JP6376597B2 - Laminate for manufacturing polarizing film - Google Patents

Description

  The present invention relates to a laminate used for manufacturing a polarizing film.

  There has been proposed a method of obtaining a polarizing film by forming a polyvinyl alcohol-based resin layer on a resin substrate and stretching and dyeing the laminate (for example, Patent Document 1). According to such a method, a polarizing film having a small thickness can be obtained, and thus, for example, it has been attracting attention as being able to contribute to a reduction in thickness of an image display device. However, when a resin base material is used, there is a problem that a poor appearance tends to occur in the obtained polarizing film.

JP 2000-338329 A

  The present invention has been made to solve the above-described conventional problems, and a main object thereof is to provide a laminate capable of producing a polarizing film having an excellent appearance.

The laminate of the present invention is used for the production of a polarizing film, and is a long, polyvinyl alcohol resin film containing a polyvinyl alcohol resin, and a resin substrate disposed on one side of the polyvinyl alcohol resin film. And a knurling projecting from one side is formed.
In one embodiment, the knurling is formed so as to protrude toward the resin substrate.
In one embodiment, the knurling is provided at the end in the width direction.
In one embodiment, the knurling formation region extends in the longitudinal direction.
In one embodiment, the height of the knurling is 5 μm to 15 μm.
In one embodiment, the width is 1500 mm to 2700 mm.
In one embodiment, the polyvinyl alcohol resin film is stretched.
According to another situation of this invention, the manufacturing method of a polarizing film is provided. This manufacturing method of a polarizing film includes a step of cutting a knurling formation portion of the laminate and a step of stretching the laminate in this order.
In one embodiment, the stretching is underwater stretching.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body provided with the knurling which provided the polyvinyl alcohol-type resin film and the resin base material arrange | positioned at the one side of this polyvinyl-alcohol-type resin film, and protruded from one surface is provided. Even if such a laminated body is wound up in a roll shape in the manufacturing process, generation of winding tightening (gauge band) and wrinkles is prevented. As a result, a polarizing film excellent in appearance can be produced.

It is an appearance top view of a layered product by one embodiment of the present invention. It is a figure which shows the formation method of the knurling of the laminated body shown in FIG.

  Hereinafter, although one embodiment of the present invention is described, the present invention is not limited to these embodiments.

A. Laminate FIGS. 1 and 2 are schematic views of a laminate for producing a polarizing film according to one embodiment of the present invention, FIG. 1 is an external plan view of the laminate, and FIG. 2 is a laminate shown in FIG. It is a figure which shows the formation method of the knurling of a body. The laminate 10 includes a long polyvinyl alcohol resin (hereinafter referred to as “PVA resin”) film 12 and a resin base material 11 disposed on one side of the PVA resin film 12. The width of the PVA-based resin film 12 can be set to be substantially the same as the width of the resin base material 11 or smaller than the width of the resin base material 11. The laminated body 10 is formed with a knurling 13 projecting from one surface thereof. The knurling 13 is preferably formed in a portion where the PVA resin film 12 and the resin base material 11 overlap. In the illustrated example, the knurling 13 is intermittently formed at both ends in the width direction of the stacked body 10, and the knurling formation region 20 in which the knurling 13 is arranged extends in the longitudinal direction. In the present specification, “knurling” refers to a concavo-convex structure formed on the surface of a laminate.

  The knurling 13 may be formed so as to protrude toward the resin base material 11 or may be formed so as to protrude toward the PVA resin film 12 side. Thus, the knurling can be satisfactorily formed in the laminate 10.

  The width of the laminate (resin base material) can be set to any appropriate value. Typically, it is 800 mm or more, preferably 1500 mm to 2700 mm. From the viewpoint of yield, the knurling is preferably formed at a position of 5 mm to 10 mm from the side edge in the width direction of the laminate (resin base material). The width of the knurling region is preferably 5 mm to 30 mm. The ratio of the width of the knurling region to the width of the laminate is preferably 0.7% to 1.5%.

  Any appropriate shape can be adopted as the shape of each knurling. Specific examples of the three-dimensional shape of each knurling (convex part) include a cube, a rectangular parallelepiped, a cone, a pyramid (triangular pyramid, quadrangular pyramid), a dome (hemispherical), and a trapezoid (conical frustum, truncated pyramid). It is done. Unlike the illustrated example, the knurling may be formed continuously (in a series) along the longitudinal direction. In this case, examples of the cross-sectional shape viewed from the longitudinal direction of the knurling include a quadrangle (rectangle, square, trapezoid), a triangle, and a dome shape (semicircle).

  The height of the knurling (the height from the surface of the laminate in the non-knurling region) is preferably 5 μm to 15 μm. The ratio of the height of the knurling to the thickness of the resin substrate described later is preferably 5% to 40%.

A-1. PVA resin film Any appropriate resin can be adopted as the PVA resin for forming the PVA resin film. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. An ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The degree of saponification of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. . The saponification degree can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizing film having excellent durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.

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

  The thickness of the PVA-based resin film is, for example, 20 μm or less, preferably 15 μm or less. On the other hand, the thickness of the PVA resin film is preferably 5 μm or more.

  The PVA-based resin film is typically formed by applying a coating liquid containing a PVA-based resin on the coating surface. A typical example of the coating solution is a solution obtained by dissolving a PVA resin in a solvent. Examples of the solvent for dissolving the PVA resin include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polymethyl alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. Used. These may be used alone or in combination of two or more. Among these, water is preferable. The PVA resin concentration of the solution can be set to any appropriate value. For example, it is set according to the polymerization degree or saponification degree of the PVA resin. The concentration of the PVA resin in the solution is, for example, 3 to 20 parts by weight with respect to 100 parts by weight of the solvent.

  The coating solution may contain an additive. Examples of the additive include a plasticizer and a surfactant. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability and stretchability of the resulting PVA resin film. Moreover, as an additive, an easily bonding component is mentioned, for example. By using the easy-adhesive component, the adhesion between the resin base material and the PVA-based resin film can be improved. As a result, for example, problems such as peeling of the PVA-based resin film from the resin base material can be suppressed, and dyeing and underwater stretching described later can be performed satisfactorily. As the easily adhesive component, for example, modified PVA such as acetoacetyl-modified PVA is used.

  As a coating method of the coating solution, any appropriate method can be adopted depending on the form of the coating surface. Examples thereof include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, and a knife coating method (such as a comma coating method). The coating / drying temperature of the coating solution is, for example, 20 ° C. or higher, preferably 50 ° C. or higher.

  In one embodiment, the PVA resin film is stretched. Any appropriate method can be adopted as a method for stretching the PVA-based resin film. In addition, the stretching direction of the PVA resin film can be selected in any appropriate direction.

A-2. Resin Base Material Any appropriate material can be adopted as a constituent material of the resin base material. Examples thereof include ester resins such as polyethylene terephthalate resins, cycloolefin resins, olefin resins such as polypropylene, (meth) acrylic resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. Preferably, a polyethylene terephthalate resin is used. Among these, amorphous polyethylene terephthalate resin is preferably used. Specific examples of the amorphous polyethylene terephthalate resin include a copolymer further containing isophthalic acid as a dicarboxylic acid, and a copolymer further containing cyclohexanedimethanol as a glycol.

  The resin base material preferably has an elastic modulus higher than the elastic modulus (for example, indentation elastic modulus) of the PVA resin film. By using such a resin base material, knurling can be formed satisfactorily. Specifically, it may be difficult to form the knurling in the state of the PVA resin film alone, but the knurling can be satisfactorily formed by forming a laminated structure with the resin base material.

  The glass transition temperature (Tg) of the resin substrate is preferably 120 ° C. or lower, more preferably 100 ° C. or lower. This is because, when the laminate is stretched, stretchability (particularly in water stretching) can be sufficiently secured while suppressing crystallization of the PVA-based resin film. As a result, a polarizing film having excellent optical characteristics (for example, the degree of polarization) can be manufactured. On the other hand, the glass transition temperature of the resin substrate is preferably 60 ° C. or higher. In addition, a glass transition temperature (Tg) is a value calculated | required according to JISK7121.

  The water absorption rate of the resin base material is preferably 0.2% or more, and more preferably 0.3% or more. Such a resin base material absorbs water, and the water can act as a plasticizer to be plasticized. As a result, the stretching stress can be greatly reduced and the stretchability can be excellent. On the other hand, the water absorption rate of the resin base material is preferably 3.0% or less, more preferably 1.0% or less. By using such a resin base material, it is possible to prevent problems such as the dimensional stability of the resin base material being significantly reduced during production and the appearance of the resulting polarizing film being deteriorated. Moreover, it can prevent that it breaks at the time of extending | stretching in water, or a PVA-type resin film peels from a resin base material. In addition, a water absorption is a value calculated | required according to JISK7209.

  The thickness of the resin substrate is preferably 20 μm or more, more preferably 50 μm or more. By using such a resin base material, knurling can be formed satisfactorily. On the other hand, the thickness of the resin substrate is preferably 300 μm or less, and more preferably 200 μm or less.

  The surface of the resin base material may be subjected to surface modification treatment (for example, corona treatment) or an easy-adhesion layer may be formed. According to such a process, the laminated body excellent in the adhesiveness of a resin base material and a PVA-type resin film can be obtained. Moreover, the functional layer (for example, antistatic layer) may be formed in the side by which the PVA-type resin film of a resin base material is not arrange | positioned. By forming the functional layer, blocking resistance can be imparted.

A-3. Method for Producing Laminate A laminate of a PVA-based resin film and a resin base material can be produced by any appropriate method. For example, a method of forming a PVA-based resin film on a resin base material and a method of laminating a resin base material on a separately formed PVA-based resin film can be mentioned. When a PVA resin film is formed on a resin substrate, the coated surface is a resin substrate. When a PVA-based resin film is separately formed, the PVA-based resin film and the resin base material may be laminated via an adhesive layer (using an adhesive or a pressure-sensitive adhesive) or in close contact (substantially) You may laminate | stack (without using an adhesive agent or an adhesive).

  As described above, when the PVA-based resin film is stretched, the stretching is preferably performed on a laminate of the PVA-based resin film and the resin base material. In one embodiment, a laminate of a PVA resin film and a resin base material is stretched in the longitudinal direction by an air stretching method. A draw ratio is 1.5 times or more and 3.5 times or less, for example. The stretching temperature is, for example, 95 ° C to 150 ° C.

  The knurling may be formed by any suitable method. In one embodiment, as illustrated, a protrusion formed on the peripheral surface of the knurling roller 31 by nipping the stack 10 between the knurling roller 31 and the support roller 32 while conveying the stack 10 in the longitudinal direction. A knurling (uneven structure) 13 is formed by pressing 31 a against the laminate 10. Although not shown, the pressing force and the peripheral surface temperature of the knurling roller pair 31, 32 are appropriately adjusted. In the illustrated example, a knurling roller 31 is pressed against the resin base material 11 to form a knurling 13 protruding from the surface of the resin base material 11. Rather than pressing the knurling roller against the PVA resin film side, the knurling can be satisfactorily formed by pressing the knurling roller against the resin substrate side as shown in the example of the drawing.

  The knurling can be formed at any suitable timing. In the illustrated example, knurling is formed on the laminate of the PVA resin film and the resin base material. However, unlike the illustrated example, the knurling is formed on the resin base material, and then the PVA resin film is formed. Or you may laminate.

A-4. Others In one embodiment, the laminate is wound into a roll. The winding tension is typically 300N to 600N. The winding may be performed so that the PVA-based resin film is on the inner side (core material side), or may be performed so that the PVA-based resin film is on the outer side. In the manufacturing process of the polarizing film, the laminate of the PVA-based resin film and the resin base material can be stored (leaved) in the wound state, but a partial film on the laminate (mainly the resin base material). If the thickness is uneven, winding and wrinkling occur when the film is wound, leading to a decrease in the appearance of the resulting polarizing film. Such a problem becomes more prominent as the storage period becomes longer. Even if the laminated body of the present invention is wound in a roll shape, it is possible to prevent the occurrence of winding and wrinkling. As a result, a polarizing film excellent in appearance can be produced.

  The frequency of occurrence of the tightening may vary according to the thickness distribution in the width direction of the laminate (mainly the resin base material). Specifically, even if the thickness difference of the entire laminate (mainly, the resin base material) is small, if thickness unevenness is partially generated, winding can be caused by winding. Therefore, in one embodiment, the height of the knurling can be set higher than the thickness variation of the resin base material. Preferably, the height (average height) of the knurling is set to be higher than the thickness variation (30 mm width) of the resin base material.

B. Polarizing Film The polarizing film is produced by performing a treatment for using the PVA-based resin film of the laminate as a polarizing film. Examples of the treatment for forming the polarizing film include dyeing treatment, stretching treatment, insolubilization treatment, crosslinking treatment, washing treatment, and drying treatment. These processes can be appropriately selected depending on the purpose. Further, the processing order, the processing timing, the number of processings, and the like can be set as appropriate. The knurling portion of the laminate can be cut at any suitable time. In one embodiment, a stretching process is performed on the laminate from which the knurling portion has been cut. Any appropriate method can be adopted as a method for cutting the knurling portion. Specifically, when a knurling is formed at the end in the width direction of the laminated body as shown in the drawing, the knurling forming portion is cut by cutting (slit) the end in the width direction of the laminated body. Examples of the cutting means include a cutting blade such as a round blade and a dish blade, and a laser. Hereinafter, the various processes will be described.

(Dyeing process)
The dyeing process is typically performed by dyeing a PVA resin film with a dichroic substance. Preferably, the dichroic substance is adsorbed on the PVA resin film. Examples of the adsorption method include a method of immersing a PVA resin film (laminate) in a staining liquid containing a dichroic substance, a method of applying the staining liquid to a PVA resin film, and a method of applying the staining liquid to a PVA system. Examples include a method of spraying on a resin film. Preferably, it is a method of immersing the laminate in the staining solution. It is because a dichroic substance can adsorb | suck favorably.

  Examples of the dichroic substance include iodine and organic dyes. These may be used alone or in combination of two or more. The dichroic material is preferably iodine. When iodine is used as the dichroic substance, the staining solution is preferably an iodine aqueous solution. The compounding amount of iodine is preferably 0.1 part by weight to 0.5 part by weight with respect to 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add an iodide to the aqueous iodine 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. Etc. Among these, potassium iodide is preferable. The blending amount of iodide is preferably 0.02 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of water.

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

(Extension process)
Any appropriate method can be adopted as a method for stretching the laminate. Specifically, it may be fixed end stretching (for example, a method using a tenter stretching machine) or free end stretching (for example, a method of uniaxial stretching through a laminate between rolls having different peripheral speeds). Moreover, simultaneous biaxial stretching (for example, a method using a simultaneous biaxial stretching machine) or sequential biaxial stretching may be used. The stretching of the laminate may be performed in one stage or in multiple stages.

  The stretching treatment may be an underwater stretching method performed by immersing the laminate in a stretching bath, or an air stretching method. Preferably, the underwater stretching treatment is performed at least once, and more preferably, the underwater stretching treatment and the air stretching treatment are combined. According to the stretching in water, the PVA resin film can be stretched at a temperature lower than the glass transition temperature (typically about 80 ° C.) of the resin base material or the PVA resin film while suppressing its crystallization. It can be stretched at a high magnification. As a result, a polarizing film having excellent optical characteristics (for example, the degree of polarization) can be manufactured. In addition, when combining an underwater extending | stretching process and an air extending | stretching process, the air extending | stretching process with respect to the above-mentioned laminated body may be sufficient as an in-air extending | stretching process.

  Any appropriate direction can be selected as the stretching direction of the laminate. In one embodiment, it extends | stretches in the longitudinal direction of an elongate laminated body. Specifically, the laminate is transported in the longitudinal direction, which is the transport direction (MD). In another embodiment, it extends | stretches in the width direction of an elongate laminated body. Specifically, the laminate is transported in the longitudinal direction, and the direction (TD) is orthogonal to the transport direction (MD).

  The stretching temperature of the laminate can be set to any appropriate value depending on the resin base material, the stretching method, and the like. When adopting the air stretching method, the stretching temperature is preferably equal to or higher than the glass transition temperature (Tg) of the resin substrate, more preferably the glass transition temperature (Tg) of the resin substrate + 10 ° C., and particularly preferably Tg + 15 ° C. That's it. On the other hand, the stretching temperature of the laminate is preferably 170 ° C. or lower. By stretching at such a temperature, it is possible to suppress rapid crystallization of the PVA-based resin and to suppress defects due to the crystallization (for example, preventing the orientation of the PVA-based resin film due to stretching). it can.

  When the underwater stretching method is adopted as the stretching method, the liquid temperature of the stretching bath is preferably 40 ° C to 85 ° C, more preferably 50 ° C to 85 ° C. If it is such temperature, it can extend | stretch at high magnification, suppressing melt | dissolution of a PVA-type resin film. Specifically, as described above, the glass transition temperature (Tg) of the resin base material is preferably 60 ° C. or higher in relation to the formation of the PVA-based resin film. In this case, when the stretching temperature is lower than 40 ° C., there is a possibility that the stretching cannot be satisfactorily performed even in consideration of plasticization of the resin base material with water. On the other hand, the higher the temperature of the stretching bath, the higher the solubility of the PVA-based resin film, which may result in failure to obtain excellent optical properties.

  When employing an underwater stretching method, it is preferable to stretch the laminate by immersing it in an aqueous boric acid solution (stretching in boric acid in water). By using a boric acid aqueous solution as the stretching bath, the PVA resin film can be provided with rigidity that can withstand the tension applied during stretching and water resistance that does not dissolve in water. Specifically, boric acid can form a tetrahydroxyborate anion in an aqueous solution and crosslink with a PVA resin by hydrogen bonding. As a result, rigidity and water resistance can be imparted to the PVA-based resin film, the film can be stretched well, and a polarizing film having excellent optical properties can be produced.

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

  Preferably, an iodide is blended in the stretching bath (boric acid aqueous solution). By blending iodide, elution of iodine adsorbed on the PVA resin film can be suppressed. Specific examples of the iodide are as described above. The concentration of iodide is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 8 parts by weight with respect to 100 parts by weight of water.

  The immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes. The draw ratio of the laminate by the underwater drawing method is, for example, 2 times or more. The underwater stretching treatment is preferably performed after the dyeing treatment.

(Insolubilization treatment)
The insolubilization treatment is typically performed by immersing a PVA resin film in an aqueous boric acid solution. In particular, when an underwater stretching method is employed, water resistance can be imparted to the PVA-based resin film by performing insolubilization treatment. The concentration of the boric acid aqueous solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20 ° C to 40 ° C. Preferably, the insolubilization treatment is performed before the dyeing treatment or the underwater stretching treatment.

(Crosslinking treatment)
The crosslinking treatment is typically performed by immersing a PVA resin film in an aqueous boric acid solution. By performing the crosslinking treatment, water resistance can be imparted to the PVA resin film. The concentration of the boric acid aqueous solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water. Moreover, when performing a crosslinking process after the said dyeing | staining process, it is preferable to mix | blend an iodide further. By blending iodide, elution of iodine adsorbed on the PVA resin film can be suppressed. The blending amount of iodide is preferably 1 part by weight to 5 parts by weight with respect to 100 parts by weight of water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Preferably, the crosslinking treatment is performed before the underwater stretching treatment. In a preferred embodiment, the dyeing process, the crosslinking process and the underwater stretching process are performed in this order.

(Cleaning process)
The cleaning treatment is typically performed by immersing a PVA resin film in an aqueous potassium iodide solution.

(Drying process)
The drying temperature in the drying process is preferably 30 ° C to 100 ° C.

  The obtained polarizing film is substantially a PVA resin film in which a dichroic substance is adsorbed and oriented. The thickness of the polarizing film is preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less. On the other hand, the thickness of the polarizing film is preferably 0.5 μm or more, more preferably 1.0 μm or more.

  The polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizing film is preferably 40.0% or more, more preferably 41.0% or more, further preferably 42.0% or more, and particularly preferably 43.0% or more. The polarization degree of the polarizing film is preferably 99.8% or more, more preferably 99.9% or more, and further preferably 99.95% or more.

C. Polarizing plate The polarizing plate of the present invention has the polarizing film. Preferably, the polarizing plate includes the polarizing film and a protective film disposed on at least one side of the polarizing film. As the protective film, the resin base material may be used as it is, or a film different from the resin base material may be used. Examples of the material for forming the protective film include (meth) acrylic resins, cellulose resins such as diacetyl cellulose and triacetyl cellulose, cycloolefin resins, olefin resins such as polypropylene, and ester resins such as polyethylene terephthalate resins. , Polyamide resins, polycarbonate resins, and copolymer resins thereof. The thickness of the protective film is preferably 10 μm to 100 μm.

  In one embodiment, the said resin base material is peeled from a polarizing film, and another film is laminated | stacked. The protective film may be laminated on the polarizing film via an adhesive layer, or may be laminated in close contact (without an adhesive layer). The adhesive layer is typically formed of an adhesive or a pressure-sensitive adhesive.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the measuring method of the variation in the thickness of the resin base material and the average height of the knurling is as follows.
1. Variation in thickness of resin base material Using a contact-type desktop offline thickness measuring device (YAMABUN TOF-5R, manufactured by Yamabun Denki Co., Ltd.), the thickness is measured at a pitch of 5 mm in the width direction of the resin base material. The thickness variation in the whole width direction and 30 mm width was evaluated.
2. Average height of knurling Using a film thickness measuring machine (manufactured by Mahr), ten knurling portions were measured at a 1 cm pitch, and the average value of the measured values was calculated.

[Example 1]
(Production of laminate)
Corona treatment was performed on one side of a long, 100 μm thick resin substrate made of amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) having a water absorption of 0.75% and Tg of 75 ° C. On this corona-treated surface, polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more) , Manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “Gosefimer Z200”) was applied at 25 ° C. and dried at 60 ° C. for 200 seconds to form a PVA resin film having a thickness of 10 μm. Formed. The laminate thus obtained was stretched uniaxially at the free end by 2.0 times in the longitudinal direction between rolls having different peripheral speeds in an oven at 115 ° C. (in-air stretching).
Thereafter, a knurling as shown in FIG. 1 is formed on each of both ends in the width direction of the laminate (at a position of 5 mm to 7 mm from the edge of the resin base) using a knurling roller pair as shown in FIG. A laminate was obtained. The average height of the formed knurling from the resin base material surface was 9.12 μm.

[Example 2]
A laminate was obtained in the same manner as in Example 1 except that knurling having an average height from the resin substrate surface of 6.74 μm was formed.

[Example 3]
A laminate was obtained in the same manner as in Example 1 except that a knurling having an average height from the resin substrate surface of 12.59 μm was formed.

[Example 4]
A laminate was obtained in the same manner as in Example 1 except that knurling having an average height from the resin substrate surface of 4.11 μm was formed.

[Example 5]
A laminate was obtained in the same manner as in Example 1 except that knurling having an average height from the resin substrate surface of 15.87 μm was formed.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1 except that knurling was not formed.

(Evaluation)
About the laminated body of each Example and a comparative example, the influence by winding was evaluated. The evaluation method is as follows, and the evaluation results are shown in Table 1.
(Effect of winding)
The laminate obtained was wound up 3100 m to 3500 m in the longitudinal direction so that the PVA-based resin film was inside at a tension of 450 N to form a laminate roll, and the laminate roll immediately after winding and after 10 days passed The state was observed visually.

  In Example 5, the winding tightening was not confirmed immediately after winding and 10 days after winding, but the folding was confirmed near the center of the laminate roll immediately after winding, and the folding deteriorated after 10 days. .

  The polarizing film of the present invention is suitably used for an image display device, for example. Specifically, LCD TVs, LCDs, mobile phones, digital cameras, video cameras, portable game machines, car navigation systems, copy machines, printers, fax machines, watches, microwave ovens, etc., anti-reflection plates for organic EL devices Etc. are suitably used.

DESCRIPTION OF SYMBOLS 10 Laminated body 11 Resin base material 12 Polyvinyl alcohol (PVA) type resin film 13 Knurling

Claims (6)

A long, polyvinyl alcohol resin film containing a polyvinyl alcohol resin;
A resin substrate disposed on one side of the polyvinyl alcohol-based resin film,
A knurling protruding from one side is formed,
A laminate for producing a polarizing film,
The water absorption rate of the resin substrate is 0.2% or more and 0.75% or less,
The knurling is provided at the end in the width direction of the laminate, and is formed so as to protrude toward the resin substrate side,
The height of the knurling Ri 5μm~15μm der, and the ratio to the thickness of the resin base material is 5% to 40%, the laminated body for polarizing film production. The laminate according to claim 1, wherein the knurling formation region extends in a longitudinal direction. The laminate according to claim 1 or 2 , wherein the width is 1500 mm to 2700 mm. The laminate according to any one of claims 1 to 3 , wherein the polyvinyl alcohol-based resin film is stretched. Projected from one surface into a laminate for producing a polarizing film, which is long and includes a polyvinyl alcohol resin film containing a polyvinyl alcohol resin and a resin substrate disposed on one side of the polyvinyl alcohol resin film. Forming a knurling having a height of 5 μm to 15 μm and a ratio of 5% to 40% with respect to the thickness of the resin base material at the end in the width direction ;
Cutting the knurling formation part of the laminate;
And a step of stretching the laminate, in this order. The manufacturing method according to claim 5 , wherein the stretching is underwater stretching.

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