JP2021017014A - Laminate film and method for producing the same - Google Patents

Abstract

To provide a laminate film that has a hard coat layer provided on a COP-containing base film via an easily-adhesive layer, in which curling is suppressed while ensuring adhesion even after a weather resistant test.SOLUTION: A laminate film 10 has a cycloolefin resin-containing base film 1, an easily-adhesive layer 2 containing a thermosetting aqueous polyolefin and a crosslinker, and a hard coat layer 3 containing an ionizing radiation-curable resin, which are laminated in this order. The easily-adhesive layer 2 has a crosslinkage rate of 23-85%.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated film containing a hard coat layer, which is used as a surface protective film for a polarizing plate of a liquid crystal display device, for example, and a method for producing the laminated film.

In recent years, technological development of liquid crystal display devices and organic EL (Electro-Luminescence) display devices has progressed, and not only large display devices for signboards but also display devices having curved surfaces and high design have been developed. There is. The latter display device is being considered to be installed on a pillar in a station or a public facility, or to be used as a substitute for a measuring device (for example, a tachometer) in a vehicle.

By the way, a liquid crystal display device is configured by sandwiching a liquid crystal layer between a pair of polarizing plates. Further, in the organic EL display device, a polarizing plate (circular polarizing plate) for preventing reflection of external light may be used. These polarizing plates include an optical film that protects the polarizer. In addition to being a thin film, the optical film is required to have moisture resistance in consideration of changes in the usage environment (for example, changes in humidity). Therefore, as the optical film, a cycloolefin polymer (COP) film having low moisture permeability is being studied.

On the other hand, when the display device is used for in-vehicle use, it is essential that the optical film has high scratch resistance and impact resistance in consideration of human safety. Therefore, a hard coat is applied on the base film. Processing to apply a layer or the like is generally performed. However, since a COP film having low moisture permeability generally has few chemical reaction sites, when the COP film is used as a base film, the bond with the hard coat layer is weak and it is necessary to improve the adhesion. Was there.

Regarding this point, for example, in Patent Document 1, by interposing an easy-adhesion layer between the COP film and the hard coat layer, the initial adhesion and the time-dependent adhesion between the COP film and the hard coat layer are improved. .. Regarding the adhesion over time, a COP film with a hard coat layer (also referred to as “laminated film” here) was placed in a sample hanger in a blower dryer at a temperature of 90 ° C. and stored for 30 days, and then JIS- It is evaluated by performing a peeling test by cross-cut according to K5600-5-6.

Japanese Patent No. 6453689

By the way, when the display device is used for in-vehicle use, the usage environment is not only an environment that causes humidity fluctuations but also an environment that is exposed to light (for example, ultraviolet rays). High weather resistance (performance to ensure adhesion even after long-term irradiation with ultraviolet rays) and weather curl resistance (performance to suppress curl due to curing shrinkage even after long-term irradiation with ultraviolet rays) are required. In Patent Document 1, as described above, the adhesion due to heat resistance over time has been studied, but the adhesion and curl due to ultraviolet irradiation over time have not been studied at all. Therefore, it cannot always be said that the laminated film of Patent Document 1 can suppress curl while ensuring adhesion after performing a weather resistance test by irradiation with ultraviolet rays for a long time.

The present invention has been made to solve the above problems, and an object of the present invention is to irradiate a base film containing COP with an ultraviolet irradiation for a long time in a configuration in which a hard coat layer is laminated via an easy-adhesion layer. It is an object of the present invention to provide a laminated film capable of suppressing curling while ensuring adhesion even after performing a weather resistance test according to the above, and a method for producing the laminated film.

The laminated film on one side of the present invention is obtained by laminating a base film containing a cycloolefin resin, an easily adhesive layer containing a thermosetting aqueous polyolefin and a cross-linking agent, and a hard coat layer containing an ionizing radiation curable resin. The cross-linking rate of the easy-adhesion layer is 23 to 85%.

The method for producing the other side surface of the present invention is the method for producing the laminated film, which comprises an easy-adhesive layer forming step of forming the easy-adhesive layer on the base film and the hard coating on the easy-adhesive layer. In the hard coat layer forming step, which includes a hard coat layer forming step of forming a layer, when the cross-linking rate of the easy-adhesive layer is 10 to 80%, the ionization radiation curable type is placed on the easy-adhesive layer. A hard coat layer forming material containing a resin is applied, and then the ionized radiation curable resin is cured by drying and irradiation with ionizing radiation to form the hard coat layer and the cross-linking rate of the easily adhesive layer is 23. Adjust to ~ 85%.

In a configuration in which a hard coat layer is laminated on a base film containing COP via an easy-adhesive layer, the easy-adhesive layer contains a cross-linking agent and the cross-linking rate is within a predetermined range. When a weather resistance test was carried out by irradiating (for example, ultraviolet rays) for a long time, the unreacted portion of the easy-adhesive layer caused a cross-linking reaction, and the resin structure of the hard coat layer was formed near the interface with the hard coat layer. Intertwined. As a result, the adhesion between the easy-adhesion layer and the hard coat layer can be ensured even after the weather resistance test is performed. Further, since the cross-linking rate of the easy-adhesive layer is within a predetermined range, it is possible to suppress excessive curing shrinkage of the easy-adhesive layer even after performing a weather resistance test, thereby suppressing curling of the laminated film. it can.

It is sectional drawing which shows the schematic structure of the laminated film which concerns on embodiment of this invention. It is explanatory drawing which shows typically the model of the molecule at the interface between the easy-adhesion layer and the hard coat layer contained in the laminated film. It is a flowchart which shows the flow of the manufacturing process of the laminated film.

An embodiment of the present invention will be described below with reference to the drawings. In this specification, when the numerical range is expressed as A to B, the numerical range includes the values of the lower limit A and the upper limit B.

[Laminated film]
FIG. 1 is a cross-sectional view showing the configuration of the laminated film 10 of the present embodiment. The laminated film 10 includes a base film 1, an easy-adhesion layer 2, and a hard coat layer 3 in this laminated order.
The base film 1 contains a cycloolefin resin (COP). The easy-adhesion layer 2 contains a thermosetting water-based polyolefin and a cross-linking agent. The hard coat layer 3 contains an ionizing radiation curable resin such as an ultraviolet curable resin.

FIG. 2 schematically shows a molecular model at the interface between the easy-adhesion layer 2 and the hard coat layer 3. In the present embodiment, the easy-adhesion layer 2 contains a cross-linking agent, and the cross-linking rate thereof is set to 23 to 85%. As a result, when the laminated film 10 is subjected to a weather resistance test in which ultraviolet rays as ionizing radiation are irradiated for a long time, a portion of the easy-adhesion layer 2 that has not been crosslinked causes a crosslinking reaction. That is, the cross-linking agent reacts with the functional groups of the easy-adhesion layer 2 one by one due to the heat applied during the weather resistance test. Then, near the interface between the easy-adhesive layer 2 and the hard coat layer 3, the cross-linked structure of the easy-adhesive layer 2 is entangled with the network structure of the hard coat layer 3 (see the state of “with cross-linking agent” in FIG. 2). Three-dimensional strength is given at the interface. As a result, the adhesion between the easy-adhesion layer 2 and the hard coat layer 3 can be ensured even after the weather resistance test is performed.

Further, since the easy-adhesion layer 2 contains an aqueous polyolefin, the interaction (intermolecular force) between the olefin portion of the base film 1 containing COP and the water-based polyolefin of the easy-adhesion layer 2 makes it easy with the base film 1. Adhesion with the adhesive layer 2 is ensured. Therefore, even after the weather resistance test, the adhesion between the base film 1 and the hard coat layer 3 can be ensured via the easy-adhesion layer 2. Further, since the water-based polyolefin of the easy-adhesive layer 2 is thermosetting, the easy-adhesive layer 2 can be easily formed by applying the material constituting the easy-adhesive layer 2 on the base film 1 and drying it. Can be done.

Further, when the cross-linking rate of the easy-adhesive layer 2 is less than 23%, there are many unreacted portions of the cross-linking agent, so that the easy-adhesive layer 2 is easily cured and shrunk by the heat when the weather resistance test is performed. 10 is easy to curl. On the other hand, when the cross-linking rate of the easy-adhesive layer 2 exceeds 85%, there are few unreacted portions of the cross-linking agent. , It becomes difficult to ensure the effect of improving the adhesion between the easy-adhesion layer 2 and the hard coat layer 3 by the cross-linking reaction.

Therefore, since the cross-linking rate of the easy-adhesive layer 2 is set to 23 to 85%, the cross-linking reaction of the cross-linking agent is fully utilized even after the weather resistance test is performed on the laminated film 10, and over time. The effect of improving the adhesiveness of the laminated film 10 can be ensured, and excessive curing shrinkage of the easy-adhesion layer 2 can be suppressed to suppress curling of the laminated film 10. In particular, when the cross-linking rate of the easy-adhesion layer 2 is 26 to 78%, the effect of improving the adhesion after the weather resistance test and the effect of suppressing the curl of the laminated film 10 can be surely obtained. From the viewpoint of further enhancing those effects, it is desirable that the cross-linking rate of the easy-adhesion layer is 35 to 46%.

By the way, the cross-linking agent can be appropriately selected from carbodiimide-based, oxazoline-based, aziridine-based and the like, and is particularly preferably carbodiimide-based or oxazoline-based. Carbodiimide-based or oxazoline-based cross-linking agents form an amide ester structure after cross-linking. When the weather resistance test is performed, a chemical interaction acts between the amide ester structure in the easy-adhesion layer 2 and the polar group of the hard coat layer 3, so that the adhesion after the weather resistance test can be further improved. ..

It is desirable that the hard coat layer 3 contains urethane acrylate as an ionizing radiation curable resin. In this case, when the weather resistance test is performed, a chemical interaction acts between the urethane bonding portion of the urethane acrylate and the cross-linking agent of the easy-adhesion layer 2, so that the easy-adhesion layer 2 and the hard coat layer 3 adhere to each other. The sex can be further improved.

[Manufacturing method of laminated film]
The laminated film 10 having the above structure can be manufactured as follows. FIG. 3 is a flowchart showing a manufacturing process of the laminated film 10 of the present embodiment. First, the base film 1 containing COP is prepared (S1; base film preparation step). Next, the easy-adhesion layer 2 is formed on the base film 1 (S2; easy-adhesion layer forming step). Then, the hard coat layer 3 is formed on the easy-adhesion layer 2 (S3; hard coat layer forming step). In this S3, when the cross-linking rate of the easy-adhesion layer 2 is 10 to 80%, a hard coat layer forming material containing an ionizing radiation curable resin (for example, an ultraviolet curable resin) is applied onto the easy-adhesion layer 2. After that, the ionizing radiation curable resin is cured by drying and irradiation with ionizing radiation (for example, ultraviolet rays) to form a hard coat layer and adjust the cross-linking rate of the easy-adhesion layer 2 to 23 to 85%.

As described above, since the cross-linking rate of the easy-adhesive layer 2 at the time of applying the hard coat layer forming material is 10 to 80%, the cross-linking is performed by drying at the time of forming the hard coat layer 3 and heating at the time of irradiation with ionizing radiation. By further advancing the reaction, it becomes possible to realize the above-mentioned cross-linking rate of the easy-adhesion layer 2 of 23 to 85%.

That is, if the cross-linking rate at the time of coating is less than 10%, it is difficult to raise the cross-linking rate of the easy-adhesion layer 2 to 23% due to the cross-linking reaction by drying at the time of forming the hard coat layer 3 and heating at the time of ultraviolet irradiation. Become. Therefore, in this case, since there are many unreacted portions of the cross-linking agent, the easy-adhesive layer 2 is excessively cured and shrunk when the weather resistance test is performed, and the laminated film 10 tends to curl. On the other hand, if the cross-linking rate at the time of coating exceeds 80%, the cross-linking reaction due to drying during formation of the hard coat layer 3 and heating during ultraviolet irradiation proceeds too much, and the cross-linking rate of the easy-adhesive layer 2 exceeds 85%. It will be easier. As described above, when the cross-linking rate of the easy-adhesion layer 2 exceeds 85%, it becomes difficult to ensure the effect of improving the adhesion when the weather resistance test is performed. The desirable range of the cross-linking rate of the easy-adhesion layer 2 at the time of coating the hard coat layer forming material is 15 to 75%.

Here, it is desirable that the above-mentioned hard coat layer forming material contains a solvent, the solvent contains alcohols or glycol ethers, and the mass ratio of alcohols or glycol ethers to the whole solvent is 20% or more. .. When the above mass ratio is satisfied, excessive penetration of the solvent into the easy-adhesion layer 2 containing polyolefin can be suppressed, so that the adhesion at the interface between the easy-adhesion layer 2 and the hard coat layer 3 is surely secured, and the weather resistance is maintained. The adhesion after the test can be further improved.

[Base film]
Examples of the cycloolefin resin contained in the base film include the following (co) polymers.

In the formula, R ^{1 to} R ⁴ are independently hydrogen atom, hydrocarbon group, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amide group, imide group, silyl group or polar group (ie, It is a hydrocarbon group substituted with a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, or a silyl group). However, in R ^{1 to} R ⁴ , two or more of them may be bonded to each other to form an unsaturated bond, a monocyclic ring or a polycyclic ring, and the monocyclic or polycyclic ring has a double bond. Alternatively, an aromatic ring may be formed. An alkylidene group may be formed by R ¹ and R ² , or by R ³ and R ⁴ . p and m are integers greater than or equal to 0.

In the above general formula (1), R ¹ and R ³ are hydrogen atoms or hydrocarbon groups having 1 to 10 carbon atoms, more preferably 1 to 4, particularly preferably 1 or 2. R ² and R ⁴ are hydrogen atoms or monovalent organic groups, and at least one of R ² and R ⁴ represents a polar group having a polarity other than a hydrogen atom and a hydrocarbon group, and m is 0 to 3. The integer, p, is an integer of 0 to 3, more preferably m + p = 0 to 4, still more preferably 0 to 2, particularly preferably m = 1, p = 0. The specific monomer having m = 1 and p = 0 is preferable in that the obtained cycloolefin resin has a high glass transition temperature and excellent mechanical strength.

Examples of the polar group of the specific monomer include a carboxy group, a hydroxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group, a cyano group and the like, and these polar groups include a linking group such as a methylene group. They may be combined via. Further, a hydrocarbon group to which a polar divalent organic group such as a carbonyl group, an ether group, a silyl ether group, a thioether group and an imino group is bonded as a linking group is also mentioned as a polar group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group or an aryloxycarbonyl group is preferable, and an alkoxycarbonyl group or an aryloxycarbonyl group is particularly preferable.

Further, the monomer in which at least one of R ² and R ⁴ is a polar group represented by the formula − (CH ₂ ) _n COOR is obtained from a cycloolefin resin having a high glass transition temperature, low hygroscopicity, and various materials. It is preferable in that it has excellent adhesion. In the above formula for the specific polar group, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4, particularly preferably 1 to 2, an alkyl group.

Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. The number of carbon atoms of the cycloolefin is preferably in the range of 4 to 20, and more preferably 5 to 12.

In the present embodiment, the cycloolefin resin may be used alone or in combination of two or more.

The preferred molecular weight of the cycloolefin resin of the present embodiment is 0.2 to 5 dl / g at an intrinsic viscosity [η] inh, more preferably 0.3 to 3 dl / g, and particularly preferably 0.4 to 1.5 dl / g. The polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 8,000 to 100,000, more preferably 1,000 to 80,000, particularly preferably 12,000 to 50,000, and the weight average molecular weight (Mw). Is preferably in the range of 20000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 40,000 to 200,000.

When the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance and mechanical properties of the cycloolefin resin and the cycloolefin film of the present embodiment can be obtained. The moldability is improved.

The glass transition temperature (Tg) of the cycloolefin resin of the present embodiment is usually in the range of 110 ° C. or higher, preferably 110 to 350 ° C., more preferably 120 to 250 ° C., and particularly preferably 120 to 220 ° C. .. A case where the Tg is 110 ° C. or higher is preferable because deformation is unlikely to occur due to use under high temperature conditions or secondary processing such as coating and printing. On the other hand, when the Tg is 350 ° C. or lower, it is possible to avoid the case where the molding process becomes difficult and suppress the possibility that the resin is deteriorated by the heat during the molding process.

For the cycloolefin resin, for example, a specific hydrocarbon-based resin described in JP-A-9-221577 and JP-A-10-287732, or a known heat, as long as the effects of the present embodiment are not impaired. Plastic resins, thermoplastic elastomers, rubber polymers, organic fine particles, inorganic fine particles, etc. may be blended, and specific wavelength dispersants, sugar ester compounds, antioxidants, peeling accelerators, rubber particles, plasticizers, ultraviolet rays, etc. may be blended. It may contain an additive such as an absorbent.

Further, as the cycloolefin resin, a commercially available product can be preferably used. Commercially available products are, for example, sold by JSR Corporation under the trade names of Arton (registered trademark) G, Arton F, Arton R, and Arton RX, and Zeonor (registered) by Nippon Zeon Corporation. Trademarks) ZF14, ZF16, Zeonex (registered trademark) 250 or Zeonex 280 are commercially available, and these can be used.

[Easy adhesive layer]
The easy-adhesion layer preferably contains a mixture of a polyolefin resin and a fibrous resin. In particular, the easy-adhesion layer preferably contains a mixture of water-based resins. For example, when the easy-adhesive layer is designed with a solvent-based resin, the polyolefin-based resin, which is the main binder, has excellent solubility in an aromatic hydrocarbon-based solvent, but the base film is easily dissolved by the solvent, which makes it easy. It is difficult to form an adhesive layer. Further, the polyolefin resin is a very flexible coating film, and the one in which the hard coating layer of the coating film is formed on the easy-adhesion layer has a large shrinkage difference between the easy-adhesion layer and the hard coat layer. There is a problem that cracks are likely to occur below. As a crack prevention measure, it is effective to harden the coating film of the easy-adhesion layer to bring it closer to the hardness of the coating film of the hard coat layer, but since polyolefin-based resins are inferior in compatibility with other resins, resin selection is necessary. There is a difficult problem.

The easy-adhesive layer is composed of a mixture of a thermosetting aqueous polyolefin resin and an aqueous other component resin. Therefore, when the easy-adhesion layer is applied onto the base film, the base film is not eroded and stable adhesion to the base film can be ensured. In the present embodiment, since it is effective to use the fibrous resin as the other resin to be mixed with the polyolefin resin, the fibrous resin is selected.

The polyolefin-based resin constituting the easy-adhesion layer is a resin blended for the purpose of imparting adhesion between the base film and the hard coat layer. As a result of examining a resin for an easy-adhesion layer having excellent adhesion to both the base film and the hard coat layer, it was found that a polyolefin-based resin having excellent flexibility is suitable.

The polyolefin-based resin used for the easy-adhesion layer is not particularly limited, but two or more kinds of monomers such as an ethylene-propylene copolymer and a propylene-butene copolymer have a common weight as those having excellent adhesion to the base film. Those constituting a coalescence are preferable, and those containing a propylene monomer in the copolymer are particularly preferable. Examples of such polyolefin-based resins include commercially available arrow bases (trade name: manufactured by Unitika Ltd.) and aurolen (trade name: manufactured by Nippon Paper Industries, Ltd.).

Since this polyolefin-based resin is a resin having excellent flexibility, there is a problem that it is easy to crimp when the film is wound by forming an easy-adhesion layer. Therefore, from the viewpoint of preventing blocking between films, it is possible to prevent pressure bonding by blending a fibrous resin with high hardness and inorganic or organic fine particles in the easy-adhesion layer, or by attaching a protective film to the back surface of the base film. preferable.

When blending inorganic or organic fine particles, the blending amount (parts by weight) shall be in the range of resin / inorganic or organic fine particles forming the easy-adhesion layer = 99.5 / 0.5 to 95.0 / 5.0. Is preferable. If the blending amount of the fine particles exceeds 5.0 parts by weight, the transparency and the adhesion to the cycloolefin film are lowered, which is not preferable. On the other hand, if the blending amount of the fine particles is less than 0.5 parts by weight, there is a concern that a sufficient effect may not be exhibited.

Examples of the inorganic fine particles include fine particles such as alumina, zinc oxide, silica, titanium oxide, and cerium oxide, and examples of the organic fine particles include fine particles such as acrylic, melamine / formaldehyde condensate, polyethylene, styrene acrylic, and polyester. It can be exemplified. As the particle size, for example, it is preferable to use fine particles having a particle size of 0.05 μm to 1.00 μm. If the particle size is less than 0.05 μm, the crimp prevention effect is low, which is not preferable. On the other hand, if the particle size exceeds 1.00 μm, no further crimp-preventing effect can be obtained, the cost becomes high, the external haze becomes high, and the transparency tends to decrease, which is not preferable.

The fibrous resin contained in the easy-adhesion layer refers to a resin manufactured based on plant fiber such as cotton and pulp, and is a methyl cellulose resin, an ethyl cellulose resin, a propyl cellulose resin, and a hydroxypropyl methyl cellulose resin. , Hydroxyethyl cellulose-based resin, hydroxypropyl cellulose-based resin and the like can be used. Among the fibrous resins, those having a substituent having two or more carbon atoms introduced into the cellulose molecule are preferable as those capable of obtaining thermal stability by complicated three-dimensional structural entanglement, and the glucose ring of the cellulose is preferable. The average number of moles of substituents added per unit is preferably 0.1 to 0.5, more preferably 0.15 to 0.5. Specific examples of fibrous resins include commercially available Metrose 65SH-400 resin (trade name) (hydroxypropylmethyl cellulose resin: manufactured by Shin-Etsu Chemical Co., Ltd.) and SP500 resin (trade name) (hydroxyethyl cellulose resin: Daicel Fine Chem Ltd.). (Made by company), etc.

The blending ratio (parts by weight) of the polyolefin resin and the fibrous resin contained in the easy-adhesion layer is preferably in the range of 99/1 to 90/10. When the blending ratio of the polyolefin resin exceeds 99 parts by weight, the easily adhesive layer formed is soft and easily stretches. Therefore, due to the shrinkage difference from the hard coat layer that does not stretch hard, it is stored under heat resistant conditions (for example, at 100 ° C. for 5 minutes). ), There is a problem that cracks are likely to occur, and there is a problem that the coating film hardness (pencil hardness) is likely to decrease when the hard coat layer is formed on the easy-adhesive layer. On the other hand, when the blending ratio of the polyolefin resin is less than 90 parts by weight, the shrinkage difference between the easy-adhesion layer and the hard coat layer becomes small, and cracks do not occur under heat-resistant conditions, which is good. Adhesion with the material film may decrease.

The thickness of the easy-adhesion layer is preferably 0.1 μm or more and 2 μm or less, but more preferably 0.3 μm to 1 μm from the viewpoint of stability of initial adhesion.

A leveling agent can be blended in the easy-adhesion layer for the purpose of improving coatability, and known leveling agents such as fluorine-based, acrylic-based, siloxane-based, and adducts or mixtures thereof can be used. is there. For example, the leveling material can be blended in the range of 0.03 parts by weight to 3.0 parts by weight with respect to 100 parts by weight of the resin component of the easy-adhesion layer.

A benzotriazole-based ultraviolet absorber and a benzophenone-based ultraviolet absorber can be blended in the easy-adhesion layer for the purpose of imparting light adhesion. The blending amount of the ultraviolet absorber is preferably 0.05 parts by weight to 10.0 parts by weight, particularly preferably 1.0 parts by weight to 5. parts by weight with respect to 100 parts by weight of the resin component of the easy-adhesion layer. It is 0 parts by weight.

As other additives to be added to the easy-adhesion layer, antifoaming agents, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc. are blended as necessary within the range that does not impair the effects of the present embodiment. You may.

For the easy-adhesion layer, in addition to the above-mentioned polyolefin resin and the above-mentioned fibrous resin, other additives and the like are dissolved in appropriate water or water / organic solvent, and a dispersed paint is applied onto the base film and dried. It is formed. As described above, the easy-adhesion layer contains a mixture of water-based resins, but when the paint is applied on the base film, it does not contain repellents, streaks, etc. and has excellent coatability, and the easy-adhesion applied. From the viewpoint of improving the drying property of the layer, an organic solvent that can be mixed with water may be added to the paint. In this case, the organic solvent is a solvent that can be mixed with water, can be appropriately selected depending on the solubility or dispersibility of the resin, and can uniformly dissolve or disperse at least the solid content (resin and other additives). It is preferable to use an organic solvent having a boiling point of 50 ° C. to 160 ° C. from the viewpoint of the presence, workability at the time of coating, and dryness. As such a solvent, for example, a known organic solvent such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, methylethylketone, dimethylformamide and the like can be used in combination with water.

As a method of applying the paint for the easy-adhesion layer on the base film, gravure coating, microgravure coating, fountain bar coating, slide die coating, slot die coating, screen printing method, spray coating method, etc. A known coating method can be used. The paint applied on the base film is usually dried at a temperature of about 50 to 120 ° C. to remove the solvent, and then cured by applying thermal energy or external energy such as ultraviolet rays or electron beams to form a coating film. Form.

(Crosslinking agent)
The easy-adhesion layer contains a cross-linking agent. Various known cross-linking agents can be used, and examples thereof include oxazoline compounds, melamine compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and silane coupling compounds. Among these, when a functional layer (hard heart layer) is provided on the coating layer (easy-adhesion layer), an oxazoline-based compound is preferably used from the viewpoint of improving durability and adhesion. Further, the melamine compound is preferably used from the viewpoint of preventing the precipitation of the ester cyclic trimer on the film surface by heating and improving the durability and coatability of the coating layer.

The oxazoline-based compound is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and it can be prepared by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with another monomer. Additionally polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer, and is, for example, an alkyl (meth) acrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. , N-Butyl group, Isobutyl group, t-Butyl group, 2-Ethylhexyl group, Cyclone group) and other (meth) acrylic acid esters; acrylic acid, methacrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, Unsaturated carboxylic acids such as styrene sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth) acrylamide, N-alkyl (Meta) acrylamide, N, N-dialkyl (meth) acrylamide, (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2- Unsaturated amides such as ethylhexyl group, cyclohexyl group, etc .; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Vinyl chloride, chloride Halogen-containing α, β-unsaturated monomers such as vinylidene and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, etc. can be mentioned, and one or two of these can be mentioned. The above monomers can be used.

The amount of oxazoline groups of the oxazoline-based compound contained in the coating liquid forming the coating layer (easy-adhesion layer) constituting the laminated film is usually 0.5 to 10 mmol / g, preferably 3 to 9 mmol / g, more preferably. Is in the range of 5-8 mmol / g. By using it in the above range, the durability of the coating film is improved.

A melamine compound is a compound having a melamine structure in the compound, for example, an alkylolated melamine derivative, a compound obtained by reacting an alcoholylated melamine derivative with an alcohol to partially or completely etherify, and these. A mixture can be used. As the alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Further, the melamine compound may be either a monomer or a multimer of a dimer or more, or a mixture thereof may be used. Further, a melamine that is copolymerized with urea or the like can be used, or a catalyst can be used to increase the reactivity of the melamine compound.

The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include a condensate of epichlorohydrin and an ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and other hydroxyl groups and amino groups. There are polyepoxide compounds, diepoxide compounds, monoepoxide compounds, glycidylamine compounds and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyltris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane. Examples of the polyglycidyl ether and the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, Polytetramethylene glycol diglycidyl ether, Monoepoxy compounds include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenylglycidyl ether, glycidylamine compounds N, N, N, N- Examples thereof include tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

The isocyanate-based compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of the isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyldiisocyanate, phenylenedi isocyanate and naphthalene diisocyanate, and aliphatic isocyanates having an aromatic ring such as α, α, α and α-tetramethylxylylene diisocyanate. Fats such as aliphatic isocyanates such as isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate and hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylenebis (4-cyclohexylisocyanate) and isopropyridene dicyclohexyldiisocyanate. Examples thereof include cyclic isocyanate. In addition, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimides of these isocyanates can also be mentioned. These may be used alone or in combination of two or more. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

When used in the state of blocked isocyanate, the blocking agent includes, for example, phenolic compounds such as heavy sulfites, phenol, cresol and ethylphenol, and alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol and ethanol. Compounds, active methylene compounds such as methyl isobutanoyl acetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Examples include lactam compounds, amine compounds such as diphenylaniline, aniline, and ethyleneimine, acid amide compounds such as acetoanilide and acetate amide, oxime compounds such as formaldehyde, acetoaldoxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime. These may be used alone or in combination of two or more.

The isocyanate compound may be used alone, or may be used as a mixture or a bond with various polymers. In terms of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

A carbodiimide-based compound is a compound having a carbodiimide structure, which is a compound having one or more carbodiimide structures in the molecule, but has two or more carbodiimide structures in the molecule for better adhesion or the like. The polycarbodiimide-based compound having is more preferable.

The carbodiimide-based compound can be synthesized by a conventionally known technique, and a condensation reaction of a diisocyanate compound is generally used. The diisocyanate compound is not particularly limited, and any aromatic or aliphatic type can be used. Specifically, toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylenedi isocyanate, naphthalenediocyanate, hexamethylene. Examples thereof include diisocyanate, trimethylhexamethylene diisocyanate, cyclohexanediisocyanate, methylcyclohexanediisocyanate, isophorone diisocyanate, dicyclohexyldiisocyanate and dicyclohexylmethane diisocyanate.

The content of the carbodiimide group contained in the carbodiimide-based compound is a carbodiimide equivalent (weight [g] of the carbodiimide compound for giving 1 mol of the carbodiimide group), and is usually 100 to 1000, preferably 250 to 700, and more preferably 300. It is in the range of ~ 500. By using in the above range, the durability of the coating film is improved.

Further, in order to improve the water solubility and water dispersibility of the polycarbodiimide-based compound, a surfactant may be added, and the polyalkylene oxide and the quaternary ammonium of the dialkylamino alcohol may be added as long as the effects of the present embodiment are not lost. Hydrophilic monomers such as salts and hydroxyalkyl sulfonates may be added and used.

In addition, an aziridine-based compound can also be used as the cross-linking agent. The aziridine-based compound is a compound having an aziridine group in the molecule.

Among the above, it is desirable as a cross-linking agent from the viewpoint that a carbodiimide-based compound or an oxazoline-based compound interacts with the polar group of the hard coat layer 3 to improve the weather adhesion.

[Hard coat layer]
The hard coat layer contains at least silica fine particles having an aspect ratio of 2 to 40 and a curable resin binder, and is obtained by curing the curable resin binder. The film thickness of the hard coat layer is preferably in the range of 2 to 40 μm, and more preferably in the range of 3 to 15 μm from the viewpoint of excellent scratch resistance, pencil hardness and other mechanical film strength.

(Curable resin binder)
The curable resin binder contains the curable resin as a main component, that is, in the highest proportion. The curable resin is not particularly limited, but an active ray-curable resin (also referred to as an ionizing radiation curable resin) is preferable because it is excellent in mechanical film strength such as scratch resistance and pencil hardness. That is, it is preferable that the resin binder contains a resin as a main component, which is cured through a cross-linking reaction by irradiation with active rays (also referred to as active energy rays or ionizing radiation) such as ultraviolet rays and electron beams.

As the active ray-curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active ray-curable resin layer is formed by curing by irradiating with an active ray such as ultraviolet rays or an electron beam. ..

Typical examples of the active ray-curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin that is cured by irradiation with ultraviolet rays is particularly preferable because it has excellent mechanical film strength. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, and an ultraviolet curable epoxy acrylate described in JP-A-2014-224920. Resins, ultraviolet curable polyol acrylate resins, ultraviolet curable epoxy resins and the like are preferably used, and among them, ultraviolet curable acrylate resins or ultraviolet curable urethane acrylate resins are preferable.

As the ultraviolet curable acrylate resin, polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or metachloroyloxy groups in the molecule.

Examples of the monomer of the polyfunctional acrylate include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, dimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerin triacrylate , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, Neopentyl glycol dimethacrylate, Trimethylolpropane Trimethacrylate, Trimethylolethanetrimethacrylate, Tetramethylolmethanetrimethacrylate, Tetramethylolmethanetetramethacrylate, Pentaglycerol trimethacrylate, Pentaerythritol dimethacrylate, Pentaerythritol trimethacrylate, Pentaerythritol tetra Preferable examples thereof include methacrylate, glycerin trimethylolpropane, dipentaerythritol trimethylolpropane, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, and active energy ray-curable isocyanurate derivatives.

Moreover, you may use a monofunctional acrylate. Examples of the monofunctional acrylate include isobolonyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethylcarbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, and behenyl. Examples thereof include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nihon Kasei Kogyo Co., Ltd., Shin Nakamura Chemical Industry Co., Ltd., Osaka Organic Chemical Industry Co., Ltd. and the like.

When a monofunctional acrylate is used, it is preferably contained in a polyfunctional acrylate: monofunctional acrylate = 80:20 to 100: 0 in terms of the content mass ratio of the polyfunctional acrylate to the monofunctional acrylate.

As the ultraviolet curable urethane acrylate-based resin, for example, a hydroxy group-containing compound such as an alcohol, a polyol, and / or a hydroxy group-containing acrylate is reacted with an isocyanate, or, if necessary, a polyurethane obtained by these reactions. It is obtained by esterifying the compound with (meth) acrylic acid.

More specifically, it is an addition reaction product of polyisocyanate and an acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 4,4-diphenyldiisocyanate, 1,5-naphthalenediisocyanate, and 4,4-diphenylmethane. A compound having two isocyanate groups bonded to an alicyclic hydrocarbon such as aromatic isocyanate such as diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornan diisocyanate, and 1,4-cyclohexanediisocyanate (hereinafter abbreviated as alicyclic diisocyanate). , Trimethylene diisocyanate, hexamethylene diisocyanate and other compounds having two isocyanate groups bonded to aliphatic hydrocarbons (hereinafter abbreviated as aliphatic diisocyanate), phenylenediocyanate, toluene diisocyanate and other aromatic diisocyanates, xylylene diisocyanate and the like. Aromatic aliphatic diisocyanates and the like can be mentioned.

These polyisocyanates can be used alone or in combination of two or more, and are preferably an aliphatic diisocyanate or an alicyclic diisocyanate. Of these, isophorone diisocyanate, norbornane diisocyanate, toluene diisocyanate and hexamethylene diisocyanate are preferable. Examples of the acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth). Examples include polyacrylates of polyvalent hydroxy group-containing compounds such as acrylates, and examples thereof include additions of these polyacrylates and ε-caprolactone, additions of these polyacrylates and alkylene oxides, and epoxy acrylates. Be done. An acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule can be used alone or in combination of two or more.

Further, among acrylates having one hydroxy group and one or more (meth) acryloyl groups in one molecule, acrylates having one hydroxy group and 3 to 5 (meth) acryloyl groups in one molecule are preferable. Examples of such an acrylate include pentaerythritol triacrylate and dipentaerythritol pentaacrylate.

Specific products of the ultraviolet curable urethane acrylate resin include Shikou UV-1700B, UV-6300B, UV-7600B, UV-7630B, UV-7640B, Kyoeisha Chemical Co., Ltd., manufactured by Nippon Synthetic Chemical Co., Ltd. Made by the company, UA-306H, UA-306T, UA-306I, UA-510H, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., NK oligo UA-1100H, NK oligo UA-53H, NK oligo UA-33H, NK oligo UA-15HA And so on.

As the curable resin used for the hard coat layer, a general-purpose resin material can be used as described above, but from the viewpoint of improving the adhesion to the easy-adhesion layer and improving the adhesion after the weather resistance test. It is desirable to use urethane acrylate.

(solvent)
The hard coat layer forming material for forming the hard coat layer contains a solvent in addition to the above-mentioned ionizing radiation curable resin (curable resin). Solvents include alcohols (ethanol, methanol, butanol, n-propyl alcohol, isopropyl alcohol, diacetone alcohol), hydrocarbons (toluene, xylene, benzene, cyclohexane), glycol ethers (propylene glycol monomethyl ether, propylene glycol). (Monopropyl ether, ethylene glycol monopropyl ether, etc.) and the like can be preferably used.

As the other solvent, it is preferable to use ketones or esters. Examples of the ketones include methyl ethyl ketone, acetone, cyclohexanone, methyl isobutyl ketone and the like. Examples of the esters include, but are not limited to, methyl acetate, ethyl acetate, butyl acetate, propyl acetate and the like. Ketones or esters can be used alone or in combination with alcohols and the like.

Above all, it is better not to dissolve the easy-adhesion layer from the viewpoint of curl and adhesion, and in this respect, it is preferable to use alcohols or glucol ethers as the solvent. At this time, the mass ratio of alcohols or glucol ethers to the entire solvent is 20% or more to suppress excessive permeation of the solvent into the easy-adhesion layer and further improve the adhesion after the weather resistance test. It is desirable in that it can be done.

The amount of the hard coat layer forming material containing the resin and the solvent applied is preferably 0.1 to 40 μm, preferably 0.5 to 30 μm as the wet film thickness. The dry film thickness is preferably 0.1 to 30 μm, preferably 1 to 20 μm, and particularly preferably 1 to 5 μm.

(Additive)
The hard coat layer forming material can contain various additives as long as the purpose and effect of the present embodiment are not impaired. Additives include epoxy resin, polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based oligomer, silicone. Polymers or oligomers such as system oligomers and polysulfide oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiators; leveling agents; wettability improvers; surfactants ; Plastics; UV absorbers; Inorganic fillers; Pigments; Dyes and the like.

The above additive is usually 0 to 10 parts by weight, preferably 0 to 5 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component.

(Photopolymerization initiator)
The hard coat layer forming material can include a photopolymerization initiator. The photopolymerization initiator is appropriately selected by the active energy ray. When curing by ultraviolet rays or visible light, a photopolymerization initiator that cleaves ultraviolet rays or visible light is used. The photopolymerization initiator may be used alone, but when a plurality of photopolymerization initiators are mixed and used, the curing rate and curability can be adjusted, which is preferable.

Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-). Propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexylphenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2 -Hydroxy-2-methyl-1-propane-1-one, 2-hirodoxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane- Aromatic ketone compounds such as 1-one; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2- Acetphenone compounds such as morpholinopropan-1; benzophenone compounds such as venzoin methyl ether, venzoin ethyl ether, benzoin isopropyl ether, venzoin butyl ether, anisoin methyl ether; benzyl dimethyl ketal, etc. Aromatic Ketal compounds; Aromatic sulfonyl chloride compounds such as 2-naphthalene sulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,1-propandion-2- (o-ethoxycarbonyl) oxime; Thioxanson, 2-Chlorothioxanthone, 2-methylthioxanson, 2,4-dimethylthioxanson, isopropylthioxanson, 2,4-dichlorothioxanson, 2,4-diethylthioxanson, 2,4-diisopropyl Thioxanson compounds such as thioxanson and dodecylthioxanthone; benzophenone; ketone halide; acylphosphinoxide; acylphosphonate and the like can be mentioned.

The blending amount of the photopolymerization initiator is 20% by weight or less when the total amount of the hard coat layer forming material is 100% by weight. The blending amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and further preferably 0.1 to 5% by weight.

[Manufacturing method of optical film]
The optical film (base film 1) can be produced by any method, but is preferably produced by a solution film forming method (casting method).

That is, in the optical film of the present embodiment, (1) a step of obtaining a dope containing a cycloolefin resin and a solvent, and (2) the obtained dope is cast on a metal support, dried and peeled to form a film. It can be produced through a step of obtaining a substance and (3) a step of drying the obtained film or stretching while drying.

Regarding the step (1), the solvent used for doping preferably contains an organic solvent (good solvent) capable of dissolving the cycloolefin resin. Examples of such good solvents include chlorine-based organic solvents such as methylene chloride (methylene chloride, dichloromethane); non-chlorine-based organic solvents such as methyl acetate, ethyl acetate, acetone and tetrahydrofuran. Of these, methylene chloride (methylene chloride) is preferable.

The solvent used for doping may further contain a poor solvent. Examples of poor solvents include straight-chain or branched-chain aliphatic alcohols having 1 to 4 carbon atoms. When the ratio of alcohol in the doping is high, the film-like substance tends to gel and peels off from the metal support easily. Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Of these, ethanol is preferably used because of its stability of doping, relatively low boiling point, and good drying property.

The doping obtained in the step (2) is cast on a metal support. Doping can be cast by discharging from a casting die.

The solvent in the dope cast on the metal support is then evaporated and dried. Then, the dried dope is peeled off from the metal support to obtain a film-like substance. The residual solvent amount of the doping when peeling from the metal support (residual solvent amount at the time of peeling) is 50 to 120% by mass in terms of facilitating reduction of the phase difference Ro and Rt of the obtained optical film. preferable. When the amount of residual solvent at the time of peeling is 50% by mass or more, the cycloolefin resin easily flows during drying or stretching and tends to be non-oriented, so that Ro and Rt of the obtained optical film can be easily reduced. When the amount of the residual solvent at the time of peeling is 120% by mass or less, the force required for peeling the dope is unlikely to be excessively large, so that the breakage of the dope is easily suppressed. The amount of residual solvent for doping is defined by the following formula.
Residual solvent amount of doping (mass%) = {(mass before heat treatment of doping)-(mass after heat treatment of doping)} / (mass after heat treatment of doping) × 100
The heat treatment for measuring the amount of residual solvent means a heat treatment at 120 ° C. for 60 minutes.

About the step (3) The obtained film-like substance is dried or stretched while being dried. Stretching can be done in at least one direction. The stretching direction may be any of the longitudinal direction of the film-like object (MD direction), the width direction orthogonal to the longitudinal direction of the film-like object (TD direction), and the oblique direction with respect to the longitudinal direction of the film-like object. Good.

The draw ratio is set according to the required optical performance. For example, from the viewpoint of making the optical film function as a λ / 4 film or a retardation film for VA (Vertical Alignment), it can be, for example, 1.31 to 5.0 times, which is the position for IPS (In Plane Switching). From the viewpoint of functioning as an retardation film, it can be, for example, 1.01 to 1.3 times. The stretch ratio is defined as (size of the film after stretching in the stretching direction) / (size of the film before stretching in the stretching direction).

The stretching temperature is preferably (Tg-30) ° C. to (Tg + 60) ° C., more preferably (Tg-10) ° C. to (Tg + 50) ° C., where Tg is the glass transition temperature of the cycloolefin resin. preferable. When the stretching temperature is (Tg-30) ° C. or higher, the tension applied to the film-like material during drying or stretching is unlikely to be excessively increased, so that Ro and Rt of the obtained optical film are unlikely to be excessively increased. When the stretching temperature is (Tg + 60) ° C. or lower, it is easy to highly suppress the generation of bubbles due to the vaporization of the solvent in the film-like material. Specifically, the stretching temperature can be 140 to 220 ° C.

The amount of residual solvent in the film-like material at the start of stretching is preferably 5 to 20% by mass. When the amount of residual solvent at the start of stretching is 5% by mass or more, the plasticizing effect of the residual solvent lowers the substantial Tg of the film-like substance at the time of stretching, so that Ro and Rt of the optical film are unlikely to increase. .. When the amount of residual solvent at the start of stretching is 20% by mass or less, the generation of bubbles due to the vaporization of the solvent in the film-like material can be highly suppressed. The amount of residual solvent in the film-like material at the start of stretching is more preferably 8 to 15% by mass.

Stretching of the film-like material in the MD direction can be performed, for example, by a method (roll method) in which a plurality of rolls are provided with a peripheral speed difference and the roll peripheral speed difference is used between them. Stretching of the film-like object in the TD direction can be performed, for example, by fixing both ends of the film-like object with clips or pins and widening the distance between the clips or pins in the traveling direction (tenter method).

〔Example〕
Specific examples of the present invention will be described below, but the present invention is not limited to these examples. A comparative example will also be described for comparison with the examples.

<< Example 1 >>
<Preparation of base film>
(Preparation of doping)
The following components were placed in a closed container, heated, and completely dissolved with stirring. This was filtered using Azumi Filter Paper No. 24 of Azumi Filter Paper Co., Ltd. to obtain a doping.
Cycloolefin resin (Arton G7810 (manufactured by JSR Corporation)) 95 parts by mass Dichloromethane 200 parts by mass Ethanol 10 parts by mass

(Film formation)
The obtained dope was kept at 30 ° C., and the dope was uniformly cast on a stainless steel belt which was a metal support kept at 30 ° C. Then, the cast dope was dried until the residual solvent amount became 30% by mass, and then peeled off from the stainless belt to obtain a film-like substance.

Then, the obtained film-like substance was dried at 40 ° C. until the residual solvent amount became 10% by mass, and then stretched in the width direction at a stretching ratio of 1.4 times (40%). Then, the obtained film-like material was further dried at 150 ° C. while being conveyed by a large number of rolls to obtain a base film F-1 having a length of 3000 m and a thickness of 20 μm.

<Preparation of easy-adhesion layer paint>
A thermosetting water-based polyolefin resin (Arrow Base SB1200 (trade name), solid content 25%, manufactured by Unitica Co., Ltd.) and an oxazoline-based cross-linking agent (WS-700, manufactured by Nippon Catalyst Co., Ltd.) are used as a diluent (diluting agent). After diluting with water / methanol = 30/70 (% by weight) until the solid content concentration became 5%, the mixture was stirred at room temperature to prepare the easy-adhesion layer coating material.

<Preparation of hard coat layer forming material>
Each material was mixed in the following ratios to prepare the hard coat layer forming material in Example 1.
・ Hard coat resin (urethane acrylate)
UA-306H (manufactured by Kyoeisha Chemical Co., Ltd.) 20 parts by mass ・ Photopolymerization initiator Irgacure 184 (manufactured by BASF Japan Co., Ltd.) 1.0 parts by mass ・ Additive KF-351A (manufactured by Shinetsu Chemical Co., Ltd.) 0.5 parts by mass -Diluting solvent Propylene glycol monomethyl ether (PGME) 32 parts by mass Methyl acetate (MA) 48 parts by mass (solvent mass ratio; MA / PGME = 60/40)

<Manufacturing of laminated film>
The easy-adhesive layer paint prepared above is applied to one side of a base film F-1 having a thickness of 20 μm with a bar coater, and dried in a drying furnace at 80 ° C. for 40 seconds to form a film. An easy-adhesion layer was formed so as to have a thickness of 0.4 μm. Then, at any time, the cross-linking rate on the surface of the easy-adhesive layer of the base film with the easy-adhesive layer was estimated by the calculation method described later.

Next, the hard coat layer forming material prepared above was applied on the prepared base film with an easy-adhesion layer with a bar coater, and dried in a drying oven at 50 ° C. for 40 seconds to volatilize the solvent. .. Then, in this state, while purging nitrogen so that the oxygen concentration becomes 1.0% by volume or less, the illuminance of the irradiation part is 100 mW / cm ² and the irradiation amount is 0.2 J / cm ² using an ultraviolet lamp. The coating layer was cured to prepare a laminated film (hard coat film) of Example 1. Then, the cross-linking rate of the easy-adhesion layer after the formation of the hard coat layer was estimated as follows. That is, the base film with an easy-adhesive layer produced in the same manner as above is dried by a dryer in a drying furnace at 50 ° C. for 40 seconds without forming a hard coat layer, and the cross-linking rate of the easy-adhesive layer is obtained by a calculation method described later. Was calculated, and the calculated cross-linking rate was used as the cross-linking rate of the easy-adhesive layer after the formation of the hard coat layer.

<< Examples 2 to 5 >>
Laminated films of Examples 2 to 5 were produced in the same manner as in Example 1 except that the drying temperature and / or film thickness of the easy-adhesion layer paint was changed as shown in Table 1.

<< Examples 6 to 8 >>
The thermosetting water-based polyolefin resin contained in the easy-adhesive layer paint is changed to Arrow Base SE1030N (trade name), solid content 25%, manufactured by Unitika Co., Ltd.), and the drying temperature of the easy-adhesive layer paint is changed as necessary. The laminated films of Examples 6 to 8 were produced in the same manner as in Example 1 except that the above was changed as shown in Table 1.

<< Comparative Example 1 >>
The laminated film of Comparative Example 1 was produced in the same manner as in Example 1 except that the cross-linking agent was not contained in the easy-adhesion layer paint and the drying temperature of the easy-adhesion layer paint was changed as shown in Table 1.

<< Comparative Examples 2-3 >>
Laminated films of Comparative Examples 2 and 3 were produced in the same manner as in Example 1 except that the drying temperature of the easy-adhesion layer paint was changed as shown in Table 1.

<< Comparative Example 4 >>
The resin contained in the easy-adhesion layer paint was changed to a solvent-based olefin resin (Surflen (registered trademark) P-1000, manufactured by Mitsubishi Chemical Co., Ltd.), and the drying temperature of the easy-adhesion layer paint was changed as shown in Table 1. A laminated film of Comparative Example 4 was produced in the same manner as in Example 1 except for the above.

≪Calculation method of cross-linking rate≫
The cross-linking rate on the surface of the easy-adhesion layer was measured by the ATR method (Attenuated Total Reflection). More specifically, using an FT-IR Magna 860-NIC plan IR-Microscope manufactured by Nicoley Co., Ltd., in the obtained FT-IR spectrum, the peak of 1720 cm ^-1 of the carboxylic acid moiety before cross-linking was added with a cross-linking agent. The rate of decrease with respect to the peak height of 1720 cm ^-1 in the non-infrared system was calculated, and the calculated value was used as the cross-linking rate. That is, the cross-linking rate is expressed by the following formula.
Crosslink rate (%) = (AB) / A × 100
here,
A: peak height of 1720 cm ^-1 in the state without the crosslinking agent added B: is the peak height of 1720 cm ^-1 in a state in which the crosslinking agent was added thereto.

≪Measuring method of film thickness of easy adhesive layer≫
The film thickness of the easy-adhesion layer was measured as follows. That is, a black acrylic plate is bonded to the surface of the base film opposite to the easy-adhesion layer with a base material-less tape (manufactured by Lintec), and the reflectance of each wavelength on the outermost surface side of the base film is spectrophotometrically manufactured by Konica Minolta. It was measured with a colorimeter CM-3700d. On the other hand, the refractive indexes of the easy-adhesion layer and the base film are measured by an Abbe refractive index meter, and for example, the reflectance estimated from the refractive index by Frenel's formula and the reflection measured by the above spectrocolorimeter. The actual film thickness was calculated from the spectrum (refractive index).

≪Evaluation≫
<Initial adhesion>
Each laminated film is made in an atmosphere of 23 ° C. and 55% RH by a method conforming to JIS K 5400, and 11 cuts are made in the hard coat layer of each laminated film at 1 mm intervals in the vertical and horizontal directions, and 100 pieces of 1 mm square. The grid was made, and cellophane tape was attached and quickly peeled off at a 90 degree angle. The cellophane tape was replaced every time it was peeled off, and after the tape was peeled off 10 times, the initial adhesion was evaluated based on the area of the grid remaining without peeling off according to the following five criteria. ..
"Evaluation criteria"
5: No peeling (there are no peeled grids).
4: The number of stripped grids is 1-2.
3: There are 3 to 5 grids that have been peeled off.
2: The number of peeled grids is 6 to 15.
1: The number of peeled grids is 16 or more (poor adhesion).

<Hou-proof adhesion>
A weather resistance test was conducted on each laminated film, and the weather resistance was evaluated using the same evaluation criteria as the above initial adhesion. At this time, the weather resistance test uses a Xe weather resistance test device (Suga Test Instruments Co., Ltd., xenon weather meter NX25) to irradiate each laminated film with light (ultraviolet rays) having a wavelength of 300 to 400 nm for 300 hours at an irradiation intensity of 60 W. Got by doing.

<Initial curl>
Each laminated film was cut into a size of 10 cm in length × 10 cm in width, the lift of the edge portion of each cut out sample piece was measured, and the initial curl was evaluated according to the following five-step criteria.
"Evaluation criteria"
5: The lift of the edge portion of the sample piece is less than 5 mm.
4: The lift of the edge portion of the sample piece is 5 mm or more and less than 1 cm.
3: The lift of the edge portion of the sample piece is 1 cm or more and less than 2 cm.
2: The lift of the edge portion of the sample piece is 2 cm or more and less than 5 cm.
1: The sample piece becomes tubular (the curl is large and it is defective).

<Curl after weather resistance>
A weather resistance test was performed on each laminated film, and the post-housing curl was evaluated according to the same evaluation criteria as the above initial curl. The weather resistance test at this time was performed under the same conditions as in the evaluation of the weather resistance.

Table 1 shows various conditions of Examples 1 to 8 and Comparative Examples 1 to 4 and the evaluation results.

From Table 1, the initial adhesion is good in both Examples 1 to 8 and Comparative Examples 1 to 4, but the weather adhesion is poor in Comparative Examples 1, 3 and 4. In Comparative Example 1, since the easy-adhesion layer does not contain a cross-linking agent, even if ultraviolet rays are irradiated over time, the cross-linking reaction of the cross-linking agent cannot be used to ensure the adhesion, and the adhesion is improved. It is considered to be decreasing. Further, in Comparative Example 3, the cross-linking rate of the easy-adhesive layer after coating the hard coat layer was as high as 91%, and the unreacted portion of the cross-linking agent was too small. Therefore, even if ultraviolet rays were subsequently irradiated over time, the cross-linking reaction occurred. It is considered that the adhesive cannot be fully utilized, and as a result, the adhesiveness is deteriorated. Further, in Comparative Example 4, since the olefin resin contained in the easy-adhesion layer is solvent-based and easily dissolves the base film, stable adhesion between the easy-adhesion layer and the base film can be ensured. As a result, it is considered that the adhesion between the base film and the hard coat layer over time is reduced. In Comparative Example 4, cracks and poor appearance of the base film were observed, which is considered to be due to the solvent-based olefin resin in the easy-adhesion layer dissolving the base film.

Further, in Comparative Examples 2 and 3, the evaluation of the initial curl and the curl after weather resistance is poor. In Comparative Example 2, since the cross-linking rate of the easy-adhesive layer 2 is as low as 20% and there are many unreacted portions of the cross-linking agent, drying during formation of the hard coat layer, heating during UV irradiation, and UV irradiation in the weather resistance test It is considered that the easy-adhesion layer 2 is easily cured and shrunk by the heating of the above, and as a result, the laminated film is curled.

On the other hand, in Examples 1 to 8, the weather resistance is good and the curl after the weather resistance is also good (there is little curl). Since the easy-adhesive layer contains a cross-linking agent and the cross-linking rate is in an appropriate range of 23% or more and 85% or less, even if ultraviolet rays are irradiated over time after forming the hard coat, the easy-adhesive layer is cured and shrunk. It is considered that the cross-linking reaction of the cross-linking agent can be fully utilized while suppressing the curling, and thus the adhesion can be improved while suppressing the curl over time. The cross-linking rate of 23% is considered as a critical point existing between 20% of Comparative Example 2 and 26% of Examples 3 and 8. Similarly, the crosslink rate of 85% is considered as a critical point existing between 91% of Comparative Example 3 and 78% of Examples 1 and 6.

In particular, as in Examples 1 to 8, when the cross-linking rate of the easy-adhesion layer is within the range of 26% or more and 78% or less, it is possible to surely obtain the effect of satisfying both the weather adhesion resistance and the curl after the weather resistance. It can be said that it can be done. Further, in Examples 2, 4, 5 and 7, since the weather adhesion is the best, if the cross-linking rate of the easy-adhesion layer is 35% or more and 46% or less, the effect of improving the adhesion over time can be obtained. It can be said that it can be further enhanced.

Further, in Examples 1 to 8, when the cross-linking rate of the easy-adhesion layer is 10 to 80%, the hard coat layer forming material is applied on the easy-adhesion layer. Thereby, the cross-linking reaction of the cross-linking agent can be further advanced by the subsequent drying and heating at the time of ultraviolet irradiation, and the above-mentioned cross-linking rate of 23 to 85% of the easy-adhesive layer can be realized.

<< Examples 9 to 10 >>
Implemented except that the cross-linking agent included in the easy-adhesion layer paint was changed to a carbodiimide-based cross-linking agent (V-02-L2, manufactured by Nisshinbo Chemical Co., Ltd.) and an aziridine-based cross-linking agent (PZ-33, manufactured by Nippon Shokubai Co., Ltd.). The laminated films of Examples 9 to 10 were produced in the same manner as in Example 1.

Table 2 shows various conditions of Examples 1 and 9 to 10 and the evaluation results.

From Table 2, it can be seen that Examples 1 and 9 have better weather adhesion than Example 10. The carbodiimide-based cross-linking agent of Example 9 or the oxazoline-based cross-linking agent of Example 1 forms an amide ester structure after cross-linking. When the weather resistance test was performed, it is considered that the weather resistance was further improved because the chemical interaction between the above-mentioned amide ester structure and the polar group of the hard coat layer occurred.

<< Examples 11 to 17 >>
Laminated films of Examples 11 to 17 were produced in the same manner as in Example 1 except that the type and mass ratio of the solvent contained in the hard coat layer forming material were changed as shown in Table 3.

Table 3 shows various conditions of Examples 1 and 11 to 17 and the evaluation results.

From Table 3, in Examples 1, 11 to 13 and 15 to 16, the weather adhesion is further improved as compared with the initial adhesion. When the mass ratio of alcohols or glucol ethers to the total solvent is 20% or more as in these examples, excessive penetration of the solvent from the hard coat layer forming material into the polyolefin-based easy-adhesion layer is suppressed. To. As a result, a more uniform permeation state can be formed, and it is considered that not only the initial adhesion but also the adhesion between the easy-adhesion layer and the hard coat layer can be improved after the weather resistance test. By the way, when the solvent excessively permeates into the easy-adhesion layer, stress concentrates on the part that has permeated too much (hard coat concentration is high = hard), and it becomes easy to peel off as a result. It is considered that not only the initial adhesion but also the weather adhesion is improved because the peeling stress is uniformly applied because the permeation state is not uneven.

<< Examples 18 to 20 >>
The hard coat resin to be included in the hard coat layer forming material is pentaerythritol acrylate (NK ester A-TMM-3L, manufactured by Shin Nakamura Chemical Industry Co., Ltd.) and urethane acrylate (NK oligo UA-1100H, manufactured by Shin Nakamura Chemical Industry Co., Ltd.). , Aronix M-400 (dipentaerythritol penta and hexaacrylate, manufactured by Toa Synthetic Co., Ltd.) were used, and laminated films of Examples 18 to 20 were prepared in the same manner as in Example 1.

Table 4 shows various conditions of Examples 1 and 18 to 20 and the evaluation results.

From Table 4, in Examples 1 and 19 in which the hard coat resin is urethane acrylate, the weather adhesion is improved as compared with Examples 18 and 20 in which the hard coat resin is another resin. This is because the chemical interaction between the urethane bonding portion of the urethane acrylate and the cross-linking agent of the easy-adhesion layer acts during the weather resistance test, so that the adhesion between the easy-adhesion layer and the hard coat layer is improved. it is conceivable that.

[Supplement]
From the above, the laminated film described in this embodiment and the method for producing the same can be expressed as follows.

1. 1. A base film containing a cycloolefin resin and
An easy-adhesive layer containing thermosetting water-based polyolefin and a cross-linking agent,
A hard coat layer containing an ionizing radiation curable resin is provided in this stacking order.
A laminated film characterized in that the cross-linking rate of the easy-adhesion layer is 23 to 85%.

2. 2. The laminated film according to 1 above, wherein the cross-linking rate of the easy-adhesion layer is 26 to 78%.

3. 3. The laminated film according to 1 or 2, wherein the cross-linking rate of the easy-adhesion layer is 35 to 46%.

4. The laminated film according to any one of 1 to 3 above, wherein the cross-linking agent is a carbodiimide-based film or an oxazoline-based film.

5. The laminated film according to any one of 1 to 4, wherein the hard coat layer contains urethane acrylate as the ionizing radiation curable resin.

6. The method for producing a laminated film according to any one of 1 to 5 above.
An easy-adhesion layer forming step of forming the easy-adhesion layer on the base film,
A hard coat layer forming step of forming the hard coat layer on the easy-adhesion layer is included.
In the hard coat layer forming step, when the cross-linking rate of the easy-adhesive layer is 10 to 80%, a hard coat layer-forming material containing the ionizing radiation curable resin is applied onto the easy-adhesive layer, and then A laminated film characterized in that the hard coat layer is formed by curing the ionizing radiation curable resin by drying and irradiation with ionizing radiation, and the cross-linking rate of the easy-adhesive layer is adjusted to 23 to 85%. Manufacturing method.

7. The hard coat layer forming material contains a solvent and contains a solvent.
The solvent contains alcohols or glycol ethers and contains
The method for producing a laminated film according to 6, wherein the mass ratio of the alcohols or the glucol ethers to the whole solvent is 20% or more.

It is desirable that the solvent contained in the hard coat forming material described in the present embodiment has a low attack property that does not easily dissolve the olefin resin in the easy-adhesion layer. This is because when the solvent dissolves the olefin resin in the easy-adhesion layer, a porous structure is formed in the easy-adhesion layer or cracks are formed, and the hard coat layer is easily peeled off at that portion.

As the solvent to be included in the easy-adhesion layer, a desired material that can be applied within a range that does not cause cracks in the base film may be selected and used. For example, as the solvent, materials such as water, alcohol, and ether may be used in any combination.

The laminated film of the present invention can be used as a protective film for a polarizing plate used in, for example, a liquid crystal display device or an organic EL display device.

1 Base film 2 Easy-adhesion layer 3 Hard coat layer 10 Laminated film

Claims (7)

A base film containing a cycloolefin resin and
An easy-adhesive layer containing thermosetting water-based polyolefin and a cross-linking agent,
A hard coat layer containing an ionizing radiation curable resin is provided in this stacking order.
A laminated film characterized in that the cross-linking rate of the easy-adhesion layer is 23 to 85%. The laminated film according to claim 1, wherein the cross-linking rate of the easy-adhesion layer is 26 to 78%. The laminated film according to claim 1 or 2, wherein the cross-linking rate of the easy-adhesion layer is 35 to 46%. The laminated film according to any one of claims 1 to 3, wherein the cross-linking agent is a carbodiimide-based or an oxazoline-based. The laminated film according to any one of claims 1 to 4, wherein the hard coat layer contains urethane acrylate as the ionizing radiation curable resin. The method for producing a laminated film according to any one of claims 1 to 5.
An easy-adhesion layer forming step of forming the easy-adhesion layer on the base film,
A hard coat layer forming step of forming the hard coat layer on the easy-adhesion layer is included.
In the hard coat layer forming step, when the cross-linking rate of the easy-adhesive layer is 10 to 80%, a hard coat layer-forming material containing the ionizing radiation curable resin is applied onto the easy-adhesive layer, and then A laminated film characterized in that the hard coat layer is formed by curing the ionizing radiation curable resin by drying and irradiation with ionizing radiation, and the cross-linking rate of the easy-adhesive layer is adjusted to 23 to 85%. Manufacturing method. The hard coat layer forming material contains a solvent and contains a solvent.
The solvent contains alcohols or glycol ethers and contains
The method for producing a laminated film according to claim 6, wherein the mass ratio of the alcohols or the glucol ethers to the whole solvent is 20% or more.

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