JP2009241283A - Method for manufacturing laminated film and laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated film having excellent adhesiveness of a stretching film layer containing an alicyclic structure containing polymer and a urethane resin layer while maintaining characteristic as an optical material, and the laminated film. <P>SOLUTION: The method for manufacturing the laminated film having the stretching film layer containing the alicyclic structure containing polymer and the urethane resin layer includes a step for forming the stretching film layer where an average angle of contact with water with respect to the surface is 20-45° and a step for applying a water dispersing element of the water based urethane resin on the surface of the stretching film layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a laminated film and a laminated film produced by this method. More specifically, the present invention can be used for various image display devices such as a liquid crystal display device, an organic EL display device and a plasma display, and as an optical material. It is related with the manufacturing method of a laminated film with favorable adhesiveness of the stretched film layer and urethane resin layer containing an alicyclic structure containing polymer, and the laminated film manufactured by this method, maintaining the characteristic of this.

  In a liquid crystal display device, a retardation film for compensating a retardation due to birefringence of a liquid crystal cell is widely used. Until now, retardation films of various configurations have been proposed. Many of these retardation films are stretched films obtained by orienting a transparent resin by stretching. Examples of the stretched film include a film made of a polycarbonate resin and a film made of an alicyclic structure polymer, and in particular, from an alicyclic structure polymer in terms of excellent transparency, heat resistance, moisture resistance, and the like. The film that has become popular in recent years.

  However, a stretched film made of an alicyclic structure polymer has a problem that adhesion to other resin materials is low. Therefore, it has been difficult to produce an optical component formed by laminating a stretched film made of an alicyclic structure polymer and a film having another function.

  For such problems, Patent Documents 1 and 2 describe a film in which a polyurethane resin layer is formed on a norbornene-based resin film, which is one of films made of an alicyclic structure polymer. . However, the interface adhesive force between the norbornene resin film and the polyurethane resin layer is still insufficient.

Japanese Patent Laid-Open No. 2001-174637 JP 2006-201736 A

  An object of the present invention is to produce a laminated film having good adhesion between a stretched film layer containing an alicyclic structure-containing polymer and a urethane resin layer while maintaining the properties as an optical material, and the method. Furthermore, even if another resin material, particularly a polarizer, is laminated on the laminated film, the stretched film layer containing the alicyclic structure-containing polymer and the urethane resin layer are peeled off. It is providing the manufacturing method of a laminated film without this, and the laminated film manufactured by this method.

As means for solving the problems,
Claim 1
A method for producing a laminated film having a stretched film layer containing an alicyclic structure-containing polymer and a urethane resin layer,
Forming a stretched film layer having an average surface water contact angle of 20 to 45 degrees;
And a step of applying an aqueous dispersion of a water-based urethane resin to the surface of the stretched film layer.
Claim 2
The average water contact angle of the surface of the stretched film layer is set to 20 to 45 degrees by at least one treatment selected from the group consisting of corona treatment, plasma treatment, and ultraviolet irradiation treatment. It is a manufacturing method of description,
Claim 3
The water-based urethane resin is a self-emulsifying water-based urethane resin, the production method according to claim 1,
Claim 4
The aqueous dispersion of the water-based urethane resin contains a crosslinking agent, and is the production method according to any one of claims 1 to 3,
Claim 5
It is a laminated film manufactured by the manufacturing method as described in any one of Claims 1-4.

  According to the method for producing a laminated film of the present invention, it is possible to provide a laminated film having good adhesion between a stretched film layer containing an alicyclic structure-containing polymer and a urethane resin layer while maintaining the properties as an optical material. Furthermore, even when another resin material, particularly a polarizer, is laminated on this laminated film, a laminated film in which the stretched film layer containing the alicyclic structure-containing polymer and the urethane resin layer are not peeled is provided. be able to. Therefore, the laminated film manufactured by the manufacturing method of the present invention can be suitably used for an optical apparatus such as a liquid crystal display device.

  The method for producing a laminated film of the present invention is a method for producing a laminated film having a stretched film layer containing an alicyclic structure-containing polymer and a urethane resin layer, and has an average water contact angle of 20 to 45 degrees on the surface. The method includes a step of forming a stretched film layer and a step of applying an aqueous dispersion of an aqueous urethane resin to the surface of the stretched film layer.

  The stretched film layer used in the present invention contains an alicyclic structure-containing polymer. The alicyclic structure-containing polymer has an alicyclic structure in the repeating unit of the polymer, a polymer having an alicyclic structure in the main chain and a polymer having an alicyclic structure in the side chain. Any of these can be used. Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene) structure. From the viewpoint of mechanical strength, heat resistance, etc., the cycloalkane structure. Or a cycloalkene structure is preferable, and a cycloalkane structure is most preferable. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The heat resistance and the moldability of the film are highly balanced and suitable. The ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, preferably 55% by weight or more, Preferably it is 70 weight% or more, Most preferably, it is 90 weight% or more. It is preferable from the viewpoint of the transparency and heat resistance of the stretched film layer that the ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is in this range.

  Examples of the alicyclic structure-containing polymer include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. it can. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. An addition polymer of a monomer having a monomer, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Can be used.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca-3,7. -Diene (common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4. 0.1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene; Derivatives thereof; and the like.

  A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, And cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

  An addition polymer of a monomer having a norbornene structure and an addition copolymer of a monomer having a norbornene structure with another monomer copolymerizable with a monomer having a norbornene structure are prepared in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

Among norbornene-based resins, as repeating units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by weight or more based on the entire repeating units of the norbornene-based resin, and the content ratio of X and the content ratio of Y Is preferably 100: 0 to 40:60 by weight ratio of X: Y. By using such a resin, it is possible to obtain an optical film that has no dimensional change in the long term and is excellent in stability of optical characteristics.

  Examples of the monocyclic olefin resin include addition polymers of cyclic olefin monomers having a single ring such as cyclohexene, cycloheptene, and cyclooctene.

  As the cyclic conjugated diene polymer, a polymer obtained by cyclization reaction of an addition polymer of a conjugated diene monomer such as 1,3-butadiene, isoprene, chloroprene or chloroprene; cyclic conjugated such as cyclopentadiene or cyclohexadiene Mention may be made of 1,2- or 1,4-addition polymers of diene monomers; and their hydrides.

  Examples of vinyl alicyclic hydrocarbon polymers include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane and their hydrides; vinyl aromatic hydrocarbon monomers such as styrene and α-methylstyrene. Hydrogenated product obtained by hydrogenating the aromatic ring part contained in the polymer obtained by polymerization; copolymerization of vinyl alicyclic hydrocarbon monomers or vinyl aromatic hydrocarbon monomers with these vinyl aromatic hydrocarbon monomers Examples include a hydride of an aromatic ring of a copolymer such as a random copolymer with other possible monomers or a block copolymer. Examples of the block copolymer include diblock, triblock or higher multiblock, and gradient block copolymer.

  The hydrogenation method in the case of using a hydride as the alicyclic structure-containing polymer used in the present invention is not particularly limited and can be performed according to a known method. In order to obtain a hydride, a known hydrogenation catalyst containing a transition metal such as nickel or palladium is added to the polymer solution, and hydrogen is usually added to the reaction system at −10 to + 250 ° C., preferably 0 to 200 ° C. , 0.01 to 10 MPa, preferably 0.05 to 8 MPa, and allowed to react for 0.1 to 50 hours. The hydrogenation rate is usually 50% or more, preferably 70% or more, more preferably 90% or more. The higher the hydrogenation rate, the better the fluidity and heat resistance of the polymer.

  The molecular weight of the alicyclic structure-containing polymer used in the present invention is appropriately selected according to the purpose of use, but measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin does not dissolve) as a solvent. The weight average molecular weight (Mw) in terms of polyisoprene or polystyrene is usually 10,000 to 100,000, preferably 15,000 to 80,000, more preferably 20,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The glass transition temperature of the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, but is preferably in the range of 130 to 150 ° C, more preferably 135 to 145 ° C. When the glass transition temperature is lower than 130 ° C., the durability at high temperatures is deteriorated. When the glass transition temperature is higher than 150 ° C., the durability is improved, but normal stretching is difficult.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer is 1.2 to 3.5, preferably 1.5 to 3.0, more preferably 1.8. ~ 2.7. If this value exceeds 3.5, the low-molecular component increases, so the component with a short relaxation time increases, and even when the film has the same in-plane retardation Re at first glance, the relaxation during high-temperature exposure increases in a short time. The stability of the film may be reduced. On the other hand, those having a molecular weight distribution lower than 1.2 lead to a decrease in resin productivity and an increase in cost, which is not practical as a display member.

The alicyclic structure-containing polymer used in the present invention preferably has an absolute value of photoelastic coefficient of 10 × 10 ⁻¹² Pa ⁻¹ or less, more preferably 7 × 10 ⁻¹² Pa ⁻¹ or less. 4 × 10 ⁻¹² Pa ⁻¹ or less is particularly preferable. The photoelastic coefficient C is expressed as follows: birefringence is Δn and stress is σ.
C = Δn / σ
It is a value represented by If the photoelastic coefficient of the alicyclic structure-containing polymer exceeds 10 × 10 ⁻¹² Pa ⁻¹ , the in-plane retardation Re of the stretched film layer may vary widely.

  The alicyclic structure-containing polymer used in the present invention preferably contains substantially no particles. Here, “substantially free of particles” means that even if particles are added to a film containing an alicyclic structure-containing polymer, the increase in haze from the non-added state is 0.05% or less. It means that the amount is acceptable. In particular, since the alicyclic structure-containing polymer lacks affinity with many organic particles and inorganic particles, stretching the film containing the alicyclic structure-containing polymer to which particles exceeding the above range are added causes voids. As a result, the haze may be significantly reduced.

  The saturated water absorption of the alicyclic structure-containing polymer of the present invention is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, and particularly preferably 0.01% by weight or less. When the saturated water absorption is in the above range, the time-dependent change in the in-plane retardation Re and the thickness direction retardation Rth of the laminated film of the present invention can be reduced, and further, a polarizing plate comprising the laminated film of the present invention, Deterioration of the liquid crystal display device can be suppressed, and display on the display can be kept stable and good in the long term. The saturated water absorption is a value expressed as a percentage of the mass of the test piece before immersion after the test piece is immersed in water at a constant temperature for a fixed time. Usually, it is measured by immersing in 23 ° C. water for 24 hours. The saturated water absorption rate of the alicyclic structure-containing polymer in the present invention can be adjusted to the above value, for example, by reducing the amount of polar groups in the alicyclic structure-containing polymer. A resin having no group is desired.

  In the stretched film layer in the present invention, any resin can be contained as long as the required properties such as transparency and strength according to the use of the laminated film of the present invention can be maintained. For example, (meth) acrylic resin, polycarbonate resin, cellulosic resin, etc. can be mentioned. The resin other than the alicyclic structure-containing polymer contained in the stretched film layer in the present invention is preferably 10% by weight or less, more preferably 5% by weight or less.

  The alicyclic structure-containing polymer used in the present invention includes coloring agents such as pigments and dyes, fluorescent brighteners, dispersants, thermal stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antioxidants, You may add well-known additives, such as a lubricant, in the range which does not impair the effect of invention.

  The stretched film layer used in the present invention can be obtained by stretching a non-stretched film (hereinafter sometimes referred to as a raw film).

  The stretched film layer used in the present invention preferably has a total light transmittance of 80% or more in terms of 1 mm thickness. More preferably, the total light transmittance is 90% or more. In addition, the stretched film layer used in the present invention preferably has a haze at a thickness of 1 mm of 0.3% or less. More preferably, the haze is 0.2% or less. If the haze exceeds 0.3%, the transparency of the laminated film is lowered, and there is a possibility that it cannot be applied to the retardation film.

  In the stretched film layer used in the present invention, the values of in-plane retardation Re and thickness direction retardation Rth vary depending on the design of the display, but are appropriately selected from the range of about 10 to 500 nm for Re and −500 to 500 nm for Rth. The Note that Re in the present invention is the refractive index nx in the slow axis direction of the film, the refractive index ny in the direction perpendicular to the slow axis in the plane, the refractive index nz in the thickness direction, and the average thickness D of the film. Further, Rth in the present invention is a value defined by ((nx + ny) / 2−nz) × D.

  The stretched film layer used in the present invention has a Re variation within 10 nm, preferably within 5 nm, and more preferably within 2 nm. By setting the Re variation within the above range, it is possible to improve the display quality when used as a retardation film for a liquid crystal display device. Here, the variation in Re is the maximum value of Re when the Re is measured in the width direction of the film at a light incident angle of 0 ° (incident light beam and the surface of the stretched film layer in the present invention are orthogonal to each other). It is the difference between the value and the minimum value.

  The content of the residual volatile component in the stretched film layer used in the present invention is not particularly limited, but is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. is there. If the content of the residual volatile component exceeds 0.1% by weight, the optical characteristics of the laminated film of the present invention may change over time. By making the content of the volatile component in the above range, the dimensional stability can be improved, the change in Re and Rth of the laminated film over time can be reduced, and further, a polarizing plate or a liquid crystal provided with the laminated film of the present invention. Deterioration of the display device can be suppressed, and display on the display can be kept stable and good in the long term. The volatile component is a substance having a molecular weight of 200 or less contained in a trace amount in the laminated film of the present invention, and examples thereof include residual monomers and solvents. The content of volatile components can be quantified by analyzing the laminated film of the present invention by gas chromatography as the sum of substances having a molecular weight of 200 or less.

  The average thickness of the stretched film layer used in the present invention is usually 5 μm to 500 μm, preferably 20 to 300 μm, from the viewpoint of mechanical strength and the like. The thickness variation is preferably within ± 3% of the average thickness over the longitudinal direction and the width direction. By setting the thickness variation within the above range, variations in optical characteristics such as Re of the laminated film of the present invention can be reduced.

  The stretched film layer used in the present invention is preferably long. The long shape means one having a length of at least about 5 times the width direction of the film, preferably 10 times or more, and specifically wound in a roll shape. It has a length that can be stored or transported.

  The raw film is not particularly limited by the production method. The raw film is obtained by molding the above-described resin or the like by a known film forming method. Examples of the film forming method include a cast forming method, an extrusion forming method, and an inflation forming method. Among these, the melt extrusion method that does not use a solvent can reduce the amount of residual volatile components efficiently, and is preferable from the viewpoints of the global environment and work environment, and excellent manufacturing efficiency. Examples of the melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

  The stretching method of the raw film for obtaining the stretched film layer used in the present invention is not particularly limited, and may be stretched by either a uniaxial stretching method or a biaxial stretching method. The stretching method includes uniaxial stretching methods such as a method of uniaxial stretching in the longitudinal direction using the difference in peripheral speed on the roll side, a method of uniaxial stretching in the transverse direction using a tenter stretching machine, and the interval between fixed clips. At the same time as stretching in the longitudinal direction using the guide rail, the biaxial stretching method that stretches in the transverse direction depending on the spread angle of the guide rail, and the longitudinal direction using the difference in the peripheral speed between the rolls, and both ends thereof A biaxial stretching method such as a sequential biaxial stretching method in which a clip is gripped and stretched in the lateral direction using a tenter stretching machine, so that a feed force, a pulling force, or a pulling force at different speeds can be applied in the lateral or longitudinal direction. And a method of continuously and obliquely stretching in the direction of an arbitrary angle θ with respect to the width direction of the film using a tenter stretching machine.

  Examples of the apparatus used for stretching include a longitudinal uniaxial stretching machine, a tenter stretching machine, a bubble stretching machine, and a roller stretching machine.

  The temperature during stretching is preferably between (Tg-30 ° C) and (Tg + 60 ° C), more preferably (Tg-10 ° C), where Tg is the glass transition temperature of the material constituting the raw film. It is selected from temperatures between (Tg + 50 ° C.).

  What is necessary is just to select a draw ratio suitably according to the optical characteristic of the laminated | multilayer film to be used, and is 1.05-10.0, Preferably, it is 1.1-2.0.

The stretched film layer used in the present invention is subjected to a surface modification treatment before the water-based urethane resin layer is provided, so that the average water contact angle on the surface of the stretched film layer is in the range of 20 to 45 degrees. In addition, the water contact angle of this invention means the water contact angle just before forming a water-based urethane resin layer on the stretched film layer surface. The water contact angle is determined by the θ / 2 method using a contact angle meter. As the contact angle meter, for example, a contact angle meter (DM500) manufactured by Kyowa Interface Chemical Co., Ltd. can be used. The average water contact angle is calculated by measuring 20 water contact angles randomly selected within the range of 100 cm ² in the stretched film layer subjected to the surface modification treatment, and calculating the average of the measured values. By performing the surface modification treatment, functional groups such as a hydroxy group, a carboxyl group, a carbonyl group, an amino group, and a sulfone group can be introduced on the surface of the stretched film layer. Therefore, when the aqueous dispersion of the aqueous urethane resin is applied to the surface of the stretched film layer, the aqueous dispersion of the aqueous urethane resin is compatible with the surface of the stretched film layer and can be applied uniformly. A urethane resin layer having a thickness can be formed on the surface of the stretched film layer.

  Examples of the surface modification treatment include corona treatment, plasma treatment, and ultraviolet irradiation treatment. From the viewpoint of processing efficiency, corona treatment and plasma treatment are preferred, and corona treatment is particularly preferred. In addition, since the alicyclic structure-containing polymer used in the present invention has a small amount of polar groups in the polymer, the interaction between the molecular chains is small, and furthermore, since the stretching treatment is performed, the stretched film layer has molecules. The effect of reducing the chain entanglement is also added, and the material is easily broken in the thickness direction of the stretched film layer. Therefore, the surface modification treatment conditions in the stretched film layer are extremely important, and it is preferable to treat the stretched film layer surface under the mildest conditions possible.

  The corona treatment used in the present invention is preferably a wire electrode, a planar electrode, or a roll electrode as the electrode structure, but in order to reduce damage to the stretched film layer as much as possible, it is between the stretched film layer and the electrode. It is preferable to perform treatment with a dielectric interposed between them, and it is preferable to use a roll electrode as the electrode.

  As the material of the electrode, metals such as iron, copper, aluminum, and stainless steel can be used. As the electrode shape, electrodes such as a thin plate shape, a knife edge shape, and a brush shape can be used.

  The dielectric preferably has a relative dielectric constant of 10 or more, and has a structure in which a dielectric is sandwiched between upper and lower electrodes. Dielectric materials include ceramics, silicone rubber, polytetrafluoroethylene, polyethylene terephthalate and other plastics, glass, quartz, silicon dioxide, aluminum oxide, zirconium dioxide, titanium dioxide and other metal oxides, and compounds such as barium titanate. Is mentioned. In particular, interposing a solid dielectric having a relative dielectric constant of 10 or more (in an environment of 25 ° C.) is advantageous in that corona treatment can be performed at a high speed with a low voltage. Examples of the solid dielectric having a relative dielectric constant of 10 or more include metal oxides such as zirconium dioxide and titanium dioxide, oxides such as barium titanate, and silicon rubber. The dielectric thickness is preferably in the range of 0.3 to 1.5 mm. If the thickness of the dielectric is too thin, dielectric breakdown is likely to occur, and if it is too thick, the applied voltage needs to be increased, resulting in poor efficiency.

  The distance between the stretched film layer and the electrode is preferably 0.5 to 10 mm. If the thickness is less than 0.5 mm, only the thin stretched film layer can pass, and if there is a seam, the stretched film layer may hit the electrode when passing, and the stretched film layer may be damaged. On the other hand, if it exceeds 10 mm, the applied voltage becomes high, so that the power source becomes large and the plasma becomes a streamer shape.

  The output of the corona treatment used in the present invention is preferably a condition for treating as little damage as possible on the stretched film layer surface, specifically 0.02 to 5 kW, preferably 0.04 to 2 kW. More preferred. Also, the best corona treatment method is to perform the corona treatment several times within the above range at the lowest possible output.

The density of the corona treatment used in the present invention should be such that the average water contact angle of the stretched film layer can be in the range of 20 to 45 degrees. Specifically, it is preferably a 1~200W · min / ^{m 2,} more preferably 5~150W · min / ^{m 2,} further preferably 10~100W · min / ^{m 2.} When the treatment density is low, the applicability of the aqueous dispersion of the water-based urethane resin is lowered. Moreover, when high, the stretched film layer surface will be destroyed and the adhesiveness of a urethane resin layer will fall.

  The frequency of the corona treatment used in the present invention is preferably 5 to 100 kHz, and more preferably 10 to 50 kHz. When the frequency is lowered, the uniformity of the corona discharge treatment is deteriorated, and unevenness of the corona discharge treatment occurs. In addition, when the frequency is increased, there is no particular problem when performing a high-output corona discharge treatment, but when performing a low-output corona discharge treatment, it becomes difficult to perform a stable treatment. Unevenness occurs.

  When corona discharge is performed, it is preferable to surround the electrode with a casing, to put an inert gas inside the casing, and to apply gas to the electrode portion because plasma can be generated in a finer state. As the inert gas, helium, argon, or nitrogen can be used.

  Examples of the plasma treatment used in the present invention include glow discharge treatment and flame plasma treatment. As the glow discharge, either a vacuum glow discharge process performed under vacuum or an atmospheric pressure glow discharge process performed under atmospheric pressure can be used, but an atmospheric pressure glow discharge process performed under atmospheric pressure is preferable from the viewpoint of productivity. . In addition, the atmospheric pressure in this invention is the range of 700-780 Torr. In the glow discharge treatment, a stretched film layer is placed between opposing electrodes, a plasma-exciting gas is introduced into the apparatus, and a high-frequency voltage is applied between the electrodes, thereby plasma-exciting the gas and causing a glow between the electrodes. It is what discharges. Thereby, the stretched film layer surface is processed and the hydrophilicity of the stretched film layer surface is enhanced.

  The plasma-excitable gas refers to a gas that is plasma-excited under the above conditions. Plasma-excitable gases include chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane and mixtures thereof, and inert gases such as argon and neon, carboxyl groups and hydroxyl groups. And a reactive gas capable of imparting a polar functional group such as a carbonyl group.

  The frequency of the high-frequency voltage is preferably in the range of 1 kHz to 100 kHz, and the magnitude of the voltage is preferably in a range in which the electric field strength when applied to the electrode is 1 to 100 kV / cm.

  Examples of the ultraviolet irradiation treatment used in the present invention include treatments using lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low pressure mercury lamps, high pressure mercury lamps, and excimer lamps. For example, a commercially available product such as an H lamp, a D lamp, or a V lamp manufactured by Fusion System can be used. Irradiation conditions vary depending on each lamp. For example, the wavelength is mainly reduced by using a low-pressure mercury lamp and irradiating mainly 185 nm and 254 nm ultraviolet rays with a light amount of 1 to 3,000 mJ / cm 2 or using an excimer lamp. A method of irradiating 172 nm ultraviolet rays with a light amount of 1 to 3,000 mJ / cm @ 2 can be mentioned. Such ultraviolet rays generate active oxygen and ozone, act on the surface of the stretched film layer, and can modify the surface characteristics of the stretched film layer.

  The urethane resin layer used in the present invention is obtained by coating an aqueous dispersion of an aqueous urethane resin directly on the surface of the stretched film layer that has been surface-modified. The aqueous dispersion of an aqueous urethane resin is formed by dispersing an aqueous urethane resin in water, and can take the form of an emulsion, a colloidal dispersion, an aqueous solution, or the like.

  The aqueous urethane resin is not particularly limited. For example, (i) an aqueous system obtained by reacting a component containing an average of two or more active hydrogens in one molecule and (ii) a polyvalent isocyanate component. The urethane resin, or the above component (i) and component (ii) is urethanated in an organic solvent that is inert to the reaction and has a high affinity for water under the condition of excess isocyanate group to obtain an isocyanate group-containing prepolymer. Then, there is an aqueous urethane resin produced by neutralizing the prepolymer, extending the chain with a chain extender, and adding water to form a dispersion. These water-based urethane resins may contain an acid component (acid residue).

  The chain extension method of the isocyanate group-containing prepolymer may be a known method. For example, water, a water-soluble polyamine, glycols or the like is used as the chain extender, and the isocyanate group-containing prepolymer and the chain extender component are used. May be reacted in the presence of a catalyst as necessary.

  The component containing two or more active hydrogens in average in one molecule of the component (i) is not particularly limited, but one having a hydroxyl active hydrogen is preferable. Specific examples of such compounds include the following.

(1) Diol compound:
Ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclodecane dimethanol, 1,4-cyclohexane dimethanol and the like.

(2) Polyether diol:
Alkylene oxide adducts of the above diol compounds, ring-opening (co) polymers of alkylene oxides and cyclic ethers (such as tetrahydrofuran), such as polyethylene glycol, polypropylene glycol, ethylene glycol-propylene glycol (block or random) copolymers, Glycol, polytetramethylene glycol, polyhexamethylene glycol, polyoctamethylene glycol and the like.

(3) Polyester diol:
Dicarboxylic acids (anhydrides) such as adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid and phthalic acid, and ethylene glycol, propylene glycol and 1,4-butane as mentioned in (1) above Those obtained by polycondensation with a diol compound such as diol, 1,6-hexanediol, 1,8-octamethylenediol, neopentylglycol and the like under conditions of excess hydroxyl group. Specifically, ethylene glycol-adipic acid condensate, butanediol-adipine condensate, hexamethylene glycol-adipic acid condensate, ethylene glycol-propylene glycol-adipic acid condensate, or lactone ring opening using glycol as an initiator. Polymerized polylactone diol and the like.

(4) Polyether ester diol:
An ether group-containing diol (polyether diol or diethylene glycol of (2) above) or a mixture of this and another glycol is added to (anhydrous) dicarboxylic acid as exemplified in (3) above to react with an alkylene oxide. For example, polytetramethylene glycol-adipic acid condensate.

(5) Polycarbonate diol:
General formula HO-R- (OC (O) -O-R) x-OH (wherein R is a saturated fatty acid diol residue having 1 to 12 carbon atoms, x is the number of repeating units of the molecule) , Usually an integer of 5 to 50). These include a transesterification method in which a saturated aliphatic diol and a substituted carbonate (diethyl carbonate, diphenyl carbonate, etc.) are reacted under the condition that the hydroxyl group is excessive, the saturated aliphatic diol and phosgene are reacted, or as necessary. Then, it can be obtained by a method of further reacting with a saturated aliphatic diol.

  The compounds as exemplified in the above (1) to (5) can be used alone or in combination of two or more.

  As the polyisocyanate component (ii) to be reacted with the component (i), an aliphatic, alicyclic or aromatic compound containing an average of two or more isocyanate groups in one molecule can be used.

  As the aliphatic diisocyanate compound, an aliphatic diisocyanate having 1 to 12 carbon atoms is preferable, and examples thereof include hexamethylene diisocyanate and 2,2,4-trimethylhexane diisocyanate. The alicyclic diisocyanate compound is preferably an alicyclic diisocyanate having 4 to 18 carbon atoms, and examples thereof include 1,4-cyclohexane diisocyanate and methylcyclohexylene diisocyanate. Examples of the aromatic isocyanate include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate.

  In addition, those containing an acid residue in the water-based urethane resin can be dispersed in water without using a surfactant (hereinafter also referred to as an emulsifier) or in a small amount. Therefore, it is expected that the water resistance of the coating film is improved. This is called a self-emulsifying type, and means a state in which the polyurethane resin is dispersed and stabilized in water only by molecular ionicity without using a surfactant. Since a surfactant is unnecessary, it is preferable because it has excellent adhesiveness with an alicyclic structure-containing polymer and can maintain high transparency. The content of the acid residue is preferably in the range of 25 to 150 mgKOH / g, preferably 30 to 100 mgKOH / g, as the acid value of the water-based urethane resin. If the acid value is less than 25 mgKOH / g, water dispersibility tends to be insufficient, and a surfactant is often required in combination. On the other hand, if the acid value is greater than 150 mgKOH / g, the water resistance of the coating tends to be poor. .

  As a method for introducing an acid group into a water-based urethane resin, a conventionally used method can be used without any particular limitation. For example, dimethylolalkanoic acid is a part of the glycol component described in (2) to (4) above. Or the method of introduce | transducing an acid group by introduce | transducing a carboxyl group to polyether diol, polyester diol, polyether ester diol, etc. previously by replacing with all is preferable. Examples of the dimethylolalkanoic acid used here include dimethylolacetic acid, dimethylolpropionic acid, and dimethylolbutyric acid.

  Moreover, since the water dispersibility of water based urethane resin can be improved by neutralizing the acid component which remains in water based urethane resin, it is preferable to neutralize. Examples of the neutralizing agent that neutralizes the acid component include organic amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine, and triethanolamine, and inorganic such as sodium hydroxide, potassium hydroxide, and ammonia. A base etc. can be mentioned.

  The water-based urethane resin used in the present invention preferably has a number average molecular weight of 1,000 or more, more preferably 20,000 or more. However, it is preferably 1,000,000 or less, more preferably 200,000 or less.

  As the water-based urethane resin, commercially available water-based urethane resins can be used as they are. For example, “Adekabon titer” series manufactured by Asahi Denka Kogyo Co., Ltd., “Made by Mitsui Toatsu Chemical Co., Ltd.” "Olestar" series, "Bondic" series by Dainippon Ink & Chemicals, Ltd., "Hydran" series, "Imperil" series by Bayer, "Sofranate" series by Sofran Japan, Kao Corporation ) "Poise" series, Sanyo Chemical Industries "Samprene" series, Hodogaya Chemical Co., Ltd. "IZerax" series, Daiichi Kogyo Seiyaku "Superflex" series The “Neolets” series manufactured by Zeneca Corporation can be used.

  In addition, heat-resistant stabilizers, weather-resistant stabilizers, leveling agents, antistatic agents, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, pigments, natural oils, synthetic oils can be added to the above water-based urethane resins. An appropriate amount of other compounding agents such as oil, wax, and crosslinking agent may be added.

  When the thickness of the urethane resin layer formed on the stretched film layer is 1 μm or less, it is preferable to further add a crosslinking agent for the purpose of improving the mechanical strength of the urethane resin layer. As a crosslinking agent that can be used in the present invention, any compound having a functional group that reacts with a reactive group of an aqueous urethane resin can be used without particular limitation, but an aqueous epoxy compound, an aqueous amino compound, an aqueous isocyanate, and the like. It is preferable to use a compound or an aqueous carbodiimide compound from the viewpoint of versatility of the material, and particularly preferable to use an aqueous epoxy compound or an aqueous amino compound from the viewpoint of adhesiveness.

  The water-based epoxy compound may be any compound that is soluble in water or has two or more epoxy groups emulsified. For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol; 1 mol of glycol such as 1,4-butanediol, 1,6-hexane glycol, neopentyl glycol and 2 mol of epichlorohydrin Diepoxy compounds obtained by etherification, polyepoxy compounds obtained by etherification of 1 mol of polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbitol and 2 mol or more of epichlorohydrin, phthalic acid, terephthalic acid Epoxy compounds such as diepoxy compounds obtained by esterification of 1 mol of dicarboxylic acid such as oxalic acid and adipic acid and 2 mol of epichlorohydrin. It is.

  The aqueous amino compound may be any compound that is soluble in water or has two or more amino groups emulsified. For example, carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, acrylic acid dihydrazide, etc. A compound, a melamine resin, a urea resin, a guanamine resin, etc. are mentioned.

  The water-based isocyanate compound may be a compound that has solubility in water or has two or more non-blocked isocyanate groups and block-type isocyanate groups emulsified. Examples of the non-blocking isocyanate compound include compounds obtained by reacting a polyfunctional isocyanate compound with a monovalent or polyvalent nonionic polyalkylene ether alcohol. As the block type isocyanate compound, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′-diphenylmethane diisocyanate (MDI), xylylene diene Isocyanate (XDI), isophorone diisocyanate (IPDI), methylcyclohexyl diisocyanate (H6TDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,3-bis (isocyanatomethyl) cyclohexane (H6XDI), tetramethylxylylene diisocyanate (TMXDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), hexamethylene diisocyanate (HDI), norbornene diisocyanate (NBDI), 2, 4,6-triisopropylphenyl diisocyanate (TIDI), 1,12-diisocyanatododecane (DDI), 2,4, -bis- (8-isocyanatooctyl) -1,3-dioctylcyclobutane (OCDI), n-pentane- 1,4-diisocyanates and their isocyanurate-modified products, adduct-modified products, burette-modified products, allophanate-modified products, and polymers having one or more isocyanate groups are modified with polyoxyalkylene groups, carboxyl groups, etc. And a compound obtained by making it water-soluble and / or water-dispersible and masking an isocyanate group with a blocking agent (phenol, ε-caprolactam, etc.).

  The water-based carbodiimide compound may be a compound compound that is soluble in water or has two or more carbodiimide bonds (—N═C═N—) emulsified. A compound having two or more carbodiimide bonds is obtained by a method in which two isocyanate groups are decarboxylated to form -N = C = N- using two or more molecules of polyisocyanate and a carbodiimidization catalyst. be able to. The polyisocyanate and the carbodiimidization catalyst used when producing a compound having two or more carbodiimide bonds are not particularly limited, and conventionally known ones can be used.

  The ratio of the water-based urethane resin and the crosslinking agent may be 1 to 30 parts by weight, preferably 5 to 15 parts by weight (solid content) of the cross-linking agent with respect to 100 parts by weight (solid content) of the water-based urethane resin. preferable. By blending, the strength of the coating film and the stability of the coating solution can be achieved.

  From the viewpoint of film optical properties, the particle size of the aqueous urethane resin particles in the aqueous dispersion of the aqueous urethane resin in the present invention is preferably 0.01 μm to 0.4 μm. The particle size of the water-based urethane resin particles can be measured by a dynamic light scattering method, and for example, can be measured by a light scattering photometer DLS-8000 series manufactured by Otsuka Electronics Co., Ltd. The aqueous dispersion of the water-based urethane resin in the present invention may contain a water-soluble solvent. Examples of the water-soluble solvent include methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and the like.

  The urethane resin layer in the present invention preferably has a pencil hardness of H or more at a thickness of 20 μm. By setting it in the above range, scratch resistance can be imparted to the film.

  The urethane resin layer can be formed by coating an aqueous dispersion of an aqueous urethane resin on one or both sides of the stretched film layer that has undergone surface modification treatment.

  The method for coating the aqueous dispersion of the water-based urethane resin on the stretched film layer is not particularly limited, and a known coating method can be employed. Specific coating methods include wire bar coating, dipping, spraying, spin coating, roll coating, gravure coating, air knife coating, curtain coating, slide coating, and extrusion coating. Can be mentioned. The coating amount of the aqueous dispersion of the water-based urethane resin is not particularly limited, but the thickness after curing is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm, and particularly preferably 0.1 to 1 μm. Within the above range, sufficient adhesive strength between the stretched film layer and the urethane resin layer can be obtained, and a laminated film free from defects such as warping of the film can be provided.

  The urethane resin layer and the stretched film layer preferably have an interface refractive index difference of 0.05 or less. When the interface refractive index difference is within the above range, it is possible to suppress light loss when light is transmitted through the laminated film of the present invention.

  The urethane resin layer can be provided not only on one side of the stretched film layer but also on both sides. By providing it on both sides of the stretched film layer, web handling can be improved in the case of a long film.

  The laminated film according to the present invention is produced into a polarizing plate by further laminating a polarizer on the surface of the urethane resin layer in the laminated film, and the present invention is provided via an adhesive on at least one surface of the polarizer. It can manufacture by laminating | stacking this laminated film. When the laminated film of the present invention is laminated only on one side of the polarizer, a highly transparent film may be laminated on the other side of the polarizer. The polarizing plate is also referred to as a polarizing film or a polarizing sheet.

  The polarizer can be obtained by adsorbing iodine or dichroic dye on a polyvinyl alcohol film and then uniaxially stretching in a boric acid bath, and adsorbing iodine or dichroic dye on a polyvinyl alcohol film. And stretching, and a part of the polyvinyl alcohol unit in the molecular chain can be modified to a polyvinylene unit. A polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer, a multilayer polarizer, and a cholesteric liquid crystal polarizer, can also be used as the polarizer. Among these, a polarizer comprising polyvinyl alcohol is preferable. The polarization degree of the polarizer is preferably 98% or more, more preferably 99% or more. The thickness (average thickness) of the polarizer is preferably 5 μm to 80 μm.

  The adhesive for adhering the polarizer and the laminated film of the present invention is not particularly limited as long as it is optically transparent, and is an aqueous adhesive, a solvent-type adhesive, a two-component curable adhesive, an ultraviolet curable type. Examples thereof include an adhesive and a pressure-sensitive adhesive. Among these, a water-based adhesive is preferable, and a polyvinyl alcohol-based water-based adhesive is particularly preferable.

  The average thickness of the adhesive layer is preferably 0.05 to 5 μm, and more preferably 0.1 to 1 μm.

  As a method of laminating the polarizer and the laminated film of the present invention, an ordinary method can be used. For example, after applying an adhesive on one surface of the polarizer, a roll laminator is used to The method of bonding and drying the surface provided with the urethane resin layer in the laminated film of the present invention is preferred. The drying time and the drying temperature are appropriately selected according to the type of adhesive.

  The laminated film of the present invention has good adhesion to a film, sheet or substrate formed of another resin and has excellent optical properties. Besides a plate, it can be formed on a film with an antireflection film, a protective film, a retardation film, a viewing angle widening film, a brightness enhancement film, and the like.

  The laminated film of the present invention is suitably used for various image display devices such as organic EL display devices and plasma displays.

Next, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to the following Example.
The test and evaluation in an Example and a comparative example were performed with the following method.

(Evaluation methods)
<Measurement of water contact angle>
The water contact angle was measured using a contact angle meter DM500 manufactured by Kyowa Interface Science Co., Ltd. In the measurement, 3 μl of pure water was dropped on the surface to be measured, and the water contact angle was measured by the θ / 2 method. The average water contact angle (Da) was determined by measuring 20 water contact angles at random within the range of 100 cm ² of the stretched film layer subjected to the surface modification treatment, and calculating the average of the measured values.
<Pencil hardness of urethane resin layer>
Based on JIS K5600-5-4, measurement was performed with a load of 500 g at a thickness of 10 μm.
<Refractive index of urethane resin layer>
A urethane resin layer having a thickness of 200 nm is formed on a glass substrate, and using a high-speed spectroscopic ellipsometer (manufactured by JA Woollam, M-2000U), a measurement wavelength of 245 to 1000 nm, an incident angle of 55 °, 60 °, and The measurement was made at 65 °, and the value calculated based on the measured value was taken as the refractive index.
<Surface observation of the coated surface after coating the coating solution on the stretched film layer after the surface treatment>
The coated surface after applying the coating solution onto the stretched film layer after the surface treatment was randomly sampled at 10 points with a size of 5 × 5 mm, and a field emission scanning electron microscope (S-4700, Hitachi, Ltd.). (Manufactured by Seisakusho) was observed for the presence or absence of coating repelling.
<Abrasion resistance test>
The entire surface of the laminated film was subjected to a load of 0.02 MPa on # 0000 steel wool, and the surface after 5 reciprocations at a stroke width of 25 mm and a speed of 30 mm / sec was visually observed and evaluated according to the following criteria. .
(Double-circle): A crack is not recognized at all.
○: Slightly weak scratches are observed when carefully observed.
X: Scratches are observed.
<Optical characteristics>
Based on JIS K7361-1997, the produced laminated film was measured for total light transmittance and haze of the laminated film by using “turbidimeter NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. Moreover, the presence or absence of interference fringes on the surface of the laminated film was visually evaluated.
<Measurement of peel strength of polarizing plate>
The produced polarizing plate was cut into a width of 15 mm, the polarizer and the laminated film were pulled in the 180 ° direction, and the strength was measured (measurement of 180 ° peel strength). In addition, the test was implemented at the tensile speed of 50 mm / sec using the universal tension compression tester (TCM-500CR: Shinsei Tsushin Kogyo Co., Ltd. product) as a measuring machine.

(Production Example 1)
<Production of stretched film layer (A)>
A pellet of an alicyclic structure-containing polymer resin (ZEONOR 1430, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature 135 ° C.) was dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated. Using a T-die film melt extrusion molding machine with a resin melt kneader equipped with a screw, a film with a thickness of 100 μm and a length of 1000 m was extruded under the molding conditions of a molten resin temperature of 270 ° C. and a T-die width of 500 mm. did. As a result of measuring the refractive index of the produced unstretched film, the refractive index was 1.52. As a result of measuring the saturated water absorption rate of the produced unstretched film by the above-mentioned method, it was 0.01% by weight or less.
Next, the unstretched film having a width of 500 mm was continuously stretched uniaxially at a stretching temperature of 140 ° C. and a stretching ratio of 1.1 times using a roll-type longitudinal stretching machine, so that the orientation axis coincided with the longitudinal direction. The stretched film layer (A) was obtained.

(Production Example 2)
<Production of stretched film layer (B)>
Similarly, the unstretched film having a width of 500 mm obtained in Production Example 1 was continuously uniaxially stretched at a stretching temperature of 140 ° C. and a stretching ratio of 2.0 times using a tenter-type lateral stretching machine, and further, By cutting and removing the portion, a stretched film layer (B) in which the orientation axis coincided with the width direction was obtained.

(Production Example 3)
<Production of stretched film layer (C)>
A stretched film layer (C) was obtained in the same manner as in Example 2 except that the stretch ratio was 5.0.

(Production Example 4)
<Manufacture of polarizer>
A 75 μm thick polyvinyl alcohol film (trade name 9P75R, manufactured by Kuraray Co., Ltd.) was dyed in a 0.3% iodine aqueous solution and then 5 times in a 4% boric acid aqueous solution and a 2% potassium iodide aqueous solution. And then dried at 50 ° C. for 4 minutes to obtain a polarizer.

(Production Example 5)
<Production of aqueous dispersion of water-based urethane resin>
A 2000 ml four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser tube was charged with 317.2 g of 3-methyl-1,5-pentanediol, 174 g of terephthalic acid, and 146 g of adipic acid in a reactor. The esterification reaction was carried out while distilling off the water produced at 200 ° C. while passing nitrogen gas under pressure. When the acid value of the polyester reached 1.0 mgKOH / g, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. The obtained polyester polyol had a hydroxyl value of 56.1 mgKOH / g, an acid value of 0.2 mgKOH / g, and a number average molecular weight (calculated from the hydroxyl value) of 2000.
In a 2000 ml four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a cooling tube, 840 g of the polyester polyol, 119 g of tolylene diisocyanate, and 200 g of methyl ethyl ketone were added and reacted at 75 ° C. for 1 hour while introducing nitrogen. . After completion of the reaction, the mixture was cooled to 60 ° C., 41 g of dimethylolpropionic acid and 25 g of triethylamine were added and reacted at 75 ° C. to obtain a prepolymer solution having a terminal isocyanate group with NCO of 0.5%. Next, this prepolymer was cooled to 40 ° C., 1500 parts of water was added, and emulsification was performed by stirring at high speed with a homomixer. Methyl ethyl ketone was distilled off from the emulsion under heating and reduced pressure to obtain an aqueous dispersion of an aqueous urethane resin having a solid content of 40%.

(Production Example 6)
<Adjustment of coating liquid (A)>
The aqueous dispersion of the water-based urethane resin prepared in Production Example 5 was diluted with water to a solid content of 5% to prepare a coating liquid (A). In addition, a urethane resin layer (A) is formed by coating the coating liquid (A) on a glass substrate, and the pencil hardness and refractive index of the urethane resin layer (A) are measured according to the evaluation method. As a result, the pencil hardness was H and the refractive index was 1.52.

(Production Example 7)
<Adjustment of coating liquid (B)>
By adding 10 g of an aqueous urethane resin dispersion prepared in Production Example 5, 0.4 g of Denacol EX-810 (manufactured by Nagase ChemteX Corp.) and 136 g of water, which is an aqueous epoxy compound, the solid content is 3%. A coating liquid (B) was prepared. In addition, a urethane resin layer (B) is formed by coating the coating liquid (B) on a glass substrate, and the pencil hardness and refractive index of the urethane resin layer (B) are measured according to the evaluation method. As a result, the pencil hardness was 2H and the refractive index was 1.49.

(Production Example 8)
<Adjustment of coating liquid (C)>
By adding 10 g of an aqueous dispersion of an aqueous urethane resin prepared in Production Example 5, 0.2 g of Carbodilite V-02 (manufactured by Nisshinbo Co., Ltd.), which is an aqueous carbodiimide compound, and 125.8 g of water, solid content 3 % Coating liquid (C) was produced. In addition, a urethane resin layer (C) is formed by coating the coating liquid (C) on a glass substrate, and the pencil hardness and refractive index of the urethane resin layer (C) are measured according to the evaluation method. As a result, the pencil hardness was 2H and the refractive index was 1.56.

(Production Example 9)
<Adjustment of coating liquid (D)>
By adding 10 g of an aqueous dispersion of an aqueous urethane resin produced in Production Example 5, 0.08 g of Duranate WB40-100 (manufactured by Asahi Kasei Chemicals Corporation) and 261.9 g of water, which is an aqueous isocyanate compound, the solid content is 1 A 5% coating solution (D) was prepared. The urethane resin layer (D) is formed by applying the coating liquid (D) on the glass substrate, and the pencil hardness and refractive index of the urethane resin layer (D) are measured according to the evaluation method. As a result, the pencil hardness was 2H and the refractive index was 1.54.

(Production Example 10)
<Adjustment of coating liquid (E)>
By adding 5 g of an aqueous dispersion of an aqueous urethane resin prepared in Production Example 5, 2.0 g of a methylated melamine resin MW-30 (manufactured by Sanwa Chemical Co., Ltd.), which is an aqueous amino compound, and 126.3 g of water, and stirring. A coating liquid (E) having a solid content of 3.0% was prepared. In addition, a urethane resin layer (E) is formed by coating the coating liquid (E) on a glass substrate, and the pencil hardness and refractive index of the urethane resin layer (E) are measured according to the evaluation method. As a result, the pencil hardness was 2H and the refractive index was 1.60.

(Production Example 11)
<Adjustment of adhesive liquid>
Goseifamer Z410 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., PVA containing acetoacetyl group) was diluted with water to a solid content of 3% to prepare an adhesive solution.

Example 1
The surface of the stretched film layer (A) produced in Production Example 1 was subjected to a corona treatment device (manufactured by Kasuga Denki Co., Ltd.) with an output of 200 W, a diameter of 1.2 mm wire electrode, an electrode length of 240 mm, and a work electrode distance of 1 Discharge treatment was performed once under the conditions of 0.0 mm and a conveyance speed of 5 m / min. The electrode is a wire electrode and the material is stainless steel. The average water contact angle of the stretched film layer (A) subjected to the discharge treatment was 22 °. Next, the coating liquid (A) produced in Production Example 6 was applied to the discharge-treated surface so that the dry film thickness was 400 nm, and dried at 80 ° C. for 10 minutes to obtain a laminated film 1. As a result of observing the coated surface of the produced laminated film 1, no repelling of the coated surface was observed. The evaluation results of the produced laminated film 1 are shown in Table 1.
Next, after applying the adhesive liquid produced in Production Example 11 to the treated surface of the laminated film 1, it was bonded to the polarizer produced in Production Example 4 using a roll laminator and dried at 70 ° C. for 10 minutes. A polarizing plate 1 was produced. When the peel strength of the produced polarizing plate 1 was measured, it was 420 g / 15 mm width. Moreover, when the abrasion resistance of the produced laminated film 1 was evaluated, no scratch was found on the film surface.

(Example 2)
The surface of the stretched film layer (A) produced in Production Example 1 is output using a corona treatment device (manufactured by Kasuga Electric Co., Ltd.) with an output of 100 W, a wire electrode having a diameter of 1.2 mm, an electrode length of 240 mm, and a work electrode distance of 1 The discharge treatment was performed once under the conditions of 0.5 mm and a conveyance speed of 5 m / min. The electrode is a wire electrode and the material is stainless steel. The average water contact angle of the stretched film layer (A) subjected to the discharge treatment was 28 °. Next, the coating film (B) produced in Production Example 7 was applied to the discharge treated surface so that the dry film thickness was 100 nm, and dried at 80 ° C. for 10 minutes to obtain a laminated film 2. As a result of observing the coated surface of the produced laminated film 2, no repelling of the coated surface was observed. The evaluation results of the produced laminated film 2 are shown in Table 1.
Subsequently, after apply | coating the adhesive liquid produced in the manufacture example 11 to the process surface of the laminated | multilayer film 2, the polarizer produced in the manufacture example 4 is bonded together using a roll laminator, and it dries at 70 degreeC for 10 minutes. A polarizing plate 2 was produced. When the peel strength of the produced polarizing plate 2 was measured, it was 517 g / 15 mm width. Moreover, when the abrasion resistance of the produced laminated film 2 was evaluated, no scratch was found on the film surface.

(Example 3)
The surface of the stretched film layer (B) produced in Production Example 2 was subjected to an output of 1.2 kW, a nitrogen flow rate of 200 L / min, and a conveyance speed of 1 m / min using a remote atmospheric pressure plasma processing apparatus (manufactured by E-Square). Surface treatment was carried out once under conditions. The average water contact angle of the surface-treated stretched film layer (B) was 42 °. Subsequently, the coating liquid (C) produced by the manufacture example 8 was apply | coated to the surface treatment surface so that a dry film thickness might be set to 600 nm, and the laminated film 3 was obtained by drying for 10 minutes at 80 degreeC. As a result of observing the coated surface of the produced laminated film 3, no repelling of the coated surface was observed. The evaluation results of the produced laminated film 3 are shown in Table 1.
Next, after applying the adhesive liquid produced in Production Example 11 to the treated surface of the laminated film 3, it was bonded to the polarizer produced in Production Example 4 using a roll laminator and dried at 70 ° C. for 10 minutes, A polarizing plate 3 was produced. When the peel strength of the produced polarizing plate 3 was measured, it was 559 g / 15 mm width. Moreover, when the abrasion resistance of the produced laminated film 3 was evaluated, no scratch was found on the film surface.

Example 4
The surface of the stretched film layer (C) produced in Production Example 3 was subjected to light of 254 nm (4.9 eV) in nitrogen using a via discharge excimer lamp (manufactured by Ushio Electric) under conditions of an irradiation distance of 1 mm and an irradiation time of 360 seconds. Surface treatment was carried out. The average water contact angle of the surface-treated stretched film layer (C) was 38 °. Subsequently, the coating liquid (D) produced by the manufacture example 9 was apply | coated to the surface treatment surface so that a dry film thickness might be set to 800 nm, and the laminated film 4 was obtained by drying for 10 minutes at 80 degreeC. As a result of observing the coated surface of the produced laminated film 4, no repelling of the coated surface was observed. The evaluation results of the produced laminated film 4 are shown in Table 1.
Subsequently, after apply | coating the adhesive liquid produced in the manufacture example 11 to the process surface of the laminated | multilayer film 4, the polarizer produced in the manufacture example 4 is bonded together using a roll laminator, and it dries at 70 degreeC for 10 minute (s). A polarizing plate 4 was produced. When the peel strength of the produced polarizing plate 4 was measured, it was 496 g / 15 mm width. Moreover, when the abrasion resistance of the produced laminated film 4 was evaluated, no scratch was found on the film surface.

(Comparative Example 1)
A comparative laminated film 1 was obtained in the same manner as in Example 1 except that the corona treatment conditions of Example 1 were changed to an output of 500 W and the number of treatments to 2. In addition, the average water contact angle of the stretched film layer (A) subjected to the discharge treatment was 14 °.
Next, after applying the adhesive liquid produced in Production Example 11 to the treated surface of the comparative laminated film 1, the polarizer produced in Production Example 4 is bonded using a roll laminator and dried at 70 ° C. for 10 minutes. Thus, a comparative polarizing plate 1 was produced. When the peel strength of the produced comparative polarizing plate 1 was measured, it was 180 g / 15 mm width, and a decrease in adhesive strength was observed. Moreover, when the abrasion resistance of the produced comparative laminated film 1 was evaluated, scratches were found on the film surface. As a result of observing scratches on the film surface with a field emission scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.), the urethane resin layer (A) was peeled off from the surface of the stretched film layer (A).

(Comparative Example 2)
A comparative laminated film 2 was obtained in the same manner as in Example 1 except that the corona treatment conditions in Example 1 were changed to 10 W output. In addition, the average water contact angle of the stretched film layer (A) subjected to the discharge treatment was 47 °. As a result of observing the coated surface of the produced comparative laminated film 2, it was observed that remarkable repelling occurred on the coated surface.
Next, after applying the adhesive liquid produced in Production Example 11 to the treated surface of the comparative laminated film 2, the polarizer produced in Production Example 4 is bonded using a roll laminator and dried at 70 ° C. for 10 minutes. Thus, a comparative polarizing plate 2 was produced. When the peel strength of the produced comparative polarizing plate 2 was measured, it was 246 g / 15 mm width, and a decrease in adhesive strength was observed. Moreover, when the abrasion resistance of the produced comparative laminated film 2 was evaluated, scratches were observed on the film surface. As a result of observing scratches on the film surface with a field emission scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.), the urethane resin layer (A) was peeled off from the surface of the stretched film layer (A).

(Comparative Example 3)
The surface of the stretched film layer (A) is corona-treated by the same method as in Comparative Example 1, and the coating solution (E) produced in Production Example 10 is applied to the discharge-treated surface so that the dry film thickness is 400 nm. And the laminated film 3 for a comparison was obtained by drying at 80 degreeC for 10 minute (s). As a result of observing the coated surface of the produced comparative laminated film 3, no repelling of the coated surface was observed. Although the evaluation result of the produced comparative laminated film 3 is described in Table 1, a decrease in the total light transmittance and interference fringes on the surface of the comparative laminated film were remarkably observed. When the peel strength of the produced comparative polarizing plate 3 was measured, it was 147 g / 15 mm width, and a decrease in adhesive strength was observed. Moreover, when the abrasion resistance of the produced comparative laminated film 3 was evaluated, scratches were observed on the film surface. As a result of observing scratches on the film surface with a field emission scanning electron microscope (S-4700, manufactured by Hitachi, Ltd.), the urethane resin layer (E) was peeled from the surface of the stretched film layer (A).

Claims (5)

A method for producing a laminated film having a stretched film layer containing an alicyclic structure-containing polymer and a urethane resin layer,
Forming a stretched film layer having an average surface water contact angle of 20 to 45 degrees;
And a step of applying an aqueous dispersion of a water-based urethane resin to the surface of the stretched film layer.   The average water contact angle of the surface of the stretched film layer is set to 20 to 45 degrees by at least one treatment selected from the group consisting of corona treatment, plasma treatment, and ultraviolet irradiation treatment. The manufacturing method as described.   The manufacturing method according to claim 1, wherein the water-based urethane resin is a self-emulsifying water-based urethane resin.   The manufacturing method according to any one of claims 1 to 3, wherein the aqueous dispersion of the water-based urethane resin contains a crosslinking agent.   The laminated film manufactured by the manufacturing method as described in any one of Claims 1-4.