method such as sputtering. However, since the apparatus for performing the wet process and the PVD process such as CVD or sputtering is completely different, the production line becomes large.

The present inventor searched for the cause of peeling or scratching when an ITO film or AR film was directly formed on a plastic substrate, and came to the conclusion that there were two causes.
One is moisture contained in the plastic substrate, the water absorption rate of acrylic (PMMA) is 0.27% to 2.0%, and the water absorption rate of polycarbonate (PC) is 0.15% to 0.4%. When functional films such as ITO film and AR film are formed, even if the functional film is firmly bonded to the plastic substrate, the plastic substrate absorbs moisture in the air over time and functions as a plastic substrate under the influence of the absorbed moisture. Bonding at the interface with the film is broken and peeling occurs.
The other is the hardness (denseness) of the functional film itself. The functional film formed by the wet method or the CVD method has low hardness, and is easily peeled off or scratched by an external force such as scratching.

Therefore, the functional plastic member according to the present invention has a low reflection film having a hardness (Vickers hardness) of 15 or more on the surface of a film-like, sheet-like or plate-like transparent plastic material having a water absorption of 0.02% or less. A transparent conductive film is directly formed.
Such a functional plastic member cannot be obtained by a conventional method as described below.

ZEONOR (manufactured by Nippon Zeon) and ARTON (manufactured by Nippon Synthetic Rubber) are commercially available as plastic materials having a water absorption rate of 0.02% or less, but these plastic materials are inferior in heat resistance and have a low reflective film denseness. If the film is formed by the sputtering method currently being carried out in order to increase the thickness, the plastic material will be deformed due to the high temperature. On the other hand, as described above, the desired hardness cannot be obtained by the wet method or CVD.

In order to form a dense functional film on the surface of the plastic material without increasing the temperature by sputtering, it is necessary to control the plasma density high and the plasma temperature low.
Conventionally, there has been no sputtering method that satisfies such conditions, but it has been made possible by the plasma sputtering apparatus proposed by the present inventor in Japanese Patent Application No. 2002-206087.

That is, using an RF magnetron sputtering apparatus, ECR (electron cyclotron resonance) plasma is generated on the side facing the transparent plastic material near the magnetron cathode and on the side facing the magnetron cathode near the transparent plastic material. A functional plastic member in which two low-temperature and high-density ECR plasmas are formed as reinforcement-supporting plasmas, and a low-reflective film with excellent peel resistance and scratch resistance is formed on the surface of the plastic material without deformation. Can be obtained.

As described above, in the functional plastic member according to the present invention, the low reflective film or the transparent conductive film formed on the surface does not peel over time, and the hardness of the low reflective film or the transparent conductive film itself is high. Therefore, the low reflection film or the transparent conductive film also has a function of a hard coat.
Therefore, the functional plastic member according to the present invention is extremely effective as a substitute for a display unit of a mobile phone or various monitors, a half mirror, and various window glasses.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an enlarged cross-sectional view of a functional plastic member according to the present invention. In the embodiment shown in FIG. 1 (a), low reflection on both surfaces (single surface is acceptable) of a transparent plastic material W having a plate shape. Films 1 and 2 are formed, and in the embodiment shown in FIG. 1B, a transparent conductive film 3 is formed on one surface (or both surfaces) of a transparent plastic material W having a plate shape, and FIG. In the embodiment shown in FIG. 2A, a portion functioning as the low reflection film 1 and a portion functioning as the transparent conductive film 3 are laminated on one side (or both sides) of the transparent plastic material W having a plate shape. In the example, a boundary layer between a portion functioning as the low reflection film 1 and a portion functioning as the transparent conductive film 3 is a part of the low reflection film 1 and a part of the transparent conductive film 3, and the low reflection film 1 is separately provided. Compared with the case where the transparent conductive film 3 is formed, the same effect can be achieved by reducing the number of layers. It has to so that. An example of the boundary layer that exhibits both functions is SiO ₂ .

  Examples of the transparent plastic material W include polyolefin-based low water absorption plastics such as ZEONOR manufactured by Nippon Zeon Co., Ltd. and ARTON manufactured by Nippon Synthetic Rubber Co., Ltd., but are not limited thereto. % Or less, the desired functional plastic member can be obtained. The transparent plastic material W includes a colored material.

The specific configuration of the low reflection film 1 shown in FIG. 1A is P / Si (10 nm) / SnO ₂ (100 nm) / TiO ₂ (20 nm) / SiO ₂ (100 nm).
The configuration of the transparent conductive film 2 shown in FIG. 1B is P / SiO ₂ (10 nm) / ITO (15 nm).
Further, the specific configuration of the film shown in FIG. 1C will be described later with reference to FIGS.

2 is a perspective view of the main part of the sputtering apparatus used for the production of the functional plastic member according to the present invention, FIG. 3 is a side view of the main part of the sputtering apparatus shown in FIG. Are disposed in a part of the in-line type film forming system that is transported by the transporting roller 11. The transporting rollers 11 that transport the plate-shaped plastic material W are disposed at the bottom of the evacuable chamber 10. A magnet array 20 is disposed between the transport rollers, and a pair of rotary magnetron cathodes (targets) 30 are disposed in parallel and spaced apart in the region where the magnet array 20 is disposed and above the plastic material W to be transported. Further, the magnet array 20 and the rotary magnetron cathode are used with reference to the conveying direction of the plastic material W. De is arranged an antenna group 40 for radiating microwaves to the downstream side of the (target) 30.

  In the magnet array 20, four rod-shaped magnets 21 are arranged in two rows in the conveying direction of the plastic material W and four in the width direction (total of eight). Each bar-shaped magnet 21 is fixed so that adjacent S poles and N poles are alternated. By doing so, the lines of magnetic force that form the arch-shaped mirror magnetic field and the traveling direction of the microwaves are substantially the same direction, and the ECR (electron cyclotron resonance) plasma is on the side of the plastic material W facing the magnetron cathode 30. It occurs effectively near the surface.

As a magnetron cathode, a planar magtron cathode having a long plate shape is generally used in a sputtering apparatus. However, the planar magtron cathode has a corner portion, and thus abnormal discharge occurs. Not suitable for the production of functional plastic parts. Therefore, in the present invention, the rotary magnetron cathode 30 is used.

The rotary magnetron cathode (target) 30 supports a cylindrical target 32 on a rotating shaft 31, and a magnet array 33 is disposed inside the cylindrical target 32. Similar to the magnet array 20, the magnet array 33 has a plurality of rod-shaped magnets arranged so that adjacent S poles and N poles are alternately arranged. As a result, the magnetic field lines forming the arcuate mirror magnetic field and the traveling direction of the microwaves are substantially the same as described above, and the surface of the magnetron cathode 30 on the side where the ECR (electron cyclotron resonance) plasma faces the plastic material W. It occurs effectively in the vicinity.

  The antenna group 40 is divided into three parts in the width direction of the plastic material W, and each divided part is connected to a microwave oscillator of 2.45 GHz, for example, via a waveguide 41, and each divided body has a microwave. Slots are formed at intervals of 1/2 of the wavelength (λ). The structure of the antenna is not limited to that shown in the figure, and is arbitrary such as a helical type.

  As described above, in the present invention, as shown in FIG. 2, on the side facing the plastic material W in the vicinity of the magnetron cathode 30 and on the side facing the magnetron cathode 30 in the vicinity of the plastic material W, respectively. Since ECR plasma is generated, sputtering is performed in a high-density and low-temperature plasma atmosphere.

  In the above, in order to form a multilayer low-reflection film or transparent conductive film, the above sputtering apparatus is arranged in the number of layers along the transport line, and the target of each sputtering apparatus is used as a material for forming each layer. .

Next, the characteristics of the products 1 and 2 of the present invention and the comparative example are compared. Here, the structure of the product of the present invention and the comparative example is as follows.
Invention product 1: An AR film (low reflection film 1 in FIG. 1) is formed on the surface of a polyolefin resin (Zeonor) having a water absorption rate of 0.02% or less in a state in which ECR plasma is generated above and below the present invention.
Invention product 2: An ITO film (transparent conductive film 3 in FIG. 1) is formed on the surface of a polyolefin resin (Zeonor) having a water absorption of 0.02% or less in a state where ECR plasma is generated in the upper and lower sides of the present invention.
Comparative Example 1: AR film is formed by a general CVD method on a polycarbonate plate (PC: water absorption rate 0.15% to 0.4%) Comparative example 2: Acrylic plate (PMMA: water absorption rate 0.27% to 2.0%) AR film is formed by general CVD Comparative example 3: AR film is formed on polycarbonate plate by general sputtering method Comparative example 4: AR film is formed on acrylic plate by general sputtering Formation Comparative Example 5: AR film is formed on polycarbonate plate by upper and lower ECR (method of the present invention) Comparative Example 6: AR film is formed on acrylic plate by upper and lower ECR (method of the present invention) Comparative Example 7: Zeonor is AR Comparative Example 8: Formation of ITO Film on Zeonore by General CVD Method Comparative Example 9: Formation of AR Film on Zeonore by General Sputtering Method Comparative Example 10: Zeonore ITO film is formed by a general sputtering method. The product of the present invention and the comparative example are items "Vickers hardness", "Pencil test (abrasion resistance)", "Warpage", "Adhesion (tape peeling / cross cut test)", "Water resistance", "Moisture resistance" The results of comparison for "are shown in the following (table).
Note that none of the resin plates is hard-coated on the surface.

4 to 6 show the relationship between the wavelength and the visible light reflectance of the multilayer film composed of the structure shown in FIG. 1C, that is, the portion exhibiting the low reflection function and the portion exhibiting the conductive function. It is a graph which shows.
It can be seen that the functional film having a four-layer structure shown in FIG. 4 has extremely low reflectivity in the visible light region and at the same time has a small surface resistance value and excellent conductivity. Particularly in this embodiment, the Si / SnO ₂ / TiO ₂ / SiO ₂ / ITO layer exhibits a low reflection function, and the SiO ₂ / ITO layer exhibits a conductive function.
Further, the functional films having a three-layer structure shown in FIGS. 5 and 6 have a layer structure of TiO ₂ / SiO ₂ / ITO and SnO ₂ / SiO ₂ / ITO, respectively, and have a four-layer structure in a low reflection function. Although it is slightly inferior, it is remarkably superior in terms of cost and durability compared to conventional products.

  The functional plastic member of the present invention can be suitably used as a lens, lighting cover, liquid crystal panel cover, goggles and the like.

(A) And (b) is an expanded sectional view of the functional plastic member which concerns on this invention. The perspective view of the principal part of the sputtering device used for manufacture of the functional plastic member which concerns on this invention. Side view of the main part of the sputtering apparatus shown in FIG. Graph showing the relationship between wavelength and visible light reflectance for a multilayer film consisting of a part that exhibits a low reflection function and a part that exhibits a conductive function Graph similar to FIG. 4 when the film composition is changed Graph similar to FIG. 4 when the film composition is changed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Low reflection film, 3 ... Transparent electrically conductive film, 10 ... Chamber, 11 ... Conveyance roller, 20 ... Magnet array, 21 ... Bar magnet, 30 ... Rotary magnetron cathode (target), 31 ... Rotary shaft, 32 ... Cylindrical target, 33 ... magnet array, 40 ... antenna group, 41 ... waveguide, W ... transparent plastic material.

Claims (5)

In a functional plastic member in which a low reflection film is formed on the surface of a film-like, sheet-like or plate-like transparent plastic material, the water absorption rate of the transparent plastic material is 0.02% or less, and the low reflection film is transparent. A functional plastic member formed directly on the surface of a plastic material and having a Vickers hardness of 15 or more. In a functional plastic member in which a transparent conductive film is formed on the surface of a film-like, sheet-like or plate-like transparent plastic material, the water absorption rate of the transparent plastic material is 0.02% or less, and the transparent conductive film is transparent A functional plastic member formed directly on the surface of a plastic material and having a Vickers hardness of 15 or more. In a functional plastic member in which a multilayer film is formed on the surface of a film-like, sheet-like or plate-like transparent plastic material, the water absorption rate of the transparent plastic material is 0.02% or less, and the multilayer film is a transparent plastic Functionality characterized in that it is directly formed on the surface of the material and the multilayer film has a Vickers hardness of 15 or more, and the multilayer film further comprises a portion exhibiting a low reflection function and a portion exhibiting a conductive function. Plastic parts. 4. The functional plastic member according to claim 3, wherein a layer existing at a boundary between a portion exhibiting a low reflection function and a portion exhibiting a conductive function among layers constituting the multilayer film is a part of the low reflection film. And a functional plastic member which is a part of a conductive film. 5. The functional plastic member according to claim 1, wherein the low-reflection film or the transparent conductive film uses an RF magnetron sputtering apparatus, and is disposed on the side facing the transparent plastic material in the vicinity of the magnetron cathode. A functional plastic member formed by generating an ECR (electron cyclotron resonance) plasma on each side facing a magnetron cathode in the vicinity of a plastic material.

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