JP2023091997A - Laminated body and method for manufacturing laminated body - Google Patents

Abstract

To provide a laminated body that achieves both hardness and flexibility by making full use of commercially available conventional active energy ray-curable coating agents with high hardness and active energy ray-curable coating agents with flexibility, and a method for producing the same.SOLUTION: The foregoing problem is solved by a laminated body including a first layer and a second layer on a substrate, in which the first layer comprises continuous layers of synthetic resin layers A having a gloss retention rate of less than 70%, and the second layer comprises discontinuous layers in which synthetic resin layers B having a gloss retention rate of 90% or more are evenly arranged, and a total area of the second layer is 20 to 60% of a total area of the first layer.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a laminate having both hardness and flexibility and a method for producing the same.

BACKGROUND ART Conventionally, active energy ray-curable coating agents such as ultraviolet rays have been used for the purpose of imparting aesthetic appearance and surface hardness to substrates such as plastics and wood. Active energy ray-curable coating agents are fast-curing and have high hardness, but they lack flexibility, and when the substrate after coating is subjected to bending treatment, etc., cracks occur in the coating film at the bent portion. there was a case.

Many attempts have been made to solve the problem of an active energy ray-curable coating agent that achieves both hardness and flexibility by using the composition itself of the coating agent (see, for example, Patent Documents 1 and 2). On the other hand, we would like to use both active energy ray-curable coating agents with high hardness and flexible active energy ray-curable coating agents that have been commercially available to achieve both hardness and flexibility. There is a demand.

JP 2021-17513 A JP 2018-115318 A

The problem to be solved by the present invention is to make full use of an active energy ray-curable coating agent having high hardness and a flexible active energy ray-curable coating agent, which have been commercially available in the past, to improve hardness and An object of the present invention is to provide a laminate having both flexibility and a method for producing the same.

The present inventors have solved the above problems by using the gravure coating method that has been conventionally used for applying active energy ray-curable coating agents to substrates such as plastics and wood.

That is, the present invention has a first layer and a second layer in this order on a substrate, the first layer is a continuous layer of a synthetic resin layer A having a gloss retention rate of less than 70%, and the second layer is , the synthetic resin layer B having a gloss retention rate of 90% or more is uniformly arranged in a non-continuous layer, and the total area of the second layer is 20 to 60% of the total area of the first layer. A laminate is provided.

Further, the present invention provides a laminate in which the synthetic resin layer B is a cured resin layer B cured by active energy rays on a discontinuous layer uniformly arranged by gravure printing with a gravure plate having a halftone density of 20% to 60%. I will provide a.

Further, the present invention has a first layer and a second layer in this order on the substrate, the first layer is a continuous layer of the synthetic resin layer A having a gloss retention rate of less than 70%, and the second layer is , a laminate composed of discontinuous layers in which synthetic resin layers B having a gloss retention rate of 90% or more are evenly arranged, and the total area of the second layer is 20 to 60% of the total area of the first layer. wherein the step (1) of forming the first layer on a base material with a printing machine or a coating machine;
Having a step (2) of forming the second layer by gravure printing with a gravure plate having a halftone density of 20% to 60%, and a step (3) of curing with active energy rays in the atmosphere or nitrogen atmosphere, in this order. To provide a method for manufacturing a laminate characterized by

According to the present invention, the active energy ray-curable coating agent having high hardness and the active energy ray-curable coating agent having flexibility, which have been commercially available, are used as they are, and both hardness and flexibility are achieved. A laminate and a manufacturing method thereof can be provided.

(Laminate)
The laminate of the present invention has a first layer and a second layer in this order on a substrate, the first layer being a continuous layer of a synthetic resin layer A having a gloss retention rate of less than 70%, and a second layer. The layer consists of discontinuous layers in which synthetic resin layers B having a gloss retention rate of 90% or more are evenly arranged, and the total area of the second layer is 20 to 60% of the total area of the first layer. It is characterized by

(Base material)
The substrate used in the present invention is not particularly limited, and any substrate suitable for the desired purpose can be used as appropriate. The substrate is preferably a flexible plastic film or sheet substrate.
For example, for building materials, polyethylene (LLDPE: low density polyethylene, HDPE: high density polyethylene, MDOPE: uniaxially oriented polyethylene, OPE: biaxially oriented polyethylene) and polypropylene (CPP: unoriented polypropylene film, OPP: biaxially oriented polypropylene) film), polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-propylene-butene copolymer, polyolefin thermoplastic elastomer, etc. Films and sheet-like substrates made of resins can be mentioned.
Film and sheet-like substrates made of polyethylene terephthalate (PET), polystyrene, polyamide, polyacrylonitrile, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, ethylene-vinyl alcohol copolymer and the like are also included.
Further, these substrates may be single-layered substrates or multiple-layered substrates.

To form a film- or sheet-like base material, for example, a molding method such as a calendering method, an inflation method, or a T-die extrusion method can be used. The thickness of these is not particularly limited and can be set according to product properties, but it is usually about 40 to 150 μm, preferably about 50 to 100 μm.

Additives may be added to the base material, if necessary. Examples of additives include fillers such as calcium carbonate and clay, flame retardants such as magnesium hydroxide, antioxidants, lubricants, foaming agents, and colorants. The blending amount of the additive can be appropriately set according to the product characteristics.

One side or both sides of the substrate may be subjected to surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromic acid treatment, etc., if necessary. For example, when performing corona discharge treatment, the surface tension of the substrate surface should be 30 dyne or more, preferably 40 dyne or more. The surface treatment may be carried out according to a conventional method for each treatment.

Substrates such as paper, wood, and leather can also be used without problems. For example, as the paper, a known paper base material can be used without particular limitation. Specifically, the paper is produced by a known paper machine using natural fibers for papermaking such as wood pulp. Examples of natural fibers for papermaking include wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as Manila hemp pulp, sisal pulp and flax pulp, and pulp obtained by chemically modifying these pulps. The types of pulp that can be used include chemical pulp, ground pulp, chemi-grand pulp, thermomechanical pulp, and the like prepared by sulfate cooking, acidic/neutral/alkaline sulfite cooking, soda salt cooking, and the like. Moreover, various types of commercially available fine paper, coated paper, lined paper, impregnated paper, cardboard, paperboard, etc. can also be used.

(gloss retention rate)
In the present invention, the gloss retention rate of the first layer or the second layer, which will be described later, is a value obtained by the following method after providing a synthetic resin layer A or B having a thickness of 10 μm on the substrate.
(Method for measuring gloss retention)
A synthetic resin layer A or a synthetic resin layer B having a thickness of 10 μm is formed on a polyester film substrate.
The gloss value of the formed synthetic resin layer A or B is measured using a gloss meter ("MULTI GLOSS 268A" manufactured by Konica Minolta).
The measurement conditions for the gloss value are an incident angle of 60° and a reflection angle of 60°. The value at this time is taken as the gloss value of the untested surface.
Subsequently, the surface of the synthetic resin layer A or B is reciprocated 10 times with steel wool (Bonstar #0000) under a load of 1.5 kg, and then the gloss value is measured in the same manner. The value at this time is taken as the gloss value of the test surface.
Using these values, the gloss retention rate was calculated according to the following formula. A gloss retention rate of 70% or more when formed into a laminate is within a practical range.

Gloss retention rate (%) = (gloss value of test surface/gloss value of untested surface) x 100

(first layer)
In the laminate of the present invention, the first layer consists of a continuous layer of synthetic resin layer A having a gloss retention rate of less than 70%.
Among others, the synthetic resin layer A is preferably a cured layer of an active energy ray-curable resin composition.
In the present invention, "(meth)acryloyl group" refers to one or both of an acryloyl group and a methacryloyl group. Moreover, the "compound having a (meth)acryloyl group" may be referred to as (meth)acrylate. "(Meth)acrylate" refers to one or both of acrylate and methacrylate.

(Synthetic resin layer A)
As the active energy ray-curable resin composition which is the raw material of the synthetic resin layer A, (meth)acrylate oligomers such as acrylic (meth)acrylate and polyurethane (meth)acrylate are preferable.
The (meth)acrylate oligomer preferably has a number average molecular weight of 1,000 or more.

Furthermore, in the laminate of the present invention, various (meth)acrylate monomers may be used in combination as the raw material for the synthetic resin layer A. Examples of the (meth)acrylate monomers include monofunctional (meth)acrylates, polyfunctional (meth)acrylates, polymerizable oligomers, and the like.

Examples of monofunctional (meth)acrylates include ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxy Ethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate , 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylates, isobornyl (meth)acrylates, dicyclopentanyl (meth)acrylates, dicyclopentenyloxyethyl (meth)acrylates, ethoxyethoxyethanol acrylic acid polymer esters, and the like.

Examples of bifunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecanedi Methanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, etc. dihydric alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, 4 mol per 1 mol of neopentyl glycol di(meth)acrylates of diols obtained by adding ethylene oxide or propylene oxide, di(meth)acrylates of diols obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A, and the like. .

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol poly Poly(meth)acrylates of trihydric or higher polyhydric alcohols such as (meth)acrylates, tri(meth)acrylates of triols obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of glycerin, trimethylolpropane Di or tri(meth)acrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol, diol of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A Examples include poly(meth)acrylates of polyoxyalkylene polyols such as (meth)acrylates.

Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (sometimes abbreviated as DPHA), ditrimethylolpropane tetraacrylate (sometimes abbreviated as DTMPTA), which is a (meth)acrylate with two or more functions, Trimethylolpropane ethylene oxide adduct tri(meth)acrylate, which is a triol tri(meth)acrylate obtained by adding 3 mol or more of ethylene oxide to 1 mol of trimethylolpropane, may also be used. A typical example of the trimethylolpropane ethylene oxide adduct tri(meth)acrylate is trimethylolpropane ethylene oxide (hereinafter ethylene oxide may be referred to as "EO") modified (n≈3) triacrylate. be done.

Examples of polymerizable oligomers other than (meth)acrylate oligomers such as urethane (meth)acrylate described above include amine-modified polyether acrylate, amine-modified epoxy acrylate, amine-modified aliphatic acrylate, amine-modified polyester acrylate, amino (meth) Examples include amine-modified acrylates such as acrylates, polyester (meth)acrylates, polyether (meth)acrylates, polyolefin (meth)acrylates, and polystyrene (meth)acrylates.

Active energy rays for curing the active energy ray-curable resin composition, which is the raw material of the synthetic resin layer A in the present invention, include ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays.

(Photoinitiator)
As the active energy ray-curable resin composition which is the raw material of the synthetic resin layer A in the invention, a photopolymerization initiator is usually used when curing with ultraviolet rays or the like. As the photopolymerization initiator used at this time, a known one may be used.

Among them, radical polymerization type photopolymerization initiators are preferable, and examples include α-hydroxyalkylketone photopolymerization initiators that do not cause discoloration of the solution when the active energy ray-curable compound is dissolved and cause little yellowing over time. Examples of α-hydroxyalkylketone photopolymerization initiators include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropane, -1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone and the like. Phenylglyoxolate-based photopolymerization initiators are also preferred. Examples of the phenylglyoxolate-based photopolymerization initiator include methylbenzoyl formate. Among them, 1-hydroxycyclohexylphenyl ketone is preferred.

Further, as other radical polymerization type photopolymerization initiators, monoacylphosphine oxide photopolymerization initiators having absorption wavelengths in the long wavelength region of ultraviolet rays may be used in appropriate combination. As the monoacylphosphine oxide-based photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,6 -dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, pivaloyl Examples include monoacylphosphine oxides such as phenylphosphinic acid isopropyl ester, and particularly, among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide has an emission wavelength of 385 nm or 395 nm. Having a UV absorption wavelength that matches the emission wavelength region of the LED is more preferable in terms of obtaining suitable curability and less yellowing of the cured film.

The photopolymerization initiators described above may be used alone, or two or more of them may be used in combination. The total amount of the photopolymerization initiator added is preferably in the range of 0.5% by mass to 30% by mass with respect to the total solid content of the active energy ray-curable resin composition. More preferably, it is in the range of 1% by mass to 25% by mass based on the total solid content of the active energy ray-curable resin composition.

(Other resins)
Furthermore, in the raw material of the synthetic resin layer A, in addition to the (meth)acrylate oligomers such as acrylic (meth)acrylate and polyurethane (meth)acrylate, known binder resins may be used in combination without particular limitation. For example, nitrocellulose, cellulose resins such as cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB), vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl isobutyl ether copolymer resin , rosin resins, polyurethane resins, polyamide resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, vinyl chloride resins such as polyvinyl chloride resins, polyester resins, alkyd resins, ketone resins, Cyclized rubber, chlorinated rubber, butyral, petroleum resin and the like can be mentioned.

(Organic solvent)
An organic solvent can also be added as a diluent to facilitate the coating of the first layer.
As the organic solvent, any solvent can be used as long as it dissolves the compound having a (meth)acryloyl group to be used. More preferably, it does not contain volatile organic compounds (VOCs) at 260°C.
The purpose is to thoroughly reduce the amount of evaporation of organic solvents into the atmosphere, that is, to reduce VOCs. Aliphatic or alicyclic hydrocarbons such as methylcyclohexane and ethylcyclohexane, esters such as ethyl acetate, butyl acetate and propyl acetate, alcohols such as methanol, ethanol, isopropyl alcohol and n-butanol, acetone, methyl ethyl ketone, methyl isobutyl It is preferable not to contain any of ketones such as ketones and cyclohexanone, alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether, and ether esters such as propylene glycol monomethyl ether acetate.
These organic solvents can also be used in combination as a mixed solvent.

The method of providing the first layer in the present invention, that is, the continuous layer of the synthetic resin layer A having a gloss retention rate of less than 70% is performed by the following method.
First, a continuous layer is formed on the substrate by the step (1) of forming the first layer with a printing machine or a coating machine.
For the first layer, the coating method for the continuous layer of the synthetic resin layer A having a gloss retention of less than 70% includes, for example, a roll coater, a gravure coater, a flexo coater, an air doctor coater, a blade coater, an air knife coater, a squeeze coater, Known means such as an impregnation coater, a transfer roll coater, a kiss coater, a curtain coater, a cast coater, a spray coater, a die coater, an offset printer, and a screen printer can be employed as appropriate. Among them, a gravure coater is preferable.

Next, it is preferable to produce a continuous layer of the synthetic resin layer A by irradiating the coating film obtained in the above step with an active energy ray of 30 to 1000 mJ/cm ² at least once if necessary.
The irradiation may be carried out in the atmosphere, or by injecting one or a mixed gas of two or more selected from nitrogen gas, carbon dioxide gas, and argon gas together with air or alone into the reaction vessel to increase the oxygen concentration to 8. %, if the active energy ray-curable coating agent can be irradiated with an active energy ray in a gas atmosphere, the curability of the coating film obtained in the above step can be advanced more efficiently. Among them, a nitrogen atmosphere is preferable.

The active energy rays of 30 to 1000 mJ/cm ² include ionizing radiation and electromagnetic waves such as ultraviolet rays, electron rays, α rays, β rays and γ rays, among which ultraviolet rays and electron rays are preferred.
Examples of specific energy sources or curing devices include germicidal lamps, ultraviolet fluorescent lamps, ultraviolet light emitting diodes (UV-LED), carbon arcs, metal halide lamps, xenon lamps, chemical lamps, low-pressure mercury lamps, and high-pressure mercury lamps for copying. , medium- or high-pressure mercury lamps, ultra-high-pressure mercury lamps, electrodeless lamps, metal halide lamps, ultraviolet rays using natural light as a light source, or electron beams from scanning or curtain electron beam accelerators.

When irradiating ultraviolet rays in a gas atmosphere with an oxygen concentration of less than 8%, a known ultraviolet irradiation device equipped with a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, or the like can be used. The amount of UV light during curing is preferably 30 mJ/cm ² or more for good curing efficiency, and 1000 mJ/cm ² or less from the viewpoint of preventing thermal damage to the substrate.

(Second layer)
In the laminate of the present invention, the second layer is a discontinuous layer in which the synthetic resin layers B having a gloss retention rate of 90% or more are evenly arranged.
Among others, the synthetic resin layer B is preferably a cured layer of an active energy ray-curable resin composition.

(Synthetic resin layer B)
As the active energy ray-curable resin composition, which is the raw material of the synthetic resin layer B in the present invention, (meth)acrylate oligomers such as acrylic (meth)acrylate and polyfunctional urethane acrylate are preferable.
The (meth)acrylate oligomer preferably has a number average molecular weight of 1,000 or more.

Furthermore, in the laminate of the present invention, various (meth)acrylate monomers may be used in combination as the raw material for the synthetic resin layer B. Examples of the (meth)acrylate monomers include monofunctional (meth)acrylates, polyfunctional (meth)acrylates, polymerizable oligomers, and the like.

Examples of monofunctional (meth)acrylates include ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxy Ethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate , 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylates, isobornyl (meth)acrylates, dicyclopentanyl (meth)acrylates, dicyclopentenyloxyethyl (meth)acrylates, ethoxyethoxyethanol acrylic acid polymer esters, and the like.

Examples of bifunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. , neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecanedi Methanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, etc. dihydric alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, 4 mol per 1 mol of neopentyl glycol di(meth)acrylates of diols obtained by adding ethylene oxide or propylene oxide, di(meth)acrylates of diols obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A, and the like. .

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol poly Poly(meth)acrylates of trihydric or higher polyhydric alcohols such as (meth)acrylates, tri(meth)acrylates of triols obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of glycerin, trimethylolpropane Di or tri(meth)acrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol, diol of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A Examples include poly(meth)acrylates of polyoxyalkylene polyols such as (meth)acrylates.

Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (sometimes abbreviated as DPHA), ditrimethylolpropane tetraacrylate (sometimes abbreviated as DTMPTA), which is a (meth)acrylate with two or more functions, Trimethylolpropane ethylene oxide adduct tri(meth)acrylate, which is a triol tri(meth)acrylate obtained by adding 3 mol or more of ethylene oxide to 1 mol of trimethylolpropane, may also be used. A typical example of the trimethylolpropane ethylene oxide adduct tri(meth)acrylate is trimethylolpropane ethylene oxide (hereinafter ethylene oxide may be referred to as "EO") modified (n≈3) triacrylate. be done.

Examples of the polymerizable oligomer include, in addition to the polyfunctional urethane acrylates described above, amine-modified acrylates such as amine-modified polyether acrylates, amine-modified epoxy acrylates, amine-modified aliphatic acrylates, amine-modified polyester acrylates, and amino (meth)acrylates, polyester (meth)acrylate, polyether (meth)acrylate, polyolefin (meth)acrylate, polystyrene (meth)acrylate, and the like.

(Photoinitiator)
As the active energy ray-curable resin composition which is the raw material of the synthetic resin layer B in the present invention, a photopolymerization initiator is usually used when curing with ultraviolet rays or the like. As the photopolymerization initiator used at this time, a known one may be used.

Among them, radical polymerization type photopolymerization initiators are preferable, and examples include α-hydroxyalkylketone photopolymerization initiators that do not cause discoloration of the solution when the active energy ray-curable compound is dissolved and cause little yellowing over time. Examples of α-hydroxyalkylketone photopolymerization initiators include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropane, -1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone and the like. Phenylglyoxolate-based photopolymerization initiators are also preferred. Examples of the phenylglyoxolate-based photopolymerization initiator include methylbenzoyl formate. Among them, 1-hydroxycyclohexylphenyl ketone and 1-phenyl-2-hydroxy-2-methylpropan-1-one are preferred.

Further, as other radical polymerization type photopolymerization initiators, monoacylphosphine oxide photopolymerization initiators having absorption wavelengths in the long wavelength region of ultraviolet rays may be used in appropriate combination. As the monoacylphosphine oxide-based photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,6 -dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, pivaloyl Examples include monoacylphosphine oxides such as phenylphosphinic acid isopropyl ester, and particularly, among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide has an emission wavelength of 385 nm or 395 nm. Having a UV absorption wavelength that matches the emission wavelength region of the LED is more preferable in terms of obtaining suitable curability and less yellowing of the cured film.

The photopolymerization initiators described above may be used alone, or two or more of them may be used in combination. The total amount of the photopolymerization initiator added is preferably in the range of 0.5% by mass to 30% by mass with respect to the total solid content of the active energy ray-curable resin composition. More preferably, it is in the range of 1% by mass to 25% by mass based on the total solid content of the active energy ray-curable resin composition.

(filler)
It is preferable to further add a filler to the active energy ray-curable resin composition which is the raw material of the synthetic resin layer B in the present invention. As the filler, any organic and/or inorganic filler can be used alone or in combination as long as it is known. Specifically, for example, inorganic particles such as silica, titanium oxide, alumina particles (aluminum oxide), aluminosilicates, calcium carbonate, barium sulfate, and glass, or acrylic resins, urethane resins, polycarbonate resins, silicone resins, polystyrene resins, etc. Organic particles, silicone beads and the like can be used. Among them, colloidal silica and aluminosilicate are preferable because they can be expected to have an effect of improving scratch resistance.

The total filler content is preferably 5 to 20% by mass, more preferably 10 to 18% by mass, of the total solid content of the active energy ray-curable resin composition. If the content is 5% by mass or more, the effect of scratch resistance can be obtained, and if it is less than 20% by mass, it is possible to maintain a viscosity that allows coating as a coating agent, which is preferable.

(Other resins)
Furthermore, in the raw material of the synthetic resin layer B, in addition to the (meth)acrylate oligomers such as acrylic (meth)acrylate and polyfunctional urethane acrylate, known binder resins may be used in combination without particular limitation. For example, nitrocellulose, cellulose resins such as cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB), vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl isobutyl ether copolymer resin , rosin resins, polyurethane resins, polyamide resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, vinyl chloride resins such as polyvinyl chloride resins, polyester resins, alkyd resins, ketone resins, Cyclized rubber, chlorinated rubber, butyral, petroleum resin and the like can be mentioned.
Among them, cellulose acetate butyronate (CAB) is preferred.

(Organic solvent)
An organic solvent can also be added as a diluent to facilitate the coating of the second layer.
As the organic solvent, any solvent can be used as long as it dissolves the compound having a (meth)acryloyl group to be used. More preferably, it does not contain volatile organic compounds (VOCs) at 260°C.
The purpose is to thoroughly reduce the amount of evaporation of organic solvents into the atmosphere, that is, to reduce VOCs. Aliphatic or alicyclic hydrocarbons such as methylcyclohexane and ethylcyclohexane, esters such as ethyl acetate, butyl acetate and propyl acetate, alcohols such as methanol, ethanol, isopropyl alcohol and n-butanol, acetone, methyl ethyl ketone, methyl isobutyl It is preferable not to contain any of ketones such as ketones and cyclohexanone, alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether, and ether esters such as propylene glycol monomethyl ether acetate.
These organic solvents can also be used in combination as a mixed solvent.

(Other additives)
Further, the active energy ray-curable resin composition used for the synthetic resin A layer and the synthetic resin B layer may optionally contain a polymerization inhibitor, a leveling agent, a thixotropic agent, a wax, a drying agent, and a thickening agent. agents, anti-sagging agents, plasticizers, dispersants, anti-settling agents, anti-foaming agents, UV absorbers, light stabilizers and the like.

Next, as a method for providing the second layer in the present invention, that is, a non-continuous layer in which the synthetic resin layer B having a gloss retention rate of 90% or more is evenly arranged, gravure printing and offset gravure printing are preferable, and gravure printing is particularly preferable. preferable.
After the step (2) of forming the second layer by gravure printing with a gravure plate having a dot concentration of 20% to 60%, the laminate is formed through the step (3) of curing with active energy rays in the air or in a nitrogen atmosphere. manufacture.
In the step (3) of active energy ray curing for increasing hardness and improving scratch resistance, the active energy ray may be applied either in the air or in a nitrogen atmosphere.
The total area of the second layer is 20-60% of the total area of the first layer. By setting the total area within this range, it is possible to obtain a laminate having both hardness and flexibility that ensure scratch resistance.

In addition, the laminate of the present invention can be widely used for building materials, furniture, musical instruments, office supplies, electric appliances, sporting goods, toys, daily necessities, and the like.

(Laminate manufacturing method)
Specifically, in the method for producing a laminate of the present invention, a synthetic resin layer A having a gloss retention rate of less than 70% is formed as a first layer on a base material using a printing machine or a coating machine to form a continuous layer. . The plate type at this time is not particularly specified, and known means such as an offset printing machine, a screen printing machine, etc. can be appropriately adopted, and a roll coater, gravure coater, flexo coater, air doctor coater, blade coater, air knife coater, squeeze coater can be used. , impregnation coater, transfer roll coater, kiss coater, curtain coater, cast coater, spray coater, die coater and the like may be used.
If necessary, the continuous layer is irradiated with an appropriate amount of the active energy ray to cure the first layer.
Next, a synthetic resin layer B having a gloss retention rate of 90% or more is used as a second layer to form an evenly arranged discontinuous layer using a gravure printing machine, and then an appropriate amount of active energy rays is irradiated. Cure the two layers. At this time, the active energy ray may be applied either in the atmosphere or in a nitrogen atmosphere.
By setting the total area of the second layer to be in the range of 20 to 60% of the total area of the first layer, it is possible to obtain a laminate that has both hardness and flexibility that ensure scratch resistance. can.

The present invention will be described in more detail below with reference to examples. Parts and parts by mass in the following examples represent % by mass.
The measurement of the number average molecular weight or weight average molecular weight (converted to polystyrene) by GPC in the present invention was carried out under the following conditions using an HLC8220 system manufactured by Tosoh Corporation.
Separation column: 4 TSKgelGMHHR-N manufactured by Tosoh Corporation are used.
Column temperature: 40°C.
Moving bed: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd.
Flow rate: 1.0 ml/min.
Sample concentration: 1.0% by weight.
Sample injection volume: 100 microliters.
Detector: differential refractometer.

(Adjustment Example 1: Active energy ray-curable composition 1-1)
Example 1 in Table 1, described in the first layer, acrylic acrylate (EVS-301, manufactured by DIC Corporation) 5.7 parts by mass in terms of solid content, bifunctional urethane acrylate (Luxidia 4221, DIC Corporation) company) 23.1 parts by mass, Omnirad 184 (1-hydroxycyclohexylphenyl ketone, BASF photopolymerization initiator) 1.4 parts by mass, a mixed solvent such as methyl ethyl ketone is added to make a total of 100 parts, and the active energy is sufficiently stirred. A radiation-curable composition 1-1 was prepared.
The gloss retention was 46%.

(Adjustment Example 2: Active energy ray-curable composition 1-2)
Example 3 in Table 1, 14 parts by mass of acrylic acrylate (EVS-301, manufactured by DIC Corporation) and 14.1 parts by mass of bifunctional urethane acrylate (Luxidia 4221, manufactured by DIC Corporation) for the first layer , Omnirad 184 (1-hydroxycyclohexylphenyl ketone, a photopolymerization initiator manufactured by BASF) 1.4 parts by mass, a mixed solvent such as methyl ethyl ketone was added to make a total of 100 parts, and the active energy ray-curable composition 1-2 was sufficiently stirred. was made.
The gloss retention was 62%.

(Adjustment Example 3: Active energy ray-curable composition 1-3)
Example 15 in Table 3 Bifunctional urethane acrylate (Luxidia 4221, manufactured by DIC Corporation) 28.2 parts by mass shown in the first layer, Omnirad 184 (1-hydroxycyclohexylphenyl ketone, photopolymerization initiator manufactured by BASF) ), and a mixed solvent such as methyl ethyl ketone was added to make a total of 100 parts and sufficiently stirred to prepare an active energy ray-curable composition 1-.
The gloss retention was 31%.

(Adjustment Example 4: Active energy ray-curable composition 2-1)
Example 1 in Table 1 Laromer PO9026 (colloidal silica-containing monomer, manufactured by BASF) 95.2 parts by weight, Omnirad 184 (1-hydroxycyclohexylphenyl ketone, photopolymerization initiator manufactured by BASF) shown in the second layer4. 8 parts by mass and a mixed solvent such as methyl ethyl ketone were added to make a total of 100 parts and sufficiently stirred to prepare an active energy ray-curable composition 2-1.
The gloss retention rate was 100%.

(Adjustment Examples 5 to 17: Active energy ray-curable compositions 2-2 to 2-14)
Examples 2 to 15 in Tables 1 to 3 Active energy ray-curable compositions 2-2 to 2-14 were prepared in the same manner as in Preparation Example 4 according to the formulations shown in the second layer. and the gloss retention rate was measured for each.

(Example 1: Production of laminate)
The first layer composition prepared in Preparation Example 1 was coated with a polyester film (A4100, thickness 50 μm, manufactured by Toyobo Co., Ltd.) or a primer with a bar coater (#6) using a bar coater (#8). It was applied to an unstretched polypropylene film and dried with a drier to form a first layer. Next, using an air-cooled high-pressure mercury lamp (output 120 W / cm 1 lamp) and a UV irradiation device (GS Yuasa Corporation) equipped with a belt conveyor, the coated object is placed on the conveyor and directly under the lamp (irradiation distance 15 cm) at a speed of 25 m/min to form a cured coating film of the first layer. The amount of ultraviolet irradiation was confirmed to be 55 mJ/cm using an ultraviolet integrating photometer (industrial UV checker UVR-N1 manufactured by GS Yuasa Corporation).
Subsequently, with an electric gravure printing tester GP-10 (manufactured by Kurabo Industries, Ltd.) equipped with an engraving plate (Helio 133 lines/inch, halftone dot density of 25%, 40%, and 50%), the first The second layer composition prepared in Preparation Example 1 was applied onto the cured coating film of the layer to form a discontinuous second layer. Next, UV irradiation was performed in the same manner as the first layer to form a cured coating film of the second layer, thereby producing a laminate of Example 1.

(Examples 2 and 3: Production of laminate)
Laminates 2 and 3 were produced according to the same procedure as in Example 1 by combining the active energy ray-curable compositions for the first layer and the second layer shown in Examples 2 and 3 in Table 1, respectively.

(Examples 4 to 15: Production of laminate)
In the combination of each active energy ray-curable composition for the first layer and the second layer shown in Examples 4 to 15 in Tables 2 and 3, the second layer was prepared using a gravure plate with only a halftone dot concentration of 40%. , Laminates 4 to 15 were produced according to the same procedure as in Example 1.

(Comparative Examples 1 to 5: Production of laminate)
In the combination of each active energy ray-curable composition for the first layer and the second layer shown in Table 4, the second layer was prepared in the same manner as in Example 1 using a gravure plate with only a halftone dot density of 40%. A laminate was produced according to the procedure.

After measuring the gloss retention rate of the cured films prepared from the first layer and second layer compositions of Examples 1 to 15 and Comparative Examples 1 to 5, the workability and scratch resistance of each prepared laminate were evaluated. bottom.

(Evaluation item 1: Gloss retention rate)
Regarding the first layer and second layer compositions of Examples 1 to 15 and Comparative Examples 1 to 5, the gloss retention rate at a film thickness of 10 μm was confirmed. A 10 μm coating film of each composition is formed on a polyester film using an arbitrary bar coater, dried with a dryer as necessary, and then subjected to ultraviolet irradiation in the same procedure as when producing a laminate. , to form a cured coating film. The surface of these cured coating films was subjected to 10 reciprocations with steel wool (Bonstar #0000) under a load of 1.5 kg, and the gloss retention rate was calculated. The gloss value was measured using a gloss meter ("MULTI GLOSS 268A" manufactured by Konica Minolta). The measurement conditions for the gloss value were an incident angle of 60° and a reflection angle of 60°.

Gloss retention rate (%) = (gloss value of test surface/gloss value of untested surface) x 100

(Evaluation item 2: workability)
A test piece was prepared by cutting a laminate prepared on a non-stretched polypropylene film coated with a primer with a bar coater (#6) into a width of 2 cm. The film was stretched to 300% by a tensile tester, and the surface condition of the stretched portion was visually observed and evaluated. "Crack" indicates a state in which a large crack that can be confirmed with the naked eye has occurred. "Good" refers to a state in which the surface of the laminate remains smooth.

(Evaluation item 3: scratch resistance)
Regarding the surface of the laminate produced on the polyester film, the gloss retention rate was calculated in the same manner as in "Evaluation Item 1: Gloss Retention Rate".
(Evaluation criteria)
A gloss retention rate of 70% or more is within the practical range.

Tables 1 to 4 show the compositions of the active energy ray-curable compositions of the first layer and the second layer, and the evaluation results of the produced laminates.
All numerical values in the table are parts by mass or % by mass. A blank column indicates that it is not blended.

In Tables 1-4, abbreviations indicate the following:
・EVS-301: Acrylic acrylate, manufactured by DIC Corporation ・Lucidia 4221: Bifunctional urethane acrylate, manufactured by DIC Corporation ・Omnirad184: Photopolymerization initiator 1-hydroxycyclohexylphenyl ketone, manufactured by BASF ・UN904: Poly Functional urethane acrylate, weight number average molecular weight 4900, manufactured by Negami Kogyo Co., Ltd. DPHA: mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate EOTMPTA: trimethylolpropane ethylene oxide triacrylate Laromer PO9026: contains colloidal silica Monomer, manufactured by BASF ・TEGORAD2200N: Silicon acrylate, manufactured by Evonik ・KIP-150: Photopolymerization initiator solid content 40% product 1-phenyl-2-hydroxy-2-methylpropan-1-one, manufactured by ESACURE ・HD (EO) DA: hexanediol ethylene oxide-modified diacrylate

Claims (3)

Having a first layer and a second layer in this order on the substrate,
The first layer consists of a continuous layer of synthetic resin layer A having a gloss retention rate of less than 70%,
The second layer consists of a discontinuous layer in which synthetic resin layers B having a gloss retention rate of 90% or more are evenly arranged,
A laminate, wherein the total area of the second layer is 20 to 60% of the total area of the first layer. 2. The lamination according to claim 1, wherein the synthetic resin layer B is a cured resin layer B obtained by performing active energy ray curing on a discontinuous layer uniformly arranged by gravure printing with a gravure plate having a dot concentration of 20% to 60%. body. A substrate has a first layer and a second layer in this order, the first layer is a continuous layer of synthetic resin layer A having a gloss retention rate of less than 70%, and the second layer has a gloss retention rate. A method for producing a laminate comprising discontinuous layers in which a synthetic resin layer B of 90% or more is evenly arranged, and wherein the total area of the second layer is 20 to 60% of the total area of the first layer. hand,
Step (1) of forming the first layer on the substrate with a printing machine or a coating machine;
Step (2) of forming the second layer by gravure printing with a gravure plate having a dot density of 20% to 60%;
A method for producing a laminate, characterized in that it has a step (3) of curing with active energy rays in the atmosphere or nitrogen atmosphere in this order.