resin laminate

Abstract

The present invention provides a resin laminate with excellent scratch resistance, adhesion, impact resistance, warp resistance, heat resistance, and transparency. [Solution] The resin laminate comprises a mixed layer 5 between a layer 6 of cured film and a layer 4 of resin substrate. The mixed layer is formed by mixing components of the cured film with a resin substrate forming composition. The cured film contains structural units derived from an isocyanurate skeleton, and the resin substrate contains 60% by mass or more of structural units derived from methyl methacrylate, and 0.5% by mass or more and 40% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule.

Description

[Technical Field]

[0001] This invention relates to a resin laminate. [Background technology]

[0002] Glass or transparent resin plates are used for the front panels of personal computers and LCD televisions to protect their surfaces. Recently, the use of resin plates for the front panels of touch-panel displays in smartphones and tablet computers is being considered.

[0003] Traditionally, glass panels, known for their scratch resistance, have been used for display front panels. However, glass panels are prone to breakage and have low impact resistance. Therefore, the use of resin panels, which offer excellent transparency, lightweight design, and processability, for display front panels is being considered. Transparent resin materials used for display front panels require scratch resistance and impact resistance, as they may be scratched or cracked due to contact with people or objects. Furthermore, transparent resin materials used for display front panels are also required to suppress warping caused by heat from the device or operating environment, and the resin itself must have excellent heat resistance.

[0004] Regarding the scratch resistance of resin sheets, Patent Document 1 discloses a resin laminate in which a cured film of a curable resin composition containing a specific polyfunctional monomer is formed on the surface of an acrylic resin sheet. Regarding the heat resistance of resin plates, Patent Document 2 discloses a polymerizable composition for touch panels containing a specific alkyl methacrylate and a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups in its molecule. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-30169 [Patent Document 2] Japanese Patent Publication No. 2006-306951 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, while the technology disclosed in Patent Document 1 has excellent surface scratch resistance, when directly bonded to a device and used as a faceplate, the heat from the device is directly transferred to the faceplate, making it prone to warping due to heat. Furthermore, if intended for use in environments exposed to high temperature atmospheres, such as automotive display faceplates, the resin itself also needs to have high heat resistance. In the technology disclosed in Patent Document 2, although the resin has excellent heat resistance, the scratch resistance of the resin surface after curing is insufficient because there is no cured coating. Even if a cured coating is added to the technology disclosed in Patent Document 2, the adhesion between the resin substrate and the cured coating is insufficient.

[0007] The present invention provides a resin laminate with excellent scratch resistance, adhesion, impact resistance, warp resistance, heat resistance, and transparency. [Means for solving the problem]

[0008] The gist of the present invention relates to a sheet-like resin laminate having a cured coating on at least one surface of a resin substrate. The resin laminate further comprises a mixed layer between the cured coating and the resin substrate. The mixed layer is formed by mixing the components of the cured film and the resin substrate forming composition that forms the resin substrate with each other. The cured film contains structural units derived from an isocyanurate skeleton represented by the following formula (1): The resin substrate contains 60% by mass or more of structural units derived from methyl methacrylate, and 0.5% by mass or more and 40% by mass or less of structural units derived from polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule.

[0009] [ka]

[0010] In formula (1), R 1 is each independently a divalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and the three * each indicate a bonding position. [Advantages of the Invention]

[0011] According to the present invention, a resin laminate excellent in scratch resistance, adhesion, impact resistance, warp resistance, heat resistance and transparency is provided. [Brief Description of the Drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a resin laminate in which a cured film is laminated on one side of a resin substrate. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of a resin laminate in which a cured film is laminated on both sides of a resin substrate. [Figure 3] FIG. 3 is an observation image of a transmission electron microscope for a small piece cut out from a cut surface of the resin laminate obtained in Example 1. FIG. 3 is an example of an observation image of a three-layer structure of a resin substrate layer / mixed layer / cured film layer. [Figure 4] FIG. 4 is an observation image of a transmission electron microscope for a small piece cut out from a cut surface of the resin laminate obtained in Comparative Example 4. FIG. 4 is an example of an observation image when no mixed layer is observed between the resin substrate layer and the cured film layer. [Embodiments for Carrying Out the Invention]

[0013] [Explanation of Terms] The meanings of the terms are as follows. “(meth)acrylate” is a general term for acrylate and methacrylate. “(meth)acrylic acid” is a general term for acrylic acid and methacrylic acid. “Monomer” means an unpolymerized compound. "Repeating unit" means a unit derived from the monomer formed by polymerization of the monomer. The repeating unit may be a unit directly formed by a polymerization reaction, or a unit in which a part of the unit is converted into another structure by treating the polymer. "Mass %" indicates the content ratio of a predetermined component contained when the total amount is 100 mass %, unless otherwise specified.

[0014] Hereinafter, some embodiments will be described with reference to the drawings as necessary. However, the following description relates to representative examples, and the present invention is not limited to the following description. The dimensional ratios in each drawing are for convenience of explanation and are different from the actual ones. In the following drawings, the same components are denoted by the same reference numerals, and the description of overlapping components may be omitted.

[0015] [Resin laminate] The resin laminate of the present invention is a sheet-like resin laminate provided with a cured film on at least one of the two surfaces (front and back surfaces) of the resin substrate. As exemplarily shown in FIG. 1, the resin laminate 3 may have a cured film 1 on one side of the resin substrate 2, or as exemplarily shown in FIG. 2, the resin laminate 3 may have cured films 1 on both sides of the resin substrate 2, and is not particularly limited.

[0016] It is preferable that the resin laminate has a cured film on 80% or more of the surface of the resin substrate, more preferably 90% or more of the surface of the resin substrate, and most preferably the entire surface of the resin substrate.

[0017] The resin laminate of the present invention further includes a mixed layer formed by mixing the components of the cured film and the composition for forming the resin substrate between the cured film and the resin substrate. Details of the mixed layer will be described later.

[0018] A suitable resin laminate may satisfy both of the following condition A and the following condition B. Condition A: 12 μm ≤ At ≤ 40 μm Condition B: 0.002≦(Bt / At)≦0.3 However, At is the thickness of the cured film, and Bt is the thickness of the mixed layer (μm) measured by the method 1 below. Method 1: The resin laminate is cut perpendicular to the main surface, and then a small piece for transmission electron microscopy is cut from the cut surface using a microtome. An observation image of the cross-section of the cut piece is obtained using a transmission electron microscope. In the obtained observation image, the thickness of the mixed layer is measured and defined as Bt in the portion where a three-layer structure of resin substrate, mixed layer, and cured film layer is observed.

[0019] The lower limit of the cured film thickness At is not particularly limited, but from the viewpoint of good scratch resistance, adhesion, and impact resistance of the resin laminate, it is preferably 12 μm or more, more preferably 14 μm or more, and even more preferably 16 μm or more. The upper limit of the cured film thickness At is not particularly limited, but from the viewpoint of maintaining good heat moldability of the resin laminate, it is preferably 40 μm or less, more preferably 38 μm or less, and even more preferably 36 μm or less. The above preferred upper and lower limits can be combined arbitrarily.

[0020] While there are no particular limitations on the lower limit of Bt / At, it is preferably 0.002 or higher, more preferably 0.01 or higher, and even more preferably 0.02 or higher, from the viewpoint of good impact resistance of the resin laminate and adhesion between the resin substrate and the cured film. On the other hand, while there are no particular limitations on the upper limit of Bt / At, it is preferably 0.3 or lower, more preferably 0.2 or lower, and even more preferably 0.1 or lower, from the viewpoint of maintaining good scratch resistance and heat moldability of the resin laminate. The above preferred upper and lower limits can be combined in any way.

[0021] The term "thickness of the cured film" as used herein refers to the thickness of the cured film in the resin laminate, and can be measured by the measurement method described in the examples below. The value of the film thickness At can be controlled by the cured film formation method and the viscosity of the curable composition, as described later, but is not particularly limited. The value of Bt / At can be controlled by the composition of the curable composition and the integrated amount of active energy rays, but is not particularly limited.

[0022] The adhesion between the resin substrate and the cured film can be evaluated by measuring the remaining percentage of the cured film, as described later.

[0023] The thickness of the resin laminate is not particularly limited, but it can be between 0.2 mm and 15 mm, and preferably between 0.3 mm and 10 mm.

[0024] (mixed layer) The resin laminate of the present invention further comprises a mixed layer between the cured film and the resin substrate, formed by mixing the components of the cured film and the resin substrate forming composition. In some embodiments, the mixed layer may be a layer in which the concentration of the resin substrate forming composition increases continuously from the cured film side to the resin substrate side. The continuous increase in concentration can be confirmed by measuring the change in refractive index on the cross-section of the resin laminate. More specifically, the change in refractive index can be measured by measuring the reflection spectrum using an instantaneous multi-photometer (product of Otsuka Electronics Co., Ltd., product name "MCPD3700").

[0025] The resin laminate of the present invention further comprises such a mixed layer, thereby improving the adhesion between the cured film and the resin substrate. The resin laminate exhibits excellent scratch resistance, adhesion, heat moldability, and impact resistance. The thickness Bt of the mixed layer is preferably 0.1 μm or more and 3.0 μm or less. The thickness Bt of the mixed layer can be measured by Method 1 described below.

[0026] The lower limit of the film thickness Bt is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.5 μm or more, from the viewpoint of good crack resistance of the resin laminate and good adhesion between the cured film and the resin substrate. The upper limit of the film thickness Bt is preferably 3.0 μm or less, more preferably 2.5 μm or less, and even more preferably 2.0 μm or less, from the viewpoint of good hardness and scratch resistance of the resin laminate. The above preferred upper and lower limits can be combined arbitrarily.

[0027] The method for forming the mixed layer is not particularly limited, but for example, the method described below can be used. The curable composition described later is irradiated with active energy rays in an oxygen-containing atmosphere (including air) to cure it to the extent that a mixed layer can be formed by mixing it with the resin substrate forming composition, thereby forming a cured film. After the formation of the cured film, the resin substrate forming composition is applied to the surface on which the cured film has been formed to form the resin substrate. Further details will be explained in the section on the method for manufacturing the resin laminate. The value of the film thickness Bt of the mixed layer can be controlled by the composition of the curable composition, the integrated amount of active energy rays, the polymerization rate, etc., using the resin laminate manufacturing method described later.

[0028] (hardened film) In the resin laminate of the present invention, the cured film contains structural units derived from an isocyanurate skeleton represented by the following formula (1) (hereinafter referred to as "structural units derived from an isocyanurate skeleton").

[0029] [ka]

[0030] In formula (1), R 1 Each of these is independently a divalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents, and the three asterisks indicate the bond position.

[0031] In the structural unit derived from the isocyanuric skeleton, at least one of the three linking groups marked with an asterisk (*) is bonded to the isocyanuric skeleton and to the hydroxyl group of a compound having a hydroxyl group and a (meth)acryloyloxy group in its molecule, as described later, via the linking group "*". When a structural unit derived from an isocyanuric skeleton is bonded to a compound having a hydroxyl group and a (meth)acryloyloxy group in the molecule by one or two linking groups "*", hydrogen atoms may be bonded to the remaining linking groups (linking sites), and other substituents may be bonded as long as they do not hinder the effects of the present invention.

[0032] The inclusion of isocyanurate-derived structural units in the cured film improves the rigidity of the mechanical strength, resulting in superior scratch resistance and impact resistance of the resin laminate.

[0033] The structural units derived from the isocyanurate skeleton contain amide bonds (-NHCO-), which facilitates the formation of a mixed layer between the cured film and the resin substrate, where the components of the cured film and the resin substrate forming composition described later are mixed together. As a result, the resin laminate exhibits excellent scratch resistance, adhesion, and impact resistance.

[0034] Structural unit (A-1): In a suitable resin laminate, the structural unit derived from the isocyanur skeleton is not particularly limited, but the structural unit (A-1) described below can be used. In a resin laminate, the cured film may contain structural units (A-1) derived from a urethane compound having (meth)acryloyloxy groups. The urethane compound having (meth)acryloyloxy groups is a reaction product of a compound (A'-1) having three isocyanate groups in its molecule and a compound (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in its molecule, and the compound (A'-1) having three isocyanate groups in its molecule is represented by the following formula (2).

[0035] [ka]

[0036] In formula (2), R 1 Each of these is independently a divalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents. 1 When the number of carbon atoms is 12 or less, the scratch resistance of the cured coating is improved.

[0037] A suitable cured film in a resin laminate may contain structural units (A-1) derived from a urethane compound having a (meth)acryloyloxy group, which is a reaction product of a compound (A'-1) represented by formula (2) having three isocyanate groups in its molecule and a compound (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in its molecule.

[0038] Examples of structural units (A-1) include those derived from urethane (meth)acrylate obtained by reacting 3 moles or more of compound (a'-1) with 1 mole of compound (A'-1).

[0039] When the cured film has structural units (A-1), a mixed layer is more easily formed between the cured film and the resin substrate by mixing the components of the cured film with the resin substrate forming composition described later. As a result, the resin laminate exhibits excellent scratch resistance, adhesion, and impact resistance.

[0040] Structural unit (A-1) shall not include structural unit (A-2) and structural unit (A-3) described below.

[0041] The compound (A'-1) represented by formula (2) is preferably a trimer of a compound having two isocyanate groups in its molecule. Examples of compounds having two isocyanate groups in their molecule include tolylene diisocyanate, xylylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, norbornene diisocyanate, toluene diisocyanate, trimethylolpropane toluene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and trimethylhexamethylene diisocyanate. Other examples include diisocyanate compounds obtained by hydrogenating aromatic isocyanates among these diisocyanate compounds (e.g., hydrogenated xylylene diisocyanate). By trimerizing these, the compound (A'-1) represented by formula (2) can be obtained.

[0042] Compound (a'-1), which has a hydroxyl group and a (meth)acryloyloxy group in its molecule, can be reacted with compound (A'-1) represented by formula (2) to obtain a urethane compound having a (meth)acryloyloxy group. Examples of compounds (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in the molecule include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-methoxypropyl (meth)acrylate, 1,2,3-propanetriol-1,3-dimethacrylate, 3-acryloyloxy-2-hydroxypropyl meth)acrylate, N-methylol (meth)acrylamide, and N-hydroxy(meth)acrylamide.

[0043] Compound (a'-1) may have multiple acryloyloxy groups or methacryloyloxy groups. A urethane compound can be obtained in which a structural unit (A-1) having a (meth)acryloyloxy group is formed by the reaction of the hydroxyl group of compound (a'-1) with the isocyanate group of compound (A-1) represented by formula (2).

[0044] In particular, structural unit (A-1) derived from a urethane compound obtained by the reaction of a trimer of hexamethylene diisocyanate with 1,2,3-propanetriol-1,3-dimethacrylate or 3-acryloyloxy-2-hydroxypropyl(meth)acrylate is preferred in terms of the balance of scratch resistance, adhesion, heat-formability, and impact resistance of the resin laminate.

[0045] Structural unit (A-2): In a suitable resin laminate, the cured film may further contain structural units (A-2) derived from a polymerizable compound having three or four (meth)acryloyloxy groups in its molecule. However, structural units (A-2) shall not contain the aforementioned structural units (A-1). When the cured film contains structural units (A-2), the resin laminate exhibits excellent scratch resistance.

[0046] Structural units (A-2) may include, but are not limited to, structural units derived from the following compound (C-1) or structural units derived from the following compound (C-2).

[0047] Compound (C-1) is an ester compound obtained from 1 mole of a polyhydric alcohol and 3 moles or more of (meth)acrylic acid or its derivatives. Examples of compound (C-1) include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, ethylene oxide adduct trimethylolpropane tri(meth)acrylate, propylene oxide adduct trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentagriserol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate. Examples include tra(meth)acrylate, glycerin tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, ethylene oxide adduct pentaerythritol tetra(meth)acrylate, caprolactone adduct dipentaerythritol penta(meth)acrylate, and caprolactone adduct dipentaerythritol hexa(meth)acrylate.

[0048] Compound (C-2) is a linear ester compound obtained from a polyhydric alcohol, a polyhydric carboxylic acid or its anhydride, and (meth)acrylic acid or its derivative. Preferred combinations of polyhydric carboxylic acid or its anhydride / polyhydric alcohol / (meth)acrylic acid are exemplified below, but are not particularly limited. Malonic acid / trimethylolethane / (meth)acrylic acid, Malonic acid / trimethylolpropane / (meth)acrylic acid, Malonic acid / glycerin / (meth)acrylic acid, Malonic acid / Pentaerythritol / (meth)acrylic acid, Succinic acid / trimethylolethane / (meth)acrylic acid, Adipic acid / trimethylolethane / (meth)acrylic acid, Glutaric acid / trimethylolethane / (meth)acrylic acid, Sebacic acid / trimethylolethane / (meth)acrylic acid, Fumaric acid / trimethylolethane / (meth)acrylic acid, Itaconic acid / trimethylolethane / (meth)acrylic acid, Maleic anhydride / trimethylolethane / (meth)acrylic acid, etc.

[0049] Polyhydric alcohols, polyhydric carboxylic acids or their anhydrides, and (meth)acrylic acid may be used individually or in combination of two or more.

[0050] Here, "polyhydric alcohol" refers to an alcohol having two or more hydroxyl groups in its molecule. "Polyhydric carboxylic acid" refers to a carboxylic acid having two or more carboxyl groups in its molecule. "(meth)acrylic acid derivative" refers to a compound in which a functional group or hydrogen atom of a (meth)acrylic acid compound is substituted with another functional group. "Polyhydric carboxylic acid derivative" refers to a compound in which a functional group or hydrogen atom of a polyhydric carboxylic acid is substituted with another functional group. "Linear" refers to both linear and branched chains.

[0051] The structural unit (A-2) is preferably a structural unit derived from compound (C-1), and preferably at least one selected from the structural units derived from pentaerythritol tri(meth)acrylate and the structural units derived from pentaerythritol tetra(meth)acrylate.

[0052] Structural unit (A-3): In a suitable resin laminate, the cured film may further contain structural unit (A-3) derived from a polymerizable compound having two (meth)acryloyloxy groups in its molecule. However, structural unit (A-3) shall not contain the aforementioned structural unit (A-1). When the cured film contains structural unit (A-3), the viscosity of the curable composition, which is the raw material for the cured film, can be lowered. As a result, a mixed layer is more easily formed between the cured film and the resin substrate, which is a mixture of the components of the cured film and the resin substrate forming composition described later. Consequently, the resin laminate exhibits excellent scratch resistance, adhesion, and impact resistance. Furthermore, since the rigidity of the cured film itself is prevented from becoming excessively high, the resin molded article exhibits excellent impact resistance.

[0053] Structural unit (A-3) is derived from a polymerizable compound having two (meth)acryloyloxy groups in the molecule. Examples of polymerizable compounds having two (meth)acryloyloxy groups in the molecule include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dicyclopentenyl di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, ethylene oxide adduct trimethylolpropane di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di( Examples include meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyester di(meth)acrylate, polyethylene glycol di(meth)acrylate, tricyclodecanedimethylol di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. Polymerizable compounds having two (meth)acryloyloxy groups in their molecule may be used individually or in combination of two or more.

[0054] As a polymerizable compound having two (meth)acryloyloxy groups in the molecule, 1,6-hexanediol di(meth)acrylate is preferred. Therefore, structural unit (A-3) derived from 1,6-hexanediol di(meth)acrylate is preferred.

[0055] Another example of a structural unit (A-3) is a structural unit derived from a compound obtained from an esterified product having two (meth)acryloyloxy groups in one molecule. An esterified product having two (meth)acryloyloxy groups in one molecule can be obtained from a polyhydric alcohol, a polyhydric carboxylic acid or its anhydride, and (meth)acrylic acid or its derivative. Examples of polycarboxylic acids or their anhydrides include malonic acid, succinic acid, adipic acid, glutaric acid, sebacic acid, fumaric acid, itaconic acid, and maleic anhydride. Examples of polyhydric alcohols include trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol.

[0056] The terms "polyhydric alcohol," "polyhydric carboxylic acid," and "(meth)acrylic acid derivatives" used here are the same as those explained in structural unit (A-2). The various compounds mentioned above may be used individually or in combination of two or more.

[0057] Regarding preferred combinations of structural units (A-1), (A-2), and (A-3), a preferred combination is one in which structural unit (A-1) is derived from a urethane compound having a (meth)acryloyloxy group, which is a reaction product of a compound (A'-1) represented by formula (2) and a compound (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in its molecule; structural unit (A-2) is derived from at least one monomer or monomer mixture selected from pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; and structural unit (A-3) is derived from 1,6-hexanediol di(meth)acrylate, but is not particularly limited.

[0058] The cured film may further contain structural units (A-4) derived from other polymerizable compounds that do not fall under any of structural units (A-1), (A-2), or (A-3), as long as they do not impair the performance of the resin laminate.

[0059] The lower limit of the content of structural unit (A-1) in the cured film is not particularly limited, but from the viewpoint of good scratch resistance, adhesion, and impact resistance of the resin laminate, it is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 22% by mass or more, based on 100% of the total mass of the cured film. The upper limit of the content of structural unit (A-1) is not particularly limited, but to prevent the scratch resistance of the cured film itself from becoming excessively low and to maintain good scratch resistance of the resin laminate, it is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 33% by mass or less. The above preferred upper and lower limits can be combined arbitrarily. The content of structural unit (A-1) in the cured film is preferably 10 to 40% by mass of the total mass of the cured film, more preferably 20 to 35% by mass, and even more preferably 22 to 33% by mass.

[0060] The lower limit of the content ratio of structural units (A-2) in the cured film is not particularly limited, but from the viewpoint of good scratch resistance of the resin laminate, it is preferably 5% by mass or more, and more preferably 15% by mass or more, based on 100% of the total mass of the cured film. The upper limit of the content ratio of structural units (A-2) is not particularly limited, but from the viewpoint of preventing the rigidity of the cured film itself from becoming excessively high and maintaining good impact resistance of the resin layer, it is preferably 35% by mass or less, and more preferably 25% by mass or less. The above preferred upper and lower limits can be combined arbitrarily. The content of structural unit (A-2) in the cured film is preferably 5 to 35% by mass of the total mass of the cured film, and more preferably 15 to 25% by mass.

[0061] While there is no particular lower limit to the content ratio of structural unit (A-3) in the cured film, from the viewpoint of achieving good scratch resistance, adhesion, and impact resistance of the resin laminate and good viscosity of the curing liquid composition, it is preferable that the content ratio be 40% by mass or more, and more preferably 45% by mass or more, based on 100% of the total mass of the cured film. While there is no particular upper limit to the content ratio of structural unit (A-3), it is preferable that the content ratio be 65% by mass or less, and more preferably 62% by mass or less, in order to maintain good scratch resistance and impact resistance of the resin laminate. The above preferred upper and lower limits can be combined arbitrarily. The content of structural unit (A-3) in the cured film is preferably 40 to 65% by mass of the total mass of the cured film, and more preferably 45 to 62% by mass.

[0062] The preferred upper and lower limits of structural unit (A-1), structural unit (A-2), and structural unit (A-3) can be arbitrarily combined. In some suitable resin laminates, the content of structural unit (A-1) may be 10% to 40% by mass of the total mass of the cured film, the content of structural unit (A-2) may be 5% to 35% by mass of the total mass of the cured film, and the content of structural unit (A-3) may be 40% to 65% by mass of the total mass of the cured film. In some suitable resin laminates, the content of structural unit (A-1) may be 20% to 35% by mass of the total mass of the cured film, the content of structural unit (A-2) may be 15% to 25% by mass of the total mass of the cured film, and the content of structural unit (A-3) may be 45% to 62% by mass of the total mass of the cured film. In some suitable resin laminates, the content of structural unit (A-1) may be 22% to 33% by mass of the total mass of the cured film, the content of structural unit (A-2) may be 15% to 25% by mass of the total mass of the cured film, and the content of structural unit (A-3) may be 45% to 62% by mass of the total mass of the cured film.

[0063] A cured film of a resin laminate can be formed, for example, by applying and curing a curable composition. The curable composition contains a urethane compound having (meth)acryloyloxy groups to form structural unit (A-1), a polymerizable compound having 3 or 4 (meth)acryloyloxy groups in the molecule to form structural unit (A-2), and a polymerizable compound having 2 (meth)acryloyloxy groups in the molecule to form structural unit (A-3). The urethane compound having (meth)acryloyloxy groups is a reaction product of the above-mentioned compound (A-1) and compound (a'-1). The preferred proportions and details of each compound to be incorporated into the curable composition are as previously described.

[0064] The cured film and the curable composition for forming it may further contain various additives as needed, such as mold release agents, lubricants, plasticizers, antioxidants, antistatic agents, light stabilizers, ultraviolet absorbers, flame retardants, flame retardant aids, polymerization inhibitors, fillers, pigments, dyes, silane coupling agents, leveling agents, defoamers, fluorescent agents, and chain transfer agents.

[0065] (Resin base material) As the resin substrate in the resin laminate of the present invention, a (meth)acrylic resin having structural units derived from methyl methacrylate and structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule is preferred, from the viewpoint of excellent transparency, impact resistance, and heat resistance of the resin laminate.

[0066] Examples of polymerizable compounds (B-1) having two or more (meth)acryloyl groups in a single molecule can be appropriately selected from the compounds exemplified in the descriptions of structural units (A-1), (A-2), and (A-3) above. From the viewpoint of transparency of the resin substrate, at least one polymerizable compound (B-1) having two or more (meth)acryloyl groups in a single molecule is preferably selected from neopentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

[0067] "A (meth)acrylic resin having structural units derived from methyl methacrylate and structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule" is a copolymer containing 60% by mass or more of structural units derived from methyl methacrylate and 0.5% by mass or more and 40% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, based on 100% of the total mass of all structural units constituting the (meth)acrylic resin. The (meth)acrylic resin may also contain structural units derived from other monomers as long as the above content ratios are met.

[0068] Other monomers copolymerizable with methyl methacrylate and polymerizable compounds (B-1) having two or more (meth)acryloyl groups in a single molecule can be appropriately selected from the compounds exemplified in the descriptions of structural units (A-1), (A-2), and (A-3) above. Other examples of monomers include the following:

[0069] Methacrylic acid ester Examples include, but are not limited to, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, and benzyl methacrylate.

[0070] Acrylate ester Examples include, but are not limited to, methyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, and 2-ethylhexyl acrylate.

[0071] unsaturated carboxylic acid Examples include, but are not limited to, acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

[0072] Unsaturated carboxylic acid anhydride Examples include maleic anhydride and itaconic anhydride, but are not limited to these.

[0073] Maleimide Examples include, but are not limited to, N-phenylmaleimide and N-cyclohexylmaleimide.

[0074] hydroxyl group-containing vinyl monomer Examples include, but are not limited to, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate.

[0075] Vinyl ester Examples include vinyl acetate and vinyl benzoate, but are not limited to these.

[0076] Halogen-containing vinyl monomers Examples include, but are not limited to, vinyl chloride, vinylidene chloride, and their derivatives.

[0077] Nitrogen-containing vinyl monomers Examples include, but are not limited to, methacrylamide and acrylonitrile.

[0078] epoxy group-containing monomer Examples include glycidyl acrylate and glycidyl methacrylate, but are not limited to these.

[0079] Aromatic vinyl monomer Examples include styrene and α-methylstyrene, but are not limited to these.

[0080] Other monomers may be used individually or in combination of two or more. From the viewpoint of providing an excellent balance of transparency, heat resistance, and impact resistance of the resin laminate, methyl acrylate, ethyl acrylate, and n-butyl acrylate are preferred.

[0081] Furthermore, the following monomers are also given as examples. Vinyl monomers having two or more ethylenically unsaturated bonds in their molecules, such as divinylbenzene. Unsaturated polyester prepolymer obtained from at least one polycarboxylic acid containing an ethylenically unsaturated polycarboxylic acid and at least one diol. Vinyl ester prepolymer obtained by modifying the ends of epoxy groups with acrylic. These may be used individually or in combination of two or more types.

[0082] (Meth)acrylic resins having structural units derived from methyl methacrylate and structural units derived from polymerizable compound (B-1) having two or more (meth)acryloyl groups in a single molecule can be obtained, for example, by polymerizing a composition of radical polymerizable monomers. The radical polymerizable monomer composition may be a resin substrate forming composition containing a mixture of radical polymerizable monomers, comprising 60% to 99.5% by mass of methyl methacrylate, 0.5% to 40% by mass of a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, 0 to 39.5% by mass of other monomers copolymerizable with methyl methacrylate and the polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, and the total amount of methyl methacrylate, the polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, and the monomer copolymerizable with methyl methacrylate not exceeding 100% by mass.

[0083] The lower limit of the content of structural units derived from methyl methacrylate is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, in terms of ensuring the transparency and adhesion of the substrate. The upper limit of the content of structural units derived from methyl methacrylate is preferably 99.5% by mass or less, more preferably 99% by mass or less, and even more preferably 98% by mass or less, in terms of ensuring the warp resistance, heat resistance, and adhesion of the substrate.

[0084] The lower limit of the content of structural units derived from polymerizable compound (B-1) having two or more (meth)acryloyl groups in a single molecule is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, in order to ensure the warp resistance, heat resistance, and adhesion of the substrate. Warping is thought to occur when non-uniform strain remaining inside the resin during polymerization becomes apparent due to the softening of the resin by heating. If the lower limit of the content of structural units derived from polymerizable compound (B-1) having two or more (meth)acryloyl groups in a single molecule is at the concentration shown above, heat resistance is improved, and strain due to heat from the equipment and the operating environment is less likely to become apparent. As a result, warping is thought to be reduced.

[0085] The upper limit of the content of structural units derived from polymerizable compounds (B-1) having two or more (meth)acryloyl groups in a single molecule is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, in terms of ensuring the transparency, adhesion, and impact resistance of the substrate.

[0086] (Composition for forming resin base material) The raw materials for resin substrates are called resin substrate forming compositions. A resin substrate forming composition is a mixture containing radical polymerizable monomers, in which the total mass of the (meth)acrylic resin is 60% to 99.5% by mass of methyl methacrylate, 0.5% to 40% by mass of polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, and the total amount of monomers copolymerizable with methyl methacrylate and polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule does not exceed 100% by mass.

[0087] As a composition for forming a resin substrate, a syrup can also be used which is a mixture of a partially polymerized polymer obtained by polymerizing a portion of the mixture containing the above-mentioned radical polymerizable monomers and the remaining radical polymerizable monomers. If necessary, as a composition for forming a resin substrate, a type of syrup can also be used which is obtained by dissolving a (meth)acrylic polymer as a raw material for the resin substrate in the above-mentioned mixture of radical polymerizable monomers mainly composed of methyl methacrylate.

[0088] The mass-average molecular weight of the partial polymer in the syrup or the (meth)acrylic polymer as the resin substrate forming composition is not particularly limited and can be between 50,000 and 300,000. Furthermore, the mixing ratio of the partial polymer or (meth)acrylic resin in the syrup to the radical polymerizable monomer can be between 2:98 and 50:50 by mass.

[0089] An initiator may be added to the composition for forming the resin substrate. Examples of initiators include organic oxides and azo compounds. The amount of initiator to be added is not particularly limited, but it is preferably 0.005 to 8% by mass relative to 100% by mass of the radical polymerizable monomer in the composition for forming the resin substrate.

[0090] The resin substrate forming composition may further contain, as needed, various additives such as mold release agents, lubricants, plasticizers, antioxidants, antistatic agents, light stabilizers, ultraviolet absorbers, flame retardants, flame retardant aids, polymerization inhibitors, fillers, pigments, dyes, silane coupling agents, leveling agents, defoamers, fluorescent agents, or chain transfer agents.

[0091] Methods for polymerizing a composition for forming a resin substrate to obtain a resin substrate include, for example, bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. From the viewpoint of transparency of the resin laminate, environmental burden due to solvent use, productivity of the resin laminate, and manufacturing cost, bulk polymerization is preferred. The specific means of bulk polymerization are not particularly limited, but for example, the casting polymerization method described later can be used.

[0092] (Method for manufacturing resin laminates) The method for manufacturing the resin laminate is not particularly limited, but for example, it can be manufactured by each of the following steps (1) to (4).

[0093] Step (1): After applying the curable composition, which is the raw material for the cured film, to the surface of the mold, the curable composition exposed to an oxygen-containing atmosphere is irradiated with active energy rays to cure it and form a cured film, thereby forming a laminated mold on the surface of the mold with the cured film layered on top. Step (2): Next, a resin substrate forming composition containing a mixture of methyl methacrylate, which is a raw material for the resin substrate, and a radical polymerizable monomer containing a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule, is injected into the laminated mold or applied to the surface of the laminated mold on which the cured film has been formed. Step (3): Next, the resin substrate forming composition is cured by heating polymerization to obtain a laminate in which the resin substrate is formed on the surface of the cured film. Step (4): Next, the laminate obtained in step (3) is peeled off the mold to obtain a resin laminate in which a cured film is laminated on the surface of a resin substrate.

[0094] A suitable method for manufacturing a resin laminate is: Applying a curable composition to the surface of the mold, The curable composition exposed to an oxygen-containing atmosphere is irradiated with active energy rays to cure it to the extent that it can form a layer in which it is mixed with the resin substrate forming composition to be applied later, thereby obtaining a laminated mold on which a cured film is provided on the surface of the mold. The resin substrate forming composition is injected into the laminated mold, and after forming a layer in which the components of the cured film and the resin substrate forming composition are mixed with each other, the resin substrate forming composition is cured by casting polymerization to form a laminate in which the resin substrate is formed on the surface of the cured film, and The mold is peeled off to obtain a resin laminate in which a cured film is laminated on the surface of the resin substrate. It can also be described as a method for manufacturing resin laminates, including [the specified element].

[0095] Methods for applying a curable composition to the surface of a mold include, for example, brush coating, casting, roller coating, bar coating, spray coating, air knife coating, and dipping. One method for curing a curable composition by irradiating it with active energy rays is to incorporate a photopolymerization initiator and then irradiate it with active energy rays.

[0096] Examples of photopolymerization initiators include carbonyl compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α,α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4'-bis(dimethylamino)benzophenone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. Sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide, Examples include, but are not limited to, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and benzoyldiethoxyphosphine oxide. One photopolymerization initiator may be used alone, or two or more may be used in combination. The amount of photopolymerization initiator used is usually 0.1 to 10 parts by mass per 100 parts by mass of the curable composition, but is not particularly limited.

[0097] Examples of active energy rays include electron beams, ultraviolet light, and visible light, but ultraviolet light is preferred from the viewpoint of superior equipment cost and productivity. There is no particular lower limit to the integrated light intensity of the active energy rays, but 200 mJ / cm² is preferable. 2 A value of 400 mJ / cm² is preferable from the viewpoint of good scratch resistance and surface hardness. 2 The above is preferable. There is no particular upper limit to the integrated light intensity of the active energy rays, but 1500 mJ / cm² is preferable. 2The following is preferable, as it results in a mixed layer formed between the cured film and the resin substrate by mixing the components of the cured film and the composition for forming the resin substrate: 1200 mJ / cm² 2 The following are preferable.

[0098] In the curing process, by irradiating a curable composition exposed to an oxygen-containing atmosphere with active energy rays, a mixed layer can be formed between the cured film and the resin substrate, for reasons described later, in which the components of the cured film and the composition for forming the resin substrate are mixed together.

[0099] Examples of light sources for active energy rays include fluorescent ultraviolet lamps, ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low pressure mercury lamps, metal halide lamps, Ar lasers, He-Cd lasers, solid-state lasers, xenon lamps, high-frequency induction mercury lamps, and sunlight. Among these, fluorescent ultraviolet lamps and high pressure mercury lamps are preferred in terms of the curing speed of the curable composition.

[0100] Examples of photopolymerization initiators used in photocuring include carbonyl compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α,α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4'-bis(dimethylamino)benzophenone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; and 2,4,6-trimethylbenzoyldiphenylphosphine oxide and benzoyldiethoxyphosphine oxide. The amount of photopolymerization initiator added is usually 0.1 parts by mass to 10 parts by mass per 100 parts by mass of the curable composition, but is not particularly limited.

[0101] Furthermore, in the curing process of step (1), the curable composition can be irradiated with active energy rays while exposed to an oxygen-containing atmosphere. Irradiating the curable composition with active energy rays in an oxygen-containing atmosphere makes it more susceptible to oxygen-induced curing inhibition during the curing reaction, allowing the curable composition to be cured to a degree that it can form a layer in which it is mixed with the resin substrate forming composition that is applied later. When the resin substrate forming composition is injected or applied to the surface on which the cured film has been formed, a layer is formed in which the components of the cured film and the resin substrate forming composition are mixed with each other. By curing this layer, a mixed layer is formed between the cured film and the resin substrate in the final resin laminate, in which the components of the cured film and the resin substrate forming composition are mixed with each other. As a result, the crack resistance and adhesion of the resin laminate are expected to improve. Here, "oxygen-containing atmosphere" does not have any particular restrictions as long as it is in the presence of an oxygen-containing gas, but considering economy and ease of use, air is particularly excellent.

[0102] Examples of mold types include metal molds and sheet molds. Regarding molds, typically two molds are used so that the surfaces on which the hardened coating is laminated face each other. It is preferable that the surfaces on which the hardened coating is laminated in the mold have smooth surfaces.

[0103] Examples of mold materials include stainless steel, glass, and resin. The mold may consist of two molds made of the same material facing each other, or two molds made of different materials facing each other.

[0104] The method for producing the mold is not particularly limited, but for example, one method involves first arranging one laminated mold (1) on which a hardened film is formed on the surface of one mold, then arranging another mold (2) opposite to the laminated mold, and then providing a gasket made of soft resin to seal the periphery of the space formed between the laminated mold (1) and the mold (2) to produce a laminated mold having a certain internal volume.

[0105] The cured film may be formed on the surface of one mold, or on the inner surfaces of two molds positioned opposite each other.

[0106] A resin substrate-forming composition is injected into the resulting laminated mold and cast polymerization is performed to form a resin substrate. Subsequently, a resin laminate can be obtained by removing the resin substrate from the mold with the cured film and the resin substrate integrated together.

[0107] "Casting polymerization" refers to a method of polymerization in which a resin substrate-forming composition is injected into a laminated mold, for example, using a mold formed by two molds facing each other at a predetermined distance apart and a sealing material placed around its periphery.

[0108] One example of a casting polymerization method for resin substrate formation compositions is the cell casting method, in which the resin substrate formation composition is injected into a laminated mold and then heated. In addition to the methods described above, continuous casting polymerization is also a suitable method for casting polymerization of compositions for forming resin substrates.

[0109] Continuous casting polymerization is a polymerization method in which a resin substrate forming composition is continuously injected from upstream into a space formed by sealing both ends of two opposing stainless steel endless belts, each having a hardened coating on its surface, with another stainless steel endless belt, and heating the space. This space is then heated.

[0110] One method for heating the laminated mold is to heat the mold with a heat source such as hot water at 30 to 98°C. The polymerization time is determined appropriately according to the progress of polymerization.

[0111] In order to increase the polymerization rate of the composition for forming the resin substrate, heat treatment at 90 to 150 °C can also be performed as necessary using a heat source such as a far-infrared heater. The polymerization time is appropriately determined according to the progress of the polymerization. After the heat treatment, a cooling treatment such as blowing can be performed as necessary.

[0112] The present embodiment described above includes at least the following [1] to

[10] , but is not limited thereto. [1] A sheet-like resin laminate having a cured film on at least one surface of a resin substrate, The resin laminate further includes a mixed layer between the cured film and the resin substrate, The mixed layer is formed by mixing the components of the cured film and the composition for forming the resin substrate that forms the resin substrate, The cured film contains a structural unit derived from an isocyanuric skeleton represented by the following formula (1), The resin substrate contains 60% by mass or more of a structural unit derived from methyl methacrylate and 0.5% by mass or more and 40% by mass or less of a structural unit derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule. Resin laminate.

[0113] [Chemical formula]

[0114] In formula (1), R 1 Each independently represents a divalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and the three * each indicate a bonding position.

[0115] [2] The resin laminate according to [l], wherein the film thickness Bt of the mixed layer is 3.0 μm or less. [3] The resin laminate according to [1] or [2], wherein the film thickness Bt of the mixed layer is 0.1 μm or more and 3.0 μm or less. [4] The resin laminate according to any one of [1] to [3], wherein the cured film contains a structural unit (A-1) derived from a urethane compound having a (meth)acryloyloxy group, which is a reaction product of a compound (A'-1) represented by the following formula (2) having three isocyanate groups in its molecule and a compound (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in its molecule.

[0116] [ka]

[0117] In formula (2), R 1 Each of these is independently a divalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents.

[0118] [5] The resin laminate according to [4], wherein the cured film further contains a structural unit (A-2) derived from a polymerizable compound having three or four (meth)acryloyloxy groups in its molecule, and a structural unit (A-3) derived from a polymerizable compound having two (meth)acryloyloxy groups in its molecule. [6] The content ratio of the structural unit (A-1) is 10% by mass or more and 40% by mass or less of the total mass of the cured film, The content ratio of the structural unit (A-2) is 5% by mass or more and 35% by mass or less of the total mass of the cured film. The resin laminate according to [4] or [5], wherein the content of the structural unit (A-3) is 40% by mass or more and 65% by mass or less of the total mass of the cured film. [7] The resin laminate according to any one of [1] to [6], wherein the resin substrate contains 80% by mass or more of structural units derived from methyl methacrylate, and contains 1% by mass or more and 20% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule. [8] The resin laminate according to any one of [1] to [7], wherein the resin substrate contains 90% by mass or more of structural units derived from methyl methacrylate, and contains 2% by mass or more and 10% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule. [9] A resin laminate according to any of [1] to [8] that satisfies both of the following conditions A and B. Condition A: 12 μm ≤ At ≤ 40 μm Condition B: 0.002≦(Bt / At)≦0.3 However, At is the thickness of the cured film, and Bt is the thickness of the mixed layer (μm) measured by the method 1 below. Method 1: The resin laminate is cut perpendicular to the main surface, and then a small piece for transmission electron microscopy is cut from the cut surface using a microtome. An observation image of the cross-section of the cut piece is obtained using a transmission electron microscope. In the obtained observation image, the thickness of the mixed layer is measured and defined as Bt in the portion where a three-layer structure of resin substrate, mixed layer, and cured film layer is observed.

[10] The resin laminate according to any one of [1] to [9], wherein the mixed layer is a layer in which the concentration of the resin substrate forming composition increases continuously from the cured film side to the resin substrate side. [Examples]

[0119] The embodiments will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0120] [Measurement, evaluation] The detailed methods for measurement and evaluation are as follows:

[0121] (Film thickness of cured coating: At) The cured film thickness (At) is the average value of three arbitrary measurements taken at different points on a cross-section of the resin laminate, perpendicular to the main surface, taken using a differential interference microscope. The measurement is taken from the surface of the cured film in contact with the mixed layer to the surface of the cured film on the resin laminate. If the mixed layer is not observed, the measurement from the surface of the cured film in contact with the resin substrate to the surface of the cured film on the resin laminate is used.

[0122] (Film thickness of the mixed layer: Bt) The resin laminate was cut perpendicular to its main surface. Next, a small piece for transmission electron microscopy was cut from the cut surface of the resin laminate using a microtome. A TEM image was obtained by observing the cross-section of the small piece using a transmission electron microscope (TEM: JEOL Ltd. product, model: JEM-10111, acceleration voltage 100V, magnification 10000x). For the portion of the obtained TEM image where a three-layer structure of resin substrate layer / mixed layer / cured film layer was observed, the film thickness of the cured film layer and the mixed layer was measured, and the film thickness of the mixed layer was defined as Bt. An example of a TEM image showing a three-layer structure is shown in Figure 3. In Figure 3, a three-layer structure of resin substrate layer 4 / mixed layer 5 / cured film layer 6 was observed.

[0123] (transparency) The haze value (%) of the resin laminate was measured using a haze meter (product of Nippon Denshoku Industries Co., Ltd., product name: HAZEMETER ND4000) in accordance with the measurement method specified in JIS K7136:2000.

[0124] (Scratch resistance) The scratch resistance of the cured film surface in resin laminates was evaluated by the difference in haze value (△haze (%)) before and after the scratch test. The abrasion test and evaluation of abrasion resistance were conducted as follows. First, a 24mm diameter circular pad fitted with #000 steel wool (Bonstar No. 000, a product of Nippon Steel Wool Co., Ltd.) was placed on the surface of the cured coating side of the resin laminate. It was moved back and forth 100 times over a distance of 50mm under a load of 2,000g. Then, the difference between the haze value before abrasion and the haze value after abrasion (△haze (%)) was calculated using the following formula. [△Haze (%)] = [Haze value after abrasion test (%)] - [Haze value before abrasion test (%)]

[0125] (Adhesion) As an indicator of the adhesion between the cured film and the resin substrate in a resin laminate, a cross-cut peel test with 25 squares was conducted at three locations in accordance with JIS K5600-5-6. The retention rate (%) of the cured film that remained on the surface of the resin laminate without peeling was measured within a total of 75 squares.

[0126] (Impact resistance) The impact resistance of the resin laminate was evaluated using a DuPont impact tester (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name) on a resin laminate test specimen (50 mm × 50 mm × 1.5 mm). The radius of the impact point was set to 7.9 mm (5 / 16 inch), and the 50% fracture energy was calculated in accordance with ASTM D2794 using a 300 g weight. Specimens that cracked were considered fractured. Measurements were taken on 10 resin laminate test specimens, and the average value was calculated.

[0127] (Warpage resistance) As an indicator of thermal warping of resin laminates, the warping of a resin laminate test specimen (100 mm × 100 mm × 1.5 mm) after a durability test (100 hours at 80°C) was evaluated. After the durability test was completed, the specimen was cooled to room temperature. After the specimen had cooled to room temperature, it was placed on a glass mirror surface. The amount of warping at each of the four corners of the specimen was measured using a jig and evaluated based on the following criteria. A: The average curvature of the four corners is less than 1 mm. B: The average curvature of the four corners is 1 mm or more but less than 3 mm. C: The average curvature of the four corners is 3 mm or more.

[0128] (Thermal deflection test: HDT) As an indicator of the heat resistance of the resin laminate, a thermal deflection test was conducted in accordance with JIS K7191-1 using an HDT measuring device (Heat Distortion Tester 148-HD-PC3, a product of Yasuda Seiki Seisakusho Co., Ltd.).

[0129] [Abbreviation, material] The materials used in the examples and their abbreviations are shown below. U6HA: A urethane compound obtained by reacting 3 moles of 3-acryloyloxy-2-hydroxypropyl methacrylate with 1 mole of triisocyanate obtained by trimerizing hexamethylene diisocyanate (product of Shin-Nakamura Chemical Industry Co., Ltd.) M305: Mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (product of Toagosei Co., Ltd.) C6DA: 1,6-Hexanediol diacrylate (product of Osaka Organic Chemical Industry Co., Ltd.) NPGDMA: Neopentyl glycol dimethacrylate (product of Shin-Nakamura Chemical Industry Co., Ltd.) EDMA: Ethylene glycol dimethacrylate (product of Kyoeisha Chemical Co., Ltd.) ABN-V: 2,2'-Azobis-(2,4-dimethylvaleronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd.) Darocure 1173: 2-Hydroxy-2-methyl-1-phenylpropan-1-one (BASF Japan Co., Ltd. product) IRGACURE819: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BASF Japan Co., Ltd. product)

[0130] [Example 1] 100 parts of MMA were supplied to a reactor (polymerization vessel) equipped with a condenser, thermometer, and stirrer. After bubbling with nitrogen gas while stirring, heating was started. When the internal temperature reached 60°C, 0.1 parts of ABN-V was added as a radical polymerization initiator, and the internal temperature was further heated to 100°C and held for 13 minutes. After that, the reactor was cooled to room temperature to obtain syrup. The solid content concentration of the syrup was 30% by mass. This syrup and NPGDMA were mixed in a ratio of 99 / 1 (by mass) to obtain resin substrate forming composition (1).

[0131] A curable composition (2) was obtained by mixing 30 parts of U6HA, 20 parts of M305, 50 parts of C6DA, 3.0 parts of Darocure1173, and 0.15 parts of IRGACURE819. Next, using a SUS304 plate with a mirror-finished surface as a mold, the curable composition (2) was coated onto the surface of the mold using a bar coater to create a pre-curing film layer (2-1) with a cured film thickness of 20 μm.

[0132] Next, the mold with the pre-curing coating (2-1) applied is placed so that the layer of the pre-curing coating (2-1) is on top, and a high-pressure mercury lamp (output 30W / cm²) is placed over it. 2 The uncured film (2-1), exposed to air, was irradiated with ultraviolet light from a high-pressure mercury lamp while passing 20 cm below the surface at a speed of 10 m / min. The uncured film (2-1) was cured to form a cured film. A laminated mold (2A) was obtained in which a cured film with a thickness of 20 μm was laminated on the surface of the mold. Separately, a laminated mold (2A') was obtained by performing the same procedure to which a cured film with a thickness of 20 μm was laminated on the surface of the mold. Laminated molds (2A) and (2A') were placed so that the cured films faced each other. The periphery of these two SUS304 plates was sealed with a gasket made of soft resin to create a laminated mold (2B).

[0133] Next, after removing dissolved air under reduced pressure, the resin substrate forming composition (1) was injected into the laminated mold (2B) and completely sealed with a gasket made of soft resin. Then, the laminated mold (2B) was heated in an 80°C water bath for 1 hour, and then in a 130°C air furnace for 1 hour. The resin substrate forming composition (1) was polymerized to form a layer of resin substrate. After the laminated mold (2B) was cooled to room temperature, the two SUS304 plates on both sides were peeled off the laminated mold (2B) to obtain a 1.5 mm thick resin laminate with a cured coating on both sides of the resin substrate layer. The evaluation results of the obtained resin laminate are shown in Table 1.

[0134] [Examples 2-10, Comparative Examples 1-3] A resin laminate was obtained in the same manner as in Example 1, except that the compound compositions of the resin substrate forming composition (1) and the curable composition (2) were changed as shown in Table 1 or Table 2. The evaluation results of the obtained resin laminate are shown in Tables 1 and 2.

[0135] [Comparative Example 4] A syrup was obtained in the same manner as in Example 1. The syrup and NPGDMA were mixed in a ratio of 95 / 5 (mass%) to obtain resin substrate forming composition (1). Next, after removing dissolved air under reduced pressure, the resin substrate forming composition (1) was poured into a laminated mold (2B) and completely sealed with a gasket made of soft resin. Next, the laminated mold (2B) was heated in an 80°C water bath for 1 hour, and then in a 130°C air furnace for 1 hour. The resin substrate forming composition (1) was polymerized to form a layer of resin substrate. After the laminated mold (2B) was cooled to room temperature, the two SUS304 plates on both sides were peeled off the laminated mold (2B) to obtain a resin laminate with a thickness of 1.5 mm. The mixing ratio of curable composition (2) was changed as shown in Table 2 and applied to one side of this resin laminate. Immediately after applying the curable composition (2), a PET film "OX-50" (a product of Teijin DuPont Films Ltd.) was bonded to the methacrylic resin plate so that the highly smooth surface of the film was in contact with the surface coated with the curable composition (2). The plate was pressed with a press roll at a speed of 7 m / min. The film thickness of the curable composition (2) was adjusted so that the final cured film thickness was 20 μm.

[0136] The laminate, consisting of a methacrylic resin plate, a layer of curable composition (2), and a PET film, was held in place for 1 minute. Afterward, a high-pressure mercury lamp (output 30W / cm²) was used. 2 The ultraviolet light from the high-pressure mercury lamp was irradiated onto the curable composition (2) through the PET film while passing it at a speed of 3.0 m / min at a position 20 cm below the PET film. A cured laminate was obtained in which the methacrylic resin plate, cured film, and PET film were sequentially laminated. Thus, in Comparative Example 4, the curable composition (2), which was not exposed to an oxygen-containing atmosphere by the PET film, was irradiated with ultraviolet light from the high-pressure mercury lamp to cure the curable composition (2).

[0137] Subsequently, the PET film was peeled off the cured laminate to obtain a resin laminate in which a cured film was laminated onto a methacrylic resin plate. The same operation was performed on the opposite side, which did not have a cured film, to obtain a resin laminate with cured films laminated on both sides. The evaluation results are shown in Table 2. The TEM observation image is shown in Figure 4. As shown in Figure 4, in Comparative Example 4, the resin substrate layer 4 and the cured film layer 6 were observed, and no mixed layer between them was observed.

[0138] [Table 1]

[0139] [Table 2]

[0140] The resin laminates of Examples 1 to 10 exhibited good scratch resistance, adhesion, impact resistance, warp resistance, heat resistance, and transparency. In contrast, the resin laminate of Comparative Example 1 had insufficient warping resistance because the resin substrate did not have structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in its molecule. In the resin laminate of Comparative Example 2, the cured film did not contain structural units derived from the isocyanurate skeleton, resulting in insufficient impact resistance. In the resin laminate of Comparative Example 3, the content of structural units derived from polymerizable compound (B-1) having two or more (meth)acryloyl groups in the molecule exceeded 40% by mass of the total mass of the resin substrate, resulting in insufficient transparency, adhesion, and impact resistance. In the resin laminate of Comparative Example 4, the curable composition (2) was not exposed to an oxygen-containing atmosphere by the PET film, and therefore did not suffer curing inhibition by oxygen during the curing process. As a result, no mixed layer was formed between the cured film and the resin substrate in the final resin laminate. Consequently, scratch resistance, adhesion, and impact resistance were insufficient. [Industrial applicability]

[0141] The present invention provides a resin laminate with excellent scratch resistance, adhesion, impact resistance, warp resistance, heat resistance, and transparency. The resin laminate can be suitably used, for example, as a front panel for a display that may be exposed to high temperatures. [Explanation of Symbols]

[0142] 1 Hardened film 2 Resin base material 3. Resin laminate 4. Layer of resin substrate 5 Mixed layer 6. Cured coating layer

Claims

1. A sheet-like resin laminate having a cured coating on at least one surface of a resin substrate, The resin laminate further comprises a mixed layer between the cured film and the resin substrate, The mixed layer is formed by mixing the components of the cured film and the resin substrate forming composition that forms the resin substrate with each other. The cured film contains structural units derived from an isocyanurate skeleton represented by the following formula (1): The resin substrate is a resin laminate containing 60% by mass or more of structural units derived from methyl methacrylate, and 0.5% by mass or more and 40% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule. 【Chemistry 1】 In formula (1), R １ Each of these is independently a divalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents, and the three asterisks indicate the bond position.

2. The resin laminate according to claim 1, wherein the film thickness Bt of the mixed layer is 3.0 μm or less.

3. The resin laminate according to claim 1, wherein the film thickness Bt of the mixed layer is 0.1 μm or more and 3.0 μm or less.

4. The resin laminate according to claim 1, wherein the cured film contains a structural unit (A-1) derived from a urethane compound having a (meth)acryloyloxy group, which is a reaction product of a compound (A'-1) represented by the following formula (2) having three isocyanate groups in its molecule and a compound (a'-1) having a hydroxyl group and a (meth)acryloyloxy group in its molecule. 【Chemistry 2】 In formula (2), R １ Each of these is independently a divalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents.

5. The resin laminate according to claim 4, wherein the cured film further contains a structural unit (A-2) derived from a polymerizable compound having three or four (meth)acryloyloxy groups in its molecule, and a structural unit (A-3) derived from a polymerizable compound having two (meth)acryloyloxy groups in its molecule.

6. The content ratio of the structural unit (A-1) is 10% by mass or more and 40% by mass or less of the total mass of the cured film. The content ratio of the structural unit (A-2) is 5% by mass or more and 35% by mass or less of the total mass of the cured film. The resin laminate according to claim 5, wherein the content of the structural unit (A-3) is 40% by mass or more and 65% by mass or less of the total mass of the cured film.

7. The resin laminate according to claim 1, wherein the resin substrate contains 80% by mass or more of structural units derived from methyl methacrylate, and contains 1% by mass or more and 20% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule.

8. The resin laminate according to claim 1, wherein the resin substrate contains 90% by mass or more of structural units derived from methyl methacrylate, and contains 2% by mass or more and 10% by mass or less of structural units derived from a polymerizable compound (B-1) having two or more (meth)acryloyl groups in one molecule.

9. A resin laminate according to claim 1, satisfying both of the following conditions A and B. Condition A: 12 μm ≤ At ≤ 40 μm Condition B: 0.002≦(Bt / At)≦0.3 However, At is the thickness of the cured film, and Bt is the thickness of the mixed layer (μm) measured by the method 1 below. Method 1: The resin laminate is cut perpendicular to the main surface, and then small pieces for transmission electron microscopy are cut from the cut surface using a microtome. For the cut-out pieces, a cross-sectional image of the pieces is obtained using a transmission electron microscope. In the obtained image, the thickness of the mixed layer is measured in the portion where a three-layer structure of resin substrate, mixed layer, and cured film layer is observed, and this is defined as Bt.

10. The resin laminate according to claim 1, wherein the mixed layer is a layer in which the concentration of the resin substrate forming composition increases continuously from the cured film side to the resin substrate side.

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