JP7045511B1 - Laminate manufacturing method and laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a laminated body having a plurality of polymer layers and easily exhibiting different functions in each polymer layer. A method for producing a laminate including a first polymer layer and a second polymer layer laminated on the first polymer layer, wherein a first coating liquid forming the first polymer layer and the above-mentioned Using a second coating liquid that forms a second polymer layer, the second coating liquid directly coats the first coating liquid to form a coating liquid layer on the substrate. The first coating liquid contains a crosslinkable first polymer, the second coating liquid contains a crosslinkable second polymer, and the unit weight of the first polymer and the second polymer is unit mass. A method for producing a laminate, wherein the number of cross-linking points per unit is different, and each of the first polymer and the second polymer is cross-linked to form the first polymer layer and the second polymer layer. [Selection diagram] Fig. 1

Description

The present invention relates to a method for producing a laminated body and a laminated body.

Conventionally, a laminate having a plurality of polymer layers having different functions is known. For example, a polarizing film is applied to an image display unit of various image display devices, and the polarizing film is usually applied to the image display unit via an adhesive sheet. This type of adhesive sheet needs to have a plurality of functions such as an anchoring force for a polarizing film, an adhesive force for an image display unit, an appropriate refractive index and a hue for being applied to the image display unit, and the like. .. Therefore, the pressure-sensitive adhesive sheet is preferably a laminate having a plurality of polymer layers having different functions.

A wet-on-dry method is known as a method for producing such a laminated body. In the wet-on-dry method, the first coating liquid is applied onto the substrate and then dried and solidified to form the first polymer layer. Subsequently, a second coating liquid is applied onto the first polymer layer and then dried and solidified to form a second polymer layer. According to the wet-on-dry method, since each polymer layer is sequentially formed, it is easy to impart the intended function to each polymer layer. On the other hand, the laminate produced by the wet-on-dry method has a problem that each polymer layer is easily peeled off at these boundary surfaces. There is also the problem that the equipment becomes large.

The dry laminating method is also known. In the dry laminating method, a laminated body is manufactured by separately producing and laminating a first polymer layer and a second polymer layer in order to form a second polymer layer on a first polymer layer formed on a substrate. do. However, the laminate produced by this dry laminating method also has a problem that each polymer layer is easily peeled off at the boundary surface thereof, as in the wet-on-dry method.

Therefore, as another method, an attempt is made to produce a laminated body by a method called a wet-on-wet method. For example, in Patent Document 1, a first coating liquid and a second coating liquid containing a polymerizable monomer and a photopolymerization initiator are used, and the second coating liquid is directly applied on the first coating liquid. There has been proposed a method for manufacturing a laminate, which comprises a coating step of coating on a coating material and a step of irradiating each coated liquid with active energy rays. According to such a manufacturing method, by directly coating the second coating liquid on the first coating liquid, a clear boundary surface is not formed between the polymer layers, so that the peeling as described above is performed. Is suppressed. Further, by irradiating each coated liquid with active energy rays, a part of the monomer is polymerized and each coating liquid is gelled. As a result, the transfer of components between the coating liquids is suppressed, and it is said that each polymer layer easily exerts the intended function.

Japanese Unexamined Patent Publication No. 2017-185482

However, in the production method described in Patent Document 1, as described above, in order to form each polymer layer using a monomer having a relatively small molecular weight, an active energy ray is provided so as not to cause component transfer between the coating liquids. Irradiate to polymerize a part of the monomer. Therefore, the transfer of the monomer occurs between each coating liquid after the coating and before the irradiation with the active energy ray. Therefore, it becomes difficult for each polymer layer to fully exhibit the intended function.

On the other hand, if the functions of the respective polymer layers of the laminated body are to be different, the peeling of the other polymer layer from one polymer layer is likely to occur as described above.

In view of the above circumstances, the present invention relates to a method for producing a laminate having a plurality of polymer layers and easily exhibiting different functions in each polymer layer, and a laminate in which each polymer layer exhibits different functions and peeling is suppressed. The challenge is to provide the body.

The method for manufacturing a laminate according to the present invention is as follows.
A method for producing a laminate including a first polymer layer and a second polymer layer laminated on the first polymer layer.
Using the first coating liquid that forms the first polymer layer and the second coating liquid that forms the second polymer layer, the second coating liquid is directly applied onto the first coating liquid. A coating process for forming a coated coating liquid layer on a substrate is provided.
The first coating liquid contains a crosslinkable first polymer and contains.
The second coating liquid contains a crosslinkable second polymer and contains.
The number of cross-linking points per unit mass differs between the first polymer and the second polymer.
The first polymer and the second polymer are crosslinked to form the first polymer layer and the second polymer layer.

According to such a configuration, since the number of cross-linking points per unit mass differs between the first polymer and the second polymer, even if the cross-linking agent is transferred in each layer forming the coating liquid layer, these are cross-linked. The first polymer layer and the second polymer layer thus formed have different functions.

Further, the method for producing a laminate according to the present invention is preferably preferred.
At least one of the first coating liquid and the second coating liquid contains a cross-linking agent capable of cross-linking both the first polymer and the second polymer.

According to such a configuration, at least one of the coating liquids contains a cross-linking agent capable of cross-linking both the first polymer and the second polymer, thereby cross-linking each of the first polymer and the second polymer. A polymer layer and a second polymer layer can be formed.

Further, the method for producing a laminate according to the present invention is preferably preferred.
The molecular weights of the first polymer and the second polymer are 30,000 or more.

According to such a configuration, by setting the molecular weight of the polymer constituting each polymer layer to 30,000 or more, it becomes easy to maintain the separated state of each layer forming the coating liquid layer, and the first polymer layer and the first polymer layer and It becomes easy for the second polymer layer to exert different functions.

Further, the method for producing a laminate according to the present invention is preferably preferred.
The coating liquid layer has a first liquid layer formed by the first coating liquid and a second liquid layer formed by the second coating liquid.
The thickness of each of the first liquid layer and the second liquid layer before drying is 0.1 to 1,000 μm.

According to such a configuration, when the thickness of each of the first liquid layer and the second liquid layer before drying is 0.1 to 1,000 μm, it becomes easier for each polymer layer to exert different functions.

Further, the method for producing a laminate according to the present invention is preferably preferred.
The first polymer layer and the second polymer layer having different hardnesses are formed.

According to such a configuration, it is possible to produce an adhesive sheet suitable for an optical film, particularly a polarizing film, because the hardness of each polymer layer is different.

The laminate according to the present invention is
A first polymer layer and a second polymer layer laminated on the first polymer layer are provided.
The first polymer layer contains a first polymer having a cross-linking point.
The second polymer layer contains a second polymer having a cross-linking point.
The number of cross-linking points per unit mass differs between the first polymer and the second polymer.
An intermediate layer containing the first polymer and the second polymer is formed between the first polymer layer and the second polymer layer.
The thickness of the intermediate layer is 0.5 μm or more.

According to such a configuration, since the number of cross-linking points per unit mass is different between the first polymer and the second polymer, each polymer layer tends to exhibit a different function. Further, when the thickness of the intermediate layer between the first polymer layer and the second polymer layer is 0.5 μm or more, the peeling of the first polymer layer from the second polymer layer (in other words, from the first polymer layer). The peeling of the second polymer layer) is suppressed.

Further, the laminated body according to the present invention is preferably preferred.
The ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is 1.5 or more.

According to such a configuration, when the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is 1.5 or more, each polymer layer is more likely to exhibit a different function.

Further, the laminated body according to the present invention is preferably preferred.
The first polymer and the second polymer contain a polar group-containing monomer, and the first polymer and the second polymer contain a polar group-containing monomer.
The first polymer has a higher content of the polar group-containing monomer than the second polymer.
The mass ratio of the polar group-containing monomer to the total mass of the first polymer is 0.05 to 30%.
The mass ratio of the polar group-containing monomer to the total mass of the second polymer is 0.01 to 10%.

According to such a configuration, the first polymer has a higher content of the polar group-containing monomer than the second polymer, and the mass ratio of the polar group-containing monomer contained in the first polymer is 0.05 to 30%. Moreover, when the mass ratio of the polar group-containing monomer contained in the second polymer is 0.01 to 10%, each polymer layer is more likely to exhibit a different function.

Further, the laminated body according to the present invention is preferably preferred.
The first polymer layer and the second polymer layer have a cross-linked structure formed by a peroxide-based cross-linking agent.

According to such a configuration, each of the first polymer layer and the second polymer layer has a cross-linked structure formed by the peroxide-based cross-linking agent, so that each polymer layer can more easily exhibit different functions.

Further, the laminated body according to the present invention is preferably preferred.
The first polymer layer and the second polymer layer have a cross-linked structure formed by the peroxide-based cross-linking agent and the isocyanate-based cross-linking agent.

According to such a configuration, each of the first polymer layer and the second polymer layer has a cross-linked structure formed by a peroxide-based cross-linking agent and an isocyanate-based cross-linking agent, so that each polymer layer exerts a different function in particular. It becomes easier to do.

As described above, according to the present invention, a method for producing a laminate having a plurality of polymer layers and easily exhibiting different functions in each polymer layer, and a method in which each polymer layer exhibits different functions and peeling is suppressed. A laminate can be provided.

FIG. 1 is a schematic side view showing an application example of the laminated body according to one embodiment. FIG. 2 is a schematic view of a coating portion in a coating apparatus used in the method for manufacturing a laminated body according to an embodiment. FIG. 3 is a diagram showing a modified example of the coated portion of FIG. FIG. 4 is a schematic view of a coating portion in a coating apparatus used in the method for manufacturing a laminated body according to another embodiment. FIG. 5 is a diagram showing a modified example of the coated portion of FIG. FIG. 6 shows a frequency distribution diagram of a cross section of the laminate obtained by analysis with an atomic force microscope. FIG. 7 is a diagram for explaining a method of obtaining the thickness of the intermediate layer of the laminated body, and a profile is created based on the numerical values of the frequency distribution map of FIG. 6, and the range for obtaining an approximate expression in the profile is set. It is a figure explaining the method of specifying. FIG. 8 is a diagram for explaining a method of obtaining an approximate expression from the specified range of the profile of FIG. 7 and further obtaining the thickness of the intermediate layer based on the approximate expression. FIG. 9 is a graph for evaluating the peeling suppression of each pressure-sensitive adhesive sheet produced in the examples.

Hereinafter, a method for manufacturing a laminated body according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In this embodiment, as shown in FIG. 1, as the laminated body 10, an adhesive sheet for applying a polarizing film F as an optical film to a glass member G used for a display screen such as a liquid crystal screen is exemplified. However, the laminated body 10 is not limited to this application.

When the polarizing film F is applied to the glass member G via the pressure-sensitive adhesive sheet, it is usually required to maintain the quality of the pressure-sensitive adhesive sheet when the polarizing films F are bonded to each other and heat-treated. Specifically, if the adhesive sheet has a low hardness and is easily deformed, foaming is likely to occur between the adhesive sheet and the glass member G in the heat treatment, resulting in poor visibility (appearance). Become. Further, since the polarizing film F may shrink in the heat treatment, if the adhesive film has high hardness and is not easily deformed, the polarizing film F cannot be deformed according to the shrinkage, and the glass member G cannot be deformed. It becomes easy to peel off from.

As described above, suppressing foaming of the pressure-sensitive adhesive sheet during heat treatment and suppressing peeling of the pressure-sensitive adhesive sheet from the glass member G are contradictory (trade-off) issues. In designing the adhesive sheet, the hardness of the adhesive sheet is adjusted so as to suppress both foaming and peeling. However, when the heat treatment temperature is high or the shrinkage stress of the polarizing film F is large, the adhesive sheet is designed. It may be difficult to achieve both of these.

Therefore, the laminate of the present embodiment includes a first polymer layer and a second polymer layer laminated on the first polymer layer, and the number of cross-linking points of the first polymer layer and the second polymer layer is different. Therefore, the hardness of the second polymer layer is adjusted to be higher than that of the first polymer layer. This suppresses possible foaming between the high hardness second polymer layer and the glass member G, and alleviates the shrinkage stress of the polarizing film F due to the deformation of the low hardness first polymer layer. Thereby, the peeling that may occur between the second polymer layer and the glass member G is suppressed. Therefore, the laminate of the present embodiment is preferably an adhesive sheet having at least two layers having different hardnesses from each other.

More specifically, the pressure-sensitive adhesive sheet includes a first polymer layer 11 having a predetermined hardness, and a second polymer layer 12 laminated on the first polymer layer 11 and having a hardness higher than that of the first polymer layer 11. ing. When the pressure-sensitive adhesive sheet adheres the glass member G and the polarizing film F, the low-hardness first polymer layer 11 becomes a layer in contact with the surface of the polarizing film F, and the high-hardness second polymer layer 12 is the glass member G. It becomes a layer in contact with the surface of. That is, at the time of bonding, the first polymer layer 11 has a first bonding surface 111 in contact with the surface of the optical film F. Further, the second polymer layer 12 has a second adhesive surface 121 in contact with the surface of the glass member G. Further, the pressure-sensitive adhesive sheet has an intermediate layer 13 formed by the compatibility of the polymers of these layers between the first polymer layer 11 and the second polymer layer 12. The pressure-sensitive adhesive sheet has a hardness of the first polymer layer 11 lower than that of the second polymer layer 12, so that the first polymer layer 11 has a lower hardness than the second polymer layer 12 or the intermediate layer 13 in the heat treatment. Therefore, the edge of the first adhesive surface 111 is displaced inward with respect to the edge of the second polymer layer 12 or the intermediate layer 13. This misalignment is also called glue misalignment and is evaluated as the glue misalignment amount d. The pressure-sensitive adhesive sheet is preferably configured to form a predetermined amount of adhesive slippage. As a result, the pressure-sensitive adhesive sheet relieves the shrinkage stress of the polarizing film F in the heat treatment, so that peeling of the pressure-sensitive adhesive sheet from the polarizing film F is suppressed.

Further, the intermediate layer 13 is formed so as to have a thickness of a predetermined value or more. As a result, in the heat treatment, when stress is applied to the intermediate layer 13 and the peripheral portion due to the shrinkage of the first polymer layer 11, the first polymer layer 11 is peeled off from the second polymer layer 12 (in other words, in other words. Peeling of the second polymer layer 12 from the first polymer layer 11) is suppressed.

The method for producing the laminate 10 according to the present embodiment includes a preparatory step for preparing a first coating liquid 21 for forming the first polymer layer 11 and a second coating liquid 22 for forming the second polymer layer 12. The first coating liquid 21 that forms the 1 polymer layer 11 is applied onto the substrate (for example, on a release sheet such as a PET film called a separator), and the second coating liquid 22 that forms the second polymer layer 12 is formed. Is directly applied onto the first coating liquid 21 (that is, a wet-on-wet method is adopted), whereby the first coating liquid 21 and the second coating liquid 22 are coated on top of each other. It includes a coating step of forming the layer 20 and a drying step of drying and solidifying each coating liquid forming the coating liquid layer 20.

In the preparatory step, the first coating liquid 21 containing the first polymer that forms the first polymer layer 11 by cross-linking and the second polymer that forms the second polymer layer 12 by cross-linking are included. 2 Prepare the coating liquid 22. Further, it is important to select the first polymer and the second polymer so that the number of cross-linking points per unit mass differs between the first polymer and the second polymer. As a result, the laminated body 10 having different functions (specifically, hardness) between the first polymer layer 11 and the second polymer layer 12 can be manufactured.

The viscosities of the first coating liquid 21 and the second coating liquid 22 are preferably 0.0005 to 1,000 Pa · s. This makes it easier to maintain the separated state of the coating liquid layer 20 formed in the coating process. A solvent that can be mixed with each coating liquid can be used to adjust the viscosity. As the solvent, ethyl acetate, toluene, and a mixed solvent thereof are preferable. The viscosity shall be measured by a rheometer (manufactured by HAAKE). The measurement conditions are a shear rate of 1 [1 / s] and a temperature of 20 ° C.

The cross-linking point means a functional group that contributes to the cross-linking reaction of each of the first polymer and the second polymer. Further, the difference in the number of cross-linking points per unit mass between the first polymer and the second polymer means that the number of moles of functional groups per unit mass (mol / g) between the first polymer and the second polymer. ) Is different. In other words, it means that the mass (g / mol) at which the functional group is 1 mol is different between the first polymer and the second polymer. The number of moles of the functional group can be measured using an NMR device.

The first polymer and the second polymer may be any polymer that forms the first polymer layer 11 and the second polymer layer 12, respectively, by being crosslinked. Such a polymer may be, for example, a thermosetting polymer that is crosslinked by being heated to 100 ° C. or higher together with a crosslinking agent, and is a photocurable polymer that is crosslinked by irradiation with active energy rays such as ultraviolet rays. May be. The first polymer and the second polymer may be one of the thermosetting polymer and the other of the photocurable polymer, both of which are the thermosetting polymer or the photocurable polymer. May be.

The first coating liquid 21 and the second coating liquid 22 are preferably prepared so that the molecular weights of the first polymer and the second polymer are 30,000 or more. The lower limit of the molecular weight of each polymer is more preferably 500,000 or more, further preferably 1 million or more, and particularly preferably 1.5 million or more. The upper limit of the molecular weight of each polymer is preferably 3 million or less, more preferably 2.5 million or less. When the lower limit of the molecular weight is the above value, the cohesive force of the pressure-sensitive adhesive sheet becomes sufficient, and when the pressure-sensitive adhesive sheet is peeled off from the adherend such as the glass member G, the adhesive substance is attached to the adherend. Contamination of the adherend due to the residue is suppressed. On the other hand, when the upper limit of the molecular weight is as described above, the deterioration of the coatability due to the high viscosity of the first coating liquid 21 or the second coating liquid 22 is suppressed. The molecular weight means a weight average molecular weight. In addition, the weight average molecular weight can be measured by gel permeation chromatography (GPC). More specifically, the weight average molecular weight is converted from the measured value of standard polystyrene using, for example, the model name "HLC-8320GPC" (column: TSKgelGMH-H (S), manufactured by Tosoh Corporation) as the GPC device. Can be measured by.

The first polymer and the second polymer are preferably (meth) acrylic polymers or urethane-based polymers. In constructing the pressure-sensitive adhesive sheet, the (meth) acrylic polymer capable of forming a polymer layer having higher transparency is preferable. Further, the first polymer and the second polymer may be a silicone-based polymer or a rubber-based polymer.

The mass ratio of the first polymer or the second polymer to the total mass of the first coating liquid 21 or the second coating liquid 22 is preferably 0.1% or more.

The (meth) acrylic polymer contains an alkyl (meth) acrylate as a main component. In addition, (meth) acrylate means acrylate and / or methacrylate.

Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group and a decyl group. Examples thereof include a group, an isodecyl group, a dodecyl group, an isomyristyl group, a lauryl group, a tridecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group and an octadecyl group. The alkyl (meth) acrylate can be used alone or in combination of two or more. The average carbon number of the alkyl group is preferably 3 to 9.

The monomer constituting the (meth) acrylic polymer includes a group consisting of an aromatic ring-containing (meth) acrylate, an amide group-containing monomer, a carboxyl group-containing monomer, and a hydroxyl group-containing monomer, in addition to the alkyl (meth) acrylate. One or more copolymerization monomers selected may be mentioned. The copolymerizable monomer can be used alone or in combination of two or more.

The aromatic ring-containing (meth) acrylate is a compound having an aromatic ring structure in its structure and containing a (meth) acryloyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring, a biphenyl ring and the like. The aromatic ring-containing (meth) acrylate has the effect of adjusting the phase difference generated when stress is applied to the pressure-sensitive adhesive sheet due to the shrinkage of the optical film F, and suppresses light leakage generated by the shrinkage of the optical film F. can do.

Examples of the aromatic ring-containing (meth) acrylate include benzyl (meth) acrylate, phenyl (meth) acrylate, o-phenylphenol (meth) acrylate, phenoxy (meth) acrylate, phenoxyethyl (meth) acrylate, and phenoxypropyl (. Meta) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, ethylene oxide-modified cresol (meth) acrylate, phenolethylene oxide-modified (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate , Examples thereof include those having a naphthalene ring such as 2-naphthoxyethyl acrylate and 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate; those having a biphenyl ring such as biphenyl (meth) acrylate. Among these, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate are preferable from the viewpoint of improving the adhesive properties and durability of the pressure-sensitive adhesive sheet.

The amide group-containing monomer is a compound containing an amide group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Examples of the amide group-containing monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, N-methyl (meth) acrylamide, and N-. Butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, Mercaapto Acrylamide-based monomers such as methyl (meth) acrylamide and mercaptoethyl (meth) acrylamide; N-acrylloyl heterocyclic monomers such as N- (meth) acryloylmorpholin, N- (meth) acryloylpiperidin, and N- (meth) acryloylpyrrolidine; Examples thereof include N-vinyl group-containing lactam-based monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

The carboxyl group-containing monomer is a compound containing a carboxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like. Among these, acrylic acid is preferable from the viewpoint of improving the adhesive properties of the pressure-sensitive adhesive sheet.

The hydroxyl group-containing monomer is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl. Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylates, 10-hydroxydecyl (meth) acrylates and 12-hydroxylauryl (meth) acrylates; and (4-hydroxymethylcyclohexyl) -methyl acrylates. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable, and 4-hydroxybutyl (meth) acrylate is more preferable, from the viewpoint of improving the durability of the pressure-sensitive adhesive sheet.

When the (meth) acrylic polymer is used, the mass ratio of the monomers having an activating group for a cross-linking reaction such as a hydroxyl group, a carboxyl group, and an amide group (monomer containing a polar group) among the monomers constituting the polymer is appropriately adjusted. Thereby, the number of the cross-linking points can be changed. Further, it is preferable to appropriately change the mass ratio of the monomer so that the number of cross-linking points differs between the first polymer and the second polymer. More specifically, the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 1.5 or more, more preferably 2.0 or more. It is more preferably 3.0 or more, and even more preferably 4.0 or more. The ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 20 or less, more preferably 10 or less, and preferably 6.0 or less. More preferred. This facilitates that the first polymer layer 11 and the second polymer layer 12 perform different functions from each other. More specifically, the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is equal to or higher than the above value, whereby the first polymer layer 11 and the second polymer layer 12 are separated from each other. The difference in hardness becomes sufficient, foaming that may occur between the second polymer layer 12 and the glass member G is suppressed, and eventually peeling between the second polymer layer 12 and the glass member G is suppressed. Will be done. Further, when the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is equal to or less than the above value, the difference in hardness between the first polymer layer 11 and the second polymer layer 12 is increased. It does not become too large, foaming that may occur between the layers of the first polymer layer 11 and the second polymer layer 12 is suppressed, and peeling between the second polymer layer 12 and the glass member G is suppressed.

Further, the ratio is set as described above, the mass ratio of the monomer to the total mass of the first polymer is 0.05 to 30%, and the mass ratio of the monomer to the total mass of the second polymer is 0. It is preferably 01 to 10%. Further, when the pressure-sensitive adhesive sheet is produced, the mass ratio of the monomer to the total mass of the first polymer is 0.2 to 20%, and the mass ratio of the monomer to the total mass of the second polymer is 0. The mass ratio of the monomer to the total mass of the first polymer is preferably 0.3 to 10%, and the mass ratio of the monomer to the total mass of the second polymer is 0.1 to 5%. More preferably, it is 2%.

The weight average molecular weight of the (meth) acrylic polymer is preferably 30,000 or more. This makes it easier to maintain the separated state of the coating liquids of the coating liquid layer 20.

As the urethane-based polymer, it is preferable to use a urethane prepolymer which is a reaction product of a polyol and a polyisocyanate.

Examples of the polyol include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, castor oil-based polyols, and the like.

The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-butyl-2-ethyl-. 1,3-Propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2- Examples thereof include methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like.

Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, and 2-methyl-1. , 4-Cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, these acid anhydrides Things and the like can be mentioned.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like.

Examples of the polycaprolactone polyol include a caprolactone-based polyester diol obtained by ring-opening polymerization of a cyclic ester monomer such as ε-caprolactone and σ-valerolactone.

The polycarbonate polyol is, for example, a polycarbonate polyol obtained by subjecting the polyol component to a polycondensation reaction with phosgen; the polyol component and the polyol component, dimethyl carbonate, diethyl carbonate, diprovyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate. , Polycarbonate polyol obtained by ester exchange condensation with carbonic acid diesters such as propylene carbonate, diphenyl carbonate, dibenzyl carbonate; a copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; the various polycarbonate polyols and a carboxyl group. Polycarbonate polyol obtained by esterifying the contained compound; polycarbonate polyol obtained by etherifying the various polycarbonate polyols with the hydroxyl group-containing compound; obtained by performing an ester exchange reaction between the various polycarbonate polyols and the ester compound. Polycarbonate polyol; Polycarbonate polyol obtained by ester exchange reaction between the various polycarbonate polyols and a hydroxyl group-containing compound; Polycarbonate-based polycarbonate polyol obtained by a polycondensation reaction between the various polycarbonate polyols and a dicarboxylic acid compound; the various polycarbonates. Examples thereof include a copolymerized polyether polycarbonate polyol obtained by copolymerizing a polyol and an alkylene oxide.

Examples of the castor oil-based polyol include castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component. Specific examples thereof include castor oil-based polyols obtained by reacting castor oil fatty acid with polypropylene glycol.

Examples of the polyisocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates compounds and the like.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4. -Examples include trimethylhexamethylene diisocyanate.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentenediisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated triisocyanate. Range isocyanate Hydrogenated tetramethylxylylene diisocyanate and the like can be mentioned.

Examples of the aromatic polyisocyanate include phenylenediocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate. Examples thereof include 4,4'-toluene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalenediocyanate, and xylylene diisocyanate.

When the urethane prepolymer is used, the number of cross-linking points can be adjusted by appropriately adjusting the mass ratio of the monomer having an isocyanate group (activating group for the cross-linking reaction) (polar group-containing monomer) among the monomers constituting the prepolymer. Can be changed. Further, it is preferable to appropriately change the mass ratio of the monomer so that the number of cross-linking points differs between the first polymer and the second polymer. More specifically, the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 1.5 or more, more preferably 2.0 or more. It is more preferably 3.0 or more, and even more preferably 4.0 or more. The ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 20 or less, more preferably 10 or less, and preferably 6.0 or less. More preferred. This facilitates the first polymer layer and the second polymer layer to exert different functions from each other.

Further, the ratio is set as described above, the mass ratio of the monomer to the total mass of the first polymer is 0.05 to 30%, and the mass ratio of the monomer to the total mass of the second polymer is 0. It is preferably 01 to 10%. Further, when the pressure-sensitive adhesive sheet is produced, the mass ratio of the monomer to the total mass of the first polymer is 0.2 to 20%, and the mass ratio of the monomer to the total mass of the second polymer is 0. The mass ratio of the monomer to the total mass of the first polymer is preferably 0.3 to 10%, and the mass ratio of the monomer to the total mass of the second polymer is 0.1 to 5%. More preferably, it is 2%.

The weight average molecular weight of the urethane prepolymer is preferably 30,000 or more. This makes it easier to maintain the separated state of the coating liquids of the coating liquid layer 20.

As the cross-linking agent, an organic cross-linking agent, a polyfunctional metal chelate, or the like can be used. Examples of the organic cross-linking agent include isocyanate-based cross-linking agents, peroxide-based cross-linking agents, epoxy-based cross-linking agents, imine-based cross-linking agents and the like. The polyfunctional metal chelate is one in which a polyvalent metal is covalently bonded or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti and the like. Can be mentioned. Examples of the atom in the organic compound to be covalently bonded or coordinated are an oxygen atom and the like, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound and a ketone compound. The cross-linking agent can be used alone or in combination of two or more.

As the cross-linking agent, it is preferable to use at least one of the isocyanate-based cross-linking agent and the peroxide-based cross-linking agent, and it is more preferable to use the isocyanate-based cross-linking agent and the peroxide-based cross-linking agent in combination.

As the isocyanate-based cross-linking agent, a compound having at least two isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or a quantification agent) can be used. For example, the known aliphatic polyisocyanate, the alicyclic polyisocyanate, the aromatic polyisocyanate, etc., which are generally used for the urethanization reaction, are used.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4. -Examples include trimethylhexamethylene diisocyanate.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentenediisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated triisocyanate. Range isocyanate Hydrogenated tetramethylxylylene diisocyanate and the like can be mentioned.

Examples of the aromatic polyisocyanate include phenylenediocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate. Examples thereof include 4,4'-toluene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalenediocyanate, and xylylene diisocyanate.

The isocyanate-based cross-linking agent includes a multimer of diisocyanate (dimers, trimer, pentamer, etc.), a urethane-modified product obtained by reacting with a polyhydric alcohol such as trimethylolpropane, and a urea-modified product. Biuret-modified products, alphanate-modified products, isocyanate-modified products, carbodiimide-modified products and the like can also be used.

Examples of commercially available isocyanate-based cross-linking agents include the trade names "Millionate MT", "Millionate MTL", "Millionate MR-200", "Millionate MR-400", and "Coronate L" manufactured by Tosoh Corporation. , "Coronate HL", "Coronate HX", trade names "Takenate D-110N", "Takenate D-120N", "Takenate D-140N", "Takenate D-160N", "Takenate D-160N" manufactured by Mitsui Chemicals, Inc. Examples thereof include "Takenate D-165N", "Takenate D-170HN", "Takenate D-178N", "Takenate 500", and "Takenate 600".

As the isocyanate-based cross-linking agent, an aromatic polyisocyanate and an aromatic polyisocyanate compound which is a modified product thereof, an aliphatic polyisocyanate and an aliphatic polyisocyanate compound which is a modified product thereof are preferable. The aromatic polyisocyanate compound has a good balance between the crosslinking rate and the pot life and is preferably used. As the aromatic polyisocyanate compound, tolylene diisocyanate and a modified product thereof are particularly preferable.

The peroxide can be appropriately used as long as it generates radically active species by heating or light irradiation to promote cross-linking of the (meth) acrylic polymer, but in consideration of workability and stability. Therefore, it is preferable to use a peroxide having a half-life temperature of 80 ° C. to 160 ° C. for 1 minute, and more preferably to use a peroxide having a half-life temperature of 90 ° C. to 140 ° C.

Examples of the peroxide-based cross-linking agent include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.) and di (4-t-butylcyclohexyl) peroxydicarbonate (1). Minute half-life temperature: 92.1 ° C., di-sec-butylperoxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butylperoxyneodecanoate (1 minute half-life temperature: 103) .5 ° C), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide (1 minute half-life temperature: 110.3 ° C) 1 minute half temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130. 0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexyl peroxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) And so on. Among them, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) and dilauroyl peroxide (1 minute half-life temperature: 116.) Because of the excellent cross-linking reaction efficiency. 4 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C.) and the like are preferable.

The first polymer and the second polymer are preferably thermosetting polymers that are crosslinked by being heated with the crosslinking agent. In this case, the cross-linking agent may be contained in only one of the first coating liquid and the second coating liquid. In the present embodiment, as described above, the number of cross-linking points per unit mass differs between the first polymer and the second polymer, but in the coating process, the wet-on-wet method is adopted for each coating. Since the working liquid is applied, transfer of the cross-linking agent may occur in each layer of the coating liquid layer 20 from the coating step to the drying step. Therefore, if the cross-linking agent is contained in only one of the first coating liquid 21 and the second coating liquid 22, the cross-linking reaction of each polymer can sufficiently proceed. Further, by including the cross-linking agent in only one of the first coating liquid 21 and the second coating liquid 22, the concentration gradient of the cross-linking agent becomes large, and the transfer amount thereof also becomes large. Further, by adjusting the difference in the number of cross-linking points, the characteristics of each polymer layer can be further controlled.

Further, both the first coating liquid 21 and the second coating liquid 22 may contain the cross-linking agent. In this case, the coating liquid having less cross-linking points may contain more of the cross-linking agent, and the coating liquid having more cross-linking points may contain less of the cross-linking agent, or the cross-linking agent may be contained. The coating liquid having less cross-linking points may contain less of the cross-linking agent, and the coating liquid having more cross-linking agents may contain more of the cross-linking agent.

When the components of the monomers are the same in the first polymer and the second polymer, the content of the cross-linking agent may be 0.01 to 30 parts by mass with respect to 100 parts by mass of the total mass of each polymer. preferable. Further, when different kinds of the cross-linking agent are required due to the difference in the monomer components between the first polymer and the second polymer, the content of each cross-linking agent is the mass of the polymer capable of reacting with these 100. It is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 2 parts by mass with respect to parts by mass.

Further, at least one of the first coating liquid 21 and the second coating liquid 22 may contain a catalyst that promotes the reaction between the first polymer and the second polymer and the cross-linking agent. Examples of the catalyst include organometallic catalysts.

In the coating step, it is preferable to use a coating device provided with a coating portion called a die coater as shown in FIGS. 2 to 3. The die coater A of the present embodiment includes a plurality of dies a having slots for discharging the coating liquid. The die a is a PET film P supported by the roller member b, and the PET film P traveling so as to be close to the opening of the slot is coated with the coating liquid discharged from the slot to coat the PET film. It is configured to form a coating film on the surface of P. The die coater A is a first die a1 that coats the PET film P with the first coating liquid 21, and a second die that directly coats the second coating liquid 22 on the first coating liquid 21. It is equipped with a2. The first die a1 and the second die a2 are arranged at intervals along the circumferential direction of the roller member b, so that after a certain period of time has elapsed after the first coating liquid 21 has been applied. The second coating liquid 22 may be configured to be coated (FIG. 2). Further, the first die a1 and the second die a2 may be configured to apply the coating liquid to be applied to the PET film P at the same time (FIG. 3). The direction of the die a is not limited to the mode shown in FIGS. 2 to 3, and may be arranged so as to be inclined with respect to the horizontal direction, for example. In addition to the die coater, a bar coater, a gravure coater, a tension web coater, or the like may be combined.

In the coating step, each coating liquid is coated so that the first coating liquid 21 and the second coating liquid 22 form a coating liquid layer 20 separated from each other.

In order to impart different functions to each polymer layer, the first polymer and the second polymer may be in a state of being separated from each other in the coating liquid layer 20, and a clear boundary surface may not be formed. Components having a relatively low molecular weight, such as the cross-linking agent and the solvent, which can be contained in each coating liquid, may be diffused into each layer.

The flow rate of the coating liquid discharged from the die a is preferably set so that the coating liquid layer 20 can be easily maintained. For example, the thickness of the first liquid layer formed by the first coating liquid 21 and the second liquid layer formed by the second coating liquid 22 constituting the coating liquid layer 20 before drying. It is preferable to adjust the flow rate so that the value is 0.1 to 1,000 μm. Further, it is preferable that the flow rate is constant so that the thickness of each polymer layer becomes uniform. The constant flow rate of the coating liquid means that the value calculated by [maximum flow rate-minimum flow rate] / average flow rate is 0.2 or less, preferably 0.1 or less during steady operation. do. Further, the flow rate shall mean a mass flow rate.

The thickness of the first liquid layer and the second liquid layer means the average thickness. The average thickness can be obtained by measuring the thickness of each liquid layer at arbitrary 50 points on the side end surface of the coating liquid layer 20 and arithmetically averaging them.

In the drying step, the first polymer and the second polymer are crosslinked by the drying portion installed on the downstream side of the coating portion. In the drying step, each polymer may be crosslinked with the cross-linking agent depending on the type of the polymer contained in each coating liquid, or each polymer may be cross-linked by irradiating with active energy rays such as ultraviolet rays. good. In other words, the dried portion may have a heating portion for cross-linking the thermosetting polymer, or may have a light irradiation portion for cross-linking the photocurable polymer. The temperature of the heating unit is usually set to 50 to 160 ° C.

When the cross-linking agent is used, mutual component transfer to each layer in the coating liquid layer 20 by adopting the wet-on-wet method may be positively utilized. For example, the cross-linking agent is excessively contained in one of the first coating liquid 21 and the second coating liquid 22, and the cross-linking agent is transferred to the other coating liquid during the cross-linking reaction. You may. This will be described by way of exemplifying the production of the pressure-sensitive adhesive sheet. In this case, the first coating liquid 21 is set so that the number of the cross-linking points per unit mass is larger than that of the second coating liquid 22, but in addition to this, the first coating liquid 21 is set. When the cross-linking agent is contained only (or when the content of the cross-linking agent is larger in the first coating liquid 21 than in the second coating liquid 22), the coating liquid layer 20 A concentration gradient of the cross-linking agent is generated between the layers. That is, a high-concentration layer having a relatively high cross-linking agent concentration (the first liquid layer formed by the first coating liquid 21) and a low-concentration layer having a relatively low cross-linking agent concentration (second coating liquid 22). The second liquid layer) formed by the above is formed. As a result, the high-concentration layer, that is, the layer having a large number of cross-linking points (in other words, the layer to be the first polymer layer 11) is rapidly cross-linked, and after the cross-linking agent is transferred from the high-concentration layer to the low-concentration layer. , The cross-linking of the low concentration layer (in other words, the layer to be the second polymer layer 12) is completed to form the second polymer layer 12. As described above, after the formation of the first polymer layer 11 having more cross-linking points, the second polymer layer 12 having fewer cross-linking points is formed. Therefore, the hardness of the first polymer layer 11 and the second polymer layer 12 further increases the hardness. It has the advantage of being able to make a difference. That is, the functions of the first polymer layer 11 and the second polymer layer 12 can be significantly different from each other.

In the drying step, drying for removing the solvent may be performed at the same time as the cross-linking of each polymer or after the cross-linking of each polymer.

Next, the laminated body 10 according to the embodiment manufactured by the above manufacturing method will be described in more detail.

As shown in FIG. 1, the laminate 10 according to the present embodiment includes a first polymer layer 11 containing the first polymer and a second polymer layer 12 laminated on the first polymer layer 11 and containing the second polymer. It is equipped with. In other words, the first polymer layer 11 is formed by the first polymer cross-linked with the cross-linking agent. Further, the second polymer layer 12 is formed by the second polymer cross-linked with the cross-linking agent.

The thickness of the laminate 10 is usually 3 to 1000 μm. The thickness of the laminated body 10 means the average thickness. The average thickness can be obtained by measuring the thicknesses of the laminated body 10 at arbitrary 50 points in the length direction (MD) and arithmetically averaging them.

The laminate 10 has an intermediate layer 13 formed between the first polymer layer 11 and the second polymer layer 12. The intermediate layer 13 includes the first polymer and the second polymer. The intermediate layer 13 is formed of the first polymer cross-linked with the cross-linking agent and the second polymer cross-linked with the cross-linking agent. The intermediate layer 13 contains a polymer in which the first polymers are crosslinked, a polymer in which the second polymers are crosslinked, and a polymer in which the first polymer and the second polymer are crosslinked. May be good.

It is important that the thickness of the intermediate layer 13 is 0.5 μm or more. As a result, in the intermediate layer 13, the first polymer and the second polymer are entangled with each other and / or crosslinked with each other, whereby the first polymer layer and the second polymer layer are adhered to each other. It is thought to improve sex. This suppresses the peeling of the first polymer layer 11 from the second polymer layer 12 (in other words, the peeling of the second polymer layer 12 from the first polymer layer 11). On the other hand, if the thickness of the intermediate layer is less than 0.5 μm, peeling is likely to occur between the first polymer layer and the second polymer layer, or the first polymer layer and the second polymer are likely to peel off. Foaming is likely to occur between the layers. The thickness of the intermediate layer 13 can be measured using an atomic force microscope (AFM) as described in Examples.

The thickness of the intermediate layer 13 is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 2 μm or less. This facilitates each of the first polymer layer 11 and the second polymer layer 12 to exert different functions. More specifically, the difference in hardness between the first polymer layer 11 and the second polymer layer 12 becomes remarkable. From this viewpoint, the thickness of the intermediate layer 13 is preferably 50% or less, more preferably 25% or less, still more preferably 20% or less, based on the thickness of the laminated body 10. It is more preferably% or less, and even more preferably 5% or less.

In the laminate 10 of the present embodiment, the second polymer layer 12 has a higher hardness than the first polymer layer 11, whereby when the optical film F and the glass member G are adhered to each other, the laminate 10 has a higher hardness. It is configured to form the glue slip. Further, by adhering the second polymer layer 12 having a relatively high hardness to the surface of the glass member G, foaming that may occur between the laminate 10 and the glass member G is suppressed, and the appearance is deteriorated. It is suppressed.

In the laminated body 10, the number of cross-linking points per unit mass is different between the first polymer layer 11 and the second polymer layer 12. The cross-linking point in the first polymer layer 11 means the cross-linking point possessed by the first polymer. That is, the cross-linking point in the first polymer layer 11 includes the cross-linking point of the first polymer cross-linked with the cross-linking agent and the cross-linking point of the first polymer remaining without contributing to the cross-linking reaction. Similarly, the cross-linking point in the second polymer layer 12 means the cross-linking point possessed by the second polymer. That is, the cross-linking point in the second polymer layer 12 includes a cross-linking point of the second polymer that contributes to the cross-linking reaction and forms a cross-linking structure, and a cross-linking point of the second polymer that remains without contributing to the cross-linking reaction. ..

As described above, the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 1.5 or more, more preferably 2.0 or more. It is more preferably 9.0 or more, and even more preferably 4.0 or more. The ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is preferably 20 or less, more preferably 10 or less, and preferably 6.0 or less. More preferred. This makes it easier for the first polymer layer 11 and the second polymer layer 12 to perform different functions from each other.

Further, it is preferable that the content of the polar group-containing monomer of the first polymer is higher than the content of the polar group-containing monomer of the second polymer. Then, the mass ratio of the polar group-containing monomer to the total mass of the first polymer is 0.05 to 30%, and the mass ratio of the polar group-containing monomer to the total mass of the second polymer is 0.01 to. It is more preferably 10%, and the mass ratio of the polar group-containing monomer to the total mass of the first polymer is 0.2 to 20%, and the mass ratio of the polar group-containing monomer to the total mass of the second polymer. Is more preferably 0.05 to 5%, the mass ratio of the monomer to the total mass of the first polymer is 0.3 to 10%, and the mass ratio of the monomer to the total mass of the second polymer is. It is more preferably 0.1 to 2%. This makes it easier for the first polymer layer 11 and the second polymer layer 12 to exert different functions as described above.

Further, it is preferable that each of the first polymer layer 11 and the second polymer layer 12 has a cross-linking structure formed by either the isocyanate-based cross-linking agent or the peroxide-based cross-linking agent, and the isocyanate-based cross-linking is preferable. It is more preferable to include both a cross-linked structure formed by the agent and a cross-linked structure formed by the peroxide-based cross-linking agent. This makes it easier for the first polymer layer 11 and the second polymer layer 12 to exert different functions from each other.

The cross-linked structure formed by the isocyanate-based cross-linking agent has a urethane bond formed by reacting the isocyanate group derived from the isocyanate-based cross-linking agent with the hydroxyl group of the polar group-containing monomer. Further, the cross-linked structure formed by the peroxide-based cross-linking agent has, for example, a carbon-carbon covalent bond in which the (meth) acrylic polymers are cross-linked by the peroxide-based cross-linking agent.

According to the laminated body 10 having the above configuration, the hardness (function) of the first polymer layer 11 and the second polymer layer 12 are clearly different from each other, so that peeling from the glass member G and the polarizing film F is suppressed. Will be done. More specifically, since the first polymer layer 11 has a lower hardness than the second polymer layer 12, when the heat treatment is performed after the first polymer layer 11 is adhered to the polarizing film F, the first polymer layer 11 is the polarizing film F. Since it can be shrunk at the same time, peeling of the laminated body 10 from the polarizing film F is suppressed. Further, since the second polymer layer 12 has a higher hardness than the first polymer layer 11, the second polymer layer 12 and the surface of the glass member G are subjected to the heat treatment after being adhered to the glass member G. Foaming is less likely to occur between them, whereby peeling of the laminate 10 from the glass member G is suppressed. As described above, in the laminated body 10 having the above structure, both delamination of the first polymer layer 11 and the second polymer layer 12 and peeling from other members such as the glass member G and the polarizing film F are suppressed. It becomes.

The method for producing the laminated body and the laminated body according to the present invention are not limited to the above-described embodiment. Further, the method for producing a laminated body and the laminated body according to the present invention are not limited by the above-mentioned effects. The method for producing the laminate and the laminate according to the present invention can be variously modified without departing from the gist of the present invention.

For example, in the above embodiment, the laminate 10 having two polymer layers has been exemplified, but the laminate is not limited to this, and the laminate of the present invention includes three or more polymer layers 21, 22, and 23. May be good. In this case, it is preferable that the hardness is gradually increased (or decreased) from the polymer layer 21 to the polymer layer 23. Along with this, the die coater A may have three or more dies a1, a2, and a3 (FIGS. 4 and 5).

Further, the laminate of the present invention is used for adhering the polarizing film F and the polarizing element protective film that protects the polarizing film F, or other optical films such as the polarizing film F, the retardation film, the surface treatment film, and the brightness improving film. May be done.

Hereinafter, the present invention will be further described by showing examples.

In this example, pressure-sensitive adhesive sheets in which the hardness of each polymer layer was variously changed were produced, and each pressure-sensitive adhesive sheet was evaluated.

[Example 1]
A copolymer of butyl acrylate (BA) and hydroxybutyl acrylate (HBA) as the first polymer (weight average molecular weight 700,000, mass ratio of HBA 5%), and butyl acrylate (BA) and hydroxybutyl acrylate as the second polymer. A copolymer with (HBA) (weight average molecular weight 700,000, mass ratio of HBA 1%) and an isocyanate-based cross-linking agent (Takenate D110N manufactured by Mitsui Kagaku Co., Ltd.) were prepared. Next, the first coating liquid was prepared by mixing 0.35 parts by mass of the cross-linking agent with 100 parts by mass of the first polymer (viscosity 6.3 Pa · s). Further, a second coating liquid was prepared by mixing 0.35 parts by mass of the cross-linking agent with 100 parts by mass of the second polymer (viscosity 6.3 Pa · s). Using each of the prepared coating liquids and a bar coater as the coating portion, a wet-on-wet method (WoW) was adopted to form a coating liquid layer on a separator (PET film) as a base material. The first polymer layer and the second polymer layer were formed by drying and curing the coating liquid layer at a temperature of 155 ° C. for 3 minutes using a heating device to obtain the pressure-sensitive adhesive sheet of Example 1 (Table 1). Details of manufacturing conditions are shown).

[Examples 2 to 6]
As shown in Table 2, the pressure-sensitive adhesive sheets of Examples 2 to 6 were prepared in the same manner as in Example 1 except that the first polymer, the second polymer, and the cross-linking agent were variously changed. In Table 2, ACMO used in the preparation of Examples 4 to 6 means N-acryloylmorpholine, AA means acrylic acid, PEA means phenoxyethyl acrylate, and NVP means N-vinylpyrrolidone.

[Comparative Examples 1 and 2]
As shown in Table 2, a single-layer pressure-sensitive adhesive sheet was prepared using only the second polymer in Example 1. The other manufacturing conditions were the same as in Example 1.

[Comparative Example 3]
As shown in Table 2, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 4 except that the dry-on-dry method (DoD) was adopted as the production method.

[Comparative Example 4]
As shown in Table 2, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 4 except that the wet-on-dry method (WoD) was adopted as the production method.

[Measurement of thickness of intermediate layer]
The pressure-sensitive adhesive sheets of Examples and Comparative Examples were cut in the thickness direction with a frozen ultramicrotome to prepare ultrathin sections of the pressure-sensitive adhesive sheet. The ultrathin section was placed on a silicon wafer, and AM-FM viscoelastic mapping measurement was performed using an atomic force microscope (AFM) under the following measurement conditions. A probe was scanned over the cross section of the pressure-sensitive adhesive sheet to measure the change in frequency near the interface between the first polymer layer and the second polymer layer. As an example, FIG. 6 shows a frequency distribution map of Example 2. In the frequency distribution map, the horizontal axis indicates the position of the adhesive sheet in the thickness direction, and the vertical axis indicates the position of the adhesive sheet in the length direction (MD). From the frequency distribution map, relatively small frequency shifts are observed in the cross section of the second polymer layer with high hardness, relatively large frequency shifts are observed in the cross section of the first polymer layer with low hardness, and these are observed in the cross section of the intermediate layer. It can be seen that the frequency shift between them was observed.
Next, the profile is created by extracting the data at an arbitrary position in the length direction (MD) from the frequency distribution map and plotting the extracted data on a graph having a vertical axis indicating the thickness and a horizontal axis indicating the frequency. Obtained. As an example, FIG. 7 shows the profile of Example 2.
Next, as shown in FIG. 7, in each graph, a first straight line parallel to the horizontal axis and passing through the minimum frequency and a second straight line parallel to the horizontal axis and passing through the maximum frequency are drawn. Further, the median values of the minimum frequency (frequency of the first straight line) and the maximum frequency (frequency of the second straight line) were obtained. Moreover, the frequency difference between the maximum frequency and the minimum frequency was obtained. Subsequently, in order to specify the range for obtaining the approximate expression in the profile, a first designated straight line parallel to the horizontal axis is drawn at a position of -25% of the frequency difference with respect to the median, and the frequency is with reference to the median. A second designated straight line parallel to the horizontal axis was drawn at the position of + 25% of the difference. Then, the profile between the intersection located on the first polymer layer side of the intersections of the first designated straight line and the profile and the intersection located on the second polymer layer side of the intersections of the second designated straight line and the profile is formed. An approximate expression was obtained from the extracted profile by the minimum square method.
Next, as shown in FIG. 8, a straight line showing an approximate expression was drawn in a graph. Then, the thickness of the intermediate layer was calculated from the difference in the thickness values at the intersections of the straight line showing the approximate expression and each of the first straight line and the second straight line.
From the frequency distribution map, 10 profiles were created at intervals of 0.7 μm in the length direction (MD), the thickness of the intermediate layer was obtained from each profile, and the median value of the thickness data of the total of 10 intermediate layers was used. The thickness of the intermediate layer of the adhesive sheet was used. The results are shown in Table 2.
(AFM measurement conditions)
Equipment: Oxford Instruments MFP-3D-SA
Measurement mode: AM-FM viscoelastic mapping mode Probe: Made of Si (spring constant 3N / m equivalent)
Measurement atmosphere: Atmospheric measurement temperature: 25 ° C
Measurement range: 8 μm square scan

[Preparation of polarizing film]
A polyvinyl alcohol film having a thickness of 45 μm was stretched up to 3 times while being dyed in an iodine solution having a concentration of 0.3% at 30 ° C. for 1 minute between rolls having different speed ratios. Then, the total stretch ratio was stretched to 6 times while being immersed in an aqueous solution containing boric acid at 60 ° C. and a concentration of 4% and potassium iodide at a concentration of 10% for 0.5 minutes. Then, it was washed by immersing it in an aqueous solution containing potassium iodide having a concentration of 1.5% at 30 ° C. for 10 seconds, and then dried at 50 ° C. for 4 minutes to obtain a polarizing element having a thickness of 18 μm. A 40 μm TAC film with HC that had been saponified was bonded to one side of the polarizing element, and a 17 μm cycloolefin-based film was bonded to the other side with a polyvinyl alcohol-based adhesive to prepare a polarizing film.

[Evaluation method 1: Delamination suppression based on stress relaxation and heating durability]
The cycloolefin-based film of the polarizing film prepared above was bonded to both sides of the pressure-sensitive adhesive sheet obtained above to prepare a polarizing film with an adhesive layer. A test piece (size 100 mm × 100 mm) was cut out from the polarizing film with an adhesive layer, the separator was peeled off, and then the adhesive layer was attached to non-alkali glass (Eagle XG manufactured by Corning Inc.). After autoclaving at 50 ° C. and 5 atm for 15 minutes, the mixture was subjected to heat treatment at 105 ° C. for 24 hours, and the size of foaming between the glass member and the adhesive sheet was measured. The adhesive sheet having a foam size of 100 μm or less was evaluated as having a good appearance. In addition, the presence or absence of peeling of the pressure-sensitive adhesive sheet from the glass member or the polarizing film and the presence or absence of delamination between the first polymer layer and the second polymer layer were observed. Further, the amount of glue slippage of the first polymer layer was measured. The pressure-sensitive adhesive sheet having an amount of glue slippage of 250 μm or more was evaluated as good. The results are shown in Table 2 and FIG.

As shown in Table 2 and FIG. 9, the pressure-sensitive adhesive sheets of Examples 1 to 6 were relatively suppressed in foaming and formed sufficient adhesive slippage. Further, when the pressure-sensitive adhesive sheets of Examples 1 to 6 were used, peeling of the glass member and the polarizing film was not observed. Furthermore, when the pressure-sensitive adhesive sheets of Examples 1 to 6 were used, delamination of the first polymer layer and the second polymer layer was not observed.

[Evaluation method 2: Transition of cross-linking agent]
For the pressure-sensitive adhesive sheet of Example 1, the content of the cross-linking agent contained in each of the first polymer layer and the second polymer layer was measured by total nitrogen analysis using TN2100 manufactured by Mitsubishi Seiko Analytech. As a result, the content of the cross-linking agent with respect to 100 parts by mass of all the polymers constituting the pressure-sensitive adhesive sheet was 0.74 parts by mass in the first polymer layer and 0.15 parts by mass in the second polymer layer. Therefore, it was confirmed that the cross-linking agent was transferred from the time of coating to the time of drying. Further, it can be seen that the hardness of the first polymer layer is higher than that of the second polymer layer because of the content of such a cross-linking agent.
The content of the cross-linking agent in Comparative Examples 1 and 2 was 0.3 parts by mass.

10: Laminate, 11: First polymer layer, 111: First adhesive surface, 12: Second polymer layer, 121: Second adhesive surface, 20: Coating liquid layer, 21: First coating liquid, 22: 2nd coating liquid, F: polarizing film, G: glass member, d: amount of glue misalignment, a1: 1st die, a11: slot, a2: 2nd die, a21: slot, a3: 3rd die , B: Roller member, P: PET film

Claims (8)

A method for producing a laminate including a first polymer layer and a second polymer layer laminated on the first polymer layer.
Using the first coating liquid that forms the first polymer layer and the second coating liquid that forms the second polymer layer, the second coating liquid is directly applied onto the first coating liquid. A coating process for forming a coated coating liquid layer on a substrate is provided.
The first coating liquid contains a crosslinkable first polymer and contains.
The second coating liquid contains a crosslinkable second polymer and contains.
The number of cross-linking points per unit mass differs between the first polymer and the second polymer, and the ratio of the number of cross-linking points of the first polymer to the number of cross-linking points of the second polymer is 1.5 or more. ,
A method for producing a laminate, wherein each of the first polymer and the second polymer is crosslinked to form the first polymer layer and the second polymer layer. The laminate has an intermediate layer containing the first polymer and the second polymer between the first polymer layer and the second polymer layer.
The method for producing a laminate according to claim 1, wherein the thickness of the intermediate layer is 0.5 to 4.2 μm. The method for manufacturing a laminate according to claim 1 or 2, wherein the laminate is an adhesive sheet. The method for producing a laminate according to any one of claims 1 to 3, wherein the first polymer and the second polymer are an acrylic polymer or a urethane polymer. The invention according to any one of claims 1 to 4 , wherein at least one of the first coating liquid and the second coating liquid contains a cross-linking agent capable of cross-linking both the first polymer and the second polymer. Method of manufacturing a laminate of. The method for producing a laminate according to any one of claims 1 to 5, wherein the first polymer and the second polymer have a molecular weight of 30,000 or more. The coating liquid layer has a first liquid layer formed by the first coating liquid and a second liquid layer formed by the second coating liquid.
The method for producing a laminate according to any one of claims 1 to 6 , wherein the thickness of each of the first liquid layer and the second liquid layer before drying is 0.1 to 1,000 μm. The method for producing a laminate according to any one of claims 1 to 7 , wherein the first polymer layer and the second polymer layer having different hardnesses are formed.

Images