JP2009145899A - Near-infrared absorption filter and winding body thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a near infrared-ray absorbing filter, having a near-infrared ray absorption function that can reduce the transmission rate of the near-infrared ray, with a wavelength range of 850 to 1,100 nm, and to provide the winding body of the filter. <P>SOLUTION: The near infrared ray absorption filter includes a substrate; a film arranged on the main face side of the substrate; a protective film arranged on the main face of the film; and a near-infrared ray absorbing layer which is arranged on the side opposite to the main face side of the substrate on which the film is arranged, wherein the surface roughness Ra of the main face of the protective film on the side, opposite to the side at which the film is located is 0.01 μm or larger and 0.054 μm or smaller, and the winding body is manufactured by using the near-infrared ray absorbing filter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an antireflection film, and more specifically, an antireflection film that is easy to produce, has a low reflectance in the visible light wavelength region, and also has a near-infrared absorbing function, its wound body, and its wound body It is related with the manufacturing method.

  In recent years, development of high-definition and large-screen displays typified by plasma display panels has been rapidly progressing. Conventionally, in order to prevent reflection of external light on these display screens, a single layer of a thin film made of a low refractive index material, or a multilayer film combining a thin film made of a low refractive index material and a thin film made of a high refractive index material The method of obtaining the antireflection performance by arranging on the surface of the display screen is employed.

  In addition, in the plasma display panel, unnecessary near infrared rays are emitted when plasma discharge occurs, which adversely affects peripheral electronic devices, and in particular causes malfunctions of remote controls such as televisions and air conditioners. For this reason, the film containing a near-infrared absorber respond | corresponds by sticking on the front plate of a plasma display panel. In particular, recently, for the purpose of reducing the cost by improving the adhesion of each film and simplifying the process, there has been proposed a film that integrates each function (see, for example, Patent Document 1 and Patent Document 2).

  That is, in Patent Document 1, an antireflection layer is formed by forming an antireflection layer on one surface of a transparent resin film and laminating an adhesive layer containing a near infrared absorber on the other surface of the transparent resin film. A functional film is described.

Japanese Patent Laid-Open No. 10-156991 Japanese Patent Laid-Open No. 11-295506

  Usually, in the process of producing an antireflection film, it is essential to laminate a protective film in order to prevent the antireflection film formed on the surface of the transparent resin film substrate from being stained or damaged. However, when the antireflection film laminated with this protective film is wound into a roll to produce a wound body, the back surface of the protective film (the surface of the protective film opposite to the side where the antireflection film is located) If the surface roughness of the film is too small, the slip between the antireflection films deteriorates, and there is a problem in that winding failure occurs.

  In particular, when the near-infrared absorbing layer is formed on the surface of the substrate opposite to the side where the antireflection film is located, if the surface roughness of the back surface of the protective film is too small, the protective film and the near-infrared absorbing layer When the surface roughness of the back surface of the protective film is too large, the surface roughness of the protective film is transferred to the near infrared absorption layer.

  The present invention includes a base material, a film disposed on one main surface side of the base material, a protective film disposed on the main surface of the film, and a main surface of the base material on which the film is disposed. A near-infrared absorbing filter including a near-infrared absorbing layer disposed on the side opposite to the side, wherein the surface roughness Ra of the main surface of the protective film on the side opposite to the side on which the film is located is 0. Provided is a near-infrared absorption filter having a thickness of 01 μm or more and 0.054 μm or less.

  Moreover, this invention provides the wound body of the near-infrared absorption filter characterized by the above-mentioned near-infrared absorption filter being wound.

  INDUSTRIAL APPLICABILITY The present invention can provide an antireflection film that is easy to manufacture, has a low reflectance in the visible light wavelength region, and also has a near-infrared absorbing function and a wound body thereof.

  Moreover, this invention can provide the manufacturing method which can manufacture the wound body of an antireflection film stably, without reducing the characteristic of an antireflection film, and especially without reducing the quality of a near-infrared absorption layer.

It is sectional drawing which shows an example of the antireflection film of this invention. It is a side view which shows an example of the wound body of the antireflection film of this invention.

  First, an embodiment of the antireflection film of the present invention will be described. An example of the antireflection film of the present invention includes a base material, an antireflection film disposed on one main surface side of the base material, and a protective film disposed on the main surface of the antireflection film, The surface roughness Ra of the main surface (back surface) of the protective film on the side opposite to the side where the antireflection film is located is 0.01 μm or more and 1.0 μm or less.

  By using a protective film with a surface roughness Ra in the above range, the slip between the front and back surfaces of the antireflection film becomes moderate, and even when the antireflection film is wound, the winding failure and the characteristics of the antireflection film do not deteriorate. . In particular, when a near-infrared absorbing layer to be described later is formed on the surface of the substrate opposite to the side where the antireflection film is located, the surface roughness Ra on the back surface of the protective film is less than 0.01 μm. When the surface roughness Ra of the back surface of the protective film exceeds 1.0 μm, the surface roughness of the protective film is reduced to the near infrared absorbing layer. The properties of the near-infrared absorbing layer deteriorate due to the transition.

  The total light transmittance of the protective film is preferably 80% or more and 95% or less. When the total light transmittance of the protective film is less than 80%, it is difficult to inspect the application state of the antireflection film, and when it exceeds 95%, it is difficult to make the surface roughness Ra of the protective film 0.01 μm or more.

  Moreover, it is preferable to further arrange | position the near-infrared absorption layer on the opposite side to the main surface side of the said base material in which the said antireflection film is arrange | positioned. More specifically, by arranging the near infrared absorption layer, the spectral transmittance is preferably 0.1% to 20% in the entire region having a wavelength of 850 nm to 1100 nm, and particularly in the entire region of 900 nm to 1100 nm. The spectral transmittance is more preferably 0.1% to 10%. As a result, unnecessary near-infrared emission can be prevented. In particular, by attaching the antireflection film of the present embodiment to the front panel of the plasma display panel, unnecessary near-infrared emission is prevented and adversely affects peripheral electronic devices. No longer give.

  Moreover, it is preferable that an ultraviolet absorber is further included in any part between the near-infrared absorbing layer and the antireflection film. Thereby, deterioration of the near-infrared absorption layer by external light, such as sunlight, can be prevented. It is advantageous in production that the ultraviolet absorber is contained in the substrate.

  The antireflection film is preferably formed of a middle refractive index layer, a high refractive index layer, and a low refractive index layer in this order from the substrate side. Thereby, the reflectance in the visible light wavelength region can be reduced.

  Moreover, it is preferable to further form a hard coat layer between the base material and the antireflection film. Thereby, more excellent scratch resistance can be imparted.

  Next, an embodiment of the wound body of the antireflection film of the present invention will be described. An example of the roll of the antireflection film of the present invention is characterized in that the antireflection film described above is wound. By using the antireflection film as a wound body, it is easy to handle and carry the antireflection film having a low reflectance in the visible light wavelength region and also having a near infrared absorption function.

  Then, embodiment of the manufacturing method of the winding body of the antireflection film of this invention is described. An example of the manufacturing method of the roll of the antireflection film of the present invention includes a step of disposing an antireflection film on one main surface side of the substrate and a step of disposing a protective film on the main surface of the antireflection film. And a step of winding the substrate on which the protective film is disposed, and the surface roughness Ra of the main surface (back surface) of the protective film on the side opposite to the side on which the antireflection film is located is 0.01 μm. It is characterized by being 1.0 μm or more.

  By using a protective film having a surface roughness Ra in the above range, slippage between the front and back surfaces of the antireflection film becomes moderate, and winding up and the properties of the antireflection film do not deteriorate when the antireflection film is wound. When the surface roughness Ra is less than 0.01 μm, the slip between the front and back surfaces of the antireflection film is deteriorated and winding failure occurs. When the surface roughness Ra exceeds 1.0 μm, the protective film is not disposed. The surface roughness of the protective film is transferred to the surface of the substrate, and the properties of the antireflection film are deteriorated.

  In particular, when a near-infrared absorbing layer to be described later is formed on the surface of the substrate opposite to the side where the antireflection film is located, the surface roughness Ra on the back surface of the protective film is less than 0.01 μm. When the surface roughness Ra of the back surface of the protective film exceeds 1.0 μm, the surface roughness of the protective film is transferred to the near infrared absorbing layer. And the characteristic of a near-infrared absorption layer falls.

  The total light transmittance of the protective film is preferably 80% or more and 95% or less. When the total light transmittance of the protective film is less than 80%, it is difficult to inspect the application state of the antireflection film, and when it exceeds 95%, it is difficult to make the surface roughness Ra of the protective film 0.01 μm or more.

  Moreover, in the manufacturing method of this embodiment, it is preferable to further include the process of arrange | positioning a near-infrared absorption layer on the opposite side to the main surface side of the said base material in which the said antireflection film is arrange | positioned. Thereby, a near-infrared absorption function can be provided to an antireflection film.

  Moreover, in the manufacturing method of this embodiment, it is preferable to further include the process of arrange | positioning a ultraviolet absorber in any part between the said near-infrared absorption layer and the said antireflection film. Thereby, deterioration of the near-infrared absorption layer by external light, such as sunlight, can be prevented. It is advantageous in production that the ultraviolet absorber is contained in the substrate.

  The antireflection film is preferably formed of a middle refractive index layer, a high refractive index layer, and a low refractive index layer in this order from the substrate side. Thereby, the reflectance in the visible light wavelength region can be reduced.

  Moreover, in the manufacturing method of this embodiment, it is preferable to further include the process of arrange | positioning a hard-coat layer between the said base material and the said antireflection film. Thereby, more excellent scratch resistance can be imparted.

  Next, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing an example of the antireflection film of the present invention. The antireflection film of the present embodiment is an antireflection film comprising a base material 1, a hard coat layer 2 formed on one main surface of the base material 1, and three layers formed on the hard coat layer 2. 3, a protective film 4 disposed on the antireflection film 3, and a near infrared absorption layer 5 formed on the other main surface of the substrate 1. Moreover, the surface roughness Ra of the back surface 4a of the protective film 4 on the side opposite to the side in contact with the antireflection film 3 is set to 0.01 μm or more and 1.0 μm or less. Further, the antireflection film 3 is formed of a middle refractive index layer 3a, a high refractive index layer 3b, and a low refractive index layer 3c in this order from the substrate 1 side.

  The material of the base material 1 is not particularly limited as long as it is a light-transmitting material. For example, a resin such as a saturated polyester resin, a polycarbonate resin, a polyacrylate resin, an alicyclic polyolefin resin, a polystyrene resin, a polyvinyl chloride resin, or a polyvinyl acetate resin is formed into a film or sheet. What was processed can be used. Examples of the processing method into a film or sheet include extrusion molding, calendar molding, compression molding, injection molding, and a method in which the above resin is dissolved in a solvent and cast. The thickness of the substrate 1 is preferably about 10 μm to 500 μm. In addition, additives, such as antioxidant, a flame retardant, a heat-resistant agent, a ultraviolet absorber, a slipping agent, and an antistatic agent, may be added to the resin.

  The material of the hard coat layer 2 is not particularly limited as long as it is a material having high hardness and translucency. For example, thermosetting resin compositions such as urethane, melamine, and epoxy, or radiation curable resin compositions containing polyfunctional or monofunctional acrylate monomers, oligomers, photopolymerization initiators, and various additives However, a radiation curable resin composition having a particularly high surface hardness is preferable. Furthermore, by adding inorganic fine particles to the resin, higher surface hardness can be obtained and shrinkage due to curing of the resin can be alleviated. As the material of the inorganic fine particles, for example, silicon dioxide (silica), tin-doped indium oxide, antimony-doped tin oxide, zirconium oxide, or the like can be used.

  The method for forming the hard coat layer 2 on the substrate 1 is not particularly limited, and a coating method such as roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating or gravure printing, screen printing. Further, it can be formed by a printing method such as offset printing or inkjet printing. The thickness of the hard coat layer 2 is preferably 1 μm to 10 μm, and more preferably 2 μm to 7 μm.

The material of the medium refractive index layer 3a is not particularly limited as long as it has a light transmitting property with a refractive index _nm of 1.55 to 1.65, more preferably 1.57 to 1.63. For example, a coating composition in which inorganic fine particles having a high refractive index are uniformly dispersed in a crosslinkable organic component such as a thermosetting resin composition or a radiation curable resin composition is preferably used. Examples of the inorganic fine particles include fine particles of titanium oxide, tin oxide, indium oxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), zirconium oxide, zinc oxide, cerium oxide, and the like. Among them, it is particularly preferable to use ITO fine particles or ATO fine particles having high conductivity because the effect of preventing charging of the film can be obtained.

The method for forming the middle refractive index layer 3a on the hard coat layer 2 is not particularly limited, and can be formed by the various coating methods and printing methods described above. Refractive index n _m of the intermediate refractive index layer 3a and a thickness product of the d _m n _m d _m (optical thickness) is preferably from 100 nm to 150 nm, 110Nm～140nm is more preferable.

The material of the high refractive index layer 3b is not particularly limited as long as it is a material having a refractive index n _h of 1.75 to 1.85, more preferably 1.76 to 1.84 and translucency. For example, a coating composition in which titanium oxide fine particles, which are inorganic fine particles having the highest refractive index, are uniformly dispersed in a crosslinkable organic component such as a thermosetting resin composition or a radiation curable resin composition is preferably used. . The high refractive index layer 3b is formed as a film in which this coating composition is firmly crosslinked. Further, among the titanium oxide fine particles, those having an anatase structure have a photocatalytic action, and there is a problem that organic substances such as a resin component and a substrate constituting the coating film are decomposed by irradiation with ultraviolet rays. Therefore, titanium oxide fine particles having a rutile structure having a weak photocatalytic action and a high refractive index are preferably used. The amount of the titanium oxide fine particles is preferably 50% by weight to 65% by weight with respect to the total weight of the high refractive index layer 3b after curing.

There is no restriction | limiting in particular about the method of forming the high refractive index layer 3b on the middle refractive index layer 3a, It can form by the various coating methods and printing methods mentioned above. High refractive index n _h of the refractive index layers 3b and its the thickness d _h product n _h d _h (optical thickness) is preferably 210nm~260nm, 220nm~250nm is more preferable.

  In addition, an organic component having a refractive index in the range of 1.60 to 1.80, more preferably 1.65 to 1.75 may be included in a part of the organic component in the high refractive index layer 3b. preferable. Thereby, even if it reduces the quantity of the titanium oxide microparticles | fine-particles in the high refractive index layer 3b, a refractive index can be raised. Further, by reducing the amount of the titanium oxide fine particles, it is possible to prevent a decrease in the crosslinkability of the organic component in the high refractive index layer 3b, and the curing of the organic component (resin) is promoted, so that the antireflection film is scratch resistant. Will improve. If the refractive index of the organic component is less than 1.60, the effect of reducing the amount of titanium oxide fine particles in the high refractive index layer 3b is insufficient, and if it exceeds 1.80, the yellowishness of reflected light tends to increase. It is not preferable. Examples of the high refractive index organic material that can be an organic component having a refractive index in the range of 1.60 to 1.80 include organic compounds containing an aromatic ring, sulfur, bromine, and the like, such as diphenyl sulfide and its derivatives. Etc. can be used.

The material of the low refractive index layer 3c is not particularly limited as long as it is a material having a refractive index n ₁ of 1.35 to 1.45, more preferably 1.35 to 1.43 and translucency. For example, fluorine or silicone organic compounds, inorganic fine particles such as silica and magnesium fluoride, and the like are uniformly dispersed in a crosslinkable organic component such as a thermosetting resin composition or a radiation curable resin composition. A coating composition is preferably used. In particular, when an ultraviolet curable resin composition is used among the radiation curable resin compositions, in order to prevent polymerization inhibition due to oxygen, the oxygen concentration is about 1000 ppm or less by purging with an inert gas such as nitrogen. It is preferable to carry out ultraviolet irradiation under.

There is no restriction | limiting in particular about the method of forming the low-refractive-index layer 3c on the high-refractive-index layer 3b, It can form by the various coating methods and printing methods mentioned above. The product n _l d _l (optical thickness) of the refractive index n _l and the thickness d _l of the low refractive index layer 3c is preferably 120 nm to 150 nm, more preferably 120 nm to 140 nm.

  The material of the protective film 4 will not be restrict | limited especially if it is a material which has translucency. For example, polyethylene terephthalate, polyethylene naphthalate, polyurethane, polycarbonate, polystyrene, polypropylene, polyethylene and the like can be used. The surface roughness Ra of the back surface 4a needs to be set to 0.01 μm or more and 1.0 μm or less. As a method for setting the surface roughness Ra of the back surface 4a within this range, a method of containing ultrafine particles in the inside or the surface of the film is usually used, and the surface roughness of the film is adjusted by adjusting the particle size and content of the ultrafine particles. Ra can be controlled.

  Although there is no restriction | limiting in particular about the method of arrange | positioning the protective film 4 on the low-refractive-index layer 3c, Usually, the protective film 4 is provided in the state affixed on the separator via the adhesive, and the above-mentioned while peeling this separator It is laminated on the low refractive index layer 3c. Moreover, 5 micrometers-200 micrometers are preferable, and, as for the thickness of the protective film 4, 10 micrometers-100 micrometers are more preferable.

  The material of the near-infrared absorbing layer 5 is not particularly limited as long as it is a light-transmitting material that absorbs near infrared rays. Usually, a resin in which a compound that absorbs near infrared rays is dispersed is used. As the compound that absorbs near infrared rays, an organic dye having a maximum absorption wavelength in the near infrared region is preferable, for example, aminium, azo, azine, anthraquinone, indigoid, oxazine, quinophthalonine, squalium, Organic dyes such as stilbene, triphenylmethane, naphthoquinone, diimonium, phthalocyanine, cyanine, and polymethine can be used.

  As the resin, acrylic resin, polyurethane, polyvinyl chloride, epoxy resin, polyvinyl acetate, polystyrene, cellulose, polybutyral, polyester, etc. can be used, and a polymer blend in which two or more of these resins are blended. Can also be used.

  The near-infrared absorbing layer 5 preferably contains a material having a maximum absorption wavelength in a wavelength region of 850 nm to 1100 nm. When the near-infrared absorbing layer 5 contains the above compound, it is possible to reduce the near-infrared transmittance in the wavelength region 850 nm to 1100 nm without greatly reducing the visible light transmittance in the wavelength range of 400 nm to 850 nm. . As the material having the maximum absorption wavelength in the wavelength region of 850 nm to 1100 nm, the above organic dyes can be used alone or in combination of two or more. Thereby, the antireflection film of this embodiment can be suitably used also as a near-infrared absorption filter such as a plasma display panel.

  A compound that cuts the neon emission line spectrum (orange) of the plasma display panel can be appropriately added to the near-infrared absorbing layer 5. Thereby, red color can be more vividly developed in the plasma display panel. As the compound that cuts off the neon emission line spectrum, an organic dye having a maximum absorption wavelength in a wavelength region of 580 nm to 620 nm can be used. For example, cyanine, azurenium, squalium, diphenylmethane, triphenylmethane, oxazine Organic dyes such as azine, thiopylium, viologen, azo, azo metal complex, azaporphyrin, bisazo, anthraquinone, and phthalocyanine can be used.

(Embodiment 2)
FIG. 2 is a side view showing an example of a wound body of the antireflection film of the present invention. The wound body 11 of this embodiment is obtained by winding the antireflection film 12 of Embodiment 1 around a core material 13. Thus, by using the antireflection film 12 of the first embodiment provided with the protective film having a surface roughness Ra of 0.01 μm or more and 1.0 μm or less on the back surface, between the protective film and the near-infrared absorbing layer. Sliding becomes appropriate, and winding-up failure does not occur when winding up the antireflection film 12, and the characteristics of the near-infrared absorbing layer do not deteriorate.

  Hereinafter, the present invention will be specifically described based on examples. The present invention is not limited to the following examples.

Example 1
As a substrate, an ultraviolet-cutting polyethylene terephthalate (PET) film (“Lumirror QT58” manufactured by Toray) having a thickness of 100 μm and having both surfaces easily bonded was prepared. Next, 100 parts by weight of acrylate-based ultraviolet curable hard coating material containing silica ultrafine particles (“Desolite Z7501” manufactured by JSR) and 35 parts by weight of cyclohexanone are mixed and stirred to prepare a coating liquid. One surface was coated with a microgravure coater (manufactured by Yasui Seiki) and dried. Thereafter, ultraviolet rays were irradiated with an intensity of 300 mJ / cm ² to be cured, and a hard coat layer having a thickness of 4 μm was formed on one surface of the PET film.

Next, 100 parts by weight of an inorganic ultrafine particle-containing acrylate-based UV curable coating material (“Opstar TU4005” manufactured by JSR), 5 parts by weight of a polyfunctional acrylate (“DPHA” manufactured by Nippon Kayaku), and 200 parts by weight of cyclohexanone are mixed and stirred. Then, a coating solution was prepared, and this coating solution was coated on the hard coat layer using the microgravure coater and dried. Thereafter, ultraviolet rays were irradiated and cured at an intensity of 300 mJ / cm ² to form a medium refractive index layer (refractive index of 1.60) having a thickness of 72 nm on the surface of the hard coat layer.

Next, 30 parts by weight of ultrafine titanium oxide particles (“TTO55 (A)” manufactured by Ishihara Techno), 1 part by weight of dimethylaminoethyl methacrylate (“Light Ester DM” manufactured by Kyoeisha Chemical), phosphate group-containing methacrylate (manufactured by Nippon Kayaku) A composition obtained by mixing 4 parts by weight of “KAYAMER PM-21” and 65 parts by weight of cyclohexanone was dispersed by a sand grind mill to prepare a titanium oxide ultrafine particle dispersion, and an acrylate-based ultraviolet curable hard coat material ( A coating solution was prepared by blending and dispersing 15 parts by weight of Sanyo Chemical Industries "Sunrad H-601R") and 600 parts by weight of methyl isobutyl ketone. The coating liquid was coated on the medium refractive index layer using the microgravure coater and dried. Thereafter, ultraviolet rays are irradiated and cured at an intensity of 500 mJ / cm ² , and a high refractive index layer having a thickness of 130 nm is formed on the surface of the medium refractive index layer (the amount of titanium oxide fine particles in the solid content is 60% by weight, the refractive index. 1.80) was formed.

  Furthermore, 100 parts by weight of fluoropolymer-containing thermosetting low-refractive index antireflective material ("Opstar TT1006" manufactured by JSR) and 20 parts by weight of methyl isobutyl ketone are mixed and stirred to prepare a coating liquid. On the high refractive index layer, it coated and dried using the said micro gravure coater. Thereafter, heat treatment was performed at 120 ° C. for 6 minutes to form a low refractive index layer (refractive index of 1.41) having a thickness of 92 nm on the surface of the high refractive index layer.

  Next, a 25 μm-thick polyethylene terephthalate (PET) film (“Hitalex L-8010” manufactured by Hitachi Chemical Co., Ltd.) was laminated as a protective film on the low refractive index layer. The PET film was provided in a state of being attached to a separator via an adhesive, and was laminated on the low refractive index layer while peeling the separator. When the surface roughness Ra of the back surface of the protective film opposite to the side to which the adhesive was applied was measured with a stylus type surface roughness meter ("Dektak3ST" manufactured by Veeco), Ra was 0.042 µm. . Moreover, when the separator was peeled off, the total light transmittance of the protective film was measured using a spectrophotometer ("Ubest V-570 type" manufactured by JASCO Corporation), and it was 88%.

  Subsequently, 100 parts by weight of a polyester resin ("Elitel UE3690" manufactured by Unitika), 9.5 parts by weight of a near infrared absorbing dye ("Kayasorb IRG-022" manufactured by Nippon Kayaku), a near infrared absorbing dye ("EEX manufactured by Nippon Shokubai Co., Ltd.)" Color IR-12 ") 3.2 parts by weight, 2.2 parts by weight of neon light cut dye (" Art Cruz TY-100 "manufactured by Asahi Denka Kogyo), 370 parts by weight of cyclohexanone, 185 parts by weight of toluene, and 62 parts by weight of methyl ethyl ketone Were mixed and stirred to prepare a coating solution. This coating solution is coated on the other surface of the base material using the microgravure coater and dried to form a near-infrared absorbing layer having a thickness of 3 μm on the surface of the base material. A wound body of the antireflection film of Example 1 was produced.

(Example 2)
As a substrate, an ultraviolet-cutting polyethylene terephthalate (PET) film (“Lumirror QT58” manufactured by Toray) having a thickness of 100 μm and having both surfaces easily bonded was prepared. Next, 100 parts by weight of acrylate ultraviolet curable hard coating material containing ultrafine silica particles (“KAYANOVA FOP-5000” manufactured by Nippon Kayaku Co., Ltd.) and 40 parts by weight of cyclohexanone are mixed and stirred to prepare a coating solution. Was coated on one surface of the PET film using a micro gravure coater (manufactured by Yasui Seiki Co., Ltd.) and dried. Thereafter, ultraviolet rays were irradiated with an intensity of 300 mJ / cm ² to be cured, and a hard coat layer having a thickness of 4 μm was formed on one surface of the PET film.

  Next, a medium refractive index layer (refractive index 1.60) was formed on the hard coat layer in the same manner as in Example 1.

Subsequently, 30 parts by weight of titanium oxide ultrafine particles (“TTO55 (B)” manufactured by Ishihara Techno), 1 part by weight of dimethylaminoethyl methacrylate (“Light Ester DM” manufactured by Kyoeisha Chemical), phosphate group-containing methacrylate (manufactured by Nippon Kayaku) A composition obtained by mixing 4 parts by weight of “KAYAMER PM-21” and 65 parts by weight of cyclohexanone was dispersed by a sand grind mill to prepare a titanium oxide ultrafine particle dispersion, and an acrylate-based ultraviolet curable hard coat material ( A coating solution was prepared by blending and dispersing 15 parts by weight of Sanyo Chemical Industries "Sunrad H-601R") and 600 parts by weight of methyl isobutyl ketone. The coating liquid was coated on the medium refractive index layer using the microgravure coater and dried. Thereafter, ultraviolet rays are irradiated and cured at an intensity of 500 mJ / cm ² , and a high refractive index layer having a thickness of 128 nm is formed on the surface of the medium refractive index layer (the amount of titanium oxide fine particles in the solid content is 60% by weight, the refractive index. 1.81) was formed.

  Further, an alkoxysilane-based thermosetting low refractive index coating material (“LR-202” manufactured by Nissan Chemical Industries, Ltd.) is coated on the high refractive index layer using the microgravure coater and dried. A low refractive index layer (refractive index: 1.41) having a thickness of 95 nm was formed on the surface of the layer.

  Next, a 25 μm thick polyethylene terephthalate (PET) film (“Hitalex L-8310” manufactured by Hitachi Chemical Co., Ltd.) was laminated as a protective film on the low refractive index layer, and then heat treated at 70 ° C. for 72 hours. . The PET film was provided in a state of being attached to a separator via an adhesive, and was laminated on the low refractive index layer while peeling the separator. When the surface roughness Ra of the back surface of the protective film opposite to the side to which the adhesive was applied was measured with a stylus type surface roughness meter ("Dektak3ST" manufactured by Veeco), Ra was 0.054 µm. . Further, the total light transmittance of the protective film was measured using a spectrophotometer (“Ubest V-570 type” manufactured by JASCO Corporation) in a state where the separator was peeled, and it was 87%.

  Subsequently, a near-infrared absorbing layer was formed on the other surface of the base material in the same manner as in Example 1, and wound into a roll to produce a wound body of the antireflection film of Example 2.

(Comparative Example 1)
A wound body of the antireflection film of Comparative Example 1 was produced in the same manner as in Example 1 except that the surface roughness Ra of the back surface opposite to the side to which the adhesive of the protective film was applied was 1.2 μm. did.

(Comparative Example 2)
An attempt was made to produce a wound body of Comparative Example 2 in the same manner as in Example 1 except that the surface roughness Ra of the back surface opposite to the side to which the adhesive of the protective film was applied was 0.008 μm. However, winding failure occurred and the wound body could not be produced.

  Next, the following evaluation was performed using the antireflection film of the wound body obtained in Examples 1 and 2 and Comparative Example 1, and the results are shown in Table 1.

(1) Reflectance in the visible light wavelength region Using a spectrophotometer (“Ubest V-570 type” manufactured by JASCO Corporation), reflection on the antireflection film side of the antireflection film in the visible light wavelength region of 380 nm to 780 nm. The minimum reflectance in the region of 450 nm to 750 nm was measured.

(2) Surface state of near-infrared absorbing layer The surface state of the near-infrared absorbing layer of the antireflection film was visually determined. The judgment criteria were A: intact, B: slightly scratched, and C: numerous scratches.

(3) Spectral transmittance in the near infrared wavelength region Using the spectrophotometer, the maximum value of the spectral transmittance in the near infrared wavelength region of 850 nm to 1100 nm was measured.

  As is clear from Table 1, Example 1 and Example 2 have a better near-infrared absorbing layer surface state and smaller spectral transmittance in the near-infrared wavelength region of 850 nm to 1100 nm than Comparative Example 1. I understand that. In Comparative Example 1, since the surface roughness Ra of the back surface opposite to the side to which the adhesive of the protective film was applied was roughened to 1.2 μm, when the antireflection film was wound up to form a wound body In addition, the roughness of the back surface is transferred to the near-infrared absorbing layer. As a result, the appearance of the film is deteriorated due to surface unevenness, scratches, and the like, and the near-infrared transmittance is also increased.

  In Examples 1 and 2 and Comparative Example 1, it can be seen that the reflectance in the visible light wavelength region is low and the near-infrared absorption function is high.

  INDUSTRIAL APPLICABILITY The present invention can provide an antireflection film that is easy to produce, has a low reflectance in the visible light wavelength region, and also has a near-infrared absorbing function, and a wound body thereof. Moreover, this invention can provide the manufacturing method which can manufacture the winding body of an antireflection film stably, without reducing the characteristic of an antireflection film, and especially without reducing the characteristic of a near-infrared absorption layer. By using this antireflection film for a display front plate, it is possible to prevent external light from being reflected on a display screen such as a CRT, a liquid crystal display device, or a plasma display panel.

DESCRIPTION OF SYMBOLS 1 Base material 2 Hard-coat layer 3 Antireflection film 3a Middle refractive index layer 3b High refractive index layer 3c Low refractive index layer 4 Protective film 4a Back surface 5 Near-infrared absorption layer 11 Winding body 12 Antireflection film 13 Core material

Claims (2)

The substrate, the film disposed on one main surface side of the substrate, the protective film disposed on the main surface of the film, and the main surface side of the substrate on which the film is disposed are opposite A near infrared absorbing filter including a near infrared absorbing layer disposed on the side,
A near-infrared absorption filter, wherein the surface roughness Ra of the main surface of the protective film on the side opposite to the side on which the film is located is 0.01 μm or more and 0.054 μm or less.   A wound body of a near-infrared absorbing filter, wherein the near-infrared absorbing filter according to claim 1 is wound.

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