JP2021086038A - Laminate and circularly polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated body capable of achieving protection of a circularly polarizing plate from ultraviolet rays and suppression of yellow coloring in a well-balanced manner. SOLUTION: A first resin layer made of a thermoplastic resin A containing a polymer containing an alicyclic structure and an ultraviolet absorber, and a second resin layer made of a thermoplastic resin B1 containing a polymer containing an alicyclic structure. Including a resin layer, the light transmittance at a wavelength of 390 nm is 0.1% or less, the light transmittance at a wavelength of 400 nm is 5% or less, and the light transmittance at a wavelength of 420 nm is 80% or more. A laminate having a resin layer thickness of 20 μm or less. [Selection diagram] Fig. 1

Description

The present invention relates to a laminate and a circularly polarizing plate.

The image display device may use a member such as a polarizer that is easily deteriorated by irradiation with ultraviolet rays. In order to protect such a member from ultraviolet rays, a protective film having a function of absorbing ultraviolet rays may be combined with the member. For example, as a protective film to be combined with a polarizer, a film containing a predetermined ultraviolet absorber A and a predetermined ultraviolet absorber B is known (Patent Document 1).
Further, a compound described in Patent Document 2 is known as an additive for imparting an ultraviolet absorbing ability to a resin.

JP-A-2015-165301 International Publication No. 2016/021664

An image display device such as an organic electroluminescence (EL) image display device may be provided with a polarizing plate. Examples of the provided polarizing plate include a circular polarizing plate for suppressing reflection of external light. As the circularly polarizing plate, for example, a film containing a liquid crystal cured layer having cholesteric regularity can be used. Such a liquid crystal cured layer is formed, for example, by forming a layer having cholesteric regularity from a liquid crystal composition containing a liquid crystal compound having polymerizability and curing the layer while maintaining the cholesteric regularity. The liquid crystal cured layer is liable to be deteriorated by irradiation with ultraviolet rays. Therefore, a protective film may be laminated on the circularly polarizing plate in order to protect the circularly polarizing plate (for example, the circularly polarizing plate including the liquid crystal cured layer) from ultraviolet rays.

On the other hand, if the protective film itself appears to be colored yellow, the original color displayed by the image display device may not be displayed correctly.

Therefore, there is a need for a laminate that can achieve a good balance between protection of the circularly polarizing plate from ultraviolet rays and suppression of yellow coloring. Here, it is assumed that the circularly polarized light includes elliptically polarized light in addition to completely circularly polarized light.

The present inventor has diligently studied to solve the above problems. As a result, they have found that the above problems can be solved by defining the transmittance of light having a predetermined wavelength, and have completed the present invention.
That is, the present invention provides the following.

（式中、Ｒ^１は、アルキル基、シクロアルキル基、アルキルチオアルキル基、アルケニル基、アリール基、又はアリールアルキル基を表す。）
［５］ Ｒ^１が、アルキル基である、［４］に記載の積層体。
［６］ 長尺の積層体であって、面内レターデーションが、７０ｎｍ以上１５０ｎｍ未満であり、遅相軸と長手方向とがなす角度が、４５°±５°の範囲にある、［１］〜［５］のいずれか一項に記載の積層体。
［７］ 脂環式構造を含有する重合体を含む熱可塑性樹脂Ｂ２からなる第三樹脂層を更に含み、前記第一樹脂層の一方の面上に前記第二樹脂層が設けられ、前記第一樹脂層の他方の面上に前記第三樹脂層が設けられている、［１］〜［６］のいずれか一項に記載の積層体。
［８］ ［１］〜［７］のいずれか一項に記載の積層体と、円偏光子とを含む、円偏光板。 [1] A first resin layer made of a thermoplastic resin A containing a polymer containing an alicyclic structure and an ultraviolet absorber, and
A second resin layer made of a thermoplastic resin B1 containing a polymer containing an alicyclic structure is included.
The light transmittance at a wavelength of 390 nm is 0.1% or less, the light transmittance at a wavelength of 400 nm is 5% or less, and the light transmittance at a wavelength of 420 nm is 80% or more.
A laminate having a thickness of 20 μm or less of the first resin layer.
[2] The laminate according to [1], wherein the value of b ^{* in the L *} a ^* b ^{* color system is 0.7 or more and 2.0 or less.}
[3] The laminate according to [1] or [2], wherein the thermoplastic resin A contains a compound I having a benzotriazole ring and a sulfur atom.
[4] The laminate according to [3], wherein the compound I is a compound represented by the following formula (i).

(In the formula, R ¹ represents an alkyl group, a cycloalkyl group, an alkylthioalkyl group, an alkenyl group, an aryl group, or an arylalkyl group.)
[5] The laminate according to [4], wherein ^{R 1 is an alkyl group.}
[6] A long laminate having an in-plane retardation of 70 nm or more and less than 150 nm, and an angle formed by the slow axis and the longitudinal direction in the range of 45 ° ± 5 ° [1]. The laminate according to any one of [5].
[7] A third resin layer made of a thermoplastic resin B2 containing a polymer containing an alicyclic structure is further contained, and the second resin layer is provided on one surface of the first resin layer. The laminate according to any one of [1] to [6], wherein the third resin layer is provided on the other surface of the one resin layer.
[8] A circularly polarizing plate containing the laminate according to any one of [1] to [7] and a circularly polarizing element.

According to the present invention, it is possible to provide a laminate capable of achieving protection of a circularly polarizing plate from ultraviolet rays and suppression of yellow coloring in a well-balanced manner.

FIG. 1 is a cross-sectional view schematically showing a laminated body according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a laminated body according to another embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a circularly polarizing plate according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, the "long" film means a film having a length of 5 times or more, preferably 10 times or more, and specifically a roll. A film that has a length that allows it to be rolled up and stored or transported. The upper limit of the length of the film is not particularly limited, and may be, for example, 100,000 times or less with respect to the width.

In the following description, "λ / 2 plate", "λ / 4 plate", "polarizing plate", "circular polarizing plate", and "phase difference plate" are not limited to rigid members unless otherwise specified. Also included are flexible members such as resin films.

In the following description, the slow axis of the film or layer represents the slow axis in the plane of the film or layer unless otherwise specified.

In the following description, the in-plane retardation Re of the layer is a value represented by Re = (nx-ny) × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and in the direction in which the maximum refractive index is given. ny represents the refractive index in the in-plane direction of the layer and orthogonal to the nx direction. d represents the thickness of the layer. The measurement wavelength is 590 nm unless otherwise specified.

In the following description, unless otherwise specified, the direction of the element is "orthogonal", and includes an error within a range that does not impair the effect of the present invention, for example, within a range of ± 3 °, ± 2 °, or ± 1 °. You may be.

As used herein, the term "agent" may be a single substance or may include a plurality of substances.

[1. Laminated body]
[1.1. Overview of laminated body]
The laminate according to the embodiment of the present invention includes a first resin layer made of a polymer containing an alicyclic structure and a thermoplastic resin A containing an ultraviolet absorber, and a polymer containing an alicyclic structure. Includes a second resin layer made of thermoplastic resin B1.
The laminate has a light transmittance of usually 0.1% or less at a wavelength of 390 nm, a light transmittance of usually 5% or less at a wavelength of 400 nm, and a light transmittance of usually 80% or more at a wavelength of 420 nm. The thickness of the resin layer is 20 μm or less.

The light transmittance at a wavelength of 390 nm is usually 0.1% or less, preferably less than 0.08%, more preferably 0.07% or less, and the lower the thickness, the more preferably 0% or more.
The light transmittance at a wavelength of 400 nm is usually 5% or less, preferably 4.5% or less, more preferably 4% or less, and lower is preferable, but usually 0% or more.
Further, the laminated body has a light transmittance of usually 80% or more, preferably 82% or more, more preferably 84% or more at a wavelength of 420 nm, and the higher it is from the viewpoint of suppressing the color of the laminated body from becoming yellow. It is preferable, but it is preferably 90% or less, more preferably 90% or less, from the viewpoint of achieving a particularly well-balanced effect of suppressing the yellowing of the laminate and the effect of protecting the member combined with the laminate from light rays having a wavelength of 420 nm. Is 88% or less.
By keeping the light transmittance at wavelengths of 390 nm, 400 nm, and 420 nm of the laminated body within the above range, the effect of suppressing the color of the laminated body from turning yellow and the effect of suppressing the deterioration of the member combined with the laminated body are obtained. Can be realized in a well-balanced manner.

The yellowness of the laminate can be evaluated by measuring the color of the laminate with a color difference meter and obtaining the value of b ^{* in the L *} a ^* b ^{* color system.} It can be evaluated that the smaller the value of ^{b *, the less yellowish the color.} The measurement by the colorimetric color difference meter can be performed using a C light source under the conditions of a viewing angle of 2 ° and a transmission mode for measuring the transmitted light of the laminated body.

In the laminated body, the value of b ^{* in the L *} a ^* b ^* color system is preferably 0.7 or more, more preferably 0.8 or more, still more preferably 0.9 or more, and preferably 2.0. Below, it is more preferably 1.7 or less, still more preferably 1.5 or less. When the value of b ^* of the laminated body falls within the above range, deterioration of the member combined with the laminated body can be effectively suppressed.

The thickness of the laminate is preferably 25 μm or less, more preferably 23 μm or less, still more preferably 20 μm or less, usually larger than 0 μm, and preferably 15 μm or more. When the thickness of the laminate is within the above range, the laminate can effectively absorb ultraviolet rays and the laminate can be made thinner.

FIG. 1 is a cross-sectional view schematically showing a laminated body according to an embodiment of the present invention. As shown in FIG. 1, the laminate 100 includes a first resin layer 101 and a second resin layer 102. The second resin layer 102 is provided on one surface 101U of the first resin layer 101. The second resin layer 102 and the first resin layer 101 are in direct contact with each other. Hereinafter, each component of the laminated body will be described in detail.

[1.2. First resin layer]
The first resin layer is made of the thermoplastic resin A and is formed of the thermoplastic resin A. The thermoplastic resin A contains a polymer containing an alicyclic structure and an ultraviolet absorber.

(Polymer containing an alicyclic structure)
In a polymer containing an alicyclic structure, the structural unit of the polymer contains an alicyclic structure. A polymer containing an alicyclic structure usually has excellent moisture and heat resistance. Therefore, by using a polymer containing an alicyclic structure, the moisture and heat resistance of the optical film can be improved.

The polymer containing an alicyclic structure may have an alicyclic structure in the main chain or an alicyclic structure in the side chain. Among them, a polymer having an alicyclic structure in the main chain is preferable from the viewpoint of mechanical strength and heat resistance.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among them, a cycloalkane structure and a cycloalkene structure are preferable, and a cycloalkane structure is particularly preferable, from the viewpoint of mechanical strength and heat resistance.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, still more preferably 20 or less, per alicyclic structure. Is in the range of 15 or less. When the number of carbon atoms constituting the alicyclic structure is in this range, the mechanical strength, heat resistance and moldability of the resin containing the polymer containing the alicyclic structure are highly balanced.

In the polymer containing an alicyclic structure, the proportion of structural units having an alicyclic structure is preferably 55% by weight or more, more preferably 70% by weight or more, still more preferably 90% by weight or more. When the ratio of the structural units having the alicyclic structure in the polymer containing the alicyclic structure is in this range, the transparency and heat resistance of the resin containing the polymer containing the alicyclic structure are good.

Examples of the polymer containing an alicyclic structure include a norbornene-based polymer, a monocyclic cyclic olefin-based polymer, a cyclic conjugated diene-based polymer, a vinyl alicyclic hydrocarbon polymer, and hydrogen additives thereof. Can be mentioned. Among these, norbornene-based polymers and hydrogenated products thereof are more preferable because they have good transparency and moldability.

Examples of the norbornene-based polymer and its hydrogenated product include a ring-opening polymer of a monomer having a norbornene structure and a hydrogenated product thereof; an addition polymer of a monomer having a norbornene structure and a hydrogenated product thereof. Be done. Examples of ring-opening polymers of monomers having a norbornene structure include a ring-opening copolymer of one type of monomer having a norbornene structure and ring-opening of two or more types of monomers having a norbornene structure. Examples thereof include a copolymer and a ring-opening copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Further, as an example of the addition polymer of the monomer having a norbornene structure, the addition homopolymer of one kind of monomer having a norbornene structure and the addition copolymer of two or more kinds of monomers having a norbornene structure , And an addition copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Examples of these polymers include polymers disclosed in JP-A-2002-321302. Among these, a hydrogenated compound of a monomeric ring-opening polymer having a norbornene structure is particularly suitable from the viewpoints of moldability, heat resistance, low hygroscopicity, dimensional stability and light weight.

Suitable specific examples of the norbornene-based polymer and hydrogenated products thereof include "Zeonor" manufactured by Zeon Corporation; "Arton" manufactured by JSR Corporation; and "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

The weight average molecular weight (Mw) of the polymer containing an alicyclic structure is preferably 10,000 or more, more preferably 15,000 or more, still more preferably 20,000 or more, and preferably 100,000 or less. It is more preferably 80,000 or less, still more preferably 50,000 or less. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the layer containing the polymer containing this alicyclic structure are highly balanced.

The molecular weight distribution (Mw / Mn) of the polymer containing an alicyclic structure is preferably 1.2 or more, more preferably 1.5 or more, still more preferably 1.8 or more, and preferably 3.5 or less. , More preferably 3.0 or less, still more preferably 2.7 or less. Here, Mn represents a number average molecular weight. When the molecular weight distribution is at least the lower limit of the above range, the productivity of the polymer containing the alicyclic structure can be increased and the production cost can be suppressed. Further, when it is not more than the upper limit value, the amount of the low molecular weight component becomes small, so that relaxation at the time of high temperature exposure can be suppressed and the stability of the layer containing the polymer containing the alicyclic structure can be enhanced. ..

The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured as polyisoprene or polystyrene-equivalent weight average molecular weight by gel permeation chromatography using cyclohexane as a solvent. In the gel permeation chromatography described above, toluene may be used as the solvent if the sample is insoluble in cyclohexane.

The glass transition temperature of the polymer containing an alicyclic structure is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, further preferably 120 ° C. or higher, preferably 170 ° C. or lower, more preferably 150 ° C. or lower. More preferably, it is 140 ° C. or lower. When the glass transition temperature of the polymer containing an alicyclic structure is equal to or higher than the lower limit of the above range, the durability of the laminate in a high temperature environment can be enhanced, and when it is equal to or lower than the upper limit of the above range. In addition, the laminating body can be easily stretched.

The thermoplastic resin A may contain one kind of polymer containing an alicyclic structure alone, or may contain any combination of two or more kinds.

The content of the polymer containing the alicyclic structure in the thermoplastic resin A is preferably 75% by weight or more, more preferably 80% by weight or more, still more preferably 85% by weight or more, and usually less than 100% by weight. It is preferably 99% by weight or less, more preferably 95% by weight or less, and further preferably 90% by weight or less. As a result, the thermoplastic resin A can be effectively imparted with properties such as moisture and heat resistance of the polymer containing the alicyclic structure.

(UV absorber)
The ultraviolet absorber means an agent capable of absorbing ultraviolet rays. Here, the ultraviolet ray means light having a wavelength of 400 nm or less. As the ultraviolet absorber, it is preferable to use an organic ultraviolet absorber, which is an organic compound, because it has good solubility or dispersibility in the resin. Examples of organic UV absorbers are triazine UV absorbers, benzophenone UV absorbers, benzotriazole UV absorbers, acrylonitrile UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, naphthalimide UV absorbers. Examples include an ultraviolet absorber and a phthalocyanine-based ultraviolet absorber.

As the ultraviolet absorber, a compound having an absorption maximum in a wavelength range of 360 nm or more and 400 nm or less, and having a maximum absorption wavelength in a wavelength range of 250 nm or more and 800 nm or less in a wavelength range of 360 nm or more and 400 nm or less is used. By using such a compound as an ultraviolet absorber, the effect of the present application can be remarkably obtained with a small number of types (for example, two or one type) of ultraviolet absorbers.

From the viewpoint of remarkably obtaining the effects of the present application, the ultraviolet absorber is preferably a benzotriazole-based ultraviolet absorber, and more preferably an ultraviolet absorber having a benzotriazole ring and a sulfur atom.

Examples of UV absorbers having a benzotriazole ring and a sulfur atom include compounds disclosed in WO 2016/021664.

As the compound having a benzotriazole ring and a sulfur atom that can be used as an ultraviolet absorber (hereinafter, also referred to as compound I), a compound represented by the following formula (i) is preferable.

In the above formula (i), R ¹ represents an alkyl group, a cycloalkyl group, an alkylthioalkyl group, an alkenyl group, an aryl group, or an arylalkyl group. t-Bu represents a tert-butyl group.

The alkyl group may be linear or branched. The number of carbon atoms of the alkyl group is preferably 1 to 20, more preferably 1 to 15, still more preferably 1 to 10, and even more preferably 1 to 8.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a butane-2-yl group, a 2-methylpropan-1-yl group, a pentyl group, a pentan-2-yl group, and a hexyl group. Examples thereof include a heptyl group, an octyl group, a nonyl group, a decyl group and a dodecyl group.

The cycloalkyl group may be a monocyclic group, a dicyclic group, or a group in which these are bonded by a single bond. The number of carbon atoms of the cycloalkyl group is preferably 3 to 10, more preferably 5 to 6, and even more preferably 6.
Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Examples of alkyl groups in alkylthioalkyl groups are similar to those described for alkyl groups. The number of carbon atoms of the alkylthio group in the alkylthioalkyl group is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10. The number obtained by subtracting the number of carbon atoms of the alkylthio group from the number of carbon atoms of the alkylthioalkyl group is preferably 1 to 20, more preferably 1 to 15, and further preferably 1 to 10.

The alkenyl group may be linear or branched. The number of carbon atoms of the alkenyl group is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10. Specific examples of the alkenyl group include an ethenyl group and an allyl group.

The aryl group may have a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms. The number of carbon atoms of the aryl group does not include the number of carbon atoms of the substituent, and is preferably 6 to 20, more preferably 6 to 15, and even more preferably 6 to 10.
Specific examples of the aryl group include a phenyl group, a tolyl group, and a naphthyl group.

The aryl group in the arylalkyl group may have a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms. The number of carbon atoms of the aryl group in the arylalkyl group does not include the number of carbon atoms of the substituent, and is preferably 6 to 20, more preferably 6 to 15, and even more preferably 6 to 10.
The number of carbon atoms of the alkyl group in the arylalkyl group is preferably 1 to 20, more preferably 1 to 15, still more preferably 1 to 10, still more preferably 1 to 5, and most preferably 1 to 3.
Specific examples of the arylalkyl group include a benzyl group and a phenylethyl group.

From the viewpoint of obtaining the effect of the present application remarkably, R ¹ is preferably an alkyl group.

The content of the ultraviolet absorber in the thermoplastic resin A can be determined so that the light transmittance of the laminate is within a desired range, but is preferably 1% by weight or more, more preferably 5% by weight or more, still more preferably 6. It is 5% by weight or more, preferably 25% by weight or less, more preferably 20% by weight or less, still more preferably 15% by weight or less. By setting the content of the ultraviolet absorber to the above lower limit value or more, the ultraviolet transmittance of the laminated body can be effectively suppressed. Further, by setting the content of the ultraviolet absorber to be equal to or less than the upper limit value, it is possible to suppress a decrease in the light transmittance of visible light.

The ultraviolet absorber contained in the thermoplastic resin A may be used alone or in any combination of two or more kinds. For example, the thermoplastic resin A may contain one type of compound I alone, may contain two or more types of compound I, and may contain an ultraviolet absorber other than compound I and compound I. ..

When the thermoplastic resin A contains the compound I, the ratio of the total amount of the compound I to the total amount of the ultraviolet absorber contained in the thermoplastic resin A is preferably 60% by weight or more, more preferably 70% by weight or more. It is more preferably 80% by weight or more, usually 100% by weight or less, and may be 100% by weight.

The thermoplastic resin A may further contain any component in addition to the polymer containing the alicyclic structure and the ultraviolet absorber.
Examples of optional components include polymers other than polymers containing an alicyclic structure; plasticizers; optical brighteners; dispersants; heat stabilizers; light stabilizers; antistatic agents; antioxidants; surfactants; Activators can be mentioned. Any component may be contained in the thermoplastic resin A alone or as a combination of two or more kinds in any ratio.

(Thickness of first resin layer)
The thickness of the first resin layer can be arbitrarily set according to the content of the ultraviolet absorber in the thermoplastic resin A, the overall thickness of the laminate, and the like, but is preferably 5 μm or more, more preferably 8 μm or more, and further. It is preferably 10 μm or more, usually 20 μm or less, preferably 18 μm or less, and more preferably 15 μm or less.
When the thickness of the first resin layer is at least the above lower limit value, the laminated body can be effectively provided with the ultraviolet absorbing function. When it is not more than the upper limit value, the laminate can be made thinner.

[1.3. Second resin layer]
The second resin layer is made of the thermoplastic resin B1 and is formed of the thermoplastic resin B1. The thermoplastic resin B1 contains a polymer containing an alicyclic structure.

Examples of the polymer containing an alicyclic structure contained in the thermoplastic resin B1 and preferred examples include examples of a polymer containing an alicyclic structure contained in the thermoplastic resin A and examples similar to the preferred examples. Can be mentioned.

The polymer containing the alicyclic structure contained in the thermoplastic resin B1 is a different polymer even if it is the same polymer as the polymer containing the alicyclic structure contained in the thermoplastic resin A. Although it may be used, it is preferably the same polymer.

The content of the polymer containing an alicyclic structure in the thermoplastic resin B1 is preferably 90% by weight or more, more preferably 95% by weight or more, still more preferably 98% by weight or more, and usually 100% by weight or less. It may be 100% by weight. As a result, the thermoplastic resin B1 can be effectively imparted with properties such as moisture and heat resistance of the polymer containing an alicyclic structure.

The thermoplastic resin B1 may contain an ultraviolet absorber in addition to the polymer containing an alicyclic structure. However, from the viewpoint of suppressing the bleed-out of the ultraviolet absorber, the content of the ultraviolet absorber in the thermoplastic resin B1 is preferably 3% by weight or less, more preferably 1% by weight or less, still more preferably 0.5% by weight. It is usually 0% by weight or more, and may be substantially 0% by weight or 0% by weight.

The thermoplastic resin B1 may further contain an arbitrary component in addition to the polymer containing an alicyclic structure. Examples of the arbitrary component include the same examples as those mentioned as the optional component that can be contained in the thermoplastic resin A. Any component may be contained in the thermoplastic resin B1 alone or as a combination of two or more kinds in any ratio.

(Thickness of second resin layer)
The thickness of the second resin layer is preferably 1 μm or more, more preferably 2 μm or more, further preferably 3 μm or more, preferably 10 μm or less, more preferably 9 μm or less, still more preferably 8 μm or less. When the thickness of the second resin layer is at least the above lower limit value, bleeding out of the ultraviolet absorber from the first resin layer can be effectively suppressed. When it is not more than the upper limit value, the laminate can be made thinner.

The ratio of the thickness of the second resin layer to the thickness of the first resin layer (second resin layer / first resin layer) is preferably 1/20 or more, more preferably 1/10 or more, and preferably 2 /. It is 1 or less, more preferably 1/1 or less. When the ratio is at least the lower limit value, bleeding out of the ultraviolet absorber from the first resin layer can be effectively suppressed. When it is not more than the upper limit value, the laminate can be made thinner.

[1.4. Any layer]
The laminate may include any layer in addition to the first resin layer and the second resin layer described above.
Examples of the arbitrary layer include the third resin layer described below.
The laminate according to another embodiment of the present invention includes the first resin layer, the second resin layer, and the third resin layer. The third resin layer is made of a thermoplastic resin B2 containing a polymer containing an alicyclic structure. The second resin layer is provided on one surface of the first resin layer, and the third resin layer is provided on the other surface of the first resin layer.

FIG. 2 is a cross-sectional view schematically showing a laminated body according to another embodiment of the present invention. As shown in FIG. 2, the laminate 200 includes a second resin layer 202, a first resin layer 201, and a third resin layer 203 in this order. The second resin layer 202 is provided on one surface 201U of the first resin layer 201 and is in direct contact with the first resin layer 201. The third resin layer 203 is provided on the other surface 201D of the first resin layer 201 and is in direct contact with the first resin layer 201.

(Third resin layer)
The third resin layer is made of the thermoplastic resin B2 and is formed of the thermoplastic resin B2. The thermoplastic resin B2 contains a polymer containing an alicyclic structure.

Examples of the polymer containing an alicyclic structure contained in the thermoplastic resin B2 and preferred examples include examples of a polymer containing an alicyclic structure contained in the thermoplastic resin A and examples similar to the preferred examples. Can be mentioned.

The polymer containing the alicyclic structure contained in the thermoplastic resin B2 is a different polymer even if it is the same polymer as the polymer containing the alicyclic structure contained in the thermoplastic resin A. Although it may be used, it is preferably the same polymer.

The polymer containing the alicyclic structure contained in the thermoplastic resin B2 is a different polymer even if it is the same polymer as the polymer containing the alicyclic structure contained in the thermoplastic resin B1. It may be, but it is preferably the same polymer.
The content of the polymer containing an alicyclic structure in the thermoplastic resin B2 can be preferably in the same range as the range of the polymer containing an alicyclic structure in the thermoplastic resin B1.

Further, the thermoplastic resin B2 may contain an ultraviolet absorber in addition to the polymer containing an alicyclic structure. However, similarly to the second resin layer, the content of the ultraviolet absorber in the thermoplastic resin B2 is preferably contained in the thermoplastic resin B1 from the viewpoint of suppressing the bleed-out of the ultraviolet absorber in the third resin layer. It can be in the same range as the rate.

The thermoplastic resin B2 may further contain an arbitrary component in addition to the polymer containing an alicyclic structure. Examples of the arbitrary component include the same examples as those mentioned as the optional component that can be contained in the thermoplastic resin A. Any component may be contained in the thermoplastic resin B2 alone or as a combination of two or more kinds in any ratio.

The thermoplastic resin B2 may be a resin different from that of the thermoplastic resin B1 or may be the same resin. For example, the thermoplastic resin B2 may be a resin containing a polymer containing an alicyclic structure, which is different from the thermoplastic resin B1, or may be a resin having a different glass transition temperature. However, from the viewpoint of facilitating the production of the laminated body and suppressing curling of the laminated body, it is preferable that the thermoplastic resin B1 and the thermoplastic resin B2 are the same resin.

(Thickness of third resin layer)
The thickness of the third resin layer can preferably be in the same range as the thickness range of the second resin layer. As a result, it is possible to effectively prevent the ultraviolet absorber from bleeding out from the first resin layer. The thickness of the third resin layer is preferably 0.9 times or more, more preferably 0.95 times or more, still more preferably 0.99 times or more, and preferably 1.1 times the thickness of the second resin layer. Hereinafter, it is more preferably 1.05 times or less, further preferably 1.01 times or less, and may be 1.0 times, and particularly preferably 1.0 times. Thereby, the curl of the laminated body can be effectively suppressed.

(Any other layer)
Examples of another arbitrary layer include a hard coat layer and an adhesive layer (including an adhesive layer (pressure sensitive adhesive layer); the same applies hereinafter). The arbitrary layer may be provided, for example, between the first resin layer and the second resin layer, may be provided between the first resin layer and the third resin layer, and may be provided between the first resin layer and the third resin layer. It may be provided on the surface of the layer, may be provided on the surface of the third resin layer, or may be provided on the outermost side of the laminate.

[1.5. Characteristics of laminated body]
The laminate may have optical isotropic properties or may have optical anisotropy. The laminate may have, for example, an in-plane retardation that functions as a λ / 2 plate or a λ / 4 plate. If the laminate has an in-plane retardation that functions as a λ / 4 plate, the laminate may be incorporated into a liquid crystal image display device to make the liquid crystal image display device visible through polarized sunglasses.
The laminate has, for example, an in-plane retardation of preferably 60 nm or more, more preferably 65 nm or more, still more preferably 70 nm or more, preferably 150 nm or less, more preferably less than 150 nm, still more preferably 130 nm or less.

The laminate may be long. When the laminate is long and the in-plane retardation is larger than 0 nm, the range of the angle between the slow axis of the laminate and the longitudinal direction of the laminate is preferably 45 ° ± 5 °. It is more preferably 45 ° ± 3 °, and even more preferably 45 ° ± 1 °. As a result, the laminate and a long optical film such as a linear polarizer having an absorption axis in the longitudinal direction or the width direction and a film having a slow axis in the longitudinal direction or the width direction can be rolled to roll. By laminating, an optical laminate such as a long polarizing plate and a long retardation plate can be efficiently manufactured.

[1.6. Laminated body manufacturing method]
The laminate can be produced by any method. For example, the laminate is formed by co-extruding the thermoplastic resin A, the thermoplastic resin B1, and the thermoplastic resin B2 when the laminate contains a third resin layer (co-extrusion molding step). It can be manufactured by the method including. Examples of the method for extruding each resin include a coextrusion T-die method, a coextrusion inflation method, and a coextrusion lamination method. Above all, the coextrusion T-die method is preferable.

The method for producing the laminate may include a stretching step. The stretching step is, for example, a longitudinal stretching step of stretching the unstretched body in the longitudinal direction, a transverse stretching step of stretching the unstretched body in the width direction orthogonal to the transport direction, and neither the longitudinal direction nor the lateral direction of the unstretched body. An oblique stretching step of stretching in a direction can be mentioned. The stretching step may be a step of sequentially stretching the unstretched body in two or more directions, or a step of simultaneously stretching the unstretched body in two directions. The stretching step can impart the desired retardation to the laminate.

[2. Circularly polarized light]
The laminate can be suitably used in combination with any member to protect the member from ultraviolet light. The laminate can be combined with members such as, for example, linear and circular polarizers, retardation plates, and the like.
In particular, the laminate can be suitably used as a circularly polarized light protective film for protecting the circularly polarized light from ultraviolet rays in combination with the circularly polarized light.

The circularly polarizing plate according to the embodiment of the present invention includes the above-mentioned laminated body and a circularly polarizing element. FIG. 3 is a cross-sectional view schematically showing a circularly polarizing plate according to an embodiment of the present invention.
The circularly polarizing plate 1000 includes a circularly polarizing element 1001 and the above-mentioned laminated body 200. As described above, the laminate 200 includes the second resin layer 202, the first resin layer 201, and the third resin layer 203 in this order. In the present embodiment, the circularly polarized lighter 1001 and the laminated body 200 are laminated so that the second resin layer 202 is arranged between the circularly polarized lighter 1001 and the first resin layer 201. Further, the circularly polarized light element 1001 and the second resin layer 202 are in direct contact with each other. In another embodiment, the circularly polarized lighter 1001 and the laminated body 200 may be laminated so that the third resin layer 203 is arranged between the circularly polarized lighter 1001 and the first resin layer 201.
In yet another embodiment, the circularly polarizing plate may include the laminated body 100 instead of the laminated body 200. At that time, the circularly polarized light and the laminated body 100 may be laminated so that the first resin layer 101 is arranged between the circularly polarized light and the second resin layer 102, or the circularly polarized light and the first resin layer 102. The circularly polarized light and the laminated body 100 may be laminated so that the first resin layer 101 is arranged between the two resin layers 102.

The circular polarized light is an optical element having a function of transmitting one of circularly polarized light having a counterclockwise or counterclockwise rotation direction and reflecting or absorbing a part or all of the other. Examples of circularly polarized light include a circularly polarized lighter including a linear polarized lighter and a layer functioning as a λ / 4 plate, and a circularly polarized lighter including a layer of a resin having cholesteric regularity.

Cholesteric regularity means that the molecular axes are aligned in a certain direction on a certain plane inside the material, but the direction of the molecular axes shifts at a slight angle on the next plane that overlaps with it, and further angles on the next plane. It is a structure in which the angle of the molecular axis in the plane shifts (twists) as it sequentially passes through the planes that are arranged in an overlapping manner. That is, when the molecules inside a layer of a material have cholesteric regularity, the molecules are aligned so that their molecular axes are oriented in a certain direction on a first plane inside the layer. In the next second plane that overlaps the first plane inside the layer, the direction of the molecular axis deviates slightly from the direction of the molecular axis in the first plane. In the next third plane that further overlaps the second plane, the direction of the molecular axis is further angled from the direction of the molecular axis in the second plane. In this way, in the planes that are arranged in an overlapping manner, the angles of the molecular axes in the planes are sequentially shifted (twisted). Such a structure in which the direction of the molecular axis is twisted is usually a spiral structure and an optically chiral structure.

An example of a layer of a resin having cholesteric regularity that can be contained in a circular polarizing element is a liquid crystal cured layer obtained by curing a liquid crystal composition containing a polymerizable liquid crystal compound. Here, the material referred to as a "liquid crystal composition" for convenience includes not only a mixture of two or more substances but also a material composed of a single substance. The polymerizable liquid crystal compound is a liquid crystal compound that can be polymerized in a liquid crystal composition in a state of exhibiting a liquid crystal phase and can be a polymer while maintaining the orientation of molecules in the liquid crystal phase.

Examples of the polymerizable liquid crystal compound include a liquid crystal compound having a polymerizable group. Specific examples of the liquid crystal compound having a polymerizable group include JP-A-11-513360, JP-A-2002-030042, JP-A-2004-204190, JP-A-2005-263789, and JP-A-2007-. Examples thereof include rod-shaped liquid crystal compounds having a polymerizable group described in JP-A-119415, JP-A-2007-186430, and the like.

When a polymerizable liquid crystal compound contained in the liquid crystal composition is oriented as a liquid crystal composition for forming a layer of a resin having cholesteric regularity, the polymerizable liquid crystal compound is a liquid crystal having cholesteric regularity. A composition that can exhibit a phase (cholesteric liquid crystal phase) and can be polymerized in the liquid crystal composition in the state of exhibiting such a liquid crystal phase can be used. Hereinafter, a liquid crystal composition capable of forming a resin layer having cholesteric regularity is also referred to as a cholesteric liquid crystal composition.

As the cholesteric liquid crystal composition, a liquid crystal composition containing a polymerizable liquid crystal compound and, if necessary, any component can be used. As the cholesteric liquid crystal composition, for example, those described in International Publication No. 2016/002765 can be used. An example of a method of forming a resin layer having cholesteric regularity from a liquid crystal composition is a method of providing a layer of the liquid crystal composition on a base material and curing the layer.

The liquid crystal cured layer obtained by curing the liquid crystal composition is liable to be deteriorated by ultraviolet rays, particularly ultraviolet rays having a wavelength of 250 nm to 410 nm. Therefore, the circularly polarizing plate including the liquid crystal cured layer is generally liable to be deteriorated by ultraviolet rays.
However, since the circularly polarizing plate according to the embodiment of the present invention contains a predetermined laminated body in which the ultraviolet transmittance of a specific wavelength is suppressed to be low, deterioration due to ultraviolet rays is effectively suppressed.

For example, the maximum rate of change of the in-plane retardation ratio after the test with respect to the in-plane retardation ratio of the circularly polarizing plate before the spectroscopic aging test is preferably less than 5%, ideally 0%. It may be 0% or more.
Here, the spectroscopic aging test is carried out under the condition that the circularly polarizing plate is irradiated with 100 W of light at 40 ° C. for 24 hours, and the in-plane retardation ratio is that of the in-plane retardation Re (450) at a wavelength of 450 nm. It is a ratio to the in-plane retardation Re (550) at a wavelength of 550 nm. The maximum rate of change is the maximum value among the absolute values of the rate of change measured with a wavelength interval of 2 nm in the wavelength range of 250 nm to 420 nm. The absolute value of the rate of change is determined by | X-100 | (%), where the in-plane retardation ratio before the spectroscopic aging test is 100% and the in-plane retardation ratio after the spectroscopic aging test is X%.

The thickness of the circularly polarizing plate according to the embodiment of the present invention is preferably 7 μm or more, more preferably 12 μm or more, preferably 35 μm or less, and more preferably 30 μm or less. Since the thickness of the laminated body included in the circularly polarizing plate is thin, the thickness of the circularly polarizing plate including the laminated body can also be reduced.

The circularly polarizing plate may include any layer other than the laminated body and the circularly polarized light. Examples of the arbitrary layer include an adhesive layer (including an adhesive layer (pressure sensitive adhesive layer)) for adhering the laminate and the circularly polarizing element, and a hard coat layer.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "%" and "part" representing quantities are based on weight unless otherwise specified. The operations described below were performed under normal temperature and pressure conditions unless otherwise specified.

[Evaluation method]
(Glass-transition temperature)
The measurement was performed using a differential scanning calorimeter (“DSC6200” manufactured by Seiko Instruments) under the condition of a heating rate of 20 ° C./min.

(Thickness of each layer and laminate)
The total thickness of the laminate was measured with a snap gauge (“Thickness Gauge” manufactured by Mitutoyo Co., Ltd.). Further, the thicknesses of the first resin layer, the second resin layer and the third resin layer of the laminated body were read from the image of the cross section by observing the cross section of the laminated body with an optical microscope.

(Light transmittance of laminated body)
The light transmittance of the laminate at a wavelength of 380 nm to 780 nm was measured using an ultraviolet-visible near-infrared spectrophotometer (“V-7200” manufactured by JASCO Corporation). The data acquisition interval at the time of measurement was 1 nm. From the obtained spectrum, the light transmittance at wavelengths of 390 nm, 400 nm and 420 nm was read.

(B ^* value)
^{The value of b *} in the L ^* a ^* b ^* color system of the laminate was measured using a colorimetric color difference meter (“ZE6000” manufactured by Nippon Denshoku Industries Co., Ltd.). The measurement was performed using a C light source in a transmission mode and a viewing angle of 2 °.

(In-plane retardation of laminated body)
For the laminate, in-plane retardation at a measurement wavelength of 590 nm was measured using "AxoScan" manufactured by Axometrics.

(Suppression of deterioration of circularly polarizing plate: maximum rate of change of in-plane retardation ratio)
The laminate was bonded to a circularly polarizing element (a layer made of a cured product of a cholesteric liquid crystal composition) using a polyvinyl alcohol-based pressure-sensitive adhesive to obtain a circularly polarizing plate, and the in-plane retardation ratio of the circularly polarizing plate was obtained. (Re (450) / Re (550)) was measured. Here, Re (450) is an in-plane retardation (nm) at a measurement wavelength of 450 nm, and Re (550) is an in-plane retardation (nm) at a measurement wavelength of 550 nm. The in-plane retardation was measured using "AxoScan" manufactured by Axometrics.
A circularly polarizing plate was installed in a spectroscopic aging tester (“SPX” manufactured by Suga Test Instruments Co., Ltd.) so that light was incident from the side of the laminate. A spectroscopic aging test was carried out on the circularly polarizing plate by irradiating the circularly polarizing plate with light at 40 ° C. and 100 W for 24 hours. In the spectroscopic aging test, the light to be irradiated was separated at intervals of 2 nm, and the wavelength range of the light to be irradiated was set to 250 nm to 420 nm. The light of each of these dispersed wavelengths was irradiated to different locations on the circularly polarizing plate.

For the circularly polarizing plate after the spectroscopic aging test, the in-plane retardation ratio (Re (450) / Re (550)) corresponding to the irradiated light of each wavelength was measured. The measurement was carried out using "AxoScan" manufactured by Axometrics as before the spectroscopic aging test.
The in-plane retardation ratio of the circularly polarizing plate before the spectroscopic aging test is 100%, and the in-plane retardation ratio of the circularly polarizing plate after the spectroscopic aging test is X%. ) / Re (550) was measured. The absolute value of the rate of change is given by | X-100 | (%). The absolute value of the rate of change corresponding to the light of each irradiated wavelength was obtained, and the maximum value among the absolute values of the rate of change obtained in the range of the irradiated wavelengths of 250 nm to 420 nm was set as the maximum change for the circularly polarizing plate. It was a rate. The smaller the maximum rate of change, the more the deterioration of the circularly polarizing plate is suppressed.
From the maximum rate of change, the suppression of deterioration of the circularly polarizing plate was evaluated according to the following criteria.
A: The maximum rate of change is less than 3%.
B: The maximum rate of change is 3% or more and less than 5%.
C: The maximum rate of change is 5% or more.

(Energy saving performance)
Assuming a case where the laminate is combined with an organic EL image display device, the energy saving performance (power consumption reduction performance) of the laminate was evaluated by the following method.
The light transmittance of the laminate at a wavelength of 380 nm to 780 nm was measured using an ultraviolet-visible near-infrared spectrophotometer (“V-7200” manufactured by JASCO Corporation). The data acquisition interval at the time of measurement was 1 nm. From the obtained spectrum, the light transmittance at a wavelength of 420 nm to 500 nm was read, and the average value of the light transmittance at a wavelength of 420 nm to 500 nm was obtained. From the average value of the light transmittance, the energy saving performance of the laminated body was evaluated according to the following criteria. The larger the average value of the light transmittance, the higher the energy saving performance of the laminated body.
Good: The average value of light transmittance is 90% or more.
Defective: The average value of light transmittance is less than 90%.

[Production Example UV1] Production of UV absorber (a) 2- (2-Hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole (5.00 g, 15.8 mmol), octanethiol ( 7.63 g, 52.1 mmol), potassium carbonate (7.20 g, 52.1 mmol) and potassium iodide (0.18 g, 1.1 mmol) were reacted in 50 mL of DMF at 150 ° C. for 20 hours. After completion of the reaction, toluene was added, the organic layer was washed with water, the solvent was distilled off, and the residue was purified by column chromatography to obtain an ultraviolet absorber (a). The ultraviolet absorber (a) is a compound having a benzotriazole ring and a sulfur atom, and is a compound in which R ¹ is an octyl group in the compound represented by the above formula (i). When the ultraviolet absorption spectrum of the ultraviolet absorber (a) was measured with a spectrophotometer in a wavelength range of 250 nm or more and 800 nm or less, the maximum maximum absorption wavelength was 368 nm. The measurement was carried out by dissolving the ultraviolet absorber (a) in toluene to prepare a 10 mg / L solution, and placing the solution in a quartz cell having an optical path length of 10 mm.

[Production Example 1] Production of Resin J1 Resin 1 (“ZEONOR” manufactured by Nippon Zeon Co., Ltd .: glass transition temperature = about 126 ° C.) was prepared as a resin containing a polymer containing an alicyclic structure.
92 parts by weight of the resin 1 and 8 parts by weight of the ultraviolet absorber (a) were mixed by a twin-screw kneader. Then, the obtained mixture was supplied to a uniaxial extruder and melt-extruded to obtain resin J1. The proportion of the ultraviolet absorber (a) in the resin J1 is 8% by weight.

[Production Example 2] Production of Resin J2 Resin 2 (“ZEONOR” manufactured by Nippon Zeon Co., Ltd .: glass transition temperature = about 138 ° C.) was prepared as a resin containing a polymer containing an alicyclic structure.
87 parts by weight of the resin 2 and 13 parts by weight of the ultraviolet absorber (a) were mixed by a twin-screw kneader. Then, the obtained mixture was supplied to a single-screw extruder and melt-extruded to obtain resin J2. The proportion of the ultraviolet absorber (a) in the resin J2 is 13% by weight.

[Production Example 3] Production of Resin J3 Resin J3 was obtained in the same manner as in Production Example 1 except that the following items were changed.
The amount of the resin 1 was changed from 92 parts by weight to 94 parts by weight, and the amount of the ultraviolet absorber (a) was changed from 8 parts by weight to 6 parts by weight.
The proportion of the ultraviolet absorber (a) in the resin J3 is 6% by weight.

[Production Example 4] Production of Resin J4 Resin J4 was obtained in the same manner as in Production Example 1 except that the following items were changed.
-The amount of resin 1 was changed from 92 parts by weight to 84 parts by weight.
16 parts by weight of the ultraviolet absorber (b) was used instead of 8 parts by weight of the ultraviolet absorber (a).
The ultraviolet absorber (b) is a triazine-based ultraviolet absorber (“ADEKA STUB LA-F70” manufactured by ADEKA Corporation). The proportion of the ultraviolet absorber (b) in the resin J4 is 16% by weight.

[Production Example 5] Production of Resin J5 Resin J5 was obtained in the same manner as in Production Example 1 except that the following items were changed.
-The amount of resin 1 was changed from 92 parts by weight to 77 parts by weight.
-Instead of 8 parts by weight of the ultraviolet absorber (a), 23 parts by weight of the ultraviolet absorber (c) was used.
The ultraviolet absorber (c) is a benzotriazole-based ultraviolet absorber (“ADEKA STAB LA-31RG” manufactured by ADEKA Corporation). The proportion of the ultraviolet absorber (c) in the resin J5 is 23% by weight.

[Example 1]
(Coextrusion molding process)
A T-die type film melt extrusion molding machine (stationary type, manufactured by GSI Creos Corporation) was prepared. The film melt extrusion molding machine is equipped with three screw extruders, and each screw extruder has a screw diameter of 20 mmφ, a compression ratio of 3.1, and a ratio L / D of the effective screw length L and the screw diameter D. Was 30. The T-die was a hanger manu-hold type with three layers for coextrusion.

Resin 1 and resin J1 were supplied to a film melt extrusion molding machine and coextruded to obtain a molded product 1 having a two-kind three-layer structure. The molded body 1 has a layer structure of (layer of resin 1) / (layer of resin J1) / (layer of resin 1). The conditions for coextrusion molding were as follows.
・ Die lip: 0.8mm
・ T-die width: 600mm
-Resin temperature: 260 ° C
-Cooling roll temperature: 100 ° C
-The extrusion speed of the screw extruder was adjusted so that each layer of the laminated body obtained by stretching the molded body had the thickness shown in the table.
The obtained long molded body 1 was wound into a roll.

(Stretching process)
Next, a tenter stretching machine equipped with a clip was prepared. The molded body 1 was stretched by holding both ends (two sides) of the molded body 1 in the width direction with a clip and pulling the molded body 1 in an oblique direction at 45 degrees with respect to the width direction. The stretching conditions were a stretching temperature of 120 ° C. and a stretching ratio of 2.4 times. As a result, the laminated body 1 was obtained. The thickness of each layer included in the laminate 1 is (resin 1 layer) / (resin J1 layer) / (resin 1 layer) = 3 μm / 14 μm / 3 μm, and the total thickness of the laminate 1 is 20 μm. It was.
The laminated body 1 was evaluated by the above method.

[Example 2]
(Coextrusion molding process)
A molded product 2 having a two-kind three-layer structure was obtained in the same manner as in the coextrusion molding step of Example 1 except that the following items were changed.
-Resin J2 was supplied to the film melt extrusion molding machine instead of the resin J1.
-The resin temperature was set to 270 ° C.
-The extrusion speed of the screw extruder was adjusted so that each layer of the laminated body obtained by stretching the molded body had the thickness shown in the table.
The molded body 2 has a layer structure of (resin 1 layer) / (resin J2 layer) / (resin 1 layer).

(Stretching process)
A laminated body 2 was obtained in the same manner as in the stretching step of Example 1 except that the following items were changed.
-The molded body 2 was used instead of the molded body 1.
-The stretching conditions were changed to a stretching temperature of 125 ° C. and a stretching ratio of 2.2 times.
The thickness of each layer included in the laminate 2 was (resin 1 layer) / (resin J2 layer) / (resin 1 layer) = 6 μm / 9 μm / 6 μm, and the total thickness of the laminate 2 was 21 μm. ..
The laminated body 2 was evaluated by the above method.

[Example 3]
(Coextrusion molding process)
As a film melt extrusion molding machine, a T-die type film melt extrusion molding machine (stationary type, manufactured by GSI Creos Corporation) equipped with two screw extruders was prepared. Each screw extruder had the same screw diameter, compression ratio, and ratio L / D as the extruder provided in the film melt extrusion molding machine used in Example 1. The T-die was a two-layer hanger manipulation type for coextrusion.

Resin 1 and resin J3 were supplied to a film melt extrusion molding machine and coextruded to obtain a molded product 3 having a two-kind two-layer structure. The molded body 3 has a layer structure of (layer of resin 1) / (layer of resin J3). The conditions for coextrusion molding were as follows.
・ Die lip: 0.8mm
・ T-die width: 600 mm,
-Resin temperature: 260 ° C
-Cooling roll temperature: 100 ° C
-The extrusion speed of the screw extruder was adjusted so that each layer of the laminated body obtained by stretching the molded body had the thickness shown in the table.
The obtained long molded body 1 was wound into a roll.

(Stretching process)
A laminated body 3 was obtained in the same manner as in the stretching step of Example 1 except that the following items were changed.
-A molded body 3 was used instead of the molded body 1.
The thickness of each layer included in the laminated body 3 was (layer of resin 1) / (layer of resin J3) = 3 μm / 14 μm, and the total thickness of the laminated body was 17 μm.
The laminated body 3 was evaluated by the above method.

[Comparative Example 1]
(Coextrusion molding process)
A molded product C1 having a two-kind two-layer structure was obtained in the same manner as in the coextrusion molding step of Example 1 except for the following items.
-Resin J4 was supplied to the film melt extrusion molding machine instead of the resin J1.
-The extrusion speed of the screw extruder was adjusted so that each layer of the laminated body obtained by stretching the molded body had the thickness shown in the table.
The molded product C1 has a layer structure of (resin 1 layer) / (resin J4 layer) / (resin 1 layer).

(Stretching process)
A laminated body C1 was obtained in the same manner as in the stretching step of Example 1 except that the following items were changed.
-A molded body C1 was used instead of the molded body 1.
-The stretching conditions were changed to a stretching temperature of 120 ° C. and a stretching ratio of 2.0 times.
The thickness of each layer included in the laminate C1 was (resin 1 layer) / (resin J4 layer) / (resin 1 layer) = 4 μm / 18 μm / 4 μm, and the total thickness of the laminate was 26 μm. ..
The laminated body C1 was evaluated by the above method.

[Comparative Example 2]
(Coextrusion molding process)
A molded product C2 having a two-kind three-layer structure was obtained in the same manner as in the coextrusion molding step of Example 1 except that the following items were changed.
-Resin J5 was supplied to the film melt extrusion molding machine instead of the resin J1.
-The extrusion speed of the screw extruder was adjusted so that each layer of the laminated body obtained by stretching the molded body had the thickness shown in the table.
The molded body C2 has a layer structure of (resin 1 layer) / (resin J5 layer) / (resin 1 layer).

(Stretching process)
A laminated body C2 was obtained in the same manner as in the stretching step of Example 1 except that the following items were changed.
-A molded body C2 was used instead of the molded body 1.
-The stretching conditions were changed to a stretching temperature of 120 ° C. and a stretching ratio of 3.0 times.
The thickness of each layer included in the laminate C2 was (resin 1 layer) / (resin J5 layer) / (resin 1 layer) = 3 μm / 21 μm / 3 μm, and the total thickness of the laminate was 27 μm. ..
The laminated body C2 was evaluated by the above method.

[result]
The results of Examples and Comparative Examples are shown in the table below.
In the table below, the abbreviations have the following meanings.
"Resin 1": "ZEONOR" manufactured by Zeon Corporation: Glass transition temperature = approx. 126 ° C
"Resin 2": "ZEONOR" manufactured by Zeon Corporation: Glass transition temperature = approx. 138 ° C
"Resin J1" to "Resin J5": Resins produced in Production Examples 1 to 5, respectively "COP resin": Resin containing a polymer containing an alicyclic structure
"UVA": UV absorber "a": UV absorber (a)
"LA-F70": "ADEKA STAB LA-F70" manufactured by ADEKA
"LA-31": "ADEKA STAB LA-31RG" manufactured by ADEKA
"Re": In-plane retardation "Deterioration suppression": Deterioration suppression of circularly polarizing plate

From the above results, the following matters can be understood.
The laminates of Comparative Examples 1 and 2 that do not satisfy any of the conditions (1) to (3) are compared with the laminates of Examples 1 to 3 that satisfy all of the conditions (1) to (3). It is inferior in deterioration suppressing characteristics of circularly polarizing plates. Here, the conditions (1) to (3) are as follows.
(1) The light transmittance at a wavelength of 390 nm is 0.1% or less.
(2) The light transmittance at a wavelength of 400 nm is 5% or less.
(3) The light transmittance at a wavelength of 420 nm is 80% or more.

Further, in the laminated body of Comparative Example 2, b ^* is smaller than 0.7 and the energy saving performance is good, but the deterioration suppressing property of the circularly polarizing plate is significantly inferior to that of the Example.

On the other hand, the laminate of the examples satisfying all the conditions (1) to (3) is excellent in the deterioration suppressing property of the circularly polarizing plate, and b ^* is 2.0 or less, which is sufficient for practical use. Therefore, in the laminate of the present invention, the thickness of the first resin layer containing the ultraviolet absorber is thin, and while the thickness is 20 μm or less, the protection of the circularly polarizing plate from ultraviolet rays and the suppression of yellow coloring are realized in a well-balanced manner. I know I can do it.

100 Laminated body 101 First resin layer 101U surface 102 Second resin layer 200 Laminated body 201 First resin layer 201U surface 201D surface 202 Second resin layer 203 Third resin layer 1000 Circularly polarizing plate 1001 Circular polarizing element

Claims (8)

A first resin layer made of a thermoplastic resin A containing a polymer containing an alicyclic structure and an ultraviolet absorber, and
A second resin layer made of a thermoplastic resin B1 containing a polymer containing an alicyclic structure is included.
The light transmittance at a wavelength of 390 nm is 0.1% or less, the light transmittance at a wavelength of 400 nm is 5% or less, and the light transmittance at a wavelength of 420 nm is 80% or more.
A laminate having a thickness of 20 μm or less of the first resin layer. The laminate according to claim 1, wherein the value of b ^{* in} the L ^* a ^* b ^{* color system is 0.7 or more and 2.0 or less.} The laminate according to claim 1 or 2, wherein the thermoplastic resin A contains a compound I having a benzotriazole ring and a sulfur atom. The laminate according to claim 3, wherein the compound I is a compound represented by the following formula (i).

(In the formula, R ¹ represents an alkyl group, a cycloalkyl group, an alkylthioalkyl group, an alkenyl group, an aryl group, or an arylalkyl group.) The laminate according to claim 4, wherein R ^{1 is an alkyl group.} Claims 1 to 5, wherein the laminate is a long laminate, the in-plane retardation is 70 nm or more and less than 150 nm, and the angle between the slow axis and the longitudinal direction is in the range of 45 ° ± 5 °. The laminate according to any one item. A third resin layer made of a thermoplastic resin B2 containing a polymer containing an alicyclic structure is further contained, and the second resin layer is provided on one surface of the first resin layer, and the first resin layer is provided. The laminate according to any one of claims 1 to 6, wherein the third resin layer is provided on the other surface of the above. A circularly polarizing plate containing the laminate according to any one of claims 1 to 7 and a circularly polarizing element.

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