Laminate and optical member

Abstract

The purpose of the present invention is to provide: a laminate in which peeling of an adhesive in a high-temperature, humidified environment is suppressed; and an optical member comprising the laminate. [Solution] A laminate in which a first substrate and a second substrate are bonded with at least an adhesive layer interposed therebetween, the first substrate and the second substrate having a thickness of 0.6-20 mm, the first substrate containing a methacrylic resin composition, the second substrate containing a methacrylic resin composition, and the third substrate containing a methacrylic resin composition. A silane coupling agent layer is included between the first base material and the adhesive layer, and / or a silane coupling agent layer is included between the second base material and the adhesive layer.

Description

Technical Field

[0001] The present invention relates to a laminate and an optical component. Background Art

[0002] In the past, adhesives were often used to bond lenses, prisms, and various optical components, and transparent adhesives were used to bond the same or different optical materials. For example, Patent Document 1 discloses an optical lens that uses an adhesive to bond multiple lenses with different refractive indices to correct chromatic aberration. Furthermore, Patent Document 2 discloses a resin prism for a polarizing beam splitter, disclosing a cubic polarizing beam splitter fabricated by sandwiching a reflective polarizing film between the hypotenuses of a pair of right-angle prisms and bonding them together.

[0003] On the other hand, various electronic technologies called VR (Virtual Reality) and AR (Augmented Reality) have recently been rapidly developing, and head-mounted display (HMD) products have become popular as image display devices therefor.

[0004] Since HMDs are image display devices mounted on the head, they are required to be compact, lightweight, and minimize discomfort during installation. Therefore, attempts have been made to manufacture resin optical components to reduce the weight of image display devices. Since resins are generally prone to birefringence during molding, a proposal has been made to use low-birefringence methacrylic resins, which are less prone to birefringence, to reduce the birefringence of optical components (lenses, prisms) (Patent Document 3).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-140037.

[0008] Patent document 2: Japanese Patent Application Laid-Open No. 2021-157158.

[0009] Patent Document 3: Japanese Patent Application Publication No. 2018-156081. Summary of the Invention

[0010] Methacrylic resins, used as materials for resin optical components, are known to have high water absorption. However, when adhesives are used to produce laminates containing a methacrylic resin substrate, the methacrylic resin substrate may deform due to moisture absorption, leading to delamination at the adhesive layer interface. Using a laminate with delamination at the adhesive layer as an optical component significantly reduces optical performance (transmittance, polarization separation capability) due to this delamination. Therefore, there is a need for laminates that do not delaminate at the adhesive layer when the resin absorbs water.

[0011] According to studies conducted by the present inventors, particularly when a laminate is produced by bonding other components having a water absorption rate different from that of the methacrylic resin, the different water absorption rates of the methacrylic resin and the other components cause uneven dimensional changes, and thus the bonded portions of the components are susceptible to peeling in a high-temperature and humid environment.

[0012] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a laminate in which peeling of an adhesive is suppressed in a high-temperature and humid environment.

[0013] The present inventors have completed the inventions shown in the following [1] to

[10] after repeated research.

[0014] That is, the present invention is as follows.

[0015] [1] A laminate comprising a first substrate and a second substrate bonded together at least via an adhesive layer, wherein the thickness of the first substrate and the second substrate is 0.6 to 20 mm, the first substrate comprises a methacrylic resin composition, and a silane coupling agent layer is provided between the first substrate and the adhesive layer, and / or a silane coupling agent layer is provided between the second substrate and the adhesive layer.

[0016] [2] The laminate according to [1], wherein the glass transition temperature (Tg) of the methacrylic resin composition is 115°C to 160°C.

[0017] [3] The laminate according to [1] or [2], wherein the absolute value of the photoelastic coefficient of the methacrylic resin composition is 10×10 -12 Pa -1 the following.

[0018] [4] The laminate according to any one of [1] to [3], wherein the methacrylic resin composition contains a methacrylic resin, and the methacrylic resin contains a structural unit having a ring structure.

[0019] [5] The laminate according to [4], wherein the structural unit having a ring structure comprises at least one structural unit selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide-based structural unit, an aromatic vinyl structural unit, an alicyclic vinyl structural unit, and a lactone ring structural unit.

[0020] [6] The laminate according to [4] or [5], wherein the structural unit having a ring structure includes a structural unit derived from an N-substituted maleimide monomer.

[0021] [7] The laminate according to any one of [1] to [6], wherein the second substrate comprises at least one selected from the group consisting of glass, cyclic polyolefin resins, polycarbonate resins, polyester resins, and methacrylic resins.

[0022] [8] The laminate according to any one of [1] to [7], wherein the adhesive layer contains a photocurable acrylic adhesive.

[0023] [9] The laminate as described in any one of [1] to [8], wherein the thickness ratio of the thickest part to the thinnest part of each of the first substrate and the second substrate (thickness of the thickest part / thickness of the thinnest part) is greater than 1.5 and less than 40.

[0024]

[10] An optical component comprising the laminate according to any one of [1] to [9].

[0025] According to the present invention, it is possible to provide a laminate in which peeling of an adhesive is suppressed in a high-temperature and humid environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic plan view of a sample for evaluating adhesive strength used in Examples.

[0027] Figure 2 This is a perspective view of a sample for evaluating adhesive strength used in Examples. DETAILED DESCRIPTION

[0028] Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail. However, the present invention is not limited to the following description, and can be implemented with various modifications within the scope of the gist thereof.

[0029] <Definition>

[0030] In this specification, "high temperature" means a temperature of 50°C or higher.

[0031] In this specification, the term "humidified environment" refers to an environment in which the humidity is artificially increased, and preferably an environment in which the relative humidity is 50% or higher.

[0032] <Laminated body>

[0033] The laminate of this embodiment is characterized in that a first substrate and a second substrate are bonded together via at least an adhesive layer, the thickness of the first substrate and the second substrate is 0.6 to 20 mm, the first substrate comprises a methacrylic resin composition, a silane coupling agent layer is included between the first substrate and the adhesive layer, and / or a silane coupling agent layer is included between the second substrate and the adhesive layer.

[0034] The laminate comprises a silane coupling agent layer between the substrate and the adhesive layer, thereby firmly bonding the substrate and the adhesive layer. This prevents peeling of the adhesive in a high-temperature, humidified environment. Furthermore, this prevents peeling of the adhesive in a high-temperature, humidified environment, thereby suppressing a decrease in optical performance caused by peeling of the adhesive in a high-temperature, humidified environment.

[0035] The laminate of this embodiment may include one or more transparent layers between the first substrate and the silane coupling agent layer, and / or one or more transparent layers between the second substrate and the silane coupling agent layer. Examples of the transparent layer include a hard coat layer and an anchor coat layer. The thickness of these transparent layers is not particularly limited, but may range from 0.01 to 10 μm, for example.

[0036] For example, the surface of the laminate of this embodiment may be further subjected to surface functionalization treatments such as hard coating, antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment. The thickness of these functional layers is not particularly limited, but is generally in the range of 0.01 to 10 μm.

[0037] As a hard coating applied to the surface of the laminate, for example, a silicone curable resin, a curable resin containing an organic polymer composite inorganic particles, an acrylate such as urethane acrylate, epoxy acrylate, and multifunctional acrylate and a photopolymerization initiator are dissolved or dispersed in an organic solvent to obtain a coating liquid, and the coating liquid is applied to the first substrate or the second substrate of the laminate formed in the present embodiment using a conventional coating method, dried, and formed by photocuring. In addition, in order to improve adhesion, for example, a method of forming a hard coating after pre-arranging an easy-adhesion layer, a primer layer, an anchor layer, etc. containing inorganic particles in its composition before applying the hard coating can also be used. As an anti-glare layer applied to its surface, particles such as silicon dioxide, melamine resin, and acrylic resin are made into ink, and the ink is applied to other functional layers using a conventional coating method, and thermally cured or photocured to form. As the anti-reflection layer applied to its surface, there can be cited a layer composed of a thin film of an inorganic substance such as a metal oxide, fluoride, silicide, boride, nitride, sulfide, etc., a layer composed of a single layer or a multilayer stacked of resins with different refractive indices such as acrylic resin, fluororesin, etc. In addition, a layer composed of a stack of thin layers of composite particles containing inorganic compounds and organic compounds can also be used.

[0038] The shape of the bonded portion of the laminate of this embodiment is not particularly limited, and may be a shape in which a portion of the first substrate and the second substrate are bonded together, or a shape in which the entire surface of the first substrate and the second substrate are bonded together.

[0039] The laminate of this embodiment preferably has a peeling area ratio of the adhesive layer of 15% or less when exposed to an environment at a temperature of 60°C and a relative humidity of 90% for 1000 hours. It is more preferably 10% or less, and even more preferably 5% or less. If the peeling area ratio of the adhesive layer is 15% or less when exposed to an environment at a temperature of 60°C and a relative humidity of 90% for 1000 hours, deterioration of optical performance in a high-temperature and humid environment is further suppressed when the laminate is used as an optical component, resulting in a tendency to produce clearer images.

[0040] It should be noted that after exposure to an environment at a temperature of 60°C and a relative humidity of 90% for 1000 hours (high temperature and humidity test), the adhesive layer is observed at a magnification of 100x using a digital microscope VHX-7000 (manufactured by Keyence Corporation, Japan), and the area of ​​the normally bonded portion or the peeled portion is measured to determine the peeled area ratio. Specifically, the method described in the Examples below can be used for measurement.

[0041] <<First base material>>

[0042] The first substrate constituting the laminate of this embodiment comprises a methacrylic resin composition. The methacrylic resin contained in the methacrylic resin composition can be any known methacrylic resin without particular limitation. From the perspective of achieving highly low birefringence properties, the methacrylic resin is preferably composed of a methacrylic resin having a ring structure.

[0043] The thickness of the first substrate is preferably 0.6 to 20 mm, more preferably 0.7 to 20 mm, and even more preferably 1.0 to 10 mm. If the thickness of the first substrate is within this range, the occurrence of poor appearance such as warping and peeling of the adhesive bond after the high-temperature humidity test can be suppressed. The thickness of the first substrate can be measured using the method described in the Examples below.

[0044] The thickness ratio of the thickest portion to the thinnest portion of the first substrate (thickness of the thickest portion / thickness of the thinnest portion) is preferably greater than 1.5 and less than 40, more preferably greater than 1.8 and less than 20, and even more preferably greater than 2.0 and less than 10. If the thickness ratio of the thickest portion to the thinnest portion of the first substrate (thickness of the thickest portion / thickness of the thinnest portion) is within the above range, peeling of the adhesive portion after the high temperature humidity test can be suppressed. The thickness of the first substrate can be measured by the method described in the Examples below.

[0045] (Methacrylic resin composition)

[0046] The methacrylic resin composition contained in the first substrate contains a methacrylic resin. Furthermore, the methacrylic resin composition may optionally contain additives in addition to the methacrylic resin, and may also contain other thermoplastic resins, rubbery polymers, and the like in addition to the methacrylic resin.

[0047] The glass transition temperature (Tg) of the methacrylic resin composition contained in the first substrate, as measured by the midpoint method according to JIS-K7121, is preferably 115 to 160°C. If the glass transition temperature (Tg) of the methacrylic resin composition is 115°C or higher, shape deformation such as warping will not occur during reliability tests such as high-temperature aging tests, and there will be no adverse effects on optical properties. On the other hand, if the glass transition temperature (Tg) is 160°C or lower, melt processing under extremely high temperature conditions is avoided, thermal decomposition of the resin, etc. is suppressed, and a good product can be obtained. From the viewpoint of further obtaining the above-mentioned effects, the glass transition temperature (Tg) is preferably 120 to 145°C, and particularly preferably 125 to 140°C.

[0048] The glass transition temperature of the methacrylic resin composition can be measured using a differential scanning calorimeter (DSC8000, manufactured by Perkin Elmer Japan) in accordance with JIS-K7121. Specifically, it can be measured by the method described in the examples below.

[0049] The photoelastic coefficient (C R ) absolute value |C R |Preferably 10×10 -12 Pa -1 Below, more preferably 5.0×10 -12 Pa -1 Below, more preferably 3.0×10 -12 Pa -1 Below, more preferably 1.0×10 -12 Pa -1 If the photoelastic coefficient (C R ) absolute value |C R |10×10 -12 Pa -1 The photoelastic birefringence of the first substrate is sufficiently low. As a result, the photoelastic birefringence caused by stress and dimensional temperature changes generated when the optical component is fixed to a jig or assembled into an image display device is sufficiently low, and an optical component capable of producing clear images tends to be obtained.

[0050] It should be noted that the photoelastic coefficient (C R ) is measured by pressing a methacrylic resin composition into a film using a vacuum compression molding machine. If a hard coating or anti-reflection coating is applied to the surface of the optical component, these coatings are removed before measurement. Specifically, the α-D-type ...

[0051] The total light transmittance of the methacrylic resin composition contained in the first substrate is preferably 85 to 100%, more preferably 87.5 to 99%, and even more preferably 90 to 99%. If the total light transmittance is within the above range, the laminate can be more suitably used as an optical component.

[0052] In addition, the total light transmittance is a value measured according to JIS K 7361, and can be measured specifically by the method described in Examples to be described later.

[0053] Considering the processability during injection molding, it is preferable that the methacrylic resin composition contained in the first substrate has a low viscosity and high fluidity when injected. -1 Under these conditions, the melt viscosity is preferably 20 to 235 Pa·sec, more preferably 20 to 230 Pa·sec, even more preferably 30 to 180 Pa·sec, and particularly preferably 50 to 150 Pa·sec. When the melt viscosity of the methacrylic resin composition is 20 Pa·sec or higher, the flow of the resin during injection is easily controlled, and molding into the desired shape tends to be easier. On the other hand, when the melt viscosity of the methacrylic resin composition is 235 Pa·sec or lower, the resin exhibits excellent flowability and processability, and molding defects such as poor filling tend to be less likely to occur.

[0054] In addition, the melt viscosity is a value measured according to JIS-K7199, and can be specifically measured by the method described in Examples mentioned later.

[0055] -Methacrylic resin-

[0056] The methacrylic resin contained in the methacrylic resin composition will be described below.

[0057] The methacrylic resin is not particularly limited, and examples thereof include resins primarily composed of structural units derived from methyl methacrylate. Examples of such resins include homopolymers of methyl methacrylate or copolymers of methyl methacrylate with any one or more copolymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate, acrylonitrile, acrylic acid, methacrylic acid, vinylpyridine, vinylmorpholine, vinylpyridonetetrahydrofurfuryl acrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylacrylamide, 2-hydroxyacrylate, ethyl 2-(hydroxymethyl)acrylate, ethylene glycol monoacrylate, glycerol monoacrylate, maleic anhydride, N-cyclohexylmaleimide, N-phenylmaleimide, styrene, and α-methylstyrene. In addition, heat-resistant methacrylic resins having a structural unit derived from methyl methacrylate, a lactone ring, or glutarimide in the main chain, methyl methacrylate, and low-hygroscopic methacrylic resins are also included. These may be used alone or in combination of two or more.

[0058] In addition, "comprising structural units derived from methyl methacrylate as a main component" means that structural units derived from methyl methacrylate account for 50% by mass or more of the structural units in the methacrylic resin.

[0059] From the viewpoint of transparency and heat resistance, the methacrylic resin in the present embodiment is preferably a methacrylic resin containing a structural unit having a ring structure.

[0060] The structural unit having a ring structure preferably comprises at least one structural unit selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide-based structural unit, an aromatic vinyl structural unit, an alicyclic vinyl structural unit, and a lactone ring structural unit. Furthermore, from the perspective of facilitating high-level control of optical properties such as intrinsic birefringence and photoelastic coefficient without mixing with other thermoplastic resins, it is particularly preferred that the structural unit having a ring structure comprises a structural unit derived from an N-substituted maleimide monomer.

[0061] --Structural unit derived from N-substituted maleimide monomer--

[0062] Next, the structural unit derived from the N-substituted maleimide monomer will be described.

[0063] The structural unit derived from the N-substituted maleimide monomer may be at least one structural unit selected from the group consisting of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and is preferably formed from both the structural unit represented by the following formula (1) and the structural unit represented by the following formula (2).

[0064] Chemical formula 1

[0065]

[0066] In formula (1), R 1 represents any one of an arylalkyl group having 7 to 14 carbon atoms and an aryl group having 6 to 14 carbon atoms, and R 2 and R 3 Each independently represents any one of a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms, and an aryl group having 6 to 14 carbon atoms.

[0067] In addition, in R 2 or R 3 In the case of an aryl group, R 2 or R 3 A halogen atom may be contained as a substituent.

[0068] In addition, R 1 It may be substituted with a substituent such as a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, or a benzyl group.

[0069] Chemical formula 2

[0070]

[0071] In formula (2), R 4 represents any one of a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms, and R 5 and R 6 Each independently represents any one of a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms, and an aryl group having 6 to 14 carbon atoms.

[0072] In the above formula (1), the arylalkyl group having 7 to 14 carbon atoms is not limited, and examples thereof include benzyl, phenylethyl, phenylpropyl, naphthylmethyl, naphthylethyl, and naphthylpropyl.

[0073] In the above formulae (1) and (2), the aryl group having 6 to 14 carbon atoms is not limited, and examples thereof include phenyl, tolyl, xylyl, naphthyl, biphenylyl, anthracenyl, and phenanthrenyl.

[0074] In the above formulae (1) and (2), the alkyl group having 1 to 12 carbon atoms may be linear or branched, and is not particularly limited. Examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-methylbutyl, n-pentyl, 2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl, heptyl, n-octyl, 1,1,3,3-tetramethylbutyl, 2-ethylhexyl, nonyl, decyl, undecyl, and dodecyl.

[0075] In the above formula (1), examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0076] In the above formula (1), the alkoxy group having 1 to 6 carbon atoms is not limited, and examples thereof include methoxy, ethoxy, n-butoxy, and methoxyethoxy.

[0077] In the above formula (1), the cycloalkyl group having 3 to 12 carbon atoms is not limited, and examples thereof include cyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, trimethylcyclohexyl, thujyl, norbornyl, bornyl, norcaryl, caryl, menthyl, norpinyl, pinyl, 1-adamantyl, and 2-adamantyl.

[0078] Specific examples of the monomer forming the structural unit represented by the above formula (1) and the monomer forming the structural unit represented by the above formula (2) are shown below.

[0079] Examples of monomers (N-arylmaleimides, N-aromatic substituted maleimides, etc.) forming the structural unit represented by formula (1) include N-phenylmaleimide, N-benzylmaleimide, N-(2-chlorophenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, N-(2-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2-ethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N- -(2-nitrophenyl)maleimide, N-(2,4,6-trimethylphenyl)maleimide, N-(4-benzylphenyl)maleimide, N-(2,4,6-tribromophenyl)maleimide, N-naphthylmaleimide, N-anthrylmaleimide, 3-methyl-1-phenyl-1H-pyrrole-2,5-dione, 3,4-dimethyl-1-phenyl-1H-pyrrole-2,5-dione, 1,3-diphenyl-1H-pyrrole-2,5-dione, 1,3,4-triphenyl-1H-pyrrole-2,5-dione, etc.

[0080] Among these monomers, N-phenylmaleimide and N-benzylmaleimide are preferred from the viewpoint of excellent optical properties such as heat resistance and birefringence.

[0081] These monomers may be used alone or in combination of two or more.

[0082] Examples of the monomer forming the structural unit represented by formula (2) include N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-sec-butylmaleimide, N-tert-butylmaleimide, N-n-pentylmaleimide, N-n-hexylmaleimide, N-n-heptylmaleimide, N- -n-octylmaleimide, N-laurylmaleimide, N-cyclopentylmaleimide, N-cyclohexylmaleimide, 1-cyclohexyl-3-methyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-dimethyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3-phenyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-diphenyl-1H-pyrrole-2,5-dione, etc.

[0083] Among these monomers, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide are preferred monomers from the viewpoint of excellent weather resistance of methacrylic resins. N-cyclohexylmaleimide is particularly preferred from the viewpoint of excellent low hygroscopicity required for optical materials in recent years.

[0084] These monomers may be used alone or in combination of two or more.

[0085] In the methacrylic resin in the methacrylic resin composition, it is particularly preferred to use the structural unit represented by formula (1) and the structural unit represented by formula (2) in combination, from the viewpoint of being able to express highly controlled birefringence characteristics.

[0086] The molar ratio (X1 / X2) of the content (X1) of the structural unit represented by formula (1) to the content (X2) of the structural unit represented by formula (2) is preferably greater than 0 and 15 or less, and more preferably greater than 0 and 10 or less. When the molar ratio (X1 / X2) is within this range, the laminate and optical component of the present embodiment maintain transparency without yellowing, and exhibit good heat resistance and good photoelastic properties without impairing environmental resistance.

[0087] The content of the structural units derived from the N-substituted maleimide monomer in the methacrylic resin is preferably 5-40% by mass, and more preferably 5-35% by mass, based on 100% by mass of the methacrylic resin. When the content of the structural units derived from the N-substituted maleimide monomer is within the range of 5-40% by mass, based on 100% by mass of the methacrylic resin, the methacrylic resin can achieve a more sufficient improvement in heat resistance and further improve weather resistance, low water absorption, and optical properties. It should be noted that setting the content of the structural units derived from the N-substituted maleimide monomer to 40% by mass or less is effective in preventing a decrease in the reactivity of the monomer components during the polymerization reaction and an increase in the amount of unreacted residual monomer, which can lead to a decrease in the physical properties of the methacrylic resin.

[0088] Furthermore, by appropriately adjusting the content of structural units derived from an N-substituted maleimide monomer to 5-40% by mass, with the methacrylic resin as 100% by mass, birefringence caused by orientation and residual stress during molding is reduced, resulting in a first substrate comprising a methacrylic resin composition having an average absolute value of in-plane retardation of 10 nm or less. The most suitable content of structural units derived from an N-substituted maleimide monomer varies depending on the type of N-substituted maleimide. For example, when methyl methacrylate is used as the methacrylate monomer and N-phenylmaleimide and N-cyclohexylmaleimide are used as the N-substituted maleimide monomers, it is preferred that the content of structural units derived from methyl methacrylate be adjusted to 79-83% by mass, the content of structural units derived from N-phenylmaleimide be adjusted to 6-8% by mass, and the content of structural units derived from N-cyclohexylmaleimide be adjusted to 11-13% by mass.

[0089] The methacrylic resin having a structural unit derived from an N-substituted maleimide monomer may contain a structural unit derived from another monomer copolymerizable with the methacrylate monomer and the N-substituted maleimide monomer, within the range not impairing the purpose of the present invention.

[0090] For example, examples of the other copolymerizable monomers include aromatic vinyl groups; unsaturated nitriles; acrylic acid esters having a cyclohexyl group, a benzyl group, or an alkyl group having 1 to 18 carbon atoms; glycidyl compounds; and unsaturated carboxylic acids.

[0091] Examples of the aromatic vinyl group include styrene, α-methylstyrene, and divinylbenzene.

[0092] Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, and ethacrylonitrile.

[0093] Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate.

[0094] Examples of the glycidyl compound include glycidyl (meth)acrylate and the like.

[0095] Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and half-esters or anhydrides thereof.

[0096] The structural unit derived from the above-mentioned other copolymerizable monomer may be present in only one type or in two or more types.

[0097] The content of the structural units derived from other copolymerizable monomers is preferably 0 to 10% by mass, more preferably 0 to 9% by mass, and even more preferably 0 to 8% by mass, based on 100% by mass of the methacrylic resin.

[0098] If the content of the structural unit derived from other monomers is within this range, the moldability and mechanical properties of the resin can be improved without impairing the original effect of the introduction of the ring structure, which is preferred.

[0099] It should be noted that the content of the structural unit derived from the N-substituted maleimide monomer and the content of the structural unit derived from other copolymerizable monomers can be expressed by 1 H-NMR determination and 13 For example, deuterated chloroform (CDCl3) or deuterated dimethyl sulfoxide (DMSO-d6) can be used as a measurement solvent and the measurement temperature can be 40°C. 1 H-NMR determination and 13 C-NMR determination.

[0100] --Glutarimide-based structural units--

[0101] Examples of the methacrylic resin having a glutarimide structural unit include methacrylic resins having a glutarimide structural unit described in JP-A-2006-249202, JP-A-2007-009182, JP-A-2007-009191, JP-A-2011-186482, and Japanese Re-Patent No. 2012 / 114718. These can be formed by the methods described in these publications.

[0102] The glutarimide structural unit constituting the methacrylic resin can be formed after the resin is polymerized.

[0103] Specifically, the glutarimide-based structural unit may be a structural unit represented by the following formula (3).

[0104] Chemical formula 3

[0105]

[0106] In the above formula (3), it is preferred that R 7 and R 8 are independently a hydrogen atom or a methyl group, R 9 is any one of a hydrogen atom, a methyl group, a butyl group and a cyclohexyl group, more preferably, R 7 is methyl, R 8 is a hydrogen atom, R 9 It is a methyl group.

[0107] The glutarimide-based structural units may be contained in one type or in a plurality of types.

[0108] In the methacrylic resin having a glutarimide structural unit, the content of the glutarimide structural unit is preferably in the range of 3 to 70 mass %, more preferably in the range of 3 to 60 mass %, based on 100 mass % of the methacrylic resin.

[0109] When the content of the glutarimide structural unit is within the above range, a resin having excellent molding processability, heat resistance, and optical properties can be obtained, which is preferred.

[0110] Furthermore, by appropriately adjusting the content of the glutarimide structural unit within this range, birefringence caused by orientation and residual stress during molding is reduced, and a first substrate comprising a methacrylic resin composition having an average absolute value of in-plane retardation of 5 nm or less can be obtained. The most suitable content of the glutarimide structural unit is determined by R in formula (3). 7 ~R 9 The type of substituents varies. For example, when R 7 and R 8 is a hydrogen atom and R 9 In the case of a methyl group, when the content of the glutarimide structural unit is within the range of 3 to 10% by mass, birefringence caused by orientation and residual stress during molding is reduced, and a first substrate comprising a methacrylic resin composition having an average absolute value of the in-plane retardation of 10 nm or less can be obtained.

[0111] The content of the glutarimide structural unit in the methacrylic resin can be determined using a method described in patent documents such as JP-A-2006-249202.

[0112] The methacrylic resin having a glutarimide structural unit may further contain an aromatic vinyl monomer unit as needed.

[0113] The aromatic vinyl monomer is not particularly limited, and examples thereof include styrene and α-methylstyrene, with styrene being preferred.

[0114] The content of the aromatic vinyl unit in the methacrylic resin having a glutarimide structural unit is not particularly limited, but is preferably 0 to 20% by mass based on 100% by mass of the methacrylic resin having a glutarimide structural unit.

[0115] When the content of the aromatic vinyl unit is within the above range, both heat resistance and excellent photoelastic properties can be achieved, which is preferred.

[0116] For example, when a methyl methacrylate-styrene copolymer is obtained by copolymerizing methyl methacrylate as a methacrylate monomer and styrene as an aromatic vinyl monomer, and this methyl methacrylate-styrene copolymer is glutarimidized to obtain a resin, by adjusting the content of structural units derived from methyl methacrylate to 65 to 90% by mass, the content of structural units derived from styrene to 5 to 15% by mass, and the content of glutarimide-based structural units to 5 to 20% by mass, birefringence caused by orientation and residual stress during molding can be reduced, and a first substrate comprising a methacrylic resin composition having an average absolute value of in-plane retardation of 10 nm or less can be obtained.

[0117] --Aromatic vinyl structural unit--

[0118] The aromatic vinyl structural unit is not particularly limited, and examples thereof include a structural unit derived from styrene and a structural unit derived from α-methylstyrene. A structural unit derived from styrene is preferred.

[0119] --Alicyclic vinyl structural unit--

[0120] The alicyclic vinyl structural unit can be formed by the methods described in, for example, JP-A-2006-291184, JP-A-2006-291184, JP-A-2014-77043, and JP-A-2014-77044.

[0121] --Lactone ring structural unit--

[0122] The methacrylic resin having a lactone ring structural unit can be formed by the methods described in, for example, JP-A-2001-151814, JP-A-2004-168882, JP-A-2005-146084, JP-A-2006-96960, JP-A-2006-171464, JP-A-2007-63541, JP-A-2007-297620, and JP-A-2010-180305.

[0123] The lactone ring structural unit constituting the methacrylic resin may be formed after the resin is polymerized.

[0124] The lactone ring structural unit in the present embodiment is preferably a six-membered ring from the viewpoint of excellent stability of the ring structure.

[0125] As the six-membered lactone ring structural unit, for example, a structure represented by the following formula (4) is particularly preferred.

[0126] Chemical formula 4

[0127]

[0128] In the above formula (4), R 10 、R 11 and R 12 They are independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms.

[0129] Examples of the organic residue include saturated aliphatic hydrocarbon groups (alkyl groups, etc.) having 1 to 20 carbon atoms, such as methyl, ethyl, and propyl groups; unsaturated aliphatic hydrocarbon groups (alkenyl groups, etc.) having 2 to 20 carbon atoms, such as vinyl and propenyl groups; aromatic hydrocarbon groups (aryl groups, etc.) having 6 to 20 carbon atoms, such as phenyl and naphthyl groups; groups in which one or more hydrogen atoms in these saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, and aromatic hydrocarbon groups are substituted by at least one group selected from the group consisting of a hydroxyl group, a carboxyl group, an ether group, and an ester group; and the like.

[0130] The lactone ring structural unit can be formed as follows, for example, by copolymerizing an acrylic monomer having a hydroxyl group and a methacrylate monomer such as methyl methacrylate to introduce a hydroxyl group and an ester group or a carboxyl group into the molecular chain, and then allowing these hydroxyl groups and the ester group or the carboxyl group to undergo dealcoholization (esterification) or dehydration condensation (hereinafter also referred to as "cyclization condensation reaction").

[0131] Examples of acrylic monomers having a hydroxyl group used for polymerization include 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid, 2-(hydroxymethyl)acrylic acid alkyl esters (e.g., methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, tert-butyl 2-(hydroxymethyl)acrylate), and 2-(hydroxyethyl)acrylic acid alkyl esters. Preferred are monomers having a hydroxyalkyl moiety, i.e., 2-(hydroxymethyl)acrylic acid and 2-(hydroxymethyl)acrylic acid alkyl esters, and particularly preferred are methyl 2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate.

[0132] The content of the lactone ring structural unit in the methacrylic resin having a lactone ring structural unit is preferably 5 to 40% by mass, more preferably 5 to 35% by mass, relative to 100% by mass of the methacrylic resin.

[0133] When the content of the lactone ring structural unit is 5 to 40% by mass relative to 100% by mass of the methacrylic resin, the effects of the ring structure introduction, such as improved solvent resistance and surface hardness, can be achieved while maintaining moldability. Furthermore, by appropriately adjusting the content of the lactone ring structural unit to within the range of 5 to 40% by mass relative to 100% by mass of the methacrylic resin, birefringence caused by orientation and residual stress during molding is reduced, resulting in a first substrate comprising a methacrylic resin having an average absolute value of in-plane retardation of 10 nm or less.

[0134] The content of the lactone ring structure in the methacrylic resin can be determined using a method described in patent documents such as the aforementioned Japanese Patent Application Laid-Open No. 2001-151814.

[0135] The methacrylic resin having a lactone ring structural unit may further have a structural unit derived from another monomer copolymerizable with the above-mentioned methacrylate monomer and the acrylic monomer having a hydroxyl group.

[0136] Examples of such other copolymerizable monomers include monomers having polymerizable double bonds such as styrene, vinyltoluene, α-methylstyrene, α-hydroxymethylstyrene, α-hydroxyethylstyrene, acrylonitrile, methacrylonitrile, methallyl alcohol, ethylene, propylene, 4-methyl-1-pentene, vinyl acetate, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinylpyrrolidone, and N-vinylcarbazole.

[0137] These other monomers (constituent units) may be present in one type or in two or more types.

[0138] The content of the structural units derived from other copolymerizable monomers is preferably 0 to 20% by mass relative to 100% by mass of the methacrylic resin, more preferably less than 10% by mass, and even more preferably less than 7% by mass from the viewpoint of weather resistance.

[0139] The methacrylic resin in the present embodiment may have only one type of structural unit derived from the above-mentioned other copolymerizable monomer, or may have two or more types.

[0140] [Method for producing methacrylic resin]

[0141] Hereinafter, the method for producing the methacrylic resin according to the present embodiment will be described.

[0142] In the production method of methacrylic resin, the polymerization method that can be used includes batch, semi-batch, and continuous methods. Here, the batch method refers to a process in which the total amount of raw materials is added to the reactor, the reaction is started and continued, and the product is recovered after completion. In addition, the semi-batch method refers to a process in which either raw materials are added or product is recovered simultaneously during the reaction. Furthermore, the continuous method refers to a process in which both raw materials are added and product is recovered simultaneously during the reaction. As a method for producing methacrylic resin, from the perspective of precisely controlling the copolymer composition, the semi-batch method in which a portion of the raw materials are added after the reaction begins is preferred.

[0143] In addition, a continuous process can be used, but as a method for producing methacrylic resin, it is preferably not used for the following reasons. When a complete mixing reactor is used to carry out the polymerization reaction, there is an advantage of being able to reduce the difference in monomer composition between each fraction with different molecular weights in the methacrylic resin. However, since a lot of unreacted monomers remain after polymerization, there is a tendency to have a negative impact on the color tone. On the other hand, when a plug flow reactor is used, the amount of unreacted monomers can be reduced, but the difference in monomer composition between each fraction with different molecular weights in the methacrylic resin tends to increase. When a plurality of complete mixing reactors or a complete mixing reactor and a plug flow reactor are combined in series, the amount of unreacted monomers can also be reduced, but the difference in monomer composition between the above-mentioned components tends to increase.

[0144] The polymerization method of the methacrylic resin is not particularly limited, and examples thereof include emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, and cationic polymerization.

[0145] The polymerization solvent is not particularly limited. Examples of the polymerization solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and cumene; esters such as methyl isobutyrate; ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone; and polar solvents such as dimethylformamide and 2-methylpyrrolidone.

[0146] Furthermore, an alcohol such as methanol, ethanol, or isopropyl alcohol may be used in combination as a polymerization solvent within a range that does not inhibit the dissolution of the polymerization product during polymerization.

[0147] The amount of solvent used during polymerization is not particularly limited as long as the polymerization can proceed, the copolymer or the monomers used do not precipitate during production, and the amount can be easily removed. For example, based on 100 parts by mass of the total amount of the monomers to be blended, the amount is preferably 10 to 200 parts by mass, more preferably 25 to 200 parts by mass, further preferably 50 to 200 parts by mass, and even more preferably 50 to 150 parts by mass.

[0148] As the polymerization initiator, any initiator commonly used in free radical polymerization can be used, for example, organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-tert-butyl peroxide, lauroyl peroxide, benzoyl peroxide, tert-butyl peroxyisopropyl carbonate, tert-amyl peroxy-2-ethylhexanoate, tert-amyl peroxyisononanoate, and 1,1-di(tert-butylperoxy)cyclohexane; azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobisisobutyrate; etc.

[0149] These may be used alone or in combination of two or more.

[0150] These polymerization initiators may be added at any stage as long as the polymerization reaction is proceeding.

[0151] The amount of the polymerization initiator added may be 0.01 to 1 part by mass, preferably 0.05 to 0.5 parts by mass, based on 100 parts by mass of the total amount of the monomers used in the polymerization.

[0152] As the chain transfer agent, a chain transfer agent commonly used in free radical polymerization can be used, for example, thiol compounds such as n-butyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, 2-ethylhexyl thioglycolate; halogen compounds such as carbon tetrachloride, dichloromethane, bromoform; unsaturated hydrocarbon compounds such as α-methylstyrene dimer, α-terpinene, dipentene, terpinolene; etc.

[0153] These may be used alone or in combination of two or more.

[0154] These chain transfer agents may be added at any stage as long as the polymerization reaction proceeds, and are not particularly limited.

[0155] The amount of the chain transfer agent added may be 0.01 to 1 part by mass, preferably 0.05 to 0.5 parts by mass, based on 100 parts by mass of the total amount of the monomers used in the polymerization.

[0156] There are no particular limitations on the method for recovering a polymer from a polymerization solution obtained by solution polymerization. For example, there may be a method in which the polymerization solution is added in the presence of an excess of a poor solvent such as a hydrocarbon solvent or an alcohol solvent in which the polymerization product obtained by the polymerization is not dissolved, followed by treatment with a homogenizer (emulsification dispersion), and unreacted monomers are subjected to pretreatment such as liquid-liquid extraction or solid-liquid extraction to separate them from the polymerization solution; or a method in which the polymerization solvent and unreacted monomers are separated through a process called a devolatilization process, and the polymerization product is recovered; etc.

[0157] Here, the devolatilization step refers to a step of removing volatile components such as the polymerization solvent, residual monomers, and reaction by-products under heating and reduced pressure conditions.

[0158] As the apparatus used in the devolatilization process, for example, there can be cited a devolatilization apparatus consisting of a tubular heat exchanger and a devolatilization tank; thin film evaporators such as Wiprene and Exeva manufactured by Kobelco Eco Solutions, and KONTRO and tilted-wing KONTRO manufactured by Hitachi, Ltd.; an extruder with a vent having a residence time and a surface area sufficient to exhibit devolatilization performance; etc.

[0159] A devolatilization step using a devolatilization device in which two or more of these devices are combined can also be utilized.

[0160] From the viewpoint of improving color tone, it is preferred to use a devolatilizer mainly composed of a heat exchanger and a decompression container and having no rotating part in its structure.

[0161] Specifically, a devolatilization device can be used, which is composed of a devolatilization tank with a heat exchanger disposed on its upper portion and a decompression mechanism attached to a decompression container of a size capable of devolatilization; and a discharge device such as a gear pump for discharging the devolatilized polymer.

[0162] The devolatilization apparatus described above preheats the polymerization solution by feeding it to a heated heat exchanger located above the reduced-pressure vessel. The solution is then fed to a heated, reduced-pressure devolatilization tank to separate and remove the polymerization solvent, unreacted raw material mixture, polymerization by-products, and the like from the copolymer. Examples of such heat exchangers include multi-tubular heat exchangers, plate-fin heat exchangers, and plate-type heat exchangers with flat-plate flow paths and heaters. Using a devolatilization apparatus without a rotating section as described above is preferred because it allows for the production of a methacrylic resin with a good hue.

[0163] The treatment temperature in the devolatilizer is preferably 150 to 350° C., more preferably 170 to 300° C., and even more preferably 200 to 280° C. By setting the temperature at or above the lower limit, residual volatile components can be suppressed, while by setting the temperature at or below the upper limit, coloration and decomposition of the resulting methacrylic resin can be suppressed.

[0164] -additive-

[0165] The methacrylic resin composition contained in the first substrate may contain various additives within a range not significantly impairing the effects of the present invention.

[0166] The additives are not particularly limited, and examples thereof include antioxidants, light stabilizers such as hindered amine light stabilizers, ultraviolet absorbers, release agents, thermoplastic resins other than methacrylic resins, paraffinic process oils, naphthenic process oils, aromatic process oils, paraffin waxes, organopolysiloxanes, mineral oils and other softeners / plasticizers, flame retardants, antistatic agents, inorganic fillers such as organic fibers and pigments such as iron oxide, reinforcing agents such as glass fibers, carbon fibers, and metal whiskers, colorants, organic phosphorus compounds such as phosphites, phosphonites, and phosphates, and mixtures thereof.

[0167] --Antioxidants--

[0168] The methacrylic resin composition contained in the first substrate preferably contains an antioxidant for suppressing degradation and coloration during molding or use.

[0169] The antioxidant is not limited to the following substances, and examples thereof include hindered phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. For the methacrylic resin composition of this embodiment, in order to effectively control surface deformation and warping of the molded article, it is important to maintain the resin at a high temperature within the mold cavity and to provide an appropriate cooling time. When subjected to a long thermal history, the amount of heat stabilizer added may need to be increased to achieve the desired thermal stability. However, from the perspective of suppressing heat stabilizer exudation and preventing adhesion to the mold, it is preferable to use multiple heat stabilizers in combination. For example, it is preferable to use at least one selected from a phosphorus-based antioxidant and a sulfur-based antioxidant in combination with a hindered phenol-based antioxidant.

[0170] These antioxidants may be used alone or in combination of two or more.

[0171] The hindered phenol antioxidant is not limited to the following substances, and examples thereof include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], diethylenethiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 6-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamine)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, and the like.

[0172] In particular, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate are preferred.

[0173] Furthermore, as the hindered phenol-based antioxidant, a commercially available phenol-based antioxidant may be used. Such commercially available phenol-based antioxidants are not limited to the following substances, and examples thereof include Irganox 1010 (Irganox 1010: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by BASF), Irganox 1076 (Irganox 1076: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, manufactured by BASF), Irganox 1330 (Irganox 1330: 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6-triyl)tri-p-cresol, manufactured by BASF), Irganox 3114 (Irganox 3115: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, manufactured by BASF), 3114: 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, manufactured by BASF), Irganox 3125 (Irganox 3125, manufactured by BASF), ADK STAB AO-60 (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by ADEKA), ADK STAB AO-80 (3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, manufactured by ADEKA), Sumilizer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical Co., Ltd.), Cyanox 1790 (Cyanox 1790, manufactured by SAITEC CO., Ltd.), Sumilizer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer GS (Sumilizer GS: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer GM (Sumilizer GM: 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), vitamin E (manufactured by Eisai Co., Ltd.), and the like.

[0174] Among these commercially available phenolic antioxidants, Irganox 1010, ADK STAB AO-60, ADK STAB AO-80, Irganox 1076, Sumilizer GS, and the like are also preferred from the viewpoint of the effect of imparting thermal stability to the resin.

[0175] These may be used alone or in combination of two or more.

[0176] In addition, the phosphorus-based antioxidant is not limited to the following substances, and examples thereof include tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethylphosphite, tetrakis(2,4-di-tert-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) diphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, tetrakis(2,4-tert-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphonite, di-tert-butyl-m-tolyl-phosphonite, 4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphinocycloheptene)-6-yloxy]propyl]-2-methyl-6-tert-butylphenol, and the like.

[0177] Furthermore, as the phosphorus-based antioxidant, a commercially available phosphorus-based antioxidant may be used. Such commercially available phosphorus-based antioxidants are not limited to the following substances, and examples thereof include Irgafos 168 (Irgafos 168: tris(2,4-di-tert-butylphenyl)phosphite, manufactured by BASF), Irgafos 12 (Irgafos 12: tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphin-6-yl]oxy]ethyl]amine, manufactured by BASF), Irgafos 38 (Irgafos 38: bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethylphosphite, manufactured by BASF), ADK STAB 329K (ADK STAB-229K, manufactured by ADEKA), ADK STAB PEP-36 (ADK STAB PEP-36, manufactured by ADEKA), ADK STAB PEP-36A (ADK STAB PEP-36A, manufactured by ADEKA), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by ADEKA), ADK STAB HP-10 (ADK STAB HP-10, manufactured by ADEKA), ADK STAB 2112 (ADK STAB 2112, manufactured by ADEKA), ADK STAB 1178 (ADK STAB 1178, manufactured by ADEKA), ADK STAB 1500 (ADK STAB 1500, manufactured by ADEKA), Sandstab P-EPQ (manufactured by Clariant), Weston 618 (manufactured by General Electric Company (GE)), Weston 619G (manufactured by General Electric Company (GE)), Ultranox 626 (manufactured by General Electric Company (GE)), Sumilizer GP (Sumilizer GP: 4-[3-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphinylcycloheptene)-6-yloxy]propyl]-2-methyl-6-tert-butylphenol, manufactured by Sumitomo Chemical Co., Ltd.), HCA (9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide, manufactured by Sanko Co., Ltd.), and the like.

[0178] Among these commercially available phosphorus-based antioxidants, Irgafos 168, ADK STAB PEP-36, ADK STAB PEP-36A, ADK STAB HP-10, and ADK STAB 1178 are preferred from the viewpoint of the effect of imparting thermal stability to the resin and the effect of combined use with multiple antioxidants, and ADK STAB PEP-36A and ADK STAB PEP-36 are particularly preferred.

[0179] These phosphorus-based antioxidants may be used alone or in combination of two or more.

[0180] The sulfur-based antioxidant is not limited to the following substances, and examples thereof include 2,4-bis(dodecylthiomethyl)-6-methylphenol (Irganox 1726, manufactured by BASF), 2,4-bis(octylthiomethyl)-6-methylphenol (Irganox 1520L, manufactured by BASF), 2,2-bis{[3-(dodecylthio)-1-oxypropoxy]methyl}propane-1,3-diylbis[3-dodecylthio]propionate] (ADK STAB AO-412S, manufactured by ADEKA), 2,2-bis{[3-(dodecylthio)-1-oxypropoxy]methyl}propane-1,3-diylbis[3-dodecylthio]propionate] (KEMINOX PLS, manufactured by CHEMIPRO KASEI Co., Ltd.), and 2,2-bis{[3-(dodecylthio)-1-oxypropoxy]methyl}propane-1,3-diylbis[3-dodecylthio]propionate] (KEMINOX PLS, manufactured by CHEMIPRO KASEI Co., Ltd.). KAISHA, LTD.), ditridecyl 3,3'-thiodipropionate (AO-503, ADEKA), etc.

[0181] Among these commercially available sulfur antioxidants, ADK STAB AO-412S and CHEMINOX PLS are also preferred from the viewpoints of the effect of imparting thermal stability to the methacrylic resin composition, the effect of combined use with multiple antioxidants, and the viewpoint of handleability.

[0182] These sulfur-based antioxidants may be used alone or in combination of two or more.

[0183] The content of the antioxidant in the methacrylic resin composition may be an amount sufficient to achieve the effect of improving thermal stability. However, if the content is excessive, there is a concern that problems such as bleeding may occur during processing. Therefore, the content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, still more preferably 0.8 part by mass or less, further preferably 0.01 to 0.8 part by mass, and particularly preferably 0.01 to 0.5 part by mass, relative to 100 parts by mass of the methacrylic resin.

[0184] --Hindered Amine Light Stabilizer--

[0185] The methacrylic resin composition may contain a hindered amine light stabilizer.

[0186] The hindered amine light stabilizer is not particularly limited, but is preferably a compound containing three or more ring structures. The ring structure is preferably at least one selected from the group consisting of an aromatic ring, an aliphatic ring, an aromatic heterocycle, and a non-aromatic heterocycle. When a compound has two or more ring structures, the ring structures may be the same or different.

[0187] The hindered amine light stabilizer is not limited to the following substances, and specific examples thereof include bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidinyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, Ester, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-N,N'-diformylhexamethylenediamine, polycondensate of dibutylamine-1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidinyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{2,2,6, 6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}], tetrakis(1,2,2,6,6-pentamethyl-4-piperidinyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidinyl)butane-1,2,3,4-tetracarboxylate, 1,2,2,6,6-pentamethyl-4-piperidinol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[ [5.5]undecane-3,9-diethanol reaction product, 2,2,6,6-tetramethyl-4-piperidinol reaction product with β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, bis(1-undecyloxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, 2,2,6,6-tetramethyl-4-piperidinyl methacrylate, etc.

[0188] Among them, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate containing three or more ring structures, polycondensation products of dibutylamine-1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidinyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}], the reaction product of 1,2,2,6,6-pentamethyl-4-piperidinol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, and the reaction product of 2,2,6,6-tetramethyl-4-piperidinol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol.

[0189] The content of the hindered amine light stabilizer may be any amount sufficient to achieve the effect of improving the light stability. However, if the content is excessive, there is a concern that problems such as bleeding may occur during processing. Therefore, the content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, still more preferably 0.8% by mass or less, further preferably 0.01 to 0.8% by mass, and particularly preferably 0.01 to 0.5% by mass, relative to 100% by mass of the methacrylic resin.

[0190] --UV absorber--

[0191] The methacrylic resin composition of the present embodiment may contain an ultraviolet absorber.

[0192] The ultraviolet absorber is not particularly limited, but preferably has a maximum absorption wavelength of 280 to 380 nm. Examples thereof include benzotriazole compounds, benzotriazine compounds, benzophenone compounds, oxybenzophenone compounds, benzoate compounds, phenol compounds, oxazole compounds, cyanoacrylate compounds, and benzoxazinone compounds.

[0193] These ultraviolet absorbers may be used alone or in combination of two or more.

[0194] As the ultraviolet absorber, particularly from the viewpoint of compatibility with the resin and volatility during heating, benzotriazole compounds and benzotriazine compounds having a molecular weight of 400 or more are preferred. Furthermore, from the viewpoint of suppressing decomposition of the ultraviolet absorber itself due to heating during extrusion processing, benzotriazine compounds are particularly preferred.

[0195] The content of the ultraviolet absorber is not particularly limited as long as it is an amount that does not impair heat resistance, moisture-heat resistance, thermal stability, and moldability and can exhibit the effects of the present invention. However, it is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, more preferably 0.25 to 3 parts by mass, and even more preferably 0.3 to 3 parts by mass, relative to 100 parts by mass of the methacrylic resin. When the content of the ultraviolet absorber is within this range, an excellent balance between ultraviolet absorption performance and moldability is achieved.

[0196] --Release agent--

[0197] The methacrylic resin composition of this embodiment may contain a release agent. Examples of the release agent include, but are not limited to, fatty acid esters, fatty acid amides, fatty acid metal salts, hydrocarbon lubricants, alcohol lubricants, polyalkylene glycols, carboxylic acid esters, and hydrocarbon paraffinic mineral oils.

[0198] These release agents may be used alone or in combination of two or more.

[0199] There are no particular limitations on the fatty acid esters that can be used as the release agent, and conventionally known fatty acid esters can be used.

[0200] As fatty acid esters, for example, ester compounds of fatty acids having 12 to 32 carbon atoms, such as lauric acid, palmitic acid, margaric acid, stearic acid, oleic acid, arachidic acid, and behenic acid, and monohydric aliphatic alcohols such as palmityl alcohol, stearyl alcohol, and behenyl alcohol, or polyhydric aliphatic alcohols such as glycerol, pentaerythritol, dipentaerythritol, and sorbitan; and complex ester compounds of fatty acids with polybasic organic acids and monohydric aliphatic alcohols or polyhydric aliphatic alcohols can be used.

[0201] Examples of such fatty acid ester lubricants include cetyl palmitate, butyl stearate, stearyl stearate, stearyl citrate, glyceryl monocaprylate, glyceryl monocaprate, glyceryl monolaurate, glyceryl monopalmitate, glyceryl dipalmitate, glyceryl monostearate, glyceryl distearate, glyceryl tristearate, glyceryl monooleate, glyceryl dioleate, glyceryl trioleate, glyceryl monolinoleate, glyceryl monobehenate, glyceryl mono-12-hydroxystearate, glyceryl di-12-hydroxystearate, glyceryl tri-12-hydroxystearate, glyceryl diacetyl monostearate, glyceryl citric acid fatty acid ester, pentaerythritol adipic acid stearate, montanic acid partially saponified ester, pentaerythritol tetrastearate, dipentaerythritol hexastearate, and sorbitan tristearate.

[0202] These fatty acid ester lubricants may be used alone or in combination of two or more.

[0203] Examples of commercially available fatty acid ester lubricants include the RIKEMAL series, POEM series, RIKESTAR series, and RIKEMASTER series manufactured by Riken Vitamin Co., Ltd.; the EXCEL series, RHEODOL series, EXCEPARL series, and COCONAD series manufactured by Kao Corporation; and more specifically, RIKEMAL S-100, RIKEMAL H-100, and POEM series. RIKEMAL S-200 (リケマールS-200), POEM B-200 (ポエムB-200), RIKESTAR EW-200 (リケスターEW-200), RIKESTAR EW-400(リケスターEW-400), EXCEL S-95(エキセルS-95), RHEODOL MS-50(レオドールMS-50), etc.

[0204] The amount of release agent can be any amount sufficient to achieve its effectiveness as a release agent. However, excessive amounts may cause problems such as bleed-out and screw slippage during processing, leading to extrusion failure. Therefore, the amount of release agent is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, even more preferably 0.01 to 0.8 parts by mass, and particularly preferably 0.01 to 0.5 parts by mass, relative to 100 parts by mass of the methacrylic resin. Addition of the release agent within this range not only suppresses the reduction in transparency caused by the addition of the release agent, but also tends to suppress release failure during injection molding.

[0205] --Other thermoplastic resins--

[0206] The methacrylic resin composition of the present embodiment may further contain other thermoplastic resins in addition to the methacrylic resin for the purpose of adjusting birefringence and improving flexibility, within a range not impairing the purpose of the present invention.

[0207] Other thermoplastic resins include, for example, polyacrylates such as polybutyl acrylate; styrene-based polymers such as polystyrene, styrene-methyl methacrylate copolymers, styrene-butyl acrylate copolymers, styrene-acrylonitrile copolymers, and acrylonitrile-butadiene-styrene block copolymers. Furthermore, for example, acrylic rubber particles having a three- to four-layer structure as described in Japanese Patent Application Laid-Open Nos. 59-202213, 63-27516, 51-129449, and 52-56150; rubber polymers disclosed in Japanese Patent Application Laid-Open Nos. 60-17406 and 8-245854; and methacrylic rubber-containing graft copolymer particles obtained by multi-stage polymerization as described in International Publication No. 2014-002491.

[0208] Among them, from the viewpoint of obtaining good optical and mechanical properties, preferred are styrene-acrylonitrile copolymers and rubber-containing graft copolymer particles having a graft portion on the surface layer, the graft portion being composed of a composition compatible with a methacrylic resin containing a structural unit having a ring structure.

[0209] The average particle size of the acrylic rubber particles, methacrylic rubber-containing graft copolymer particles, and rubbery polymer is preferably 0.03 to 1 μm, more preferably 0.05 to 0.5 μm, from the viewpoint of improving the impact strength and optical properties of the molded article obtained from the composition of this embodiment.

[0210] The content of the other thermoplastic resin is preferably 0 to 50 parts by mass, more preferably 0 to 25 parts by mass, based on 100 parts by mass of the methacrylic resin.

[0211] <<Second base material>>

[0212] The second substrate constituting the laminate of this embodiment can include any known transparent material without particular limitation. From the perspective of transparency and high refractive index, the second substrate preferably includes at least one selected from the group consisting of glass, cyclic polyolefin resins, polycarbonate resins, polyester resins, and methacrylic resins.

[0213] Examples of the glass that may be included in the second substrate include borosilicate-crown glass (BK7).

[0214] Cyclic polyolefin resins refer to resins containing cyclic olefins as polymerized units. Cyclic polyolefin resins that can be included in the second substrate are not limited, and examples include ring-opening (co)polymers of cyclic olefins and their hydrogenated products, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene, or aromatic compounds having a vinyl group, and modified (co)polymers obtained by modifying these with unsaturated carboxylic acids or their derivatives.

[0215] The polycarbonate resin is a resin comprising a portion (carbonate group) formed by connecting structural units of the resin via carbonate bonds. The polycarbonate resin that can be included in the second substrate is not limited, and examples thereof include polycarbonate resins derived from bisphenol A and polycarbonate resins having a fluorene skeleton. From the perspective of achieving a high refractive index and low birefringence, polycarbonate resins having a fluorene skeleton are preferred.

[0216] The polyester resin is a resin having an ester bond. The polyester resin that can be included in the second substrate is not limited, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexane dimethanol terephthalate, and polycyclohexane dimethanol naphthalate. From the perspective of achieving a high refractive index and low birefringence, the polyester resin is preferably one having a fluorene skeleton.

[0217] Examples of the methacrylic resin that may be contained in the second substrate include the same resins as those contained in the first substrate, and the description regarding the methacrylic resin contained in the first substrate can be cited.

[0218] The thickness of the second substrate is preferably 0.6 to 20 mm, more preferably 0.7 to 20 mm, and even more preferably 1.0 to 10 mm. If the thickness of the second substrate is within this range, the occurrence of poor appearance such as warping and peeling of the adhesive bond after the high-temperature humidity test can be suppressed. The thickness of the second substrate can be measured using the method described in the Examples below.

[0219] The thickness ratio of the thickest portion to the thinnest portion of the second substrate (thickness of the thickest portion / thickness of the thinnest portion) is preferably greater than 1.5 and less than 40, more preferably greater than 1.8 and less than 20, and even more preferably greater than 2.0 and less than 10. If the thickness ratio of the thickest portion to the thinnest portion of the second substrate (thickness of the thickest portion / thickness of the thinnest portion) is within the above range, peeling of the adhesive portion after the high temperature humidity test can be suppressed. The thickness of the second substrate can be measured by the method described in the Examples below.

[0220] The refractive index of the second substrate is preferably 1.50 to 1.70, more preferably 1.60 to 1.69, and even more preferably 1.63 to 1.68. If the refractive index of the second substrate is within the above range, there is a tendency to correct chromatic aberration when the laminate is used as an optical component. It should be noted that the refractive index of the second substrate can be measured by the method described in the Examples below.

[0221] <<Adhesive layer>>

[0222] The laminate of this embodiment includes an adhesive layer between a first substrate and a second substrate composed of a methacrylic resin. The size and shape of the adhesive layer are not particularly limited; however, from the perspective of achieving uniform in-plane thickness and sufficient adhesive strength, the average thickness is preferably 0.01 to 500 μm, more preferably 0.5 to 100 μm, and even more preferably 1.0 to 10 μm.

[0223] The adhesive layer can use known adhesives and tackifiers, but from the viewpoint of high bonding strength and heat resistance, it is preferred to use an adhesive. As the adhesive, adhesives such as acrylic resins, epoxy resins, and silicone resins can be mentioned, and as its curing system, light-curing type, heat-curing type, etc. can be mentioned. The curing system is preferably a light-curing type, wherein, ultraviolet curing type is more preferred. By setting it as a light-curing type, thermal damage will not be caused to the first base material and the second base material comprising methacrylic resin during manufacturing, and product characteristics can be well maintained. It should be noted that, from the viewpoint of good adhesion to the first base material and the first base material, it is preferred to use an adhesive of a light-curing type acrylic resin.

[0224] Examples of commercially available adhesives include PHOTOBOND 300 (manufactured by SUNRISE CORPORATION) and OG198-54 (manufactured by Epoxy Technology, Inc.).

[0225] Examples of the material of the adhesive include (meth)acrylic monomers, photopolymerization initiators, photosensitizers, and additives.

[0226] As (methyl) acrylic acid monomer, for example, can enumerate 2-hydroxyethyl (methyl) acrylate, 2-hydroxypropyl (methyl) acrylate, 4-hydroxybutyl (methyl) acrylate, 4-hydroxycyclohexyl (methyl) acrylate, 5-hydroxycyclooctyl (methyl) acrylate, 1,3-butylene glycol (methyl) acrylate, 1,4-butylene glycol (methyl) acrylate, 1,6-hexanediol (methyl) acrylate, 3-methylpentanediol (methyl) acrylate, dicyclopentenyl acrylate, isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, methacrylic acid (2-isocyanoethyl) ester, 1,1-bis (acryloyloxymethyl) ethyl isocyanate etc.They can be used alone, also can be used in combination with two or more.In order to improve the glass transition temperature of bonding layer, and improve the water resistance under high temperature and humidification environment, as (methyl) acrylic acid monomer, preferably use the monomeric unit with alicyclic skeleton.

[0227] Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and oxime ester compounds. Examples of the photosensitizer include amine compounds and quinone compounds.

[0228] Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone; anthracenes having a substituent such as anthracene and alkyl ether; phenothiazine; and rubrene.

[0229] Examples of additives that may be included in the adhesive include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, vinylpropyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane; and oligomers such as an esterification product of maleic anhydride adducts of isoprene polymers and 2-hydroxyethyl methacrylate.

[0230] The method for forming the adhesive layer is not particularly limited, and an example includes a method of applying an adhesive so as to cover the adhesive surface and then irradiating the adhesive with light to cure the adhesive.

[0231] As a method for applying the adhesive, any conventionally known method can be used without particular limitation. Specific examples include spraying, spin coating, wire bar coating, dip coating, air knife coating, roll coating, doctor blade coating, and inkjet coating.

[0232] The light source used for light irradiation when curing the adhesive includes, for example, ultra-high pressure mercury lamps, high pressure mercury lamps, carbon arc lamps, xenon arc lamps, metal halide lamps, and the like, which emit ultraviolet light. The irradiation energy when performing ultraviolet irradiation is preferably 100 to 8000 mJ / cm 2 .

[0233] <Silane coupling agent layer>

[0234] The laminate of this embodiment is characterized by including a silane coupling agent layer between the first substrate and the adhesive layer, and / or including a silane coupling agent layer between the second substrate and the adhesive layer. The laminate of this embodiment includes at least one silane coupling agent layer, thereby firmly bonding the substrate and the adhesive layer, thereby suppressing peeling of the adhesive portion in a high-temperature and humid environment.

[0235] The silane coupling agent layer can be formed by chemically evaporating the silane coupling agent onto the first substrate and / or the second substrate. For example, a vacuum plasma apparatus is used to supply water, oxygen, or the like into a reaction chamber to hydrophilize the surface of the first substrate or the second substrate, and then react with the silane coupling agent to form the silane coupling agent layer.

[0236] When a plurality of silane coupling agent layers are provided, all of them may be formed of the same material or may be formed of different materials.

[0237] Silane coupling agent is a compound having an organic functional group that reacts with organic matter and a hydrolyzable group (for example, alkoxy group, etc.) that reacts with inorganic matter in the molecule, and is used for the purpose of improving the interaction of two materials at the interface of organic material and inorganic material. On the other hand, when using silane coupling agent to improve the interfacial interaction between organic materials, it is necessary to react the hydrolyzable group of organic material and silane coupling agent, so the treatment conditions are mostly limited. For example, in Japanese Patent No. 4065962 Gazette and Japanese Patent No. 5733392 Gazette, the treatment examples of epoxy resin and cyclic olefin resin being treated with silane coupling agent are recorded, but including the process of heating the resin substrate with high temperature and the process of irradiating vacuum ultraviolet light with short wavelength, the scope of the resin that can be applied is limited. In particular, methacrylic resin composition usually has low heat resistance and decomposes under the action of ultraviolet light. Therefore, it is preferably implemented under mild conditions to treat methacrylic resin composition with silane coupling agent.

[0238] As the silane coupling agent forming the silane coupling agent layer, known silane coupling agents can be used, but alkoxysilanes having at least one alkoxy group are preferably used. The number of alkoxy groups is preferably 2 or 3 (i.e., dialkoxysilane or trialkoxysilane), with 3 alkoxy groups being particularly preferred. The number of carbon atoms in the alkoxy group is preferably 1 to 4, more preferably 1 to 3.

[0239] Specific examples of the silane coupling agent forming the silane coupling agent layer include 3-(trimethoxysilyl)propyl methacrylate, 3-[tris(trimethylsilyloxy)silyl]propyl methacrylate, 3-[diethoxy(methyl)silyl]propyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, (triethoxysilyl)methyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl acrylate, 3-(methoxydimethylsilyl)propyl acrylate, 3-(trimethoxysilyl)propyl acrylate, [dimethoxy(methyl)silyl]methyl methacrylate, vinyltrimethoxysilane, triethoxyvinylsilane, dimethylethoxyvinylsilane, allyltrimethoxysilane, allyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, and dimethoxymethylvinylsilane. , trimethoxy(7-octen-1-yl)silane, 3-aminopropyltriethoxysilane, trimethoxy[3-(phenylamino)propyl]silane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-(ethoxydimethylsilyl)propane-1-amine, [3-(6-aminohexylamino)propyl]trimethoxy Silane, 3-aminopropyldiethoxymethylsilane, 3-(methylamino)propyltriethoxysilane, 3-aminopropyltrimethoxysilane, trimethoxy[3-(methylamino)propyl]silane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyl(dimethoxy)methylsilane, triethoxy(3-glycidyloxypropyl)silane, diethoxy(3-glycidyloxypropyl)methylsilane, etc. These can be used alone or in combination of two or more. From the viewpoint of good reactivity with acrylic adhesives, it is preferred to use a silane coupling agent having a (meth)acryloyl group.

[0240] The formation method of the silane coupling agent layer of the present embodiment can be formed by a liquid phase method or a gas phase method known in the past. For example, the liquid phase method is a method for forming a silane coupling agent layer by contacting a substrate with an organic solution containing a silane coupling agent for a predetermined time. On the other hand, the gas phase method is a method for forming a silane coupling agent layer by contacting a substrate with a vapor containing a silane coupling agent for a predetermined time without using a solvent. For example, a vacuum plasma device can be used, and water, oxygen, etc. can be supplied to the reaction chamber to introduce hydrophilic functional groups into the substrate surface, and then reacted with the silane coupling agent to form a silane coupling agent layer. The gas phase method is different from the liquid phase method and does not use a solvent. Therefore, it is possible to suppress damage to the substrate caused by dissolution of the solvent. In addition, from the viewpoint of being able to reduce the amount of waste liquid and having little environmental load, it is preferred to form a silane coupling agent layer by a gas phase method.

[0241] The plasma treatment during formation of the silane coupling agent layer can be performed using conventionally known methods. For example, atmospheric pressure plasma treatment can be used, in which a voltage is applied between metal electrodes facing each other via a dielectric and a space to generate plasma, and the generated plasma is irradiated with a process gas such as oxygen or nitrogen, thereby irradiating the substrate with plasma. Alternatively, vacuum plasma treatment can be used, in which the substrate is placed between metal electrodes facing each other via a dielectric in a sealed chamber, and the substrate surface is directly exposed to the plasma for treatment.

[0242] Resins whose molecular chains are easily broken by plasma irradiation, such as methacrylic resin compositions, can be treated using remote plasma methods, such as atmospheric pressure plasma treatment, where a plasma-containing process gas is irradiated onto the substrate, thereby minimizing damage to the substrate. On the other hand, direct plasma methods, such as vacuum plasma treatment, where the substrate is directly exposed to the plasma, offer high treatment efficiency and can be performed in a sealed environment, thereby reducing the risk of impurities being introduced during treatment. Furthermore, since the substrate hydrophilization step and the steps leading to silane coupling agent layer formation can be performed continuously in a single reactor, it is preferable to use a vacuum plasma method to form the silane coupling agent layer.

[0243] The gas used in the plasma treatment is not particularly limited as long as it can introduce hydroxyl groups to the surface of the substrate being treated, and conventionally known gases such as nitrogen, argon, oxygen, and water vapor can be used.

[0244] For the discharge treatment during plasma treatment, the amount of electric power is preferably 60W·min to 1500W·min, more preferably 100W·min to 1000W·min, and even more preferably 120W·min to 800W·min. If the amount of electric power during the discharge treatment is 60W·min or more, the hydrophilization treatment of the substrate is fully carried out, and there is a tendency to efficiently form a silane coupling agent layer. As a result, there is a tendency for the durability of the adhesive layer of the laminate under a high temperature and humid environment to be good. On the other hand, if the amount of electric power during the discharge treatment is 1500W·min or less, the brittle layer formed near the surface due to deterioration of the first substrate due to the plasma treatment is reduced, and there is a tendency for the durability of the adhesive layer of the laminate under a high temperature and humid environment to be good. Therefore, it is preferred to implement the discharge treatment within the range of 60W·min to 1500W·min.

[0245] Various conditions for forming the silane coupling agent layer (for example, the pressure and gas flow rate during vacuum plasma treatment) may be appropriately set and are not particularly limited.

[0246] As a method for confirming the formation of the silane coupling agent layer, known methods such as water contact angle measurement before and after the formation of the silane coupling agent layer, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (TOF-SIMS), and infrared spectroscopy can be used. It should be noted that when confirming the presence of the silane coupling agent layer after forming the first adhesive layer or the second adhesive layer on the silane coupling agent layer, the bonding interface can be exposed by mechanical stripping such as grinding / etching, chemical stripping using a solvent, or physical stripping by degrading the adhesive by heating or cooling, thereby enabling surface analysis.

[0247] Optical components

[0248] The optical component of this embodiment is characterized by including the laminate of this embodiment. The optical component of this embodiment includes the laminate of this embodiment, thereby suppressing deterioration of optical performance caused by peeling of the adhesive in a high-temperature and humid environment, and can obtain clear images when used as an optical component.

[0249] The optical component of the present embodiment can be manufactured using a conventionally known method, for example, the method described in Japanese Patent Application Laid-Open No. 2021-071528 or Japanese Patent Application Laid-Open No. 2023-49421.

[0250] The optical component of this embodiment can be used as a display component such as a head-mounted display or a wearable display, or as an optical lens such as a camera lens.

[0251] Example

[0252] Hereinafter, specific examples and comparative examples will be given for description, but the present invention is not limited thereto.

[0253] [raw material]

[0254] The raw materials used in the following Examples and Comparative Examples are as follows.

[0255] [[Raw materials constituting methacrylic resin]]

[0256] Methyl methacrylate (MMA): manufactured by Asahi Kasei Co., Ltd.

[0257] N-Phenylmaleimide (PMI): manufactured by Nippon Shokubai Co., Ltd.

[0258] N-cyclohexylmaleimide (CMI): manufactured by Nippon Shokubai Co., Ltd.

[0259] Styrene: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0260] Methyl 2-(hydroxymethyl)acrylate (MHMA): manufactured by Combi-Blocks company.

[0261] [[Organic solvents]]

[0262] Meta-xylene (mXy): manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0263] Methyl isobutyrate: manufactured by Kanto Chemical Co., Ltd.

[0264] Toluene: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0265] [[Polymerization initiator]]

[0266] 1,1-Di(tert-butylperoxy)cyclohexane: manufactured by NOF Corporation.

[0267] Tert-Amylperoxy-2-ethylhexanoate: “Luperox 575” manufactured by Arkema Yoshitomi, Ltd.

[0268] Tert-Amyl peroxyisononanoate: manufactured by Arkema Gifomi Co., Ltd.

[0269] Chain transfer agent

[0270] n-Octylmercaptan: manufactured by Chevron Phillips Chemical Company.

[0271] n-Dodecylmercaptan: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0272] [[additive]]

[0273] Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]: antioxidant, “Irganox 1010” manufactured by BASF.

[0274] Tris(2,4-di-tert-butylphenyl)phosphite: phosphorus-based antioxidant, “Irgafos 168” manufactured by BASF.

[0275] RIKEMAL H-100: Mold release agent, manufactured by Riken Vitamin Co., Ltd.

[0276] Stearyl phosphate / distearyl phosphate mixture: manufactured by Sakai Chemical Industry Co., Ltd.

[0277] Monomethylamine: manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0278] The measurement and evaluation methods of various characteristics are described below.

[0279] (1) Measurement of glass transition temperature of methacrylic resin composition

[0280] The glass transition temperature of the methacrylic resin composition was measured in accordance with JIS-K7121. Specifically, the glass transition temperature of the methacrylic resin composition was measured as follows.

[0281] A differential scanning calorimeter (DSC8000, manufactured by PerkinElmer Japan Co., Ltd.) was used under a nitrogen flow rate of 25 mL / min. The temperature was raised from room temperature (23°C) to 200°C at a rate of 10°C / min (primary heating), maintained at 200°C for 5 minutes, and after the sample was completely melted, the temperature was lowered from 200°C to 40°C at a rate of 10°C / min, maintained at 40°C for 5 minutes, and further heated again under the above heating conditions (secondary heating). In the DSC curve drawn during this period, the intersection of the step-like change curve during the second heating and the straight line with the same distance from each baseline extension in the vertical axis direction (midpoint glass transition temperature) was measured as the glass transition temperature (Tg) (°C).

[0282] (2) Analysis of structural units in methacrylic resin

[0283] For the methacrylic resin composition, 1 H-NMR determination and 13 C-NMR measurement was used to identify each structural unit in the methacrylic resin and calculate its amount. 1 H-NMR determination and 13The measurement conditions of C-NMR measurement are as follows.

[0284] Measuring equipment: JNM-ECZ400S, manufactured by JEOL Ltd.

[0285] Determination solvent: CDCl3 or d6-DMSO.

[0286] Measurement temperature: 40℃.

[0287] (3) Measurement of photoelastic coefficient of methacrylic resin composition

[0288] A methacrylic resin composition was pressed into a film using a vacuum compression molding machine to prepare a sample for measurement. Specifically, the sample preparation conditions involved preheating the film at 260°C under reduced pressure (approximately 10 kPa) for 10 minutes using a vacuum compression molding machine (SFV-30, manufactured by Shinto Metal Industries, Ltd.). The methacrylic resin composition was then compressed at 260°C under approximately 10 MPa for 5 minutes. After the pressure was reduced and released, the film was transferred to a cooling compression molding machine for cooling and solidification. The resulting pressed film was aged for at least 24 hours in a constant temperature and humidity chamber maintained at 23°C and 60% humidity, and then a test piece (approximately 150 μm thick and 6 mm wide) was cut out for measurement.

[0289] The photoelastic coefficient C was measured using a birefringence measuring apparatus described in detail in Polymer Engineering and Science, 1999, 39, 2349-2357. R (Pa -1 ).

[0290] A film-like test piece was placed in a film stretching apparatus (manufactured by Imoto Seisakusho Co., Ltd.), also housed in a constant temperature and humidity chamber, with the gap between the chucks at 50 mm. The apparatus was then positioned so that the laser beam path of a birefringence measuring apparatus (RETS-100, manufactured by Otsuka Electronics Co., Ltd.) was centered on the film. The birefringence of the test piece was measured while applying tensile stress at a strain rate of 50% / min (gap: 50 mm, chuck travel speed: 5 mm / min).

[0291] The absolute value of birefringence (|Δn|) and tensile stress (σ R ), the slope of the straight line was obtained by least square approximation, and the photoelastic coefficient (C R )(Pa -1 ) The tensile stress used in the calculation is 2.5MPa≤σ R Data between ≤10MPa.

[0292] C R =|Δn| / σR

[0293] The absolute value of birefringence (|Δn|) is as shown below.

[0294] |Δn|=|nx-ny|

[0295] (nx: refractive index in the stretching direction, ny: refractive index in the direction perpendicular to the stretching direction within the plane)

[0296] (4) Determination of total light transmittance

[0297] Total light transmittance was measured using a turbidimeter COH7700 (manufactured by Nippon Denshoku Industries, Ltd.) in accordance with JIS K7361 using a molded article having a thickness of 3 mm. Pellets of the methacrylic resin composition were dried at 90°C for at least 12 hours, and then molded using an injection molding machine (SE180EV-A, manufactured by Sumitomo Heavy Industries, Ltd.) using a mold measuring 100 mm × 100 mm × 3 mm thick.

[0298] (5) Determination of melt viscosity

[0299] A double capillary rheometer (manufactured by NETZSCH (Rosand)) was used under the conditions of JIS-K7199 at a temperature of 270°C and a shear rate of 1000 sec. -1 The melt viscosity (Pa·sec) of the methacrylic resin composition was measured under the conditions of a capillary die diameter of 1 mm.

[0300] (6) Measurement of In-Plane Phase Difference of First Substrate

[0301] The first substrate was placed on a PA-300-L measuring table (manufactured by Photonic Lattice, Inc.) and the in-plane retardation distribution was measured at a wavelength of 520 nm. The average absolute value of the in-plane retardation (Re) in the measurement area was calculated and used as the measured in-plane retardation (nm).

[0302] As a range that hardly adversely affects the optical characteristics, the in-plane retardation is preferably 10 nm or less.

[0303] It should be noted that when the first substrate reflects light and the phase difference cannot be accurately measured, a low-viscosity liquid (contact liquid manufactured by Shimadzu Corporation) having a refractive index close to that of the methacrylic resin forming the first substrate and that does not penetrate the methacrylic resin is added to the culture dish, and the first substrate is immersed in it. The liquid surface is arranged so that there is no height difference between the substrate and the liquid and is flat. In this state, the in-plane phase difference distribution is measured at a wavelength of 520 nm.

[0304] (7) Evaluation of bonding strength before and after high temperature and humidity test

[0305] The laminates obtained in the examples and comparative examples (such as Figure 1 and Figure 2 The test pieces were exposed to a temperature of 60°C and a relative humidity of 90% for 1000 hours (as shown in the figure), and the adhesive strength before and after the test was evaluated. It should be noted that the test pieces were conditioned for at least 24 hours in an environment of 23°C and a relative humidity of 50% prior to the adhesive strength evaluation, and the adhesive strength (initial adhesive strength) was measured.

[0306] The bond strength before and after the high-temperature humidity test was evaluated by tensile testing using a low-load universal testing machine (Instron) at a measurement temperature of 23°C, a crosshead speed of 5 mm / min, and a chuck distance of 100 mm. Five measurements were performed, and the average of the maximum stresses generated until the test piece broke was used as the bond strength.

[0307] (8) Evaluation of bonding strength before and after high temperature test

[0308] The laminates obtained in the examples and comparative examples (such as Figure 1 and Figure 2 High-temperature testing was performed by exposing the test pieces to an 80°C environment for 1000 hours (as shown in the figure), and the bonding strength before and after the test was evaluated. It should be noted that the test pieces were conditioned in an environment at 23°C and 50% relative humidity for at least 24 hours before the bonding strength evaluation, and the bonding strength (initial bonding strength) was measured.

[0309] To evaluate the bond strength before and after the high-temperature test, a tensile test was performed using a low-load universal testing machine (Instron) at a measurement temperature of 23°C, a crosshead speed of 5 mm / min, and a chuck distance of 100 mm. Five measurements were performed, and the average of the maximum stresses generated until the test piece broke was used as the bond strength.

[0310] (9) Confirmation of the presence of peeling at the adhesive portion and measurement of the peeling area ratio

[0311] The laminates obtained in the examples and comparative examples (such as Figure 1 and Figure 2After exposure to a temperature of 60°C and a relative humidity of 90% for 1000 hours (high-temperature humidity test), the adhesive layer was observed at 100x magnification using a VHX-7000 digital microscope (Keyence Corporation, Japan) to confirm any delamination of the adhesive. In the event of delamination, the area of ​​the normally bonded portion or the delamination portion was measured. When capturing the observed image, the adhesive layer was focused, and the lighting method and shooting conditions were adjusted to ensure a clear image. Furthermore, when observing an object with depth extending to the adhesive layer, the image was captured while performing depth compositing.

[0312] The area of ​​the normally bonded portion or the peeled portion was measured from the captured image, and the peeled area ratio (%) was calculated. When measuring the area of ​​the normally bonded portion, the peeled area was calculated by subtracting the area of ​​the normally bonded portion from the area of ​​the entire adhesive layer.

[0313] (10) Thickness measurement of the first substrate and the second substrate

[0314] The locations where the thickness of the first substrate and the second substrate was the largest (thickest part) were measured using a digital caliper CD-15AX (manufactured by Mitutoyo Corporation) and the measured values ​​were obtained.

[0315] (11) Measurement of the thickness ratio of the first substrate and the second substrate

[0316] The maximum thickness (thickest part) and minimum thickness (thinnest part) of the first and second substrates were measured using a digital caliper CD-15AX (manufactured by Mitutoyo Corporation), and the thickness ratio was calculated using the following formula.

[0317] Thickness ratio = thickness of thickest part / thickness of thinnest part

[0318] (12) Refractive index measurement of the second substrate

[0319] The substrate's measurement surface was polished to a frosted surface of #600 or greater, and the refractive index was measured at a wavelength of 587.6 nm using a precision refractometer (Kalnew Precision Refractometer KPR3000, manufactured by Shimadzu Corporation). First, a contact liquid (manufactured by Shimadzu Corporation) was applied to the polished surface of the sample and placed on the V-block prism of the refractometer. The refractive index was measured at 23°C and 50% RH. The angle of contact between the sample and the V-block prism was 90 ± 1 degrees, and the contact liquid used was ± 0.01 of the substrate's refractive index.

[0320] (Preparation of methacrylic resin composition)

[0321] -Synthesis Example 1〔Methacrylic Resin Composition A〕-

[0322] 318.7 kg of methyl methacrylate (hereinafter sometimes referred to as MMA), 35.5 g of N-phenylmaleimide (hereinafter sometimes referred to as PMI), 63.7 kg of N-cyclohexylmaleimide (hereinafter sometimes referred to as CMI), 0.341 kg of n-octyl mercaptan as a chain transfer agent, and 225.1 kg of m-xylene (hereinafter sometimes referred to as mXy) ​​were weighed and added to a 1.25 m³ / min stirred flask equipped with a jacketed temperature control device and a stirring blade. 3 The mixture was placed in a reactor and stirred to obtain a mixed monomer solution.

[0323] Then, 116.9 kg of mXy was measured and added to tank 1 to prepare for solvent replenishment.

[0324] Furthermore, 104.5 kg of MMA and 85.5 kg of mXy were weighed and placed in tank 2, and stirred to obtain a supplementary MMA solution.

[0325] The internal liquid of the reactor was bubbled with nitrogen at a rate of 30 L / min for 1 hour, and nitrogen was bubbled into each of tanks 1 and 2 at a rate of 10 L / min for 30 minutes to remove dissolved oxygen.

[0326] Then, steam was blown into the jacket to raise the temperature of the solution in the reactor to 125°C. While stirring at 50 rpm, a polymerization initiator solution prepared by dissolving 0.457 kg of 1,1-di(tert-butylperoxy)cyclohexane in 2.67 kg of mXy was added at a rate of 1 kg / hour to start polymerization. It should be noted that during polymerization, the temperature of the solution in the reactor was controlled at 125±2°C by adjusting the temperature of the jacket. 30 minutes after the start of polymerization, the rate of addition of the polymerization initiator solution was reduced to 0.25 kg / hour, and mXy was added from tank 1 at 29.24 kg / hour for 3.5 hours.

[0327] Then, 4 hours after the start of polymerization, the addition rate of the polymerization initiator solution was increased to 0.75 kg / hour, and the replenishing MMA solution was added from tank 2 at 95 kg / hour for 2 hours.

[0328] Furthermore, 6 hours after the start of the polymerization, the addition rate of the polymerization initiator solution was reduced to 0.25 kg / hour, and the addition was stopped 7 hours after the start of the polymerization.

[0329] 8 hours after the start of polymerization, a polymerization solution containing a methacrylic resin was obtained, to which 0.261 kg of Irganox 1010 as an antioxidant, 0.784 kg of Irgafos 168, and 0.784 kg of RIKEMAL H-100 as a release agent were added.

[0330] The resulting polymer solution was then supplied to a concentrator consisting of a tubular heat exchanger and a vaporizer, preheated to 250°C, for devolatilization. The vaporizer was maintained at a vacuum level of 10 to 15 Torr. The resin flowing out of the vaporizer was discharged using a screw pump, extruded through a wire drawing die, water-cooled, and pelletized to obtain a methacrylic resin composition A having N-substituted maleimide structural units.

[0331] The obtained methacrylic resin composition A had a glass transition temperature (Tg) of 133° C. and a melt viscosity of 131 Pa·sec.

[0332] The composition of the methacrylic resin composition A determined by NMR was MMA unit: 81% by mass, PMI unit: 7% by mass, and CMI unit: 12% by mass.

[0333] -Synthesis Example 2〔Methacrylic Resin Composition B〕-

[0334] A monomer composition consisting of 60.000 mol% methyl methacrylate (MMA), 39.998 mol% styrene, and 0.002 mol% tert-amylperoxy-2-ethylhexanoate as a polymerization initiator was continuously supplied at 1 kg / h to a 10 L complete mixing tank equipped with spiral ribbon blades. Continuous polymerization was carried out at an average residence time of 2.5 hours and a polymerization temperature of 150°C. Liquid was continuously withdrawn from the bottom of the polymerization tank to maintain a constant liquid level and supplied to a concentrator consisting of a tubular heat exchanger and a vaporizer for devolatilization. The vaporizer was maintained at a vacuum level of 10 to 15 Torr. The resin flowing from the vaporizer was discharged using a screw pump, extruded from a wire drawing die, water-cooled, pelletized, and introduced into a desolventizer to obtain pelletized methyl methacrylate-styrene copolymer. The composition of the methyl methacrylate-styrene copolymer determined by NMR was 60% by mass of MMA units and 40% by mass of styrene units.

[0335] The copolymer was dissolved in methyl isobutyrate to prepare a 10% by mass methyl isobutyrate solution. 500 parts by mass of the 10% by mass methyl isobutyrate solution of the copolymer and 1 part by mass of 10% by mass Pd / C (manufactured by NECHEMCAT CORPORATION) as a hydrogenation catalyst were placed in a 1000 mL autoclave apparatus. The mixture was maintained at 200°C at a hydrogen pressure of 9 MPa for 15 hours to hydrogenate the aromatic double bonds in the styrene portion of the copolymer. The hydrogenation catalyst was removed with a filter, and 0.05 parts by mass of RIKEMAL H-100 was added to the copolymer solution and mixed. The mixture was then supplied to a concentrator consisting of a tubular heat exchanger and a vaporizer for devolatilization. The vacuum degree of the vaporizer was set to 10 to 15 Torr. The resin flowing out of the vaporizer was discharged with a gear pump, extruded from a wire drawing die, water-cooled, and pelletized to obtain a methacrylic resin composition B having a hydrogenation reaction rate of 96%.

[0336] The obtained methacrylic resin composition B had a glass transition temperature (Tg) of 118° C. and a melt viscosity of 67 Pa·sec.

[0337] -Synthesis Example 3〔Methacrylic Resin Composition C〕-

[0338] A raw material solution was prepared by adding 41.0 kg of methyl methacrylate (MMA), 10.0 kg of methyl 2-(hydroxymethyl)acrylate (MHMA), and 50.0 kg of toluene to a 200 L reactor equipped with a paddle-type stirring device, a temperature sensor, a cooling tube, and a nitrogen inlet. While nitrogen was flowing through the reaction mixture, the temperature of the solution was raised to 107°C while stirring.

[0339] Separately, an initiator supply solution was prepared by mixing 0.05 kg of 1,1-di(tert-butylperoxy)cyclohexane and 0.36 kg of toluene.

[0340] When the temperature of the raw material solution reaches 107°C, the supply of the initiator solution is started according to the procedures (1) to (6).

[0341] (1) 0.0~0.5 hours: supply speed 0.20kg / hour.

[0342] (2) 0.5 to 1.0 hours: supply rate 0.10 kg / hour.

[0343] (3) 1.0 to 2.0 hours: supply rate 0.08 kg / hour.

[0344] (4) 2.0 to 3.0 hours: supply rate 0.07 kg / hour.

[0345] (5) 3.0-4.0 hours: supply rate 0.028 kg / hour.

[0346] (6) 4.0 to 7.0 hours: supply rate 0.026 kg / hour.

[0347] After the initiator was supplied for a total of 7 hours, the reaction was allowed to proceed for a further 1 hour, and the polymerization reaction was completed in a total of 8 hours.

[0348] During the polymerization reaction, the internal temperature was controlled at 107±2° C. 51 g of a stearyl phosphate / distearyl phosphate mixture was added to the obtained polymer solution, and a cyclocondensation reaction was carried out under reflux (about 90-110° C.) for 5 hours.

[0349] The resulting polymer solution was subjected to a cyclocondensation reaction and devolatilization treatment using a 42 mm φ twin-screw devolatilization extruder equipped with four front vents and one rear vent at 140 rpm and a resin amount of 10 kg / hour, yielding a methacrylic resin composition C. The resulting methacrylic resin composition C had a glass transition temperature (Tg) of 129°C and a melt viscosity of 72 Pa·sec. The composition of the methacrylic resin composition C, as determined by NMR, was 82% by mass of MMA units, 17% by mass of lactone ring structural units, and 1% by mass of MHMA units.

[0350] -Synthesis Example 4〔Methacrylic Resin Composition D〕-

[0351] A 1.25m2 stirring device equipped with a paddle-shaped blade, a temperature sensor, a cooling pipe, and a nitrogen inlet pipe was installed. 3 550 kg of methyl methacrylate (MMA), 450 kg of m-xylene, and 0.18 g of n-octyl mercaptan were added to a reactor and dissolved to prepare a raw material solution. While nitrogen was introduced, the solution was stirred and heated to 125°C.

[0352] Separately, an initiator supply solution was prepared by mixing 0.23 kg of 1,1-di(tert-butylperoxy)cyclohexane and 1.82 kg of m-xylene.

[0353] When the temperature of the raw material solution reaches 127°C, the supply of the initiator solution is started according to the procedures (1) to (6).

[0354] (1) 0.0~0.5 hours: supply speed 1.00kg / hour.

[0355] (2) 0.5 to 1.0 hours: supply rate 0.50 kg / hour.

[0356] (3) 1.0-2.0 hours: supply rate 0.42 kg / hour.

[0357] (4) 2.0 to 3.0 hours: supply rate 0.35 kg / hour.

[0358] (5) 3.0-4.0 hours: supply rate 0.20 kg / hour.

[0359] (6) 4.0 to 7.0 hours: supply rate 0.13 kg / hour.

[0360] After the initiator was supplied for a total of 7 hours, the reaction was further continued for 1 hour, and the polymerization reaction was completed in a total of 8 hours.

[0361] The obtained polymer solution was devolatilized using a φ42 mm devolatilizing extruder equipped with four front vents and one rear vent at 140 rpm and a resin amount of 10 kg / hour to obtain resin pellets.

[0362] 5 parts by mass of monomethylamine (40% by mass monomethylamine aqueous solution) per 100 parts by mass of the obtained resin pellets were introduced via a side feeder into a twin-screw extruder equipped with a vent at a cylinder temperature of 250°C to carry out an imidization reaction. Excess methylamine and water were appropriately removed from a vent provided on the downstream side of the extruder to obtain a methacrylic resin composition D. The resulting methacrylic resin composition D had a glass transition temperature (Tg) of 122°C and a melt viscosity of 158 Pa·sec.

[0363] The composition of the methacrylic resin composition D determined by NMR was MMA unit: 95% by mass, and glutarimide-based structural unit: 5% by mass.

[0364] (Preparation of polycarbonate resin)

[0365] -Synthesis Example 5〔Polycarbonate Resin E〕-

[0366] 140.32 parts by weight of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 18.27 parts by weight of 2,2-bis(4-hydroxyphenyl)propane, 87.80 parts by weight of diphenyl carbonate, 5.0×10 -4The weight portion was placed in a reactor equipped with a stirrer and a distillation device. After nitrogen substitution three times, it was heated to 215°C under a nitrogen environment of 760 Torr and stirred for 20 minutes. After complete dissolution, the temperature was adjusted to 150 Torr over 15 minutes and maintained at 215°C and 150 Torr for 20 minutes to carry out an ester exchange reaction. The temperature was further increased to 240°C at a rate of 37.5°C / hr and maintained at 240°C and 150 Torr for 10 minutes. Then, the temperature was adjusted to 120 Torr over 10 minutes and maintained at 240°C and 120 Torr for 70 minutes. Then, the temperature was adjusted to 100 Torr over 10 minutes and maintained at 240°C and 100 Torr for 10 minutes. It was further reduced to below 1 Torr over 40 minutes and a polymerization reaction was carried out under stirring at 240°C and below 1 Torr for 10 minutes. After the reaction was completed, nitrogen was blown into the reactor to increase the pressure, and the generated resin was drawn out while being granulated to obtain a polycarbonate resin E.

[0367] (Preparation of polyester resin)

[0368] -Synthesis Example 6〔Polyester Resin F〕-

[0369] 119.81 parts by weight of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 78.03 parts by weight of dimethyl terephthalate, 15.96 parts by weight of ethylene glycol, 1.37×10 -4 Parts by weight of tetrabutoxytitanium were placed in a reactor equipped with a stirrer and a distillation apparatus. After nitrogen substitution three times, the reactor was heated to 220°C under a nitrogen atmosphere of 760 Torr and stirred for 20 minutes. After complete dissolution, methanol removal was performed at 220°C. After distillation was nearly complete, 11.4 μL of trimethyl phosphate and 1.23 mL of a 0.5% aqueous germanium oxide solution were added. The temperature was raised to 280°C over 60 minutes, while the vacuum level was increased over 150 minutes. Polymerization was carried out under stirring at below 0.1 Torr for 10 minutes. After the reaction was completed, nitrogen was blown into the reactor to increase pressure, and the resulting resin was granulated and withdrawn to obtain polyester resin F.

[0370] (Preparation of Cyclic Olefin Resin)

[0371] -Synthesis Example 7〔Cyclic Olefin Resin G〕-

[0372] First, VO(OC2H5)Cl2 was diluted with cyclohexane to prepare a vanadium catalyst with a vanadium concentration of 6.7 mmol / L-cyclohexane. 1.5 Cl 1.5 ), prepare an organoaluminum compound catalyst with an aluminum concentration of 107 mmol / L-hexane.

[0373] Then, using a stirred polymerizer (inner diameter 500 mm, reaction volume 100 L), ethylene and tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene copolymerization reaction. Here, ethylene is supplied to the polymerization vessel together with hydrogen. When carrying out the copolymerization reaction, the vanadium catalyst prepared by the above method is supplied to the polymerization vessel in an amount such that the concentration of the vanadium catalyst relative to the cyclohexane in the polymerization vessel used as the polymerization solvent is 0.6 mmol / L. In addition, sesquiethylaluminum chloride as an organic aluminum compound is supplied to the polymerization vessel in an amount such that Al / V=18.0. The polymerization temperature is set to 8°C and the polymerization pressure is set to 1.8 kg / cm 2 G, continuously carry out copolymerization reaction.

[0374] To the ethylene extracted from the polymerizer and the tetracyclic [4.4.0.1 2,5 .1 7,10 ]-3-dodecene copolymer solution, water and a 25% by mass sodium hydroxide aqueous solution as a pH regulator were added to stop the polymerization reaction. In addition, the catalyst residue present in the copolymer was removed from the copolymer solution (deashing). Irganox 1010 as a stabilizer was added to the deashed ethylene and tetracyclo[4.4.0.1]-3-dodecene copolymer solution in an amount of 0.4 parts by mass per 100 parts by mass of the copolymer. 2,5 .1 7,10 ]-3-dodecene copolymer cyclohexane solution (polymer concentration 7.7% by mass). Then, before entering the flash drying process, temporarily use an effective volume of 1.0m 3 Mix in a stirring tank for 1 hour.

[0375] The cyclohexane solution of the copolymer having a copolymer concentration of 5% by mass was supplied at a rate of 150 kg / h to a 20 kg / cm 2 The mixture was heated to 180°C in a double-tube heater (outer tube diameter 2B, inner tube diameter 3 / 4B, length 21m) containing water vapor of G.

[0376] Use as heat source 25kg / cm 2 A double-tube flash dryer (outer tube diameter 2B, inner tube diameter 3 / 4B, length 27m) with water vapor of 1000 liters and a flash hopper (volume 200L) were used to remove most of the unreacted monomers from the cyclohexane solution of the copolymer after the heating step and flash drying of ethylene and tetracyclic [4.4.0.1 2,5 .1 7,10]-3-dodecene random copolymer (cyclic olefin resin).

[0377] EXCEPARL PE-MS (manufactured by Kao Corporation), a fatty acid ester, was directly charged in a molten state heated at 100°C for 4 hours into a twin-screw kneading extruder with a vent in an amount of 2.1 parts by mass relative to 100 parts by mass of the cyclic olefin copolymer (A-1). The mixture was kneaded with the cyclic olefin resin charged from the resin charging section of the extruder, and pelletized using an underwater pelletizer installed at the extruder outlet. The obtained pellets were dried with hot air at a temperature of 100°C for 4 hours to obtain cyclic olefin resin G.

[0378] The Tg of the obtained cyclic olefin resin G was 129° C. The weight ratio of oxygen determined from the monomer composition ratio was 0 wt %.

[0379] -Synthesis Example 8〔Cyclic Olefin Resin H〕-

[0380] 76 parts of styrene and 4 parts of isoprene were sealed in a nitrogen-purged stainless steel pressure-resistant container and stirred to prepare a mixed monomer. Then, 320 parts of dehydrated cyclohexane, 4 parts of the mixed monomer and 0.1 parts of dibutyl ether were placed in a nitrogen-purged stainless steel autoclave equipped with an electromagnetic stirring device, and 0.18 parts of a hexane solution of n-butyl lithium (concentration 15%) were added while stirring at 50°C to start polymerization. After 0.5 hours from the start of the reaction (the polymerization conversion rate at this time was 96%), 76 parts of the mixed monomer were continuously added to the polymerization reaction solution over 1 hour to continue the polymerization reaction. After another 0.5 hours from the end of the addition (the polymerization conversion rate at this time was 95%), 0.1 parts of isopropyl alcohol were added to stop the polymerization reaction to obtain a styrene-isoprene copolymer.

[0381] Then, 8 parts of a stabilized nickel hydrogenation catalyst (60% nickel-loaded silica-alumina carrier) was added to 400 parts of the above-mentioned polymerization reaction solution, and the mixture was placed in a stainless steel autoclave. The interior of the autoclave was replaced with hydrogen, and hydrogen was supplied to maintain the pressure inside the autoclave at 4.5 MPa. The hydrogenation reaction was carried out at 160°C for 6 hours. Then, pressure filtration was performed at a pressure of 0.25 MPa using a pressure filter with diatomaceous earth (Radiolite #800) as a filter bed to obtain a colorless and transparent solution from which the catalyst had been removed. While stirring, the hydrogenation reaction solution was injected into a mixed solution of 250 parts of acetone and 250 parts of isopropanol to precipitate the hydride, which was filtered and recovered. After washing the recovered hydride with 200 parts of acetone, the cyclic olefin resin H was obtained after drying for 24 hours in a vacuum dryer at 100°C with the pressure reduced to less than 1 mmHg. The Tg of the obtained cyclic olefin resin H was 127°C.

[0382] (Example 1)

[0383] The methacrylic resin composition A was used as the material of the first substrate, and the cyclic olefin resin G was used as the material of the second substrate, to prepare the first substrate and the second substrate.

[0384] [Preparation Step of First and Second Substrates]

[0385] The first substrate and the second substrate were processed into a size of 100×25×3 mm, and the first substrate and the second substrate were ultrasonically cleaned with pure water for 5 minutes, air-dried, and then dried in an oven at 80°C for 1 hour.

[0386] [Silane Coupling Agent Layer Formation Step]

[0387] In the silane coupling agent layer forming step, the silane coupling agent layer is formed on the bonding surfaces of the first base material and the second base material.

[0388] The silane coupling agent layers on the first and second substrates were formed by plasma treatment using a capacitively coupled high-frequency plasma device. First, the pressure in the reaction chamber was reduced to 5-10 Pa using a pressure reducing mechanism. Water vapor was then introduced into the chamber to a pressure of 100 Pa. Plasma was generated by irradiating the chamber with water vapor for 3 minutes using a high frequency of 13.56 MHz and a power of 50 W. Vapor of 3-(trimethoxysilyl)propyl methacrylate was then introduced into the chamber to react with 3-(trimethoxysilyl)propyl methacrylate on the surfaces of the first and second substrates, thereby forming the silane coupling agent layers. The contact angles of water before and after the silane coupling agent layers were formed on the first and second substrates were measured using a contact angle meter DMs-401 (manufactured by Kyowa Interface Chemical Co., Ltd.). The results showed that the contact angles of water changed before and after the silane coupling agent layers were formed, confirming the formation of silane coupling agent layers on the substrate surfaces.

[0389] [Adhesive Layer Formation Step]

[0390] In the adhesive layer forming step, an adhesive layer is formed between the silane coupling agent layer of the first substrate and the second substrate.

[0391] First, PHOTOBOND 300 (manufactured by SUNRISECORPORATION., a light-curing acrylic adhesive) was applied to the silane coupling agent layer on the adhesive surface of the first substrate using a dispenser. Then, a built-in UV curing device HLR400 (manufactured by SEN LIGHTS Co., Ltd.) was used to cure the silane coupling agent layer at a light intensity of 3000 mJ / cm 2 UV irradiation was performed and the bonding area was 6.25 cm2 The bonding film thickness is 0.06 mm, and the Figure 1 and Figure 2 The stack shown.

[0392] (Example 2)

[0393] A laminate was produced under the same conditions as in Example 1, except that the reagent for forming the silane coupling agent layer was changed from 3-(trimethoxysilyl)propyl methacrylate to trimethoxy(7-octen-1-yl)silane. The evaluation results are shown in Table 1.

[0394] (Example 3)

[0395] A laminate was produced under the same conditions as in Example 1, except that the methacrylic resin composition B obtained in Synthesis Example 2 was used to produce the first substrate. The evaluation results are shown in Table 1.

[0396] (Example 4)

[0397] A laminate was produced under the same conditions as in Example 1, except that the methacrylic resin composition C obtained in Synthesis Example 3 was used to produce the first substrate. The evaluation results are shown in Table 1.

[0398] (Example 5)

[0399] A laminate was produced under the same conditions as in Example 1, except that the methacrylic resin composition D obtained in Synthesis Example 4 was used to produce the first substrate. The evaluation results are shown in Table 1.

[0400] (Example 6)

[0401] A laminate was produced under the same conditions as in Example 1, except that the adhesive was changed to Chemiseal U-1430 (manufactured by Chemitech Inc.). The evaluation results are shown in Table 1.

[0402] (Example 7)

[0403] A laminate was produced under the same conditions as in Example 1, except that borosilicate crown glass (BK7) was used as the material of the second substrate.

[0404] (Example 8)

[0405] A laminate was produced under the same conditions as in Example 1, except that the second substrate was produced using polycarbonate-based resin E as the material of the second substrate. The evaluation results are shown in Table 1.

[0406] (Example 9)

[0407] A laminate was produced under the same conditions as in Example 1, except that polyester resin F was used as the second substrate material and the second substrate was subjected to water vapor plasma irradiation without forming a silane coupling agent layer.

[0408] (Example 10)

[0409] Before forming the silane coupling agent layer, Acier E50PG manufactured by Nidek Co., Ltd. was sprayed on the bonding surface of the first substrate. After drying, the adhesive was irradiated with a high-pressure mercury lamp at a power of about 1000 mJ / cm 2 A laminate was produced under the same conditions as in Example 1 except that the ultraviolet rays of 100 μm were applied to form a hard coating layer having a thickness of about 3 μm. The evaluation results are shown in Table 1.

[0410] (Example 11)

[0411] The adhesive was changed to OG198-54 (Epoxy Technology, Inc., epoxy adhesive) and the light intensity was 3060 mJ / cm 2 A laminate was produced under the same conditions as in Example 1 except that UV irradiation and bonding were performed. The evaluation results are shown in Table 1.

[0412] (Example 12)

[0413] A laminate was produced under the same conditions as in Example 1, except that no silane coupling agent layer was formed between the first base material and the adhesive layer.

[0414] (Example 13)

[0415] Using methacrylic resin composition A as the first substrate and cyclic olefin resin G as the second substrate, a plano-convex lens with a thickness of 8.2 mm at its thickest portion and a thickness ratio of 2.7 at its thickest portion to its thinnest portion was produced. After preparing the first and second substrates, a silane coupling agent layer was formed on the flat surface of the lens using the same method as in Example 1, and the lenses were bonded together to produce a laminate. The evaluation results are shown in Table 2.

[0416] (Example 14)

[0417] A laminate was produced by the same method as in Example 13, except that the methacrylic resin composition A was used as the material of the first substrate and the cyclic olefin resin H was used as the material of the second substrate.

[0418] (Example 15)

[0419] The evaluation results are shown in Table 2, except that the methacrylic resin composition A was used as the material of the first substrate and borosilicate crown glass (BK7) was used as the material of the second substrate.

[0420] (Example 16)

[0421] A laminate was produced by the same method as in Example 13, except that the methacrylic resin composition A was used as the material of the first substrate and the polycarbonate resin E was used as the material of the second substrate.

[0422] (Example 17)

[0423] A laminate was produced by the same method as in Example 13, except that the methacrylic resin composition A was used as the material of the first substrate and the polyester resin F was used as the material of the second substrate.

[0424] (Example 18)

[0425] Using methacrylic resin composition A as the first substrate and cyclic olefin resin G as the second substrate, a rectangular prism was produced with a thickness of 3.2 mm at its thickest portion and a thickness ratio of 28 between the thickest portion and the thinnest portion. After preparing the first and second substrates, a silane coupling agent layer was formed on the inclined surface of the rectangular prism using the same method as in Example 1, and the layers were bonded together to produce a laminate. The evaluation results are shown in Table 2.

[0426] (Example 19)

[0427] A laminate was produced by the same method as in Example 18, except that the methacrylic resin composition A was used as the material of the first substrate and the polycarbonate resin E was used as the material of the second substrate.

[0428] (Example 20)

[0429] Using methacrylic resin composition A as the first substrate and cyclic olefin resin G as the second substrate, a rectangular prism was produced with a thickness of 20 mm at its thickest portion and a thickness ratio of 47 between the thickest portion and the thinnest portion. After preparing the first and second substrates, a silane coupling agent layer was formed on the inclined surface of the rectangular prism using the same method as in Example 1, and the layers were bonded together to produce a laminate. The evaluation results are shown in Table 2.

[0430] (Comparative Example 1)

[0431] A laminate was produced under the same conditions as in Example 1, except that the laminate was bonded without forming a silane coupling agent layer. The evaluation results are shown in Table 1.

[0432] (Comparative Example 2)

[0433] Without forming a silane coupling agent layer, the adhesive was changed to OG198-54 (manufactured by Epoxy Technology, Inc.) and the light intensity was 3060 mJ / cm 2 A laminate was produced under the same conditions as in Example 1 except that UV irradiation and bonding were performed. The evaluation results are shown in Table 1.

[0434] (Comparative Example 3)

[0435] A laminate was produced under the same conditions as in Example 7, except that the laminate was bonded without forming a silane coupling agent layer. The evaluation results are shown in Table 1.

[0436] (Comparative Example 4)

[0437] A laminate was produced under the same conditions as in Example 1, except that the thickness of the first substrate and the second substrate was changed to 0.5 mm. The evaluation results are shown in Table 1.

[0438] (Comparative Example 5)

[0439] A laminate was produced under the same conditions as in Example 19, except that the laminate was bonded to the second substrate without forming a silane coupling agent layer.

[0440] (Comparative Example 6)

[0441] A right-angle prism was produced using methacrylic resin composition A as the first substrate and cyclic olefin resin G as the second substrate. The thickest portion had a thickness of 27 mm and a thickness ratio of 59 between the thickest portion and the thinnest portion. After preparing the first and second substrates, a silane coupling agent layer was formed on the inclined surface of the right-angle prism using the same method as in Example 1, and the layers were bonded together to produce a laminate. The evaluation results are shown in Table 2.

[0442] (Comparative Example 7)

[0443] A cylindrical molded article having a thickness of 22 mm at its thickest portion was produced using methacrylic resin composition A as the first substrate and cyclic olefin resin G as the second substrate. After preparing the first and second substrates, a silane coupling agent layer was formed and bonded together using the same method as in Example 1 to produce a laminate. The evaluation results are shown in Table 2.

[0444]

[0445]

[0446] Tables 1 and 2 show that the laminates of Examples 1 to 20, which included a silane coupling agent layer between the substrate and the adhesive layer, suppressed peeling of the adhesive portion after high-temperature humidification. Furthermore, it was found that peeling of the adhesive portion was further suppressed when the adhesive layer contained a photocurable acrylic adhesive.

[0447] The laminate and optical component provided by the present invention suppress peeling of the adhesive in a high-temperature and humid environment and can therefore be suitably used as display components such as head-mounted displays and wearable displays, and optical lenses such as camera lenses.

Claims

1. A laminated body, wherein: The first substrate and the second substrate are bonded together at least via an adhesive layer. The thickness of the first substrate and the second substrate is 0.6 to 20 mm, The first substrate comprises a methacrylic resin composition, A silane coupling agent layer is included between the first substrate and the adhesive layer, and / or a silane coupling agent layer is included between the second substrate and the adhesive layer.

2. The laminate according to claim 1, wherein The methacrylic resin composition has a glass transition temperature (Tg) of 115°C to 160°C.

3. The laminate according to claim 1 or 2, wherein The absolute value of the photoelastic coefficient of the methacrylic resin composition is 10×10 -12 Pa -1 the following.

4. The laminate according to claim 1 or 2, wherein The methacrylic resin composition includes a methacrylic resin including a structural unit having a ring structure.

5. The laminate according to claim 4, wherein The structural unit having a ring structure includes at least one structural unit selected from the group consisting of a structural unit derived from an N-substituted maleimide monomer, a glutarimide-based structural unit, an aromatic vinyl structural unit, an alicyclic vinyl structural unit, and a lactone ring structural unit. The laminate according to claim 4 , wherein: The structural unit having a ring structure includes a structural unit derived from an N-substituted maleimide monomer.

7. The laminate according to claim 1 or 2, wherein The second substrate includes at least one selected from the group consisting of glass, cyclic polyolefin-based resins, polycarbonate-based resins, polyester-based resins, and methacrylic-based resins.

8. The laminate according to claim 1 or 2, wherein The adhesive layer includes a photocurable acrylic adhesive.

9. The laminate according to claim 1 or 2, wherein The thickness ratio of the thickest portion to the thinnest portion of each of the first substrate and the second substrate is greater than 1.5 and less than 40, where the thickness ratio is the thickness of the thickest portion / the thickness of the thinnest portion.

10. An optical component, wherein: The optical component includes the laminate according to claim 1 or 2.

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