WO2012023543A1 - Ink composition and decorative sheet produced using same - Google Patents

Abstract

Provided is an ink composition for use in the formation of a decorative sheet, which can impart high hardness to a decorative molded article, can also impart moldability required for forming a molded article having a more complicated shape, and enables the formation of a tuck-free hardcoat-layer-forming layer merely by thermal drying if necessary. This ink composition comprises: a polyfunctional radical-polymerizable prepolymer having at least one ionizing-radiation-curable functional group (A) selected from the group consisting of a vinyl group, a (meth)acryloyl group and an allyl group and having a weight average molecular weight of 50000 or more; reactive inorganic particles each having an ionizing-radiation-curable functional group (B) on the surface thereof; and a polyfunctional isocyanate compound.

Description

Ink composition and decorative sheet using the same

The present invention relates to an ink composition, and more specifically, imparts excellent hardness to a decorative molded product, can provide moldability capable of obtaining a molded product having a complicated shape, and has blocking resistance. The present invention relates to a decorative sheet-forming ink composition.

Conventionally, an injection molding simultaneous decorating method is used for decorating a resin molded body having a complicated surface shape such as a three-dimensional curved surface. In the injection molding simultaneous decoration method, the decorative sheet inserted into the mold at the time of injection molding is integrated with the molten injection resin injected and injected into the cavity to decorate the surface of the resin molded body It is a method of applying. In general, this method is roughly classified into an injection molding simultaneous laminate decoration method and an injection molding simultaneous transfer decoration method depending on the difference in the configuration of the decorative sheet integrated with the resin molded body.

In the injection molding simultaneous transfer decoration method, after the decorative sheet is closely attached to the inner surface of the mold and clamped, the molten injection resin is injected into the cavity to integrate the decorative sheet and the injection resin, After the decorative molded product is cooled and taken out from the mold, the decorative molded product to which the transfer layer is transferred can be obtained by peeling the base film.

The decorative molded products thus obtained include mobile PCs that can be carried everyday, for example, in recent years with the expansion of the PC market, in addition to the fields of household appliances and automobile interiors that have been used in the past. It is also attracting attention for use in the field of notebook computers, automobile exteriors, and mobile phones. In these fields, the decorative sheet is required to have surface properties such as high hardness, which are excellent in decorative molded products, and at the same time, moldability is required to obtain a molded product with a more complicated shape.

In order to satisfy such requirements, a transfer material having a protective layer using an active energy ray-curable resin composition containing a low molecular weight polymer and a polyfunctional isocyanate has been proposed (for example, Patent Document 1). However, a protective layer using such a resin composition is unlikely to be tack-free, and in order to obtain a tack-free state, baking at a high temperature of 150 ° C. or long-time heat treatment is required. Further, the above protective layer has a problem that it cannot cope with stricter demands on surface properties such as high hardness.

For the purpose of obtaining surface physical properties such as high hardness, a transfer material having a protective layer containing a low molecular weight polymer, a curing agent, and colloidal silica particles has been proposed (for example, Patent Document 2). However, this protective layer is insufficient for more stringent demands of H or higher pencil hardness, and may be blocked (set back) when the decorative sheet is wound into a roll, There is a problem that the protective layer may be whitened or a coating crack may occur for a molded product having a more complicated shape. Surface properties such as high hardness and anti-blocking and moldability are contradictory performances, and there is no decorative sheet that can realize these contradictory performances at a high level.

Japanese Patent No. 3233595 JP 2009-137219 A

Therefore, the object of the present invention is to impart excellent hardness to the decorative molded product, at the same time, to impart moldability to obtain a molded product having a more complicated shape, and to form a hard coat layer forming layer as necessary. It is to provide a decorative sheet-forming ink composition that can be tack-free only by heat drying.

Another object of the present invention is to provide a method for producing a decorative molded product using the above ink composition.

Furthermore, another object of the present invention is to provide a decorative molded product obtained by the above production method.

The ink composition according to the present invention has a polyfunctional radical having at least one ionizing radiation-curable functional group A selected from the group consisting of a vinyl group, a (meth) acryloyl group and an allyl group, and having a weight average molecular weight of 50,000 or more. It comprises a polymerizable prepolymer, reactive inorganic particles having ionizing radiation-curable functional groups B on the surface, and a polyfunctional isocyanate compound.

Moreover, the decorative sheet according to another aspect of the present invention is a decorative sheet provided with at least a release layer and a hard coat layer forming layer in this order on one side of a base film, wherein the hard coat layer forming layer is It is formed using the ink composition.

Furthermore, the method for manufacturing a decorative molded product according to another aspect of the present invention is a method for manufacturing a decorative molded product using the decorative sheet,
Arranging the decorative sheet in an injection mold;
An injection process in which molten resin is injected into the cavity of the injection mold, cooled and solidified, and the resin molded body and the decorative sheet are laminated and integrated.
A step of taking out the molded body in which the resin molded body and the decorative sheet are laminated and integrated from the injection mold,
A step of peeling the base film of the decorative sheet from the molded body, and a hard coat layer forming step of curing the hard coat layer forming layer provided on the molded body using ionizing radiation,
Is included.

In the present invention, a decorative molded product obtained by the above production method is also provided.

According to the present invention, the decorative molded product is imparted with excellent high hardness, and at the same time, it is imparted with moldability to obtain a molded product with a more complicated shape, and the hard coat layer forming layer is heat-dried as necessary. Thus, it is possible to realize an ink composition that imparts excellent production efficiency to the decorative sheet, which can be tack-free.

It is a cross-sectional schematic diagram of one Embodiment of the decorating sheet of this invention. It is a cross-sectional schematic diagram of one Embodiment of the decorative molded product of this invention.

<Ink composition>
The ink composition according to the present invention has a polyfunctional radical having at least one ionizing radiation-curable functional group A selected from the group consisting of a vinyl group, a (meth) acryloyl group and an allyl group, and having a weight average molecular weight of 50,000 or more. A polymerization type prepolymer, reactive inorganic particles having ionizing radiation-curable functional groups B on the surface, and a polyfunctional isocyanate compound are included as essential components. Hereafter, each component which comprises the ink composition by this invention is demonstrated.

<Polyfunctional radical polymerization type prepolymer having ionizing radiation curable functional group A>
In the present invention, “ionizing radiation curable” means that having an energy quantum capable of crosslinking and polymerizing a molecule in an electromagnetic wave or a charged particle beam, that is, excited by irradiation with ultraviolet rays or an electron beam to cause a polymerization reaction. It means the ability to crosslink and cure by producing. The term “ionizing radiation curable functional group” means a functional group capable of developing ionizing radiation curable, and means a functional group having an ethylenically unsaturated bond such as a vinyl group, a (meth) acryloyl group and an allyl group. It shall be.

The polyfunctional radical polymerization type prepolymer is not particularly limited as long as it is a prepolymer having an ionizing radiation curable functional group A. For example, acrylic (meth) acrylate prepolymer, urethane (meth) acrylate prepolymer, polyester Prepolymers such as (meth) acrylate-based prepolymers, epoxy (meth) acrylate-based prepolymers, and polyether (meth) acrylate-based prepolymers are preferred, and acrylic (meth) acrylate-based prepolymers are particularly preferable. In the present invention, these prepolymers may be used alone or in combination.

Here, acrylic (meth) acrylate-based prepolymers are (meth) acrylic acid alkyl ester and copolymerizable with glycidyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile, (meth) acrylic acid It is a prepolymer formed by copolymerizing a functional group-containing (meth) acrylic compound such as hydroxyalkyl or a carboxylic acid such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid.

The urethane (meth) acrylate-based prepolymer can be obtained, for example, by esterifying a polyurethane prepolymer obtained by a reaction of polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid.

As a polyester (meth) acrylate-based prepolymer, for example, by esterifying hydroxyl groups of a polyester prepolymer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid. Alternatively, it can be obtained by esterifying a terminal hydroxyl group of a prepolymer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth) acrylic acid.

The epoxy (meth) acrylate-based prepolymer can be obtained, for example, by esterifying the oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolac type epoxy resin with (meth) acrylic acid. Alternatively, a carboxyl-modified epoxy (meth) acrylate prepolymer obtained by partially modifying the epoxy (meth) acrylate prepolymer with a dibasic carboxylic acid anhydride can also be used.

The polyether (meth) acrylate polymer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid.

The weight average molecular weight of the polyfunctional radical polymerization type prepolymer described above is required to be 50,000 or more, more preferably 50,000 to 145,000, and further preferably 53,000 to 115,000. If the weight average molecular weight is within the above range, the thixotropy of the ink composition can be obtained, so that coating is easy and good moldability is also obtained. The weight average molecular weight is a value measured by gel permeation chromatography (GPC), and is a value measured under conditions using polystyrene as a standard sample.

Further, from the viewpoint of obtaining excellent surface characteristics, the double bond equivalent of the above-mentioned prepolymer is 100 to 800, preferably 150 to 500, more preferably 150 to 300. In addition, a double bond equivalent means the molecular weight per mol of ionizing radiation-curable functional groups.

<Reactive inorganic particles>
The ink composition of the present invention contains reactive inorganic particles having ionizing radiation-curable functional groups B on the surface. Preferred examples of the ionizing radiation-curable functional group B include ethylenically unsaturated bonds such as vinyl groups, (meth) acryloyl groups, and allyl groups, epoxy groups, silanol groups, and the like, which improve high hardness and scratch resistance. From these viewpoints, a vinyl group, a (meth) acryloyl group, and an allyl group are more preferable.

Preferred examples of the inorganic particles include metal oxide particles such as silica particles (such as colloidal silica, fumed silica, and precipitated silica), alumina particles, zirconia particles, titania particles, and zinc oxide particles. From the viewpoint of high hardness, silica particles and alumina particles are preferable, and silica particles are particularly preferable.

Examples of the shape of the inorganic particles include spheres, ellipsoids, polyhedrons, scales, and the like, and these shapes are preferably uniform and sized. The average particle size of the inorganic particles can be appropriately selected depending on the thickness of the layer formed from the ink composition, but is usually preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.1 μm. The average particle size is a 50% particle size (d50: median size) when particles in a solution are measured by a dynamic light scattering method and the particle size distribution is expressed as a cumulative distribution, and is a Microtrac particle size analyzer. It can be measured using Nikkiso Co., Ltd.

Among the inorganic particles described above, irregularly shaped inorganic particles are preferable from the viewpoint of high hardness. The irregular shaped inorganic particles are composed of a group of inorganic particles in which the inorganic particles are connected and aggregated having an average number of connections of 2 to 40, and are included in the inorganic particles in the present invention. Connected aggregation may be regular or irregular. As the inorganic particles forming the inorganic particle group, inorganic particles composed of metal oxides such as silica (colloidal silica, fumed silica, precipitated silica, etc.), alumina, zirconia, titania, zinc oxide, etc. are preferably mentioned, and high hardness From the viewpoint of properties, it is preferable to use irregular shaped inorganic particles made of silica or alumina. That is, the irregularly shaped inorganic particles are preferably composed of a silica particle group or an alumina particle group in which silica particles or alumina particles are linked and aggregated having an average number of connections of 2 to 40. In particular, the silica particles have an average number of connections of 2 to 40. A deformed silica particle composed of a group of linked and aggregated silica particles is preferred.

Favorable examples of the shape of the inorganic particles forming the inorganic particle group include a sphere, an ellipsoid, a polyhedron, and a scale shape. These shapes are preferably uniform and sized. The average particle diameter of the inorganic particles forming the inorganic particle group is preferably 0.005 to 0.5 μm, and more preferably 0.01 to 0.1 μm. The average particle size of the irregularly shaped inorganic particles can be appropriately selected depending on the thickness of the layer formed from the ink composition, but is usually preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.1 μm. . In addition, the average particle diameter here is measured by the same method as the average particle diameter of the above-described inorganic particles.

The reactive inorganic particles are preferably reactive silica particles or reactive irregularly shaped silica particles having ionizing radiation-curable functional groups B on the surface of the silica particles or irregularly shaped silica particles as described above, and are surface-decorated with a silane coupling agent. Are preferred.

Preferred examples of the silane coupling agent include known silane coupling agents having a vinyl group, an epoxy group, a (meth) acryloyl group, an allyl group, and the like. More specifically, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyldimethylmethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyldimethylethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropyl Dimethylmethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldiethoxysilane, γ-acryloxypropyldimethylethoxysilane, vinyltriethoxysilane, γ-glycid Xylpropyltrimethoxysilane and the like are preferred. Among these, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyldimethylmethoxysilane are more preferable.

The method for decorating the surface of inorganic particles with a silane coupling agent is not particularly limited, and a known method can be adopted. For example, a dry method in which a silane coupling agent is sprayed, a wet method in which inorganic particles are dispersed in a solvent, and then a silane coupling agent is added and reacted can be used.

<Polyfunctional isocyanate compound>
The ink composition of the present invention contains a polyfunctional isocyanate compound having two or more isocyanate groups. Examples of the polyfunctional isocyanate include aromatic isocyanates such as 2,4-tolylene diisocyanate (TDI), xylene diisocyanate (XDI), naphthalene diisocyanate, 4,4-diphenylmethane diisocyanate, or 1,6-hexamethylene diisocyanate ( And polyisocyanates such as aliphatic (or alicyclic) isocyanates such as HMDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Further, adducts or multimers of these various isocyanates, for example, tolylene diisocyanate adducts, tolylene diisocyanate trimers, blocked isocyanate compounds, and the like may be used.

In the present invention, among the polyfunctional isocyanate compounds, those having at least one ionizing radiation-curable functional group C selected from the group consisting of vinyl group, (meth) acryloyl group, allyl group and epoxy group are high. Particularly preferred from the viewpoint of hardness. Specifically, a polyfunctional isocyanate compound having at least one functional group having an ethylenically unsaturated bond and two or more isocyanate groups is preferable, such as “Laromer LR9000 (trade name)” (manufactured by BASF). .

<Solvent>
In addition to the above-described components, the ink composition of the present invention may contain a solvent for the purpose of adjusting the viscosity. Solvents include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, isopropyl alcohol, butanol, isobutyl alcohol, methyl glycol, methyl glycol acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve; acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketone, cyclohexanone, diacetone alcohol; esters such as methyl formate, methyl acetate, ethyl acetate, ethyl lactate, butyl acetate; nitrogen-containing compounds such as nitromethane, N-methylpyrrolidone, N, N-dimethylformamide; Ethers such as propylene glycol monomethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, dioxolane; methylene chloride, chloroform Preferred are halogenated hydrocarbons such as chloromethane, trichloroethane and tetrachloroethane; other substances such as dimethyl sulfoxide and propylene carbonate; or a mixture thereof. More preferred solvents include methyl ethyl ketone and methyl isobutyl ketone.

The amount of the solvent in the ink composition may be appropriately selected according to the viscosity of the composition, but the solid content of the prepolymer combined with the reactive inorganic particles and other photopolymerization initiators described later. The amount is usually about 10 to 70% by mass, preferably 20 to 50% by mass.

<Photopolymerization initiator>
The ink composition of the present invention may contain a photopolymerization initiator. Examples of the photopolymerization initiator include acetophenone series, ketone series, benzophenone series, benzoin series, ketal series, anthraquinone series, disulfide series, thioxanthone series, thiuram series, and fluoroamine series. Of these, acetophenone, ketone, and benzophenone are preferred. These photopolymerization initiators may be used alone or in combination of two or more.

The content of the photopolymerization initiator is preferably about 0.5 to 10 parts by mass with respect to 100 parts by mass of the solid content of the prepolymer, more preferably 1 to 8 parts by mass, and still more preferably 3 to 8 parts by mass.

<Other ingredients>
The ink composition of the present invention may contain various additives depending on the desired physical properties to be obtained. Examples of additives include ultraviolet absorbers, infrared absorbers, light stabilizers, polymerization inhibitors, crosslinking agents, antistatic agents, antioxidants, leveling agents, thixotropic agents, coupling agents, plasticizers, and extinguishing agents. Examples include foaming agents, fillers, thermal radical generators, and aluminum chelating agents.

In addition, the ink composition of the present invention may be a polymer such as an acrylic resin, a cellulose resin, a urethane resin, a polyester resin, an epoxy resin, a vinyl group, or a (meth) acryloyl group as long as the effect is not impaired. , Monomers having at least one ionizing radiation-curable functional group selected from the group consisting of allyl groups and epoxy groups, such as urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and polyether (meth) A reactive monomer such as polyfunctional (meth) acrylate such as acrylate may be included.

The solid content of the prepolymer in the ink composition is preferably 95% by mass or less, more preferably 85% by mass or less, based on the total of the solid content of the prepolymer and the reactive inorganic particles. Especially preferably, it is 70 mass% or less. Moreover, as a range of the minimum of content of the solid content of a prepolymer, 30 mass% or more is preferable, More preferably, it is 40 mass% or more, Most preferably, it is 50 mass% or more. If the content of the prepolymer is within the above range, when forming the hard coat layer forming layer using the ink composition, the hard coat layer forming layer formed by applying the ink composition on the release layer is It becomes tack-free just by heat drying if necessary. As a result, even if the sheet is wound up in a roll shape without performing a semi-curing treatment by irradiation with ionizing radiation or high-temperature baking, no blocking (back-off) occurs. In addition, since the need for the semi-curing treatment is eliminated, even when deep drawing is performed such that the area ratio of the decorative sheet before and after molding becomes 130% or more when formed, cracks and whitening occur in the maximum stretched portion. It is possible to form a hard coat forming layer that can satisfactorily follow the shape of the mold without occurring. Furthermore, excellent high hardness can be obtained by curing the hard coat forming layer using ionizing radiation after molding transfer.

The solid content of the polyfunctional isocyanate compound in the ink composition is preferably 1 to 30 parts by weight, more preferably 1 to 20 parts by weight, and more preferably 3 to 30 parts by weight with respect to 100 parts by weight of the solid content of the prepolymer. 15 parts by mass is more preferable. When the content of the solid content of the polyfunctional isocyanate compound is within the above range, heat resistance during molding can be obtained while maintaining excellent high hardness and moldability.

<Decoration sheet>
The decorative sheet according to the present invention comprises at least a release layer and a hard coat layer forming layer on one side of a base film in order, and the hard coat layer forming layer is formed using the ink composition described above. Is. Hereinafter, the decorative sheet of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view of a preferred embodiment of the decorative sheet of the present invention. FIG. 2 is a schematic cross-sectional view of a preferred embodiment of the decorative molded product of the present invention.

As shown in FIG. 1, the decorative sheet 10 according to the present invention has a release layer 12, a hard coat layer forming layer 13, an anchor layer 14, a picture layer 15 and a pattern layer 15 on one surface of a base film 11 made of a polyester film. The adhesive layer 16 is laminated in order, and the antistatic layer 19 is laminated on the other surface of the base film 11 (the surface opposite to the surface on which the release layer 11 is provided).

Further, as shown in FIG. 2, the decorative molded product 20 according to the present invention is obtained by curing the adhesive layer 16, the pattern layer 15, the anchor layer 14, and the hard coat layer forming layer 13 on the surface of the resin molded body 21. The hard coat layer 22 is sequentially laminated. Hereinafter, it demonstrates in each member which comprises a decorating sheet and a decorative molded product.

<Base film>
Examples of the base film include polyolefin resins such as polyethylene and polypropylene; polyvinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl acetate copolymer, and ethylene / vinyl alcohol copolymer; polyethylene terephthalate, Polyester resins such as polybutylene terephthalate; Acrylic resins such as poly (meth) acrylate methyl and poly (meth) ethyl acrylate; Styrene resins such as polystyrene, acrylonitrile / butadiene / styrene copolymers, cellulose triacetate, Cellophane, polycarbonate, polyurethane-based elastomeric resins, etc. are used. Of these, polyester resins, particularly polyethylene terephthalate (hereinafter referred to as “PET”) are preferred from the viewpoint of good moldability and releasability.

The thickness of the base film is preferably in the range of 25 to 150 μm, more preferably in the range of 25 to 75 μm, from the viewpoints of moldability, shape followability and easy handling.

<Release layer 12>
The release layer 12 is a layer provided for easily peeling the transfer layer 17 formed by sequentially laminating the hard coat layer forming layer 13, the anchor layer 14, the pattern layer 15, and the adhesive layer 16 from the base material sheet 11. . By providing the release layer 12, the transfer layer 17 is reliably and easily transferred from the decorative sheet according to the present invention to the transfer target, and is provided as necessary, the base film 11, the release layer 12, and the like. The release layer 18 made of the antistatic layer 19 can be reliably peeled off.

For the release layer 12, melamine resin release agent, silicone resin release agent, fluororesin release agent, cellulose resin release agent, urea resin release agent, polyolefin resin release agent, paraffin A mold release agent such as a system mold release agent, an acrylic resin mold release agent, or a composite mold release agent thereof is preferably used. Among these, from the viewpoint of making the peel strength between the release layer and the hard coat layer forming layer within a predetermined range and reliably peeling the release layer 18, a melamine resin release agent and an acrylic resin release agent, or A composite of these such as acrylic-melamine is preferred.

When using a melamine resin release agent, it is preferable to use an acid catalyst in order to accelerate the curing of the release agent. The acid catalyst is not particularly limited, and preferable examples include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid. The amount of the acid catalyst used is preferably about 0.05 to 3%, more preferably 0.05 to 1%, based on the solid content of the melamine resin contained in the melamine resin release agent. In order to accelerate the curing of the release agent, it is preferable to perform a heat treatment at 130 to 170 ° C. for about 30 seconds to 2 minutes.

The release layer 12 is formed by applying an ink prepared by dissolving or dispersing the above-described additive added to a release agent in an appropriate solvent onto the base sheet 11 by a known means.・ Can be dried. The thickness of the release layer is preferably about 0.1 to 5 μm.

<Hard coat layer forming layer>
The hard coat layer forming layer is a layer formed using the above-described ink composition, and becomes a hard coat layer 22 in the decorative molded product 20 by being cured. The hard coat layer 22 is an outermost layer of the decorative molded product, and is a layer for protecting the molded product and the picture layer from abrasion and chemicals. Therefore, the hard coat layer forming layer 13 is a layer having the performance of being excellent in surface physical properties such as chemical resistance and contamination resistance as well as excellent high hardness and scratch resistance by being cured. Cost.

The hard coat layer forming layer is formed by coating the ink composition described above by a gravure coating method, a roll coating method, a comma coating method, a coating method such as a die coating method, a gravure printing method, a screen printing method, or the like. be able to.

The thickness of the hard coat layer forming layer is preferably in the range of 0.5 to 30 μm, more preferably 3 to 15 μm. When the thickness is in the above range, not only excellent high hardness and scratch resistance, but also surface properties such as chemical resistance and stain resistance are obtained, and at the same time, excellent moldability and shape followability are obtained. Obtainable. It is also advantageous in terms of material costs.

<Anchor layer>
The anchor layer 14 is a layer provided as desired in order to improve the adhesion between the hard coat layer forming layer 13 and the adhesive layer 16 or the pattern layer 15 when there is the pattern layer 15. Anchor layer is a two-component cured urethane resin, thermosetting urethane resin, melamine resin, cellulose ester resin, chlorine-containing rubber resin, chlorine-containing vinyl resin, acrylic resin, epoxy resin, vinyl copolymer It can be formed of resin or the like. For example, these resins are applied and formed on the hard coat layer forming layer 13 by a coating method such as a gravure coating method, a roll coating method, or a comma coating method, a gravure printing method, a screen printing method, or the like. be able to. The thickness of the anchor layer 14 is usually about 0.1 to 5 μm, preferably about 1 to 5 μm.

<Pattern layer>
The pattern layer 15 is a layer for imparting a desired design to the decorative molded product, and is a layer provided as desired. Although the pattern of the pattern layer 15 is arbitrary, for example, a pattern composed of wood grain, stone pattern, cloth pattern, sand pattern, geometric pattern, character, and the like can be mentioned. Further, the pattern layer 15 can be provided with a pattern pattern layer that expresses the above-mentioned pattern and a solid surface layer alone or in combination, and the full surface solid layer is usually used as a concealment layer, a colored layer, a colored concealment layer, or the like. .

The pattern layer 15 is usually a polyvinyl resin, a polyester resin, an acrylic resin, a polyvinyl acetal resin, a cellulosic resin on the hard coat layer forming layer 13 or the anchor layer 14 formed as described above. It is formed by printing with a printing ink containing a resin such as a resin as a binder and an appropriate color pigment or dye as a colorant. Examples of the printing method include known printing methods such as gravure printing, offset printing, silk screen printing, transfer printing from a transfer sheet, sublimation transfer printing, and ink jet printing. The thickness of the pattern layer 15 is preferably 5 to 40 μm and more preferably 5 to 30 μm from the viewpoint of design.

<Adhesive layer>
The adhesive layer 16 is a layer formed to transfer the transfer layer 17 to the resin molded body with good adhesiveness. For the adhesive layer 16, a heat-sensitive or pressure-sensitive resin suitable for the material of the resin molded body is appropriately used. For example, when the material of the resin molding is an acrylic resin, it is preferable to use an acrylic resin. If the resin molding is made of polyphenylene oxide / polystyrene resin, polycarbonate resin, or styrene resin, use an acrylic resin, polystyrene resin, polyamide resin, or the like that has an affinity for these resins. Is preferred. Further, when the material of the resin molding is a polypropylene resin, it is preferable to use a chlorinated polyolefin resin, a chlorinated ethylene-vinyl acetate copolymer resin, a cyclized rubber, or a coumarone indene resin.

Examples of the method for forming the adhesive layer 16 include a coating method such as a gravure coating method and a roll coating method, a printing method such as a gravure printing method and a screen printing method. In addition, when the pattern layer 15 has sufficient adhesiveness with respect to a resin molding, the contact bonding layer 16 does not need to be provided. The thickness of the adhesive layer 16 is usually preferably about 0.1 to 5 μm.

<Antistatic layer>
The decorative sheet according to the present invention may include an antistatic layer. The antistatic layer 19 is a layer that is preferably provided in order to prevent foreign matter from adhering to the decorative sheet, and is provided on the surface of the base film 11 opposite to the surface on which the release layer is provided.

Antistatic agents used for the antistatic layer include anionic surfactants such as carboxylic acid, sulfonic acid, and phosphoric acid; cationic surfactants such as quaternary ammonium; alkylbetaine, alkylimidazoline , Amphoteric surfactants such as alkylalanine; nonionic surfactants such as alkylene oxide polymers, alkylene oxide copolymers, aliphatic alcohol-alkylene oxide adducts; carbon, gold, platinum, silver, copper, Inorganic conductive materials such as various metal powders such as aluminum, nickel, titanium and molybdenum; polyacetylene, polypyrrole, polyparaphenylene, polyaniline, polythiophene, polyphenylene vinylene, polyvinylcarbazole, or aminocarboxylic acid, dicarboxylic acid and polyethylene A conductive polymer such as polyether ester amide resin consisting of recall may be preferably mentioned.

The antistatic layer is formed by applying a coating composed of the above-described antistatic agent and an organic solvent by a coating method such as a gravure coating method or a roll coating method, or a printing method such as a gravure printing method or a screen printing method. . The thickness of the antistatic layer thus formed is usually preferably 0.1 to 5 μm. If the thickness of the antistatic layer is within the above range, excellent antistatic performance can be obtained efficiently.

The decorative sheet according to the present invention is excellent in manufacturing efficiency because it is tack-free as long as the hard coat layer forming layer is heat-dried as necessary, and therefore has excellent blocking resistance and at the same time heat resistance. Moreover, since it is not necessary to perform a semi-curing treatment by irradiation with ionizing radiation or high-temperature baking in order to make it tack-free, it has excellent moldability and shape followability. Furthermore, excellent high hardness and scratch resistance can be obtained by curing the hard coat layer forming layer using ionizing radiation after molding transfer. For these reasons, it can be used in a wide range of fields such as household electrical appliances and automobile interior parts, personal computer fields, especially personal computer housings.

<Manufacturing method of decorative molded product>
The method for producing a decorative molded product according to the present invention includes a step of arranging the decorative sheet in an injection mold (first step), injecting a molten resin into the cavity of the injection mold, and cooling and solidifying. Then, an injection process (second process) in which the resin molded body and the decorative sheet are laminated and integrated, and a molded body in which the resin molded body and the decorative sheet are stacked and integrated is taken out from the injection mold. The step (third step), the step of peeling the base film of the decorative sheet from the molded body (fourth step), and the hard coat layer forming layer provided on the molded body are cured using ionizing radiation. A hard coat layer forming step (fifth step). Hereinafter, each step will be described.

<First step>
The first step is a step of placing the above-mentioned decorative sheet in a molding die and sandwiching it. Specifically, the decorative sheet is placed in a molding die composed of a movable mold and a fixed mold with the transfer layer 17 inside, that is, the base film 11 is on the fixed mold side. Send it in. At this time, a single sheet of decorative sheet may be fed one by one, or a necessary part of a long decorative sheet may be intermittently fed.

When placing the decorative sheet in the molding die, (i) simply heat the die and place it so as to adhere to the die by vacuum suction, or (ii) place a heating plate from the transfer layer 17 side. It can be heated and softened, preliminarily molded so that the decorative sheet follows the shape in the mold, and clamped so as to be in close contact with the inner surface of the mold. The heating temperature at (ii) is preferably in the range of near the glass transition temperature of the substrate film 11 and less than the melting temperature (or melting point), and is usually performed at a temperature near the glass transition temperature. The vicinity of the glass transition temperature is a range of about ± 5 ° C. glass transition temperature, and generally about 70 to 130 ° C. In the case of (ii), vacuuming can also be performed when the decorative sheet is heated and softened with a hot plate for the purpose of bringing the decorative sheet into close contact with the surface of the molding die.

<Second step>
The second step is an injection step in which the molten resin is injected into the cavity, cooled and solidified, and the resin molded body and the decorative sheet are laminated and integrated. When the injection resin is a thermoplastic resin, it is made into a fluid state by heating and melting. When the injection resin is a thermosetting resin, the uncured liquid composition is appropriately heated and injected in a fluid state, and then cooled. And solidify. As a result, the decorative sheet is integrally attached to the formed resin molded body, and becomes a decorative molded product. The heating temperature of the injection resin depends on the injection resin, but is generally about 180 to 280 ° C.

The injection resin used for the decorative molded product may be any thermoplastic resin that can be injection-molded or a thermosetting resin (including a two-component curable resin), and various resins can be used. Examples of such thermoplastic resin materials include polystyrene resins, polyolefin resins, ABS resins (including heat-resistant ABS resins), AS resins, AN resins, polyphenylene oxide resins, polycarbonate resins, polyacetal resins, and acrylic resins. Examples thereof include resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polysulfone resins, and polyphenylene sulfide resins. Examples of the thermosetting resin include a two-component reaction curable polyurethane resin and an epoxy resin. These resins may be used alone or in combination of two or more.

<Third step and fourth step>
The third step is a step of taking out a molded body in which the decorative sheet and the resin molded body are integrated, and the fourth step is a step of peeling the base film of the decorative sheet from the molded body. Since the base film 11 has the release layer 12, at the boundary surface between the release layer 12 and the hard coat layer forming layer 13, the base film 11 and the release layer 12, and if necessary. The release layer 18 including the antistatic layer 19 provided can be easily peeled from the decorative molded product 20. In this way, a molded product is obtained in which the adhesive layer 16, the pattern layer 15, the anchor layer 14, and the hard coat layer forming layer 13 are sequentially laminated on the surface of the resin molded body 21.

<5th process>
The fifth step is a step of forming a hard coat layer by curing the hard coat layer forming layer 13 in the molded product obtained in the fourth step using ionizing radiation. The curing in the fifth step can be performed by irradiating with ionizing radiation in an atmosphere having an oxygen concentration of 2% or less. By performing the curing in this manner, it is possible to obtain further excellent high hardness and scratch resistance.

An atmosphere having an oxygen concentration of 2% or less can be obtained by a method such as nitrogen, argon, hydrogen, etc., preferably using nitrogen, or by performing air suction so that the oxygen concentration is about 2% or less.

The hard coat layer forming layer 13 can be cured by irradiation with ionizing radiation such as an electron beam and ultraviolet rays. When an electron beam is used as the ionizing radiation, the accelerating voltage can be appropriately selected according to the type of prepolymer or monomer used or the thickness of the hard coat layer forming layer 13, but usually an accelerating voltage of about 70 to 300 kV is preferable. . The irradiation dose is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad). The electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

When ultraviolet rays are used as ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted, and the irradiation dose is about 500 to 1500 mJ. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used.

The decorative molded product according to the present invention thus obtained has excellent high hardness and excellent surface properties such as chemical resistance and stain resistance. In addition, by using the decorative sheet of the present invention that provides moldability that can correspond to a molded product having a more complicated shape, a decorative molded product that is excellent in finish can be obtained.

The decorative molded product according to the present invention can be suitably used in a wide range of fields such as household appliances and automobile interior parts, personal computer field, especially personal computer casing, taking advantage of these excellent characteristics. Can do. *

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the evaluation method of the Example was performed as follows.

1. Preparation of test sample On substrate film (“F99 (product number)”, thickness: 50 μm, manufactured by Toray Industries, Inc.), melamine resin mold release agent (melamine resin solid content ratio 0.5% acid catalyst (para Toluene sulfonic acid) is added) and the release layer is formed by gravure printing at a coating amount of 2 g / m 2 and heat-treated in an oven at 150 ° C. for 60 seconds, and the ink used in each of the examples and comparative examples. The composition was applied with a bar coater and dried in an oven at 100 ° C. for 60 seconds to obtain a test sample. Here, the coating amount of the ink composition was such that the thickness of the dried ink coating layer was 6 g / m2.

2. Evaluation of blocking resistance (sheet roll-up ability) The PET film used for the preparation of the test sample was superimposed on the ink coating layer surface of the test sample, and an ink blocking tester (“DG-BT (model number)”, Daiwa Gravure Co., Ltd.) Was used for 12 hours in an oven at 40 ° C. while applying a load of 1 kg / cm 2. Then, the test sample was taken out and the superimposed PET film was peeled off. The removal (inversion) of the ink coating layer on the peeled PET film was evaluated according to the following criteria.
A: There was no set-up at all B: There was some set-up, but there was no problem in practical use C: Set-up was remarkable

3. Evaluation of high hardness After a test sample is cured by the curing method in each of the examples and comparative examples, a pencil scratch coating film hardness tester (“D-NP” (model number) is used according to JIS K5600-5-4. ) ”, Manufactured by Toyo Seiki Seisakusho Co., Ltd.), and a pencil scratch test pencil (manufactured by Mitsubishi Pencil Co., Ltd.). The test of scratching the ink coating layer with a pencil of each hardness was conducted 5 times, and the pencil hardness of which the scar did not occur 3 times or more was defined as the pencil hardness of the test sample.

Synthesis Example 1 (Synthesis of Prepolymer 1)
A 2 L four-necked flask equipped with a condenser, dropping funnel and thermometer was charged with 120 g of methyl isobutyl ketone (MIBK) and 210 g of methyl ethyl ketone (MEK). The four-necked flask was charged with 80 g of glycidyl methacrylate (GMA), methyl methacrylate ( MMA) 20 g and a mixture of azo initiator (azobisisobutyronitrile, AIBN-1) 0.75 g were added dropwise over 2 hours with a dropping funnel over 2 hours at a temperature of 100 to 110 ° C. After the reaction, 0.6 g of an azo initiator (azobisisobutyronitrile, AIBN-2) was further added, and the mixture was kept warm for 3 hours and then cooled to room temperature. To this, a mixed solution consisting of 40.6 g of acrylic acid (AA), 2 g of triphenylphosphine, and 0.5 g of methoquinone was added to carry out an addition reaction. The neutralization titration of the potassium hydroxide solution confirmed the disappearance of the acid value of the reactive organism, and the reaction was terminated.

The weight average molecular weight of the obtained reaction product (prepolymer 1) was 80,000, the double bond equivalent was 250 g / mol (calculated value), and the solid content was 30%. The weight average molecular weight is a value measured by gel permeation chromatography (GPC), and is a value measured under conditions using polystyrene as a standard sample.

Synthesis Example 2 (Synthesis of Prepolymer 2)
In Synthesis Example 1 (Synthesis of Prepolymer 1), Prepolymer 2 was synthesized in the same manner as in Synthesis Example 1 except that the amount of the agent used was changed to the amount shown in Table 1. Table 1 shows the weight average molecular weight, double bond equivalent, and resin solid content of the resulting prepolymer 2. In addition, the numerical value of the compounding composition column in a table | surface is all gram.

Example 1
(1) Manufacture of a decorative sheet On a base film (“F99 (product number)”, thickness: 50 μm, manufactured by Toray Industries, Inc.), a coating liquid (“Melan 265” (product number) containing melamine resin as a main component. ), Manufactured by Hitachi Chemical Co., Ltd., isobutyl alcohol-modified melamine resin) at a coating amount of 2 g / m ² to form a release layer, and the ink composition shown below was applied at a coating amount of 6 g / m ^2. The hard coat layer forming layer was formed by gravure printing.
Ink composition:
Prepolymer 1: 20.0 parts by mass (solid content: 6 parts by mass), acrylic acrylate prepolymer (prepolymer synthesized in Synthesis Example 1, molecular weight: 80000, double bond equivalent: 250 g / mol)
Reactive deformed silica particles: 10 parts by mass (solid content 4 parts by weight), ("ELCOM V-8803 (product number)", manufactured by JGC Catalysts & Chemicals, Inc., reactive deformed silica particles, average number of connections: 2 to regularly 10 particles, average particle size of irregularly shaped inorganic particles; 25 nm)
Reactive polyfunctional isocyanate: 1 part by mass (solid content 1 part by mass), ("Laromer LR9000 (product number)", manufactured by BASF)
Photopolymerization initiator: 0.4 parts by mass (“IRGACURE 184 (product number)”, manufactured by Ciba Japan, 1-hydroxycyclohexyl phenyl ketone)
Solvent: 6.7 parts by mass, mixed solvent of methyl ethyl ketone and methyl isobutyl ketone (blending ratio 70:30)

Next, an anchor layer is formed by gravure printing with a coating containing acrylic resin as a main component at a coating amount of 4 g / m ² , and then a gravure printing is performed with an acrylic printing ink at a coating amount of 8 g / m ^2. Then, a pattern layer was formed, and an acrylic coating solution was applied at a thickness of 4 μm to form an adhesive layer. Furthermore, a coating liquid (cationic surfactant: quaternary ammonium salt) containing a cationic surfactant as a main component is applied to the surface of the base film opposite to the surface provided with the release layer. Gravure printing was performed at an amount of 1 g / m ² to form an antistatic layer, and a decorative sheet of Example 1 was obtained. Further, using the ink composition used in Example 1, the above 1. A test sample was prepared based on the preparation of the test sample, and evaluation of blocking resistance (sheet winding suitability) and high hardness were performed. The evaluation results were as shown in Table 2 below.

(2) Production of decorative molded product The decorative sheet obtained above was sucked into a mold heated to 70 ° C. and adhered to the inner surface of the mold. The mold used was of a shape with a high degree of deep drawing, having a 80 mm square size, a 10 mm rise and a 3R tray shape.

On the other hand, ABS resin (“Crustic MTH-2 (product number)”, manufactured by Nippon A & L Co., Ltd.) was used as the injection resin, and this was melted at 230 ° C. and then injected into the cavity. After cooling and taking out from the mold, the base film was peeled off to obtain a molded product having an adhesive layer, a printed layer, an anchor layer, and a hard coat layer forming layer in this order on the surface of the resin molded product. Further, using an output variable type UV lamp system (“DRS-10 / 12QN (model number)”, manufactured by Fusion UV Systems Japan Co., Ltd.) in an air atmosphere, the molded product is irradiated with ultraviolet rays at an irradiation dose of 1000 mJ. Then, the hard coat layer forming layer was cured to obtain a resin molded product of Example 1 as a hard coat layer.

4). Evaluation of Appearance (Moldability) The resulting resin molded product was evaluated for appearance (moldability) according to the following criteria.
A: Paint cracks and whitening were not confirmed at all in the hard coat layer (and its formation layer), and followed the shape of the mold well. B: Slight paint cracks and slight defects in the hard coat layer (and its formation layer) C: whitening confirmed C: Some coating cracks and slight whitening were confirmed in the hard coat layer (and its formation layer), but no problem in practical use D: Significant coating crack in the hard coat layer (and its formation layer) The results of the evaluation that confirmed whitening and whitening were as shown in Table 2 below.

5. Evaluation of Appearance (Heat Resistance) Further, the appearance (heat resistance) around the gate part (resin injection part) of the obtained resin molded product was evaluated according to the following criteria.
A: Deformation or whitening due to flow was not confirmed at all in the hard coat layer (and its formation layer) B: Deformation or slight whitening due to slight flow was confirmed in the hard coat layer (and its formation layer) C: Deformation and slight whitening due to slight flow were confirmed in the hard coat layer (and its formation layer), but there was no practical problem. D: Deformation and whitening due to significant flow were confirmed in the hard coat layer (and its formation layer). The evaluation results were as shown in Table 2 below.

Examples 2, 3 and Comparative Examples 1-7
In Example 1, decorative sheets and decorative molded articles of Examples 2 and 3 and Comparative Examples 1 to 7 were obtained in the same manner as Example 1 except that the ink composition is shown in Table 2. About the used ink composition, evaluation of said blocking resistance (sheet winding suitability) and evaluation of high hardness were performed, and said external appearance evaluation was performed about the obtained decorative molded product. The evaluation results were as shown in Table 2 below.

* 1, Prepolymer synthesized in Synthesis Example 1.
* 2. Prepolymer synthesized in Synthesis Example 2.
* 3, unreactive colloidal silica particles ("MEK-ST-L (product number)", manufactured by Nissan Chemical Industries, Ltd., average particle diameter d50: 40 nm)
* 4 Polyfunctional isocyanate: “Coronate HX (product number)” manufactured by Nippon Polyurethane Industry Co., Ltd. * 5 The amount of the solvent is the amount of the solvent added and the “ELCOM V-” used as the prepolymer and reactive inorganic particles. 8803 (product number) ”.
* 6 Content of prepolymer solids (% by mass) relative to the total of prepolymer solids and reactive inorganic particles.
* 7, Prepolymer, reactive inorganic particles, (reactive) polyfunctional isocyanate, photopolymerization initiator and prepolymer solids relative to the total of solvent, solvent, reactive inorganic particles, (reactive) polyfunctional isocyanate and photopolymerization initiator Is the total content (mass%).

DESCRIPTION OF SYMBOLS 10 Decorating sheet 11 Base film 12 Release layer 13 Hard coat layer forming layer 14 Anchor layer 15 Picture layer 16 Adhesive layer 17 Transfer layer 18 Peeling layer 19 Antistatic layer 20 Decorated molded body 21 Resin molded body 22 Hard coat layer

Claims (8)

1. A polyfunctional radical polymerizable prepolymer having at least one ionizing radiation curable functional group A selected from the group consisting of a vinyl group, a (meth) acryloyl group and an allyl group, having a weight average molecular weight of 50,000 or more, An ink composition comprising reactive inorganic particles having an ionizing radiation-curable functional group B and a polyfunctional isocyanate compound.
2. The ink composition according to claim 1, wherein the reactive inorganic particles are reactive silica particles and / or reactive irregularly shaped silica particles.
3. The ink composition according to claim 1 or 2, wherein the polyfunctional radical polymerization type prepolymer is an acrylic (meth) acrylate prepolymer.
4. The polyfunctional isocyanate compound has at least one ionizing radiation-curable functional group C selected from the group consisting of a vinyl group, a (meth) acryloyl group, an allyl group, and an epoxy group. 2. Ink composition as described in above.
5. The ink according to any one of claims 1 to 4, wherein the decorative film comprises at least a release layer and a hard coat layer forming layer in order on one side of the base film, wherein the hard coat layer forming layer is the ink. A decorative sheet that is formed using the composition.
6. The decorative sheet according to claim 5, wherein an antistatic layer is provided on the surface of the base film opposite to the surface on which the release layer is provided.
7. A method for producing a decorative molded product using the decorative sheet according to claim 5 or 6,
   Arranging the decorative sheet in an injection mold;
   An injection process in which molten resin is injected into the cavity of the injection mold, cooled and solidified, and the resin molded body and the decorative sheet are laminated and integrated.
   A step of taking out the molded body in which the resin molded body and the decorative sheet are laminated and integrated from the injection mold,
   A step of peeling the base film of the decorative sheet from the molded body, and a hard coat layer forming step of curing the hard coat layer forming layer provided on the molded body using ionizing radiation,
   Comprising a method.
8. A decorative molded product obtained by the production method according to claim 7.

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