JP2007190817A - Laminated film and method for manufacturing the same, optical sheet using laminated film, and display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an easily adherent laminated film for use in a display unit such as a liquid crystal display. <P>SOLUTION: A support medium 11 composed of a polyester is biaxially drawn. A coated layer 14 having a multilayer structure is formed by forming a first layer 12 containing a first binder in the order adjacent to the support medium 11 at least on one side of the biaxially drawn support medium 11, and thereafter successively forming a second layer 13 containing a second binder composed of a resin selected from the group consisting of an acrylic resin, a polyurethane resin and a rubber-based resin. A compound having a plurality of carbodiimide structures in its molecule is contained in the first layer 12. A polyester resin is used as the first binder. The film thickness of the first layer 12 is not less than 10 nm and not greater than 500 nm. The laminated film 10 has a high adherent strength between the support medium 11 and the first layer 12; and when an upper layer is adhered onto the second layer 13, easy adherability is developed with respect to the upper layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laminated film having excellent adhesiveness and a method for producing the same. In addition, optical sheets such as prism sheets, antireflection sheets, light diffusion sheets, antiglare sheets, and hard coat sheets constituted using this laminated film, and liquid crystal displays, plasma displays, organic EL displays, CRT displays, etc. The present invention relates to a display device.

  A polyester film, particularly a biaxially oriented polyester film has a support made of polyester (hereinafter simply referred to as a polyester support) and exhibits excellent transparency, dimensional stability, chemical resistance, and low moisture absorption. It is widely used as various optical films. 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 It is used as a base film for sheets, hard coat sheets and the like.

  The base film used for such an optical film is required to have excellent transparency and is superior to a layer including a prism layer (hereinafter sometimes referred to as an upper layer) laminated thereon. Adhesion (easy adhesion) is required. However, it is difficult to directly bond the polyester support and the upper layer with sufficient strength. Therefore, generally, a method of providing a coating layer called an easy-adhesion layer on a polyester support is used. For example, a layer provided by a water-soluble coating solution containing a urethane resin on a polyester support. There has been proposed a base film having (see, for example, Patent Document 1).

However, since the chemical structure and physical properties of the support and the upper layer are often different, it is difficult to provide a layer that exhibits easy adhesion to both. Therefore, a base film having an easy-adhesion layer obtained by blending polyester and polyurethane on a polyester support and an acrylic coat layer on the easy-adhesion layer has been proposed (for example, see Patent Document 2).
JP-A-6-340049 JP 2000-229395 A

  In Patent Document 2, by forming an easy-adhesion layer in combination with polyester and polyurethane that exhibit easy-adhesiveness for each of the polyester support and the upper layer, the easy-adhesiveness is expressed for both. By providing an acrylic coating layer, it is possible to improve easy adhesion to the upper layer of a hard lens or the like. However, when the thickness of the upper layer is large, there is a problem that sufficient easy adhesion cannot be obtained.

  The present invention has been made to solve the above problems, and proposes a laminated film that becomes a base film having sufficient adhesion to both the support and the upper layer, and a method for producing the same. Is the first purpose. A second object of the present invention is to provide an optical sheet and a display device having excellent optical characteristics by using this laminated film.

  The laminated film of the present invention comprises an acrylic resin, a polyurethane resin, and a polyester resin rubber-based resin on at least one surface of a support made of polyester, followed by a first layer containing a first binder in the order close to the support. It has the application layer of the multilayer structure laminated | stacked with the 2nd layer containing the 2nd binder which consists of resin chosen from these.

  The first layer preferably contains a compound having a plurality of carbodiimide structures in the molecule. The first binder is preferably made of a polyester resin. Both the first layer and the second layer are preferably provided after biaxially stretching the support. In addition, it is preferable that the film thickness of a 1st layer is 10 nm or more and 500 nm or less.

  The optical sheet of the present invention has the laminated film described in any one of the above, and at least one of a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, and a hard coat layer, To do.

  Moreover, the display apparatus of this invention has the laminated | multilayer film described in any one of the above.

  The method for producing a laminated film of the present invention includes a step of biaxially stretching a support made of polyester, and subsequently, on at least one surface of the support, a first layer including a first binder from the order close to the support, And a coating layer forming step of forming a coating layer by forming a second layer containing a second binder made of a resin selected from an acrylic resin, a polyurethane resin, and a polyester resin rubber-based resin. To do.

  In the present invention, a resin selected from an acrylic resin, a polyurethane resin, and a rubber resin is formed on at least one surface of a support made of polyester, following a first layer containing a first binder from a moisture close to the support. Since a multilayer film is formed by providing a coating layer having a multilayer structure in which a second layer including a second binder made of is laminated, between the support and the first layer and between the second layer and the upper layer , Easy adhesion can be expressed. Moreover, since it has easy adhesiveness also between a 1st layer and a 2nd layer, even when an upper layer is thick, the laminated | multilayer film which shows easy adhesiveness with respect to both a support body and an upper layer can be provided. And the optical sheet obtained by combining this laminated | multilayer film with layers which have optical characteristics, such as a prism layer and an antireflection layer, and a display apparatus can be provided.

  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, a laminated film 10 of the present invention is formed by forming a first layer 12 and a second layer 13 on at least one surface of a support 11 made of polyester in order from the support 11. The coating layer 14 is provided. The first layer 12 and the second layer 13 are both layers made of resin and containing a binder. In the present invention, the binder included in the first layer 12 is referred to as a first binder, and the binder included in the second layer 13 is referred to as a second binder.

[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. Among these, 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.

  In order to improve mechanical strength, the polyester of the present invention is preferably stretched, 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. If the draw ratio is less than 1.5 times, sufficient mechanical strength cannot be obtained. Conversely, if it exceeds 7 times, it becomes difficult to obtain a uniform thickness.

  The thickness of the support 11 is 30 μm or more and 500 μm or less. More preferably, they are 100 micrometers or more and 300 micrometers or less. When the thickness is less than 30 μm, it is not preferable because the waist is lost and it becomes difficult to handle. On the other hand, when the thickness exceeds 500 μm, it is difficult to reduce the size and weight of the display device, and it is disadvantageous in terms of cost.

  The first layer 12 of the present invention is a layer that is directly laminated on the support 11. This layer must contain a binder, but preferably further contains a compound having a plurality of carbodiimide structures in the molecule. This layer may further contain fine particles, a surfactant, an antistatic agent and the like as required.

  The first binder of the present invention 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.

  Among the above, (b) polyurethane resin is a general term for polymers having a urethane bond in the main chain, and is usually obtained by 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 from the viewpoint of adhesion to the support 11 made of polyester. Moreover, as a polymer used as a 1st binder, what has a carboxyl group in a molecule | numerator among the above-mentioned polymers is especially preferable. Thereby, the 1st layer 12 which shows easy adhesiveness with respect to a support body can be obtained.

  Moreover, as said 1st binder, said polymer may be dissolved and used in 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. A commercially available polymer may be used as the aqueous dispersion. For example, Superflex 830, 460, 870, 420, 420NS (trade name: polyurethane manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Bondic 1370NS, 1320NS (trade name: Large) Polyurethane manufactured by Nippon Ink Chemical Co., Ltd.), Jurimer ET325, ET410, SEK301 (trade name: Nippon Pure Chemicals Co., Ltd. acrylic), Boncoat AN117, AN226 (trade name: Dainippon Ink Chemical Co., Ltd. acrylic) , Luck Star DS616, DS807 (trade name: Dainippon Ink and Chemicals Co., Ltd. styrene-butadiene rubber), Nippon LX110, LX206, LX426, LX433 (trade name: Nippon Zeon Co., Ltd. styrene-butadiene rubber), Nippon LX513, LX1551, L 550, LX1571 (trade name: Acrylonitrile-butadiene rubber manufactured by Nippon Zeon Co., Ltd.), Finetex Es650, Es2200 (trade name: polyester manufactured by Dainippon Ink & Chemicals, Inc.), Vironal MD1400, MD1480 (trade name: Toyobo ( Polyester)) and the like.

  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 usually preferable to use a polymer having a weight average molecular weight of about 3000 to 1000000. However, when the polymer having a weight average molecular weight of less than 3000 is used, the strength of the first layer 12 may be insufficient. On the other hand, when the polymer having a weight average molecular weight of more than 1000000 is used, the surface state of the first layer 12 is poor. There is.

  As the “compound having a plurality of carbodiimide structures in the molecule” (hereinafter referred to as a carbodiimide compound as appropriate) used in the present invention, any compound having a plurality of carbodiimide groups in the molecule can be used without particular limitation. be able to. Polycarbodiimide is usually synthesized by condensation reaction of organic diisocyanate, but the organic group of the organic diisocyanate used in 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.

  As examples of organic isocyanates, aromatic isocyanates, aliphatic isocyanates, and mixtures thereof can be used. Specifically, 4,4'-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane Diisocyanate, xylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,3-phenylene diisocyanate, etc. are used, and organic monoisocyanates include isophorone isocyanate, phenyl isocyanate. Cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like are used. Moreover, the carbodiimide type compound which can be used for this invention is also available as commercial items, such as carbodilite V-02-L2 (brand name: Nisshinbo Co., Ltd. product).

  It is preferable to add the carbodiimide type compound of this invention in the range of 1-200 mass% with respect to a binder, More preferably, it is adding in the range of 5-100 mass%. When the addition amount is less than 1% by mass, there is a possibility that prevention of fine particle peeling will be insufficient when the first layer 12 contains fine particles. On the other hand, when the addition amount exceeds 200% by mass, the surface shape of the first layer 12 may be deteriorated.

  Moreover, you may use various additives, such as microparticles | fine-particles and surfactant other than the above, for the 1st layer 12 according to a use. As the fine particles that can be used in the first 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 fine particles used in the present invention is preferably from 0.3 μm to 12 μm, more preferably from 0.5 μm to 9 μm. When the average particle size of the fine particles is less than 0.3 μm, the effect of improving the slip property is insufficient. On the other hand, when the average particle size exceeds 12 μm, the display quality of the display device may be deteriorated. The amount of the fine particles of the present invention varies depending on the average particle size, but is preferably 0.1 mg / m ² or more and 30 mg / m ² or less, more preferably 0.5 mg / m ² or more and 20 mg / m. ² or less. If the addition amount of the fine particles is less than 0.1 mg / m ² , the effect of improving the slip property may be insufficient. On the other hand, if the addition amount exceeds 30 mg / m ² , the transparency is lowered and the display of the display device is displayed. There is a risk of degrading quality. The average particle size of the fine particles referred to in the present invention is the particle size obtained for any 50 fine particles when the diameter of a circle having the same area as the fine particles when the fine particles were photographed with a scanning electron microscope was used as the particle size. Mean diameter.

Examples of the surfactant that can be used for the first 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). The addition amount of the surfactant 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. If the addition amount of the surfactant is less than 0.1 mg / m ² , repelling may occur. On the other hand, if it exceeds 30 mg / m ² , the surface state of the first layer 12 may be deteriorated.

An antistatic agent can also be used for the first layer 12. The type of the antistatic agent is not particularly limited. For example, an electron transmission polymer such as polyaniline or polypyrrole, an ion transmission 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 added so that the surface resistivity of the first 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. If the surface resistivity is less than 1 × 10 ⁵ Ω, the added amount of the antistatic agent increases, so that the transparency of the laminated film may be lowered. If the surface resistivity exceeds 1 × 10 ¹³ Ω, the antistatic effect is insufficient. On the other hand, there is a risk of inconvenience such as dust adhering.

  The thickness of the first layer 12 is set to be 10 nm or more and 500 nm or less in order to develop easy adhesion to the support 11. More preferably, the thickness of the first layer 12 is 30 nm or more and 150 nm or less. If the film thickness of the first layer 12 is less than 10 nm, the adhesion to the polyester support becomes insufficient, while if the film thickness exceeds 500 nm, the surface state may be deteriorated.

  The second layer 13 is a layer coated at a position farther from the support 11 than the first layer 12. The second layer 13 is preferably the outermost layer of the laminated film 10. The second layer 12 includes a predetermined second binder. In addition to the binder, the second layer 12 may contain additives such as a fine particle, a slip agent, a surfactant, and an antistatic agent as necessary. .

  In the present invention, a resin selected from an acrylic resin, a polyurethane resin, and a polyester resin rubber-based resin is used as the second binder. Note that the details of these resins are the same as those described in the description of the first binder, and a description thereof is omitted here. Among these, it is particularly preferable to use a polyurethane resin or an acrylic resin from the viewpoint of adhesiveness in addition to excellent transparency, and the polymer used as the second binder particularly has a carboxyl group in the molecule. preferable.

  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, The thing of about 3000-1 million is usually preferable in a weight average molecular weight. When the weight average molecular weight is less than 3,000, the strength of the coating layer may be insufficient, and when the weight average molecular weight exceeds 1,000,000, the coated surface may be poor.

  You may make the 2nd layer 13 contain an additive suitably according to a use. About the kind and quantity of microparticles | fine-particles, surfactant, and antistatic agent which can be used for the 2nd layer 13, the thing similar to the above-mentioned 1st layer can be used. The details of the various additives are the same as those of the first layer 12, and thus the description thereof is omitted.

When a slipping agent is used as an additive for the second layer 13, the type of the slipping agent is not particularly limited, but as a slipping agent that can be suitably used, for example, a synthetic or natural wax, a silicone compound, R—O—SO ₃ M (wherein R is a substituted or unsubstituted alkyl group (C _n H _{2n + 1} —; n is an integer of 3 to 20), 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 these slip agent is preferably to 0.1 mg / m ² or more 50 mg / m ² or less, more preferably 1 mg / m ² or more 20 mg / m ² or less. However, if the addition amount is less than 0.1 mg / m ² , the slipperiness of the second layer 13 may be insufficient. On the other hand, if it exceeds 50 mg / m ² , the planar shape of the second layer 13 may be obtained. May get worse.

  Although there is no restriction | limiting in particular in the thickness of the 2nd layer 13, In order to implement | achieve easy adhesiveness, ensuring excellent transparency, it is preferable that they are 10 nm or more and 5000 nm or less, More preferably, they are 20 nm or more and 1500 nm or less. . If the thickness of the second layer 13 is less than 10 nm, the adhesiveness with the upper layer may be insufficient. On the other hand, if the thickness exceeds 5000 nm, the surface state may be deteriorated.

  When forming the coating layer 14, it is preferable to provide the first layer 12 and the second layer 13 by coating. However, the method for forming the coating layer 14 is not particularly limited, and a known method such as bar coater coating or slide coater coating can be used. At this time, the first layer 12 and the second layer 13 may be formed by applying the same method or different methods. Moreover, when forming the 2nd layer 13, you may dry after apply | coating simultaneously with the 1st layer 12, and you may apply | coat after applying and drying the 1st layer 12.

  When applying both the first layer 12 and the second 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 layer 12 and the 2nd layer 13 may be the same, and may differ.

  Moreover, application | coating may be performed after extending | stretching to a uniaxial direction, and may be performed after extending biaxially. However, in order to enable recovery of the base ear after lateral stretching, it is preferable to apply after biaxial stretching. The coating layer 14 may be formed not only on one side but also on the other side of the support 11.

  The laminated film 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, an optical sheet having a laminated film obtained by the present invention and at least one of a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, and a hard coat layer exhibits excellent optical properties. Specific examples of these include prism sheets, antireflection sheets, light diffusion sheets, hard coat sheets, plasma display IR absorption sheets, electromagnetic wave shield sheets, toning sheets and the like used in liquid crystal displays. For example, In addition to the literature, it is described on page 74 of the August 2002 issue of Electric Journal.

  Hereinafter, the laminated film 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 of a laminated film, etc. are the same, it shall explain in detail in Example 1, and abbreviate | omits description in others.

A laminated film support 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 4.4 cm ³ / As m ² , the first layer coating solution was applied by a bar coating method. And after drying this at 180 degreeC for 1 minute and forming a 1st layer, the coating amount is 4.4 cm < ³ > / m < ² > on both surfaces of both the 1st layers, and the 2nd layer coating liquid is bar coat method Then, the film was dried at 170 ° C. for 1 minute to obtain a laminated film in which the first layer and the second layer were coated on both sides of the support. In addition, the film thickness of the 1st layer is observed by observing the laminated | multilayer film which apply | coated only 1st layer to the support body with the magnification 200,000 times using the transmission electron microscope (JEM2010 (made by JEOL Ltd.)). Was measured.

[First layer coating solution]
Said 1st layer coating liquid is 40.4 mass parts of polyester resin binders (Dai Nippon Ink Chemical Co., Ltd. make, Finetex ES650, solid content 29%), and surfactant A (Sanyo Chemical Industries Co., Ltd.). ), Sandet BL, solid content 10%, anionic) 9.3 parts by mass and surfactant B (Sanyo Chemical Industries, Naroacty HN-100, solid content 5%, nonionic) 21. Distilled water was added to prepare 8 parts by mass and 1000 parts by mass as a whole.

[Second layer coating solution]
The above-mentioned second layer coating solution is 35.9 parts by mass of a polyurethane resin binder (Daiichi Kogyo Seiyaku Co., Ltd., Superflex 460, solid content 38%) and a silica fine particle dispersion (Nippon Aerosil Co., Ltd.). OX-50 in water dispersion, solid content 10%) and colloidal silica dispersion (Nissan Chemical Co., Ltd., Snowtex-XL, solid content 10%) in 3.6 mass parts And 13.6 parts by mass of surfactant A, 31.8 parts by mass of surfactant B, and 7.6 slip agent (Chukyo Oil Co., Ltd., Carnauba wax dispersion Cellosol 524 solid content 3%). Distilled water was added and prepared so that the whole became 1000 parts by mass with respect to part by mass.

  Moreover, the following three evaluations were implemented regarding the laminated film in the middle of production, and the laminated film after production. In addition, evaluation shown below was implemented by not only Example 1 but the other Example and comparative example by the same method.

[1. Adhesion between support and first layer]
A laminated film in which only the first layer was applied to the support used in the examples was used as a sample, and this was immersed in distilled water at 60 ° C. for 16 hours, and water droplets adhering to the sample surface were then removed from paper (Kimwipe S-200 Immediately after lightly wiping with Crecia Co., Ltd., the surface of the sample is rubbed with a 0.1R diamond needle using a scratch strength tester (HEIDEN-18, Shinto Kagaku Co., Ltd.). Thus, the degree of peeling of the first layer when observed at a magnification of 100 was visually judged according to the following criteria, and evaluated as adhesion between the support and the first layer. The load applied to the diamond needle was 200 g.
Rank A: When there is no peeling Rank B: When the peeled area is less than 30% with respect to the area of the portion rubbed with the diamond needle Rank C: With respect to the area of the portion rubbed with the diamond needle 30% or more and less than 70% D rank: When the peeled area is 70% or more and 100% or less of the area rubbed with the diamond needle E rank: In addition to the portion rubbed with the diamond needle, its peripheral part When peeling occurs to the coating layer

[2. Adhesion between upper layer and second layer)
The prepared laminated film was conditioned for 24 hours in an atmosphere of 25 ° C. and 60% RH, and then the thickness of the obtained laminated film as a sample surface was 3 μm after drying using a bar coater. The following coating solution was applied to the sample and dried at 100 ° C. for 3 minutes. Then, after exposing and curing with an exposure amount of 2000 mJ / cm ² using an ultra-high pressure mercury lamp, the surface of this coating layer was scratched on the surface of the coating layer using a single-blade razor with 6 vertical and horizontal scratches, 25 squares. Formed. Next, a cellophane tape (No. 405, 24 mm width, manufactured by Nichiban Co., Ltd.) is attached on this, and then completely adhered by rubbing with poppy rubber from the top, and then peeled in the direction of 90 degrees, and the peeled squares are peeled off. By determining the number, the following ranking was performed to evaluate the adhesion between the upper layer and the second layer. 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

[Coating liquid formulation]
The above coating solution is 225 g of Seika Beam EXF01 (B) (manufactured by Dainichi Seika Co., Ltd.), 75 g of methyl ethyl ketone, 2,4-bis (trichloromethyl) -6- [4- (N, N-di Ethoxycarbonimethyl) -3-bromophenyl] -s-triazine was prepared by mixing with 6.8 g.

[3. (Applied surface)
The produced laminated film was irradiated on a coated layer with diffused light from a fluorescent lamp through a milky white acrylic plate from a desk on which a black doskin cloth was laminated, and the reflected light generated was visually observed. And the rainbow-shaped interference nonuniformity observed at this time was judged by the following reference | standard, and this was evaluated as a coating surface shape. Moreover, in visual judgment, the blackening process was performed with respect to the sample as forced condition evaluation, and it adjusted so that the transmittance | permeability of 500 nm light might be set to 1% or less. As 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. .
Rank A: Irregular interference unevenness is not visually confirmed in both the blackened sample and the untreated sample.
Rank B: Irregular interference unevenness is visually confirmed in the sample after the blackening treatment, but is not confirmed in the untreated sample.
Rank C: Rainbow-like interference unevenness is visually confirmed in both the blackened sample and the untreated sample.

  A laminated film was produced in the same manner as in Example 1 except that the first layer coating solution was changed. As the first layer coating liquid, 40.4 parts by mass of a polyester resin binder (Dainippon Ink & Chemicals, Finetex ES650, solid content 29%) and a carbodiimide compound (Nisshinbo Co., Ltd., Carbodilite V) -02-L2, solid content 10%, carbodiimide equivalent 385), 23.0 parts by weight of surfactant A, 9.3 parts by weight of surfactant A, and 21.8 parts by weight of surfactant B, What was prepared by adding distilled water so that the whole would be 1000 parts by mass was used.

  A laminated film was produced in the same manner as in Example 1 except that the binder used for the second layer coating solution was changed to an acrylic resin binder (Jurimer ET410 manufactured by Nippon Pure Chemical Co., Ltd.).

  A laminated film was produced in the same manner as in Example 1, except that the binder used for the second layer coating solution was changed to a rubber-based resin binder (Lacstar DS616, manufactured by Dainippon Ink and Chemicals, Inc.).

  The binder used for the first layer coating solution is a polyurethane resin binder (Superflex 870 SF870 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the binder used for the second layer coating solution is an acrylic resin binder (Dainippon Ink Chemical Co., Ltd.). A laminated film was produced in the same manner as in Example 1 except that it was changed to Boncoat AN117).

  A laminated film was produced in the same manner as in Example 1 except that the coating amount of the first layer was changed to 0.3 times.

  A laminated film was produced in the same manner as in Example 1 except that the coating amount of the first layer was changed to 3 times.

(Comparative Example 1)
In Comparative Example 1, only one coating layer was formed using the following coating solution. Other manufacturing conditions were the same as those in Example 1.

(Coating layer)
As a coating solution, 40.4 parts by mass of a polyester resin binder (Dainippon Ink & Chemicals, Finetex ES650, solid content 29%) and a silica fine particle dispersion (Nippon Aerosil Co., Ltd., OX- 50 parts of water dispersion, solid content 10%) and colloidal silica dispersion (Nissan Chemical Co., Ltd., Snowtex-XL, solid content 10%) 3.6 parts by weight 7.6 parts by mass of agent (manufactured by Chukyo Yushi Co., Ltd., Carnauba wax dispersion cellosol 524 3% solid content), 9.3 parts by mass of surfactant A, and 21.8 parts by mass of surfactant B And distilled water was added so that the whole would be 1000 parts by mass.

[Comparative Example 2]
A laminated film was produced in the same manner as in Comparative Example 1 except that the binder used in Comparative Example 1 was changed to a polyurethane resin binder (Superflex 460 SF460 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[Comparative Example 3]
Of the coating liquids used in Comparative Example 1, the binder is a polyester resin binder (Dainippon Ink Chemical Co., Ltd., Finetex ES650, solid content 29%) and a polyurethane resin binder (Daiichi Kogyo Seiyaku Co., Ltd.) A laminated film was produced in the same manner as in Comparative Example 1 except that a mixture of Flex 460 SF460) at a ratio of 1: 1 was used.

  Table 1 summarizes the evaluation results of the above examples and comparative examples. In each of Examples 1 to 7, although the adhesiveness between the support and the first layer or the upper layer and the second layer and the coated surface shape were slightly different depending on the binder to be used, all showed good evaluation results. On the other hand, in each of Comparative Examples 1 to 3, any of the above evaluation results was low. Table 1 shows the conditions outlined for each example and comparative example. In addition, although the film thickness of the 1st layer is also described, the value here is an approximate number which rounded up the first decimal place.

  Moreover, according to Example 1 described in Unexamined-Japanese-Patent No. 2001-324609 on the laminated film produced in each Example 1-7, when the light-diffusion layer was formed and the light-diffusion sheet was produced, lamination | stacking was carried out. Adhesiveness between the film and the light diffusion layer was practically satisfactory, and a light diffusion sheet having excellent optical characteristics could be obtained.

Moreover, according to Example 1 described in Unexamined-Japanese-Patent No. 2001-114831 on the laminated film produced in each Example 1-7, the 25-micrometer-thick photocurable resin composition was apply | coated by the bar-coat method. After that, a prototype with a very small prismatic pattern (prism angle 90 degrees, prism pitch 50 μm, manufactured by Fuji Photo 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.

  Moreover, according to the Example described in Unexamined-Japanese-Patent No. 2001-323087 on the laminated film produced in each Example 1-7, the active energy ray hardening layer (hard-coat layer) coating liquid was applied by the bar coat method. After coating so that the dry film thickness becomes 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 A hard coat sheet having good optical properties was obtained.

In addition, a hard coat layer, a silver colloid layer, and an antireflection layer were laminated in this order on the laminated film produced in each of Examples 1 to 7 according to Example 1 described in JP-A-2002-098803. When an antireflection 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.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laminated film 11 Support body 12 1st layer 13 2nd layer 14 Application layer

Claims (8)

  A second layer made of a resin selected from an acrylic resin, a polyurethane resin, and a rubber-based resin is formed on at least one surface of a support made of polyester, following the first layer including the first binder in the order close to the support. A laminated film comprising a coating layer having a multilayer structure in which a second layer containing a binder is laminated.   The laminated film according to claim 1, wherein the first layer contains a compound having a plurality of carbodiimide structures in the molecule.   The laminated film according to claim 1 or 2, wherein the first binder is made of a polyester resin.   The laminated film according to any one of claims 1 to 3, wherein each of the first layer and the second layer is provided after biaxially stretching the support.   5. The laminated film according to claim 1, wherein a thickness of the first layer is 10 nm or more and 500 nm or less.   An optical sheet comprising: the laminated film according to claim 1; and at least one of a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, and a hard coat layer. .   A display device comprising the laminated film according to claim 1. A step of biaxially stretching a support made of polyester;
Subsequently, a resin selected from an acrylic resin, a polyurethane resin, and a polyester resin rubber-based resin on at least one surface of the support body, the first layer including the first binder from the order close to the support body And a coating layer forming step of forming a coating layer by forming a second layer including a second binder comprising: a method for producing a laminated film.

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