TWI628078B - Laminated body and method for manufacturing laminated body - Google Patents

Abstract

The present invention provides a laminate having both good adhesion and good appearance. The laminate of the present invention has a resin base material and a polyvinyl alcohol-based resin layer formed on one side of the resin base material. The resin base material side of the polyvinyl alcohol-based resin layer is regarded as an intermediate region where a polyolefin-based component exists.

Description

Laminated body and method for manufacturing laminated body

Field of the Invention The present invention relates to a laminate having a polyvinyl alcohol-based resin layer.

BACKGROUND OF THE INVENTION There is a document that proposes a method for forming a polarizing film by forming a polyvinyl alcohol-based resin layer on a resin substrate and extending and dyeing the laminate (for example, Patent Document 1). By this method, a thin polarizing film can be obtained, so it can contribute to the thinning of the image display device, for example, and attracts attention.

The polarizing film can be directly used in a state of being laminated on the resin substrate. In this embodiment, the polyvinyl alcohol-based resin layer (polarizing film) and the resin substrate must have sufficient adhesion. Specifically, for example, when manufacturing a polarizing film (for example, during stretching and transportation), the polyvinyl alcohol-based resin layer is not peeled from the resin substrate, the polarizing film is not peeled from the resin substrate during heavy work, or is processed (such as punching) or During use, no polarizing film or resin substrate floats due to impact.

In order to improve the above-mentioned adhesiveness, there is a literature proposal to provide a primer layer containing a polyvinyl alcohol-based material between the resin substrate and the polyvinyl alcohol-based resin layer (Patent Document 2). However, when the primer layer is provided, there is a problem that it is difficult to obtain a good appearance. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2000-338329 Patent Document 2: Japanese Patent No. 4950357

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The present invention is implemented to solve the above problems, and its main purpose is to provide a laminate having both good adhesion and good appearance. Means to solve the problem

According to the present invention, a laminate can be provided. The laminate of the present invention has a resin base material and a polyvinyl alcohol-based resin layer formed on one side of the resin base material. The resin base material side of the polyvinyl alcohol-based resin layer is regarded as an intermediate region where a polyolefin-based component exists. In one embodiment, the intermediate region contains a polyvinyl alcohol-based component and a polyolefin-based component. In one embodiment, the polyvinyl alcohol-based component includes acetoxyethyl modified polyvinyl alcohol. In one embodiment, the blending ratio of the polyvinyl alcohol-based component and the polyolefin-based component is 5: 95-60: 40. In one embodiment, the thickness of the middle region is 100 nm to 1000 nm. According to another aspect of the present invention, a method for manufacturing a laminate can be provided. The manufacturing method of the laminate includes the steps of: applying a composition for forming an undercoat layer containing a polyolefin-based component to one side of a resin substrate to form an undercoat layer; A coating solution of an alcohol-based resin forms a coating layer of a polyvinyl alcohol-based resin. In one embodiment, the undercoat layer-forming composition contains a polyvinyl alcohol-based component and a polyolefin-based component. In one embodiment, the polyvinyl alcohol-based component includes acetoxyethyl modified polyvinyl alcohol. In one embodiment, the blending ratio of the solid component of the polyvinyl alcohol component and the polyolefin component is 5: 95-60: 40. In one embodiment, the thickness of the above primer layer is 500 nm to 3000 nm. According to another aspect of the present invention, a method for manufacturing a polarizing plate can be provided. The manufacturing method of the polarizing plate includes the steps of stretching and dyeing the laminate produced by the above manufacturing method. According to another aspect of the present invention, a polarizing plate can be provided. The polarizing plate has a resin base material and a polyvinyl alcohol-based resin layer formed on one side of the resin base material. The resin base material side of the polyvinyl alcohol-based resin layer is regarded as an intermediate region where a polyolefin-based component exists, and the polyvinyl alcohol-based resin layer is an oriented polarizing film that adsorbs a dichroic substance. In one embodiment, the intermediate region contains a polyvinyl alcohol-based component and a polyolefin-based component. In one embodiment, the polyvinyl alcohol-based component includes acetoxyethyl modified polyvinyl alcohol. In one embodiment, the blending ratio of the polyvinyl alcohol-based component and the polyolefin-based component is 5: 95-60: 40. In one embodiment, the thickness of the middle region is 100 nm to 1000 nm. Effect of invention

According to the present invention, by making the resin base material side of the polyvinyl alcohol-based resin layer an intermediate region where a polyolefin-based component exists, a laminate having good adhesion and good appearance can be obtained.

Forms for Carrying Out the Invention Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

A. Laminate The laminate of the present invention has a resin base material and a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") layer formed on one side of the resin base material, and at least the resin base material side of the PVA-based resin layer It is considered that there is an intermediate region of the polyolefin-based component. In one embodiment, the intermediate region substantially corresponds to an undercoat layer described below, and the PVA-based resin layer contains an undercoat layer and a PVA-based resin coating layer described below. In another embodiment, the PVA-based resin layer substantially constitutes a single layer, and the intermediate region is regarded as a compatible region of the PVA-based resin coating layer and the undercoat layer. In addition, the PVA-based resin layer is made into a polarizing film through various treatments, and the laminate can also be regarded as a polarizing plate.

A-1. Resin base material The above-mentioned resin base material may use any appropriate material. Examples thereof include ester resins such as polyethylene terephthalate resins, olefin resins such as cycloolefin resins and polypropylene, (meth) acrylic resins, polyamide resins, and polycarbonate resins. And such copolymer resins. Polyethylene terephthalate resin is suitable. Among them, amorphous polyethylene terephthalate resin is suitable. Specific examples of the amorphous polyethylene terephthalate-based resin include copolymers further containing isophthalic acid as dicarboxylic acid or copolymers further containing cyclohexane dimethanol as glycol.

The glass transition temperature (Tg) of the resin substrate is preferably 170 ° C or lower. By using such a resin base material, it is possible to suppress the crystallization of the PVA-based resin layer while sufficiently ensuring the extensibility. From the viewpoint of plasticizing the resin base material with water and smoothly extending in water, it is more preferably 120 ° C or lower. In one embodiment, the glass transition temperature of the resin substrate is preferably 60 ° C or higher. By using such a resin base material, it is possible to prevent defects such as deformation of the resin base material (such as unevenness, sag, wrinkles, etc.) when applying and drying a coating solution containing a PVA-based resin described later. In addition, the laminate can be extended at an appropriate temperature (for example, about 60 ° C to 70 ° C). In another embodiment, the coating liquid containing the PVA-based resin may be lower than 60 ° C. as long as the resin base material is not deformed during application and drying. In addition, the glass transition temperature (Tg) is a value determined in accordance with JIS K 7121.

In one embodiment, the water absorption rate of the resin substrate is preferably 0.2% or more, and more preferably 0.3% or more. This type of resin substrate absorbs water, and water can play the role of plasticizer for plasticization. As a result, the elongation stress can be greatly reduced during the elongation in water while having excellent elongation. On the other hand, the water absorption rate of the resin substrate is preferably 3.0% or less, and more preferably 1.0% or less. By using such a resin base material, it is possible to prevent such a problem that the dimensional stability of the resin base material is significantly reduced during manufacturing and the appearance of the resulting laminate is deteriorated. In addition, it can prevent breakage or peeling of the PVA-based resin film from the resin base material when extending in water. In addition, the water absorption rate is a value determined according to JIS K 7209.

The thickness of the resin substrate is preferably 20 μm to 300 μm, more preferably 30 μm to 200 μm.

On the surface of the resin substrate, a surface modification treatment (such as corona treatment, etc.) or an easy adhesion layer may be formed in advance. Through these treatments, the adhesion can be further enhanced.

A-2. PVA-based resin layer The PVA-based resin that forms the PVA-based resin layer may be any appropriate resin. Examples include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying the ethylene-vinyl acetate copolymer. The saponification degree of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be obtained according to JIS K 6726-1994. By using such a PVA resin with a degree of saponification, a polarizing film with excellent durability can be obtained. When the degree of saponification is too high, there is a risk of gelatinization.

The average degree of polymerization of the PVA-based resin can be appropriately selected according to the purpose. The average polymerization degree is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. In addition, the average degree of polymerization can be determined in accordance with JIS K 6726-1994.

The thickness of the PVA-based resin layer is typically 20 μm or less, preferably 15 μm or less. When the PVA-based resin layer is used as the polarizing film, its thickness is preferably 10 μm or less, more preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm or less. On the other hand, the thickness of the PVA-based resin layer is preferably 1.0 μm or more, and more preferably 2.0 μm or more.

When the PVA-based resin layer is used as the polarizing film, the PVA-based resin layer is substantially in a state in which the dichroic substance is adsorbed and oriented, and it is preferable to exhibit absorption dichroism at any wavelength of the wavelength of 380 nm to 780 nm. At this time, the monomer transmittance of the PVA-based resin layer is preferably 40.0% or more, more preferably 41.0% or more, more preferably 42.0% or more, and particularly preferably 43.0% or more. The polarization degree of the PVA-based resin layer is preferably 99.8% or more, more preferably 99.9% or more, and even more preferably 99.95% or more.

As described above, the resin base material side of the PVA-based resin layer is regarded as the intermediate region where the polyolefin-based component exists. By forming such areas, good adhesion and good appearance can be achieved. The thickness of the middle region is, for example, 100 nm to 1000 nm. The intermediate region can be confirmed by observing the cross-section of the laminate with a scanning electron microscope (SEM), for example. The presence or absence of polyolefin-based components can be confirmed by, for example, time-of-flight secondary ion mass spectrometry (TOF-SIMS) or infrared spectroscopy (IR). In one embodiment, the middle region contains a polyvinyl alcohol-based component and a polyolefin-based component. In addition, the details of the polyolefin-based component and the polyvinyl alcohol-based component will be described in detail later.

B. Manufacturing method As long as the layered body of the present invention can obtain the above-mentioned configuration, it can be manufactured by any suitable method. In one embodiment, it is manufactured by a method including the steps of: applying a composition for forming an undercoat layer containing a polyolefin-based component on one side of a resin substrate to form an undercoat layer; and coating the surface of the undercoat layer A coating solution containing a PVA-based resin is distributed to form a PVA-based resin coating layer.

B-1. Formation of undercoat layer The composition for forming an undercoat layer preferably contains a polyvinyl alcohol-based component and a polyolefin-based component. By setting it as such a composition, the laminated body which has both good adhesiveness and good appearance can be obtained. As the polyvinyl alcohol-based component, any and appropriate PVA-based resin can be used. Specific examples include polyvinyl alcohol and modified polyvinyl alcohol. Examples of the modified polyvinyl alcohol include polyvinyl alcohol modified with an acetyl acetyl group, a carboxylic acid group, an acrylic acetyl group, and / or an urethane group. In these, it is advisable to use acetyl acetyl modified PVA. It is preferable to use a polymer having at least a repeating unit represented by the following general formula (I) for the modified PVA of acetyl acetyl group.

[Chem 1]

In the above formula (I), the ratio of n to l + m + n is preferably 1% to 10%.

The average polymerization degree of acetylated acetyl modified PVA is preferably 1000 ~ 10000, more preferably 1200 ~ 5000. The saponification degree of acetylated acetyl modified PVA should be more than 97 mole%. The pH value of the 4% by weight aqueous solution of acetylated acetyl modified PVA is preferably 3.5 to 5.5. In addition, the average degree of polymerization and the degree of saponification can be calculated according to JIS K 6726-1994.

As the polyolefin-based component, any and appropriate polyolefin-based resin can be used. Examples of the olefin component of the main component of the polyolefin-based resin include olefinic hydrocarbons having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, and 1-hexene. These can be used alone or in combination of two or more. Among them, olefinic hydrocarbons having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are preferred. Ethylene is more preferred.

Among the monomer components constituting the above polyolefin resin, the proportion of the olefin component is preferably 50% by weight to 95% by weight.

The polyolefin resin preferably has a carboxyl group and / or its anhydride group. This type of polyolefin resin can be dispersed in water and can form an excellent primer layer. Examples of monomer components having such functional groups include unsaturated carboxylic acids and their anhydrides, half esters of unsaturated dicarboxylic acids, and hemiamides. Such specific examples include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, and crotonic acid.

The molecular weight of the polyolefin resin is, for example, 5,000 to 80,000.

In the composition for forming an undercoat layer, the blending ratio (solid content) of the polyvinyl alcohol-based component and the polyolefin-based component is preferably 5:95 to 60:40, and more preferably 20:80 to 50:50. If there are too many polyvinyl alcohol-based components, it may not be possible to obtain sufficient adhesion. Specifically, when the PVA-based resin layer is peeled from the resin base material, the required peeling force may be reduced and sufficient adhesion cannot be obtained. On the other hand, if the polyvinyl alcohol-based component is too small, the appearance of the resulting laminate may be damaged. Specifically, when forming an undercoat layer to be described later, inconveniences such as white turbidity of the coating film may occur, making it difficult to obtain a laminate having an excellent appearance.

The composition for forming the undercoat layer is preferably an aqueous system. The composition for forming an undercoat layer may contain an organic solvent. Examples of organic solvents include ethanol and isopropanol. The solid content concentration of the composition for forming an undercoat layer is preferably 1.0% by weight to 10% by weight.

Additives may also be incorporated into the composition for forming the undercoat layer. Examples of additives include crosslinking agents. Examples of crosslinking agents are: Hydroxymethyl compounds such as oxazoline, boric acid, trimethylolmelamine, carbodiimide, isocyanate compounds, epoxy compounds, etc. The blending amount of the additive for the undercoat layer forming composition can be appropriately set according to the purpose and the like. For example, with respect to a total of 100 parts by weight of the polyvinyl alcohol-based component and the polyolefin-based component, the blending amount of the crosslinking agent is preferably 10 parts by weight or less, more preferably 0.01 parts by weight to 10 parts by weight, more preferably 0.1 parts by weight ~ 5 parts by weight.

The method for applying the composition for forming the undercoat layer can be any appropriate method. Examples include: roll coating method, spin coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, spray coating method, doctor blade coating method (angular wheel coating method, etc.), etc. .

The composition for forming an undercoat layer is preferably applied in such a manner that the thickness of the obtained undercoat layer is 500 nm to 3000 nm, and more preferably 800 nm to 2000 nm. If the thickness of the undercoat layer is too thin, sufficient adhesion may not be obtained. In addition, if the thickness of the undercoat layer is too thick, cissing may occur during the formation of the PVA-based resin coating layer described later and unevenness may occur in the resulting coating film, and it is difficult to produce a good-looking appearance Layered body.

After applying the composition for forming an undercoat layer, the coating film may be dried. The drying temperature is, for example, 50 ° C or higher.

B-2. Formation of PVA-based resin coating layer The surface of the undercoat layer coated with the coating solution containing the PVA-based resin may be subjected to surface modification treatment (such as corona treatment, etc.) in advance. Through these treatments, the adhesion can be further enhanced.

The above-mentioned PVA-based resin-containing coating liquid represents a solution in which the above-mentioned PVA-based resin has been dissolved in a solvent. Examples of solvents include: water, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, trimethylolpropane and other polyols, ethylenedioxide Amine, diethylenetriamine and other amines. These can be used alone or in combination of two or more. Among these, water is better. The concentration of the PVA resin in the coating liquid is preferably 3-20 parts by weight relative to 100 parts by weight of the solvent. As long as it is such a resin concentration, a uniform coating film can be formed.

Additives can be blended in the coating liquid. Examples of additives include plasticizers and surfactants. Plasticizers include polyhydric alcohols such as ethylene glycol and glycerin. The surfactant can be exemplified by nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability, and extensibility of the resulting PVA-based resin layer. In addition, additives can be mentioned as easily accessible ingredients. By using easily accessible components, the adhesion can be further improved. For easily accessible components, for example, modified PVA such as acetyl-acetyl-modified PVA can be used.

The coating method of the coating liquid can be the same as the coating method of the above-mentioned undercoat layer forming composition. After coating, the coating film can be dried. The drying temperature is, for example, 50 ° C or higher.

B-3. Production of polarizing film As mentioned above, the laminate can be subjected to various treatments. Specific examples of various treatments include dyeing treatment, extension treatment, insolubilization treatment, cross-linking treatment, washing treatment, and drying treatment. These treatments can be appropriately selected according to the purpose. In addition, the processing order, processing timing, processing times, etc. can be appropriately set. The following points explain each process.

(Dyeing treatment) The above-described dyeing treatment is performed by dyeing the PVA-based resin layer with a dichroic substance. Preferably, the dichroic substance is adsorbed on the PVA-based resin layer. Examples of the adsorption method include a method of immersing a PVA-based resin layer (laminate) in a dye solution containing a dichroic substance, a method of applying the dye solution on a PVA-based resin layer, and the dye solution The method of spraying onto the PVA-based resin layer, etc. It is desirable to immerse the PVA-based resin layer in the dyeing solution. Because it can absorb dichroic substances well.

Examples of the dichroic substance include iodine and organic dyes. These can be used alone or in combination of two or more. The dichroic substance is preferably iodine. When iodine is used as the dichroic substance, the dyeing solution is preferably an aqueous iodine solution. The blending amount of iodine is preferably 0.1 to 0.5 parts by weight relative to 100 parts by weight of water. In order to improve the solubility of iodine in water, it is appropriate to blend iodide in the iodine aqueous solution. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Among these, potassium iodide is suitable. The blending amount of iodide is preferably 0.02 to 20 parts by weight, more preferably 0.1 to 10 parts by weight relative to 100 parts by weight of water.

In order to suppress the dissolution of the PVA-based resin, the temperature of the dyeing liquid during dyeing is preferably 20 ° C to 50 ° C. When immersing the PVA-based resin layer in the dyeing solution, in order to ensure the transmittance of the PVA-based resin layer, the immersion time is preferably 5 seconds to 5 minutes. In addition, the dyeing conditions (concentration, liquid temperature, immersion time) can be set so that the polarization degree or cell transmittance of the polarizing film finally obtained is within a predetermined range. In one embodiment, the immersion time is set so that the polarization degree of the obtained polarizing film is 99.98% or more. In another embodiment, the immersion time is set such that the unit transmittance of the obtained polarizing film is 40% to 44%.

(Extending treatment) Any and appropriate method can be adopted for the extending method of the laminate. Specifically, it may be a fixed-end extension (for example, a method using a tenter stretcher) or a free-end extension (for example, a method for uniaxially extending a laminate through rollers with different turnover rates). Furthermore, it may be a synchronous biaxial extension (for example, a method using a synchronous biaxial extension machine) or a stepwise biaxial extension. The extension of the laminate can be performed in one stage or in multiple stages. When performing in multiple stages, the stretching magnification (maximum stretching magnification) of the laminate to be described later is the product of the stretching magnification in each stage.

The stretching treatment may be a water stretching method in which the laminate is immersed in an stretching bath, or an air stretching method. In one embodiment, the underwater extension treatment is performed at least once, so it is preferable to combine the underwater extension treatment and the aerial extension treatment. By extending in water, it can be extended at a temperature lower than the glass transition temperature of the above resin substrate or PVA-based resin layer (typically around 80 ° C), which can suppress the crystallization of the PVA-based resin layer and increase the temperature Magnification extension. Thus, a polarizing film having excellent polarization characteristics can be manufactured.

The extending direction of the laminate can be any arbitrary and appropriate direction. In one embodiment, it extends along the longitudinal direction of the elongated laminate. Specifically, the laminate is transported in the longitudinal direction, which is the transport direction (MD). In another embodiment, it extends along the width direction of the elongated laminate. Specifically, the laminate is transported in the longitudinal direction, that is, the direction (TD) orthogonal to the transport direction (MD).

The stretching temperature of the laminate can be set to an arbitrary and appropriate value according to the forming material of the resin base material, the stretching method, and the like. When using the air stretching method, the stretching temperature is preferably higher than the glass transition temperature (Tg) of the resin substrate, more preferably the glass transition temperature (Tg) of the resin substrate + 10 ° C or higher, and particularly preferably Tg + 15 ° C or higher. On the other hand, the elongation temperature of the laminate is preferably 170 ° C or lower. Elongation at these temperatures can suppress the rapid progress of crystallization of the PVA-based resin, and can further suppress the defects caused by the crystallization (for example, the orientation of the PVA-based resin layer is hindered by the extension).

When the extension method in water is used as the extension method, the temperature of the liquid in the extension bath is preferably 40 ° C to 85 ° C, more preferably 50 ° C to 85 ° C. As long as it is within these temperatures, the PVA-based resin layer can be inhibited from dissolving, and at the same time can be stretched at a high rate. Specifically, as described above, the glass transition temperature (Tg) of the resin substrate is preferably 60 ° C. or higher in relation to the formation of the PVA-based resin layer. At this time, if the elongation temperature is lower than 40 ° C, even if the resin base material is considered to be plasticized with water, it may not be able to elongate well. On the other hand, the higher the temperature of the stretching bath, the higher the solubility of the PVA-based resin layer, and it may be impossible to obtain excellent polarization characteristics.

When the underwater stretching method is adopted, it is preferable to immerse the laminate in a boric acid aqueous solution for stretching (boric acid underwater stretching). By using a boric acid aqueous solution as an extension bath, the PVA-based resin layer can be given rigidity that can withstand the tension applied during extension and water resistance that is insoluble in water. Specifically, boric acid can generate tetrahydroxyborate anions in aqueous solution, and cross-link with PVA-based resin through hydrogen bonding. As a result, the PVA-based resin layer can be imparted with rigidity and water resistance, and further can be well stretched to produce a polarizing film having excellent polarizing characteristics.

The aforementioned aqueous solution of boric acid is preferably obtained by dissolving boric acid and / or borate in water of a solvent. The concentration of boric acid is preferably 1 part by weight to 10 parts by weight relative to 100 parts by weight of water. By setting the concentration of boric acid to 1 part by weight or more, the dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizing film with higher characteristics can be produced. In addition to boric acid or borate, an aqueous solution obtained by dissolving boron compounds such as borax, glyoxal, glutaraldehyde and the like in a solvent can also be used.

It is suitable to blend iodide in the above extension bath (boric acid aqueous solution). By blending iodide, the elution of iodine that has been adsorbed to the PVA-based resin layer can be suppressed. Specific examples of iodide are the same as described above. Relative to 100 parts by weight of water, the concentration of iodide is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 8 parts by weight.

The immersion time of the laminate in the extension bath is preferably 15 seconds to 5 minutes. The extension treatment in water is preferably carried out after dyeing treatment.

The stretch ratio (maximum stretch ratio) of the laminate is preferably 4.0 times or more, and more preferably 5.0 times or more with respect to the original length of the laminate. Such a high extension ratio can be achieved, for example, by using an underwater extension method (boric acid underwater extension). In addition, the "maximum stretch magnification" in this specification means the stretch magnification before the laminate is broken, and it is a value that is 0.2 lower than its value after confirming the stretch magnification of the laminate when broken.

(Insoluble treatment) The above-mentioned insoluble treatment can be performed by immersing the PVA-based resin layer in an aqueous solution of boric acid. Especially when the underwater extension method is adopted, water resistance can be imparted to the PVA-based resin layer by performing insolubilization treatment. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight relative to 100 parts by weight of water. The liquid temperature of the insoluble bath (boric acid aqueous solution) is preferably 20 ° C to 40 ° C. The insolubilization treatment is preferably carried out after the laminate is manufactured or before dyeing treatment or water extension treatment.

(Cross-linking treatment) The above-mentioned cross-linking treatment can be performed by immersing the PVA-based resin layer in a boric acid aqueous solution. By performing the cross-linking treatment, the PVA-based resin layer can be given water resistance. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight relative to 100 parts by weight of water. In addition, when the cross-linking treatment is performed after the above-mentioned dyeing treatment, it is preferable to further blend iodide. By blending iodide, the elution of iodine that has been adsorbed to the PVA-based resin layer can be suppressed. The blending amount of iodide is preferably 1 part by weight to 5 parts by weight relative to 100 parts by weight of water. Specific examples of iodide are the same as described above. The liquid temperature of the cross-linking bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Cross-linking treatment should be carried out before extension treatment in water. According to a suitable embodiment, the dyeing treatment, the cross-linking treatment, and the water extension treatment are sequentially performed.

(Washing treatment) The above-mentioned washing treatment is representatively performed by immersing the PVA-based resin layer in an aqueous potassium iodide solution.

(Drying treatment) The drying temperature in the drying treatment should be 30 ℃ ~ 100 ℃.

B-4. Others The above-mentioned polarizing plate may have a protective film disposed on the opposite side to the side of the polarizing film where the resin substrate is disposed. Examples of materials for forming the protective film include: (meth) acrylic resins, cellulose resins such as diacetyl cellulose and triethyl cellulose, olefin resins such as cycloolefin resins, polypropylene, and polyparaphenylene terephthalate Ester resins such as ethylene formate resins, polyamide resins, polycarbonate resins and copolymer resins thereof. The thickness of the protective film should be 10μm ~ 100μm. The protective film may be laminated on the polarizing film via an adhesive layer, or may be laminated in close contact (without the adhesive layer). The next layer can be formed with an adhesive or an adhesive.

The polarizing plate can be mounted on a liquid crystal display device, for example. In this case, the polarizing film is preferably placed on the liquid crystal element side of the resin substrate. With this configuration, the influence of the phase difference that the resin substrate may have on the image characteristics of the resulting liquid crystal display device can be excluded. Examples

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. In addition, the thickness measurement method is as follows. In addition, "parts" and "%" in the following examples and comparative examples represent "parts by weight" and "% by weight", respectively. (Thickness) The measurement was performed using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").

[Example 1] As a resin substrate, a long-shaped amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thick: 100μm). After corona treatment was applied to one side of the resin substrate, a mixed liquid (solid content concentration 4.0%) was applied to the corona treated surface so that the thickness after drying was 2000 nm, and dried at 60 ° C for 3 minutes to form an undercoat , This mixed liquid system modified acetoacetylate PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMERTM Z200"), degree of polymerization 1200, saponification degree 99.0 mol% or more, acetoacetylate modification degree 4.6 %) 4.0% aqueous solution, modified polyolefin resin aqueous dispersion (manufactured by Unitika Ltd., trade name "ARROWBASE SE1030N", solid content concentration 22%) and pure water are mixed. Here, the blending ratio of the solid content of the acetyl-acetyl-modified PVA and the modified polyolefin of the mixed liquid is 30:70. Next, the surface of the undercoat layer was corona-treated, and then the corona-treated surface was coated with polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetonitrile at a ratio of 9: 1 at 25 ° C. Acetoyl-modified PVA (polymerization degree 1200, acetoacetyl-modified degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMERTM Z200") and dried. A PVA-based resin layer with a thickness of 11 μm was formed. In this way, a laminate is produced.

In the oven at 120 ° C, the resulting laminate was uniaxially stretched to 2.0 times (air-assisted extension) toward the free end of the longitudinal direction (longitudinal direction) between the rollers with different turnover rates. Next, the laminate was immersed in an insoluble bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30 ° C for 30 seconds (insoluble treatment). Next, it was immersed in a dyeing bath at a liquid temperature of 30 ° C, and at the same time, the iodine concentration and the immersion time were adjusted so that the obtained polarizing plate had a predetermined transmittance. In this example, it was immersed in an aqueous iodine solution for 60 seconds. The aqueous iodine solution was obtained by blending 0.2 parts by weight of iodine and 1.0 parts by weight of potassium iodide in 100 parts by weight of water (dyeing treatment). Then, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 30 ° C (crosslinking treatment). After that, the laminate is immersed in a boric acid aqueous solution at a liquid temperature of 70 ° C (aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water and 5 parts by weight of potassium iodide), and at the same time, rolls with different turnover rates In the longitudinal direction (longitudinal direction), uniaxial stretching (in-water stretching) is performed so that the total stretching magnification becomes 5.5 times. Then, the laminate was immersed in a washing bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 30 ° C (washing treatment). In this way, a laminate (polarizing plate) in which a polarizing film with a thickness of 5 μm is formed on one side of a resin substrate with a thickness of 30 μm can be obtained.

[Example 2] A polarizing plate was produced in the same manner as in Example 1, except that the above mixed liquid was applied so that the thickness after drying was 1000 nm.

[Example 3] A polarizing plate was produced in the same manner as in Example 1, except that the above mixed liquid was applied so that the thickness after drying was 500 nm.

[Example 4] A polarizing plate was produced in the same manner as in Example 1, except that the blending ratio of the solid content of the acetoxyethyl modified PVA and the modified polyolefin in the mixed solution was changed to 50:50.

[Example 5] In the formation of the undercoat layer, in addition to the use of a 4.0% aqueous solution of acetoacetyl modified PVA (GOHSEFIMERTM Z200), a modified polyolefin resin aqueous dispersion (manufactured by Unitika Ltd., trade name "ARROWBASE SD1030N") A polarizing plate was prepared in the same manner as in Example 1 except for a mixed solution (solid content concentration: 4.0%) mixed with pure water (solid content concentration: 4.0%).

[Example 6] In the formation of the undercoat layer, in addition to the use of a 4.0% aqueous solution of acetyl-acetyl-modified PVA (GOHSEFIMERTM Z200), a modified polyolefin resin aqueous dispersion (manufactured by Unitika Ltd., trade name "ARROWBASE SE1035NJ2") , 22% of solid content) and a mixed liquid (solid content concentration of 4.0%) mixed with pure water, a polarizing plate was produced in the same manner as in Example 4.

[Example 7] In the formation of the undercoat layer, in addition to the use of acetoacetate modified PVA (manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMERTM Z410"), degree of polymerization 2200, degree of saponification 97.5 to 98.5%, acetoacetyl 4.0% aqueous solution of acetyl-based modification (4.6%), modified polyolefin resin aqueous dispersion (manufactured by Unitika Ltd., trade name "ARROWBASE SE1030N", solid content concentration 22%) and pure water (solid) Except for the component concentration of 4.0%), a polarizing plate was produced in the same manner as in Example 1.

[Example 8] A resin substrate having a thickness of 37 μm was formed on one side with a thickness of 37 μm in the same manner as in Example 1, except that the extension magnification of the air-assisted extension was changed to 4.0 times without insolubilization treatment or water extension Polarizer with 6μm polarizing film.

[Comparative Example 1] A polarizing plate was produced in the same manner as in Example 1, except that the undercoat layer was not formed and the PVA-based resin coating layer was directly formed on the resin substrate.

[Comparative Example 2] A polarizing plate was produced in the same manner as in Example 8 except that the undercoat layer was not formed and the PVA-based resin coating layer was directly formed on the resin substrate.

[Comparative Example 3] When forming the undercoat layer, a polarizing plate was produced in the same manner as in Example 3, except that a 4.0% aqueous solution of acetylacetoyl modified PVA (GOHSEFIMERTM Z200) was used.

[Comparative Example 4] When forming the undercoat layer, a polarizing plate was produced in the same manner as in Example 2 except that a 4.0% aqueous solution of acetylacetyl modified PVA (GOHSEFIMERTM Z200) was used.

[Comparative Example 5] When forming an undercoat layer, a polarizing plate was produced in the same manner as in Example 1, except that a 4.0% aqueous solution of acetylacetoyl modified PVA (GOHSEFIMERTM Z200) was used.

[Comparative Example 6] When forming an undercoat layer, the mixture solution was applied in the same manner as in the example except that a 4.0% aqueous solution of acetyl-acetyl-modified PVA (GOHSEFIMERTM Z200) was used and the thickness was 1000 nm after drying. 8 A polarizing plate was produced in the same way.

[Comparative Example 7] When forming the undercoat layer, a polarizing plate was produced in the same manner as in Example 3 except that a polyester water-based latex resin (manufactured by Unitika Ltd., trade name "Elitel KT0507E6") was used.

[Comparative Example 8] When forming the undercoat layer, a polarizing plate was produced in the same manner as in Example 2 except that a polyester water-based latex resin (manufactured by Unitika Ltd., trade name "Elitel KT0507E6") was used.

[Comparative Example 9] When forming the undercoat layer, a polarizing plate was produced in the same manner as in Example 2 except that the modified polyolefin resin aqueous dispersion (ARROWBASE SB1035NJ2) was used.

[Comparative Example 10] When forming an undercoat layer, in addition to using a mixed solution of 10 g of a 4.0% aqueous solution of acetyl-acetyl modified PVA (GOHSEFIMERTM Z200) and 62.5 g of a polyester aqueous latex resin (Elitel KT0507E6), A polarizing plate was produced in the same manner as in Example 3. Here, the blending ratio of the solid content of the acetyl acetyl modified PVA and polyester in the mixed solution is 50:50.

[Comparative Example 11] When forming an undercoat layer, in addition to using a mixture of 10 g of a 4.0% aqueous solution of acetylated acetyl-modified PVA (GOHSEFIMERTM Z200) and 62.5 g of a polyester aqueous latex resin (Elitel KT0507E6), A polarizing plate was produced in the same manner as in Example 1. Here, the blending ratio of the solid content of the acetyl acetyl modified PVA and polyester in the mixed solution is 50:50.

(Evaluation) The following evaluations were made for the above examples and comparative examples. The evaluation results are integrated in Table 1. In addition, the results of SEM observation (6500 times) of the cross-sections of the laminate after the extension of Example 1, Example 2, Example 8, Comparative Example 1, and Comparative Example 11 are shown in FIG. 1. 1. Adhesion The adhesion is evaluated by measuring the PVA peel force and the substrate peel force. The measuring methods of PVA peel force and substrate peel force are as follows. (PVA peeling force) The obtained polarizing plate is coated with an adhesive on the surface side of the resin substrate and bonded to the glass plate, and a reinforcing polyimide tape (made by Nitto Denko Co., Ltd.) Acetylimide adhesive tape No. 360A) to prepare a sample for measurement. Place a slit between the polarizing film and the resin substrate of the measurement sample with a cutting knife to make the polarizing film and reinforcing polyimide tape stand upright with respect to the surface of the resin substrate to form a 90 ° angle, and the angle is not limited The adhesion / film peeling analysis device "VPA-2" (manufactured by Kyowa Interface Chemical Co., Ltd.) measures the force (N / 15mm) required for peeling at a peeling speed of 3000 mm / min. (Substrate peeling force) The obtained polarizing plate was coated with an adhesive on the polarizing film surface side and bonded to a glass plate to prepare a sample for measurement. Insert a slit between the polarizing film and the resin substrate of the measurement sample with a cutting knife, make the resin substrate stand upright with respect to the polarizing film surface to form a 90 ° angle, and measure the peeling speed with the above "VPA-2" The required force (N / 15mm) for peeling at 3000mm / min. 2. Appearance When forming the primer layer and applying the polyvinyl alcohol solution, visually observe the appearance of the coating film.

[Table 1]

As shown in Table 1, the laminates of the examples have good adhesion and appearance. Even if the extension in water is implemented, sufficient adhesion can be maintained. In addition, Comparative Examples 1 and 2 in which no undercoat layer was formed did not achieve sufficient adhesion. Comparative Examples 3 to 6 that do not use polyolefin-based components to form an undercoat layer not only did not achieve sufficient adhesion, but also contracted and formed when the undercoat layer thickened (when applied) as the undercoat layer thickened. The constriction becomes air bubbles, which deteriorates the appearance. In Comparative Examples 7 to 9 in which an undercoat layer was formed without using a polyvinyl alcohol-based component, the coating film was cloudy when the undercoat layer was formed, and a good appearance was not obtained. In Comparative Examples 10 and 11 in which an undercoat layer was formed using a polyvinyl alcohol-based component and a polyester-based component, aggregates (protrusions) were formed on the undercoat layer, and a good appearance was not obtained. Industrial availability

The laminate of the present invention is suitable for use in, for example, image display devices. Specifically suitable for use as LCD panels and organic EL devices for LCD TVs, LCD monitors, mobile phones, digital cameras, video cameras, portable game consoles, car navigation, copiers, printers, fax machines, clocks, electronic microwave ovens, etc. The anti-reflective plate, etc.

FIG. 1 is an SEM observation photograph of a cross section of a laminate in Examples and Comparative Examples.

Claims (13)

A laminate having a resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate ; The aforementioned intermediate region contains a polyvinyl alcohol-based component and a polyolefin-based component. The laminated body according to claim 1, wherein the polyvinyl alcohol-based component contains acetoxyethyl-modified polyvinyl alcohol. The laminate according to claim 1 or 2, wherein the blending ratio of the polyvinyl alcohol-based component and the polyolefin-based component is 5:95 to 60:40. The laminated body according to claim 1 or 2, wherein the thickness of the aforementioned intermediate region is 100 nm to 1000 nm. A method for manufacturing a laminate, comprising the steps of: applying a composition for forming an undercoat layer containing a polyolefin-based component to one side of a resin substrate to form an undercoat layer; and coating a polymer-containing layer on the surface of the aforementioned undercoat layer A coating solution of a vinyl alcohol-based resin forms a coating layer of a polyvinyl alcohol-based resin; and the composition for forming an undercoat layer contains a polyvinyl alcohol-based component and a polyolefin-based component. The method for manufacturing a laminate according to claim 5, wherein the polyvinyl alcohol-based component contains acetoxyethyl-modified polyvinyl alcohol. The method for manufacturing a laminate according to claim 5 or 6, wherein the blending ratio of the solid component of the polyvinyl alcohol-based component and the polyolefin-based component is 5:95 to 60:40. The method for manufacturing a laminate according to claim 5 or 6, wherein the thickness of the aforementioned undercoat layer is 500 nm to 3000 nm. A method of manufacturing a polarizing plate, which includes the steps of extending and dyeing a laminate, and the laminate system is manufactured using the manufacturing method of claim 5. A polarizing plate having a resin base material and a polyvinyl alcohol-based resin layer formed on one side of the resin base material, the resin base material side of the polyvinyl alcohol-based resin layer is considered to have an intermediate region of a polyolefin-based component The intermediate region contains a polyvinyl alcohol-based component and a polyolefin-based component, and the polyvinyl alcohol-based resin layer is an oriented polarizing film that adsorbs a dichroic substance. The polarizing plate according to claim 10, wherein the aforementioned polyvinyl alcohol-based component contains acetylacetyl-modified polyvinyl alcohol. The polarizing plate according to claim 10 or 11, wherein the blending ratio of the polyvinyl alcohol-based component and the polyolefin-based component is 5: 95 ~ 60: 40. The polarizing plate according to claim 10 or 11, wherein the thickness of the aforementioned intermediate region is 100 nm to 1000 nm.