JP4910271B2 - Stretched laminate - Google Patents

Description

  The present invention relates to a stretched laminate comprising an alicyclic polyolefin resin excellent in transparency and slipperiness, and further to a polarizing plate and a liquid crystal display device having the stretched laminate having excellent visibility and durability.

In a liquid crystal display device, a retardation film is widely used to compensate for a retardation due to birefringence of a liquid crystal cell. Various retardation films have been proposed so far, and stretched films obtained by orienting transparent resins by stretching have been widely used. Examples of the stretched film include a film made of a polycarbonate resin having excellent heat resistance and the like, and in particular, a film made of an alicyclic polyolefin resin having excellent heat resistance, low hygroscopicity, and a small photoelastic constant has recently attracted attention. I'm bathing.
By the way, since the alicyclic polyolefin resin film is not sufficiently slippery, the handling may be hindered. For example, in the final stage of production, the film is often wound up by a winder to make a roll film. However, if the film is not sufficiently slippery, the film may be wrinkled or broken and wound up. In some cases, the quality of the film deteriorated significantly. Therefore, in practice, after the film was formed, a method of performing a winding operation after further laminating a film having excellent slipperiness on the film was performed, but the process became complicated and led to high costs. .
In order to solve this problem, a transparent film having improved slidability by blending crosslinked polymer particles with a cyclic polyolefin resin, which is a kind of alicyclic polyolefin film, is disclosed (Cited document 1). Here, in practice, a technique of adding crosslinked polymer particles to the resin is used. However, the cyclic polyolefin resin film here has a drawback in that the transparency is lowered when it is stretched. Therefore, further improvement has been demanded in order to apply the cyclic polyolefin resin film to a retardation film.

Japanese Patent Laid-Open No. 7-196885

  Accordingly, an object of the present invention is to provide a stretched laminate comprising an alicyclic polyolefin resin having excellent transparency and excellent slipperiness so that wrinkles and creases do not occur even when wound up, and further, a visibility having the stretched laminate. And a polarizing plate and a liquid crystal display device excellent in durability.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention include a stretched film obtained by stretching a film made of a transparent alicyclic polyolefin resin containing particles having a specific range of refractive index and average particle size. The inventors have found that the above object can be achieved by laminating layers having a refractive index in a specific range, and have completed the present invention.

Thus, according to the present invention,
(1) A polarizing plate having a stretched laminate formed by laminating a stretched film layer (A) formed by stretching a film made of a transparent resin and a layer made of a resin (B) containing particles (C). There,
Layer (A) is made of alicyclic polyolefin resin,
The resin (B) includes a polyvinyl alcohol polymer or an ethylene-vinyl alcohol copolymer,
The volume ratio of particles (C) to resin (B) is 1% to 30%,
The average particle size of the particles (C) is 0.01 to 0.10 μm,
The refractive indexes of the resin (B) and the particles (C) are both 1.50 to 1.55 ,
Polarizer haze and having an extended elongation laminate Ru der 0.2,
(2) The polarizing plate according to (1), wherein the surface resistance of the layer made of the resin (B) is 1 × 10 ¹² Ω / □ or less,
(3) The polarizing plate according to (1) or (2), wherein the particles (C) are titanium oxide-silicon oxide based metal oxides,
(4) The polarizing plate according to any one of (1) to (3), wherein the ethylene-vinyl alcohol copolymer contains 60 mol% or more of vinyl alcohol units ,
(5 ) A liquid crystal display device having the polarizing plate according to any one of (1) to (4),
Is to provide.

  The stretched laminate of the present invention has good slipperiness, excellent transparency and durability, and therefore, as a retardation plate that has excellent handling properties and good optical properties over a long period of time, a liquid crystal display device, organic EL Widely applicable to display devices.

  The stretched laminate of the present invention has a stretched film layer (A) formed by stretching a film composed of a transparent alicyclic polyolefin resin, and a layer composed of a resin (B) containing particles (C).

  The alicyclic polyolefin resin used in the present invention is a polyolefin resin having an alicyclic structure in the main chain and / or side chain, and contains an alicyclic structure in the main chain from the viewpoint of mechanical strength, heat resistance and the like. Polyolefin resins are preferred.

  Examples of alicyclic structures include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene) structures. From the viewpoint of mechanical strength and heat resistance, cycloalkane structures and cycloalkane structures can be used. Alkene structures are preferred, with cycloalkane structures being most preferred. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the alicyclic polyolefin resin used in the present invention may be appropriately selected according to the purpose of use, preferably 55% by weight or more, more preferably It is 70% by weight or more, particularly preferably 90% by weight or more. When the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is in this range, it is preferable from the viewpoint of the transparency and heat resistance of the optical laminate.

  Examples of the alicyclic polyolefin resin include a norbornene resin, a monocyclic olefin resin, a cyclic conjugated diene resin, a vinyl alicyclic hydrocarbon resin, and hydrides thereof. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening polymer of a monomer having a norbornene structure and another monomer, a hydride thereof, or a norbornene structure. Examples thereof include addition polymers of monomers, addition polymers of monomers having a norbornene structure and other monomers, and hydrides thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Can be used.

Examples of monomers having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene. (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.
Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene; Derivatives thereof; and the like.
A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, And cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.
An addition polymer of a monomer having a norbornene structure and an addition copolymer of a monomer having a norbornene structure with another monomer copolymerizable with a monomer having a norbornene structure are prepared in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  A hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, a hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and another monomer capable of ring-opening copolymerization thereof, Hydrogenated products of addition polymers of monomers having a norbornene structure and hydrogenated products of addition polymers of monomers having a norbornene structure and other monomers copolymerizable therewith are not A known hydrogenation catalyst containing a transition metal such as nickel or palladium is added to the combined solution, and the carbon-carbon unsaturated bond is preferably hydrogenated by 90% or more.

Among norbornene-based resins, as repeating units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by weight or more based on the entire repeating units of the norbornene-based resin, and the content ratio of X and the content ratio of Y Is preferably 100: 0 to 40:60 by weight ratio of X: Y. By using such a resin, it is possible to obtain an optical film that has no dimensional change in the long term and is excellent in stability of optical characteristics.

  The molecular weight of the alicyclic polyolefin resin used in the present invention is appropriately selected according to the purpose of use, but it is determined by gel permeation chromatography using cyclohexane (toluene when the polymer resin does not dissolve) as a solvent. The weight average molecular weight (Mw) in terms of isoprene or polystyrene is usually 10,000 to 100,000, preferably 15,000 to 80,000, more preferably 20,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The glass transition temperature of the alicyclic polyolefin resin may be appropriately selected according to the purpose of use, but is preferably 80 ° C. or higher, more preferably in the range of 100 to 250 ° C. A film containing a norbornene-based resin having a glass transition temperature in such a range is excellent in durability without being deformed or stressed when used at a high temperature.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic polyolefin resin is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 4.0, more preferably. Is in the range of 1.2 to 3.5.

Alicyclic polyolefin resin used in the present invention preferably has an absolute value of the photoelastic coefficient is ¹⁰ × 10 -12 ^{Pa -1} or less, more preferably 7 × ¹⁰ -12 ^{Pa -1} or less, 4 It is particularly preferable that it is 10 ⁻¹² Pa ⁻¹ or less. The photoelastic coefficient C is expressed as follows: birefringence is Δn and stress is σ.
C = Δn / σ
It is a value represented by If the photoelastic coefficient of the alicyclic polyolefin resin exceeds 10 × 10 ⁻¹² Pa ⁻¹ , the variation in in-plane retardation of the optical laminate may be increased.

  In the present invention, the alicyclic polyolefin resin preferably contains substantially no particles. Here, “substantially free of particles” means that even when particles are added to a film made of an alicyclic polyolefin resin, the increase in haze from the non-added state is up to a certain amount within a range of 0.05 or less. Means acceptable. In particular, since alicyclic polyolefin resin lacks affinity with many organic particles and inorganic particles, when an alicyclic polyolefin resin film to which particles exceeding the above range are added is stretched, voids are easily generated. As a result, a significant increase in haze may occur.

  In addition to the particles, known additives such as antioxidants, heat stabilizers, light stabilizers, and UV absorbers are added to the alicyclic polyolefin resin used in the present invention as long as the effects of the invention are not impaired. Also good.

There is no restriction | limiting in particular as a method of manufacturing the film which consists of alicyclic polyolefin resin used for this invention, For example, conventionally well-known methods, such as a solution casting method, the injection molding method, and a melt extrusion method, are mentioned. Among these, the melt extrusion method that does not use a solvent is preferable from the viewpoints of being able to efficiently reduce the amount of residual volatile components in the layer (A), and being excellent in terms of the global environment and working environment, and manufacturing efficiency.
Examples of the melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

The (A) layer has a total light transmittance of 80% or more at a thickness of 1 mm. More preferably, the total light transmittance is 90% or more.
The (A) layer has a haze of 1 mm or less of 0.3 or less. Preferably, haze is 0.2 or less. If the haze exceeds 0.3, the transparency of the laminate is lowered, and there is a possibility that it cannot be applied to a retardation film.

  (A) In-plane average retardation; Re and thickness direction average retardation; Rth value varies depending on the display design, but generally 40 to 120 nm for Re and about 100 to 300 nm for Rth The range of is preferable.

The average thickness of the layer (A) is preferably 40 to 120 μm, more preferably 40 to 100 μm, and particularly preferably 40 to 80 μm from the viewpoint of mechanical strength and the like.
The thickness variation of the layer (A) is preferably within ± 3% of the thickness over the longitudinal direction and the width direction. (A) By making the thickness variation of the layer within the above range, the variation in optical characteristics such as Re of the laminate of the present invention can be reduced.

The content of the residual volatile component in the layer (A) is not particularly limited, but is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. If the content of the residual volatile component exceeds 0.1% by weight, the optical properties of the laminate may change over time. By adjusting the content of the volatile component to the above range, the dimensional stability can be improved, the change with time of Re and Rth of the layer (A) can be reduced, and further the polarizing plate having the laminate of the present invention. And deterioration of the liquid crystal display device can be suppressed, and the display on the display can be kept stable and good for a long time.
The volatile component is a substance having a molecular weight of 200 or less contained in a trace amount in the layer (A), and examples thereof include residual monomers and solvents. The content of the volatile component can be quantified by analyzing the (A) layer by gas chromatography as the sum of substances having a molecular weight of 200 or less contained in the (A) layer.

The saturated water absorption of the layer (A) is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, and particularly preferably 0.01% by weight or less. When the saturated water absorption is in the above range, the change with time of Re and Rth in the layer (A) can be reduced, and further, the deterioration of the polarizing plate and the liquid crystal display device having the laminate of the present invention can be suppressed. In particular, the display can be kept stable and good.
The saturated water absorption is a value expressed as a percentage of the mass of the test piece before the immersion of the increased mass by immersing the test piece of the layer (A) in water at a constant temperature for a fixed time. Usually, it is measured by immersing in 23 ° C. water for 24 hours.
The saturated water absorption rate in the layer (A) can be adjusted to the above value by, for example, reducing the amount of polar groups in the thermoplastic norbornene resin, but is preferably a resin having no polar groups. Is desired.

  (A) There is no restriction | limiting in particular as a method of manufacturing a layer, A conventionally well-known method can be applied. Specifically, a uniaxial stretching method such as a method of uniaxially stretching in the longitudinal direction using a difference in peripheral speed between rolls, a method of uniaxially stretching in the lateral direction using a tenter; Simultaneously biaxial stretching method that stretches in the transverse direction according to the spread angle of the guide rail at the same time as stretching in the longitudinal direction, or after stretching in the longitudinal direction by utilizing the difference in peripheral speed between the rolls, both ends thereof are clipped and tenter And a biaxial stretching method such as a sequential biaxial stretching method in which stretching is performed in the transverse direction.

Examples of the method of stretching in the machine direction include an IR heating method and a float method between rolls, and the latter is preferable for obtaining optical uniformity required for the use of the film of the present invention. There are no particular restrictions on the stretching conditions, but the stretching temperature may be adjusted in order to obtain desired optical characteristics in the range of Tg to Tg + 20 ° C. and the stretching ratio in the range of 1.1 to 3.0 times.
An example of a method of stretching in the transverse direction is a tenter method. In this case as well, there are no particular restrictions on the stretching conditions, but the stretching temperature is adjusted in the range of Tg to Tg + 20 ° C., and the stretching ratio is adjusted in the range of 1.3 to 3.0 times to obtain desired optical characteristics. That's fine.

  (A) The surface of the layer can be subjected to surface treatment as necessary. Examples of the surface treatment include glow discharge treatment, corona discharge treatment, ultraviolet treatment, and flame treatment. The surface treatment may be performed before or after the layer made of the resin (B) is stacked. (A) By surface-treating the layer surface, for example, the adhesiveness with the layer made of the resin (B) can be improved.

  The resin (B) used in the present invention is not particularly limited, and a known thermoplastic resin, thermosetting resin, radiation curable resin, reactive resin, and a mixture thereof can be used. Containing polar groups such as polyvinyl polymers, derivatives thereof, cellulose derivatives such as ethylene-vinyl alcohol copolymer, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, starches such as oxidized starch, etherified starch and dextrin, polyvinylpyrrolidone and sulfoisophthalic acid Copolymer polyesters, vinyl polymers such as polyhydroxyethyl methacrylate or copolymers thereof, acrylic polymers, urethane polymers, ether polymers, or carboxyl groups, amino groups, and methylol groups of these polymers. Sensuality Modified polymer and the like are used.

  Among these, polyvinyl alcohol polymers and ethylene-vinyl alcohol copolymers are more preferable, and polyvinyl alcohol or ethylene-vinyl alcohol copolymers having a saponification degree of 80 mol% or more are particularly preferably used.

  The ethylene-vinyl alcohol polymer preferably contains 60 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more of vinyl alcohol units, and preferably 40 mol% of ethylene units. Hereinafter, an ethylene-vinyl alcohol copolymer copolymerized so as to have a content of 20 mol% or less, particularly preferably 10 mol% or less is preferably used.

  These polyvinyl alcohol polymers or ethylene-vinyl alcohol copolymers may of course be used alone, but can be used in combination with other resin compounds that can be mixed as long as the object of the present invention is not impaired. As such a resin, for example, an acrylic resin made of polyacrylic acid or its ester, a polyester resin, a polyurethane resin, a polyamide resin, an epoxy resin, a melamine resin, or the like can be used. Moreover, in order to make the layer which consists of (B) strong, addition of a crosslinking agent etc. is preferable.

  The refractive index of the resin (B) used in the present invention is 1.45 to 1.60. It is preferably 1.47 to 1.57, more preferably 1.50 to 1.55, and particularly preferably 1.52 to 1.55. Outside this range, the transparency of the stretched laminate of the present invention is reduced.

  An antistatic agent is preferably added to the layer made of the resin (B) used in the present invention in order to suppress sticking in the process and generation of sparks due to static electricity. There is no restriction | limiting about this antistatic agent, Any type of nonionic, anionic, cationic, and amphoteric types may be used, and these may be used together. Moreover, although it may be a low molecular weight type or a high molecular weight type, a sodium alkyl sulfonate type antistatic agent can be mentioned as a suitable example. By adding an antistatic agent to the resin (B), the surface resistance value of the stretched laminate of the present invention can be lowered, and the handleability of the laminate is also improved.

The layer made of the resin (B) preferably has a surface resistance value of 1 × 10 ¹² Ω / □ or less from the viewpoint of excellent handling properties and production efficiency. When the surface resistance value exceeds 1 × 10 ¹² Ω / □, sparks due to static electricity or sticking of the laminate may occur in the film-forming process of the laminate.

  The particles (C) in the present invention are not particularly limited and may be inorganic particles or organic particles, but metal oxide fine particles can be preferably used. For example, titanium oxide, zirconium oxide, zinc oxide, copper oxide, aluminum oxide, cerium oxide, yttrium oxide, silicon oxide, tin oxide, iron oxide, magnesium oxide, and manganese oxide can be exemplified. Of these, titanium oxide-silicon oxide-based metal oxides are preferable from the viewpoint of easy adjustment of the refractive index. These particles can be produced, for example, using the technique described in JP-A-7-2520.

  The average particle diameter of the particles (C) used in the present invention is 0.01 to 0.10 μm. Preferably it is 0.02-0.08 micrometer, More preferably, it is 0.03-0.06 micrometer. When the average particle size exceeds 0.10 μm, the decrease in transparency becomes remarkable, and when the average particle size is less than 0.01 μm, it cannot contribute to improvement of the winding property.

  The refractive index of the particles (C) is 1.45 to 1.60. It is preferably 1.47 to 1.57, more preferably 1.50 to 1.55, and particularly preferably 1.52 to 1.55. Outside this range, the transparency of the stretched laminate of the present invention is reduced.

  The mixing ratio of the resin (B) and the particles (C) used in the present invention is such that the volume ratio of (C) to (B) is 1 to 30%, preferably 1 to 20%, more preferably 1 to 15%. It is. When the volume ratio is less than 1%, the winding property of the stretched laminate is not affected at all. On the other hand, when the volume ratio exceeds 30%, white powder is generated on the surface of the stretched laminate due to the dropping of the particles, resulting in scratches, or the strength of the layer made of the resin (B) containing the particles (C) decreases. There is a risk of

  The method for laminating the (A) layer and the layer made of the resin (B) is not particularly limited, but a solution of the resin (B) containing the particles (C) and dissolved in a known solvent is added to the (A) layer. A method of applying and laminating is preferable. The method of applying the resin (B) solution is not particularly limited. From the viewpoint of forming a thin film layer at high speed, the gravure coating method, reverse coating method, spray coating method, kiss coating method, comma coating method, die coating method. A knife coating method, an air knife coating method or a metal ring bar coating method can be preferably used. The step of applying the solution of the resin (B) may be provided during the film forming step of the (A) layer or after the film forming step, but is preferably provided during the film forming step from the viewpoint of manufacturing efficiency. . In particular, in the step of forming the layer (A) by stretching in the lateral direction by a tenter method, it is preferable to apply the layer immediately before the stretching operation.

  The friction coefficient between the layer (A) of the stretched laminate of the present invention and the layer made of the resin (B) is preferably 0.8 or less from the viewpoint of improving the handleability of the laminate. When the coefficient of friction exceeds 0.8, when the laminate is wound into a roll, the laminate may be wrinkled or broken and may not be neatly wound.

  The stretched laminate of the present invention has a haze at a thickness of 1 mm of 0.3 or less. Preferably, haze is 0.2 or less. If the haze exceeds 0.3, the transparency of the stretched film is lowered, and it cannot be suitably used for a retardation film or the like.

  In the stretched laminate of the present invention, Re variation is within 10 nm, preferably within 5 nm, and more preferably within 2 nm. By setting the Re variation within the above range, it is possible to improve the display quality when used as a retardation film for a liquid crystal display device. Here, the variation in Re is the maximum value of Re when the light incident angle is 0 ° (when incident light and the surface of the laminate of the present invention are orthogonal to each other) and Re is measured in the width direction of the laminate. It is the difference from the minimum value.

  The stretched laminate of the present invention is preferably long. The long shape means one having a length of at least about 5 times or more with respect to the width direction of the film or laminate, preferably 10 times or more, and specifically in a roll shape. It has a length that is wound and stored or transported.

  The polarizing plate of the present invention is formed by laminating the stretched laminate of the present invention on at least one surface of a polarizing film. For the polarizing film, a film made of a suitable vinyl alcohol polymer such as polypinyl alcohol or partially formalized polyvinyl alcohol, etc., dyeing treatment with a dichroic substance such as iodine or dichroic dye, stretching Appropriate treatments such as treatment and cross-linking treatment can be performed in an appropriate order and manner, and appropriate materials that transmit linearly polarized light when natural light is incident can be used. In particular, those excellent in light transmittance and degree of polarization are preferable. The thickness of the polarizing film is generally 5 to 80 μm, but is not limited thereto.

  As a lamination | stacking form, the extending | stretching laminated body of this invention may be laminated | stacked on both surfaces of a polarizing film, may be laminated | stacked on one side, and there is no limitation in particular in the number of lamination | stacking, You may laminate | stack two or more sheets. In particular, from the viewpoint of improving the handleability of the polarizing plate of the present invention, it is preferable to laminate the layered product with the layer (A) side facing the polarizing film. Moreover, as a lamination | stacking method, although it is not an essential method, it can laminate | stack using an adhesive agent. Another member can be interposed between the stretched laminate and the polarizing film as long as the characteristics of the present invention are not impaired.

  For the purpose of protecting the polarizing film, a protective film may be bonded to one side or both sides of the polarizing film via an appropriate adhesive layer. An appropriate transparent film can be used as the protective film. Among them, a film having a resin excellent in transparency, mechanical strength, thermal stability, moisture shielding property, etc. is preferably used. Examples of the resin include an acetate polymer such as triacetyl cellulose, a polymer having an alicyclic structure, a polyolefin polymer, a polycarbonate polymer, a polyester polymer such as polyethylene terephthalate, a polyvinyl chloride polymer, and a polystyrene polymer. Polyacrylonitrile polymer, polysulfone polymer, polyether sulfone polymer, polyamide polymer, polyimide polymer, acrylic polymer and the like.

  When the stretched laminate of the present invention is in contact with the polarizing film, the stretched laminate can also be used as a protective film for the polarizing film. By using the stretched laminate as a protective film for the polarizing film, the thickness of the liquid crystal display device can be reduced by omitting one protective film, and the durability of the polarizing film can be improved.

  Since the stretched laminate of the present invention can be easily manufactured and highly compensated for birefringence, it can be used alone or in combination with other members as a retardation plate or a viewing angle compensation film. The present invention can be widely applied to EL display devices, plasma display devices, FED (field emission) display devices, SED (surface electric field) display devices and the like. Examples of the liquid crystal display device include an in-plane switching (IPS) mode, a vertical alignment (VA) mode, a multi-domain vertical alignment (MVA) mode, a continuous spin wheel alignment (CPA) mode, a hybrid alignment nematic (HAN) mode, Examples thereof include a twisted nematic (TN) mode, a super twisted nematic (STN) mode, and an optically compensated bend (OCB) mode.

  In the liquid crystal display device of the present invention, when forming the liquid crystal display device, for example, a prism array sheet, a lens array sheet, a light diffusing plate, a backlight, a brightness enhancement film, etc. The above can be arranged. Examples of the backlight include a cold cathode tube, a mercury flat lamp, a light emitting diode, and an EL.

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.
Parts and% are based on weight unless otherwise specified.
Evaluation in this example is performed by the following method.
(1) Thickness After embedding the stretched laminate in an epoxy resin, slice it to a thickness of 0.05 μm using a microtome (RUB-2100) manufactured by Daiwa Koki Co., Ltd., and observe the cross section under a microscope. Measure the thickness.
(2) Haze Using a Nippon Denshoku Industries Co., Ltd. haze meter (NDH-2000), three points were arbitrarily measured over the entire surface of the stretched laminate, and the average value of the three points was taken as the measured value. To do.
(3) Refractive index of resin (B) After apply | coating the solution of resin (B) used for this invention on a glass plate and drying a solvent at 90 degreeC, a resin (B) layer is peeled from a glass plate. , (B) The refractive index of the layer is measured with an Abbe refractometer (D line 589 nm).
(4) Refractive Index of Particle (C) After drying the particle (C) used in the present invention at 90 ° C., (C) is suspended in various liquids at 25 ° C. having different refractive indexes. The refractive index of the liquid that appears transparent is measured with an Abbe refractometer (D line 589 nm).
(5) Average particle diameter of particles (C) Using a sputtering apparatus (JPC-1000 type) manufactured by JEOL Ltd., ion etching treatment is performed on the surface of the layer made of resin (B) of the stretched laminate under the following conditions. Apply. The condition is that a sample is placed in a bell jar, the degree of vacuum is increased to about 1 × 10 ⁻³ Torr, and ion etching is performed at a voltage of 0.25 kv and a current of 12.5 mA for about 10 minutes. Further, the surface was subjected to gold sputtering with the same apparatus, and observed with a scanning electron microscope at a magnification of 10,000 to 30,000 times. Subsequently, the image analysis apparatus (Luzex 500) manufactured by Japan Regulator Co., Ltd. was used. The major axis Dli, minor axis Dsi, and area equivalent circle diameter of at least 100 particles are obtained. Then, the long diameter Di, the short diameter Ds, and the average particle diameter D of the particles are calculated using the respective number average values.
(6) Volume ratio of particles (C) to resin (B) After peeling the (A) layer from the stretched laminate, the particles (C) are removed from the resin (B), and the density ρ1 of the resin (B) is determined according to JIS- Measured based on K-7117. Further, the density ρ2 of the particles (C) is measured based on JIS R-1620. Moreover, the weight of resin (B) and particle | grains (C) is measured, and the weight% X of particle | grains (C) with respect to resin (B) is calculated | required. Then, the volume ratio is calculated from the following equation.
Volume ratio of particles (C) to resin (B) = (X / ρ2) / (X / ρ2 + (1-X) / ρ1)
(7) Friction coefficient Two oval samples are cut out from the stretched laminate, and stacked so that the (A) layer side of one sample and the layer side made of the resin (B) of the other sample are in contact with each other. Then, using AB-401 manufactured by Tester Sangyo Co., Ltd., the friction coefficient between the (A) layer of the stretched laminate and the layer made of the resin (B) is measured according to JIS-K7125.
(8) Surface resistance value The surface of the layer made of resin (B) of the stretched laminate is measured according to JIS-K7194 using a surface potentiometer S2002A and a surface potential measurement electrode.
(9) Planar evaluation An arbitrary portion 1 m ² of the stretched laminate is observed.
○: White dust and scratches are not observed on the film. × ... White dust and scratches are observed on the film. (10) Winding property The laminate is wound into a roll and the appearance is observed.
○: Has the same roll appearance as when using a masking film ×: Wrinkles cannot be wound up neatly (11) Time-lapse test A liquid crystal display device is manufactured using a laminate, and 80 ° C., 90 ° C. After 200 cycles of a heat cycle test for 1 hour in a% RH environment and at -20 ° C. in a 40% RH environment for 1 hour, the image display state of the liquid crystal display device is visually observed from the front.
Good: No abnormality is observed.
Defect: Partial hue change is observed at the edge of the screen.

(Production Example 1) Preparation of resin (B) solution containing particles (C) 4.2% of polyvinyl alcohol having a degree of saponification of 98.0 mol% and a degree of polymerization of 500 in a 75 ° C heated aqueous solution Particles selected according to description 1 were added with stirring using a twin mixer. After the temperature of this polyvinyl alcohol aqueous solution is lowered to room temperature, a mixed solvent of isopropanol and linear alkyl sulfonic acid soda is added, and Atray AS1000 (manufactured by Nippon Mining Co., Ltd.) is used as an antistatic agent. 20% by weight of the mixed solvent and 1% by weight of the antistatic agent were added little by little to the aqueous alcohol solution, and mixed and stirred for about 1 hour to prepare a resin (B) solution. The degree of saponification and the amount of added particles were variously adjusted to obtain the refractive index of the resin (B) and the volume ratio of the particles shown in Table 2.

(Examples 1-4)
After drying pellets of ZEONOR1420 (ZN1420) (manufactured by Nippon Zeon Co., Ltd.), which is a norbornene resin, at 100 ° C. for 5 hours, the pellets are fed to an extruder by a conventional method and melted at 250 ° C. and cooled from the die. The film was discharged on a drum to obtain an unstretched film (1) having a thickness of 150 μm. Subsequently, the unstretched film (1) was stretched 2.0 times in the longitudinal direction at a temperature of 150 ° C. by a longitudinal stretching machine using a float system between rolls to obtain a stretched film (2). . Furthermore, after applying the solution obtained in Production Example 1 to a single side of the stretched film (2) at a line speed of 50 m / min so that the film thickness after drying becomes 0.05 μm, The stretched film (2) was continuously stretched 2.0 times in the transverse direction at a temperature of 150 ° C. by a transverse stretching machine using a tenter method to obtain a laminate. Further, the obtained laminate was wound up continuously (line speed 50 m / min) to obtain a roll-like laminate having a width of 1350 mm and a length of 1500 m. The obtained laminate was at a level that could be sufficiently wound without using a masking film, no change in transparency was observed, and the surface shape of the laminate was good. Table 2 shows the physical properties and evaluation results of the obtained laminate.
The above laminate and a polarizing plate having a transmission axis in the longitudinal direction (manufactured by Sanlitz, HLC2-5618S, thickness 180 μm) were laminated by a roll-to-roll method to obtain a roll of an optical element. At this time, the laminate was laminated so that the slow axis of the laminate was substantially perpendicular to the absorption axis of the polarizing plate. The optical element cut out from the wound body was replaced with a polarizing plate on the backlight side of a commercially available vertical alignment (VA) mode liquid crystal display device, and incorporated so that the laminate was disposed on the liquid crystal cell side. When the display characteristics of the obtained liquid crystal display device were confirmed from the front by visual observation, the display was good and uniform.

(Comparative Example 1)
A laminate was obtained according to Example 1 (selecting resins and particles based on the descriptions in Tables 1 and 2). The obtained laminate was at a level that could be sufficiently wound without using a masking film, but deterioration of transparency and surface deterioration due to particle dropping were observed. Table 2 shows the physical properties and evaluation results of the obtained laminate.
In the same manner as in Example 1, the laminate obtained here and the polarizing plate were laminated by a roll-to-roll method to obtain a roll of an optical element. The optical element cut out from the wound body was replaced with a polarizing plate on the backlight side of a commercially available vertical alignment (VA) mode liquid crystal display device, and incorporated so that the laminate was disposed on the liquid crystal cell side. When the display characteristics of the obtained liquid crystal display device were confirmed from the front by visual observation, the display was poor.

(Comparative Example 2)
A laminate was obtained according to Example 1 (using the resins and particles described in Tables 1 and 2). However, the obtained laminate could not be wound due to wrinkles and breakage. There was no change in the transparency of the laminate, and the surface condition was good. Table 2 shows the physical properties and evaluation results of the obtained laminate.
In the same manner as in Example 1, an optical element was obtained by laminating a film cut out from the laminate obtained here and a film cut out from a polarizing plate (manufactured by Sanlitz, HLC2-5618S, thickness 180 μm). At this time, the laminate was laminated so that the slow axis of the laminate was substantially perpendicular to the absorption axis of the polarizing plate. This optical element was replaced with a polarizing plate on the backlight side of a commercially available vertical alignment (VA) mode liquid crystal display device, and incorporated so that the laminate was disposed on the liquid crystal cell side. When the display characteristics of the obtained liquid crystal display device were confirmed from the front by visual observation, the display was good.

(Comparative Example 3)
A laminate was obtained according to Example 1 (using the resins and particles described in Tables 1 and 2). The obtained laminate was at a level that could be sufficiently wound without using a masking film, but deterioration of transparency and surface deterioration due to the cause of particle dropping were observed. Table 2 shows the physical properties and evaluation results of the obtained laminate.
In the same manner as in Example 1, the laminate obtained here and the polarizing plate were laminated by a roll-to-roll method to obtain a roll of an optical element. The optical element cut out from the wound body was replaced with a polarizing plate on the backlight side of a commercially available vertical alignment (VA) mode liquid crystal display device, and incorporated so that the laminate was disposed on the liquid crystal cell side. When the display characteristics of the obtained liquid crystal display device were confirmed from the front by visual observation, the display was poor.

(Comparative Examples 4-6)
A laminate was obtained according to Example 1 (using the resins and particles described in Tables 1 and 2). The obtained laminate was at a level that could be sufficiently wound up without using a masking film, but the transparency was remarkably deteriorated. The planar shape of the laminate was good. Table 2 shows the physical properties and evaluation results of the obtained laminate.
In the same manner as in Example 1, the laminate obtained here and the polarizing plate were laminated by a roll-to-roll method to obtain a roll of an optical element. The optical element cut out from the wound body was replaced with a polarizing plate on the backlight side of a commercially available vertical alignment (VA) mode liquid crystal display device, and incorporated so that the laminate was disposed on the liquid crystal cell side. When the display characteristics of the obtained liquid crystal display device were confirmed from the front by visual observation, the display was poor.

The following can be seen from the results in Table 2.
As shown in Example 1, the stretched laminate of the present invention is a transparent film having an average particle size of 0.04 μm and a refractive index of 1.53 on a stretched film made of alicyclic polyolefin. It is added to the resin, and the amount of the particles added is 14% by volume with respect to the transparent resin. For this reason, this stretched laminate is excellent in transparency with no cloudiness, and no white dust or scratches are seen on its surface, and it can be wound up cleanly over a long length. Moreover, when the laminate of the present invention is used for a liquid crystal display device and the display performance is confirmed, a satisfactory display can be confirmed without any partial hue change at the edge of the screen, etc. Good characteristics.
As shown in Example 2, the stretched laminate of the present invention is a transparent film having an average particle size of 0.04 μm and a refractive index of 1.50 on a stretched film made of alicyclic polyolefin and having a refractive index of 1.54. It is added to the resin, and the amount of the particles added is 14% by volume with respect to the transparent resin. For this reason, this stretched laminate is excellent in transparency with no cloudiness, and no white dust or scratches are seen on its surface, and it can be wound up cleanly over a long length. In addition, when the stretched laminate of the present invention is used in a liquid crystal display device to check display performance, a good display can be confirmed without any partial hue change at the edge of the screen, etc. Display characteristics are good.
As shown in Example 3, the stretched laminate of the present invention is a transparent film having an average particle size of 0.06 μm and a refractive index of 1.55 on a stretched film made of alicyclic polyolefin. It is added to the resin, and the amount of the particles added is 14% by volume with respect to the transparent resin. For this reason, this stretched laminate is excellent in transparency with no cloudiness, and no white dust or scratches are seen on its surface, and it can be wound up cleanly over a long length. In addition, when the stretched laminate of the present invention is used in a liquid crystal display device to check display performance, a good display can be confirmed without any partial hue change at the edge of the screen, etc. Display characteristics are good.
As shown in Example 4, the stretched laminate of the present invention is a transparent film having an average particle size of 0.08 μm and a refractive index of 1.55 on a stretched film made of alicyclic polyolefin. It is added to the resin, and the amount of the particles added is 14% by volume with respect to the transparent resin. For this reason, this stretched laminate is excellent in transparency with no cloudiness, and no white dust or scratches are seen on its surface, and it can be wound up cleanly over a long length. In addition, when the stretched laminate of the present invention is used in a liquid crystal display device to check display performance, a good display can be confirmed without any partial hue change at the edge of the screen, etc. Display characteristics are good.
On the other hand, the stretched laminate of Comparative Example 1 is significantly different in average particle diameter of particles (C) and has a large value as compared with the above Examples. For this reason, this extending | stretching laminated body is inferior to transparency compared with the laminated body of an Example. In addition, although it can be wound almost neatly over a long length, white dust and scratches are seen on its surface. Further, when the stretched laminate of Comparative Example 1 is used for a liquid crystal display device and the display performance is confirmed, a partial hue change is observed at the edge of the screen or the like, resulting in poor display.
The stretched laminate of Comparative Example 2 has a significantly different average particle diameter of particles (C) and a smaller value compared to the above Examples. For this reason, this stretched laminate is excellent in transparency and does not show white dust or scratches on its surface, but when it is taken up into a roll, it is wrinkled or broken and cannot be taken up. When the stretched laminate of Comparative Example 2 was used for a liquid crystal display device and the display performance was confirmed, no partial hue change was observed at the edge of the screen and the like, and a good display could be confirmed. Display characteristics.
The stretched laminate of Comparative Example 3 is greatly different in the amount of particles (C) added and the value thereof is larger than that of the Example. For this reason, this extending | stretching laminated body is inferior to transparency compared with the laminated body of an Example. In addition, although it can be wound almost neatly over a long length, white dust and scratches are seen on its surface. In addition, when the stretched laminate of Comparative Example 3 was used for a liquid crystal display device and the display performance was confirmed, a partial hue change at the edge of the screen or the like was seen, resulting in poor display.
The stretched laminate of Comparative Example 4 differs greatly from the refractive index of the particles (C) and has a large value as compared with the above Examples. For this reason, this extending | stretching laminated body is inferior to transparency compared with the laminated body of an Example. In addition, white dust and scratches are not seen on the surface, and it can be wound up neatly over a long length. However, when the stretched laminate of Comparative Example 4 is used for a liquid crystal display device and the display performance is confirmed, a partial hue change is observed at the edge of the screen and the like, resulting in poor display.
The stretched laminate of Comparative Example 5 is significantly different in the refractive index of the particles (C) and small in value as compared with the above Examples. For this reason, this extending | stretching laminated body is inferior to transparency compared with the laminated body of an Example. In addition, white dust and scratches are not seen on the surface, and it can be wound up neatly over a long length. However, when the stretched laminate of Comparative Example 5 is used in a liquid crystal display device and the display performance is confirmed, a partial hue change is observed at the edge of the screen and the like, resulting in poor display.
The stretched laminate of Comparative Example 6 is significantly different in the refractive index of the resin (B) and smaller in value as compared with the above Examples. For this reason, this extending | stretching laminated body is inferior to transparency compared with the laminated body of an Example. In addition, white dust and scratches are not seen on the surface, and it can be wound up neatly over a long length. However, when the stretched laminate of Comparative Example 6 is used for a liquid crystal display device and the display performance is confirmed, a partial hue change is observed at the edge of the screen and the like, resulting in poor display.

Claims (5)

A polarizing plate having a stretched laminate formed by laminating a stretched film layer (A) obtained by stretching a film made of a transparent resin and a layer comprising a resin (B) containing particles (C),
Layer (A) is made of alicyclic polyolefin resin,
The resin (B) includes a polyvinyl alcohol polymer or an ethylene-vinyl alcohol copolymer,
The volume ratio of particles (C) to resin (B) is 1% to 30%,
The average particle size of the particles (C) is 0.01 to 0.10 μm,
The refractive indexes of the resin (B) and the particles (C) are both 1.50 to 1.55 ,
Polarizer haze and having an extended elongation laminate Ru der 0.2. 2. The polarizing plate according to claim 1, wherein the surface resistance of the layer made of the resin (B) is 1 × 10 ¹² Ω / □ or less. The polarizing plate according to claim 1, wherein the particles (C) are titanium oxide-silicon oxide based metal oxide. The polarizing plate according to claim 1, wherein the ethylene-vinyl alcohol copolymer contains 60 mol% or more of vinyl alcohol units. The liquid crystal display device which has a polarizing plate as described in any one of Claims 1-4.