JP2008208310A - Easily adhesive film for optical use, optical sheet and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesion strength of an easily adhesive laminate film used in a display device such as a liquid crystal display. <P>SOLUTION: A support 11 made of polyester is biaxial stretched. On at least one side of the biaxially stretched support 11, a first easily adhesive layer 12 and a second easily adhesive layer 13 are successively formed, provided that the first easily adhesive layer 12 is closer to the support 11 and contains a first binder, and the second easily adhesive layer 13 contains a crosslinking agent and a second binder comprising an acrylic resin or a urethane resin. The thickness of the first easily adhesive layer 12 is 200-500 nm, and the thickness of the second easily adhesive layer 13 is 50-200 nm. By adjusting the thickness of the first easily adhesive layer 12 to 200-500 nm, stress can be dispersed in the thickness direction, even when the peeling force acts on the first and second easily adhesive layers 12 and 13. Thus, the resultant laminate film 10 does not cause cohesive failure and is excellent in adhesive strength. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optically easy-to-adhere film, an optical sheet such as a prism sheet, an antireflection sheet, a light diffusing sheet, an antiglare sheet, and a hard coat sheet, and a liquid crystal display, plasma display, organic EL The present invention relates to a display device such as a display or a CRT display.

  A laminated film made of a polymer and formed by laminating a plurality of layers is often used as an optical film because of advantages such as transparency and processability. Among these, polyester films, in particular, biaxially oriented polyester films, are excellent in transparency, dimensional stability, chemical resistance, and low hygroscopicity, and are therefore widely used as various optical film bases. For example, base films such as prism sheets, antireflection sheets, light diffusion sheets, and hard coat sheets used in liquid crystal displays, IR absorption sheets, electromagnetic wave shielding sheets, toning sheets, antireflection sheets, antiglare sheets used in plasma displays Use as a base film such as a sheet or a hard coat sheet can be mentioned.

The polyester film used as a base film is required to have excellent transparency, and excellent adhesion to a layer including a prism layer (hereinafter sometimes referred to as an upper layer) laminated on the polyester film ( Easy adhesion) is required. However, because the base film and the upper layer are made of different components, it is difficult to directly bond each other with sufficient strength. Therefore, generally, a method of forming a polyester film by providing a coating layer called an easy adhesion layer on a support made of polyester (referred to as a polyester support) is used. There has been proposed a polyester film provided with an easy adhesion layer formed by mixing polyester and urethane (for example, see Patent Document 1). Moreover, the polyester film with which the average thickness of the application layer was less than 20 nm on the polyester support body and the easily-adhesive application layer which has a crosslinked structure was formed is proposed (for example, refer patent document 2).
JP 2000-229395 A JP 2004-258174 A

  In patent document 1, the adhesiveness which was excellent with respect to both a support body and an upper layer is shown by mixing the polyester which is the same kind component as a polyester support body, and the urethane which shows the adhesiveness outstanding with respect to the upper layer. A laminated film can be obtained. Moreover, in patent document 2, the laminated film which shows the adhesiveness outstanding by the combination of a specific polyester binder and a crosslinking agent can be obtained by making a coating layer film thickness into less than 20 nm. However, in the conventional ones shown in these patent documents, for example, when the thickness of the upper layer is large, or when the laminated film is assembled as an optical sheet, the display device on which the film is mounted is placed in a high temperature or high humidity atmosphere for a long time. In such a case, the adhesiveness at the interface between the support and the coating layer or at the interface between the coating layer and the upper layer is lowered, and as a result, the adhesiveness between the laminated film and the upper layer is lowered. Have Therefore, it is desired to propose a laminated film that does not deteriorate the adhesiveness even when the thickness of the upper layer is large or when it is exposed to high temperature or high humidity for a long time.

  The present invention has been made in order to solve the above-mentioned problem, and easily adheres with sufficient adhesion to both the support and the upper layer even when the thickness of the upper layer is large or under high temperature and high humidity. It aims at proposing the laminated film which has a layer, and its manufacturing method. Moreover, it aims at providing the optical sheet and display apparatus which are excellent in an optical characteristic by using this laminated film.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has obtained the following knowledge and made the present invention. Conventionally, when layers having low adhesive strength are laminated, an undercoat layer is generally inserted between the base layer and the upper layer as described in Patent Document 2 to increase the adhesive strength between the two. However, there is a limit to the increase in adhesive strength by such an undercoat layer. So, when I changed the conditions of the undercoat layer and tried various peeling experiments between the base layer and the upper layer, it was said that peeling occurred in the undercoat layer due to cohesive failure in the undercoat layer rather than peeling at the interface. I found out. And for such cohesive failure in the undercoat layer, the undercoat layer should have a two-layer structure, and the thickness of the first easy-adhesion layer on the support side should be set to a thickness that does not cause condensation failure. Knowledge was obtained.

  Based on the above knowledge, the optical easy-adhesive film of the present invention is formed on a support made of polyester, at least one surface of the support, and a first easy-adhesive layer having a thickness of 200 nm to 500 nm, And a second easy-adhesion layer having a thickness of 50 nm to 200 nm.

  The first easy-adhesion layer has a binder containing a polyester resin, and the second easy-adhesion layer has a binder containing an acrylic resin or a polyurethane resin. The first easy-adhesion layer and the second easy-adhesion layer contain a carbodiimide-based crosslinking agent.

  The optical sheet of the present invention includes the optical easy-adhesive film and a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, and a hard coat layer formed on the second easy-adhesive layer of the optical easy-adhesive film. And an upper layer made of at least one of the above. Moreover, the display device of the present invention is characterized by having the optically easy-to-adhere film or the optical film.

  In the present invention, a laminated film can be obtained in which the easy adhesion to both the support and the upper layer does not deteriorate even when the upper layer is thick or placed in a high temperature or high humidity atmosphere for a long time. Then, by combining this laminated film with an upper layer such as a prism layer or an antireflection layer, an optical sheet excellent in optical characteristics and a display device can be obtained.

  The easy-adhesion layer has a first and second two-layer structure, and the thickness of the first easy-adhesion layer is 200 nm or more and 500 nm or less, so that when the peeling force acts on the laminated film, the thickness in the easy-adhesion layer increases. The stress is dispersed by this, and the peeling force does not concentrate on the interface by that amount, which seems to improve the adhesive strength. In this way, by changing the thickness of the easy-adhesion layer from the conventional idea of 100 nm or less to 200 nm or more and 500 nm or less, peeling within the easy-adhesion layer was suppressed, and the adhesive strength was significantly improved.

  Hereinafter, the present invention will be described in detail. The embodiment describes a preferred application example of the present invention, and does not limit the present invention.

  As shown in FIG. 1, the laminated film 10 of the present invention includes a support 11 made of polyester, and a first easy-adhesion layer 12 and a second easy-adhesion layer 13 that are provided in this order from the side closer to the support 11. In addition, the 1st and 2nd easily bonding layers 12 and 13 should just be provided in the at least one surface of the support body 11, and the surface is not specifically limited.

  As shown in FIG. 2, the upper layer 14 is formed on the second easy adhesion layer 13 of the laminated film 10. As the upper layer 14, there are a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, a hard coat layer, and the like, and at least one of these is formed to form the optical sheet 15. Examples of these optical sheets 15 include prism sheets, antireflection sheets, light diffusion sheets, hard coat sheets, plasma display IR absorption sheets, electromagnetic wave shield sheets, and toning sheets used in liquid crystal displays.

[Polyester support]
The support 11 of the present invention is a polyester base film made of polyester. As the polyester, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, or the like can be used, and polyethylene terephthalate is particularly preferable from the viewpoint of cost and mechanical strength. However, the polyester that can be used in the present invention is not particularly limited.

  The polyester of the present invention is preferably stretched in order to improve mechanical strength, and particularly preferably biaxially stretched. Although there is no restriction | limiting in particular in a draw ratio, 1.5-7 times are preferable, More preferably, it is about 2-5 times. In particular, biaxially stretched products that are stretched about 2 to 5 times in the vertical and horizontal directions are preferable. By setting the draw ratio of the support 11 to 1.5 times or more, sufficient mechanical strength can be obtained as compared with the case of less than 1.5 times. Further, by setting the draw ratio to 7 times or less, a uniform thickness can be obtained as compared with the case where the draw ratio exceeds 7 times.

  The thickness of the support 11 is 30 μm or more and 400 μm or less. More preferably, it is 35 μm or more and 350 μm or less. The thickness of the support 11 can be easily adjusted by controlling the draw ratio. Such a support 11 is lightweight and excellent in handleability while having transparency and various optical properties. The support 11 having a thickness of 30 μm or more is not too thin and is easy to handle. Further, the support 11 having a thickness of 400 μm or less has an appropriate thickness, which makes it easy to reduce the size and weight of the image display device, and does not cause an increase in manufacturing cost. The support 11 of the present invention may contain an ultraviolet absorber and an antioxidant. In particular, when used for an antireflection film for PDP, it is preferable to contain an ultraviolet absorber as described in JP-A-2006-212815.

[First easy-adhesion layer]
The first easy-adhesion layer 12 is a layer that is directly laminated on the support 11. The first easy-adhesion layer 12 must contain a binder, and preferably contains a carbodiimide-based crosslinking agent. The first easy-adhesion layer 12 may contain a matting agent, a surfactant, an antistatic agent, and the like as necessary.

  Although the detail of the carbodiimide type crosslinking agent used for the 1st easily bonding layer 12 is mentioned later, the addition amount is 1 mass% or more and 100 masses with respect to the binder (1st binder) of the 1st easily bonding layer 12. % Or less, more preferably in the range of 5% by mass or more and 50% by mass or less. By making the addition amount 1% by mass or more, the effect of suppressing the flaking off of the fine particles can be obtained as compared with the case where the addition amount is less than 1% by mass. Moreover, when the addition amount is 100% by mass or less, deterioration of the coated surface state of the first easy-adhesion layer 12 is suppressed as compared with the case where the amount exceeds 100% by mass.

  The first binder is not particularly limited, and polymers such as (a) acrylic resin, (b) polyurethane resin, (c) polyester resin, and (d) rubber-based resin can be preferably used.

  (A) Acrylic resin is a polymer containing acrylic acid, methacrylic acid and derivatives thereof as components. Specific examples include acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylamide, acrylonitrile, hydroxyl acrylate, and the like as main components, and monomers copolymerizable therewith (for example, styrene, And polymers obtained by copolymerization of divinylbenzene and the like.

  (B) The polyurethane resin is a general term for polymers having a urethane bond in the main chain, and is usually obtained by the reaction of polyisocyanate and polyol. Examples of the polyisocyanate include TDI, MDI, NDI, TODI, HDI, and IPDI. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, and hexanetriol. As the isocyanate of the present invention, a polymer obtained by subjecting a polyurethane polymer obtained by the reaction of polyisocyanate and polyol to chain extension treatment to increase the molecular weight can also be used. The polyisocyanate, polyol and chain extension treatment described above are described in, for example, “Polyurethane Resin Handbook” (edited by Keiji Iwata, Nikkan Kogyo Shimbun, published in 1987).

  (C) The polyester resin is a general term for polymers having an ester bond in the main chain, and is usually obtained by a reaction between a polycarboxylic acid and a polyol. Examples of the polycarboxylic acid include fumaric acid, itaconic acid, adipic acid, sebacic acid, terephthalic acid, and isophthalic acid. Examples of the polyol include those described above. The polyester resin and its raw materials are described, for example, in “Polyester Resin Handbook” (Eiichiro Takiyama, Nikkan Kogyo Shimbun, published in 1988).

  The (d) rubber-based resin in the present invention refers to a diene-based synthetic rubber among the synthetic rubbers. Specific examples include polybutadiene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-divinylbenzene copolymer, butadiene-acrylonitrile copolymer, and polychloroprene. The rubber-based resin is described in, for example, “Synthetic Rubber Handbook” (edited by Amane Kambara, published by Asakura Shoten Co., Ltd., 1967).

  In the present invention, it is particularly preferable to use a polyester resin as the first binder in order to improve the adhesion to the support 11 made of polyester.

  Moreover, as said 1st binder, said polymer may be melt | dissolved and used for an organic solvent, and an aqueous dispersion may be used. However, since the environmental load is small, it is preferable to perform aqueous coating using an aqueous dispersion. The aqueous dispersion is not particularly limited as long as a commercially available polymer may be used. Examples of those that can be preferably used in the present invention include Superflex 830, 460, 870, 420, 420 NS (trade name: No. 1). Polyurethane manufactured by Ichi Kogyo Seiyaku Co., Ltd.), Bondic 1370NS, 1320NS, Hydran APX-101H, AP-40 (F) (trade name: polyurethane manufactured by Dainippon Ink & Chemicals, Inc.), Jurimer ET325, ET410, SEK301 ( Brand name: Nippon Pure Chemicals Co., Ltd. Acrylic), Boncourt AN117, AN226 (Product name: Dainippon Ink Chemical Co., Ltd. acrylic), Luck Star DS616, DS807 (Brand name: Dainippon Ink Chemical Co., Ltd.) Styrene-butadiene rubber), Nippon LX110, LX2 6, LX426, LX433 (trade name: styrene-butadiene rubber manufactured by Nippon Zeon Co., Ltd.), Nippon LX513, LX1551, LX550, LX1571 (trade name: acrylonitrile-butadiene rubber manufactured by Nippon Zeon Co., Ltd.), Finetex ES650, ES2200 (Trade name: polyester manufactured by Dainippon Ink & Chemicals, Inc.), Bayronal MD1400, MD1480 (trade name: polyester manufactured by Toyobo Co., Ltd.), plus coat Z561, Z687 (trade name: polyester manufactured by Kyoyo Chemical Co., Ltd.) Etc.

  As the polymer used as the first binder, one type may be used alone, or two or more types may be mixed and used as necessary. The molecular weight of the polymer used as the first binder is not particularly limited, but it is preferable to use a polymer having a weight average molecular weight of about 3000 to 1000000. When the weight average molecular weight of the polymer is 3000 or more, there is no possibility that the strength of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 is insufficient as compared with the case of less than 3000. In addition, when the weight average molecular weight of the polymer is 1,000,000 or less, the ease of application due to the decrease in fluidity is not impaired as compared with the case where the weight average molecular weight exceeds 1,000,000. Deterioration of the surface state of the adhesive layer 13 is suppressed.

The first easy-adhesion layer 12 preferably contains fine particles mainly composed of any one of tin oxide, zirconium oxide, and titanium oxide for the purpose of controlling the refractive index. For example, the tin oxide is preferably tin (IV) oxide having a SnO ₂ composition. The use of tin oxide doped with antimony or the like is preferable because it has conductivity, and therefore the effect of reducing the surface resistivity of the laminated film and preventing impurities such as dust from adhering can be obtained. Specific examples of such antimony-doped tin oxide include commercially available FS-10D, SN-38F, SN-88F, SN-100F, TDL-S, and TDL-1 (all of which are Ishihara Sangyo ( Etc.), and the like can also be suitably used in the present invention.

The zirconium oxide has a composition of ZrO ₂ , and examples thereof include NZS-20A and NZS-30A (both manufactured by Nissan Chemical Co., Ltd.), and these can also be suitably used in the present invention. As titanium oxide, titanium (IV) oxide having a TiO ₂ composition is preferably used. Titanium oxide has a rutile type (tetragonal high-temperature type), anatase type (tetragonal low-temperature type), etc. depending on the difference in crystal structure, but is not particularly limited. Further, titanium oxide subjected to surface treatment may be used. Examples of titanium oxide that can be suitably used in the present invention include IT-S, IT-O, and IT-W (all manufactured by Idemitsu Kosan Co., Ltd.).

  The average particle size of the fine particles as described above is preferably 15 nm or more and 200 nm or less. The refractive index of the first easy-adhesion layer 12 containing such fine particles can be easily controlled. When fine particles having an average particle diameter of 200 nm or less are used, there is no possibility that the transparency of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 that can be visually confirmed is lowered or the light transmittance is lowered. . In addition, by using fine particles having an average particle size of 15 nm or more, it is possible to obtain them at a lower price than fine particles having a particle size of less than 15 nm, which is advantageous in terms of production cost. In addition, since fine particles having a size of 15 nm or more are used, there is less possibility that the particles become giant foreign matters due to aggregation of the fine particles compared to the case of using fine particles smaller than that, and the transparency is not lowered. In addition, the average particle diameter of the fine particles in the present invention refers to the particles obtained for any 50 fine particles when the diameter of a circle having the same area as the fine particles when the fine particles are photographed with a scanning electron microscope is used as the particle diameter. Mean diameter.

  Moreover, you may use various additives, such as a mat agent and surfactant other than the above, for the 1st easily bonding layer 12 according to a use. As the matting agent that can be used for the first easy-adhesion layer 12 of the present invention, either organic or inorganic fine particles can be used. For example, polymer fine particles such as polystyrene, polymethyl methacrylate, silicone resin, and benzoguanamine resin, and inorganic fine particles such as silica, calcium carbonate, magnesium oxide, and magnesium carbonate can be used. Among these, polystyrene, polymethyl methacrylate, and silica are preferable from the viewpoint of the effect of improving the slipperiness and cost.

The average particle size of the matting agent is preferably 0.3 μm or more and 12 μm or less, more preferably 0.5 μm or more and 9 μm or less. By setting the average particle size of the matting agent to 0.3 μm or more, better slipperiness can be obtained as compared with the case of less than 0.3 μm. Further, by setting the average particle size to 12 μm or less, there is no possibility that the display quality of the image display device is deteriorated as compared with the case of exceeding 12 μm. Further, the amount of the matting agent added varies depending on the average particle diameter, but it is excellent in the effect of improving the slipperiness and does not deteriorate the display quality of the image display device, so that it is 0.1 mg / m ² or more and 30 mg / m. It is preferably ² or less, more preferably 0.5 mg / m ² or more and 20 mg / m ² or less. By making the addition amount of the matting agent 0.1 mg / m ² or more, the effect of improving the slipping property can be obtained. Moreover, the fall of the display quality of an image display apparatus can be suppressed by setting it as 30 mg / m < ² > or less. The average particle size of the matting agent in the present invention is a value measured by the same method as the average particle size of the fine particles described above.

Examples of the surfactant that can be used for the first easy-adhesion layer 12 include known anionic, nonionic, and cationic surfactants. The surfactant is described in, for example, “Surfactant Handbook” (Nishi Ichiro, Imai Junichiro, Sho Kasai edited by Sangyo Kasho Co., Ltd., 1960). When a surfactant is used, the addition amount is preferably 0.1 mg / m ² or more and 30 mg / m ² or less, more preferably 0.2 mg / m ² or more and 10 mg / m ² or less. By the addition amount of the surfactant and 0.1 mg / m ² or more, the effect can be obtained with a surfactant as compared with the case of less than 0.1 mg / m ^2, the first adhesion layer 12, the second Occurrence of cissing in the easy-adhesion layer 13 is suppressed. Moreover, by making the addition amount 30 mg / m ² or less, it is possible to suppress deterioration of the surface states of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 as compared with the case where it exceeds 30 mg / m ^2. .

An antistatic agent can also be used for the first easy-adhesion layer 12. The type of the antistatic agent is not particularly limited. For example, an electron conductive polymer such as polyaniline and polypyrrole, an ion conductive polymer having a carboxyl group or a sulfonic acid group in the molecular chain, conductive fine particles, etc. Is mentioned. Among these, the conductive tin oxide fine particles described in JP-A-61-20033 can be preferably used from the viewpoints of conductivity and transparency. The addition amount of the antistatic agent is preferably adjusted so that the surface resistivity of the first easy-adhesion layer 12 measured in an atmosphere of 25 ° C. and 30% RH is 1 × 10 ⁵ Ω or more and 1 × 10 ¹³ Ω or less. . By making the surface resistance of the first easy-adhesive layer 12 and the second easy-adhesive layer 13 1 × 10 ⁵ Ω or more, avoid using a large amount of antistatic agent compared to the case of less than 1 × 10 ⁵ Ω. , A decrease in the transparency of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 is suppressed. Further, by setting the surface resistance to 1 × 10 ¹³ Ω or less, an antistatic effect can be secured as compared with the case where it exceeds 1 × 10 ¹³ Ω, and the first easy-adhesive layer 12 and the second easy-adhesive layer There is no possibility that impurities such as dust adhere to the surface of 13.

  The thickness of the first easy-adhesion layer 12 is 200 nm or more and 500 nm or less in order to develop easy adhesion to the support 11 and to ensure sufficient adhesive strength at the interface. More preferably, the thickness of the first easy-adhesion layer 12 is 250 nm or more and 400 nm or less. By setting the film thickness of the first easy-adhesion layer 12 to 200 nm or more, the adhesion between the support 11 and the upper layer 14 is improved as compared with the case where the thickness is less than 200 nm, and stress distribution due to the increase in thickness can be achieved. 1 The cohesive failure in the easy-adhesion layer 12 does not occur. Further, by setting the thickness to 500 nm or less, the deterioration of the planar shape can be suppressed as compared with the case where the thickness exceeds 200 nm.

[Second easy adhesion layer]
The 2nd easily bonding layer 13 is demonstrated. The second easy-adhesion layer 13 is a layer provided at a position farther from the support 11 than the first easy-adhesion layer 12, but is preferably the outermost layer of the laminated film 10. The second easy-adhesion layer 13 includes a second binder that is an acrylic resin or a urethane resin and a cross-linking agent. If necessary, the first easy-adhesion layer 12 is used to control the refractive index. Fine particles mainly containing any one of tin oxide, zirconium oxide, and titanium oxide described above, matting agents, slipping agents, surfactants, antistatic agents, and the like may be added.

  An acrylic resin or a urethane resin can be used as the second binder. Especially, when forming the 2nd easily bonding layer 13, it is especially preferable that it is a polymer which has a carboxyl group in a molecule | numerator. Moreover, the same thing as what was demonstrated by the 1st easily bonding layer 12 can be used for an acrylic resin and a urethane resin.

  As the second binder, the above polymer may be used by dissolving in an organic solvent, or an aqueous dispersion may be used. However, since the environmental load is small, it is preferable to perform aqueous coating using an aqueous dispersion. As the aqueous dispersion, the aforementioned commercially available polymer may be used.

  One type of polymer used as the second binder may be used alone, or two or more types may be mixed and used as necessary. Although there is no restriction | limiting in particular in the molecular weight of the polymer used as a 2nd binder, From a viewpoint of adhesive strength and a surface deterioration, the thing of about 3000-1 million in a weight average molecular weight is preferable.

  Although it does not restrict | limit especially as a crosslinking agent used with the 2nd easily bonding layer 13 of this invention, It is preferable that it is a carbodiimide type or an epoxy type crosslinking agent. The carbodiimide-based crosslinking agent used in the present invention (hereinafter sometimes referred to as a carbodiimide compound) is not particularly limited as long as it is a compound having a carbodiimide group in the molecule.

  The carbodiimide compound is usually synthesized by a condensation reaction of organic diisocyanate, but the organic group of the organic diisocyanate used for this synthesis is not particularly limited, either aromatic or aliphatic, or a mixture thereof. It can be used. However, aliphatic systems are particularly preferred from the viewpoint of reactivity. As the synthetic raw material, organic isocyanate, organic diisocyanate, organic triisocyanate and the like are used. Moreover, as a carbodiimide type crosslinking agent which can be used for this invention, it can also obtain as commercial items, such as carbodilite V-02-L2 (brand name: Nisshinbo Co., Ltd. product).

  Moreover, as an epoxy type crosslinking agent which can be used for this invention, if it is a compound which has two or more epoxy groups in a molecule | numerator, it will not restrict | limit in particular. Examples of the epoxy-based crosslinking agent include Dinacol (trade name: EX614B, EX521, EX512, EX301, EX313, EX314, EX810, EX811 manufactured by Nagase Kasei Co., Ltd.).

  The addition amount of the crosslinking agent contained in the second easy-adhesion layer 13 is preferably added in the range of 1 to 100% by mass, more preferably in the range of 5 to 50% by mass with respect to the binder. . By making the addition amount 1% by mass or more, the adhesion between the second easy-adhesion layer 13 and the upper layer is improved as compared with the case of less than 1% by mass. Moreover, when the addition amount is 100% by mass or less, the deterioration of the planar shape of the second easy-adhesion layer 13 is suppressed as compared with the case where the addition amount exceeds 100% by mass.

  Further, the second easy-adhesion layer 13 may contain a matting agent, a slip agent, a surfactant, an antistatic agent, etc. (hereinafter collectively referred to as an additive) as necessary. In this case, about the kind and quantity of various additives which can be used for the 2nd easily bonding layer 13, the thing similar to the above-mentioned 1st easily bonding layer can be used. In addition, since the detail of various additives is the same as that of the 1st easily bonding layer 12, description is abbreviate | omitted.

When a slipping agent is used as an additive for the second easy-adhesion layer 13, the type of the slipping agent is not particularly limited, but as a slipping agent that can be suitably used, for example, synthetic or natural wax, silicone Compound, R—O—SO ₃ M (where R represents a substituted or unsubstituted alkyl group (C _n H _{2n + 1} —; n is an integer of 3 to 20), and M represents a monovalent metal atom). And the like.

In addition, specific examples of the slipping agent include cellosol 524, 428, 428, 732-B, 920, B-495, hydrin P-7, D-757, Z-7-30, E-366, F- 115, D-336, D-337, Polylon A, 393, H-481, Hymicron G-110F, 930, G-270 (trade name: manufactured by Chukyo Yushi Co., Ltd.), Chemipearl W100, W200, W300, Wax type such as W400, W500, W950 (trade name: manufactured by Mitsui Chemicals), KF-412, 413, 414, 393, 859, 8002, 6001, 6002, 857, 410, 910, 851, X- 22-162A, X-22-161A, X-22-162C, X-22-160AS, X-22-164B, X-22-164C, X-22-170B X-22-800, X-22-819, X-22-820, X-22-821 ( trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) silicone and the _{like, C 16 H 33 -O-SO} 3 Examples thereof include compounds represented by general formulas such as Na and C ₁₈ H ₃₇ —O—SO ₃ Na. The addition amount of the lubricant is preferably set to 0.1 mg / m ² or more 50 mg / m ² or less. More preferably, the addition amount is 1 mg / m ² or more and 20 mg / m ² or less. By making the addition amount of the slip agent 0.1 mg / m ² or more, sufficient slipperiness can be exhibited. Moreover, the fall of the adhesive strength in an interface can be suppressed by making addition amount into 50 mg / m < ² > or less. The aliphatic wax that can be used in the present invention is described in detail in JP-A No. 2004-054161.

  The thickness of the 2nd easily bonding layer 13 shall be 50 nm or more and 200 nm or less from a viewpoint of adhesive strength and planar ensuring. Preferably they are 70 nm or more and 150 nm or less. By setting the thickness of the second easy-adhesion layer 13 to 50 nm or more, the adhesiveness with the upper layer is improved as compared with the case of less than 50 nm. Further, by setting the thickness to 200 nm or less, it is possible to suppress the deterioration of the planar shape as compared with the case where the thickness exceeds 200 nm.

  The formation method of the 1st easily bonding layer 12 and the 2nd easily bonding layer 13 will not be specifically limited if the layer of desired thickness can be formed. Therefore, the coating method is not limited, and a known method used when forming a thin film can be used. Examples of the method include a dipping method, a spinner method, a spray method, a roll coater method, a gravure method, a wire bar method, a slot extrusion coater method (single layer and multilayer), and a slide coater method. The first and second easy-adhesion layers 12 and 13 may be applied individually off-line in addition to on-line sequential application. Said method can be used as a formation method of the layer which concerns on this invention, ie, the 1st easily bonding layer 12, the 2nd easily bonding layer 13, and an upper layer.

  When applying both the first easy-adhesion layer 12 and the second easy-adhesion layer 13, a solvent (coating solvent) can be used. As the coating solvent, water, toluene, methyl alcohol, isopropyl alcohol, methyl ethyl ketone, and the like, and aqueous and organic solvent based coating solvents such as a mixed system thereof can be used. Among these, the method using water as a coating solvent is preferable in view of cost and ease of production. In addition, the coating solvent used for the 1st easily bonding layer 12 and the 2nd easily bonding layer 13 may be the same, and may differ.

  Moreover, the application | coating performed when forming the 1st easily bonding layer 12 and the 2nd easily bonding layer 13 may be performed after extending | stretching to a uniaxial direction, and may be performed after extending biaxially. However, in order to enable recovery and reuse of the base ear portion after lateral stretching, both the first easy-adhesion layer 12 and the second easy-adhesion layer 13 are preferably formed by application after biaxial stretching. Note that the easy-adhesion layers 12 and 13 may be formed not only on one surface but also on the other surface with respect to the support 11.

  The laminated film 10 of the present invention can be used as an optical film for use in liquid crystal displays, plasma displays, organic EL displays, and CRT displays. About these display devices, for example, “Display Advanced Technology” (published by Chizuka Tani, Kyoritsu Publishing Co., Ltd. 1998), “EL, PDP, LCD Display” (Toray Research Center Co., Ltd. issued in 2001), It is described in detail in “Color LCD” (Shunsuke Kobayashi, Sangyo Tosho Publishing Co., Ltd., published in 1990). In addition to the above-mentioned documents, the present invention can be applied to those described in page 74 of the August 2002 issue of Electric Journal.

  Hereinafter, the laminated film 10 and the manufacturing method thereof according to the present invention will be described with reference to examples. It should be noted that the types of materials, ratios of the materials, prescriptions, and the like shown in the following examples and the like may be changed as appropriate without departing from the spirit of the present invention. Accordingly, the scope of the present invention is not limited to the following examples. Moreover, in the following Examples etc., when the manufacturing method etc. of the laminated | multilayer film 10 are the same, it shall explain in detail in Example 1, and abbreviate | omits description in others.

[Example 1]
The support 11 of the laminated film 10 was formed by the following procedure. First, a polyethylene terephthalate (hereinafter referred to as PET) resin having an intrinsic viscosity of 0.66 polycondensed using Ge as a catalyst was dried to a moisture content of 50 ppm or less and melted in an extruder having a heater temperature of 280 to 300 ° C. . The melted PET resin was discharged from a die part onto a chill roll electrostatically applied to obtain an amorphous base. The obtained amorphous base was stretched 3.3 times in the base traveling direction, and then stretched 3.8 times in the width direction to obtain a support having a thickness of 100 μm.

After the both sides of the support having a thickness of 100 μm formed as described above are conveyed at a conveyance speed of 105 m / min and subjected to corona discharge treatment under the condition of 730 J / m ² , the coating amount is 7.1 cm ³ / As the m ² , the first easy-adhesion layer coating solution was applied by a bar coating method. After the coated substrate is dried at 180 ° C. for 1 minute to form the first easy-adhesion layer 12, the coating amount is set to 7.1 cm ³ / m ^{2 on} both surfaces of both first easy-adhesion layers 12 in succession. Two easy-adhesion layer coating solutions were applied by the bar coating method. By drying the support after coating at 170 ° C. for 1 minute, a laminated film 10 in which a coating layer 14 composed of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 was provided on both surfaces of the support 11 was produced. .

[First easy-adhesion layer coating solution]
As the first easy-adhesion layer coating solution, 154.6 parts by mass of a polyester resin binder (Z-687 solid content 25%, manufactured by Kyoyo Chemical Industry Co., Ltd.) and a carbodiimide compound (Nisshinbo Co., Ltd., Carbodilite) as a crosslinking agent V-02-L2, 75.9 parts by mass of solid content 10% (carbodiimide equivalent 385), and surfactant A (Nippon Yushi Co., Ltd., Rapisol B-90, solid content 1% aqueous solution, anionic) 12 .5 parts by mass and 15.5 parts by mass of the surfactant B (Sanyo Kasei Kogyo Co., Ltd., NAROACTY HN-100, solid content 5%, nonionic) are 1000 parts by mass as a whole. Thus, the one prepared by adding distilled water was used.

[Second easy adhesion layer coating solution A]
As the second easy-adhesion layer coating liquid A, 22.2 parts by mass of a polyurethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%) and a carbodiimide compound (manufactured by Nisshinbo Co., Ltd.) as a crosslinking agent , Carbodilite V-02-L2, 16.9 parts by weight of solid content (carbodiimide equivalent 385), Surfactant A (Nippon Yushi Co., Ltd., Rapisol B-90, 1% solid content aqueous solution, anionic) And 11.3 parts by mass of surfactant B (Sanyo Kasei Kogyo Co., Ltd., NAROACTY HN-100, solid content 5%, nonionic) 14.1 parts by mass of silica fine particle dispersion as matting agent A 1.4 parts by mass (manufactured by Nippon Aerosil Co., Ltd., aqueous dispersion of OX-50, solid content 10%) and colloidal silica dispersion liquid (Nissan Chemical Co., Ltd., Snowtex-X) as matting agent B L, solid content 10%) and 14.1 parts by weight of carnauba wax (Chukyo Oil Co., Ltd., Cellosol 524, solid content 3% aqueous solution) as a slipping agent. What prepared by adding distilled water so that it might become 1000 mass parts was used.

[Upper layer A]
As the upper layer A coating liquid, 225 parts by mass of Seika Beam EXF01 (B) (manufactured by Dainichi Seika Co., Ltd.), 75 parts by mass of methyl ethyl ketone, 2,4-bis (trichloromethyl) -6- [4- (N, N-diethoxycarbonylmethyl) -3-bromophenyl] -s-triazine was prepared by mixing 6.8 parts by mass. Next, after applying the coating liquid for the upper layer A to one surface (evaluation surface) of the produced laminated film 10 using a bar coater so that the film thickness after drying becomes 3 μm, 3 Dried for minutes. Next, it exposed with the exposure amount of 2000 mJ / cm < ² > using the ultra high pressure mercury lamp, and the upper layer A was formed by hardening the coating liquid mentioned above.

[Examples 2 to 9, Comparative Examples 1 to 6]
Examples 2 to 9 and Comparative Examples according to combinations of coating liquids and thicknesses with the first easy-adhesion layer, the second easy-adhesion layer A, the second easy-adhesion layer B, and the upper layer A and the upper layer B as shown in Table 1 1 to 6 were configured and the experiment was performed in the same manner as in Example 1. The coating solutions for the second easy-adhesion layer and the upper layer different from those in Example 1 are as follows. The thicknesses of the first easy-adhesion layer 12 and the second easy-adhesion layer 13 after drying were measured at a magnification of 200,000 times using a transmission electron microscope (JEM2010 (manufactured by Nippon Denka Co., Ltd.)). The film coated with each of the easy-adhesion layers 12 and 13 is embedded in an epoxy resin and dried, and then the cross section is cut with a microtome so as to have a thickness of 100 nm. The film thickness was measured at a magnification of 200,000, and 10 film thickness measurements were performed at 20 nm intervals on the captured image, and the average value excluding the maximum and minimum values was taken as the thickness. The interface between the layer and the second layer can be determined from an image taken with a transmission electron microscope.

[Second easy adhesion layer coating solution B]
As another coating liquid B for the second easy-adhesion layer, 34.1 parts by mass of an acrylic resin binder (manufactured by Daicel Chemical Industries, Ltd., AS-563A solid content 27.5%) and a carbodiimide compound ( Nisshinbo Co., Ltd., Carbodilite V-02-L2, solid content 10% (carbodiimide equivalent 385), 18.9 parts by mass, surfactant A (Nippon Yushi Co., Ltd., Rapizol B-90, solid content 1% 12.7 parts by weight of an aqueous solution, anionic), 15.5 parts by weight of a surfactant B (Sanyo Chemical Industries, Ltd., NAROACTY HN-100, solid content 1%, nonionic), and matting agent A 1.6 parts by mass of silica fine particle dispersion (manufactured by Nippon Aerosil Co., Ltd., aqueous dispersion of OX-50, solid content 10%), and colloidal silica dispersion (manufactured by Nissan Chemical Co., Ltd.) as matting agent B, Snow Su-XL, solid content 10%) and 2.5 parts by weight Carnauba wax (Chukyo Oil Co., Ltd., Cellosol 524, solid content 3% aqueous solution) as a slip agent, 15.5 parts by weight, What was prepared by adding distilled water so that the whole would be 1000 parts by mass was used, and the coating method was the same as the second easy-adhesive layer A.

[Upper layer B]
The coating liquid for forming the upper layer B comprises 19.2 parts by mass of acrylic polyol (manufactured by Dainippon Ink & Chemicals, Inc., Acrydic A807, solid content 50%) and polymethylmethacrylate resin particles (average particle size 22 μm). 26.1 parts by mass, 3.0 parts by mass of isocyanate (Takenate D110N manufactured by Takeda Pharmaceutical Co., Ltd., solid content 75%) and 25.9 parts by mass of butyl acetate were prepared. Next, after applying the upper layer B forming coating solution to one surface (evaluation surface) of the produced laminated film 10 using a bar coater so that the film thickness after drying becomes 20 μm, at 100 ° C. Dry for 3 minutes.

  Regarding the produced laminated film, the adhesiveness between the upper layer and the second easy-adhesion layer was evaluated by the following method under two conditions, before moisture absorption (Evaluation 1) and after moisture absorption (Evaluation 2). Moreover, evaluation of the coated surface state (evaluation 3) was performed. The evaluation shown below was carried out not only for Example 1 but also for other Examples and Comparative Examples.

[Evaluation 1. Adhesion between upper layer and second easy-adhesion layer (before moisture absorption)]
The sample was produced using the laminated | multilayer film which formed the 1st easily bonding layer, the 2nd easily bonding layer, and the upper layer with the said method. Using a single-blade razor on the surface of this sample, there were 6 scratches in the vertical and horizontal directions to form 25 squares. Next, a cellophane tape (No. 405, 24 mm width, manufactured by Nichiban Co., Ltd.) is attached on this, and after rubbing with poppy rubber from above, the coating layer formed earlier is peeled off in a 90-degree direction. The adhesiveness between the upper layer and the second easy-adhesion layer was evaluated by the following ranking by determining the number of peeled cells. The width of the scratch was 3 mm both vertically and horizontally.
Rank A: No peeling B rank: When the number of peeled squares is less than 1 Rank C: When the number of peeled squares is 1 or more and less than 3 D Rank: When the number of peeled squares is 3 or more and less than 20, Rank E : When the number of peeled cells is 20 or more

[Evaluation 2. Adhesion between upper layer and second easy-adhesion layer (after moisture absorption)]
First, a sample was prepared in the same manner as in Evaluation 1. Next, the sample is allowed to stand in an atmosphere of 80 ° C./90% RH and held for 16 hours, and then the sample is left to stand in an atmosphere of 23 ° C./60% RH to adjust the humidity for 3 hours. did. The adhesion between the upper layer of the sample after moisture absorption and the second easy-adhesion layer was evaluated by the same method as in Evaluation 1.

[Evaluation 3. (Applying surface of easy-adhesive film)
A sample was prepared by forming the first easy-adhesion layer 12 and the second easy-adhesion layer 13 on the surface of the support 11. Next, the sample was placed on a desk on which a black doskin cloth was bonded, and then the diffused light of a fluorescent lamp through a milky white acrylic plate was irradiated onto the coating layer. And the reflected light which generate | occur | produces here was observed visually and the coating nonuniformity was judged by the following reference | standard, and it evaluated in three steps as a coating surface shape. In the following evaluation, the rank B or higher is a level with no problem in terms of products.
Rank A: Coating unevenness is not visually confirmed in both the blackened sample and the untreated sample.
Rank B: Coating unevenness is visually confirmed in the sample after the blackening treatment, but is not confirmed in the untreated sample.
C rank: Coating unevenness is visually confirmed in both the sample after the blackening treatment and the untreated sample.

  In the above evaluation 3, in the visual judgment, blackening treatment was performed on a predetermined surface of the sample in order to prevent reflection from the back surface, and the transmittance of 550 nm light was adjusted to 1% or less. In the above blackening treatment, magic ink (artline oil-based marker supplement ink KR-20 black, manufactured by shachihata Co., Ltd.) was applied to the surface of the sample opposite to the surface to be observed, and then dried.

  As shown in Table 1, in Examples 1 to 9, there are slight differences in the evaluation results depending on the addition amount and type of the second binder and the crosslinking agent contained in the second easy-adhesion layer, but both are products. As a result, good evaluation results showing no problem in use are shown. On the other hand, in Comparative Examples 1 to 6, some of the evaluation results were excellent, but there were also items that were problematic when used as products.

  Next, on the laminated film produced in each of Examples 1 to 9, according to Example 1 described in JP-A-2001-324609, a light diffusion layer was formed to produce a light diffusion sheet. The adhesiveness between the laminated film and the light diffusion layer was practically acceptable, and a light diffusion sheet excellent in optical properties could be obtained.

After applying the photocurable resin composition having a thickness of 25 μm on the laminated film produced in each of Examples 1 to 9 by the bar coating method according to Example 1 described in JP-A No. 2001-14831. A prototype with a very small prismatic pattern (prism angle 90 degrees, prism pitch 50 μm, manufactured by Fuji Film Co., Ltd.) was placed and left in an oven at 80 ° C. for 3 minutes. Then, using a metal halide lamp as a light source from the coating layer side, the UV irradiation device with an irradiation intensity of 250 mW / cm ² was irradiated with ultraviolet rays of 1.0 J / cm ² , and the prototype with a very small prismatic pattern was separated, When a prism sheet was produced, the adhesive property between the laminated film and the prism layer was practically satisfactory, and a prism sheet excellent in optical characteristics could be obtained.

  On the laminated film produced in each of Examples 1 to 9, an active energy ray cured layer (hard coat layer) coating solution was dried by a bar coating method according to the examples described in JP-A-2001-323087. After coating to a thickness of 8 μm, this was cured by ultraviolet irradiation to form a hard coat layer to produce a hard coat sheet. The adhesion between the laminated film and the hard coat layer was good. In addition, a hard coat sheet excellent in optical properties could be obtained.

According to Example 1 described in Japanese Patent Laid-Open No. 2002-098803, a hard coat layer, a silver colloid layer, and an antireflection layer are laminated in this order on the laminated film produced in each of Examples 1 to 9 for reflection. When the prevention sheet was produced, the adhesion between the laminated film and the hard coat layer was good, and an antireflection sheet excellent in optical properties could be obtained. The coating thickness of the hard coat layer was 12 μm, the coating amount of the silver colloid layer was 70 mg / m ^2, and the coating thickness of the antireflection layer was 85 nm.

  When the diffusion film was removed from the backlight unit of a commercially available liquid crystal television and replaced with the diffusion film produced in Example 2, it was used under the environmental conditions of high temperature and high humidity of 60 ° C. and 90% RH. It was confirmed that there was no problem in practical use.

It is sectional drawing of the principal part which shows the laminated | multilayer film concerning this invention. It is sectional drawing of the principal part which shows the optical sheet which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laminated film 11 Support body 12 1st easily bonding layer 13 2nd easily bonding layer

Claims (5)

A support made of polyester;
A first easy-adhesion layer having a thickness of 200 nm to 500 nm, formed on at least one surface of the support;
An optical easy-adhesion film comprising: a second easy-adhesion layer formed on the surface of the first easy-adhesion layer and having a thickness of 50 nm to 200 nm. The first easy-adhesion layer has a binder containing a polyester resin,
The optically easily adhesive film according to claim 1, wherein the second easily adhesive layer has a binder containing an acrylic resin or a polyurethane resin.   The optically easily adhesive film according to claim 1, wherein the first easily adhesive layer and the second easily adhesive layer contain a carbodiimide-based crosslinking agent.   The optical easy-adhesion film according to any one of claims 1 to 3, and a prism layer formed on the second easy-adhesive layer of the optical easy-adhesion film, an antireflection layer, a light diffusion layer, an antiglare layer, An optical sheet comprising an upper layer composed of at least one of hard coat layers.   A display device comprising the optically easy-adhesive film according to claim 1 or the optical film according to claim 4.

Images