KR20160071332A - Laminate for producing polarizing film - Google Patents

Abstract

The purpose of the present invention is to provide a multilayer body for manufacturing a polarizing film with an excellent appearance. According to the present invention, the multilayer body (10) comprises: a long polyvinyl alcohol resin layer (12) including polyvinyl alcohol resins; a resin substrate (11) arranged on a side of the polyvinyl alcohol resin layer (12); and a nulling part (13) protruding from a surface in one direction.

Description

[0001] LAMINATE FOR PRODUCING POLARIZING FILM [0002]

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

There has been proposed a method for forming a polarizing film by forming a polyvinyl alcohol resin layer on a resin substrate and stretching and dyeing the laminate (for example, Patent Document 1). According to such a method, a thin polarizing film can be obtained, and thus it has been attracting attention that it can contribute to, for example, the thinness of an image display apparatus. However, when a resin substrate is used, there is a problem that the polarizing film obtained tends to cause appearance defects.

Japanese Patent Application Laid-Open No. 2000-338329

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a laminate capable of producing a polarizing film excellent in appearance.

The laminate of the present invention comprises a polyvinyl alcohol-based resin film used for producing a polarizing film, which is elongated and contains a polyvinyl alcohol-based resin, and a resin base material disposed on one side of the polyvinyl alcohol- A knurling protruding from the surface of the yoke is formed.

In one embodiment, the knurling is formed to protrude toward the resin base.

In one embodiment, the knurling is formed at an end portion in the width direction.

In one embodiment, the knurling forming region extends in the longitudinal direction.

In one embodiment, the knurling has a height of 5 탆 to 15 탆.

In one embodiment, the width is 1500 mm to 2700 mm.

In one embodiment, the polyvinyl alcohol-based resin film is stretched.

In one embodiment, the resin substrate contains a polyethylene terephthalate resin.

In one embodiment, it is rolled up.

According to another aspect of the present invention, a method of manufacturing a polarizing film is provided. The method for producing the polarizing film includes a step of cutting off a knurled portion of the laminate and a step of stretching the laminate.

In one embodiment, the stretching is in-water stretching.

According to the present invention, there is provided a laminated body comprising a polyvinyl alcohol-based resin film and a resin base material disposed on one side of the polyvinyl alcohol-based resin film, wherein the knurled protruding from one surface is formed. Such a laminate prevents winding (gauge band) and wrinkles from being generated even if the laminate is wound in a roll form in the manufacturing process. As a result, a polarizing film excellent in appearance can be produced.

1 is an external plan view of a laminate according to an embodiment of the present invention.
2 is a view showing a method of forming a knurling of the laminate shown in Fig.

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

A. Laminate

1 and 2 are schematic views of a laminated body for producing a polarizing film according to an embodiment of the present invention. Fig. 1 is an external plan view of a laminate, and Fig. 2 is a view showing a method of forming a knurling of the laminate shown in Fig. FIG. The laminate 10 includes a film 12 of a long-form polyvinyl alcohol resin (hereinafter referred to as " PVA resin ") and a resin substrate 11 arranged on one side of the PVA resin film 12 . The width of the PVA resin film 12 can be set to be substantially equal to the width of the resin base material 11 or smaller than the width of the resin base material 11. [ In the laminate 10, a knurl 13 protruding from one surface thereof is formed. The knurling 13 is preferably formed at a portion where the PVA resin film 12 and the resin base material 11 overlap with each other. In the illustrated example, the knurling 13 is intermittently formed at both ends in the width direction of the laminate 10, and the knurling forming area 20 in which the knurling 13 is stretched extends in the longitudinal direction. In this specification, " knurling " refers to a concavo-convex structure formed on the surface of the laminate.

The knurling 13 may be formed so as to protrude toward the resin base material 11 or may protrude toward the PVA based resin film 12. However, the knurling protrudes toward the resin base material 11 as shown in the drawing, 10 can be formed with good knurling.

The width of the laminate (resin substrate) can be set to any appropriate value. Typically, it is 800 mm or more, preferably 1500 mm to 2700 mm. Knurling is preferably formed at a position of 5 mm to 10 mm from the short side in the width direction of the laminate (resin base) in view of the yield. The width of the nulling area is preferably 5 mm to 30 mm. The ratio of the width of the knurl-forming area to the width of the laminate is preferably 0.7% to 1.5%.

Any suitable shape may be employed for the shape of the individual knurling. Specific examples of the three-dimensional shape of each knurling (convex portion) include a cube, a rectangular parallelepiped, a cone, a pyramid, a dome, and a truncated pyramid. Unlike the example shown in the drawing, the knurling may be formed continuously (in series) along the longitudinal direction. In this case, the cross-sectional shape viewed from the longitudinal direction of the knurling can be, for example, a rectangular shape (rectangular, square, trapezoidal), a triangular shape, or a dome shape (semi-circular shape).

The height of the knurling (height from the surface of the laminate in the knurl non-forming area) is preferably 5 to 15 占 퐉. The ratio of the knurling height to the thickness of the resin base material described later is preferably 5% to 40%.

A-1. PVA resin film

As the PVA-based resin forming the PVA-based resin film, any suitable resin may be employed. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The degree of saponification of the PVA resin is usually from 85 mol% to 100 mol%, preferably from 95.0 mol% to 99.95 mol%, and more preferably from 99.0 mol% to 99.93 mol%. The saponification degree can be obtained according to JIS K 6726-1994. By using such a saponification degree PVA resin, a polarizing film having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

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

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

The PVA-based resin film is typically formed by applying a coating liquid containing a PVA-based resin to a coated surface. As the coating liquid, a solution in which a PVA resin is dissolved in a solvent is exemplified. Examples of the solvent for dissolving the PVA resin include water, polyhydric alcohols such as dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols and trimethylolpropane, ethylenediamine , And diethylenetriamine. These may be used alone or in combination of two or more. Among them, water is preferable. The PVA resin concentration of the solution may be set to any suitable value. For example, the degree of polymerization and saponification degree of the PVA resin are set. The concentration of the PVA resin in the solution is, for example, 3 parts by weight to 20 parts by weight based on 100 parts by weight of the solvent.

The coating liquid may contain an additive. Examples of the additive include plasticizers, surfactants, and the like. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. The surfactant includes, for example, nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability and stretchability of the obtained PVA-based resin film. As an additive, for example, an easy-to-adhere component can be mentioned. By using the easy-to-adhere component, the adhesion between the resin substrate and the PVA-based resin film can be improved. As a result, for example, problems such as peeling of the PVA resin film from the resin base can be suppressed, and dyeing and underwater stretching described later can be satisfactorily performed. As the easy-to-adhere component, for example, modified PVA such as acetacetyl-modified PVA is used.

As a coating method of the coating liquid, any appropriate method may be adopted depending on the shape of the coating surface or the like. For example, 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 (a comma coating method) can be used. The coating and drying temperature of the coating liquid is, for example, 20 DEG C or higher, preferably 50 DEG C or higher.

In one embodiment, the PVA-based resin film is stretched. As the stretching method of the PVA-based resin film, any appropriate method can be employed. The orientation of the PVA resin film can be selected in any suitable direction.

A-2. Resin substrate

As the constituent material of the resin base material, any suitable material may be employed. (Meth) acrylic resin, polyamide-based resin, polycarbonate-based resin, and copolymer resins thereof, for example, an ester resin such as polyethylene terephthalate resin, a cycloolefin resin, an olefin resin such as polypropylene, . Preferably, a polyethylene terephthalate resin is used. Of these, an amorphous polyethylene terephthalate resin is preferably used. Specific examples of the amorphous polyethylene terephthalate resin include a copolymer further containing isophthalic acid as the dicarboxylic acid and a copolymer containing the cyclohexanedimethanol as the glycol.

The resin base material preferably has an elastic modulus higher than that of the PVA-based resin film (for example, a press-fit elastic modulus). By using such a resin base material, knurling can be favorably formed. Concretely, in some cases, it is difficult to form a knurling in a state where a PVA resin film alone is used, but a knurling can be formed favorably by using a laminated structure with a resin substrate.

The glass transition temperature (Tg) of the resin substrate is preferably 120 DEG C or lower, more preferably 100 DEG C or lower. This is because, when the laminate is stretched, the stretchability (particularly in water stretching) can be sufficiently secured while suppressing the crystallization of the PVA-based resin film. As a result, a polarizing film having excellent optical properties (for example, polarization degree) can be produced. On the other hand, the glass transition temperature of the resin substrate is preferably 60 占 폚 or higher. The glass transition temperature (Tg) is a value that can be obtained in accordance with JIS K 7121.

The water absorption of the resin base material is preferably 0.2% or more, and more preferably 0.3% or more. Such a resin substrate absorbs water, and water can function as a plasticizer to plasticize. As a result, the stretching stress can be largely reduced and the stretchability is excellent. On the other hand, the water absorption rate of the resin substrate is preferably 3.0% or less, more preferably 1.0% or less. By using such a resin base material, the dimensional stability of the resin base material at the time of production is significantly lowered, and problems such as deterioration of the appearance of the obtained polarizing film can be prevented. In addition, it is possible to prevent the PVA resin film from being broken at the time of underwater stretching or peeling off the PVA resin film from the resin base material. The absorption rate is a value that can be obtained in accordance with JIS K 7209.

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

The surface of the resin substrate may be subjected to a surface modification treatment (for example, corona treatment or the like), or an adhesion-facilitating layer may be formed. According to such a treatment, a laminate having excellent adhesion between the resin substrate and the PVA-based resin film can be obtained. A functional layer (for example, an antistatic layer) may be formed on the side where the PVA resin film of the resin substrate is not disposed. Blocking resistance can be imparted by forming a functional layer.

A-3. Method of making laminate

The laminate of the PVA resin film and the resin substrate can be produced by any suitable method. For example, a method of forming a PVA-based resin film on a resin substrate, and a method of laminating a resin substrate on a separately formed PVA-based resin film. When a PVA resin film is formed on a resin substrate, the coated surface is a resin substrate. In the case of forming a separate PVA resin film, the PVA resin film and the resin substrate may be laminated (using an adhesive or a pressure-sensitive adhesive) with an adhesive layer interposed therebetween, or may be laminated (practically without using an adhesive or a pressure-sensitive adhesive).

When the PVA resin film is stretched as described above, the stretching is preferably carried out on a laminate of a PVA resin film and a resin substrate. In one embodiment, a laminate of a PVA resin film and a resin substrate is stretched in the longitudinal direction by a pneumatic stretching method. The draw ratio is, for example, 1.5 times or more and 3.5 times or less. The stretching temperature is, for example, 95 ° C to 150 ° C.

The nulling can be formed by any suitable method. The lamination body 10 is nipped by the knurling roller 31 and the support roller 32 while the laminate 10 is conveyed in the longitudinal direction and the nipping roller 31 The knurl (concavo-convex structure) 13 is formed by pressing the protrusion 31a formed on the peripheral surface to the laminate 10. Though not shown, the pressing force and the peripheral surface temperature of the knurl-forming roller pair 31, 32 are appropriately adjusted. A knurling roller 31 is pressed against the resin base material 11 side to form a knurling 13 protruding from the surface of the resin base material 11. The knurling can be preferably formed by pressing the knurling roller on the resin base side as shown in the drawing, rather than pressing the knurling roller on the PVA resin film side.

Nulling can be formed at any appropriate timing. In the illustrated example, the knurling is formed on the laminate of the PVA resin film and the resin substrate. However, unlike the example shown in the drawings, the PVA resin film may be formed or laminated after the knurling is formed on the resin substrate.

A-4. etc

In one embodiment, the laminate is wound in a roll form. The winding tension is typically 300 N to 600 N. The winding may be carried out so that the PVA resin film is inward (on the core material side) or the PVA resin film is on the outer side. In the production process of the polarizing film, the laminate of the PVA resin film and the resin substrate can be stored (left) in a wound state. If the laminate (mainly resin substrate) has partial film thickness unevenness, The film is wound or wrinkled, leading to deterioration of the appearance of the resulting polarizing film. Such a problem becomes more significant as the storage period becomes longer. The laminate of the present invention can prevent the occurrence of warpage and wrinkles even when wound in roll form. As a result, a polarizing film excellent in appearance can be produced.

The frequency of occurrence of the gaps can be varied according to the thickness distribution in the width direction of the laminate (mainly resin substrate). Concretely, even if the thickness difference of the entire laminate (mainly resin substrate) is small, if thickness unevenness occurs partly, winding may occur due to winding. Therefore, in one embodiment, the height of the knurling can be set to be higher than the deviation of the thickness of the resin base material. Preferably, the height (average height) of the knurling is set to be higher than the deviation (30 mm width) of the thickness of the resin base material.

B. Polarizing film

The polarizing film is produced by performing a treatment for making the PVA-based resin film of the laminate as a polarizing film. Examples of the treatment for forming a polarizing film include dyeing treatment, stretching treatment, insolubilization treatment, crosslinking treatment, washing treatment, and drying treatment. These treatments can be appropriately selected depending on the purpose. The processing order, the timing of the processing, and the number of processing can be appropriately set. The knurling forming portion of the laminate can be cut at any appropriate timing. In one embodiment, a stretching process is performed on a laminate obtained by cutting the knurling forming portion. Any suitable method may be employed as a method of cutting the knurling forming portion. Specifically, when the knurling is formed at the end portion in the width direction of the laminate as shown in the figure, the knurled portion is cut out by cutting (slitting) the end portion in the width direction of the laminate. The cutting means may be, for example, a cutting blade such as a round blade or a dish blade, or a laser. Hereinafter, the various processes will be described.

(Dyeing treatment)

The dyeing treatment is typically performed by staining a PVA resin film with a dichroic substance. Preferably, this is carried out by adsorbing a dichroic substance on a PVA-based resin film. Examples of the adsorption method include a method in which a PVA resin film (laminate) is immersed in a dyeing solution containing a dichroic substance, a method in which the dyeing solution is applied to a PVA resin film, a method in which the dyeing solution is PVA And a method in which the resin is sprayed onto the resin film. Preferably, the laminate is immersed in the dyeing solution. This is because the dichroic material can be adsorbed well.

Examples of the dichroic material include iodine and organic dyes. These may 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 iodine aqueous solution. The blending amount of iodine is preferably 0.1 part by weight to 0.5 part by weight based on 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add iodide to an aqueous solution of iodine. 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, titanium iodide and the like. Of these, potassium iodide is preferable. The blending amount of iodide is preferably 0.02 parts by weight to 20 parts by weight, more preferably 0.1 parts by weight to 10 parts by weight, based on 100 parts by weight of water.

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

(Drawing process)

As the stretching method of the laminate, any appropriate method can be employed. Specifically, it may be a fixed-end stretching method (for example, a method using a tenter stretching machine) or a free-end stretching method (for example, a method of uniaxially stretching through a laminate between rolls different in circumferential speed). In addition, simultaneous biaxial stretching (for example, a method using a simultaneous biaxial stretching machine) or continuous biaxial stretching may be used. Stretching of the laminate may be performed in one step or in multiple steps.

The stretching treatment may be an in-water stretching method in which the laminate is immersed in a stretching bath, or a pneumatic stretching method. Preferably, the underwater stretching treatment is performed at least once, and more preferably the underwater stretching treatment and the pneumatic stretching treatment are combined. According to the underwater stretching, stretching can be performed at a temperature lower than the glass transition temperature (typically about 80 캜) of the resin substrate or the PVA-based resin film, and the PVA-based resin film can be stretched at a high magnification while suppressing its crystallization. As a result, a polarizing film having excellent optical properties (for example, polarization degree) can be produced. When the underwater stretching treatment and the pneumatic stretching treatment are combined, the pneumatic stretching treatment may be a pneumatic stretching treatment for the above-mentioned laminate.

Any suitable direction can be selected in the stretching direction of the laminate. In one embodiment, the elongated laminate is stretched in the longitudinal direction of the laminate. Specifically, the stacked body is transported in the longitudinal direction, and its transport direction (MD) is. In another embodiment, the elongated-layer laminate is stretched in the width direction. Specifically, it is a direction (TD) in which the stack is transported in the longitudinal direction and is perpendicular to the transport direction (MD).

The drawing temperature of the laminate can be set to any appropriate value depending on the forming material of the resin base material, the drawing method, and the like. In the case of adopting the pneumatic drawing method, the drawing temperature is preferably at least the glass transition temperature (Tg) of the resin base, more preferably at least the glass transition temperature (Tg) of the resin base + 10 DEG C or more, particularly preferably Tg + 15 ° C or higher. On the other hand, the stretching temperature of the laminate is preferably 170 占 폚 or less. By stretching at such a temperature, the crystallization of the PVA-based resin can be inhibited from proceeding rapidly, thereby suppressing the problem caused by the crystallization (for example, preventing the orientation of the PVA-based resin film from being stretched).

When an underwater stretching method is employed as the stretching method, the temperature of the stretching bath is preferably 40 占 폚 to 85 占 폚, and more preferably 50 占 폚 to 85 占 폚. With such a temperature, stretching can be performed at a high magnification while suppressing the dissolution of the PVA-based resin film. Specifically, as described above, the glass transition temperature (Tg) of the resin base material is preferably 60 ° C or more in relation to the formation of the PVA base resin film. In this case, if the stretching temperature is lower than 40 캜, there is a possibility that the stretching can not be performed satisfactorily even considering the plasticization of the resin substrate by water. On the other hand, as the temperature of the drawing bath becomes higher, the solubility of the PVA-based resin film becomes higher, and there is a possibility that excellent optical characteristics may not be obtained.

When an underwater stretching method is employed, it is preferable to immerse the laminate in an aqueous boric acid solution to stretch it (stretching in boric acid in water). By using an aqueous solution of boric acid as the drawing bath, it is possible to impart stiffness to the PVA type resin film against tensile force at the time of drawing and water resistance not to be dissolved in water. Specifically, boric acid can be crosslinked by hydrogen bonding with a PVA resin to produce tetrahydroxyboran anion in an aqueous solution. As a result, it is possible to produce a polarizing film having excellent optical properties, which can be stably stretched by imparting stiffness and water resistance to the PVA-based resin film.

The aqueous boric acid 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 based on 100 parts by weight of water. By setting the boric acid concentration to 1 part by weight or more, the dissolution of the PVA-based resin film 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 a boron compound such as borax, glyoxal, glutaraldehyde or the like in a solvent can also be used.

Preferably, iodide is added to the drawing bath (boric acid aqueous solution). By adding iodide, the elution of iodine adsorbed to the PVA-based 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 based on 100 parts by weight of water.

The immersing time of the laminate in the drawing bath is preferably 15 seconds to 5 minutes. The stretching ratio of the laminate by the in-water stretching method is, for example, two 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 solution of boric acid. In particular, in the case of adopting an underwater stretching method, the PVA resin film can be imparted with water resistance by performing the insolubilization treatment. The concentration of the aqueous boric acid solution is preferably 1 to 4 parts by weight based on 100 parts by weight of water. The liquid temperature of the insoluble body (aqueous solution of boric acid) is preferably 20 ° C to 40 ° C. Preferably, the insolubilization treatment is carried out before the dyeing treatment or underwater stretching treatment.

(Crosslinking treatment)

The cross-linking treatment is typically performed by immersing a PVA-based resin film in an aqueous solution of boric acid. By carrying out the crosslinking treatment, the PVA resin film can be given water resistance. The concentration of the aqueous boric acid solution is preferably 1 to 4 parts by weight based on 100 parts by weight of water. Further, in the case of carrying out the crosslinking treatment after the dyeing treatment, it is preferable to further add iodide. By adding iodide, the elution of iodine adsorbed to the PVA-based resin film can be suppressed. The blending amount of iodide is preferably 1 to 5 parts by weight based on 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 carried out before the underwater stretching treatment. In a preferred embodiment, dyeing treatment, crosslinking treatment and underwater stretching treatment are carried out in this order.

(Cleaning treatment)

The cleaning treatment is typically performed by immersing a PVA resin film in an aqueous solution of potassium iodide.

(Dry treatment)

The drying temperature in the drying treatment is preferably 30 ° C to 100 ° C.

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

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

C. polarizer

The polarizing plate of the present invention has the polarizing film. Preferably, the polarizing plate has 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 cellulose resins such as (meth) acrylic resins, diacetylcellulose and triacetylcellulose, cycloolefin resins, olefin resins such as polypropylene, polyethylene terephthalate resins and the like Ester-based resins, polyamide-based resins, polycarbonate-based resins, and copolymer resins thereof. The thickness of the protective film is preferably 10 mu m to 100 mu m.

In one embodiment, the resin base material is peeled from the polarizing film, and another film is laminated. The protective film may be laminated on the polarizing film with an adhesive layer interposed therebetween, or may be laminated (without interposing an adhesive layer). The adhesive layer is typically formed of an adhesive or a pressure-sensitive adhesive.

Example

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The method of measuring the deviation of the thickness of the resin base material and the average height of the knurling is as follows.

1. Variation of thickness of resin substrate

The thickness was measured at a pitch of 5 mm in the width direction of the resin base material by using a contact type tabletop off-line thickness measuring device (YAMABUN TOF-5R, manufactured by Yamato Buntec Co., Ltd.) The variation in thickness in width was evaluated.

2. Average height of knurling

Using a film thickness meter (manufactured by Mahr), the knurling formation portion was measured at 10 points at a pitch of 1 cm, and the average value of the obtained measurement values was calculated.

[Example 1]

(Preparation of laminate)

A corona treatment was performed on one side of a resin substrate made of amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) having a water absorption rate of 0.75% and a Tg of 75 캜, On this corona-treated side, polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetacetyl modified PVA (degree of polymerization: 1200, degree of acetacetyl modification: 4.6%, degree of saponification: 99.0 mol% Kosei Pimer Z200 ") at a ratio of 9: 1 was applied at 25 占 폚 and then dried at 60 占 폚 for 200 seconds to form a PVA-based resin film having a thickness of 10 占 퐉. The laminate thus obtained was subjected to free-end uniaxial stretching in an oven at 115 캜 in 2.0 times lengthwise direction between rolls different in the main circumferential direction (air elongation).

Thereafter, as shown in Fig. 2, knurl-forming rollers as shown in Fig. 1 are formed on both ends in the width direction of the laminate (at a position of 5 mm to 7 mm from the short side of the resin substrate) I got a sieve. The average height of the formed knurling from the resin base surface was 9.12 占 퐉.

[Example 2]

A laminate was obtained in the same manner as in Example 1 except that knurries having an average height of 6.74 mu m from the resin substrate surface were formed.

[Example 3]

A laminate was obtained in the same manner as in Example 1 except that knurling having an average height of 12.59 占 퐉 from the resin base material side was formed.

[Example 4]

A laminate was obtained in the same manner as in Example 1 except that knurling having an average height of 4.11 占 퐉 from the resin base surface was formed.

[Example 5]

A laminate was obtained in the same manner as in Example 1, except that knurling having an average height of 15.87 占 퐉 from the resin substrate surface was formed.

[Comparative Example 1]

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

(evaluation)

The laminate of each of the examples and comparative examples was evaluated for the effect of winding. The evaluation method is as follows, and the evaluation results are shown in Table 1.

(Influence by winding)

The obtained laminate was wound in a laminate roll of 3100 m to 3500 m in the longitudinal direction so that the PVA resin film was inward at a tension of 450 N, and the state of the laminate roll was observed visually immediately after the winding and 10 days after the winding.

In Example 5, no crimp was observed immediately after winding, 10 days after winding, but the vicinity of the center of the roll of the laminate was confirmed immediately after winding, and after 10 days, the folding was worse.

The polarizing film of the present invention is preferably used, for example, in an image display apparatus. Specifically, it is preferably used as a liquid crystal panel such as a liquid crystal television, a liquid crystal display, a cellular phone, a digital camera, a video camera, a portable game machine, a car navigation system, a copying machine, a printer, a fax machine, Lt; / RTI >

10:
11: resin substrate
12: Polyvinyl alcohol (PVA) based resin film
13: Knurling

Claims (11)

A polyvinyl alcohol-based resin film containing a polyvinyl alcohol-based resin,
And a resin substrate disposed on one side of the polyvinyl alcohol-based resin film,
And a knurling protruding from one surface is formed. The method according to claim 1,
Wherein the knurling is formed to protrude toward the resin base material. The method according to claim 1,
And the knurling is formed at an end portion in the width direction. The method according to claim 1,
And the formation region of the knurling extends in the longitudinal direction. The method according to claim 1,
And the knurling has a height of 5 占 퐉 to 15 占 퐉. The method according to claim 1,
And a width of 1500 mm to 2700 mm. The method according to claim 1,
Wherein the polyvinyl alcohol-based resin film is stretched. The method according to claim 1,
Wherein the resin substrate contains a polyethylene terephthalate resin. The method according to claim 1,
A laminate for producing a polarizing film, which is rolled up in a roll form. A step of cutting the knurled forming portion of the laminate according to claim 1;
And a step of stretching the laminate in this order. 11. The method of claim 10,
Wherein the stretching is an underwater stretching.

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