JP2002103410A - Method for manufacturing polymeric sheet, and polymeric sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polymeric sheet being the cover sheet of a PVA type polarizer having strong adhesive force with the PVA type polarizer and capable of developing stable polarizing characteristics even if allowed to stand for a long time under a high temperature and high humidity condition, and the excellent polymeric sheet obtained by this method. SOLUTION: The polymeric sheet is manufactured by laminating a polymer B layer peelable from a polymeric resin A layer on at least the single surface of the polymeric resin layer A by melt extrusion molding to form a laminate BA or BAB and, after at least one layer B is peeled from the laminate, surface activation treatment is applied to the layer A being in contact with the layer B and further providing a surface coating layer C on the surface activated treatment layer. Surface activation treatment is applied to the surface to be peeled of the polymeric resin layer A from which the laminated polymer layer B is peeled and the surface coating layer C is provided to the surface activation treatment surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet having substantially no molecular orientation in a sheet surface, having no defect on the surface, excellent optical isotropy, excellent heat resistance and water resistance, and moderate water vapor transmission. The present invention relates to a method for producing a polymer sheet having a high modulus and a polymer sheet.

More specifically, the present invention relates to a method for producing a polymer sheet having excellent adhesion to a hydrophilic polymer such as polyvinyl alcohol (PVA) and the polymer sheet. The present invention relates to a method for producing a polymer sheet having strong adhesion to a cover layer of a polarizer and excellent in protective function, and the polymer sheet.

[0003]

2. Description of the Related Art A polarizing film is used in the field of liquid crystal display and the like, and is generally composed of three layers in which protective layers are laminated on both surfaces of a polarizer. As the polarizer, a uniaxially oriented film in which iodine or a dye is adsorbed and dispersed in polyvinyl alcohol (PVA) is usually used.

[0004] However, this PVA-based polarizer has a weak mechanical property and is easily contracted by heat or moisture, or its polarization function is easily degraded. Therefore, it is a laminate in which protective layers are adhered to both surfaces thereof. . The protective layer has no birefringence, high light transmittance, excellent moisture resistance and heat resistance, excellent mechanical properties, smooth surface, adhesion to polarizer Is required to be good. Therefore, conventionally, cellulose triacetate (TAC) has been used as a protective layer.

[0005]

However, such a cellulose triacetate (TAC) sheet layer has an insufficient moisture-proof property, so that it cannot be used under an environment of high temperature and high humidity, for example, 80 ° C. and 90 RH%. There has been a problem that the polarizer is deteriorated in about a time and the polarization function is rapidly reduced.

[0006] Cellulose triacetate (TA)
C) has a problem that the mechanical strength is weak and a thick sheet having a thickness of 80 μm or more is generally required.
In addition, cellulose triacetate (TAC)
Since methylene chloride must be used as a solvent in the production of the sheet, there is also a problem that the solvent may adversely affect the environment and the like.

Therefore, Japanese Patent Application Laid-Open No. 4-339821 discloses
JP-A-5-212828, JP-A-10-1304
As disclosed in Japanese Patent Application Laid-Open No. 02-101, Japanese Patent Application Laid-Open No. 10-101907 and the like, it has been proposed to use a water-resistant thermoplastic norbornene-based resin instead of TAC.

[0008] However, this technique has a drawback that the polarizer cannot be prevented from deteriorating because strong adhesion to polyvinyl alcohol (PVA) cannot be obtained. Further, since the water vapor permeability is very small, Water vaporized from the polarizer containing water accumulates volatilized water at the interface between the TAC and the protective layer, causing a so-called swelling phenomenon, and cannot be used for optical applications.

That is, a protective sheet of a PVA polarizer that has excellent mechanical properties and environmental suitability without deteriorating the properties of the PVA polarizer over a long period of time has not yet existed.

The present invention provides a method for producing a polymer sheet which has solved the above-mentioned disadvantages, and a polymer sheet obtained by the method.

[0011]

The method for producing a polymer sheet according to the present invention comprises the following constitutions (1) to (10). (1) A polymer B layer which can be separated from the A resin layer is laminated on at least one surface of the polymer resin A layer by melt extrusion molding to form a laminate BA or BAB. A polymer sheet, characterized in that a surface activation treatment is performed on the surface of the layer A that has been in contact with the layer B after at least one of the layers has been peeled off, and a surface coating C layer is further provided on the surface activated treatment surface. Manufacturing method. (2) The method for producing a polymer sheet according to (1) above, wherein the surface coating C layer is a surface coating layer formed by a vapor deposition method or a surface coating layer formed by a coating material application method. (3) The method for producing a polymer sheet according to the above (1) or (2), wherein the coating material used for the surface coating C layer is a hydrophilic polymer compound. (4) The polymer sheet according to the above (3), wherein the hydrophilic polymer compound is one or more selected from a hydrophilic cellulose derivative, a hydrophilic polyester, a polyvinyl alcohol derivative and a natural polymer. Manufacturing method. (5) The method according to (1), wherein the surface activation treatment is at least one treatment selected from a plasma treatment, a corona discharge treatment, a chemical solution treatment, a surface roughening treatment, an etching treatment, and a flame treatment. ), (2), (3) or (4). (6) As a polymer compound constituting the polymer resin A layer,
The polymer according to (1), (2), (3), (4) or (5), wherein a polymer compound having a glass transition temperature of 140 ° C. or more and a light transmittance of 85% or more is used. Manufacturing method of molecular sheet. (7) As a polymer compound constituting the polymer resin A layer,
Cyclic olefin copolymer (COC), hydrogenated polystyrene,
Polycarbonate (PC), Polyarylate (PAR), Polysulfone (PSu), Polyethersulfone (PE
The method for producing a polymer sheet according to the above (6), wherein an amorphous thermoplastic polymer selected from S) and modified products thereof is used. (8) As a polymer compound constituting the polymer resin A layer,
The water vapor transmission rate is 40 to 200 (g / m ^2.
(1), (2), (3), (4), (5),
The method for producing a polymer sheet according to (6) or (7). (9) The above (1), (2), or (3), wherein the polymer sheet is used as a liquid crystal display support layer, a polarizer protective cover layer, or a touch panel support layer. ), (4), (5), (6),
The method for producing a polymer sheet according to (7) or (8). (10) The above (1), (2), and (3), wherein the polymer constituting the polymer B layer is polycarbonate (PC), polyester, polyamide, polyarylate, polyolefin, or a mixture thereof. ,
(4), (5), (6), (7), (8) or (9)
A method for producing the polymer sheet according to the above.

The polymer sheet of the present invention has the following configuration (11). (11) A surface activation treatment is performed on the surface of the polymer resin layer A from which the other polymer layer B has been peeled off,
In addition, a polymer sheet characterized in that a surface coating layer C is provided on the surface to be subjected to surface activation treatment.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a polymer sheet according to the present invention and preferred embodiments of the polymer sheet will be described.

In the method for producing a polymer sheet according to the present invention, a polymer B layer releasable from the A resin layer is laminated on at least one surface of the polymer resin A layer by melt extrusion molding to form a laminate BA or BAB. Is formed, and at least one layer of the B layer is peeled off from the laminate, and the surface of the A layer that has been in contact with the B layer is subjected to a surface activation treatment. A polymer sheet is manufactured by providing layers. In the present invention, for convenience of explanation, a laminate of a polymer resin layer A and a peelable polymer B layer on the polymer resin layer A is referred to as “BA (or AB)”, A layer in which the polymer B layer is laminated on both sides with the layer A at the center is referred to as “BAB”.

In the present invention, even if a water-resistant thermoplastic norbornene-based resin A layer is used as a PVA-based polarizer protective sheet, the adhesion to the polarizer can be improved with an aqueous adhesive without using an organic solvent. An object of the present invention is to provide a durable polarizing sheet which is excellent and has no swelling phenomenon at the bonding interface with time.

To improve the adhesion between the hydrophobic polyolefin-based norbornene-based resin A layer and the hydrophilic PVA-based resin layer, the surface of the norbornene-based resin must be in a molten state or in air. It is important to prevent the surface from easily oxidizing.

For this reason, according to the present invention, the laminate A is obtained by coextruding and laminating a polymer B layer acting as an antioxidant layer on the surface of the norbornene resin A layer by melt extrusion instead of melt extrusion of the layer A alone. BA or BAB is formed into a film, and the surface of the layer A, which has been in contact with the layer B immediately after the layer B is peeled off, is subjected to a conventionally known surface activation treatment, and the surface is coated with a layer C, Is provided. The coating material for the surface coating C layer is preferably a hydrophilic polymer compound. Further, it is needless to say that the layer B needs to be selected from a resin which can be easily separated from the layer A.

As described above, the layer B is used as a cover layer during melt film formation to prevent the layer A from being oxidized and deteriorated, and is stored and transported without peeling the cover B layer of the laminated sheet obtained by cooling. B before the time has passed from the membrane
After the layer is peeled off, preferably immediately after the layer is peeled off, a surface activation treatment is performed, and a hydrophilic resin C layer is coated thereon. That is, it is important to perform the surface activation treatment before the surface of the layer A is deteriorated by oxidation. That is, it is preferable to perform the surface activation treatment immediately after peeling, and in the present invention, the term “immediately” generally means within one day (24 hours), particularly preferably within one hour after peeling.

Therefore, even if a sheet is formed by melt-extrusion of the layer A alone or a film is formed by laminating the surface cover B layer, the sheet that has been stored and stored for a long time after the film formation or the layer B has been It is not preferable that the layer A surface is oxidatively degraded if it is stored and stored for a long time after peeling, for example, because even if the surface activation treatment is performed, a strong adhesive force with the aqueous adhesive C layer may not be obtained. Usually, the thickness of the C layer is very thin, approximately 10 μm or less, generally 0.1 to 2 μm.
Since it is about μm, it is difficult to directly measure the interlayer adhesive strength between the A layer and the C layer. Specifically, the adhesive strength between the PVA-based polarizer layer laminated on the C layer is measured. Is determined. The adhesive strength is preferably 0.8 kg /
cm or more, more preferably 1 kg / cm or more.

As the surface activation treatment, plasma treatment,
Any one or more treatments selected from corona discharge treatment, chemical treatment, surface roughening treatment, etching treatment, flame treatment, and the like can be performed. In the case of the present invention, plasma treatment, which is particularly dry treatment, corona discharge treatment Treatment, flame treatment is preferred,
The layer A is preferably treated so as to have a surface tension of 40 dynes / cm or more, more preferably 50 dynes / cm or more.

A coating C layer is laminated on the surface of the layer A which has been subjected to the surface treatment. And the like. The surface coating C layer is preferably a surface coating layer formed by a vapor deposition method or a surface coating layer formed by a coating material application method.

In the case of the present invention, it is particularly preferable that the surface coating organic coating material is a hydrophilic polymer compound, among which hydrophilic cellulose derivatives, hydrophilic polyesters, polyvinyl alcohol derivatives, natural polymers and the like. By using the selected hydrophilic polymer, not only can an environmentally friendly aqueous coating be obtained,
This is desirable in that a strong adhesive force with a VA polarizer can be obtained, and a polarizing film that is stable over time can be obtained. Typical examples include isophthalic acid having a sulfate ion or a carboxyl ion, and / or a water-soluble polyester obtained by copolymerizing a polyester with a polyhydric alcohol such as polyethylene glycol (PEG), and a water-soluble cellulose derivative such as carboxymethyl cellulose. Polyvinyl alcohol derivatives such as vinyl acetate vinyl alcohol copolymers,
Gelatin, natural polymer compounds such as gum arabic, polyvinylpyrrolidone, vinyl polymer derivatives such as polyacrylamide and the like. Particularly preferred hydrophilic polymer compounds in the present invention include water-soluble polyester polymers and water-soluble polyvinyl alcohol. It is a polymer.

The high molecular compound constituting the layer A has a glass transition temperature Tg of 140 ° C. or higher and a light transmittance of 85%.
It is preferable to use the above, for example, cyclic olefin copolymer (COC), hydrogenated polystyrene, polycarbonate (PC), polyarylate (PAR), polysulfone (PSu), polyethersulfone (PES), and the like. It is preferable to use an amorphous thermoplastic polymer selected from denatured products and the like, and the water vapor permeability of the layer A polymer compound layer is 40 to 200 (g / m ² · day · 80 μm
Sheet). 400-700
The light transmittance in nm is preferably 85% or more, more preferably 90% or more, in order to improve the visibility and visibility of the polarizing film.

Further, the glass transition temperature Tg of the resin of the layer A is preferably 140 ° C. or higher, more preferably 160 ° C. or higher. This is also because no deformation such as shrinkage or elongation or warpage occurs.

Examples of such high molecular compounds include cyclic olefin copolymer (COC), hydrogenated polystyrene, polycarbonate (PC), polyarylate (PA
R), polysulfone (PSu), polyethersulfone (PES), vinyl polymers such as acrylic polymers, and modified products thereof. Particularly in the case of the present invention, the glass transition temperature is high. A heat-resistant amorphous polymer having a Tg of preferably 140 ° C. or higher, more preferably 160 ° C. or higher is preferable, and more specifically, a polyester resin called a polyarylate having a Tg of 180 ° C. or higher, and a Tg of 160 ° C. or higher High heat-resistant polycarbonate, cyclic olefin copolymer (COC) with Tg of 140 ° C or higher, polysulfone (PS) with Tg of 170 ° C or higher
u), polyether sulfone having a Tg of 200 ° C. or higher (P
ES) Resins containing a resin as a main component are particularly preferably used.

In the case of the present invention, a cyclic olefin copolymer (COC) having a polar group, a hydrogenated polystyrene resin and the like are particularly preferable. Further, the crystalline polymer is preferably an amorphous polymer because transparency deteriorates or optical anisotropy is caused by heating.

Here, the cyclic olefin copolymer refers to a Tg having a norbornene skeleton and preferably having a Tg of 140 ° C. or more.
And a polymer obtained by hydrogenating a polymer obtained by metathesis polymerization with a tetracyclododecene derivative or an unsaturated cyclic compound copolymerizable with the tetracyclododecene, and a polymer obtained by hydrogenation. JP-A-60-168708 and JP-A-62-2524.
06, JP-A-62-252407, JP-A-63-145324, JP-A-63-264626
JP-A-2-133413, JP-A-2-133413
No. 40517, Japanese Patent Publication No. 57-8815 and the like can be used. Among them, cyclic C
Those having an appropriate polar group such as-(CH ₂ ) nCOOR in the side chain of OC, for example, those having about one in every two to five norbornene groups are most preferred, but all of the norbornene groups have polar groups. With many polar groups, such as having a group, the water vapor transmission rate is generally 200 (g / g).
m ² · day · 80 μm sheet) or more, the water absorption rate and the humidity expansion coefficient β also increase, and the properties as a protective function may be impaired.

Polyarylate (PAr) is a wholly aromatic polyester, and is typically an amorphous high Tg polymer obtained from bisphenol (A) and an aromatic dicarboxylic acid such as terephthalic acid. Which is commercially available.

Hydrogenated polystyrene is a high Tg amorphous polymer obtained by hydrogenating all benzene rings of styrene and eliminating double bonds, and is a commercially available polymer.

A typical composition of polysulfone (PSu) is a polymer compound having a sulfone group consisting of bisphenol (A) and biphenylsulfone.

Polyether sulfone (PES) is a polymer compound having an ether group and a sulfone group,
A typical composition is polyethersulfone, which is a polymer of biphenylsulfone and oxygen.
Needless to say, resins and the like selected from mixtures and modified products thereof are also included.

Further, as the protective polymer B layer on the surface,
Polycarbonate (PC), polyester, polyamide,
The polymer layer is preferably selected from polyarylate, polyolefin, and a mixture thereof.
It is important that the B resin is not compatible with the A resin and can be separated when the A and B layers are laminated. As the polymer B, two sheets of the A layer and the B layer are used. After cooling the extruded sheet obtained by laminating in a molten state, the peeling force between the layer A and the layer B is preferably 100 g / cm or less, more preferably about 1 g / cm to about 50 g / cm, and an adhesive force that can be easily peeled. However, it is not preferable that the film can be peeled off very easily because delamination occurs during sheet conveyance.

Generally, the difference between the solubility parameter of resin A and the solubility parameter of resin B is preferably 1 (cal
^1/2 / cm ^3/2 ) or more, more preferably 2 (cal ^1/2 / cm)
^3/2 ) It is preferable that the difference is not less than the above. A simple method for obtaining the solubility parameter is described in A. It is preferable to use the Small molecular intermolecular attractive constant.

Further, as the polymer resin constituting the layer B, a resin having an appropriate gas barrier property, a microcrystalline resin having an appropriate crystallization rate, and a Tg of even a completely amorphous resin can be used. It is preferable that the resin body is a blend resin body with a different resin. As a microcrystalline resin having an appropriate crystallization rate, Tg is lower than the glass transition temperature Tga of the resin A, but the crystallization rate is moderately fast, and after the resin is adhered to the cooling drum, it is removed from the drum. It is important to select a B-layer resin suitable for the casting machine, since the characteristics vary greatly depending on the drum diameter, speed, temperature, and material used. As nylon 6, polypropylene terephthalate (PPT), polybutylene terephthalate / dodecanedicarboxylate (95-60 / 5-5 mol) (PBT /
D), polycyclohexane dimethanol terephthalate (PCT) copolymer, polyethylene terephthalate / isophthalate Even if it is a completely amorphous resin, it is preferable to be a blended resin with a resin having a different Tg. A polyester resin obtained by copolymerizing a copolymer, polyhexamethylene terephthalate (PHT), bisphenol (S) or an ethylene oxide adduct of bisphenol (O);
Examples include polyolefin resins and their copolymers and blends.

It is preferable that the B resin in the present invention is a resin blended with a resin having a different Tg, even if it is a completely amorphous resin. The resin having a high Tg is responsible for the separation from the cast drum, and the resin sharing the respective roles is preferable as the B layer resin. In particular, a high Tg polycarbonate (PC) or polyarylate and a low Tg polyester or polyolefin are preferably used. A blend is preferred, and in the case of the present invention, as the surface layer polymer (B), a blend of polycarbonate (PC) and polyester is preferred in terms of castability, handleability, releasability, surface smoothness and the like.

The polycarbonate (PC) resin is a polyester of carbonic acid and glycol or divalent phenol, and has a polar group of OCOO. As a typical composition, a resin having a film-forming ability with a Tg of 120 ° C. or more is excellent as described in various literatures. Examples thereof include bis (oxyphenyl) ethane (dioxydiphenylethane) and bis (oxyphenyl) ethane. Phenyl) isobutane (dioxydiphenylisobutane) and bis (oxyphenyl) cyclohexane (dioxydiphenylcyclohexane).

The polyamide resin is a high molecular compound having an amide bond in the main chain.
Nylon 6, Nylon 66, Nylon 610, Nylon 12, Nylon 11, Nylon 7, Polymeta / p-xylylene adipamide mXD6, Polyhexamethylene terephthalamide / isophthalamide 6I / 6T, Nylon 9T and copolymers thereof, mixed It is a polyamide compound selected from a body or the like. Of course, polyethylene glycol, polypropylene glycol, polyamide ether obtained by copolymerizing a polyether compound such as polytetramethylene glycol, or a polyester amide compound obtained by copolymerizing with a polyester may be used.
Particularly excellent effects are exhibited for a multi-component copolymer which is hardly crystallized, and an amorphous polyamide resin having many or large substituents in a side chain.

Of course, various additives such as a slipping agent, a stabilizer, an antioxidant, a viscosity modifier, an antistatic agent, a colorant, and a pigment can be used in any of these polymer compound layers.

Hereinafter, a specific example of a method for producing a polymer sheet according to the present invention will be described, but the present invention is not limited thereto.

A laminate BAB obtained by laminating a thermoplastic resin A and a polymer B layer which can be peeled off from the A resin layer is uniaxially formed.
It is melted by a twin-screw, tandem extruder, etc., and each melted resin flow is laminated by a merger in front of the die called a feed block, or a resin flow widened by a manifold in the die is merged and laminated at the die land. Thus, a laminated sheet composed of three layers B / A / B is laminated, and the molten laminated sheet is solidified and cooled by a moving cooling medium such as a drum to obtain a cast sheet.

At this time, in the case of a resin which is apt to undergo oxidative decomposition or oxidation reaction, particularly an amorphous high Tg resin called COC, the resin is evacuated in advance in order to minimize oxygen during melting. Dry and deaerate completely,
It is important to perform vacuum extrusion or nitrogen displacement extrusion to prevent the oxidation reaction of the resin, and to add an antioxidant to the resin. Occasionally, the resin undergoes an oxidation reaction, and the resin is denatured to oxidation, gelation, etc., which not only results in poor adhesion with the PVA-based polarizer of the present invention, but also causes the molten resin to be extremely adhered to a metal material such as a die. This makes it easier to generate fixing streaks, which are called base streaks, and may not be used for optical purposes.

For this reason, the material in contact with the molten resin is made of TiN instead of ordinary chrome plating or nitrided steel.
It is preferable to use a ceramic material having excellent releasability such as described above, a SUS material, or the like. Also, to improve lamination accuracy in the width direction,
The die stacking method, in which the thickness of each layer can be adjusted, is superior. In particular, as in the present invention, the thickness uniformity of the central layer A layer (for example, the thickness unevenness is 5% in any direction).
The following lamination method is preferable when the following is required.

The molten resin stacked in three layers on the BAB is brought into close contact with a cooling drum and solidified by cooling. A casting method in which the center portion and the end portion of the thermoplastic resin sheet land so that they land substantially simultaneously. Is good. For this reason, it is important to select the resin of the layer B and control the temperature of the cooling drum. The glass transition temperature Tgb of the surface layer polymer B is a resin layer having a glass transition temperature (Tga−70) ° C. or higher of the layer A resin, for example, polycarbonate (PC), polyester,
Polyamide, polyarylate, polyolefin, and a resin selected from a mixture thereof, particularly in the case of the present invention,
It is preferable to use a blend of polycarbonate (PC) and polyester.
It is important that the drum is kept in close contact with the drum maintained at a temperature of not lower than (−50) ° C. and not higher than (Tgb + 20 ° C.) and cooled without slipping. This is because when the sheet slides on the drum, molecular orientation occurs, resulting in a so-called retardation of 5 nm or more, which cannot be said to be optically isotropic.

For this purpose, when the three-layer laminate BAB is brought into close contact with a cooling drum and cooled, the sheet is selected from an air knife, an air chamber, a press roll method, a liquid paraffin coating method, a static electricity applying method and the like. It is important to cast by the adhesion improving means such as the method described above.
Further, in order to bring the three-layer laminate BAB into complete contact with the cooling drum and cool it, it is preferable to further use an adhesion improving means at the sheet end. In the case of the present invention, the air chamber method is most preferred.

The casting position is preferably such that the direction in which the three-layer laminate BAB is extruded is the horizontal extrusion, and the first contact point to the cooling drum is near the top of the cooling drum. It is preferable, but not necessarily at such a casting position, that the flow direction of the so-called land in the die is substantially the same as the traveling direction of the sheet extruded under the atmosphere, or the narrow direction formed by the flowing direction and the traveling direction. By setting the angle to be within 30 degrees,
This is because a surface defect called a die streak hardly occurs over time.

The surface roughness Ry of the moving cooling medium is preferably ultra-smooth, preferably 0.4 μm or less, more preferably 0.2 μm or less for a mirror-finished roll, in order to improve the adhesion and the smoothness of the sheet. It is important. However, when it is desired to cast at a high speed, for example, the surface roughness Ry of a micro crack drum formed by applying a reverse electric field to chromium plating is 1
A rough roll of about 4 μm may be used.

The total thickness of these three-layer laminates is β
The thickness can be measured using a line, an IR absorption method, or the like. To measure the thickness of only the layer A, the thickness can be determined by optical interference or absorption such as infrared rays.

The thermoplastic resin A thus obtained according to the present invention
Since the sheet is covered with the layer B, not only can a sheet with less oxidative modification on the surface be obtained, but also it is excellent in optical isotropy with no surface defects and excellent in thickness uniformity and surface smoothness. I have.

Immediately after the layer B of the three-layer laminated sheet is peeled off, a surface activation treatment such as a plasma treatment is performed, and then an aqueous solution of a hydrophilic polymer is coated and dried. At this time, if left for a long time after the peeling of the layer B, an oxide layer that is difficult to adhere to the surface of the layer A is formed, which is not preferable.

The multilayer laminate thus obtained has a thickness of generally about 20 to 200 μm, and is a sheet having excellent light transmittance and excellent adhesion to a PVA-based polarizer. The polymer sheet can be used as a liquid crystal display support layer, a polarizer protective cover layer, or a touch panel support layer.

[0051]

[Measurement method of physical properties] Next, a method of measuring physical properties used in the description of the present invention will be described below. 1. Film thickness unevenness: Using a film thickness nest tester “KG601A” manufactured by Anritsu Corporation, the thickness of a film sampled 30 mm wide and 10 m long in the longitudinal direction of the film is continuously measured. The transport speed of the film was 3 m / min. Thickness maximum value Tmax (μ
m), the minimum value Tmin (μm) was used to determine R = Tmax−Tmin, and from R and the average thickness Tave (μm) having a length of 10 m, the thickness unevenness (%) was calculated as R / Tave × 100. 2. Thermal properties (Tm, Tg, Tmc): Sample weight 10 using a DSC-II type measuring device manufactured by PerkinElmer.
mg, the temperature was increased at a rate of 20 ° C./min under a nitrogen stream, Tg was the temperature at which the baseline began to shift, and Tcc was the exothermic peak at the further increase in temperature. The peak temperature was defined as the melting point Tm. After holding at Tm + 20 ° C. for 1 minute, the melt was cooled at a cooling rate of 20 ° C./min, and the exothermic peak temperature based on crystallization was defined as Tmc. 3. Water vapor transmission rate: According to JIS-K7129 B method
It was measured at 40 ° C. and 90 RH%. Unit is g / m ² · 24
Time and sheet.

PERMATRAN-WI manufactured by MOCON
A was used. 4. Light transmittance: The total light transmittance of visible light in the wavelength range of 300 to 700 nm was measured using a spectrophotometer U-3410 (Hitachi, Ltd.), and the light transmittance at 550 nm was adopted. 5. Retardation: The sample was set under a polarizing microscope, the sample was rotated 45 ° from the extinction position, and the value at which the polarization interference color was eliminated by a compensator was defined as the retardation. The unit is nm. 6. Adhesive force (kg / cm): A value obtained by dividing the strength (kg) required for peeling obtained by a T-peel peel test according to JIS Z0237 by the width of a test piece.

[0053]

EXAMPLES Examples and comparative examples are shown below to make the present invention easier to understand.

Example 1 As the organic polymer compound A, a cyclic olefin copolymer COC which is a norbornene resin having a polar group half of the molecule
("Zeonor" manufactured by Zeon Corporation, Tg: 165 ° C, 50
Wt%, JSR “ARTON”, Tg175 ° C 50
The raw material A was vacuum-dried to remove moisture and dissolved oxygen using a conventional method, and then supplied to a 150 mm vacuum extruder in which the space between the raw material hopper and the extruder was replaced with nitrogen. And melted. On the other hand, as the resin B to be peeled off from the resin A, a polyethylene terephthalate (PET) resin (intrinsic viscosity: 0.65, Tg: 70 ° C.)
30% by weight and polycarbonate (PC) resin (Tg: 1
(50 ° C.) 70% by weight of a mixed raw material (apparent Tg is 13
0 ° C.), according to a conventional method, vacuum-drying the mixed raw material B, supplying the mixed raw material B to a 65 mm melt extruder, melting the mixed raw material B at 280 ° C., and passing each through a filter for removing foreign substances of 15 μm or more. After laminating in the die so as to have three layers of B / A / B, a 1200 mm wide crow die-shaped T die die (set so that the resin flow direction is horizontal)
Extruded onto the top of a cast drum at a distance of 50 mm from the LD. At this time, the narrow angle between the resin flow direction and the molten resin sheet at the die land was 0 degree.
In order to improve the adhesion between the drum and the resin sheet, a mirror chrome plating drum (drum diameter: 1800) maintained at a high temperature of 140 ° C. using an air chamber from the ground point
mm, maximum surface roughness Rt: 0.1 μm, 30 m /
The mixture was adhered and cooled and solidified at a speed of min. At this time, air knives were used at both ends to improve the adhesion.

The thus obtained three-layer cast film had a total thickness of 60 μm, each layer having a thickness of 5 μm / 50 μm / 5 μm. The thickness unevenness of the entire layer and the A layer was 3% in both the longitudinal and width directions. It is as small as the following, and even if the frequency analysis of the thickness unevenness of the A layer is performed, there is no thickness unevenness caused by the landing vibration of 3 to 10 Hz, the thickness uniformity is excellent, and the flatness is also excellent. Excellent, no surface defects such as craters and base lines,
A perfectly isotropic amorphous 40 with a retardation of 3 nm
The sheet was a 0 μm sheet, had no edge variation, had a light transmittance of 90% or more in the range of 400 to 700 nm, was transparent and completely amorphous, and had excellent optical isotropy. .

The layer B on one side is peeled off from the three-layer film,
A plasma discharge treatment was performed on the peeled A resin film surface within 10 minutes, and a coating treatment with an aqueous solution comprising a water-soluble polyester was performed. As a result, the coat thickness after drying was 2 μm.

At this time, as the water-soluble polyester used, a polyester composed of 90 mol% of terephthalic acid, 10 mol% of sodium isophthalate sulfonic acid, 90 mol% of ethylene glycol and 10 mol% of polyethylene glycol was used.

The properties of the layer A thus obtained are as follows: Tg17
1 ° C., retardation 1 nm, 30 to 80 at 30 ° C.
The humidity expansion coefficient of RH% was 7 ppm /%, the center line average surface roughness Ra was 2 nm, the Young's modulus was 200 kg / mm ² , and the light transmittance was 92%.

The surface coat A layer thus obtained and the PVA-based polarizer film 80 μm were adhered using water in which gum arabic was dissolved. The adhesion between the layers is 1.2 kg /
cm. For this reason, even when the polarizer was left under high humidity for a long time, the polarization characteristics and appearance of the polarizer did not change.

The excellent polarizing film thus obtained is
It was useful for LCD plastic substrates such as mobile phone display screens and personal computer display screens, especially for applications that are strict in optical characteristics such as large-screen color display. Comparative Example 1 A 50-μm-thick A-layer sheet alone was formed in exactly the same manner as in Example 1, except that the surface layer B resin used in Example 1 was not laminated and a film was formed as a single layer of only resin A. did.

As a result, after the obtained sheet was subjected to the plasma discharge treatment, the sheet was coated with an aqueous solution comprising a water-soluble polyester, and the sheet was bonded to a PVA-based polarizer film 80 μm using water in which gum arabic was dissolved. The adhesive strength between the layers is as low as 0.3 kg / cm, which is 10 kg in an environment of 80 ° C. and 90 RH%.
When left under a high temperature and high humidity of 0 hours for a long time, the polarization characteristics of the polarizer rapidly deteriorated, and not only was the polarizing film unusable, but also the flatness was deteriorated and the appearance was deteriorated.

[0062]

According to the method for producing a polymer sheet of the present invention, there is no in-plane molecular orientation, no defects on the surface, excellent optical isotropy, excellent heat resistance and water resistance, and moderate water vapor. It is a polymer sheet having a transmittance, and can be used to produce a polymer sheet having excellent adhesion to a hydrophilic polymer such as polyvinyl alcohol (PVA). In particular, it was possible to produce a polymer sheet having strong adhesiveness to a cover layer of a polarizer mainly composed of a polyvinyl alcohol-based polymer, which had not existed conventionally, and having excellent optical properties and protective functions. It is a thing.

The multilayer laminate obtained as a polymer sheet in the present invention has a thickness of generally about 20 to 200 μm, is excellent in light transmittance, and is excellent in adhesiveness to a PVA-based polarizer. The polymer sheet can be favorably used as a liquid crystal display support layer, a polarizer protective cover layer, or a touch panel support layer.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 1/10 G02B 5/30 4F207 5/30 C08L 101: 00 // C08L 101: 00 G02B 1/10 Z F term (for reference) 2H049 BA02 BB27 BB28 BB29 BB34 BB43 BB54 BC22 2K009 BB13 BB14 BB24 CC34 DD02 DD03 DD11 DD12 DD17 EE00 EE04 4F006 AA15 AA35 AA36 AA40 AB02 AB03 AB20 BA01 DA04 4F073 AA01 BA01 BA01 GA01 AJ01C AJ06A AJ06C AK01A AK01B AK01C AK02B AK12B AK21A AK21C AK41A AK41C AK42 AK43B AK45B AK55B AL01B BA03 BA06 BA10A BA10C EH20 EH46 EH66 EJ55 EJ61 EJ64B GB41 JA05B JA12B JB05A JB05C JD04 JD04B JJ03 JK15 JL11 JN01 JN01B YY00B 4F207 AA12 AA24 AA28 AE10 AG01 AH73 AR13 KA01 KB22 KM26 KW50

Claims (12)

[Claims] 1. A polymer resin A layer on at least one surface thereof,
A laminate B or BAB was formed by laminating a peelable polymer B layer with the resin layer by melt extrusion molding, and was in contact with the B layer after peeling off at least one of the B layers from the laminate. A method for producing a polymer sheet, comprising performing a surface activation treatment on the surface of the layer A, and further providing a surface coating C layer on the surface activation treatment surface. 2. The method for producing a polymer sheet according to claim 1, wherein the surface coating C layer is a surface coating layer formed by a vapor deposition method or a surface coating layer formed by a coating material application method. 3. The method for producing a polymer sheet according to claim 1, wherein the coating material used for the surface coating C layer is a hydrophilic polymer compound. 4. The polymer according to claim 3, wherein the hydrophilic polymer compound is one or more selected from hydrophilic cellulose derivatives, hydrophilic polyesters, polyvinyl alcohol derivatives and natural polymers. Sheet manufacturing method. 5. The method according to claim 1, wherein the surface activation treatment is at least one treatment selected from the group consisting of plasma treatment, corona discharge treatment, chemical treatment, surface roughening treatment, etching treatment, and flame treatment. Item 5. The method for producing a polymer sheet according to item 1, 2, 3, or 4. 6. The polymer compound constituting the polymer resin A layer has a glass transition temperature of 140 ° C. or higher and a light transmittance of 8%.
The method for producing a polymer sheet according to claim 1, wherein a polymer compound having a content of 5% or more is used. 7. The polymer compound constituting the polymer resin A layer includes cyclic olefin copolymer (COC), hydrogenated polystyrene, polycarbonate (PC), polyarylate (PA)
7. The method for producing a polymer sheet according to claim 6, wherein an amorphous thermoplastic polymer selected from R), polysulfone (PSu), polyethersulfone (PES), and modified products thereof is used. . 8. The polymer constituting the polymer resin A layer has a water vapor transmission rate of 40 to 200 (g / m ² · day ·
The method for producing a polymer sheet according to claim 1, 2, 3, 4, 5, 6, or 7, wherein a polymer compound (80 µm sheet) is used. 9. The method according to claim 1, wherein the polymer sheet is used as a liquid crystal display support layer, a polarizer protective cover layer, or a touch panel support layer.
The method for producing a polymer sheet according to 3, 4, 5, 6, 7, or 8. 10. The method according to claim 1, wherein the polymer constituting the polymer B layer is polycarbonate (PC), polyester, polyamide, polyarylate, polyolefin, or a mixture thereof. 5,
10. The method for producing a polymer sheet according to 6, 8, or 9. 11. A surface activation treatment is performed on the surface of the polymer resin layer A from which the other polymer layer B has been peeled off, and a surface coating layer C is formed on the surface activation treatment surface. A polymer sheet characterized by comprising: 12. The polymer sheet according to claim 11, wherein the polymer sheet is used as a liquid crystal display support layer, a polarizer protective cover layer, or a touch panel support layer.