LAMINATE AND METHOD FOR MANUFACTURING LAMINATE

Abstract

To provide a laminate with a colloidal crystal layer, which is superior in terms of the color developability, substrate followability, indentation resistance and scratch resistance, and to provide a manufacturing method therefor.SOLUTION: The above problem is cleared by a laminate comprising at least a base material layer and a light interference-based color developing layer comprising, in order from the base material side, a first colloidal crystal layer containing core shell-type fine resin particles, a resin layer having a glass transition temperature in a range of -30 to 50°C, and a second colloidal crystal layer containing core shell-type fine resin particles.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a laminate having a colloidal crystal layer, and more particularly to a laminate having a colloidal crystal layer that is excellent in color development, substrate conformability, indentation resistance, and scratch resistance. [Background technology]

[0002] Photonic crystals are nano-periodic structures in which materials with different refractive indices are arranged at intervals equivalent to the wavelength of light. Photonic crystals are currently the subject of active research because the refractive index changes periodically within them, resulting in a variety of interesting optical properties, such as the reflection of light of a specific wavelength known as Bragg reflection, light trapping using photonic bandgaps, and high demultiplexing properties. Colloidal crystals, one type of photonic crystal, have a structure in which submicron-order polymer latex particles or silica particles are regularly arranged, and are relatively easy to fabricate. However, mass production technology has not yet been established due to issues such as particle arrangement and fixation. In this situation, for example, Patent Documents 1 and 2 disclose that colloidal crystals composed of core-shell type resin microparticles having a shell with a low glass transition point and a core with a high glass transition point have relatively good color development and are stably fixed. However, the colloidal crystal coating films described in these patent documents all consist of a single colloidal crystal layer, and such a single-layer structure makes it difficult to satisfy the practical requirements in terms of color development. Furthermore, when a second colloidal crystal layer is formed directly on a first colloidal crystal layer in order to improve color development, the uneven structure originating from the first colloidal crystal layer prevents the formation of an ordered array in the second colloidal crystal layer, causing the colloidal crystal coating film to whiten and worsening color development. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-026551 A [Patent Document 2] JP 2008-083545 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a laminate having a colloidal crystal layer, which is excellent in color development, conformability to a substrate, resistance to indentation, and resistance to scratching, and a method for producing the laminate. [Means for solving the problem]

[0005] That is, the present invention relates to a laminate comprising at least a base layer and a layer that develops color due to light interference, the layer that develops color due to light interference comprising, from the base layer side, a first colloidal crystal layer containing core-shell resin microparticles, a resin layer having a glass transition point of −30 to 50° C., and a second colloidal crystal layer containing core-shell resin microparticles, in this order.

[0006] The present invention also relates to the above laminate, wherein the core-shell type resin fine particles have an average particle size of 180 to 330 nm.

[0007] The present invention also relates to the above laminate, wherein the core-shell type resin fine particles have a shell in an amount of 10 to 300% by mass based on the mass of the core.

[0008] The present invention also relates to the above laminate, wherein the core-shell type resin fine particles have a shell of 10 to 50% by mass based on the mass of the core, the core has a glass transition point of 60°C or higher, and the shell has a glass transition point of -50 to 20°C.

[0009] The present invention also relates to the above laminate, wherein the core-shell type resin fine particles are polymerized using a reactive surfactant.

[0010] The present invention also relates to the above laminate, wherein the resin forming the resin layer has a weight average molecular weight of 50,000 or more.

[0011] The present invention also relates to the above laminate, wherein the acid value of the resin forming the resin layer is 5 to 70 mgKOH / g.

[0012] The present invention also relates to the above laminate, wherein the resin layer has a thickness of 1.0 to 20 μm.

[0013] The present invention also relates to a method for producing a laminate including at least a base layer and a layer that develops color through the interference of light, the method comprising the following steps 1 to 3 in this order: Step 1) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto a base layer to form a first colloidal crystal layer. Step 2) A step of applying a composition for a resin layer, which contains fine resin particles having a glass transition point of −30 to 50° C., onto the first colloidal crystal layer to form a resin layer. Step 3) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto the resin layer to form a second colloidal crystal layer. Effect of the Invention

[0014] According to the present invention, it is possible to provide a laminate having a colloidal crystal layer, which is excellent in color development, conformability to a substrate, resistance to indentation, and resistance to scratching, and a method for producing the laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Laminate> The laminate of the present invention comprises at least a base layer and a layer that develops color due to optical interference, and is characterized in that the layer that develops color due to optical interference has, from the base layer side, a first colloidal crystal layer containing core-shell resin microparticles, a resin layer having a glass transition point of -30 to 50°C, and a second colloidal crystal layer containing core-shell resin microparticles, in this order. When the layer that develops color due to light interference is configured with two colloidal crystal layers arranged with a resin layer having a specific glass transition point interposed therebetween, the structural color development is better than that of a colloidal crystal coating film consisting of a single colloidal crystal layer or a laminate formed by directly overlapping a second colloidal crystal layer on a first colloidal crystal layer. This is because the interposition of the resin layer can prevent the regular arrangement of the second colloidal crystal layer from being disturbed. Therefore, while ensuring a thickness of the colloidal crystal layer that exhibits excellent color development, the regular arrangement is not disturbed, preventing the laminate from whitening and maintaining good color development. Furthermore, the colloidal crystal layer of the present invention has a regularly arranged structure made up of core-shell type resin microparticles, and during the formation of colloidal crystals, the shells of adjacent core-shell type resin microparticles, the shells of the core-shell type resin microparticles and the resin layer, and the shells of the core-shell type resin microparticles and the substrate are easily bound together, thereby exhibiting good substrate conformability, indentation resistance, and scratch resistance. Hereinafter, an embodiment of the present invention will be described in detail.

[0016] <Layer that develops color through light interference> The layer in the present invention that develops color due to optical interference comprises, in this order, a first colloidal crystal layer containing core-shell resin particles, a resin layer having a glass transition point of -30 to 50°C, and a second colloidal crystal layer containing core-shell resin particles, and the first and second colloidal crystal layers that exhibit structural colors derived from Bragg reflection are responsible for the color-developing function.

[0017] [First and second colloidal crystal layers] The first and second colloidal crystal layers each contain core-shell type resin particles. The core-shell type resin particles contained in the first colloidal crystal layer and the core-shell type resin particles contained in the second colloidal crystal layer may be the same or different. Furthermore, the core-shell type resin particles may be used alone or in combination of two or more types.

[0018] (Core-shell type resin particles) The core-shell type resin microparticles have a structure in which the core and shell are water-insoluble polymers and the core (inner layer) and shell (outer layer) are incompatible with each other. The core maintains a spherical shape, while the shell has fluidity and functions as a binding site. When a composition containing the core-shell type resin microparticles is applied to a substrate or the like, the particles are advected and accumulated to be regularly arranged as the medium such as water evaporates, forming a colloidal crystal layer. The shells of adjacent core-shell type resin microparticles, the shells of the core-shell type resin microparticles and the resin layer, and the shells of the core-shell type resin microparticles and the substrate can be easily bound to each other. The core-shell type resin fine particles in the present invention are not particularly limited, but are preferably polymers of ethylenically unsaturated monomers, and more preferably acrylic resins or styrene-acrylic resins.

[0019] {Ethylenically unsaturated monomer} Examples of the ethylenically unsaturated monomer include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, phenyl aromatic ethylenically unsaturated monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate ethylenically unsaturated monomers containing a straight or branched alkyl group, such as ... ethylenically unsaturated monomers containing an alicyclic alkyl group, such as trifluoroethyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and the like; ethylenically unsaturated monomers containing a fluorinated alkyl group, such as trifluoroethyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and the like; ethylenically unsaturated monomers containing a carboxy group, such as (anhydrous) maleic acid, fumaric acid, itaconic acid, citraconic acid, or their alkyl or alkenyl monoesters, succinic acid β-(meth)acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and the like;Sulfo group-containing ethylenically unsaturated monomers such as 2-acrylamido 2-methylpropanesulfonate sodium, methallylsulfonic acid, methallylsulfonic acid, sodium methallylsulfonate, allylsulfonic acid, sodium allylsulfonate, ammonium allylsulfonate, and vinylsulfonic acid; (meth)acrylamide, N-methoxymethyl-(meth)acrylamide, N-ethoxymethyl-(meth)acrylamide, N-propoxymethyl-(meth)acrylamide, N-butoxymethyl-(meth)acrylamide, N-pentoxymethyl-(meth)acrylamide, N,N-di(methoxymethyl)acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N,N-di(ethoxymethyl)acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide, N,N-di(propoxymethyl)acrylamide, N-butoxymethyl-N-(propoxymethyl)methacrylamide, N,N-di(butoxymethyl)acrylamide, ethylenically unsaturated monomers containing an amide group, such as N-butyl-N-(methoxymethyl)acrylamide, N,N-di(pentoxymethyl)acrylamide, N-methoxymethyl-N-(pentoxymethyl)methacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, and diacetone acrylamide; ethylenically unsaturated monomers containing a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, and allyl alcohol; ethylenically unsaturated monomers containing a polyoxyethylene group, such as methoxypolyethylene glycol (meth)acrylate and polyethylene glycol (meth)acrylate;Examples of the ethylenically unsaturated monomer include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methylethylaminoethyl (meth)acrylate, dimethylaminostyrene, and diethylaminostyrene. Examples of the ethylenically unsaturated monomer include amino group-containing ethylenically unsaturated monomers such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and methylethylaminoethyl (meth)acrylate; and epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth)acrylate and 3,4-epoxycyclohexyl (meth)acrylate. ethylenically unsaturated monomers containing a ketone group, such as diacetone (meth)acrylamide and acetoacetoxy (meth)acrylate; allyl (meth)acrylate, 1-methylallyl (meth)acrylate, 2-methylallyl (meth)acrylate, 1-butenyl (meth)acrylate, 2-butenyl (meth)acrylate, 3-butenyl (meth)acrylate, 1,3-methyl-3-butenyl (meth)acrylate, 2-chloroallyl (meth)acrylate, 3-chloroallyl (meth)acrylate, o-allylphenyl (meth)acrylate acrylate, 2-(allyloxy)ethyl (meth)acrylate, allyl lactyl (meth)acrylate, citronellyl (meth)acrylate, geranyl (meth)acrylate, rosinyl (meth)acrylate, cinnamyl (meth)acrylate, diallyl maleate, diaryl itaconic acid, vinyl (meth)acrylate, vinyl crotonate, vinyl oleate, vinyl linoleate, 2-(2'-vinyloxyethoxy)ethyl (meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol (meth)acrylate ethylenically unsaturated monomers having two or more ethylenically unsaturated groups, such as ethylenically unsaturated acrylate, tetraethylene glycol (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylpropane triacrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, and diallyl maleate;Examples of the ethylenically unsaturated monomers include alkoxysilyl groups such as γ-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltributoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxymethyltrimethoxysilane, 3-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinylmethyldimethoxysilane; and ethylenically unsaturated monomers containing methylol groups such as N-methylol(meth)acrylamide, N,N-dimethylol(meth)acrylamide, and alkyl etherified N-methylol(meth)acrylamide. These monomers may be used alone or in combination of two or more.

[0020] The ethylenically unsaturated monomer may also have a reactive group for the purpose of forming crosslinks within the colloidal crystal layer and between the colloidal crystal layer and the resin layer. By forming crosslinks within the colloidal crystal layer and between the colloidal crystal layer and the resin layer, the conformability to the substrate, indentation resistance, and scratch resistance of the laminate are improved. Crosslinking within the colloidal crystal layer and between the colloidal crystals and the resin layer can be introduced by a method of reacting reactive groups of core-shell type resin microparticles with each other, a method of reacting reactive groups of core-shell type resin microparticles with reactive groups in a resin layer described below, a method of crosslinking reactive groups of core-shell type resin microparticles with each other via a polyfunctional crosslinking agent, or a method of crosslinking reactive groups of core-shell type resin microparticles with reactive groups in a resin layer.

[0021] Examples of reactive groups that the ethylenically unsaturated monomer may have include epoxy groups, carboxy groups, hydroxyl groups, ketone groups, and hydrazide groups, and more preferably ketone groups. In particular, when the reactive group is a ketone group and the crosslinking agent is a hydrazide crosslinking agent, a ketone-hydrazide crosslink can be formed. Ketone-hydrazide crosslinking is preferably used because it does not adversely affect the physical properties of colloidal crystals and can form crosslinks at low temperatures and in a short time by volatilization of a medium such as water, and is effective when using a film substrate that is easily damaged by heating. In addition, since ketone groups are highly hydrophilic, when an ethylenically unsaturated monomer having a ketone group is used in a copolymerization composition, it is considered that the ketone group is introduced to the outside of the core-shell type resin microparticle, i.e., near the interface with the medium, and can efficiently form crosslinks with the hydrazide crosslinking agent.

[0022] When the core-shell type resin microparticles have a ketone group, the preferred content of the ketone group is in the range of 0.05 to 0.3 mmol / g based on the mass of the core-shell type resin microparticles. By introducing the ketone group in the range of 0.05 to 0.3 mmol / g, crosslinking is formed without inhibiting the fusion of the shell, so that the substrate conformability, indentation resistance, and scratch resistance of the laminate are further improved. In addition, when the content is within 0.3 mmol / g, the polymerization stability of the core-shell type resin microparticles is improved and the uniformity of the particle size is improved, so that the color development of the laminate is good.

[0023] The method for producing core-shell type resin microparticles is not particularly limited, and includes a method of polymerizing ethylenically unsaturated monomer in an aqueous medium such as emulsion polymerization, and a phase inversion emulsification method in which polymerization is performed in a non-aqueous system and then the phase is inverted to an aqueous phase while removing the solvent, but it is preferable to use emulsion polymerization because it can achieve high molecular weight, low viscosity, and high solid content concentration.In addition, in emulsion polymerization, either two-stage polymerization in which the monomer composition is changed between the first stage and the second stage and dropped, or multi-stage polymerization in which the monomer composition is changed in three or more stages and dropped, may be used. The core-shell type resin fine particles can be prepared by the above-mentioned two-stage polymerization, specifically, by the procedure shown below. (1) First, an aqueous medium and a surfactant are charged into a reaction tank and the temperature is raised. Then, under a nitrogen atmosphere, a radical polymerization initiator is added while an emulsion of an ethylenically unsaturated monomer in the first step of forming the core is dropped. After the reaction starts, the particles gradually grow according to the amount of the drop to form the core particle. (2) Next, when the first stage of dropping is completed and the heat generation has subsided, the second stage of dropping the emulsion of the ethylenically unsaturated monomer that forms the shell is started. At this time, additional initiator may be added. The dropped second stage ethylenically unsaturated monomer is once distributed to the core particles, but as the polymerization proceeds, it precipitates as a polymer on the outer layer of the core particles to form a shell layer.

[0024] {Radical polymerization initiator} As the radical polymerization initiator used in the production of core-shell type resin microparticles, a known oil-soluble polymerization initiator or water-soluble polymerization initiator can be used, and these may be used alone or in combination of two or more types.

[0025] The oil-soluble polymerization initiator is not particularly limited, and examples thereof include organic peroxides such as benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy(2-ethylhexanoate), tert-butylperoxy-3,5,5-trimethylhexanoate, and di-tert-butyl peroxide; and azobis compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 1,1'-azobis-cyclohexane-1-carbonitrile.

[0026] In the emulsion polymerization, it is preferable to use a water-soluble polymerization initiator. As the water-soluble polymerization initiator, for example, conventionally known ones such as ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride can be suitably used.

[0027] {Surfactant} In general, a surfactant is used in the production of core-shell type resin microparticles, and the use of the surfactant can improve the stability and monodispersity of the core-shell type resin microparticles. The surfactant may be anionic or nonionic, and preferably anionic surfactant. These may be used alone or in combination of two or more.

[0028] Examples of the surfactant include anionic reactive surfactants, anionic non-reactive surfactants, nonionic reactive surfactants, and nonionic non-reactive surfactants. Here, the reactive surfactant refers to a surfactant that can be polymerized with the above-mentioned ethylenically unsaturated monomer. More specifically, it means a surfactant having a reactive group that can polymerize with an ethylenically unsaturated bond. Examples of the reactive group include alkenyl groups such as vinyl groups, allyl groups, and 1-propenyl groups, and (meth)acryloyl groups. By using a reactive surfactant, the amount of free surfactant components contained in the core-shell type resin particles is reduced, and adverse effects on the particle arrangement of colloidal crystals are suppressed, so that the color development of the laminate is further improved, which is preferable.

[0029] {Other ingredients} In the production of the core-shell type resin particles, a reducing agent, a buffering agent, a chain transfer agent, and a neutralizing agent can be used as necessary.

[0030] {Characteristics of core-shell type resin particles} The average particle diameter of the core-shell type resin microparticles is preferably 180 to 330 nm. When the average particle diameter is 180 nm or more, the coloring property of the colloidal crystal in the visible light region is better, which is preferable. When the average particle diameter is 330 nm or less, the coloring property of the colloidal crystal in the visible light region is excellent, and scattering by the particles is suppressed, resulting in further improved coloring. The average particle size can be measured by dynamic light scattering (measuring device manufactured by Nanotrac UPA Co., Ltd., Microtrack Bell), and the peak of the obtained volume particle size distribution data (histogram) is regarded as the average particle size.

[0031] The coefficient of variation (Cv value) of the average particle size of the core-shell type resin fine particles is preferably 30% or less. The coefficient of variation is a value that indicates the uniformity of the particle size, and can be calculated by the following formula. Formula: Coefficient of variation Cv value (%) = standard deviation of particle size / average particle size x 100 [In the formula, the units of standard deviation and average particle size are the same] If the coefficient of variation is 30% or less, the regularity of the particle arrangement is improved, and the color development of the colloidal crystal is improved.

[0032] The glass transition point (Tg) of the core of the core-shell type resin microparticle is preferably 60° C. or higher, and more preferably in the range of 60° C. to 250° C. When the glass transition point is in the above range, excessive fusion of the core due to heat is prevented, and the refractive index difference between the particles and the gaps between the particles is maintained. Therefore, the color development of the colloidal crystal is further improved. The glass transition point of the shell of the core-shell type resin microparticles is preferably in the range of -50 to 20°C, more preferably in the range of -30 to 20°C. If the shell is -50°C or higher, the shell is prevented from flowing excessively due to heat during drying of the coating film, and the gaps between the particles are less likely to be filled with the shell. Therefore, the color development of the laminate is improved by the presence of sufficient gaps and the infiltration of air into the gaps. On the other hand, if the glass transition point of the shell is 20°C or lower, the fusion of the shell is sufficiently promoted, and the bonding between the core-shell type resin microparticles, between the core-shell type resin microparticles and the resin layer, and between the core-shell type resin microparticles and the substrate is strengthened, which is preferable because it improves the substrate followability, indentation resistance, and scratch resistance of the laminate. The glass transition point in this specification is a value determined using a DSC (differential scanning calorimeter).

[0033] In the core-shell type resin microparticles, the content of the shell is preferably in the range of 10 to 300% by mass, more preferably 10 to 150% by mass, based on the total mass of the core. When the content of the shell is 10% by mass or more, the fusion of the shell proceeds sufficiently when the coating is dried, and the bonding between the core-shell microparticles and between the core-shell particles and the substrate becomes stronger, so that a laminate having excellent substrate conformability, indentation resistance, and scratch resistance can be obtained, which is preferable. From the viewpoint of color development, the shell content is preferably 150% by mass or less, more preferably 50% by mass or less. A shell content of 150% by mass or less is preferable because it prevents the shell from being excessively fused by heat or a solvent, and sufficient voids are obtained. In the colloidal crystal layer, if air is present in the voids of the core-shell type resin fine particles, the difference in refractive index between the particles and the matrix becomes large, improving the color development of the colloidal crystal. On the other hand, from the viewpoint of scratch resistance, the shell content is preferably in the range of 50 to 300% by mass, more preferably in the range of 50 to 200% by mass. When the shell content is 50% by mass or more, the fusion of the shells is further promoted when the coating film is dried, and the bonds between the core-shell type resin particles and between the core-shell type resin particles and the substrate are stronger, so that a laminate having excellent scratch resistance can be obtained.

[0034] (Formation of First and Second Colloidal Crystal Layers) The first and second colloidal crystal layers may be formed by any method as long as they contain the above-mentioned core-shell type resin fine particles. For example, they can be formed by applying a composition for colloidal crystal layers, which contains core-shell type resin fine particles and water, onto the base layer or the resin layer. The colloidal crystal layer composition may contain colorants, nonionic surfactants, crosslinking agents, and the like for the purpose of improving coatability, coating resistance, and color development, as long as they do not adversely affect the particle arrangement or the various physical properties of the laminate.

[0035] {Coloring agent} As the colorant, for example, a black dye or pigment can be used. Carbon black is preferred from the viewpoint of having little effect on the reflection spectrum shape in the visible region, and a water dispersion of carbon black may also be used.

[0036] {Nonionic surfactant} When the colloidal crystal layer composition contains a nonionic surfactant, printability is improved without adversely affecting the formation of the colloidal crystal layer, and the color development of the resulting laminate is improved. The HLB value of the nonionic surfactant is preferably 10.0 to 19.0. By using a nonionic surfactant having such an HLB value, the leveling property of the composition for the colloidal crystal layer is improved, and the color development of the laminate is improved. The HLB value is a numerical representation of the hydrophilicity and lipophilicity of a material, and the smaller the HLB value, the higher the lipophilicity. In this specification, the HLB value is calculated by the Griffin method shown in the following formula (1). Formula (1): HLB value = 20 × (sum of formula weights of hydrophilic parts) ÷ (molecular weight of material)

[0037] {Crosslinking Agent} The colloidal crystal layer composition contains a crosslinking agent, which can form crosslinks between the core-shell type resin particles and between the core-shell type resin particles and the resin layer, thereby improving the film resistance. The crosslinking agent that may be added is not particularly limited, and examples thereof include hydrazide compounds (polyhydrazides) having two or more hydrazino groups that react with active carbonyl groups to form keto-hydrazide crosslinks, isocyanate compounds that react with hydroxyl groups or amino groups to form urethane bonds or urea bonds, and epoxy compounds that react with carboxy groups or amino groups, etc., and can be appropriately selected depending on the application. More specifically, when the core-shell type resin particles have a carboxyl group, they can be crosslinked via an epoxy crosslinking agent. Also, for example, when the core-shell type resin particles have a hydroxyl group, they can be crosslinked via a polyisocyanate crosslinking agent. Also, for example, when the core-shell type resin particles have a ketone group, they can be crosslinked via a hydrazide crosslinking agent. As the crosslinking agent, it is preferable to use a hydrazide crosslinking agent to form a ketone-hydrazide crosslink as described above. Examples of the hydrazide crosslinking agent include adipic acid dihydrazide and a water-soluble resin modified with a polyfunctional hydrazide group.

[0038] [Resin layer] The resin layer in the present invention is provided between the first colloidal crystal layer and the second colloidal crystal layer, and maintains the regular arrangement of the second colloidal crystal layer, preventing the layer that develops color due to light interference from whitening.

[0039] (resin) It is important that the glass transition point of the resin layer is -30 to 50°C, and preferably -20 to 30°C. If the glass transition point is -30°C or higher, the resin forming the resin layer is prevented from penetrating into the voids of the colloidal crystal layer, and the laminate exhibits excellent color development. If the glass transition point is 50°C or lower, the resin has excellent film-forming properties, and a smooth resin layer can be formed, so that the ordered arrangement of the second colloidal crystal layer is not disturbed, and whitening of the laminate is suppressed. Furthermore, since the resin layer has excellent binding properties with the first and second colloidal crystal layers, the obtained laminate can exhibit excellent substrate conformability, indentation resistance, and scratch resistance. The glass transition point of the resin layer is the glass transition point of the resin forming the resin layer, and the resin forming the resin layer may be one type alone or two or more types in combination.

[0040] The resin forming the resin layer is not particularly limited, and is preferably a polymer of an ethylenically unsaturated monomer, more preferably an acrylic resin or a styrene-acrylic resin. The ethylenically unsaturated monomer that can be used to produce the polymer includes the ethylenically unsaturated monomers exemplified in the section on the core-shell type resin particles described above. Furthermore, the above-mentioned ethylenically unsaturated monomer may have a reactive group for the purpose of forming crosslinks within the resin layer and between the colloidal crystal layer and the resin layer, and as the reactive group, the reactive groups exemplified in the section on the core-shell type resin fine particles described above can be used.

[0041] The resin is provided between the first colloidal crystal layer containing the core-shell microparticles and the second colloidal crystal layer, and from the viewpoint of preventing the resin from penetrating into the voids in the colloidal crystal layer and impairing color development, it is preferably applied in the form of resin microparticles and forms a film and a resin layer during the drying process. The method for producing such resin microparticles is not particularly limited and can be appropriately selected from known methods. However, it is preferable that the resin be polymerized using emulsion polymerization, since it has a high molecular weight, low viscosity, and can have a high solid content.

[0042] The average particle diameter of the resin fine particles is preferably 60 to 300 nm. When the average particle diameter is 60 nm or more, the resin forming the resin layer remains at the interface with the colloidal crystal layer, so that the aqueous resin does not penetrate more than necessary into the voids of the colloidal crystals and does not adversely affect color development. When the average particle diameter is 300 nm or less, the resin has sufficient film-forming properties to form a smooth resin layer, so that the orderly arrangement of the second colloidal crystal layer provided on the resin layer is prevented from being disturbed, whitening is suppressed, and the color development of the laminate is improved.

[0043] The weight-average molecular weight of the resin forming the resin layer is preferably 50,000 or more, more preferably 100,000 or more. If the weight-average molecular weight is 50,000 or more, the resin forming the resin layer is prevented from penetrating into the voids of the colloidal crystal layer, and the color development of the laminate is more excellent. Furthermore, the strength of the resin layer and the binding force to the colloidal crystal layer are improved, so that the laminate has good substrate conformability, indentation resistance, and scratch resistance. Moreover, the weight-average molecular weight of the resin is usually 15,000,000 or less from the viewpoint of synthesis. The weight average molecular weight in this specification is a value calculated as polystyrene by GPC (gel permeation chromatography).

[0044] The resin forming the resin layer preferably has a carboxy group and an acid value of 5 to 70 mgKOH / g. When the acid value is in the above range, when the resin layer is provided on the first colloidal crystal layer, a homogeneous resin layer with excellent wettability and less unevenness can be obtained, and the color development of the laminate is good. In addition, when the second colloidal crystal layer is provided on the resin layer, the resin forming the resin layer is prevented from redissolving in water and penetrating into the voids of the second colloidal crystals, and the color development of the laminate is good.

[0045] (Formation of resin layer) There are no particular limitations on the method for forming the resin layer, but for example, the resin layer can be formed by applying a resin layer composition containing resin fine particles and water onto the first colloidal crystal layer. The resin layer composition may contain a colorant, a nonionic surfactant, a crosslinking agent, etc., for the purpose of improving coatability, coating resistance, and color development of the laminate, within a range that does not adversely affect the particle arrangement and various physical properties of the laminate. As the colorant, the nonionic surfactant, and the crosslinking agent, those described in the section on the colloidal crystal layer above can be used.

[0046] <Production of Laminate> The laminate of the present invention comprises at least a base layer and a layer that develops color due to the interference of light, and the layer that develops color due to the interference of light may comprise, from the base layer side, a first colloidal crystal layer containing core-shell type resin particles, a resin layer having a glass transition point of -30 to 50°C, and a second colloidal crystal layer containing core-shell type resin particles, in this order, and there are no particular limitations on the method for producing the laminate. A preferred method for producing the laminate comprises the following steps 1 to 3, in this order: Step 1) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto a base layer to form a first colloidal crystal layer. Step 2) A step of applying a composition for a resin layer, which contains fine resin particles having a glass transition point of −30 to 50° C., onto the first colloidal crystal layer to form a resin layer. Step 3) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto the resin layer to form a second colloidal crystal layer. When each layer is formed, a drying step may be included as necessary.

[0047] The method for applying the colloidal crystal composition and the resin layer composition is not particularly limited, and examples thereof include printing methods that do not use a plate, such as an inkjet method, a spray method, a dipping method, or a spin coating method; and printing methods that use a plate, such as an offset gravure coater, a gravure coater, a doctor coater, a bar coater, a blade coater, a flexo coater, or a roll coater; and can be appropriately selected. When the drying step is included, the drying method is not particularly limited and can be appropriately selected from known methods such as heat drying, hot air drying, infrared drying, microwave drying, and drum drying. The drying method may be used alone or in combination of two or more, but from the viewpoint of reducing damage to the substrate and drying efficiently, it is preferable to use hot air drying. The drying temperature is preferably in the range of 25 to 80°C.

[0048] From the viewpoint of color development of the laminate, the thickness of the first and second colloidal crystal layers is preferably in the range of 2.0 to 20 μm. The first colloidal crystal layer and the second colloidal crystal layer may be of the same thickness or may be of different thicknesses. From the viewpoint of color development, the combined thickness of the first colloidal crystal layer and the second colloidal crystal layer is preferably in the range of 5.0 to 30 μm.

[0049] The thickness of the resin layer is preferably in the range of 1.0 to 20 μm. When the thickness of the resin layer is 1.0 μm or more, the uneven structure derived from the first colloidal crystal layer is reduced, and the second colloidal crystal layer can be formed on a smooth resin layer, resulting in good color development of the laminate. When the thickness of the resin layer is 20 μm or less, when light is incident on the laminate, the light that has passed through the second colloidal crystal layer easily reaches the first colloidal crystal layer, resulting in better color development of the laminate.

[0050] [Base material layer] The substrate layer in the present invention is not particularly limited and can be selected from known substrates. Examples of the substrate layer include thermoplastic resin substrates such as polyvinyl chloride sheet, polyethylene terephthalate (PET) film, polypropylene (PP) film, polyethylene (PE) film, nylon (Ny) film, polystyrene film, and polyvinyl alcohol film; metal substrates such as aluminum foil; glass substrates; and coated paper substrates. The substrate layer may have a smooth surface or may have irregularities. It may be transparent, semi-transparent, or opaque, and may be colored in advance, for example, black, to make the color of the colloidal crystals more clear. The substrate layer may be subjected to a corona treatment or plasma treatment for the purpose of improving the coatability of the colloidal crystal layer composition, and may have a primer layer. These substrate layers may be used alone or in combination of two or more layers.

[0051] [Overcoat layer] The laminate of the present invention may further have an overcoat layer on the second colloidal crystal layer for the purpose of improving the film resistance. The overcoat layer is not particularly limited and can be appropriately selected from known materials depending on the application. The thickness of the overcoat layer is preferably in the range of 1.0 to 20 μm. EXAMPLES

[0052] The present invention will be described in more detail below with reference to examples, but the following examples are not intended to limit the scope of the present invention. In the examples, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

[0053] <Average particle size and coefficient of variation Cv value> The average particle size was measured by diluting the sample 500 times with water and measuring about 5 ml of the diluted solution by dynamic light scattering measurement. The measuring device used was Nanotrack UPA (manufactured by Microtrack Bell Co., Ltd.). The peak of the obtained volumetric particle size distribution data (histogram) was taken as the average particle size. The coefficient of variation Cv value, which indicates the uniformity of the particle size, was calculated from the following formula. Formula: Coefficient of variation Cv value (%) = standard deviation of particle size / average particle size x 100 [In the formula, the units of standard deviation and average particle size are the same]

[0054] <Glass transition temperature (Tg)> The glass transition point was measured by DSC (differential scanning calorimeter, manufactured by TA Instruments). Specifically, about 2 mg of a sample obtained by drying a sample was weighed on an aluminum pan, the aluminum pan was set in a DSC measurement holder, and the glass transition point was obtained by reading the baseline shift (inflection point) toward the endothermic side of the DSC curve obtained under the temperature increase condition of 5° C. / min.

[0055] <Weight average molecular weight> The weight average molecular weight was determined by polystyrene conversion using GPC (gel permeation chromatography). More specifically, the dried resin was dissolved in tetrahydrofuran to prepare a 0.2% solution, and the weight average molecular weight was measured using the following equipment and measurement conditions. For resins that were insoluble due to high molecular weight and difficult to measure, the weight average molecular weight was considered to be 1 million or more. Equipment: HLC-8320-GPC system (Tosoh Corporation) Column: TSKgel-SuperMultiporeHZ-M0021488 4.6mm I.D. x 15cm x 3 (molecular weight measurement range: 2,000 to approx. 2,000,000) Elution solvent: Tetrahydrofuran Standard material: polystyrene (manufactured by Tosoh Corporation) Flow rate: 0.6 mL / min, amount of sample solution used: 10 μL, column temperature: 40°C.

[0056] <Production of resin particles> (Production example 1) Resin fine particle dispersion 1 A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser was charged with 95.6 parts of water. Next, 5.0% of an emulsion of ethylenically unsaturated monomers prepared by mixing and stirring 97.0 parts of styrene, 2.0 parts of acrylic acid, 1.0 parts of 3-methacryloxypropyltriethoxysilane, 1.0 parts of Aqualon AR-10 (anionic reactive surfactant manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 39.3 parts of water was added to the reaction vessel. After the internal temperature of the reaction vessel was raised to 70°C and sufficient nitrogen replacement was performed, 5.7 parts of a 2.5% aqueous solution of potassium persulfate was added as an initiator to start emulsion polymerization. The internal temperature was raised to 80°C and maintained at that temperature, while the remainder of the emulsion of the ethylenically unsaturated monomer in the first stage and 4.0 parts of a 2.5% aqueous solution of potassium persulfate were added dropwise over a period of 2 hours to react with each other, synthesizing core particles. 20 minutes after the completion of the first-stage dropping, the dropwise addition of the second-stage ethylenically unsaturated monomer emulsion, which was separately prepared by mixing and stirring 15.3 parts of methyl methacrylate, 26.8 parts of n-butyl acrylate, 0.9 parts of acrylic acid, 0.4 parts of AR-10, and 16.9 parts of ion-exchanged water, was started. While maintaining the internal temperature at 80° C., the emulsion of the second-stage ethylenically unsaturated monomer and 1.7 parts of a 2.5% aqueous solution of potassium persulfate were added dropwise over a period of 2 hours to react with each other, synthesizing a shell. Next, water was added to adjust the solid content to 45.0%, and a core-shell type resin fine particle dispersion 1 was obtained. The average particle size of the obtained resin fine particle dispersion 1 was 225 nm, and the Cv value was 25.9%. The Tg of the core was 100.1°C, and the Tg of the shell was -12.7°C.

[0057] (Production Examples 2-24) Resin fine particle dispersion 2-24 Core-shell type resin fine particle dispersions 2 to 24 were obtained in the same manner as in Production Example 1, except that the blending compositions were changed as shown in Table 1. In Production Examples 6, 7, 8, and 9, the amount of the emulsion of the ethylenically unsaturated monomer charged in the reaction vessel was changed from 5.0% to 8.0%, 7.0%, 2.5%, and 2.0%, respectively.

[0058] (Production Example 25) Resin fine particle dispersion 25 A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser was charged with 95.6 parts of water. Next, 5.0% of an emulsion of ethylenically unsaturated monomers prepared by mixing and stirring 97.0 parts of styrene, 2.0 parts of acrylic acid, 1.0 part of 3-methacryloxypropyltriethoxysilane, 1.0 part of Aqualon AR-10, and 39.3 parts of water was added to the reaction vessel. After the internal temperature of the reaction vessel was raised to 70°C and sufficient nitrogen replacement was performed, 5.7 parts of a 2.5% aqueous solution of potassium persulfate was added as an initiator to initiate emulsion polymerization. The internal temperature was raised to 80°C and maintained at that temperature, while the remaining emulsion of the ethylenically unsaturated monomer and 4.0 parts of a 2.5% aqueous solution of potassium persulfate were added dropwise over 2 hours to advance the reaction and synthesize resin microparticles. Next, water was added to adjust the solid content to 39.4%, and resin fine particle dispersion 25 was obtained. The average particle size of the obtained resin fine particle dispersion 25 was 201 nm, the Cv value was 27.0%, and the Tg was 100.1°C.

[0059] (Production Examples X-1, X-2) Resin fine particle dispersions X-1, X-2 Core-shell type resin fine particle dispersions X-1 and X-2 were obtained in the same manner as in Production Example 1, except that the composition shown in Table 1 was changed.

[0060] <Production of Resin Layer Composition> (Production Example 26) Resin layer composition A-1 95.6 parts of water was charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. Next, 5.0% of an emulsion of ethylenically unsaturated monomers prepared by mixing and stirring 46.8 parts of styrene, 50.2 parts of n-butyl acrylate, 2.0 parts of acrylic acid, 1.0 part of 3-methacryloxypropyltriethoxysilane, 1.0 part of Aqualon AR-10, and 39.3 parts of water was added to the reaction vessel. After raising the internal temperature of the reaction vessel to 70 °C and sufficiently performing nitrogen substitution, 5.7 parts of a 2.5% aqueous solution of potassium persulfate as an initiator was added to initiate emulsion polymerization. While raising the internal temperature to 80 °C and maintaining the temperature, the remaining portion of the emulsion of ethylenically unsaturated monomers and 4.0 parts of a 2.5% aqueous solution of potassium persulfate were added dropwise over 2 hours to proceed with the reaction, and resin fine particles a-1 were synthesized. The average particle diameter of the obtained resin fine particles a-1 was 225 nm, the Cv value was 25.9%, the Tg was 2.0 °C, the weight average molecular weight was 1,000,000 or more, and the acid value was 15.4 mgKOH / g. Next, water was added to adjust the solid content concentration to 39.4% to obtain a resin layer composition A-1.

[0061] (Production Examples 27 to 54) Resin layer compositions A-2 to 29 Resin fine particles a-2 to 29 were obtained in the same manner as in Production Example 26, except that the composition shown in Tables 2 and 3 was changed. Next, water was added to adjust the solid content concentration to 39.4% to obtain resin layer compositions A-2 to 29, respectively. In Production Example 31, in addition to 5.0% of the emulsion of ethylenically unsaturated monomers, 0.5 part of Aqualon AR-10 was charged into the reaction vessel. In Production Example 32, the amount of the emulsion of ethylenically unsaturated monomers charged into the reaction vessel was changed from 5.0% to 2.5%.

[0062] [Table 1-1]

[0063] [Table 1-2]

[0064] [Table 2]

[0065] [Table 3]

[0066] The abbreviations in Tables 1 to 3 are as follows. Aqualon AR-10: Anionic reactive surfactant (polyoxyethylene styrenated phenyl ether sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Aqualon KH-10: Anionic reactive surfactant (polyoxyethylene alkyl ether sulfates, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Hitenol NF-08: Anionic non-reactive surfactant (polyoxyethylene styrenated phenyl ether sulfates, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Aqualon AN-10: Nonionic reactive surfactant (polyoxyalkylene styrenated phenyl ether, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Noigen EA-87: Nonionic non-reactive surfactant (polyoxyethylene styrenated phenyl ethers, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0067] <Production of Composition for Colloidal Crystal Layer> (Production Example 55) Colloidal Crystal Layer Composition 1 To 100.0 parts of the resin fine particle dispersion 1, 3.8 parts of BONJET BLACK CW-1 (surface modified carbon black, average particle diameter 62 nm, pigment content 20.0%) manufactured by Orient Chemical Industry Co., Ltd., 5.0 parts of diethylene glycol monobutyl ether (BDG), and 1.0 part of Emulgen 1108 manufactured by Kao Corporation were added as dispersion 1, and the mixture was stirred to obtain composition 1 for colloidal crystal layer.

[0068] (Production Examples 56 to 79) Colloidal Crystal Layer Compositions 2 to 25 Compositions 2 to 25 for colloidal crystal layer were obtained in the same manner as in Production Example 55, except that the blending compositions were changed as shown in Table 4.

[0069] (Production Examples Y-1 and Y-2) Compositions for Colloidal Crystal Layer Y-1 and Y-2 Compositions Y-1 and Y-2 for colloidal crystal layer were obtained in the same manner as in Production Example 55, except that the blending composition was changed to that shown in Table 4.

[0070] [Table 4]

[0071] The abbreviations in Table 4 are as follows: Dispersion 1: Surface modified carbon black (average particle size 62 nm, pigment content 20.0%, olivine Ento Chemical Industry Co., Ltd. BONJET BLACK CW-1) BDG: Diethylene glycol monobutyl ether Emulgen 1108: Nonionic surfactant (polyoxyethylene alkyl ether type, manufactured by Kao Corporation)

[0072] <Production of primer composition> (Production Example 80) Primer Composition 1 A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser was charged with 95.6 parts of water and 0.25 parts of Aqualon AR-10. Next, 5.0% of an emulsion of ethylenically unsaturated monomers, which had been previously prepared by mixing and stirring 10.0 parts of styrene, 25.0 parts of methyl methacrylate, 16.0 parts of 2-ethylhexyl acrylate, 35.0 parts of n-butyl acrylate, 2.0 parts of acrylic acid, 1.0 part of 3-methacryloxypropyltriethoxysilane, 1.0 part of Aqualon AR-10, and 39.3 parts of water, was further added to the reaction vessel. After the internal temperature of the reaction vessel was raised to 70°C and sufficient nitrogen replacement was performed, 5.7 parts of a 2.5% aqueous solution of potassium persulfate was added as an initiator to initiate emulsion polymerization. The internal temperature was raised to 80°C and while maintaining the temperature, the remaining emulsion of the ethylenically unsaturated monomer and 4.0 parts of a 2.5% aqueous solution of potassium persulfate were added dropwise over 2 hours to advance the reaction, synthesizing a resin microparticle dispersion for primers. After the reaction was completed, 1.9 parts of 25% aqueous ammonia was added to neutralize the mixture, and water was added to adjust the solid content of the dispersion of resin particles for primer to 40.0%. The average particle size of the resin particles for primer was 96 nm, the Cv value was 25.4%, and the Tg was -3.2°C. To the obtained primer resin microparticle dispersion, 2.0 parts of n-propyl alcohol and 10.0 parts of BONJET BLACK CW-1 (surface-modified carbon black, average particle diameter 62 nm, pigment content 20.0%) manufactured by Orient Chemical Industry Co., Ltd. were added and mixed with stirring to obtain primer composition 1.

[0073] <Production of Laminate> [Example 1] Laminate 1 Primer composition 1 was applied to the corona-treated surface of a biaxially oriented polypropylene (OPP) film (Futamura FOR, thickness 20 μm) using a bar coater (OSG System Products, OSP-05) so that the thickness after drying would be 2.0 μm, and then dried in an oven at 80°C for 3 minutes to form a primer layer. A Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 70 lines / cm) was set on a simple gravure coater (Nissho Gravure's GRAVO-PROOF MINI), and colloidal crystal layer composition 23 was printed on the primer layer and dried in an oven at 50°C for 3 minutes to form a first colloidal crystal layer. The thickness of the first colloidal crystal layer was 5.0 μm. Next, the resin layer composition A-1 was applied onto the first colloidal crystal layer using a bar coater (OSP-04), and then dried in an oven at 80° C. for 3 minutes to form a resin layer. The thickness of the resin layer was 1.5 μm. Next, a Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 70 lines / cm) was set in a simple gravure coater, and colloidal crystal layer composition 23 was printed on the resin layer and dried in an oven at 50°C for 3 minutes to form a second colloidal crystal layer. The thickness of the second colloidal crystal layer was 5.0 µm. In this way, a laminate 1 having a structure of OPP / primer layer / first colloidal crystal layer / resin layer / second colloidal crystal layer was obtained.

[0074] [Examples 2 to 56, 58 to 60, Comparative Examples 1, 2, 5] Laminates 2 to 56, 58 to 60, 65, 66, 69 Laminates 2 to 56, 58 to 60, 65, 66, and 69 were obtained in the same manner as in Example 1, except that the compositions were changed as shown in Tables 5 to 7. In Examples 58 to 60, the gravure cylinder was changed to the one shown below, and the thicknesses of the first and second colloidal crystal layers were adjusted. Example 58: Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 200 lines / cm) Example 59: Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 170 lines / cm) Example 60: Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 130 lines / cm)

[0075] [Example 57] Laminate 57 Primer composition 1 was applied to the corona-treated surface of a biaxially oriented polypropylene film (Futamura FOR, thickness 20 μm) using a bar coater (OSP-05) so that the thickness after drying would be 2.0 μm, and then dried in an oven at 80°C for 3 minutes to form a primer layer. Composition 23 for colloidal crystal layer was printed on the primer layer using Flexiproof 100 (anilox roller 80 lines / cm) and dried in an oven at 50°C for 3 minutes to form a first colloidal crystal layer. The thickness of the first colloidal crystal layer was 1.5 µm. Next, the resin layer composition A-19 was applied onto the first colloidal crystal layer using a bar coater (OSP-04), and then dried in an oven at 80° C. for 3 minutes to form a resin layer. The thickness of the resin layer was 1.5 μm. Next, using Flexiproof 100 (anilox roller 80 lines / cm), the colloidal crystal layer composition 23 was printed onto the resin layer, and dried in an oven at 50°C for 3 minutes to form a second colloidal crystal layer. The thickness of the second colloidal crystal layer was 1.5 µm. In this way, a laminate 57 having a structure of OPP / primer layer / first colloidal crystal layer / resin layer / second colloidal crystal layer was obtained.

[0076] [Example 61] Laminate 61 Primer composition 1 was applied to the corona-treated surface of a biaxially oriented polypropylene film (Futamura FOR, thickness 20 μm) using a bar coater (OSP-05) so that the thickness after drying would be 2.0 μm, and then dried in an oven at 80°C for 3 minutes to form a primer layer. Using a bar coater (OSP-47), the colloidal crystal layer composition 23 was printed on the primer layer and dried in an oven at 50° C. for 3 minutes to form a first colloidal crystal layer. The thickness of the first colloidal crystal layer was 18.0 μm. Next, the resin layer composition A-19 was applied onto the first colloidal crystal layer using a bar coater (OSP-04), and then dried in an oven at 80° C. for 3 minutes to form a resin layer. The thickness of the resin layer was 1.5 μm. Next, using a bar coater (OSP-22), the colloidal crystal layer composition 23 was printed onto the resin layer, and dried in an oven at 50°C for 3 minutes to form a second colloidal crystal layer. The thickness of the second colloidal crystal layer was 10.0 µm. In this way, a laminate 61 having a structure of OPP / primer layer / first colloidal crystal layer / resin layer / second colloidal crystal layer was obtained.

[0077] [Examples 62 and 63] Laminates 62 and 63 Laminates 62 and 63 were obtained in the same manner as in Example 61, except that the composition was changed as shown in Table 7. In Examples 62 and 63, the thicknesses of the first and second colloidal crystal layers were adjusted using a bar coater (OSP-47) and a bar coater (OSP-52), respectively.

[0078] [Example 64] A Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 70 lines / cm) was set in a simple gravure coater, and colloidal crystal layer composition 23 was printed on the corona-treated surface of a biaxially oriented polypropylene film (Futamura FOR, thickness 20 μm), which was then dried in an oven at 50° C. for 3 minutes to form a first colloidal crystal layer. The thickness of the first colloidal crystal layer was 5.0 μm. Next, the resin layer composition A-19 was applied onto the first colloidal crystal layer using a bar coater (OSP-04), and then dried in an oven at 80° C. for 3 minutes to form a resin layer. The thickness of the resin layer was 1.5 μm. Next, a Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 70 lines / cm) was set in a simple gravure coater, and colloidal crystal layer composition 23 was printed on the resin layer and dried in an oven at 50°C for 3 minutes to form a second colloidal crystal layer. The thickness of the second colloidal crystal layer was 5.0 µm. In this way, a laminate 64 having a structure of OPP / first colloidal crystal layer / resin layer / second colloidal crystal layer was obtained.

[0079] [Comparative Example 3] Laminate 67 A laminate 67 was obtained in the same manner as in Example 1 with the composition A-30 for the resin layer using SYLGARD184 solution (a silicone elastomer precursor manufactured by Toray Dow; main component A liquid (solid content 99.6%): crosslinker B liquid (solid content 76.2%) = 10:1 (mass ratio), Tg is -120°C) with the configuration shown in Table 7.

[0080] [Comparative Example 4] Laminate 68 A laminate 68 was obtained in the same manner as in Example 1 with the configuration shown in Table 7 using a 20% aqueous solution of polyvinyl alcohol (Poval 22-88 manufactured by Kuraray, Tg of 70° C.) as the resin layer composition A-31.

[0081] [Comparative Example 6] Laminate 70 Primer composition 1 was applied to the corona-treated surface of a biaxially oriented polypropylene film (Futamura FOR, thickness 20 μm) using a bar coater (OSP-05) so that the thickness after drying would be 2.0 μm, and then dried in an oven at 80°C for 3 minutes to form a primer layer. Next, a Toyo FPP gravure cylinder (engraving method: helio, cell shape: compressed, line count: 70 lines / cm) was set in a simple gravure coater, and colloidal crystal layer composition 23 was printed on the primer layer and dried in an oven at 50°C for 3 minutes to form a colloidal crystal layer. The thickness of the colloidal crystal layer was 5.0 µm. In this manner, a laminate 70 having a structure of OPP / primer layer / colloidal crystal layer was obtained.

[0082] [Examples Z-1 and Z-2] Laminates Z-1 and Z-2 Except for changing the composition shown in Table 7, the same method as in Example 1 was used to obtain laminates Z-1 and Z-2.

[0083] <Evaluation of the laminate> The obtained laminate was evaluated. The results are shown in Tables 5 to 7.

[0084] (Color development) The reflectance spectrum of the laminate was measured in the wavelength range of 250 to 850 nm using an ultraviolet-visible near-infrared spectrophotometer (V-770D manufactured by JASCO Corporation, integrating sphere unit ISN-923). The reflectance at each wavelength is the relative reflectance measured using a standard white board with a known reflectance (SRS-99-010 manufactured by Labsphere) as a reference. For the obtained reflectance spectrum, the difference (ΔR) between the maximum reflectance due to the structural color and the baseline reflectance not due to the structural color was calculated. The larger the ΔR, the better the color development. The obtained ΔR was evaluated according to the following criteria. S: △R is 10% or more (very good) A: △R is 5% or more, less than 10% (good) B: △R is 2% or more and less than 5% (usable) C: △R is less than 2%, or the reflectance peak due to structural color cannot be identified (unusable)

[0085] (Substrate conformity) The laminate was cut into a 5 cm x 5 cm test piece and folded 180 degrees 5 times. The state of the laminate after folding was visually observed and evaluated according to the following criteria. S: No peeling or scratches (very good) A: The area of ​​peeling or damage is less than 5% of the test piece (good) B: The area of ​​peeling or damage is 5% or more and less than 10% of the test piece (usable) C: The area of ​​peeling or damage is 10% or more of the test piece (unusable)

[0086] (Indentation resistance) The laminate was cut into a test piece of 5 cm x 5 cm, and the condition of the laminate after being pressed with the pad of a finger 30 times was visually observed and evaluated according to the following criteria. S: No peeling or scratches (very good) A: The area of ​​peeling or scratches is less than 5% of the indented area (good) B: The area of ​​peeling or scratches is 5% or more but less than 10% of the indented area (usable) C: The area of ​​peeling or scratches is 10% or more of the indented area (not usable)

[0087] (Scratch resistance) The laminate was cut into a test piece of 5 cm x 5 cm, and rubbed with the pad of a finger 50 times, after which the state of the colloidal crystals was visually observed and evaluated according to the following criteria. S: No peeling or scratches (very good) A: The area of ​​peeling or scratches is less than 5% of the indented area (good) B: The area of ​​peeling or scratches is 5% or more but less than 10% of the indented area (usable) C: The area of ​​peeling or scratches is 10% or more of the indented area (not usable)

[0088] [Table 5]

[0089] [Table 6]

[0090] [Table 7]

[0091] All of the laminates of the present invention exhibited good color development, and were also excellent in terms of substrate conformability, indentation resistance, and scratch resistance. In particular, laminates in which the resin layer had a thickness of 1.0 to 20 μm exhibited remarkably excellent color development. Furthermore, laminates in which the combined thickness of the first colloidal crystal layer and the second colloidal crystal layer was in the range of 5.0 to 30 μm exhibited excellent color development. On the other hand, the laminates of the comparative examples were inferior in any one of color development, substrate conformability, indentation resistance, and scratch resistance.

Claims

1. A laminate including at least a base layer and a layer that develops color by interference of light, the substrate layer is at least one selected from the group consisting of a thermoplastic resin substrate, a metal substrate, a glass substrate, and a coated paper substrate; The layer that develops color due to the interference of light is, from the base layer side, a first colloidal crystal layer containing core-shell type resin fine particles; A resin layer having a glass transition point of −30 to 50° C.; a second colloidal crystal layer containing core-shell type resin fine particles, the resin layer is formed from a polymer of an ethylenically unsaturated monomer, A laminate, wherein the core-shell type resin fine particles have a shell formed from a polymer of an ethylenically unsaturated monomer.

2. 2. The laminate according to claim 1, wherein the average particle diameter of the core-shell type resin fine particles is 180 to 330 nm.

3. 3. The laminate according to claim 1, wherein the core-shell type resin fine particles have a shell content of 10 to 300% by mass based on the mass of the core.

4. The laminate according to any one of claims 1 to 3, wherein the core-shell type resin microparticles have a shell in an amount of 10 to 50% by mass based on the mass of the core, the core has a glass transition point of 60°C or higher, and the shell has a glass transition point of -50 to 20°C.

5. 5. The laminate according to claim 1, wherein the core-shell type resin fine particles are polymerized using a reactive surfactant.

6. The laminate according to any one of claims 1 to 5, wherein the weight average molecular weight of the resin forming the resin layer is 50,000 or more.

7. The laminate according to any one of claims 1 to 6, wherein the acid value of the resin forming the resin layer is 5 to 70 mgKOH / g.

8. The laminate according to any one of claims 1 to 7, wherein the resin layer has a thickness of 1.0 to 20 µm.

9. A method for producing a laminate comprising at least a base layer and a layer that develops color through the interference of light, the method comprising the following steps 1 to 3 in this order: Step 1) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto a substrate layer to form a first colloidal crystal layer. Step 2) A step of applying a resin layer composition containing resin fine particles having a glass transition point of −30 to 50° C. onto the first colloidal crystal layer to form a resin layer. Step 3) A step of applying a composition for colloidal crystals containing core-shell type resin fine particles onto the resin layer to form a second colloidal crystal layer. However, the substrate layer is one or more selected from the group consisting of a thermoplastic resin substrate, a metal substrate, a glass substrate, and a coated paper substrate, the resin microparticles having a glass transition point of −30 to 50° C. are a polymer of an ethylenically unsaturated monomer, and the core-shell type resin microparticles have a shell formed from a polymer of an ethylenically unsaturated monomer.

Images