JP2021092770A - Laminate and optical laminate - Google Patents

Abstract

To provide an optical laminate that prevents cracking caused by a sudden temperature change, and an optical laminate and a laminate that prevent the peeling between laminated liquid crystal cured layers.SOLUTION: A laminate 100 has a first substrate layer 111, a first liquid crystal cured layer 121, a tacky adhesive layer 15, a second liquid crystal cured layer 122 and a second substrate layer 112 in the stated order. Both the first liquid crystal cured layer and the second liquid crystal cured layer include a layer including a cured product of a polymerizable liquid crystal compound and an alignment layer. The first liquid crystal cured layer and the second liquid crystal cured layer each have an elastic modulus of piercing of 50 g/mm or less, calculated by predetermined conditions. Out of the first substrate layer and the second substrate layer, first peeled one is regarded as a first peeling layer and the later peeled substrate layer is regarded as a second peeling layer, and the peeling force when peeling the first peeling layer is greater than that when peeling the second peeling layer. An optical laminate obtained by peeling the first substrate layer and the second substrate layer from the laminate has a tensile elasticity of 1,000 N/mm2 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate and an optical laminate.

In recent years, image display devices typified by organic electroluminescence (hereinafter, also referred to as organic EL) display devices have rapidly become widespread. The organic EL display device is equipped with a circularly polarizing plate including a polarizer and a retardation film, and an optical laminate on which other optical functional layers are laminated.

As a retardation film for an image display device such as an organic EL display device, a film obtained by stretching a conventional resin film or a film formed of a liquid crystal compound as a material has been studied. As the demand for thinner image display devices grows stronger, the retardation film and the optical laminate provided with the retardation film are also required to be thinner (see, for example, Patent Document 1).

JP-A-2017-102286

Conventionally known optical laminates containing a retardation film may have cracks starting from the retardation film due to expansion and contraction due to a temperature change. Such cracks are likely to occur particularly when a sudden temperature change (thermal shock) is applied. If the cracks are likely to occur, the durability of the optical laminate may be lowered, and the visibility in the image display device may also be lowered.

Further, for an optical laminate in which two or more liquid crystal cured layers such as a retardation layer are laminated, a laminate in which base material layers are laminated on both sides of the optical laminate is manufactured in the manufacturing process, and the laminate is manufactured. It is often manufactured through a step of peeling the base material layers on both sides. In the above peeling step, an external force is applied between two or more laminated liquid crystal curing layers, so that a slight peeling occurs between the liquid crystal curing layers. May occur. Such peeling may also reduce visibility when the optical laminate is incorporated into an image display device.

Therefore, an object of the present invention is to provide an optical laminate in which the occurrence of cracks due to a sudden temperature change is suppressed. Another object of the present invention is to provide an optical laminate and a laminate in which peeling between the laminated liquid crystal curing layers is unlikely to occur due to an external force such as peeling of the base material layer laminated on the optical laminate. To do.

In order to solve the above problems, the present inventors have studied the configurations of the liquid crystal cured layer and the optical laminate in the optical laminate. As a result, they have found that the above problems are achieved when the film forming the liquid crystal cured layer has a predetermined piercing elastic modulus and the optical laminate has a predetermined tensile elastic modulus, and completes the present invention. I came to let you.

That is, the present invention includes the following preferred embodiments.
[1] A laminate containing a first base material layer, a first liquid crystal cured layer, an adhesive layer, a second liquid crystal cured layer, and a second base material layer in this order.
Both the first liquid crystal cured layer and the second liquid crystal cured layer include a layer containing a cured product of a polymerizable liquid crystal compound and an orientation layer.
Each of the first liquid crystal cured layer and the second liquid crystal cured layer uses a measurement sample in which a film forming the layer is bonded to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and has a tip diameter. A needle of 1 mm φ0.5 R is pierced perpendicularly to the surface of the film at a speed of 0.33 cm / sec, and the amount of displacement due to bending of the film in the piercing direction, which is measured when a break occurs, is the amount of strain. When S (mm) and the stress applied to the film are F (g), the formula (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
The puncture elastic modulus calculated by
The first base material layer and the second base material layer can be peeled off from the first liquid crystal cured layer and the second liquid crystal cured layer, respectively, and among the first base material layer and the second base material layer, When the base material layer to be peeled off first is the first peeling layer and the base material layer to be peeled off later is the second peeling layer, the peeling force when peeling the first peeling layer is to peel off the second peeling layer. Greater than the peeling force when
The thickness of the alignment layer contained in the first liquid crystal cured layer is smaller than the thickness of the alignment layer contained in the second liquid crystal cured layer.
^{A laminate having a tensile elastic modulus of 1,000 N / mm 2} or less, which is obtained by peeling the first base material layer and the second base material layer from the laminate.
[2] The peeling force when peeling the first peeling layer is 0.15 N / 25 mm or less, and the peeling force when peeling the second peeling layer is 0.05 N / 25 mm or more. ] The laminated body described in.
[3] The thickness of the alignment layer contained in the first liquid crystal cured layer is 1/3 or less of the thickness of the alignment layer contained in the second liquid crystal alignment layer, according to the above [1] or [2]. The laminate according to any one.
[4] The thickness of the alignment layer contained in the first liquid crystal curing layer is 10 nm to 500 nm, and the thickness of the alignment layer contained in the second liquid crystal alignment layer is 1 μm to 3.5 μm. ] To [3].
[5] The first liquid crystal cured layer and the second liquid crystal cured layer are a layer giving a phase difference of λ / 4 and a positive C layer, or a layer giving a phase difference of λ / 4 and λ / 2. The laminate according to any one of [1] to [4] above, which is a layer that gives a phase difference of.
[6] The laminate according to any one of [1] to [5] above, wherein the adhesive layer is an adhesive layer.
[7] An optical laminate containing a first liquid crystal cured layer, an adhesive layer, and a second liquid crystal cured layer in this order.
Both the first liquid crystal cured layer and the second liquid crystal cured layer include a layer containing a cured product of a polymerizable liquid crystal compound and an orientation layer.
Each of the first liquid crystal cured layer and the second liquid crystal cured layer uses a measurement sample in which a film forming the layer is bonded to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and has a tip diameter. A needle of 1 mm φ0.5 R is pierced perpendicularly to the surface of the film at a speed of 0.33 cm / sec, and the amount of displacement due to bending of the film in the piercing direction, which is measured when a break occurs, is the amount of strain. When S (mm) and the stress applied to the film are F (g), the formula (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
The puncture elastic modulus calculated by
The thickness of the alignment layer contained in the first liquid crystal cured layer is smaller than the thickness of the alignment layer contained in the second liquid crystal cured layer.
An optical laminate having a tensile elastic modulus of 1,000 N / mm ² or less.
[8] The optical lamination according to the above [7], wherein the thickness of the alignment layer contained in the first liquid crystal curing layer is 1/3 or less of the thickness of the alignment layer contained in the second liquid crystal alignment layer. body.
[9] The thickness of the alignment layer contained in the first liquid crystal curing layer is 10 nm to 500 nm, and the thickness of the alignment layer contained in the second liquid crystal alignment layer is 1 μm to 3.5 μm. ] Or [8].

According to the present invention, it is possible to provide an optical laminate in which the occurrence of cracks due to a sudden temperature change is suppressed and peeling between the laminated liquid crystal curing layers is unlikely to occur.

It is sectional drawing which shows an example of the laminated body of this invention. It is a schematic view of the glued mount (hereinafter, sometimes referred to as "glued mount") having a void portion used for the measurement of the puncture elastic modulus, viewed from the upper surface. (A) is a schematic perspective view showing a main part when the measurement film is attached to the glued mount, and (b) is a diagram schematically showing the upper part after the measurement film is attached to the glued mount. Is. It is a figure which shows typically the cross section at the time of piercing a needle into a sample (hereinafter, sometimes referred to as a "mounting paper with a measuring film") after sticking a measuring film on a glued mount. It is a figure which shows typically the cross section at the time of piercing elastic modulus measurement, and (a) and (b) show the state which the film is deformed by piercing a needle into a film. It is a figure for demonstrating the measurement sample used for measuring the tensile elastic modulus of an optical laminate.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

<Laminate and optical laminate>
The optical laminate of the present invention contains a first liquid crystal cured layer, an adhesive layer and a second liquid crystal cured layer in this order, and the laminate of the present invention includes a first base material layer, a first liquid crystal cured layer, and a viscous layer. The adhesive layer, the second liquid crystal cured layer, and the second base material layer are included in this order. The optical laminate and the laminate of the present invention may contain additional layers other than the above as long as the above layers are included in the above order. Both the optical laminate and the first liquid crystal cured layer and the second liquid crystal cured layer contained in the laminate have a layer containing a cured product of a polymerizable liquid crystal compound and an orientation layer.

The first liquid crystal cured layer and the second liquid crystal cured layer contained in the laminated body and the optical laminated body of the present invention are layers in which an orientation layer and a layer containing a cured product of a polymerizable liquid crystal compound are laminated. The polymerizable liquid crystal compound is a compound having a polymerizable group and can be in a liquid crystal state. The polymerizable groups of the polymerizable liquid crystal compound react with each other to polymerize the polymerizable liquid crystal compound, so that the polymerizable liquid crystal compound is cured and each liquid crystal cured layer is formed. The cured product obtained by polymerizing the polymerizable liquid crystal compound does not need to exhibit liquid crystallinity.

The first liquid crystal cured layer and the second liquid crystal cured layer are preferably retardation layers, and more preferably, they independently give a phase difference of λ / 4, a layer giving a phase difference of λ / 2, and a layer. It is a layer selected from the group consisting of positive C layers. The first liquid crystal cured layer and the second liquid crystal cured layer are a combination of a layer giving a phase difference of λ / 4 and a positive C layer, or a layer giving a phase difference of λ / 4 and a layer giving a phase difference of λ / 2. It is preferable to use a combination of.

Each of the first liquid crystal cured layer and the second liquid crystal cured layer uses a measurement sample in which a film forming the layer is bonded to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and has a tip diameter of 1 mm φ0. The amount of displacement due to the deflection of the film in the piercing direction, which is measured when a 5R needle is pierced perpendicularly to the surface of the film at a speed of 0.33 cm / sec and a break occurs, is the amount of strain S. When (mm) and the stress applied to the film is F (g), the formula (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
The puncture elastic modulus calculated by the above is 50 g / mm or less. In the present specification, the first liquid crystal cured layer and the second liquid crystal cured layer are also simply referred to as "liquid crystal cured layer". When the puncture elastic modulus of each liquid crystal cured layer calculated by the above formula (1) is 50 g / mm or less, the occurrence of cracks due to a sudden temperature change can be suppressed. In the laminated body and the optical laminated body, when the puncture elastic modulus of the liquid crystal cured layer exceeds 50 g / mm, it is difficult to suppress the occurrence of cracks in the layer due to a sudden temperature change, and such an optical laminated body. When incorporating the above into an image display device, the durability of the optical laminate may not be sufficient and the visibility may be impaired.

The puncture elastic modulus of the liquid crystal cured layer is preferably 40 g / mm or less, more preferably 35 g / mm or less, still more preferably 30 g / mm, from the viewpoint of easily suppressing the occurrence of cracks due to a sudden temperature change in the optical laminate. It is as follows. Further, from the viewpoint of improving the peelability when peeling the base material layer and from the viewpoint of easily increasing the strength of the optical laminate, it is preferably 5 g / mm or more, more preferably 10 g / mm or more, still more preferably 15 g. / Mm or more.

In the present specification, the puncture elastic modulus uses a measurement sample in which a film is attached to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and a needle having a tip diameter of 1 mm φ0.5 R is 0.33 cm /. The amount of displacement due to bending of the film in the piercing direction, which is measured when the film is pierced perpendicularly to the surface of the film at a speed of seconds and breaks, is defined as the amount of strain S (mm) and added to the film. When the stress obtained is F (g), the proportional constant (stress F / strain S) between the stress F and the strain S is the equation (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
It is a physical characteristic value calculated by. The puncture elastic modulus can be measured using a compression tester equipped with a load cell. Examples of the compression tester include the puncture tester "NDG5" manufactured by Kato Tech Co., Ltd. and the handy compression tester "NDG5". Examples include "KES-G5" and "EZ Test", a small desktop testing machine manufactured by Shimadzu Corporation. From the stress-strain curve obtained by using such a compression tester, it is possible to measure the stress applied to the film when fracture occurs and the amount of strain generated in the film up to that point. The breakage that occurs in the film when the piercing jig is pressed includes the case where the film has a through hole due to the tip of the jig. Specifically, as described in the examples, the puncture elastic modulus is measured by using a measurement sample in which a film is attached to a glued mount having a gap portion cut out in a square having a central portion of 30 mm × 30 mm. A needle with a tip diameter of 1 mm φ0.5 R is pierced substantially perpendicular to the surface of the film at a speed of 0.33 cm / sec into the substantially center of the film in the gap, and is measured when a break occurs. The amount of displacement due to the deflection of the film in the piercing direction is calculated by the above formula (1) from the strain amount S (mm) and the stress F (g) applied to the film.

The main part of the measuring means of the puncture elastic modulus when the piercing tester "NDG5" manufactured by Kato Tech Co., Ltd. is used will be described with reference to the drawings.

FIG. 2 is a schematic view of a glued mount (glued mount 7) having a gap portion for determining the puncture elastic modulus of the liquid crystal cured layer as viewed from above. The glued mount 7 has a portion (void portion) hollowed out in a 30 mm × 30 mm square, which is a portion to which a film to be measured (liquid crystal cured layer, hereinafter also referred to as “measurement film 12”) is attached to the central portion. 6).

FIG. 3 is a schematic view showing a main part when the measuring film 12 is attached to the glued mount 7, and FIG. 3A is a perspective view when the measuring film 12 is attached to the glued mount 7. It is a schematic view which looked at the mount 1 with a measuring film after sticking the measuring film 12 to the attached mount 7 from the upper part (direction A of FIG. 3A). The dotted line indicates the outer circumference 8 of the gap portion 6. The position M at which the needle N is pierced, which is located substantially at the center of the gap portion 6, is an intersection of two straight lines connecting points (R and R') facing diagonally in the outer circumference 8 of the gap portion 6. FIG. 4 schematically shows a cross-sectional view (before piercing the needle N) along I-I'on the mount 1 with a measuring film.

The needle N is pierced substantially in the center of the measurement film 12 of aspect 1. In such piercing, the stress F (g) applied to the needle N is correlated with the strain amount S (mm) due to the deflection in the piercing direction of the film, and the stress F (g) and the strain when the film breaks occur. From the amount S (mm), the puncture elastic modulus is obtained according to the above formula (1). When determining the puncture elasticity, when the film is broken when it is deformed (when it is broken in the state shown in FIG. 5A), when the film is further deformed when it is broken. Although there is a case (when fracture occurs in the state of FIG. 5B), the puncture elasticity in the present invention is determined from the applied stress in the puncture tester and the strain amount S, and the strain amount S is defined as the strain amount S. , S may be the case where the break occurs in the state of FIG. 5 (a), or S may be the case where the break occurs in the state of FIG. 5 (b). Since the applied stress changes from an increasing tendency to a decreasing tendency due to the fracture of the film, it can be understood that the fracture occurred at this change.

The means for producing the mount 1 with the measurement film is not particularly limited. After the liquid crystal cured film with a base material having a specific size is attached to the gap 6 of the glued mount 7, the base material is peeled off from the attached liquid crystal cured film with a base material to obtain the mount 1 with a measurement film. It may be prepared, or the base material may be peeled from the liquid crystal cured film with a base material and the liquid crystal cured film after the peeling may be attached before being attached to the glued mount 7.

In the glued mount 7, the glue for fixing the measurement film is particularly limited as long as it can prevent the measurement film from peeling off even partially from the mount with the measurement film during the puncture elastic modulus measurement. Not done. An appropriate preliminary experiment may be performed to find the glue of the glued mount 7 used for measuring the puncture elastic modulus.

The thicknesses of the first liquid crystal cured layer and the second liquid crystal cured layer are not particularly limited, but are preferably 0.5 μm or more, more preferably 0.5 μm or more, respectively, from the viewpoint of sufficiently increasing the durability of the laminated body and the optical laminated body. It is 1.0 μm or more, more preferably 2.0 μm or more. Further, the thickness is preferably 10 μm or less, more preferably 5 μm or less, still more preferably 3.5 μm or less, from the viewpoint that the laminated body and the optical laminated body can be easily thinned and the visibility can be easily improved. The above-mentioned upper limit value and lower limit value can be arbitrarily combined. The thickness of the liquid crystal cured layer can be measured using a laser microscope.

In the liquid crystal cured layer such as the first liquid crystal cured layer and the second liquid crystal cured layer, as described later, for example, a composition containing a polymerizable liquid crystal compound is applied onto an appropriate substrate to contain the polymerizable liquid crystal compound. It can be formed by forming a coating layer on a substrate and polymerizing a polymerizable liquid crystal compound contained in the coating layer. A liquid crystal cured layer having a desired thickness can be produced by the thickness controlling means of the coated layer according to the coating means of the liquid crystal cured layer. An appropriate preliminary experiment may be performed in order to obtain the correlation between the thickness of the coating layer and the thickness of the obtained liquid crystal cured layer.

In the laminate of the present invention, the first base material layer and the second base material layer can be peeled off from the first liquid crystal cured layer and the second liquid crystal cured layer, respectively, and the first base material layer and the first base material layer can be separated from the laminate. The tensile elastic modulus of the optical laminate obtained by peeling the second base material layer is 1,000 N / mm ² or less. When the tensile elastic modulus of ^{the optical laminate exceeds 1,000 N / mm 2} , peeling between the laminated liquid crystal curing layers caused by external force such as peeling of the base material layer laminated on the optical laminate is sufficiently suppressed. Can't. Tensile elastic modulus of the optical stack, from the viewpoint of easily preventing separation of the liquid crystal cured layer, preferably 980 N / mm ² or less, more preferably 900 N / mm ² or less. The tensile elastic modulus of the optical laminate is preferably 400 N / mm ² or more, more preferably 500 N / mm ² or more, and particularly the adhesive layer is an adhesive layer, from the viewpoint of easily preventing peeling between the liquid crystal curing layers. If it is, more preferably 600N / mm ² or more, even more preferably 700 N / mm ² or more, especially preferably 800 N / mm ² or more.

In the laminate of the present invention, of the first base material layer and the second base material layer, the base material layer to be peeled off first is the first peeling layer, and the base material layer to be peeled off later is the second peeling. As a layer, the peeling force when peeling the first peeling layer is preferably 0.15 N / 25 mm or less, more preferably 0.13 N / 25 mm or less, further preferably 0.13 N / 25 mm or less, from the viewpoint of easily preventing peeling between the liquid crystal curing layers. Is 0.10 N / 25 mm or less, and the peeling force when peeling the second peeling layer is preferably 0.05 N / 25 mm or more, more preferably 0, from the viewpoint of easily preventing peeling between the liquid crystal curing layers. .07N / 25mm or more. The peeling force can be measured using a tensile tester, for example, by the method described in Examples.

The optical laminate of the present invention is preferably a laminate obtained after peeling the first base material layer and the second base material layer from the laminate of the present invention.

The generation of cracks due to a sudden temperature change in the optical laminate tends to occur when the liquid crystal cured layer contains an oriented layer. According to the laminated body and the optical laminated body of the present invention, it is possible to suppress the occurrence of cracks due to a sudden temperature change even in the above case.

Further, in the peeling between the laminated liquid crystal curing layers, of the first base material layer and the second base material layer in the laminated body, the base material layer to be peeled off first is used as the first peeling layer and is peeled off later. When the base material layer is the second peeling layer and the peeling force when peeling the first peeling layer is larger than the peeling force when peeling the second peeling layer, the liquid crystal cured layer is bonded via the adhesive layer. It is likely to occur when it is done. According to the present invention, even in the above case, it is possible to suppress peeling between the laminated liquid crystal curing layers.

In the laminate of the present invention, when the base material layer to be peeled off first is the first peeling layer and the base material layer to be peeled off later is the second peeling layer, when the first peeling layer is peeled off. The peeling force is larger than the peeling force when peeling the second peeling layer. Even in this case, in the laminated body of the present invention, the effect of suppressing peeling between the laminated liquid crystal curing layers can be obtained.

The thickness of the laminate of the present invention is preferably 80 μm or more, more preferably 140 μm or more, because if it is too thin, the strength tends to decrease and the processability tends to be inferior. Further, the above-mentioned thickness is preferably 170 μm or less, more preferably 160 μm or less, from the viewpoint that when the length is increased, the weight becomes heavy and handling becomes difficult when the length is increased.

The thickness of the optical laminate of the present invention is preferably 3 μm or more, more preferably 5 μm or more, still more preferably 6 μm or more, from the viewpoint of easily thinning the optical laminate and enhancing visibility. The thickness is preferably 30 μm or less, more preferably 25 μm or less, still more preferably 15 μm or less.

<Liquid crystal cured layer>
The first liquid crystal cured layer and the second liquid crystal cured layer contained in the laminated body and the optical laminated body of the present invention are layers in which an orientation layer and a layer containing a cured product of a polymerizable liquid crystal compound are laminated.

(Polymerizable liquid crystal cured product-containing layer)
The first liquid crystal cured layer and the second liquid crystal cured layer contained in the laminate and the optical laminate of the present invention include at least a layer containing a cured product of the polymerizable liquid crystal compound (also referred to as a “polymerizable liquid crystal cured product-containing layer”). Including. The type of the polymerizable liquid crystal compound is not particularly limited, and when classified according to its shape, it may be either a rod-shaped type (rod-shaped liquid crystal compound) or a disk-shaped type (disk-shaped liquid crystal compound, discotic liquid crystal compound). Further, it may be either a low molecular weight type or a high molecular weight type in each classification. In addition, in this specification, a polymer means a polymer having a degree of polymerization of 100 or more. The polymerizable liquid crystal compound contained as a cured product in the liquid crystal cured layer may be one kind or a mixture of two or more kinds (for example, a mixture of two or more kinds of rod-shaped liquid crystal compounds and two or more kinds of disk-shaped liquid crystal compounds. It may be a mixture or a mixture of a rod-shaped liquid crystal compound and a disk-shaped liquid crystal compound).

As the rod-shaped liquid crystal compound, for example, the compound according to claim 1 of JP-A-11-513019 can be preferably used. As the disk-shaped liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013] to [0108] of JP-A-2010-244038 are preferable. Can be used for.

The polymerizable liquid crystal compound may be one kind or a combination of two or more kinds, but at least one kind of polymerizable liquid crystal compound preferably has two or more polymerizable groups in the molecule. ..

The polymerizable group contained in the polymerizable liquid crystal compound is not particularly limited, but is preferably a functional group capable of an addition polymerization reaction, more preferably an ethylenically unsaturated group and a ring-polymerizable group, and further preferably ethylenically. It is an unsaturated group. Examples of the ethylenically unsaturated group include a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group and the like. The polymerizable group is preferably a (meth) acryloyl group because it is easy to handle and easy to manufacture. The (meth) acryloyl group is a concept that includes both a meta-acryloyl group and an acryloyl group.

The liquid crystal cured layer is formed, for example, by forming an alignment layer on a base material layer described later and applying a composition containing a polymerizable liquid crystal compound on the alignment layer. The base material layer is usually used by peeling from the liquid crystal cured layer, but when peeled off, peeling occurs between the alignment layer and the base material layer, and the alignment layer is included in the optical laminate. Therefore, the first liquid crystal cured layer and the second liquid crystal cured layer include a layer containing a cured product of the polymerizable liquid crystal compound and an orientation layer. Further, in this case, the alignment layer contained in the first liquid crystal cured layer and the second liquid crystal cured layer is a transfer type alignment layer that is not peeled off together with the base material.

The thickness of the layer containing the cured product of the polymerizable liquid crystal compound is not particularly limited, but is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of sufficiently increasing the durability of the laminated body and the optical laminated body. More preferably, it is 2 μm or more. Further, the thickness is preferably 10 μm or less, more preferably 5 μm or less, still more preferably 4 μm or less, from the viewpoint that the laminated body and the optical laminated body can be easily thinned and the visibility can be easily improved. The above-mentioned upper limit value and lower limit value can be arbitrarily combined. In addition, the thickness of the layer containing the cured product of the polymerizable liquid crystal compound can be measured using a laser microscope. When the liquid crystal cured layer is a layer selected from the group consisting of a layer giving a phase difference of λ / 4, a layer giving a phase difference of λ / 2, and a positive C layer, a layer containing a cured product of a polymerizable liquid crystal compound. The thickness of the above may be adjusted so as to obtain a desired in-plane retardation value and a retardation value in the thickness direction.

(Orientation layer)
The oriented layer is a layer having an ability to regulate the direction of the molecular axis of the polymerizable liquid crystal compound forming the liquid crystal cured layer so as to have a desired retardation characteristic. The layer on which the polymerizable liquid crystal compound is cured (liquid crystal cured layer) is formed on the base material via the alignment layer. Examples of the alignment layer include an alignment layer containing an orientation polymer, a photoalignment film, and a grub alignment layer in which an uneven pattern or a plurality of grooves are formed and oriented on the surface.

After forming the liquid crystal cured layer on the oriented layer, the oriented layer is peeled off together with the base material layer when the base material layer is peeled from the laminate containing the liquid crystal cured layer, or remains in the liquid crystal cured layer. .. In the present invention, in order to include the alignment layer in the liquid crystal cured layer, the base material layer is peeled off so that the alignment layer remains in the liquid crystal cured layer. By leaving the oriented layer in the liquid crystal cured layer in this way, it is easy to adjust the puncture elastic modulus of the liquid crystal cured layer to the above-mentioned desired range, and it is easy to improve the peelability when peeling the base material layer. Therefore, from the same viewpoint, the first liquid crystal cured layer and the second liquid crystal cured layer are preferably layers in which an orientation layer and a layer containing a cured product of a polymerizable liquid crystal compound are laminated.

The alignment layer is monofunctional or bifunctional (meth) from the viewpoint that the alignment layer is not peeled off and removed together with the base material layer and is easily left in the liquid crystal cured layer, and the puncture elastic modulus is easily adjusted to a desired range. ) It is preferable to contain a resin such as a cured product obtained by curing an acrylate-based monomer, an imide-based monomer or a vinyl ether-based monomer, and more preferably a cured product obtained by curing a monofunctional or bifunctional (meth) acrylate-based monomer. preferable. If the oriented layer is not peeled off together with the base material layer and the liquid crystal cured layer contains the oriented layer, there is an advantage that the strength of the optical laminate can be easily maintained.

In the laminate or optical laminate of the present invention in which the liquid crystal curing layer contains an orientation layer, the preferred monofunctional (meth) acrylate-based monomer is, for example, an alkyl (meth) acrylate having 4 to 16 carbon atoms and 2 to 2 carbon atoms. Examples thereof include 14 β-carboxyalkyl (meth) acrylates, alkylated phenyl (meth) acrylates having 2 to 14 carbon atoms, methoxypolyethylene glycol (meth) acrylates, phenoxypolyethylene glycol (meth) acrylates and isobonyl (meth) acrylates. .. Examples of the bifunctional (meth) acrylate-based monomer include 1,3-butanediol di (meth) acrylate, 1,3-butanediol (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and ethylene glycol di. (Meta) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol diacrylate, bisphenol A bis (acrylate) Loyloxyethyl) ether, ethoxylated bisphenol A-di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, 3-methylpentanediol di (meth) acrylate, etc. Can be mentioned. Examples of the imide-based resin obtained by curing the imide-based monomer include polyamide and polyimide. The imide-based resin may be one of these types or a mixture of two or more types.

The resin contained in the alignment layer may contain a structural unit derived from a monomer other than a monofunctional or bifunctional (meth) acrylate-based monomer, an imide-based monomer, and a vinyl ether-based monomer. The content ratio of the structural units derived from the monofunctional or bifunctional (meth) acrylate-based monomer, imide-based monomer, and vinyl ether-based monomer is preferably 50 mol% or more, more preferably 55 mol%, based on all the structural units. Above, more preferably 60 mol% or more.

The thickness of the oriented layer is preferably 10 nm or more, more preferably 100 nm or more, still more preferably 500 nm or more, even more preferably 1,000 nm or more, and particularly preferably 2,000 nm or more. The thickness of the alignment layer is preferably 10,000 nm or less, more preferably 7,000 nm or less, and further preferably 5,000 nm or less. In particular, when the oriented layer is included in the liquid crystal cured layer, if the thickness of the oriented layer is within the above range, the puncture elastic modulus of the liquid crystal cured layer can be easily adjusted to the above preferred range.

As described above, when the base material layer to be peeled off first is the first peeling layer and the base material layer to be peeled off later is the second peeling layer, the peeling force when peeling the first peeling layer is the second. In order to exhibit the effect of suppressing peeling between the laminated liquid crystal curing layers even when the peeling force is larger than the peeling force at the time of peeling the peeling layer, the first liquid crystal curing layer and the second liquid crystal curing layer are exhibited. It is effective to make the thickness of the alignment layer contained in each of the above different. Specifically, when the first liquid crystal cured layer and the first release layer and the second liquid crystal cured layer and the second release layer are laminated, the thickness of the alignment layer contained in the first liquid crystal cured layer is the second. It is smaller than the thickness of the alignment layer contained in the liquid crystal alignment layer. In this way, by increasing the peel strength of the first peeling layer to be peeled first and reducing the thickness of the alignment layer contained in the first liquid crystal cured layer laminated on the first peeling layer, the thickness of the alignment layer is reduced. The reason why the effect of suppressing the generation of cracks due to thermal shock while having an appropriate peelability is not always clear, and is a result based on the findings of the present inventor.

As described above, the thickness of the alignment layer (hereinafter, also referred to as “first alignment layer”) contained in the first liquid crystal cured layer is preferably 10 nm to 500 nm, more preferably 50 nm to 200 nm. .. The thickness of the alignment layer (hereinafter, also referred to as “second alignment layer”) contained in the second liquid crystal cured layer is preferably 1 μm to 3.5 μm, and preferably 1.5 μm to 3.0 μm. More preferred. Such a combination of the thicknesses of the alignment layers improves the peelability while preventing the occurrence of cracks due to a sudden temperature change (that is, suppressing the peeling between the laminated liquid crystal curing layers, while suppressing the peeling between the laminated liquid crystal curing layers, and the base material layer It is effective for peeling off). Setting the thickness of the alignment layer contained in the first liquid crystal cured layer within the above range is effective in preventing the occurrence of cracks. On the other hand, since the second base material layer is peeled off after the first base material layer, the rigidity of the alignment layer contained in the second liquid crystal cured layer on the second base material layer tends to affect the peelability. Setting the thickness of the alignment layer contained in the second liquid crystal cured layer within the above range leads to an increase in the rigidity of the alignment layer and is effective in improving the peelability. The thickness of the first alignment layer and the second alignment layer is such that an alignment layer is formed on the substrate by applying a liquid composition called an alignment layer forming composition capable of forming these alignment layers onto the substrate. By adjusting the thickness of the coating film at the time of coating, it can be adjusted to a desired range. The alignment layer forming composition may be applied by, for example, a die coating means, and the thickness of the applied coating film determines the thickness of the oriented layer to be formed. Therefore, since the thickness of the alignment layer usually includes an error due to a thickness error of the coating means used, the coating used to make the thickness of the first alignment layer smaller than the thickness of the second alignment layer. It is necessary to consider the error of the means. When it is necessary to consider such an error, when measuring the thickness of the alignment layer, the thickness of the alignment layer is measured at at least 3 points or more, more preferably 5 points or more. It is preferable that the average value of the obtained results is the thickness of the alignment layer. In order to further enjoy the effects of the present invention, the thickness of the first alignment layer is preferably 1/3 or less, more preferably 1/5 or less, and 1/5 of the thickness of the second alignment layer. It is particularly preferable that it is 10 or less.

The alignment layer may be a vertically oriented layer in which the molecular axis of the polymerizable liquid crystal compound is vertically oriented, an oriented layer in which the molecular axis of the polymerizable liquid crystal compound is horizontally oriented, or the polymerizable liquid crystal compound. It may be an alignment layer in which the molecular axis of the compound is obliquely oriented. The alignment layer has solvent resistance that does not dissolve due to coating of a composition containing a polymerizable liquid crystal compound, which will be described later, and heat resistance in heat treatment for removing the solvent and aligning the liquid crystal compound. preferable. Examples of the alignment layer include an alignment layer containing an orientation polymer, a photoalignment film, and a grub alignment layer in which an uneven pattern or a plurality of grooves are formed and oriented on the surface.

The oriented layer is preferably from a monomer in which the ratio of the number of hydroxyl groups per monomer molecule to the molecular weight of the monomer is less than 0.4% from the viewpoint that the puncture elastic modulus of the liquid crystal cured layer can be easily adjusted to the above-mentioned preferable range. It is preferably composed of the obtained resin. When the resin constituting the alignment layer is a resin obtained by polymerizing two or more monomers, the ratio of the number of hydroxyl groups per monomer molecule to the molecular weight of the monomer for each monomer is calculated, and the ratio and each of them. The weighted average value may be calculated from the mixing ratio of the monomers, and the ratio of the number of hydroxyl groups may be calculated. The ratio of the number of hydroxyl groups per molecule of the monomer to the molecular weight of the monomer is preferably less than 0.4%, more preferably 0.35% or less, still more preferably 0.30% or less, and 0%. May be good.

により算出されるＮが０．６７以下であることが好ましい。液晶硬化層の突刺し弾性率を上記の好ましい範囲に調整しやすい観点から、上記のＮは、より好ましくは０．６４以下、さらに好ましくは０．５０以下である。また、上記のＮは、高温環境下における耐久性を維持する観点からは、好ましくは０．０１以上、より好ましくは０．０３以上、さらに好ましくは０．１５以上である。 (Layer containing cured product of polymerizable liquid crystal compound and orientation layer)
As described above, the liquid crystal cured layer of the present invention includes an oriented layer and a layer containing a cured product of a polymerizable liquid crystal compound, and preferably a layer in which an oriented layer and a layer containing a cured product of a polymerizable liquid crystal compound are laminated. Is. In the liquid crystal cured layer of the present invention, from the viewpoint that the puncture elastic modulus of the liquid crystal cured layer can be easily adjusted to the above-mentioned preferable range, the following formula (A):

It is preferable that N calculated by the above is 0.67 or less. From the viewpoint of easily adjusting the puncture elastic modulus of the liquid crystal cured layer to the above-mentioned preferable range, the above-mentioned N is more preferably 0.64 or less, still more preferably 0.50 or less. Further, the above N is preferably 0.01 or more, more preferably 0.03 or more, still more preferably 0.15 or more, from the viewpoint of maintaining durability in a high temperature environment.

Here, each symbol in the above formula (A) will be described.
AL represents the number of types of structural units derived from the polymerizable compound that constitutes the resin that constitutes the alignment layer. When the liquid crystal cured layer does not include the alignment layer, AL = 0.
C _wi, based on the total structural units derived from a polymerizable compound in the resin constituting the orientation layer, shows a content of a constitutional unit derived from a polymerizable compound i (wt%), M _i is an alignment layer The molecular weight of the constituent polymerizable compound _i is indicated, and Ni indicates the number of polymerizable groups contained in the polymerizable compound i constituting the alignment layer.
LC represents the number of types of structural units derived from the polymerizable liquid crystal compound constituting the layer with respect to the layer containing the cured product of the polymerizable liquid crystal compound.
C _wj indicates the content (mass%) of the structural units derived from the polymerizable liquid crystal compound j based on all the structural units derived from the polymerizable liquid crystal compound in the layer containing the cured product of the polymerizable liquid crystal compound. _j indicates the molecular weight of _{the polymerizable liquid crystal compound j constituting the layer, and N j} indicates the number of polymerizable groups contained in the polymerizable liquid crystal compound j constituting the layer.
L _AL denotes the thickness of the alignment layer (μm), L _LC denotes the thickness of the layer comprising the cured product of the polymerizable liquid crystal compound ([mu] m). L _total indicates the sum of L _AL and _LLC.

<Base layer>
The laminate of the present invention includes a first base material layer and a second base material layer. The first base material layer and the second base material layer are laminated so as to be peelable from the first liquid crystal cured layer and the second liquid crystal cured layer, respectively, and these base materials function as a releasable support. However, a liquid crystal cured layer (preferably a retardation layer) for transfer and an orientation layer can be supported. The base material is a translucent (preferably optically transparent) thermoplastic resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornen resin or the like). Polyolefin resin; Cellulosic resin such as triacetyl cellulose and diacetyl cellulose; Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resin; (Meta) acrylic resin such as methyl methacrylate resin; Polystyrene Resins; Polyvinyl chloride resins; Acrylonitrile, butadiene, styrene resins; Acrylonitrile, styrene resins; Polyvinyl acetate resins; Polyvinylidene chloride resins; Polyamide resins; Polyacetal resins; Modified polyphenylene ether resins; Polysulfones Examples thereof include a film made of a based resin; a polyether sulfone resin; a polyarylate resin; a polyamide imide resin; a polyimide resin; a maleimide resin and the like.

The thickness of the base material layer is not particularly limited, but is preferably 20 μm or more, more preferably 35 μm or more, preferably 200 μm or less, and more preferably 105 μm or less. When the thickness of the base material is at least the above lower limit, it is easy to impart strength to the laminate, and when it is at least the above upper limit, it is easy to handle when the laminate is lengthened. The thickness of the base material can be measured by, for example, a contact type film thickness meter (MH-15M manufactured by Nikon Corporation).

The base material layer may be subjected to various blocking prevention treatments. Examples of the blocking prevention treatment include an easy-adhesion treatment, a treatment of kneading a filler and the like, an embossing treatment (knurling treatment) and the like. By applying such a blocking prevention treatment to the base material, it is possible to effectively prevent the base materials from sticking to each other when the base material is wound, so-called blocking, and the laminated body and the optical laminated body can be efficiently prevented. It is possible to manufacture the product easily, and it is easy to improve the productivity.

<Adhesive layer>
The laminated body and the optical laminated body of the present invention include an adhesive layer between the first liquid crystal cured layer and the second liquid crystal cured layer. The adhesive layer may be either an adhesive layer formed by an adhesive or an adhesive layer formed by an adhesive. In the present specification, the adhesive layer is a layer having viscosity even after bonding, and is not usually in a solid state. The adhesive layer is a layer that becomes solid by curing or the like after bonding. Usually, when the liquid crystal cured layer is laminated via the adhesive layer, cracks tend to occur due to a sudden temperature change and peeling tends to occur when the base material layer is peeled off. However, according to the laminated body and the optical laminated body of the present invention, even when the first liquid crystal cured layer and the second liquid crystal cured layer are laminated via the adhesive layer, the above-mentioned cracks and cracks and The occurrence of peeling can be sufficiently suppressed. In particular, peeling when peeling the base material layer is likely to occur when these layers are laminated via an adhesive layer, but according to the laminated body and the optical laminated body of the present invention, the first liquid crystal cured layer and Even when the second liquid crystal cured layer is laminated via the adhesive layer, the occurrence of the above-mentioned peeling can be sufficiently suppressed.

From the viewpoint of easily adjusting the tensile modulus of the optical stack, the tensile modulus of the adhesive layer is preferably 2200N / mm ² or less, more preferably 1900 N / mm ² or less, more preferably 1500 N / mm ² or less, Even more preferably, it is 1300 N / mm ² or less. The tensile elastic modulus of the adhesive layer is measured by the method described in Examples described later.

(Adhesive layer)
The adhesive layer contains a resin such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a polyvinyl ether resin as a main component. Among the above resins, (meth) acrylic resins are preferable from the viewpoint of excellent transparency, weather resistance, heat resistance and the like. In the present specification, the composition for forming the pressure-sensitive adhesive layer is also referred to as a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type composition. The thickness of the adhesive layer is preferably 3 to 30 μm, more preferably 3 to 25 μm.

Examples of the (meth) acrylic resin (base polymer) contained in the adhesive layer include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Examples thereof include polymers or copolymers in which one or more of such (meth) acrylic acid esters are used as monomers. It is preferable to copolymerize the polar monomer in the base polymer as described above. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meta) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

(Adhesive layer)
Examples of the adhesive forming the adhesive layer include water-based adhesives and curable adhesives that can be cured by active energy rays or heat. Examples of the active energy ray include ultraviolet rays, visible light, electron beams, X-rays and the like. When an adhesive layer is formed using a curable adhesive, the cured product of these curable adhesives constitutes the adhesive layer. Among the above adhesives, a curable adhesive that can be cured by active energy rays or heat is preferable, and an active energy ray-curable adhesive is more preferable, because the drying step of heating to remove the solvent can be omitted. ..

Examples of the water-based adhesive include a composition in which a polyvinyl alcohol-based resin or a urethane resin is dissolved in water or dispersed in water as a main component, and the composition includes a polyhydric aldehyde, a melamine-based compound, and a zirconia. It may further contain curable components and cross-linking agents such as compounds, zinc compounds, glioxal and water-soluble epoxy resins.

The curable adhesive usually contains a curable compound as a main component. Curable adhesives are classified according to their curing mode, and are cationically polymerizable adhesives containing a cationically polymerizable compound as the curable compound, radically polymerizable adhesives containing a radically polymerizable compound as the curable compound, and cationically polymerized. Examples thereof include a hybrid curable adhesive containing both a sex compound and a radically polymerizable compound. Specific examples of the cationically polymerizable compound include an epoxy compound having one or more epoxy groups in the molecule, an oxetane compound having one or more oxetane rings in the molecule, and a vinyl compound. Specific examples of the radically polymerizable compound include (meth) acrylic compounds and vinyl compounds having one or more (meth) acryloyl groups in the molecule. The curable adhesive may contain one or more cationically polymerizable compounds and / or may contain one or more radically polymerizable compounds.

The cationically polymerizable compound, which is the main component of the cationically polymerizable adhesive, refers to a compound or oligomer in which the cationic polymerization reaction proceeds and is cured by irradiation or heating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. , Epoxy compounds, oxetane compounds, vinyl compounds and the like can be exemplified. Among them, the preferred cationically polymerizable compound is an epoxy compound. The epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. Only one type of epoxy compound may be used alone, or two or more types may be used in combination. Examples of the epoxy compound include an alicyclic epoxy compound, an aromatic epoxy compound, a hydrogenated epoxy compound, and an aliphatic epoxy compound. Among them, from the viewpoint of weather resistance, curing rate and adhesiveness, the epoxy compound preferably contains an alicyclic epoxy compound and / or an aliphatic epoxy compound, and more preferably contains an alicyclic epoxy compound.

The alicyclic epoxy compound is a compound having one or more epoxy groups bonded to the alicyclic ring in the molecule. The "epoxy group bonded to the alicyclic ring" means a bridging oxygen atom-O-in the structure represented by the following formula (I). In the following formula (I), m is an integer of 2 to 5.

A compound in which a group in the form of removing one or a plurality of hydrogen atoms _{in (CH 2} ) _m in the above formula (I) is bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. As the compound represented by the formula (I), a compound having an epoxycyclopentane structure having m = 3 and a compound having an epoxy cyclohexane structure having m = 4 are preferable.

Specific examples of the alicyclic epoxy compound include: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6. -Methylcyclohexanecarboxylate, ethylenebis (3,4-epoxycyclohexanecarboxylate), bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, diethyleneglycolbis (3,4-epoxycyclohexylmethyl) adipate 3,4-Epoxycyclohexylmethyl ether), ethylene glycol bis (3,4-epoxycyclohexylmethyl ether), 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispyro [5.2 .2.5.2.2] Henikosan, 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane, 4-vinylcyclohexene dioxide, limonendioxide , Bis (2,3-epoxycyclopentyl) ether, dicyclopentadiendioxide.

An aromatic epoxy compound is a compound having an aromatic ring and an epoxy group in the molecule. Specific examples thereof include bisphenol type epoxy compounds such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether or oligomers thereof; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac. Novolac type epoxy resin such as epoxy resin; polyfunctional epoxy such as 2,2', 4,4'-tetrahydroxydiphenylmethane glycidyl ether, 2,2', 4,4'-tetrahydroxybenzophenone glycidyl ether Compounds: Polyfunctional epoxy resins such as epoxidized polyvinylphenol can be mentioned.

The hydrogenated epoxy compound is a glycidyl ether of a polyol having an alicyclic ring, and is a nuclear hydrogenated poly obtained by selectively hydrogenating an aromatic polyol on an aromatic ring under pressure in the presence of a catalyst. It can be a glycidyl etherified hydroxy compound. Specific examples of the aromatic polyol include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; novolak-type resins such as phenol novolac resin, cresol novolac resin, and hydroxybenzaldehyde phenol novolac resin; tetrahydroxydiphenylmethane and tetrahydroxy. Examples thereof include polyfunctional compounds such as benzophenone and polyvinylphenol. A glycidyl ether can be obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol with epichlorohydrin. Among the hydrogenated epoxy compounds, the diglycidyl ether of hydrogenated bisphenol A can be mentioned.

［式（ＩＩ）中、Ｙは、炭素数２〜９のアルキレン基、エーテル結合が介在している総炭素数４〜９のアルキレン基、又は脂環構造を有する炭素数６〜１８の２価の炭化水素を表す］
で表される化合物である。式（ＩＩ）で表される脂肪族ジエポキシ化合物としては、具体的には、アルカンジオールのジグリシジルエーテル、繰り返し数４程度までのオリゴアルキレングリコールのジグリシジルエーテル、又は脂環式ジオールのジグリシジルエーテルが挙げられる。 The aliphatic epoxy compound is a compound having at least one oxylan ring (three-membered cyclic ether) bonded to an aliphatic carbon atom in the molecule. For example, monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4- Bifunctional epoxy compounds such as cyclohexanedimethanol diglycidyl ether; trifunctional or higher functional epoxy compounds such as trimethylolpropan triglycidyl ether and pentaerythritol tetraglycidyl ether; alicyclic such as 4-vinylcyclohexene dioxide and limonendioxide. There are epoxy compounds having one epoxy group directly bonded to the formula ring and an oxylane ring bonded to an aliphatic carbon atom. Of these, a bifunctional epoxy compound (also referred to as an aliphatic diepoxy compound) having two oxylan rings bonded to an aliphatic carbon atom in the molecule is preferable from the viewpoint of adhesiveness between the polarizing film and the protective film. Such a suitable aliphatic diepoxy compound is, for example, the following formula (II):

[In formula (II), Y is an alkylene group having 2 to 9 carbon atoms, an alkylene group having a total carbon number of 4 to 9 intervening an ether bond, or a divalent carbon number of 6 to 18 having an alicyclic structure. Represents the hydrocarbon of]
It is a compound represented by. Specific examples of the aliphatic diepoxy compound represented by the formula (II) include diglycidyl ether of alkanediol, diglycidyl ether of oligoalkylene glycol up to about 4 repetitions, and diglycidyl ether of alicyclic diol. Can be mentioned.

Specific examples of the diol (glycol) capable of forming the aliphatic diepoxy compound represented by the above formula (II) are listed below. Alkanediols include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and 1,4-butanediol. , Neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentane Diol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptandiol, 1,8-octanediol, 2-methyl-1,8 There are −octanediol, 1,9-nonanediol and the like. Examples of the oligoalkylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol and the like. Examples of the alicyclic diol include cyclohexanediol such as 1,2-cyclohexanediol, 1,3-cyclohexanediol, and 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1, There are cyclohexanedimethanol and the like such as 4-cyclohexanedimethanol.

An oxetane compound, which is one of the cationically polymerizable compounds, is a compound containing one or more oxetane rings (oxetanyl groups) in the molecule, and specific examples thereof are 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol). Also called), 2-ethylhexyloxetane, 1,4-bis [{(3-ethyloxetane-3-yl) methoxy} methyl] benzene (also called xylylenebis oxetane), 3-ethyl-3 [{( 3-Ethyloxetane-3-yl) methoxy} methyl] oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3- (cyclohexyloxy) methyl-3-ethyloxetane. The oxetane compound may be used as the main component of the cationically polymerizable compound, or may be used in combination with the epoxy compound. The combined use of an oxetane compound may improve the curing rate and adhesiveness.

Examples of the vinyl compound that can be a cationically polymerizable compound include an aliphatic or alicyclic vinyl ether compound, and specific examples thereof include n-amyl vinyl ether, i-amyl vinyl ether, n-hexyl vinyl ether, and n-octyl vinyl ether. , 2-Ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, oleyl vinyl ether and other alkyl or alkenyl alcohol vinyl ethers having 5 to 20 carbon atoms; 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether and the like. Hydroxyl group-containing vinyl ether; monoalcohol vinyl ether having an aliphatic ring or aromatic ring such as cyclohexyl vinyl ether, 2-methylcyclohexylvinyl ether, cyclohexylmethylvinyl ether, benzylvinyl ether; glycerol monovinyl ether, 1,4-butanediol monovinyl ether, 1, 4-Butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol tetravinyl ether, trimethylolpropane divinyl ether, trimethylolpropanetrivinyl ether, 1,4-dihydroxycyclohexane Mono-polyvinyl ethers of polyhydric alcohols such as monovinyl ether, 1,4-dihydroxycyclohexanedivinyl ether, 1,4-dihydroxymethylcyclohexanemonovinyl ether, 1,4-dihydroxymethylcyclohexanedivinyl ether; diethylene glycol divinyl ether, triethylene glycol di Polyalkylene glycol mono-divinyl ethers such as vinyl ether and diethylene glycol monobutyl monovinyl ether; other vinyl ethers such as glycidyl vinyl ether and ethylene glycol vinyl ether methacrylate can be mentioned. The vinyl compound may be used as a main component of the cationically polymerizable compound, or may be used in combination with an epoxy compound, or an epoxy compound and an oxetane compound. By using a vinyl compound in combination, it may be possible to improve the curing speed and the viscosity reduction of the adhesive.

The cationically polymerizable adhesive may further contain other cationically polymerizable compounds other than the above, such as a cyclic lactone compound, a cyclic acetal compound, a cyclic thioether compound, and a spiroorthoester compound.

From the viewpoint of easily improving the adhesiveness, when the total amount of the curable compound contained in the cationically polymerizable adhesive (including the case where it is a hybrid type curable adhesive) is 100% by weight, the cationically polymerizable compound The content (content of all cationically polymerizable compounds contained in the cationically polymerizable adhesive, and if two or more kinds of cationically polymerizable compounds are contained, the total content thereof) is preferably 50% by weight. As mentioned above, it is more preferably 60% by weight or more, still more preferably 70% by weight or more. Further, as described above, the cationically polymerizable adhesive may further contain a polymer component (thermoplastic resin or the like).

The cationically polymerizable adhesive may be active energy ray-curable or thermosetting, but it is possible to omit the heating step and prevent deformation due to heating of the laminate. From the viewpoint of ease of use, it is preferably active energy ray curable. When imparting active energy ray curability to a cationically polymerizable adhesive containing a cationically polymerizable compound, it is preferable to add a photocationic polymerization initiator to the adhesive. The photocationic polymerization initiator generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiates a polymerization reaction of a cationically curable compound. .. Since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a photocationic curable compound. Examples of the compound that produces a cationic species or Lewis acid by irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, and iron-alene complexes.

The aromatic iodonium salt is a compound having a diaryliodonium cation, and examples of the cation include a diphenyliodonium cation. The aromatic sulfonium salt is a compound having a triarylsulfonium cation, and examples of the cation include a triphenylsulfonium cation and a 4,4'-bis (diphenylsulfonio) diphenylsulfide cation. The aromatic diazonium salt is a compound having a diazonium cation, and examples of the cation include a benzenediazonium cation. Also, the iron-arene complex is typically a cyclopentadienyl iron (II) arene cationic complex salt.

The cations shown above are paired with anions (anions) to form a photocationic polymerization initiator. Examples of anions which constitute the photo-cationic polymerization initiator, a special phosphorus based anions _{[(Rf) n PF 6-} n] -, hexafluorophosphate anion PF ₆ ^-, hexafluoroantimonate anion SbF ₆ ^-, pentafluorophenyl hydroxy antimonate anion _SbF 5 (OH) ^-, hexafluoro ah cell anions AsF ₆ ^-, tetrafluoroborate anion BF ₄ ^-, tetrakis (pentafluorophenyl) borate anion _{B (C 6 F 5) 4} - and the like. Among them, from the viewpoint of curability of the cationically polymerizable compound and the safety of the obtained adhesive layer, the special phosphorus anion [(Rf) _n PF _6-n ] ⁻ and the hexafluorophosphate anion PF ₆ ⁻ are preferable. ..

As the photocationic polymerization initiator, only one kind may be used alone, or two or more kinds may be used in combination. Among them, the aromatic sulfonium salt is preferably used because it has an ultraviolet absorbing property even in a wavelength region near 300 nm, and thus can give a cured product having excellent curability and good mechanical strength and adhesive strength.

The blending amount of the photocationic polymerization initiator is usually 0.5 to 10 parts by weight, preferably 6 parts by weight or less, based on 100 parts by weight of the cationically polymerizable compound. By blending 0.5 parts by weight or more of the photocationic polymerization initiator, the cationically polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be imparted to the obtained polarizing plate. On the other hand, if the amount is excessively large, the amount of ionic substances in the cured product increases, so that the hygroscopicity of the cured product increases, and the durability of the polarizing plate may decrease.

As described above, a hybrid type curable adhesive can also be obtained by containing a radically polymerizable compound in addition to the cationically polymerizable compound in the cationically polymerizable adhesive. By using the radically polymerizable compound in combination, the effect of increasing the hardness and mechanical strength of the adhesive layer can be expected, and further, the viscosity and curing rate of the curable adhesive can be adjusted more easily.

The radically polymerizable compound, which is the main component of the radical polymerization type adhesive, refers to a compound or oligomer in which the radical polymerization reaction proceeds by irradiation or heating with active energy rays such as ultraviolet rays, visible light, electron beams, and X rays, and the radical polymerization reaction proceeds and is cured. Specifically, a compound having an ethylenically unsaturated bond can be mentioned. Compounds having an ethylenically unsaturated bond include (meth) acrylic compounds having one or more (meth) acryloyl groups in the molecule, styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. Examples thereof include vinyl compounds such as -2-pyrrolidone. Among them, the preferred radically polymerizable compound is a (meth) acrylic compound.

The (meth) acrylic compound is obtained by reacting two or more kinds of a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule, a (meth) acrylamide monomer, and a functional group-containing compound. Examples thereof include (meth) acryloyl group-containing compounds such as (meth) acrylic oligomers having at least two (meth) acryloyl groups in the molecule. The (meth) acrylic oligomer is preferably a (meth) acrylate oligomer having at least two (meth) acryloyloxy groups in the molecule. As the (meth) acrylic compound, only one kind may be used alone, or two or more kinds may be used in combination.

The (meth) acrylate monomer includes a monofunctional (meth) acrylate monomer having one (meth) acryloyloxy group in the molecule and a bifunctional (meth) acrylate having two (meth) acryloyloxy groups in the molecule. Monomers and polyfunctional (meth) acrylate monomers having three or more (meth) acryloyloxy groups in the molecule can be mentioned.

An example of a monofunctional (meth) acrylate monomer is an alkyl (meth) acrylate. In an alkyl (meth) acrylate, the alkyl group may be linear or branched as long as it has 3 or more carbon atoms. Specific examples of alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and the like. Examples thereof include 2-ethylhexyl (meth) acrylate. Also, aralkyl (meth) acrylates such as benzyl (meth) acrylates; (meth) acrylates of terpen alcohols such as isobornyl (meth) acrylates; (meth) having a tetrahydrofurfuryl structure such as tetrahydrofurfuryl (meth) acrylates. ) Acrylate; has a cycloalkyl group at the alkyl group moiety such as cyclohexyl (meth) acrylate, cyclohexylmethyl methacrylate, dicyclopentanyl acrylate, dicyclopentenyl (meth) acrylate, 1,4-cyclohexanedimethanol monoacrylate (meth). ) Acrylate; Aminoalkyl (meth) acrylate such as N, N-dimethylaminoethyl (meth) acrylate; 2-phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate , (Meta) acrylate having an ether bond at the alkyl moiety such as phenoxypolyethylene glycol (meth) acrylate can also be used as the monofunctional (meth) acrylate monomer.

Further, a monofunctional (meth) acrylate having a hydroxyl group at the alkyl moiety and a monofunctional (meth) acrylate having a carboxyl group at the alkyl moiety can also be used. Specific examples of the monofunctional (meth) acrylate having a hydroxyl group at the alkyl moiety include 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy. -3-Phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate are included. Specific examples of the monofunctional (meth) acrylate having a carboxyl group at the alkyl moiety include 2-carboxyethyl (meth) acrylate, ω-carboxy-polycaprolactone (n≈2) mono (meth) acrylate, 1- [2- ( Meta) acryloyloxyethyl] phthalic acid, 1- [2- (meth) acryloyloxyethyl] hexahydrophthalic acid, 1- [2- (meth) acryloyloxyethyl] succinic acid, 4- [2- (meth) acryloyl Oxyethyl] Trimellitic acid, N- (meth) acryloyloxy-N', N'-dicarboxymethyl-p-phenylenediamine.

The (meth) acrylamide monomer is preferably (meth) acrylamide having a substituent at the N-position, and a typical example of the substituent at the N-position is an alkyl group, but the nitrogen atom of (meth) acrylamide. It may form a ring with the ring, and the ring may have an oxygen atom as a ring member in addition to the carbon atom and the nitrogen atom of (meth) acrylamide. Further, a substituent such as alkyl or oxo (= O) may be bonded to the carbon atom constituting the ring.

Specific examples of N-substituted (meth) acrylamide are N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, and Nt-. N-alkyl (meth) acrylamide such as butyl (meth) acrylamide, N-hexyl (meth) acrylamide; N, N- such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide. Contains dialkyl (meth) acrylamide. Further, the N-substituted group may be an alkyl group having a hydroxyl group, and examples thereof include N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, and N- (2-hydroxy). There are propyl) (meth) acrylamide and the like. Furthermore, specific examples of the N-substituted (meth) acrylamide forming the above-mentioned 5-membered ring or 6-membered ring include N-acryloylpyrrolidine, 3-acryloyl-2-oxazolidinone, 4-acryloylmorpholine, and N-acryloyl. There are piperidine, N-methacryloyl piperidine and the like.

Examples of the bifunctional (meth) acrylate monomer include alkylene glycol di (meth) acrylate, polyoxyalkylene glycol di (meth) acrylate, halogen-substituted alkylene glycol di (meth) acrylate, aliphatic polyol di (meth) acrylate, and hydrogenation. Di (meth) acrylate of dicyclopentadiene or tricyclodecanediakanol, di (meth) acrylate of dioxane glycol or dioxandialkanol, di (meth) acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, bisphenol A or bisphenol Examples thereof include the epoxy di (meth) acrylate of F.

To give a more specific example of the bifunctional (meth) acrylate monomer, ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1 , 6-Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylpropandi (meth) acrylate, pentaerythritol di (meth) acrylate, ditri Methylolpropandi (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, Polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, silicone di (meth) acrylate, hydroxypivalate neopentyl glycol ester di (meth) acrylate, 2,2-bis [4- (meth) Acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadienyldi (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate , 1,3-Dioxane-2,5-diyldi (meth) acrylate [also known as dioxane glycol di (meth) acrylate], acetal compound of hydroxypivalaldehyde and trimethylpropane [chemical name: 2- (2-hydroxy) -1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] di (meth) acrylate, tris (hydroxyethyl) isocyanurate di (meth) acrylate, 1,4-cyclohexanedi Methanol diacrylate and the like.

Examples of the trifunctional or higher functional polyfunctional (meth) acrylate monomer include glycerin tri (meth) acrylate, alkoxylated glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylol. Propanetetra (meth) acrylate, pentaerythritol trimethylolpropane (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Poly (meth) acrylates of trifunctional or higher functional aliphatic polyols are typical, and in addition, poly (meth) acrylates of trifunctional or higher functional halogen-substituted polyols and glycerin alkylene oxide adduct tri (meth) Acrylate, tri (meth) acrylate of alkylene oxide adduct of trimethylolpropane, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate tri (meth) acrylate and the like. Be done.

On the other hand, the (meth) acrylic oligomer includes urethane (meth) acrylic oligomer, polyester (meth) acrylic oligomer, epoxy (meth) acrylic oligomer and the like.

A urethane (meth) acrylic oligomer is a compound having a urethane bond (-NHCOO-) and at least two (meth) acryloyl groups in the molecule. Specifically, a urethanization reaction product of a hydroxyl group-containing (meth) acrylic monomer having at least one (meth) acryloyl group and at least one hydroxyl group in the molecule and polyisocyanate, or a polyol as polyisocyanate. It can be a urethanization reaction product of a terminal isocyanato group-containing urethane compound obtained by reaction and a (meth) acrylic monomer having at least one (meth) acryloyl group and at least one hydroxyl group in the molecule. ..

The hydroxyl group-containing (meth) acrylic monomer used in the urethanization reaction can be, for example, a hydroxyl group-containing (meth) acrylate monomer, and specific examples thereof include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth). ) Acrylate, 2-Hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerindi (meth) acrylate, trimethylpropandi (meth) acrylate, pentaerythritol tri (meth) acrylate, di Contains pentaerythritol penta (meth) acrylate. Specific examples other than the hydroxyl group-containing (meth) acrylate monomer include N-hydroxyalkyl (meth) acrylamide monomers such as N-hydroxyethyl (meth) acrylamide and N-methylol (meth) acrylamide.

Examples of the polyisocyanate used for the urethanization reaction with the hydroxyl group-containing (meth) acrylic monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and aromatic diisocyanates. Diisocyanates obtained by hydrogenating isocyanates (for example, hydrogenated tolylene diisocyanates, hydrogenated xylylene diisocyanates, etc.), di- or tri-isocyanates such as triphenylmethane triisocyanates, dibenzylbenzene triisocyanates, and the above. Examples thereof include polyisocyanate obtained by increasing the amount of diisocyanate.

Further, as the polyol used to obtain a terminal isocyanato group-containing urethane compound by reaction with polyisocyanate, a polyester polyol, a polyether polyol, or the like can be used in addition to an aromatic, aliphatic or alicyclic polyol. it can. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, and ditri. Examples thereof include methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

The polyester polyol is obtained by a dehydration condensation reaction between the above-mentioned polyol and a polybasic carboxylic acid or an anhydride thereof. Examples of polybasic carboxylic acids or their anhydrides, which may be anhydrides, are represented by adding "(anhydride)" to (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous). There are itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, hexahydro (anhydrous) phthalic acid and the like.

In addition to the polyalkylene glycol, the polyether polyol may be the above-mentioned polyol or a polyoxyalkylene-modified polyol obtained by reacting dihydroxybenzenes with alkylene oxide.

A polyester (meth) acrylic oligomer is a compound having an ester bond and at least two (meth) acryloyl groups (typically (meth) acryloyloxy groups) in the molecule. Specifically, it can be obtained by a dehydration condensation reaction using (meth) acrylic acid, a polybasic carboxylic acid or an anhydride thereof, and a polyol. Examples of polybasic carboxylic acids or their anhydrides used in the dehydration condensation reaction, which can be anhydrous, are represented by adding "(anhydride)" to (anhydrous) succinic acid, adipic acid, (anhydride). There are maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the polyol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, and trimethylolpropane. Examples thereof include ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

The epoxy (meth) acrylic oligomer can be obtained, for example, by an addition reaction between polyglycidyl ether and (meth) acrylic acid, and has at least two (meth) acryloyloxy groups in the molecule. Examples of the polyglycidyl ether used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether.

The radical polymerization type adhesive may be active energy ray-curable or thermosetting, but is preferably active energy ray-curable. When imparting active energy ray curability to a radical polymerization type adhesive containing a radically polymerizable compound, it is preferable to add a photoradical polymerization initiator to the adhesive. The photoradical polymerization initiator initiates the polymerization reaction of a radical curable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. Only one type of photoradical polymerization initiator may be used alone, or two or more types may be used in combination.

Specific examples of photoradical initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[ Acetphenone-based initiators such as 4- (methylthio) phenyl-2-morpholinopropane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone, 4,4'. -Benzophenone-based initiators such as diaminobenzophenone; benzoin ether-based initiators such as benzoinpropyl ether and benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; ..

The blending amount of the photoradical polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the radically polymerizable compound. By blending 0.5 parts by weight or more of the photoradical polymerization initiator, the radically polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be given to the obtained laminate and the optical laminate. it can. On the other hand, if the amount is excessively large, the durability of the laminated body and the optical laminated body may decrease.

(Additive)
The adhesive layer and the pressure-sensitive adhesive and adhesive for forming the layer may contain other additives, if necessary. Specific examples of additives include ion trapping agents, antioxidants, chain transfer agents, polymerization promoters (polyols, etc.), sensitizers, sensitizing aids, light stabilizers, tackifiers, thermoplastic resins, fillers. , Flow conditioners, plasticizers, defoamers, leveling agents, silane coupling agents, dyes, antistatic agents, UV absorbers, thermal polymerization initiators. The thermal polymerization initiator is used in place of the photopolymerization initiator when preparing a thermosetting adhesive. A photopolymerization initiator and a thermal polymerization initiator can also be used in combination. Examples of the ion trap agent include powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based and mixed-based inorganic compounds, and examples of the antioxidant include hindered phenol-based antioxidants. And so on.

<Manufacturing method of laminated body>
The method for producing the laminate of the present invention will be described by taking the laminate shown in FIG. 1 as an example. Note that FIG. 1 is a schematic view for explaining the layer structure of the laminated body, and the thickness of each layer shown in FIG. 1 does not show a preferable relationship between the thickness of each layer. The laminate 100 shown in FIG. 1 is a first base material layer 111 / first liquid crystal cured layer 121 (first oriented layer 131 and first polymerizable liquid crystal cured product-containing layer 141) / adhesive layer 15 / second. It has a configuration including a liquid crystal cured layer 122 (second polymerizable liquid crystal cured product-containing layer 142 and second oriented layer 132) / second base material layer 112. In the laminated body according to the embodiment of the present invention shown in FIG. 1, when the first base material layer 111 is peeled off, the first alignment layer 131 is not peeled off together. Therefore, the first liquid crystal cured layer 121 is composed of the first oriented layer 131 and the first polymerizable liquid crystal cured product-containing layer 141. Further, when the second base material layer 112 is peeled off, the second alignment layer 132 is not peeled off together. Therefore, the second liquid crystal cured layer 122 is composed of the second oriented layer 132 and the second polymerizable liquid crystal cured product-containing layer 142.

The laminate of the present invention can usually be produced by a production method including at least an alignment layer forming step, a liquid crystal cured layer forming step, and a bonding step. Specifically, first, in the alignment layer forming step, the composition for forming the alignment layer is applied onto the base material. Examples of the coating method include known methods such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, a coating method such as an applicator method, and a printing method such as a flexographic method. When the laminate of the present invention is produced by a continuous method of Roll to Roll format, the coating method is preferably a printing method such as a gravure coating method, a die coating method, or a flexographic method. By applying the composition for forming an alignment layer onto a base material using the above method, a first coating film is formed on the base material. The alignment layer is formed by curing the first coating film as necessary and applying an orientation regulating force by a usual method such as photo-alignment or rubbing treatment. Here, before forming the alignment layer, the base material may be subjected to an easy adhesion treatment such as a saponification treatment, a corona discharge treatment, a plasma treatment, a flame treatment, a primer treatment, and an anchor coating treatment. By performing such a treatment, the adhesiveness between the base material and the alignment layer is weakened, and when the base material is peeled from the laminate, the alignment layer is not peeled off together with the base material and remains in the liquid crystal cured layer. can do.

Next, a composition containing a polymerizable liquid crystal compound is applied onto the alignment layer. As the coating method, the coating method described for the composition for forming an oriented layer may be used. Next, the polymerizable liquid crystal cured product-containing layer is formed by curing the polymerizable liquid crystal compound by heat treatment or irradiation with active energy rays in a state where the polymerizable liquid crystal compound is oriented. The composition containing the polymerizable liquid crystal compound may contain components other than the above-mentioned polymerizable liquid crystal compound. For example, the composition preferably contains a polymerization initiator. As the polymerization initiator used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of the polymerization reaction. For example, examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total solid content in the coating liquid. In the present invention, "cured" means a state in which the formed layer alone can exist independently without being deformed or flowed, and the puncture elastic modulus of the formed layer is preferably 3 g / mm. That is all.

Further, the composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Among them, a polyfunctional radically polymerizable monomer is preferable. The polymerizable monomer is preferably one that can be copolymerized with the above-mentioned polymerizable liquid crystal compound. The amount of the polymerizable monomer used is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, based on the total mass of the polymerizable liquid crystal compound.

Further, the composition may contain a surfactant from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the surfactant include conventionally known compounds. Among them, fluorine-based compounds are particularly preferable.

In addition, the composition may contain a solvent, and an organic solvent is preferably used. Examples of the organic solvent include amide (eg, N, N-dimethylformamide), sulfoxide (eg, dimethyl sulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, eg). , Chloroform, dichloromethane), esters (eg, methyl acetate, ethyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Among them, alkyl halides and ketones are preferable. Further, two or more kinds of organic solvents may be used in combination.

Further, the composition includes a vertical alignment promoter such as a polarizer interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment promotion agent such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Various orienting agents such as agents may be included. Further, the composition may contain an adhesion improver, a plasticizer, a polymer and the like in addition to the above components.

The active energy rays include ultraviolet rays, visible light, electron beams, and X-rays, and are preferably ultraviolet rays. Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excima laser, and a wavelength range. Examples thereof include an LED light source that emits 380 to 440 nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The irradiation intensity of ultraviolet radiation is typically the case of ultraviolet B wave (wavelength region ^{280～310Nm),} a ^{100mW / cm 2 ~3,000mW / cm 2} . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic polymerization initiator or the radical polymerization initiator. The time for irradiating with ultraviolet rays is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds. ~ 1 minute.

Ultraviolet rays can be irradiated once or in a plurality of times. Depending on the polymerization initiator used, the accumulated amount of light at a wavelength of 365nm is preferably in a 700 mJ / cm ² or more, more preferably, to 1,100mJ / cm ² or more, 1,300mJ / cm ² or more and It is more preferable to do so. The integrated light intensity is advantageous for increasing the polymerization rate of the polymerizable liquid crystal compound constituting the retardation film and improving the heat resistance. Integrated light intensity at a wavelength of 365nm is preferably in a 2,000 mJ / cm ² or less, and more preferably to 1,800mJ / cm ² or less. The integrated light intensity may cause coloring of the retardation film. Further, a cooling step may be provided after irradiation with ultraviolet rays. The cooling temperature can be, for example, 20 ° C. or lower, and can be 10 ° C. or lower. The cooling time can be, for example, 10 seconds or more, and 20 seconds or more.

As described above, the first laminated body including the first base material layer and the first liquid crystal cured layer is produced, and similarly, the second laminated body containing the second base material layer and the second liquid crystal cured layer is produced. To manufacture. The laminate of the present invention can be produced by laminating the two obtained laminates via an adhesive layer. When the laminated body has a long shape, the respective members may be bonded by roll-to-roll via an adhesive layer (preferably an adhesive layer).

Specifically, the pressure-sensitive adhesive composition or the adhesive composition is applied onto the first liquid crystal curing layer and / or the second liquid crystal curing layer, and these laminates are laminated via a coating film to form a coating film. The adhesive layer can be formed by drying the composition or curing the composition with active energy rays or heat. The adhesive and the adhesive may be applied by using various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater. Further, it is also possible to adopt a method in which the adhesive or the adhesive is cast while continuously supplying the first laminated body and the second laminated body so that the bonded surfaces are on the inner side.

<Manufacturing method of optical laminate>
The optical laminate of the present invention can be produced by peeling the first base material layer and the second base material layer from the laminate produced as described above.

<Use>
The optical laminate of the present invention can be used in various display devices. The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic EL display device, an inorganic electroluminescence (hereinafter, also referred to as inorganic EL) display device, an electron emission display device (for example, an electric field emission display device (also referred to as FED), and a surface electric field emission display. Device (also called SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, digital micromirror device (DMD)) (Also referred to as), a piezoelectric ceramic display, and the like. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, and the like. These display devices include a two-dimensional image. It may be a display device for displaying a three-dimensional image, or a three-dimensional display device for displaying a three-dimensional image. The optical laminate can be particularly effectively used for an organic EL display device or an inorganic EL display device. ..

Further, the display device can be a flexible display device, or can be a flexible organic EL display device. The flexible organic EL display device includes the optical laminate of the present invention and an organic EL display element. The optical laminate of the present invention is arranged on the visual side with respect to the organic EL display element, and is configured to be bendable. Bendable means that it can be bent without causing cracks and breaks. When the optical laminate of the present invention is applied to a flexible organic EL display device, it is preferable that the optical laminate is further laminated with at least one of a front plate and a touch sensor.

As a specific laminate, the front plate, the polarizing plate, the retardation film, and the touch sensor are laminated in this order from the visual side, or the front plate, the touch sensor, the polarizing plate, and the retardation film are laminated in this order from the visual side. Aspects can be mentioned. The presence of the polarizing plate on the visual side of the touch sensor is preferable because the pattern of the touch sensor is less likely to be visually recognized and the visibility of the displayed image is improved. Each member can be laminated using an adhesive, an adhesive, or the like. Further, a light-shielding pattern formed on at least one surface of any layer of the front plate, the polarizing plate, the retardation film, and the touch sensor can be provided.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "part" in Examples and Comparative Examples are mass% and parts by mass. The physical properties of each of the following examples were measured by the following methods.

(Measurement of puncture elastic modulus)
A film for forming a liquid crystal cured layer with a base material layer was cut into pieces of 40 mm × 40 mm. In addition, a 40 mm × 40 mm glued mount was prepared. This glued mount is cut out in a square having a central portion of 30 mm × 30 mm. The film was attached to the glued mount so that the surface of the liquid crystal cured layer was in contact with the glue on the glued mount. The base material layer was peeled off from the liquid crystal cured layer with the base material layer to prepare a sample for measuring the puncture elastic modulus.

The puncture elastic modulus was measured as follows. A needle was attached to a handy compression tester "NDG5 piercing tester, needle penetration measurement specification" manufactured by Kato Tech Co., Ltd. The needle was pierced perpendicularly to the film surface of the measurement sample. Measurement sample The stress F (g) immediately before the puncture test sample breaks and the strain amount S (mm) at that time are calculated, and the puncture elastic modulus (g / mm) is the stress F (g) / strain amount S. It was calculated from the formula (mm). This operation was performed on each of the five measurement samples, and the average value was used as the piercing elastic modulus. As the needle, a needle having a tip diameter of 1 mmφ and 0.5R was used. The speed at which the needle was pierced was 0.33 cm / sec. The measurement was performed in a room temperature environment with a temperature of 23 ° C. and a humidity of 50%.

(Measurement of tensile elastic modulus of optical laminate)
A method for preparing a measurement sample will be described with reference to FIG. The optical laminate with the double-sided base material layer was cut into pieces of 60 mm × 200 mm. Further, a 60 mm × 200 mm glued mount 17 was prepared. This glued mount has a cutout portion 18 cut out in a rectangular shape of 10 mm × 140 mm in the central portion. The first base material layer was peeled off from the optical laminate with the double-sided base material layer. The laminate was attached to the glued mount so that the surface of the first liquid crystal cured layer was in contact with the glue of the glued mount. Then, the second base material layer was peeled off. In this way, a sample as shown in FIG. 6 is obtained. The optical laminate 16 is present in the cutout portion 18, and the glued mount 17 and the optical laminate 16 are bonded to each other in the other portions. Next, a rectangular portion of 10 mm × 60 mm (the portion surrounded by the dotted line in FIG. 6) was cut so as to include the cutout portion 18 of the glued mount 17, and this was used as a measurement sample of tensile elastic modulus. ..
The tensile elastic modulus was measured according to JIS K7161. The tensile test was carried out by grasping the mount portions (hatched portions in FIG. 6) at both ends of the above-mentioned measurement sample and pulling them at a speed of 1 mm / min. The tensile test was carried out in a room temperature environment at a temperature of 23 ° C. and a humidity of 50%.

(Measurement of tensile elastic modulus of adhesive layer)
^{The tensile elastic modulus [N / mm 2} ] at a temperature of 30 ° C. when an active energy ray-curable adhesive was used as the adhesive layer was calculated by the following procedure. An active energy ray-curable adhesive is applied to one side of a cyclic polyolefin resin film having a thickness of 50 μm using a coating machine [Barcoater, manufactured by Daiichi Rika Co., Ltd.], and the coated surface is further coated with a thickness of 50 μm. A cyclic polyolefin resin film was laminated. Next, the adhesive composition layer was cured by irradiating with ultraviolet rays so that ^{the integrated light amount was 1500 mJ / cm 2} (UVB) by a "D bulb" manufactured by Fusion UV Systems. One of the cyclic polyolefin-based resin films was peeled off to obtain an adhesive layer with a resin film. The adhesive layer with a resin film was cut into pieces of 60 mm × 200 mm. Further, a 60 mm × 200 mm glued mount 17 was prepared. This glued mount has a cutout portion 18 cut out in a rectangular shape of 10 mm × 140 mm in the central portion. The adhesive layer with a resin film was attached to the adhesive mount so that the surface of the adhesive layer was in contact with the glue of the adhesive mount. Then, the other cyclic polyolefin resin film was peeled off. In this way, a sample as shown in FIG. 6 is obtained. An adhesive layer is present in the cutout portion 18, and the glued mount 17 and the adhesive layer are bonded to each other in other portions. Next, a rectangular portion of 10 mm × 60 mm (the portion surrounded by the dotted line in FIG. 6) was cut so as to include the cutout portion 18 of the glued mount 17, and this was used as a measurement sample of tensile elastic modulus. ..
The tensile elastic modulus was measured according to JIS K7161. The tensile test was carried out by grasping the mount portions (hatched portions in FIG. 6) at both ends of the above-mentioned measurement sample and pulling them at a speed of 1 mm / min. The tensile test was carried out in a room temperature environment at a temperature of 23 ° C. and a humidity of 50%. In addition, when the adhesive layer was used as the adhesive layer, the evaluation was performed using a sample having the same shape.

(Measurement of peeling force of base material layer)
Adhesive layer 1 (manufactured by Lintec Corporation, pressure-sensitive adhesive thickness 25 μm) was bonded to each of the obtained liquid crystal cured layer with a base material layer on the liquid crystal cured layer side. The laminate on which the pressure-sensitive adhesive layer 1 was formed was cut to prepare a test piece having a width of 25 mm and a length of about 150 mm. After the pressure-sensitive adhesive layer surface of the test piece was attached to the glass plate, a peeling tape (width 25 mm × length about 180 mm) was attached to the surface (one side of the width 25 mm) of the test piece on the base material layer side. One end of the peeling tape was grasped, the base material layer was peeled off using a tensile tester, and the peeling force was measured. The peeling test was performed in an atmosphere having a temperature of 23 ° C. and a relative humidity of 50%. The crosshead speed (grasping movement speed) was 300 mm / min. The peeling angle was 180 °. In this embodiment, as described above, the peeling force of the base material layer was applied using the liquid crystal cured layer with the base material layer before being bonded via the adhesive layer, but the peeling force of the base material layer was increased. It may be carried out using the laminated body after being bonded through the adhesive layer.

(Peelability test)
A 40 mm × 40 mm glued glass was prepared. The liquid crystal cured layer laminate with the double-sided base material layer was bonded so that the surface of the second base material layer was in contact with the glue in the glued glass. Subsequently, the first base material layer was peeled off. The peelability was evaluated according to the following criteria.
Good peelability: There is no peeling between the first liquid crystal cured layer and the second liquid crystal cured layer, and between the second liquid crystal cured layer and the second base material layer, and the first liquid crystal cured layer is the first. No peeling remained on the base material layer.
Poor peelability: There is peeling between the first liquid crystal cured layer and the second liquid crystal cured layer and / or between the second liquid crystal cured layer and the second base material layer, or the first liquid crystal cured layer. Remained peeled off in the first base material layer.
The same evaluation was performed on 24 samples, and when the number of samples with good peelability was 24 to 17, it was evaluated as ◎, when it was 16 to 9, it was evaluated as ○, and 8 to 0. In the case of, it was evaluated as ×.

(Thermal impact test)
Preparation of Polarizing Plate A 20 μm-thick polyvinyl alcohol film (average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched about 4 times by dry stretching, and 40 while maintaining a tense state. After immersing in pure water at ° C. for 40 seconds, the dyeing treatment was performed by immersing in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.052 / 5.7 / 100 at 28 ° C. for 30 seconds. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Subsequently, after washing with pure water at 8 ° C. for 15 seconds, while holding at a tension of 300 N, the iodine was adsorbed and oriented on the polyvinyl alcohol film by drying at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds. A polarizer having a thickness of 8 μm was obtained.

A water-based adhesive composed of an aqueous polyvinyl alcohol-based resin solution was applied to both sides of the obtained polarizer, and a cyclic olefin-based resin film (Zeonoa ZF14 manufactured by Nippon Zeon Co., Ltd.) and a triacetyl cellulose (TAC) film (Fuji Film Co., Ltd.) were applied. Fujitac TJ25) made by the company was pasted together. This long polarizing plate was cut into a square of 8 cm × 8 cm to obtain a polarizing plate.

Preparation of Samples for Thermal Impact Test Two pressure-sensitive adhesive layers 2 (thickness 25 μm, P-3132 manufactured by Lintec Corporation) with separators on both sides were prepared. One separator was peeled off from the pressure-sensitive adhesive layer 2 having separators on both sides and bonded to the TAC film side surface of the polarizing plate. The first base material layer was peeled off from the liquid crystal cured layer laminate with the double-sided base material layer, and the other separator was peeled off from the polarizing plate with the pressure-sensitive adhesive layer. Both were bonded so that the surface of the first liquid crystal cured layer was in contact with the pressure-sensitive adhesive layer. Further, the second base material layer is peeled off, one separator is peeled off from the pressure-sensitive adhesive layer 2 having separators on both sides of the other sheet, and the surface of the second liquid crystal cured layer is bonded so as to be in contact with the pressure-sensitive adhesive layer. did. The other release film laminated on the pressure-sensitive adhesive layer 2 was peeled off and bonded to the glass plate via the exposed pressure-sensitive adhesive layer. In this way, a thermal shock test consisting of a polarizing plate / adhesive layer 2 / optical laminate (laminate of a first liquid crystal cured layer, an adhesive layer and a second liquid crystal cured layer) / adhesive layer 2 / a glass plate. Samples were obtained. The obtained thermal shock test sample was evaluated by the following method.

Evaluation method The pen tip of an Eriksen pen (model number 318 manufactured by Eriksen Co., Ltd.) set to a load of 10 N was pressed against a sample for thermal shock test to form a starting point. Similar starting points were provided at equal intervals at two other locations (three locations in total). Then, three cycles of thermal shock resistance tests were carried out with one cycle of −20 ° C. for 30 minutes and 60 ° C. for 30 minutes. TSA-303EL-W manufactured by ESPEC CORPORATION was used for the thermal shock test. After 3 cycles, the length of cracks generated from each starting point was measured. The average value of the crack lengths generated from the three starting points was defined as the crack length (mm).
Those having a crack length of less than 1 mm were evaluated as ⊚, those having a crack length of 1 mm or more and less than 10 mm were evaluated as ◯, and those having a crack length of 10 mm or more were evaluated as x.

[Preparation of adhesive]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device and a nitrogen introduction tube, 95.0 parts by mass of n-butyl acrylate, 4.0 parts by mass of acrylate, and 2-hydroxyethyl acrylate 1. 0 parts by mass, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile were charged, and the air in the reaction vessel was replaced with nitrogen gas. The reaction solution was heated to 60 ° C. with stirring under a nitrogen atmosphere, reacted for 6 hours, and then cooled to room temperature. When the weight average molecular weight of a part of the obtained solution was measured, it was confirmed that a (meth) acrylic acid ester polymer having a weight average molecular weight of 1.8 million was produced.

100 parts by mass of the obtained (meth) acrylic acid ester polymer (solid content conversion value; the same applies hereinafter), 1.5 parts by mass of the isocyanate-based cross-linking agent, 0.30 parts by mass of the silane coupling agent, and ultraviolet rays shown below. 7.5 parts by mass of the curable compound and 0.5 parts by mass of the photopolymerization initiator were mixed. The solution was stirred well and diluted with ethyl acetate to give a coating solution of the pressure-sensitive adhesive composition.
-Isocyanate-based cross-linking agent: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, Coronate L)
-Silane coupling agent: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403)
-Ultraviolet curable compound: ethoxylated isocyanuric acid triacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd., A-9300)
-Photopolymerization initiator: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (BASF, Irgacure 907)

The release-treated surface (release layer surface) of the separator (SP-PLR382190 manufactured by Lintec Corporation) was coated with the coating solution by an applicator so that the thickness after drying was 5 μm. The coating film was dried at 100 ° C. for 1 minute, and another separator (SP-PLR38131 manufactured by Lintec Corporation) was attached thereto. ^{This adhesive layer is irradiated with ultraviolet rays (illumination 500 mW / cm 2} , integrated light amount 500 mJ / cm ² ) through a separator using an ultraviolet irradiation device with a belt conveyor (manufactured by Fusion UV Systems, Inc., a lamp uses a D bulb). And a pressure-sensitive adhesive layer was obtained. The tensile elastic modulus of the pressure-sensitive adhesive layer was 0.4 N / mm ² .

[Preparation of Adhesive 1]
The cationic curable components a1 to a3 shown below and the cationic polymerization initiator were mixed. The cationic polymerization initiator and sensitizer shown below were further mixed with the obtained mixture. The obtained solution was defoamed to obtain a photocurable adhesive 1. The following blending amount is based on the solid content.
Cation curable component a1 (70 parts): 3', 4'-epoxycyclohexylmethyl 3', 4'-epoxycyclohexanecarboxylate (CEL2021P, manufactured by Daicel Corporation)
Cation curable component a2 (20 parts): Neopentyl glycol diglycidyl ether (manufactured by Nagase ChemteX Corporation, EX-211)
Cation curable component a3 (10 parts): 2-ethylhexyl glycidyl ether (manufactured by Nagase ChemteX Corporation, EX-121)
-Cationic polymerization initiator (2.25 parts (solid content)): 50% propylene carbonate solution of CPI-100 (manufactured by Sun Appro Co., Ltd.) -Sensitizer (2 parts): 1,4-diethoxynaphthalene adhesive 1 The tensile elastic modulus of the adhesive layer obtained from the above was 1280.8 N / mm ² .

[Preparation of adhesive 2]
The cationic curable components a1, a4 to a6 shown below and the cationic polymerization initiator were mixed. The cationic polymerization initiator and sensitizer shown below were further mixed with the obtained mixture. The obtained solution was defoamed to obtain a photocurable adhesive 2. The following blending amount is based on the solid content.
Cation curable component a1 (7 parts): 3', 4'-epoxycyclohexylmethyl 3', 4'-epoxycyclohexanecarboxylate (CEL2021P, manufactured by Daicel Corporation)
-Cation curable component a4 (40 parts): Fluorene type epoxy resin (manufactured by Osaka Gas Chemical Co., Ltd., OGSOL EG-200)
Cation curable component a5 (33 parts): Neopentyl glycol diglycidyl ether (EX-211L manufactured by Nagase ChemteX Corporation)
Cation curable component a6 (20 parts): 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (Toagosei Co., Ltd., OXT-221)
-Cationic polymerization initiator (2.25 parts (solid content)): Trade name: 50% propylene carbonate solution of CPI-100 (manufactured by Sun Appro Co., Ltd.) -Sensitizer (2 parts): 1,4-diethoxynaphthalene The tensile elastic modulus of the adhesive layer obtained from the adhesive 2 was 1756.3 N / mm ² .

[Preparation of Adhesive 3]
The cationic curable components a1, a6, a7 and the cationic polymerization initiator shown below were mixed. The cationic polymerization initiator and sensitizer shown below were further mixed with the obtained mixture. The obtained solution was defoamed to obtain a photocurable adhesive 3. The following blending amount is based on the solid content.
Cation curable component a1 (32.5 parts): 3', 4'-epoxycyclohexylmethyl 3', 4'-epoxycyclohexanecarboxylate (CEL2021P, manufactured by Daicel Corporation)
Cation curable component a6 (50 parts): 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (Toagosei Co., Ltd., OXT-221)
Cation curable component a7 (17.5 parts): 1,2-epoxy-4- (2-oxylanyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (manufactured by Daicel Corporation, EHPE3150) )
-Cationic polymerization initiator (2.25 parts (solid content)): Trade name: 50% propylene carbonate solution of CPI-100 (manufactured by Sun Appro Co., Ltd.) -Sensitizer (2 parts): 1,4-diethoxynaphthalene The tensile elastic modulus of the adhesive layer obtained from the adhesive 3 was 2345.5 N / mm ² .

・溶剤（９５部）：シクロペンタノン [Preparation of composition (1) for forming a photoalignment layer]
The following components were mixed, and the obtained mixture was stirred at a temperature of 80 ° C. for 1 hour to obtain a composition for forming a photoalignment layer (1).
・ Photo-oriented material (5 parts):

-Solvent (95 parts): Cyclopentanone

[Preparation of composition (2) for forming an alignment layer]
As a composition for forming an oriented layer, 15 parts of diethylene glycol di (meth) acrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-600) and 1,6-hexanediol di (meth) acrylate (Shin-Nakamura Chemical Industry Co., Ltd.) , A-DCP) and 1.5 parts of Irgacure 907 (manufactured by BASF) as a photopolymerization initiator were dissolved in 70 parts of solvent methyl ethyl ketone to prepare an orientation layer forming composition (2). ..

[Preparation of composition (3) for forming an alignment layer]
As a composition for forming an oriented layer, 5 parts of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-DPH) and diethylene glycol di (meth) acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-600) 5 parts, Trimethylol Propanetriacrylate (A-TMPT, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts, 1,6-hexanediol di (meth) acrylate (A-DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 10 parts and 1.5 parts of Irgacure 907 (manufactured by BASF) as a photopolymerization initiator were dissolved in 70 parts of the solvent methyl ethyl ketone to prepare the composition (3) for forming an orientation layer.

[Preparation of composition (4) for forming an alignment layer]
10 parts of dipentaerythritol hexaacrylate (A-DPH, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 5 parts of diethylene glycol di (meth) acrylate (A-600, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), and trimethyl propantriacrylate. 10 parts (A-TMPT manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) and 5 parts of 1,6-hexanediol di (meth) acrylate (A-DCP manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) as a photopolymerization initiator 1.5 parts of Irgacure 907 (manufactured by BASF) was dissolved in 70 parts of the solvent methyl ethyl ketone to prepare the composition (4) for forming an orientation layer.

・重合性液晶化合物Ａ２（２０部）：

・重合開始剤（６部）：２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン（チバスペシャルティケミカルズ社製、イルガキュア３６９）
・溶剤（４００部）：シクロペンタノン [Preparation of composition (A-1) for forming a liquid crystal cured layer]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a liquid crystal cured layer forming composition (A-1). The polymerizable liquid crystal compound A1 and the polymerizable liquid crystal compound A2 were synthesized by the method described in JP-A-2010-31223.
-Polymerizable liquid crystal compound A1 (80 parts):

-Polymerizable liquid crystal compound A2 (20 parts):

-Polymerization initiator (6 parts): 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (manufactured by Ciba Specialty Chemicals, Irgacure 369)
-Solvent (400 parts): Cyclopentanone

・重合開始剤（０．５％）：イルガキュア９０７（ＢＡＳＦ社製）
・反応添加剤（１．１％）：Ｌａｒｏｍｅｒ（登録商標）ＬＲ−９０００（ＢＡＳＦ社製）
・溶剤（７９．１％）：プロピレングリコール１−モノメチルエーテル２−アセタート [Preparation of composition for forming a liquid crystal cured layer (B-1)]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour and then cooled to room temperature to obtain a liquid crystal cured layer forming composition (B-1).
-Polymerizable liquid crystal compound LC242 (manufactured by BASF) (19.2%):

-Polymerization initiator (0.5%): Irgacure 907 (manufactured by BASF)
-Reaction additive (1.1%): Laromer (registered trademark) LR-9000 (manufactured by BASF)
-Solvent (79.1%): Propylene glycol 1-monomethyl ether 2-acetylate

[Manufacturing of First Liquid Crystal Curing Layer (1-1) with First Base Material Layer]
A polyethylene terephthalate (PET) film having a thickness of 100 μm was prepared as the first base material layer. The surface of the first base material layer was corona-treated. The corona treatment was performed once using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Works Ltd.) under the conditions of an output of 0.3 kW and a processing speed of 3 m / min. The composition for forming a photoalignment layer (1) was coated on the corona-treated surface with a bar coater. The coating was dried at 80 ° C. for 1 minute. The coating film was subjected to polarized UV exposure with an integrated light amount of ^{100 mJ / cm 2} using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.) to obtain a photoaligned layer. The thickness of the obtained photoalignment layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 100 nm.

The composition for forming a liquid crystal cured layer (A-1) was applied onto the photoalignment layer using a bar coater. The coating was dried at 120 ° C. for 1 minute. The coating film was irradiated with ultraviolet rays using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio, Inc.). Ultraviolet irradiation was performed in a nitrogen atmosphere. The wavelength of ultraviolet rays was 365 nm, the irradiation intensity at a wavelength of 365 nm was 10 mW / cm ² , and the integrated light intensity was 1000 mJ / cm ² . In this way, the first liquid crystal cured layer (layer A-1) as the retardation layer was formed, and the first liquid crystal cured layer (1-1) with the first base material layer was obtained. The thickness of the first liquid crystal cured layer (layer A-1) was measured with a laser microscope and found to be 2 μm. The substrate peeling force of the first liquid crystal cured layer (1-1) with the first substrate layer was 0.10 N / 25 mm. The puncture elastic modulus of the first liquid crystal cured layer (1-1) was 22.3 g / mm.

[Manufacturing of second liquid crystal cured layer (2-1) with second base material layer]
As the second base material layer, a polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared. The surface of the second base material layer was corona-treated. The corona treatment was performed once using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Works Ltd.) under the conditions of an output of 0.3 kW and a processing speed of 3 m / min. The composition for forming an orientation layer (2) was coated on the corona-treated surface with a bar coater. The coating was dried at 90 ° C. for 1 minute. The coating film was irradiated with ultraviolet rays (UVB) so that the integrated light intensity was 220 mJ / cm ^{2, and an oriented layer was obtained.} The thickness of the obtained oriented layer was measured with a laser microscope and found to be 2.8 μm.

The liquid crystal cured layer forming composition (B-1) was applied onto the oriented layer using a bar coater. The coating was dried at 90 ° C. for 1 minute. The coating film was irradiated with ultraviolet rays using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio, Inc.). Ultraviolet irradiation was performed in a nitrogen atmosphere. The wavelength of ultraviolet rays was 365 nm, and the integrated light intensity at a wavelength of 365 nm was 500 mJ / cm ² . In this way, the second liquid crystal cured layer (layer B-1) as the retardation layer was formed to obtain the second liquid crystal cured layer (2-1) with the second base material layer. The thickness of the second liquid crystal cured layer (layer B-1) was measured with a laser microscope and found to be 0.6 μm. The substrate peeling force of the second liquid crystal cured layer (2-1) with the second substrate layer was 0.07 N / 25 mm. The puncture elastic modulus of the second liquid crystal cured layer (2-1) was 20.3 g / mm.

(Manufacturing of second liquid crystal cured layer (2-2) with second base material layer)
It was produced in the same manner as the production of the second liquid crystal cured layer (2-1) except that the composition for forming the alignment layer (3) was used instead of the composition for forming the alignment layer (2). Table 1 shows the orientation layer thickness, substrate peeling force, and piercing elastic modulus data.

(Manufacturing of Second Liquid Crystal Curing Layers (2-3) to (2-7) with Second Base Material Layer)
It was manufactured in the same manner as the second liquid crystal cured layer (2-1) except that the thickness of the oriented layer was changed. Table 1 shows the orientation layer thickness, substrate peeling force, and piercing elastic modulus data.

(Manufacturing of second liquid crystal cured layer (2-8) with second base material layer)
It was produced in the same manner as the production of the second liquid crystal cured layer (2-1) except that the composition for forming the alignment layer (4) was used instead of the composition for forming the alignment layer (2). Table 1 shows the orientation layer thickness, substrate peeling force, and piercing elastic modulus data.

[Example 1]
The surface of the first liquid crystal cured layer (1-1) with the first base material layer prepared above on the liquid crystal cured layer side was subjected to corona treatment (800 W, 10 m / min, bar width 700 mm, 1 Pass). One of the separators is peeled off from the adhesive layer having the separators on both sides prepared above, and the first liquid crystal curing layer (1-) with the first base material layer is used with a sticking device (“LPA3301” manufactured by Fujipla Co., Ltd.). It was bonded to the corona-treated surface of 1) to obtain a liquid crystal cured layer with an adhesive layer. Further, the surface of the second liquid crystal cured layer (2-1) with the second base material layer prepared above on the liquid crystal cured layer side is similarly subjected to corona treatment, and then the other of the liquid crystal cured layer with the adhesive layer is subjected to corona treatment. The separator was peeled off and bonded in the same manner as the corona-treated surface of the second liquid crystal cured layer (2-1) with the second base material layer to obtain a laminated body (I). The obtained laminate (I) was allowed to stand overnight in an environment of a temperature of 23 ° C. and a humidity of 50%. Table 1 shows the results of evaluating the peelability of the obtained liquid crystal cured layer laminate (I) with a double-sided substrate layer and the tensile elastic modulus of the optical laminate obtained by peeling both substrates.

[Example 2]
The surface of the second liquid crystal cured layer (1-1) with the first base material layer prepared above on the liquid crystal cured layer side was subjected to corona treatment (800 W, 10 m / min, bar width 700 mm, 1 Pass). The adhesive 1 prepared above was applied to the corona-treated surface using a coating machine (bar coater manufactured by Daiichi Rika Co., Ltd.). Next, the surface of the second liquid crystal cured layer (2-1) with the second base material layer prepared above on the liquid crystal cured layer side was subjected to corona treatment under the same conditions as described above. A device for attaching a first liquid crystal cured layer (1-1) with a first base material layer and a second liquid crystal cured layer (2-1) with a second base material layer via an adhesive 1 (manufactured by Fujipla Co., Ltd.). It was bonded using "LPA3301"). Ultraviolet rays are emitted from the base material layer side of the second liquid crystal curing layer (2-1) with the second base material layer using an ultraviolet irradiation device with a belt conveyor (the lamp uses an "H bulb" manufactured by Fusion UV Systems). Irradiated. UV irradiation, irradiation intensity 390mW / cm ² become a UVA range, integrated light quantity as a 420 mJ / cm ^2, so that 400 mW / cm ² next irradiation intensity in UVB range, the integrated light quantity becomes 400 mJ / cm ² I made it. In this way, the laminated body (II) was obtained. The thickness of the adhesive layer of the obtained laminate (II) was 1.5 μm. The obtained laminate (II) was allowed to stand overnight in an environment of a temperature of 23 ° C. and a humidity of 50%. Table 1 shows the results of evaluating the peelability of the obtained laminate (II) and the tensile elastic modulus of the optical laminate obtained by peeling both substrates.

[Examples 3 to 7, Comparative Examples 1 to 4]
The liquid crystal cured layer laminate with the double-sided base material layer (the liquid crystal cured layer laminate with the double-sided base material layer) in the same procedure as in Example 2 except that the second liquid crystal cured layer with the second base material layer and the adhesive used were changed as shown in Tables 1 and 2. III-XI) were obtained. Tables 1 and 2 show the results of evaluating the peelability and tensile elastic modulus of the obtained liquid crystal cured layer laminates (III to XI) with a double-sided base material layer. Regarding the bonding using the adhesive 2 or 3, the bonding was performed under the same conditions as in Example 2 using the adhesive 1. The thickness of the adhesive layer is 2.0 μm for the laminated body (III), 1.5 μm for the laminated body (IV), 2.0 μm for the laminated body (V), and 1.5 μm for the laminated body (VI). The body (VII) is 1.5 μm, the laminate (VIII) is 2.0 μm, the laminate (IX) is 1.5 μm, the laminate (X) is 1.5 μm, and the laminate (XI) is 1.5 μm. It was.

Further, Table 3 shows the results of calculating N according to the above formula (A) with respect to the liquid crystal cured layer and the oriented layer in the laminates of Examples and Comparative Examples.

As shown in Table 1, the optical laminates obtained in Examples 1 to 7 have good peelability of the base material layer, are unlikely to peel off between the liquid crystal curing layers, and are caused by a rapid temperature change. It was confirmed that the occurrence of cracks was suppressed. On the other hand, in the laminate shown in the comparative example, when the base material layer was peeled off, peeling was likely to occur even between the liquid crystal curing layers, or cracks were likely to occur due to a sudden temperature change.

1 Mount with measurement film 6 Void part 7 Adhesive mount 8 Outer circumference 12 Measurement film N Needle M Position where needle N is pierced S Strain amount 100 Laminated material 111 First base material layer 121 First liquid crystal curing layer 131 First alignment layer 141 First polymerizable liquid crystal cured product-containing layer 15 Adhesive layer 122 Second liquid crystal cured product 142 Second polymerizable liquid crystal cured product-containing layer 132 Second oriented layer 112 Second base material layer

Claims (9)

A laminate containing the first base material layer, the first liquid crystal cured layer, the adhesive layer, the second liquid crystal cured layer, and the second base material layer in this order.
Both the first liquid crystal cured layer and the second liquid crystal cured layer include a layer containing a cured product of a polymerizable liquid crystal compound and an orientation layer.
Each of the first liquid crystal cured layer and the second liquid crystal cured layer uses a measurement sample in which a film forming the layer is bonded to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and has a tip diameter. A needle of 1 mm φ0.5 R is pierced perpendicularly to the surface of the film at a speed of 0.33 cm / sec, and the amount of displacement due to bending of the film in the piercing direction, which is measured when a break occurs, is the amount of strain. When S (mm) and the stress applied to the film are F (g), the formula (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
The puncture elastic modulus calculated by
The first base material layer and the second base material layer can be peeled off from the first liquid crystal cured layer and the second liquid crystal cured layer, respectively, and among the first base material layer and the second base material layer, When the base material layer to be peeled off first is the first peeling layer and the base material layer to be peeled off later is the second peeling layer, the peeling force when peeling the first peeling layer is to peel off the second peeling layer. Greater than the peeling force when
The thickness of the alignment layer contained in the first liquid crystal cured layer is smaller than the thickness of the alignment layer contained in the second liquid crystal cured layer.
^{A laminate having a tensile elastic modulus of 1,000 N / mm 2} or less, which is obtained by peeling the first base material layer and the second base material layer from the laminate. The first aspect of claim 1, wherein the peeling force when peeling the first peeling layer is 0.15 N / 25 mm or less, and the peeling force when peeling the second peeling layer is 0.05 N / 25 mm or more. Laminated body. The laminate according to claim 1 or 2, wherein the thickness of the alignment layer contained in the first liquid crystal curing layer is 1/3 or less of the thickness of the alignment layer contained in the second liquid crystal alignment layer. The thickness of the alignment layer contained in the first liquid crystal curing layer is 10 nm to 500 nm, and the thickness of the alignment layer contained in the second liquid crystal alignment layer is 1 μm to 3.5 μm, claim 1 to 3. The laminate according to any one. The first liquid crystal cured layer and the second liquid crystal cured layer are a layer giving a phase difference of λ / 4 and a positive C layer, or a layer giving a phase difference of λ / 4 and a phase difference of λ / 2. The laminate according to any one of claims 1 to 4, which is a layer for giving. The laminate according to any one of claims 1 to 5, wherein the adhesive layer is an adhesive layer. An optical laminate containing a first liquid crystal cured layer, an adhesive layer, and a second liquid crystal cured layer in this order.
Both the first liquid crystal cured layer and the second liquid crystal cured layer include a layer containing a cured product of a polymerizable liquid crystal compound and an orientation layer.
Each of the first liquid crystal cured layer and the second liquid crystal cured layer uses a measurement sample in which a film forming the layer is bonded to a glued mount cut out in a square having a central portion of 30 mm × 30 mm, and has a tip diameter. A needle of 1 mm φ0.5 R is pierced perpendicularly to the surface of the film at a speed of 0.33 cm / sec, and the amount of displacement due to bending of the film in the piercing direction, which is measured when a break occurs, is the amount of strain. When S (mm) and the stress applied to the film are F (g), the formula (1):
Puncture elastic modulus (g / mm) = F (g) / S (mm) (1)
The puncture elastic modulus calculated by
The thickness of the alignment layer contained in the first liquid crystal cured layer is smaller than the thickness of the alignment layer contained in the second liquid crystal cured layer.
An optical laminate having a tensile elastic modulus of 1,000 N / mm ² or less. The optical laminate according to claim 7, wherein the thickness of the alignment layer contained in the first liquid crystal curing layer is 1/3 or less of the thickness of the alignment layer contained in the second liquid crystal alignment layer. The thickness of the alignment layer contained in the first liquid crystal curing layer is 10 nm to 500 nm, and the thickness of the alignment layer contained in the second liquid crystal alignment layer is 1 μm to 3.5 μm, claim 7 or 8. The laminate described.

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