JP2005003725A - Optical protection thin film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the structure of an optical protection thin film having electrostatic prevention and antiglare functions, and to provide its manufacturing method. <P>SOLUTION: The optical protection thin film attains the electrostatic prevention and antiglare functions by successively forming a conductive thin film structure arranging two kinds of different resin thin films of a resin A and a resin B on a plastic substrate. The optical protection thin film attains conduction and antistatic functions by adding conductive particles of two kinds of particle diameter standards in the resin A, stretching particle diameter of the conductive particles of a comparatively large particle diameter standard between the total thickness of two resin thin film layers, and bringing at least a part of the conductive particles of the comparatively large particle diameter standard into contact with the uppermost surface of the thin film layer of the resin B or exposing at least a part of the conductive particles of the comparatively large particle diameter standard on the uppermost surface of the thin film layer of the resin B. Need for separately adding the conductive particles is eliminated by selecting a material providing good hardness after curing the resin B, and providing a hard protection function. Besides, the optical protection thin film provides the antiglare function by adding silicon oxide minute particles of a nano meter level in the neighborhood of the uppermost surface approaching the thin film layer of the resin B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical protective thin film having a kind of anti-static and anti-glare functions and a method of manufacturing the same, and more particularly, to a conductive substrate having a different particle size in a plastic substrate structure. In addition, the present invention relates to an optical protective thin film that achieves the above-described two functions by making microparticles and microparticles exist in the same structure, and a method for manufacturing the same.
[0002]
[Prior art]
A glass substrate or a light-transmitting plastic substrate is one of the basic elements indispensable for a flat display, and the light-transmitting plastic substrate is superior to the glass substrate in that it is light in weight and difficult to burst. However, the plastic substrate has the following disadvantages. That is, it is easy to generate static electricity and adsorb ash dust. In the case of a liquid crystal display, the structure of a typical simple tricks-driven liquid crystal flat display (SM-LCD) is as shown in FIG. 1, from the top to the bottom, a hard protective layer 13 (hard coating layer), a conductive layer 12 (conductive layer), protective film 11, polarizing plate 10, plastic substrate 30, column electrode 50, liquid crystal layer 80, row electrode 60, color filter 70, plastic substrate 40, polarizing plate 20, protective film 21, conductive layer 22, A hard protective layer 23 is provided. As shown in FIG. 1, the liquid crystal molecules are located between the column electrode 50 and the row electrode 60, and a driving voltage provided from the outside rotates the liquid crystal. However, the simple matrix drive type liquid crystal flat panel display (SM-LCD) has the problem that the crosstalk due to the increase in the number of scanning electrons and the charge accumulation of the upper and lower polarizing plates interfere with the electric field and the liquid crystal operation. . In the polarizing plate manufacturing process, an upper protective film and a release film are attached to the upper and lower surfaces, respectively. The purpose of the protective film is to protect the film surface of the polarizing plate and prevent the film surface from being damaged during the manufacturing process or transportation. The release film is used for protecting the adhesive before attaching the panel. When the protective film is peeled off, the film surface generates electrostatic accumulation due to friction, and the remaining static electricity can attract foreign substances. In addition, electrostatic accumulation also occurs during the removal of the release film during the manufacturing process, and foreign matter is sucked in. In addition, a deviation is generated in the alignment work when the panels are bonded together, which affects the process yield. For this reason, an anti-static anti-glare film (ASAG film) was generated. As described above, the antistatic antiglare thin film has a three-layer structure, that is, a hard protective layer 13, a conductive layer 12, and a protective film 11.
[0003]
In terms of antistatic technology, the conductive layer can also be formed by sputtering, the particles are relatively uniform, the degree of adhesion with the substrate is good, and the optical properties are also good. However, the equipment cost is high, it is necessary to carry out in a vacuum chamber, the hardware equipment is expensive, and it is difficult to carry out the work in the vacuum cavity of the raw resin film. In addition, as a method for forming a conductive layer by a wet coating method, a two-layer coating method (Patent Document 1) by Dai Nippon Printing has been submitted. According to this, a transparent protective film (hereinafter referred to as a plastic substrate) is formed. In addition, a transparent conductive layer and a hard protective layer are sequentially formed. Among them, the conductive layer contains conductive particles of antimony tin oxide (ATO) or indium tin oxide (ITO), and the surface resistance is 10 ⁸ Ω / □ or less, and the generation of static electricity is reduced. The increased conductive layer lowers the resistance of the substrate surface to about 10 ⁶ Ω / □, thereby preventing a large amount of static electricity. In consideration of translucency, the thickness can generally be about 5 μm. However, the hardness of the conductive layer is poor, and it is easy to drop off due to a collision. Therefore, it is necessary to apply a cured resin thereon to strengthen it. Further, since the cured resin itself does not have conductivity, it is necessary to extend the conductivity by adding conductive metal particles to remove accumulated charges. However, the conductive metal particle price is high, and the coating cost and process difficulty are also high.
[0004]
The hard protective layer is a mixture of hardened resin and conductive metal particles coated onto the conductive layer to provide basic hardness requirements with the hardened resin, and the added conductive metal particles are between the coating surface and the conductive layer. It is used for current conduction. If the antiglare function of the thin film is to be increased, extra nanometer level fine particles are added to the hard protective layer, and the antiglare function is generated by the scattering phenomenon of the fine particles with respect to the light.
[0005]
[Problems to be solved by the invention]
The present invention provides an optical protective thin film structure having an anti-glare and anti-glare function in response to the demand for a plastic substrate, and solves the above-mentioned problems of the prior art.
[0006]
The main object of the present invention is to provide a method for producing a kind of optical protective thin film, which has an antistatic function by adding conductive particles when a conductive layer is formed on a plastic substrate. It is the method of providing.
[0007]
Another object of the present invention is to provide a kind of method for producing an optical protective thin film, which is to form an antiglare layer by adding fine particles to the upper layer of the conductive layer when the conductive layer is formed on the plastic substrate. Is a way to achieve the function.
[0008]
Another object of the present invention is to provide a kind of optical protective thin film structure, which is an optical protective thin film having good structural hardness and high adhesion to a plastic substrate.
[0009]
[Means for Solving the Problems]
The invention of claim 1 is a method of manufacturing an optical protective thin film,
(A) A substrate, a resin A, and a resin B are prepared, and at least two different size standard conductive particles in the resin A, that is, a relatively large particle size standard conductive particle and a relatively small particle size standard conductive particle Adding a process,
(B) Resin A is coated on the substrate and cured to form a cured resin A thin film on the substrate, and the thickness of the cured resin A thin film is a conductive material having a relatively large particle size standard. A process that is smaller than the particle size of the particles and larger than the particle size of the conductive particles of the relatively small particle size standard,
(C) The resin B is coated on the resin A thin film and cured, and the cured resin B thin film is formed on the resin A thin film, and at least in the above-mentioned conductive particles having a relatively large particle size standard A process in which the upper edges of some of the relatively large particle size conductive particles are in contact with the upper surface of the cured resin B thin film or exposed from the upper surface to be in contact with the external environment;
An optical protective thin film manufacturing method characterized by comprising the above steps.
According to a second aspect of the present invention, in the method for producing an optical protective thin film according to the first aspect, the conductive particles having a relatively large particle size standard in the step (a) have a particle size of 0.5 to 7 μm, which is relatively small. The particle size of the conductive particles of the particle size standard is 0.1 to 0.5 μm, and these conductive particles are either antimony tin oxide (ATO) or indium tin oxide (ITO), This is a method for manufacturing an optical protective thin film.
According to a third aspect of the present invention, in the method for producing an optical protective thin film according to the first aspect, fine particles formed of silicon dioxide and having a particle diameter of 0.1 to 1 μm are added to the resin B, and the fine particles are added to the resin. The method of manufacturing an optical protective thin film is characterized by being distributed at positions approaching the upper surface of the B thin film.
The invention of claim 4 is the optical protective thin film,
A substrate,
Compared to the particle size of conductive particles having a relatively large particle size standard and conductive particles having a relatively small particle size standard formed on the substrate and having a relatively small particle size standard, and having a relatively small thickness A resin A thin film that is between the particle sizes of conductive particles having a large particle size standard;
A resin B thin film formed on the resin A thin film and contacting the upper surface of at least a part of the conductive particles having a relatively large particle size standard with the upper surface or being exposed from the upper surface;
An optical protective thin film characterized by comprising:
The invention according to claim 5 is the optical protective thin film according to claim 4, wherein the conductive particles are either antimony tin oxide (ATO) or indium tin oxide (ITO), and the conductive particles having a relatively large particle size standard The optical protective thin film is characterized in that the particle size of the conductive particles having a relatively small particle size standard is about 0.5 μm.
According to a sixth aspect of the present invention, in the optical protective thin film according to the fourth aspect of the present invention, the resin B thin film contains silicon dioxide fine particles having a particle size of 0.1 to 1.0 μm, and the fine particles are the resin B thin film. The optical protective thin film is characterized in that it is distributed at a position approaching the upper surface.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, a plastic substrate which is a cellulose triacetate film or a polyester film is provided, and then a conductive layer is formed on the plastic substrate. This conductive layer has a two-layer resin thin film structure formed using two different types of resins. That is, first, the conductive particles are mixed in the resin A to improve the conductive effect of the resin A. There are two types of particle size standards for the conductive particles. Resin A containing conductive particles is coated on the substrate by a wet coating method. Subsequently, most of the alcohols in the resin A are evaporated in the thermosetting step to fix the resin A, and the thickness of the resin A after the thermosetting is larger than the particle size of the conductive particles having a relatively large particle size standard. It shall be small. Further, the structure is strengthened by polymerizing the polymer in the resin A by heat curing or ultraviolet curing. Furthermore, the resin B having a good hardness is provided, and silicon dioxide having a small particle size is added to the resin B to serve to achieve an antiglare function due to the fine particles. The resin B containing fine particles is formed on the resin A by a wet coating method, and the gaps between the conductive particles are filled. Subsequently, the resin A is reinforced by a thermosetting process and a process such as thermosetting or ultraviolet curing. At this time, since the conductive particles having a relatively large particle size standard have a relatively large particle size, the upper edges of some of the relatively large particle size standard conductive particles are in contact with or exposed to the outside of the upper surface of the resin B. Thereby, it is possible to prevent electric charges from accumulating in the resin B, thereby achieving an antistatic function. Thus, an optical protective thin film having antistatic and antiglare functions is completed.
[0011]
【Example】
In the present invention, at least two kinds of conductive particles having different particle size specifications, that is, conductive particles having a relatively large particle size specification and conductive particles having a relatively small particle size specification are added to the resin A constituting the conductive layer. And provide anti-static function. Among these, the thickness of the cured resin A thin film is larger than the particle size of the conductive particles having the relatively small particle size specification and smaller than the particle size of the conductive particles having the relatively large particle size specification. Resin B is composed of a material having high hardness, which is coated on the resin A thin film to form a hard protective layer, and the upper edge of at least a part of the conductive particles having the relatively large particle size standard is cured. The resin B is in contact with the upper surface of the thin film or exposed to contact with the outside environment. Thereby, there is no need to add conductive metal particles to the resin B, the charge in the resin A thin film can be released to the outside, and the accumulation of the charge in the resin B can be prevented, thereby preventing the static electricity. The function is achieved, and the manufacturing process is simplified and the manufacturing cost is reduced.
[0012]
In order to explain the emphasis of the invention of the present invention, the present invention will be described by taking the production of a protective film for a flat display as an example and in combination with the drawings.
As shown in FIG. 2, the plastic substrate 100 is composed of cellulose, diacetate, triacetate, cellulose acetate butyrate, polyester, polyamide, Polyimide, polyethersulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, and polyacetal. Teruketon (polyether ketone), methyl polymethacrylate (methyl polymethacrylate), methacrylic resin (polymethyl methacrylate; PMMA), polycarbonate (poly carbonate), may be selected from polyurethane (the POLYURETHANE). Among them, preferred substrates are cellulose triacetate (TAC) and polyethylene (polyethylene). The TAC or PET substrate provided in this embodiment is a substrate material often used in the industry, and manufacturers such as Fuji and Konica provide this type of substrate.
[0013]
Subsequently, the emphasis of the present invention will be described. A conductive layer 200 is formed on the plastic substrate 100. The conductive layer 200 substantially has a two-layer structure including a resin A thin film layer that includes conductive particles and provides a good conductive layer, and a resin B thin film layer that is a relatively hard and hard protective layer. The formation of the conductive layer 200 is divided into two steps. That is, the conductive particles 220 and the resin A are first deposited or coated on the substrate 100, and then the resin B and the fine particles 230 are formed thereon. The detailed implementation process is as follows. As shown in FIG. 3, first, the conductive particles 220 are mixed in the resin A, and the resin A is 1-butanol, ethanol, ethyl acetate (EAC), hexane (Hexane). , Isopropanol (IPA) (80%) and some acrylic resins, and the solid content is 5-25%. The weight percentage of the conductive particles 220 in the resin A is between 5 and 30%, and there are two types of particle diameters of the conductive particles 220. ˜7 μm) and conductive particles having a relatively small particle size standard (particle size between 0.1 and 0.5 μm). The content of conductive particles having a relatively large particle size with a particle size of 0.5 to 7 μm is 0.5 to 10% by weight of the entire conductive particles 220. The content of conductive particles having a relatively small particle size standard with a particle size of 0.5 or less is 90 to 99.5% by weight of the entire conductive particles 220. The material of the conductive particles 220 is composed of antimony tin oxide (ATO) or indium tin oxide (ITO). Resin A including conductive particles 220 having at least two kinds of particle size standards is coated on substrate 100 by a wet coating method to form a thin film having a thickness of about 5 μm. Of these, spin coating, roll coating, gravure coating, bar coating, and slot die coating may be employed for wet coating. As can be seen from FIG. 3, the resin A used in the examples of the present invention becomes thin after the curing treatment steps such as thermal curing and ultraviolet irradiation, and all the conductive particles are completely removed. The thickness of the resin A after being cured is slightly larger than the particle size of the conductive particles having a relatively small particle size standard, but smaller than the particle size of the conductive particle having a relatively large particle size standard. The conductive particles having a relatively large particle size standard partially protrude outside the upper surface of the cured resin A (as shown in FIG. 2). The conductive particles 220 made of the ATO (or ITO) material are used as the conductive elements of the conductive layer in the traditional structure. In addition to providing ATO (or ITO) particles with the same particle size (about 0.1-0.5 μm) as in the traditional manufacturing process to provide conductivity and antistatic functions, ATO (or ITO) particles of conductive particles (0.5 to 7 μm) having a relatively large particle size standard are added. Under the assumption that the original conductivity is not affected, conductive particles are added to the resin B of the present invention by filling and straddling a relatively large particle size ATO between the thicknesses of the resin A and the resin B. In addition, it shall not affect the antistatic function. By this method, it is possible to prevent the disadvantage of charge accumulation due to addition of conductive metal particles to the hard protective layer, which is a known technique, thereby reducing the difficulty in the manufacturing process and reducing the manufacturing cost.
[0014]
Subsequently, a thermosetting process during the curing process is performed, and most of the alcohols in the resin A are evaporated in the thermosetting process to fix the resin A. The thermosetting temperature is between 50 and 95 ° C., and the thermosetting time is 0.5 to 5 minutes. The thermosetting temperature is determined by the solvent used for the resin A and is lower than the boiling point of the solvent, and the thermosetting process is performed. In this example, the solvent of the resin A is isopropanol, and the thermosetting temperature used is about 60 ° C. Subsequently, ultraviolet rays are used to cause the polymer in the resin A to undergo a cross-link polymerization reaction to strengthen the structure. At this time, the amount of ultraviolet energy supplied is between 150 and 1000 mJ / cm ² , and the thickness of the cured resin A is 0.5 to 2 μm.
[0015]
Subsequently, 1 to 3 wt% silicon dioxide or silicon oxide or
Silica) Nanometer-level microparticles 230 are added into resin B, and mixed and stirred by a mixer. The silicon dioxide microparticles 230 have a particle size of 0.1 to 1.0 μm. The main component in the resin B is an acrylic resin, and the solid content is 45 to 50%. After the curing process, the hard protective layer has a relatively high hardness. During the coating and curing process of the resin B, the silicon dioxide fine particles 230 gather upward near the upper surface of the resin B due to their buoyancy. Therefore, using the microparticles 230 (silica) in the vicinity of the upper surface of the outermost layer (resin B), after the light is incident, the incident light is scattered at different angles in an irregular manner due to the presence of the microparticles 230. Achieve anti-glare cure. Resin B containing fine particles 230 is coated between conductive particles 220 on resin A to a thickness of about 10 μm by a wet coating method, and gaps between all conductive particles 220 are filled. The fine particles 230 float near the surface of the resin B due to the buoyancy, and exhibit the antiglare function. Among them, the same or different coating method as that of the resin A can be used for the wet coating. Subsequently, a curing process is performed, and most of the solvent in the resin B is evaporated by a thermosetting process to fix the resin B. The thermosetting temperature is 50 to 95 ° C., and the thermosetting time is 0.5 to 5 min. Subsequently, ultraviolet rays are used to cause the polymer in the resin B to undergo a cross-link polymerization reaction to strengthen the structure. At this time, the amount of ultraviolet energy supplied is between 150 and 1000 mJ / cm ² , and the thickness of the resin A after curing is 4 to 5 μm.
[0016]
The conductive layer 200 thus formed has functions of hard protection, antistatic and antiglare. With the conductive particles 220, the resin layer 200 or the resin layer B has the electrostatic release function in the conductive layer 200, and the hardness of the resin B also sufficiently protects the conductive layer 200 and the substrate 100. Provides the function of a hard protective layer during the traditional process. The present invention can be applied to the surface optical film of a flat display (for example, LCD, PDA, PDP, notebook personal computer, CRT). Utilizing the anti-static and anti-glare functions of this optical thin film to meet the demand for materials of LCD panel manufacturers that require anti-static, reduce ash dust adsorption on flat displays and increase user comfort To do.
[0017]
【The invention's effect】
In summary, the present invention comprises at least two kinds of conductive particles having different particle size specifications in the resin A, of which the particle size of the relatively large particle size specification is larger than the thickness of the cured resin A thin film. Instead, the total thickness after curing of both the resin A and the resin B is set to be equal to or greater. As a result, the upper edge of at least a part of the conductive particles having a relatively large particle size standard is in contact with or exposed to the upper surface of the cured resin B thin film. The charge inside can be released to the outside, and the charge accumulation in the resin B can be prevented, thus achieving the antistatic function. As a result, a known technique (for example, Patent Document 1) solves the difficulty in the manufacturing process and the disadvantage of increasing the manufacturing cost due to the addition of conductive metal particles to the hard protective layer. Has achieved the functions of simplification and manufacturing cost reduction.
[0018]
The above description is not intended to limit the scope of the present invention, and any modification or alteration in detail that can be made based on the present invention shall fall within the scope of the present invention.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of a conventional simple matrix drive type liquid crystal flat display.
FIG. 2 is a sectional view of a manufacturing process structure of a plastic substrate in an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a manufacturing process structure for forming conductive particles in an example of the present invention.
FIG. 4 is a cross-sectional view of a manufacturing process structure for forming an antiglare function conductive layer in an example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Polarizing plate 11 Protective film 12 Conductive layer 13 Hard protective layer 20 Polarizing plate 21 Protective film 22 Conductive layer 23 Hard protective layer 30 Plastic substrate 40 Plastic substrate 50 Column electrode 60 Row electrode 70 Color filter 80 Liquid crystal layer 100 Plastic substrate 200 Conductive layer 220 conductive particles 230 microparticles A resin B resin

Claims (6)

In the method for producing an optical protective thin film,
(A) A substrate, a resin A, and a resin B are prepared, and at least two different size standard conductive particles in the resin A, that is, a relatively large particle size standard conductive particle and a relatively small particle size standard conductive particle Adding a process,
(B) Resin A is coated on the substrate and cured to form a cured resin A thin film on the substrate, and the thickness of the cured resin A thin film is a conductive material having a relatively large particle size standard. A process that is smaller than the particle size of the particles and larger than the particle size of the conductive particles of the relatively small particle size standard,
(C) The resin B is coated on the resin A thin film and cured, and the cured resin B thin film is formed on the resin A thin film, and at least in the above-mentioned conductive particles having a relatively large particle size standard A process in which the upper edges of some of the relatively large particle size conductive particles are in contact with the upper surface of the cured resin B thin film or exposed from the upper surface to be in contact with the external environment;
A method for producing an optical protective thin film comprising the steps described above. The method for producing an optical protective thin film according to claim 1, wherein the particle size of the conductive particles having a relatively large particle size standard in the step (a) is 0.5 to 7 µm, A method for producing an optical protective thin film, characterized in that the particle diameter is 0.1 to 0.5 μm, and these conductive particles are either antimony tin oxide (ATO) or indium tin oxide (ITO). 2. The method for producing an optical protective thin film according to claim 1, wherein fine particles formed of silicon dioxide and having a particle diameter of 0.1 to 1 [mu] m are added in the resin B, and the fine particles are brought close to the upper surface of the resin B thin film. A method for producing an optical protective thin film, characterized in that the optical protective thin film is distributed at a position to be distributed. In optical protective thin film,
A substrate,
Compared to the particle size of conductive particles having a relatively large particle size standard and conductive particles having a relatively small particle size standard formed on the substrate and having a relatively small particle size standard, and having a relatively small thickness A resin A thin film that is between the particle sizes of conductive particles having a large particle size standard;
A resin B thin film formed on the resin A thin film and contacting the upper surface of at least a part of the conductive particles having a relatively large particle size standard with the upper surface or being exposed from the upper surface;
An optical protective thin film characterized by comprising: 5. The optical protective thin film according to claim 4, wherein the conductive particles are either antimony tin oxide (ATO) or indium tin oxide (ITO), and the conductive particles having a relatively large particle size standard have a particle size of 0.5. An optical protective thin film characterized in that the particle size of conductive particles having a relatively small particle size is about 0.5 μm. 5. The optical protective thin film according to claim 4, wherein fine particles of silicon dioxide having a particle size of 0.1 to 1.0 [mu] m are contained in the resin B thin film, and the fine particles approach the upper surface of the resin B thin film. An optical protective thin film characterized by being distributed in

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