JP2005162868A - Resin composition for use in protective layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin composition for use in a protective layer capable of forming the protective layer having excellent transparency, resistance to a plasticizer and abrasion resistance on an image. <P>SOLUTION: This resin composition is used for the protective layer to protect the image, and comprises a layer silicate of 0.1-100 pts.wt. based on an amount of the resin of 100 pts.wt. and having total light transmission of ≥65% measured by a method based on JIS K 7105 when molded into a film of thickness of 1mm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a protective layer resin composition capable of forming a protective layer having excellent chemical resistance, plasticizer resistance and durability on an image.

As a printing method for forming an image, for example, a heat-sensitive sublimation transfer method in which a dye in a color material layer is sublimated and diffused by heat and the dye is transferred to an image receiving sheet. A color material layer is melted and softened by heating. A thermal melt transfer type, an ink jet type, an electrophotographic type, etc., which are transferred onto the image receiving sheet are widely used. Among them, thermal transfer recording methods such as thermal sublimation transfer method and thermal fusion transfer method are
Since various images can be easily formed, it is widely used, for example, for creation of ID cards, business photographs, printed materials with a relatively small number of printed sheets such as printers and video printers of personal computers.

The thermal sublimation transfer method can control the amount of dye transfer in dot units by the amount of energy applied to the thermal transfer sheet, so it is excellent in forming a gradation image, but the formed image is different from that of ordinary printing ink. The coloring material is not a pigment but a relatively low molecular weight dye and has no vehicle, so that it has a problem in that it is inferior in durability such as light resistance, weather resistance, and abrasion resistance. It was. In addition, there is a problem that it is inferior in chemical resistance and solvent resistance with respect to a solution of alcohol or the like that is routinely used in general households. Furthermore, when it comes into contact with a card case, a file sheet, a plastic eraser or the like containing a plasticizer, there is also a problem that the plasticizer resistance is inferior such that an image is blurred or a dye is transferred to a contact object.

As a means for solving such problems, for example, there is a method of forming a protective layer made of a resin composition on the formed image. Examples of the method for forming the protective layer include a method of laminating a molded film, a method of pouching, and a method of transferring the protective layer with the same thermal head as the image formation at the time of image formation. However, even if a protective layer made of such a resin composition is provided, the protective layer itself is inferior in plasticizer resistance, so that it is insufficient to solve the problem of plasticizer resistance in images. In particular, if a printed material having a protective layer thermally transferred to an image-receiving sheet on which an image is formed is stored in contact with a card case containing a plasticizer, a file sheet, a plastic eraser, etc., an image of the printed material is formed. The dye that has been transferred to the contacted object side contaminates the card case, etc., the density of the printed material decreases, or the printed material adheres to the contact surface of the card case containing the plasticizer. There is a problem that the image is destroyed when the printed matter is taken out from the printer.

Therefore, a method is known in which when a protective layer is used to protect an image, a thermoplastic resin having excellent plasticizer resistance is used as a binder to improve the plasticizer resistance performance. However, such a method has a problem in terms of wear resistance (scratch resistance), such as a scratch on the protective layer when the surface of the protective layer becomes soft and is scratched with a nail. .
In addition, for the purpose of improving the performance of both abrasion resistance and plasticizer resistance, a method of using an electron beam curable resin or a thermosetting resin as a binder and adding a filler is known, Since a special drying apparatus is required, or an aging process of electron beam curing and thermosetting is required, it is difficult to perform simple manufacturing.

As a means for solving such a problem, Patent Document 1 discloses that, as a heat transferable protective layer, a layer containing a lubricant and a layer not containing a lubricant are formed in this order from the base sheet side.
A protective layer transfer sheet having an excellent balance between wear resistance and durability such as plasticizer resistance is disclosed.
Patent Document 2 discloses a protective layer transfer film in which a multilayer laminate in which a transparent resin layer, a plasticizer-resistant resin layer, and a thermal adhesive resin layer are sequentially laminated on a base film is disclosed. ing.
However, in any of the methods, there is a problem that the manufacturing process is complicated because the protective layer has a multilayer structure.
JP 2001-096915 A JP 7-156567 A

In view of the above, an object of the present invention is to provide a protective layer resin composition capable of forming a protective layer having excellent transparency, plasticizer resistance, and abrasion resistance on an image.

The present invention is a resin composition used for a protective layer for protecting an image, containing 0.1 to 100 parts by weight of a layered silicate with respect to 100 parts by weight of a resin, and formed into a film having a thickness of 1 mm. It is the resin composition for protective layers whose total light transmittance measured by the method based on JISK7105 is 65% or more.
The present invention is described in detail below.

As a result of intensive studies, the present inventors have used a resin composition in which a layered silicate is highly dispersed, and have high transparency and excellent plasticizer resistance. The inventors have found that a protective layer capable of satisfactorily protecting the formed image is obtained, and have completed the present invention.

The resin composition for protective layers of the present invention contains a resin.
The resin is not particularly limited as long as it is excellent in transparency. For example, (meth) acrylic ester resin, polyimide resin, epoxy resin, silicone resin, benzocyclobutene resin, fluorine resin , Polyurethane resins, polycarbonate resins, norbornene resins, polyolefin resins, polystyrene resins and the like. These resins have high transparency, and are suitable as a resin composition for a protective layer. Above all,
A (meth) acrylic acid ester-based resin is more preferable because it exhibits excellent transparency, heat resistance, wear resistance, and the like when used in combination with a layered silicate. These resins may be used alone or in combination of two or more.
The (meth) acrylic ester resin is a homopolymer or copolymer of (meth) acrylic ester.

Examples of the (meth) acrylic acid ester-based resin include a general formula CH ₂ ═C (R ¹ ) C.
OO-R ² (wherein, R ¹ represents a hydrogen atom or a methyl group (in the case of an acrylate ester, represents a hydrogen atom, and in the case of a methacrylic acid ester, represents a methyl group), and R ² represents an aliphatic carbonization. A hydrogen group, an aromatic hydrocarbon group, and a monovalent group selected from hydrocarbon groups containing a functional group such as halogen, amine, ether, etc. are preferred.

The (meth) acrylic ester resin is not particularly limited, and examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, (meth)
Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl methacrylate, (
Sec-butyl (meth) acrylate, t-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (
2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, n-tridecyl (meth) acrylate, myristyl (meth) acrylate,
Cetyl (meth) acrylate, stearyl (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, 2-naphthyl (meth) acrylate , 2,4,6-trichlorophenyl (meth) acrylate, 2,4,6-tribromophenyl (meth) acrylate, isobornyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, (meth) 2-ethoxyethyl acrylate, (meth) acrylic acid diethylene glycol monomethyl ether, (meth) acrylic acid polyethylene glycol monomethyl ether, (meth) acrylic acid polypropylene glycol monomethyl ether, (meth) acrylic acid tetrahydrofluoryl, (meth) acrylic acid 2,3-dibromopropi , 2-chloroethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, hexafluoroisopropyl (meth) acrylate, glycidyl (meth) acrylate, 3-trimethoxy (meth) acrylate Examples include silylpropyl, 2-diethylaminoethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, and the like. These (meth) acrylic acid ester resins may be used alone or in combination of two or more.

The (meth) acrylic acid ester-based resin can be improved in wear resistance and heat resistance by being crosslinked and modified by various methods. The method for crosslinking is not particularly limited, and examples thereof include a method in which a crosslinking assistant is added to a predetermined amount of (meth) acrylic acid ester monomer and polymerized.

The crosslinking aid is not particularly limited, and examples thereof include radical generators such as benzoyl peroxide, divinylbenzene, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9 -Polyfunctional monomers such as nonanediol di (meth) acrylate and 1,2,4-benzenetricarboxylic acid triallyl ester. These crosslinking aids may be used alone or in combination of two or more.

The resin composition for protective layers of the present invention contains a layered silicate.
The layered silicate is not particularly limited, and examples thereof include smectite clay minerals such as montmorillonite, hectorite, saponite, beidellite, stevensite, and nontronite, swelling mica, vermiculite, and halloysite. Among these, at least one selected from the group consisting of montmorillonite, hectorite, swellable mica and vermiculite is preferably used. In order to achieve both high transparency and low linear expansion coefficient, it is preferable to use hectorite, particularly synthetic hectorite. These layered silicates may be used alone or in combination of two or more.
In the present specification, the layered silicate means a layered silicate compound having a structure having a plurality of layers composed of a plurality of flaky crystals and having an exchangeable metal cation between the layers.
The layered silicate may be a natural product or a synthetic product.

Although it does not specifically limit as a crystal shape of the said layered silicate, The upper limit with the preferable average length of the layered crystal single layer of the said layered silicate is 0.5 micrometer. When it exceeds 0.5 μm, transparency is lowered when a protective layer is formed. A more preferable upper limit is 0.3 μm.

The preferred lower limit of the thickness of the layered silicate is 0.001 μm, the upper limit is 1 μm, the preferred lower limit of the aspect ratio is 20, the upper limit is 500, and the more preferred lower limit of the thickness is 0.001.
A more preferable upper limit of μm and thickness is 0.5 μm.

The layered silicate preferably has a large shape anisotropy effect defined by the following formula (1).
By using a layered silicate having a large shape anisotropy effect, it is possible to express the superior mechanical properties of the present invention.

The exchangeable metal cation existing between the layers of the layered silicate means a metal ion such as sodium or calcium existing on the surface of the lamellar crystal of the layered silicate, and these metal ions are cations with the cationic substance. Since it has exchangeability, various substances having cationic properties can be inserted (intercalated) between the crystal layers of the layered silicate.

Although it does not specifically limit as a cation exchange capacity | capacitance of the said layered silicate, A preferable minimum is 50 milliequivalent / 100g, and an upper limit is 200 milliequivalent / 100g. When the amount is less than 50 milliequivalents / 100 g, the amount of the cationic substance intercalated between the crystal layers of the layered silicate is reduced by cation exchange, so that the crystal layers are not sufficiently depolarized (hydrophobized). Sometimes. If it exceeds 200 milliequivalents / 100 g, the bonding strength between the crystal layers of the layered silicate becomes too strong, and the crystal flakes may be difficult to peel.

As the layered silicate, those having improved dispersibility in the resin by chemical treatment are preferable. Hereinafter, such a layered silicate is also referred to as an organic layered silicate.

As said chemical treatment, it can implement by the chemical modification (1) method-chemical modification (6) method shown below, for example. These chemical modification methods may be used alone or in combination of two or more.

The chemical modification (1) method is also referred to as a cation exchange method using a cationic surfactant. Specifically, when the protective layer resin composition of the present invention is obtained using a low-polarity resin, the layered silicate is previously prepared. In this method, the interlayer is subjected to cation exchange with a cationic surfactant to make it hydrophobic. By hydrophobing the layered silicate layer in advance, the affinity between the layered silicate and the low-polarity resin such as polyolefin resin is increased, and the layered silicate can be finely dispersed more uniformly in the low-polarity resin. .

The cationic surfactant is not particularly limited, and examples thereof include quaternary ammonium salts and quaternary phosphonium salts. Especially, since the crystal | crystallization layer of layered silicate can fully be hydrophobized, a C6 or more alkyl ammonium ion salt, aromatic quaternary ammonium ion salt, or heterocyclic quaternary ammonium ion salt is used suitably.

The quaternary ammonium salt is not particularly limited, and examples thereof include trimethyl alkyl ammonium salt, triethyl alkyl ammonium salt, tributyl alkyl ammonium salt, dimethyl dialkyl ammonium salt, dibutyl dialkyl ammonium salt, methyl benzyl dialkyl ammonium salt, and dibenzyl dialkyl ammonium salt. , Trialkylmethylammonium salt, trialkylethylammonium salt, trialkylbutylammonium salt; benzylmethyl {2- [2- (p-1,1,3,3-tetramethylbutylphenoxy) ethoxy] ethyl} ammonium chloride A quaternary ammonium salt having an aromatic ring such as
Quaternary ammonium salts derived from aromatic amines such as trimethylphenylammonium; quaternary ammonium salts having heterocycles such as alkylpyridinium salts and imidazolium salts; dialkyl quaternary ammonium salts having two pore ethylene glycol chains, polypropylene glycol chains A dialkyl quaternary ammonium salt having two polyethylene glycol chains, a trialkyl quaternary ammonium salt having one polyethylene glycol chain, a trialkyl quaternary ammonium salt having one polypropylene glycol chain, and the like. Among them, lauryltrimethylammonium salt,
Stearyl trimethyl ammonium salt, trioctyl methyl ammonium salt, distearyl dimethyl ammonium salt, di-cured tallow dimethyl ammonium salt, distearyl dibenzyl ammonium salt, N-polyoxyethylene-N-lauryl-N, N-dimethyl ammonium salt, etc. Is preferred. These quaternary ammonium salts may be used alone or in combination of two or more.

The quaternary phosphonium salt is not particularly limited. For example, dodecyltriphenylphosphonium salt, methyltriphenylphosphonium salt, lauryltrimethylphosphonium salt, stearyltrimethylphosphonium salt, trioctylmethylphosphonium salt, distearyldimethylphosphonium salt, distearyl And dibenzylphosphonium salts. These quaternary phosphonium salts may be used alone or in combination of two or more.

In the chemical modification (2) method, a hydroxyl group present on the crystal surface of the organically modified layered silicate chemically treated by the chemical modification (1) method has a chemical affinity with a functional group or a hydroxyl group capable of chemically bonding to the hydroxyl group. This is a method of chemical treatment with a compound having one or more large functional groups at the molecular end.

The functional group capable of chemically bonding to the hydroxyl group or the functional group having a large chemical affinity with the hydroxyl group is not particularly limited, and examples thereof include an alkoxy group, a glycidyl group, a carboxyl group (including dibasic acid anhydrides), A hydroxyl group, an isocyanate group, an aldehyde group, etc. are mentioned.

The compound having a functional group capable of chemically bonding to the hydroxyl group or the compound having a functional group having a large chemical affinity with the hydroxyl group is not particularly limited. For example, a silane compound, titanate compound, or glycidyl compound having the functional group. , Carboxylic acids, alcohols and the like. These compounds may be used independently and 2 or more types may be used together.

The silane compound is not particularly limited, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-amino. Propyldimethylmethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethylethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, hexyltrimethoxysilane, hexyltri Ethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltriethoxysilane, N-β- (aminoethyl) γ-a Nopropylmethyldimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltri An ethoxysilane etc. are mentioned. These silane compounds may be used independently and 2 or more types may be used together.

In the chemical modification (3) method, the hydroxyl group present on the crystal surface of the organically modified layered silicate chemically treated by the chemical modification (1) method has a functional group capable of chemically bonding to the hydroxyl group or a chemical affinity with the hydroxyl group. This is a method of chemically treating a compound having at least one large functional group and one reactive functional group at the molecular end.

The chemical modification (4) method is a method in which the crystal surface of the organically modified layered silicate chemically treated by the chemical modification (1) method is chemically treated with a compound having an anionic surface activity.

The compound having an anionic surface activity is not particularly limited as long as the layered silicate can be chemically treated by ionic interaction. For example, sodium laurate, sodium stearate, sodium oleate, higher alcohol sulfate ester salt , Secondary higher alcohol sulfates, unsaturated alcohol sulfates and the like. These compounds may be used independently and 2 or more types may be used together.

The chemical modification (5) method is a method of chemically treating a compound having one or more reactive functional groups in addition to the anion site in the molecular chain among the compounds having anionic surface activity.

In the chemical modification (6) method, the organically modified layered silicate chemically treated by any one of the chemical modification (1) method to the chemical modification (5) method is further used, for example, maleic anhydride-modified polyethylene or anhydrous This is a method using a resin having a functional group capable of reacting with a layered silicate such as a maleic acid-modified polypropylene resin.

In the resin composition for protective layer of the present invention, the layered silicate has an average interlayer distance of (001) plane measured by a wide angle X-ray diffraction measurement method of 3 nm or more, and a part or all of the laminate. Is preferably dispersed in 5 layers or less. When the average interlayer distance of the layered silicate is 3 nm or more and part or all of the laminate is dispersed in 5 layers or less, the interface area between the resin and the layered silicate is sufficiently large, and Since the distance between the lamellar crystals of the layered silicate becomes appropriate, the improvement effect by dispersion can be sufficiently obtained in the plasticizer resistance, and excellent transparency can be realized.
Moreover, also in the protective layer formed using the resin composition for protective layers of this invention, the said layered silicate has an average interlayer distance of (001) plane measured by wide-angle X-ray-diffraction measuring method at 3 nm or more. It is preferable that some or all of the laminates are dispersed in 5 layers or less.

In the present specification, the average interlayer distance of the layered silicate means the average distance between layers when the flaky crystal of the layered silicate is regarded as a layer, and X-ray diffraction peak and transmission electron microscope photography That is, it can be calculated by a wide-angle X-ray diffraction measurement method.

Specifically, when a part or all of the layered silicate is dispersed as a laminate of 5 layers or less, specifically, the interaction between the layered silicate flaky crystals is weakened and a part of the flaky crystal laminated body Or it means that everything is dispersed. Preferably, 10% or more of the layered silicate laminate is dispersed as 5 or less layers, and 20% or more of the layered silicate laminate is dispersed as 5 or less layers. More preferred.

In addition, the ratio of the layered silicate dispersed as a laminate of 5 layers or less is a layered state that can be observed in a fixed area by observing the resin composition by 50,000 to 100,000 times with a transmission electron microscope. It can be calculated from the following formula (2) by measuring the total number of layers X of the silicate laminate and the number of layers Y of the laminate dispersed as a laminate of 5 layers or less.

The number of layers in the layered silicate laminate is preferably 5 layers or less, more preferably 3 layers or less, and even more preferably 1 layer in order to obtain the effect of dispersion of the layered silicate. is there.

When a protective layer is formed using the protective layer resin composition of the present invention, the dispersed layered silicate is arranged in parallel with the protective layer formed, so that an external chemical (plasticizer) permeates. Since the path | route at the time of doing becomes long, the outstanding chemical resistance and plasticizer resistance are realizable.
The mobility of the plasticizer or the like when the protective layer is formed using the protective layer resin composition of the present invention can be determined by the following formula (3).
Pn = Pp × φp / (1+ (L / 2t) × φc) (3)
In the formula, Pn represents the mobility (g / m ² / day) of a chemical (plasticizer) in a protective layer formed using the resin composition for a protective layer of the present invention, and Pp represents the protection of the present invention. Represents the mobility (g / m ² / day) of chemicals (plasticizer) in the resin of the protective layer formed using the resin composition for layers, φp
Represents the volume fraction (%) of the resin, φc represents the volume fraction (%) of the layered silicate, L represents the average length (m) of the layered crystal monolayer of the layered silicate, and t represents the layered It represents the average thickness (m) of the layered crystal monolayer of silicate.
From the above formula (3), it can be seen that the mobility of the chemical (plasticizer) in the protective layer is small when the volume fraction of the layered silicate is high and the layered silicate is in a highly dispersed state. Therefore, when the layered silicate is highly dispersed in the protective layer, the mobility of the chemical (plasticizer) is hindered, and excellent plasticizer resistance can be realized.

In the protective layer resin composition of the present invention, the lower limit of the content of the layered silicate with respect to 100 parts by weight of the resin is 0.1 part by weight, and the upper limit is 100 parts by weight. When the amount is less than 0.1 part by weight, the effect of improving the plasticizer resistance is reduced, and when the amount exceeds 100 parts by weight, the density of the resin composition for the protective layer becomes too high and becomes brittle. Becomes scarce. A preferred lower limit is 1 part by weight and a preferred upper limit is 75 parts by weight. A more preferred lower limit is 5, and a more preferred upper limit is 65 parts by weight.

The protective layer resin composition of the present invention includes a modification thermoplastic resin, rubber component, oligomers, nucleation, and the like, in order to modify the properties as necessary within a range that does not hinder the achievement of the present invention. Agent, antioxidant (anti-aging agent), heat stabilizer, light stabilizer, lubricant, flame retardant, anti-fogging agent, fiber, inorganic filler,
Additives such as flame retardants, ultraviolet absorbers, antistatic agents, higher fatty acid salts, and inorganic substances may be blended. These may be used independently and 2 or more types may be used together.

The thermoplastic resin for modification is not particularly limited, and examples thereof include polyolefin resins, modified polyolefin resins, polystyrene resins, polyvinyl chloride resins, polyamide resins, polycarbonate resins, polysulfone resins, and polyester resins.

The rubber component is not particularly limited. For example, natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), polychloroprene, Examples include butyl rubber, acrylic rubber, silicon rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, ester-based thermoplastic elastomer, and amide-based thermoplastic elastomer.

The antioxidant is not particularly limited. For example, 1,3,5-trimethyl-2,4,6
-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propioni Loxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5]
Examples include hindered phenolic antioxidants such as undecane.

The heat stabilizer is not particularly limited, and examples thereof include tris (2,4-di-t-butylphenyl) phosphite, trilauryl phosphite, 2-t-butyl-α- (3-t-butyl-4 -Hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite,
Dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, pentaerythryltetrakis (3-laurylthiopropionate), ditridecyl 3,3′-thiodipropionate, etc. It is done.

The fibers are not particularly limited, and examples thereof include glass fibers, carbon fibers, boron fibers, silicon carbide fibers, alumina fibers, amorphous fibers, inorganic fibers such as silicon / titanium / carbon fibers, and organic fibers such as aramid fibers. Can be mentioned.
The inorganic filler is not particularly limited, and examples thereof include layered double hydrates such as calcium carbonate, titanium oxide, mica, talc, barium sulfate, alumina, silicon oxide, and hydrotalcite.

The flame retardant is not particularly limited. For example, hexabromocyclododecane, tris- (
2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether and the like.
The ultraviolet absorber is not particularly limited, and examples thereof include pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2.
'-Carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, etc. are mentioned.

The antistatic agent is not particularly limited, and examples thereof include N, N-bis (hydroxyethyl) alkylamine, alkylallyl sulfonate, and alkyl sulfonate.
The higher fatty acid salt is not particularly limited, and examples thereof include sodium stearate, barium stearate, and sodium palmitate.
Examples of the inorganic material include barium sulfate, alumina, and silicon oxide.

In the protective layer resin composition, the area of the interface between the resin and the layered silicate is sufficiently large because the layered silicate is dispersed. Thereby, since the interaction between the resin and the surface of the layered silicate is increased, excellent plasticizer resistance can be realized.
The protective layer resin composition of the present invention is excellent in transparency because the flaky crystals of the layered silicate are separated in nano order and the layered silicate is finely dispersed.

The resin composition for a protective layer of the present invention is JIS K when formed into a film having a thickness of 1 mm.
The total light transmittance measured by a method based on 7105 is 65% or more. If it is less than 65%, the transparency is lowered, and the use as a protective layer for protecting an image may be restricted. More preferably, it is 75% or more, More preferably, it is 85% or more.
In addition, it does not specifically limit as a method of shape | molding the said resin composition for protective layers in a film form, For example, shaping | molding means, such as extrusion molding, injection molding, and compression molding, can be used.

The method for producing the resin composition for a protective layer of the present invention by dispersing a layered silicate (including an organically modified layered silicate) in the resin is not particularly limited. For example, a resin and a layered silicate are conventionally used. The method of foaming the resin with a foaming agent after mixing by the method, the method of using a dispersant, the method of polymerizing after dispersing the layered silicate in the resin forming monomer, the layered silicate or swelling in the solution in which the resin is dissolved And a method of mixing a solution containing the layered silicate. By using these production methods, the layered silicate can be uniformly and finely dispersed in the resin.

In the method in which the resin and the layered silicate are mixed by a conventional method and the resin is foamed with a foaming agent, the energy of foaming is used for the dispersion of the layered silicate. As the foaming agent,
Although it does not specifically limit, For example, a gaseous foaming agent, an easily volatile liquid foaming agent, a heat decomposable solid foaming agent etc. are mentioned. These foaming agents may be used independently and 2 or more types may be used together.

The method of foaming the resin with a foaming agent after mixing the resin and the layered silicate by a conventional method is not particularly limited. For example, a gaseous foaming agent is added to a resin composition comprising the resin and the layered silicate under high pressure. After the impregnation, the gaseous foaming agent is vaporized in the resin composition to form a foam, and a thermally decomposable foaming agent is previously contained between the layers of the layered silicate, and the thermally decomposable foaming agent. And a method of decomposing the foam by heating to form a foam.

As a dispersion method by the above polymerization, in addition to the method of polymerizing after dispersing the layered silicate in the resin-generating monomer, the layered silicate is dispersed in water and the resin-producing monomer is suspended therein. Examples of the method include polymerization and emulsion polymerization. In this case, the layered silicate has a good dispersion state when the metal ions contained as exchangeable cations in the crystal structure are sodium ions.

The dispersion method by polymerization will be described in detail. For example, a layered silicate is first added to water and stirred to be in a swollen or suspended state, and then a radical polymerizable monomer, a polymerization initiator and a dispersant for resin formation are used. By adding (including protective colloid) and radical polymerization of the monomer, a resin in which the layered silicate is dispersed can be obtained. At this time, when the layered silicate is dispersed in water in advance, the frequency of approach between the resin particles produced by suspension polymerization or emulsion polymerization and the layered silicate increases. As a result, the resin easily adheres to the periphery of the layered silicate, and the resin in which the layered silicate is dispersed in a simple polymerization form such as suspension polymerization or emulsion polymerization in an aqueous medium is efficient. Can be produced.

The polymerization initiator is not particularly limited as long as it is a compound that generates water-soluble free radicals, and examples thereof include inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. Examples thereof include oxide initiators, azo initiators such as 4,4′-azobis-4-cyanovaleric acid, and redox initiators. These polymerization initiators may be used alone or in combination of two or more.

The dispersant is added for the purpose of improving the dispersion stability of a resin obtained by polymerizing the radical polymerizable monomer and efficiently obtaining a resin in which the layered silicate is uniformly dispersed. The dispersant is not particularly limited, and examples thereof include anionic surfactants, nonionic surfactants, partially saponified polyvinyl acetate (polyvinyl alcohol), cellulose dispersants, and gelatin. Among these, anionic surfactants are preferably used, and sodium alkylbenzene sulfonate and the like are particularly preferably used. These dispersants may be used alone or in combination of two or more.
In the polymerization in the aqueous medium, one type of various additives such as a pH adjuster, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, and an antifoaming agent is used as necessary. Or you may add 2 or more types.

The emulsion polymerization method is roughly divided into a monomer addition method and an emulsion addition method depending on the difference in the monomer addition method, but is not particularly limited.
In the monomer addition method, for example, first, a layered silicate is added to a jacketed polymerization reaction tank together with ion-exchanged water, and the layered silicate is brought into a swollen state or a suspended state by a stirring blade. Next, after reducing the pressure inside the polymerization reaction tank to remove oxygen, the pressure was returned to atmospheric pressure with nitrogen,
Under a nitrogen atmosphere, a polymerization initiator and a dispersant are added to the polymerization reaction tank, and the temperature inside the tank is increased to a predetermined temperature by a jacket, and radically polymerizable monomers are added all at once into the polymerization reaction tank, or In this method, polymerization is carried out by dropping (a divided addition) by a certain amount.

In the emulsion addition method, for example, first, the temperature in the polymerization reaction tank is raised to a predetermined temperature by the same operation as in the monomer addition method. Next, the radical polymerizable monomer mixed and emulsified (emulsified) in advance with a part of the dispersing agent and the charged water is added all at once into the polymerization reaction tank, or by dropping a predetermined amount (split addition). This is a polymerization method.

The solid content of the dispersion (slurry) composed of the resin and layered silicate obtained by the polymerization is not particularly limited, but 1 to 50% by weight in consideration of productivity and stability of the polymerization reaction.
It is preferable that

The average particle diameter of the composite of the resin and the layered silicate in the slurry varies depending on the application and usage method and is not particularly limited. For example, when used as a slurry, a preferable lower limit is 0.01 μm. The preferable upper limit is 30 μm. When the average particle diameter exceeds 30 μm, the composite and the aqueous medium may be easily separated.
When the composite is dried and used as a powder, the more preferable lower limit is 10 μm and the more preferable upper limit is 3000 μm in consideration of the operability of the drying process.

The resin composition for a protective layer of the present invention can be formed into a protective layer for protecting an image by forming it into a film. Such a protective layer is also one aspect of the present invention.
The method for forming the film is not particularly limited. For example, extrusion molding, injection molding,
Molding means such as compression molding can be used.

Moreover, it can be set as a protective layer formation image by laminating | stacking the protective layer formed using the resin composition for protective layers of this invention on an image. Such a protective layer-formed image is also one aspect of the present invention.
The image is not particularly limited. For example, the dye is formed by heat-sensitive sublimation transfer in which the dye in the color material layer is sublimed and diffused by heat and the dye moves to the image receiving sheet, and the color material layer is melted and softened by heating. Examples thereof include those formed by heat-sensitive melt transfer in which the color material layer itself is transferred to the image receiving sheet, ink jet, and electrophotography.
The method for laminating the protective layer on the image is not particularly limited. For example, a method for laminating and pouching a film formed using the resin composition for a protective layer of the present invention, for the protective layer of the present invention. There is a method in which the resin composition is thermally transferred by the same thermal head as that for image formation.
A method for protecting an image using a protective layer comprising the resin composition for a protective layer of the present invention is also one aspect of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the resin composition for protective layers which can form the protective layer which has the chemical-resistance, plasticizer resistance, and durability which were excellent on the image can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited only to these examples.

(Example 1)
A synthetic hectorite (trade name “Lucentite ST”) in which a separable flask was subjected to an organic treatment with 200 parts by weight of toluene and trioctylmethylammonium salt as a layered silicate.
N ”(manufactured by Coop Chemical Co., Ltd.) was added, and the gas phase in the separable flask was replaced with nitrogen gas, heated to the boiling point of toluene, and stirred while refluxing of toluene occurred ( Solution polymerization was performed while dropwise adding a mixed solution in which 95 parts by weight of methyl acrylate, 5 parts by weight of (meth) acrylic acid and 3 parts by weight of benzoyl peroxide (polymerization initiator) were dropped over 3 hours.
After completion of the dropwise addition of the mixed solution, the mixture was further aged for 2 hours with stirring under reflux of toluene. Then, toluene was removed under reduced pressure while gradually raising the temperature to 180 ° C. to obtain a protective layer resin composition.
About this protective layer resin composition, when the molecular weight distribution by gel permeation chromatography (GPC) was measured using a GPC measuring apparatus, it had a maximum peak in the region of molecular weight 40,000. In addition, as a GPC measuring apparatus, HTR-C made by Nihon Millipore Limited is used, and KF-800P (one) made by Showa Denko KK is used for the column.
What connected KF-806M (2 pieces) and KF-802.5 (1 piece) in series was used.
The measurement temperature was 40 ° C., the sample was a 0.2 wt% THF solution (passed through a 0.45 μm filter), the injection volume was 100 μl, and standard polystyrene was used as a calibration sample.
Subsequently, the obtained resin composition for protective layers was shape | molded by 160 degreeC hot press, and the plate-shaped molded object of thickness 1mm was produced.

(Comparative Example 1)
A protective layer resin composition and a plate-like molded body were produced in the same manner as in Example 1 except that the layered silicate was not used.

(Evaluation)
About the resin composition for protective layers and the plate-like molded product produced in Example 1 and Comparative Example 1, the total light transmittance, the average interlayer distance, the dispersion state of the layered silicate, the plasticizer resistance test, the dye by the following methods Migration was evaluated.
These results are shown in Table 1.

(1) Total light transmittance Ultraviolet spectrophotometer (manufactured by Hitachi, Ltd., Spect) using a plate-like molded product having a thickness of 1 mm.
rophotometer U-4000), measuring wavelength 850 nm, measuring thickness 1 mm
The total light transmittance of the measuring light was measured.

(2) Thickness of 100 μm using a layered silicate average interlayer distance X-ray diffractometer (trade name “RINT1100”, manufactured by Rigaku Corporation)
Measure the 2θ of the diffraction peak obtained from the diffraction of the layered surface of the layered silicate in the plate-shaped molded product of m,
The (001) plane spacing of the layered silicate was calculated using the Bragg diffraction formula below.
λ = 2 dsin θ
Here, λ = 0.154 nm, d: interplanar spacing of the layered silicate, θ: diffraction angle, and d obtained by this formula was defined as an average interlayer distance (nm).

(3) Dispersion state of layered silicate According to a transmission electron microscope (TEM, trade name “JEM-1200EX II”, manufactured by JEOL Ltd.) photograph, the dispersion state of layered silicate in a plate-shaped molded product having a thickness of 100 μm ( Observe the peeled state)
The dispersion state was evaluated according to the following criteria.
[Criteria]
○ ... At least a portion was dispersed in 5 layers or less.
X ... All were over 5 layers.

(4) Plasticizer resistance test After the obtained protective resin composition was dissolved in a toluene solvent and coated on a PET film, 1
It dried in 00 degreeC oven. The obtained sheet was put on a drop of plasticizer (DOP), bonded to a sheet made of soft vinyl chloride, sandwiched between press plates, subjected to a load of 40 g / cm ² , kept at 82 ° C. for 24 hours, and cracked on the surface. Was visually evaluated.
[Criteria]
○: No cracks are observed.
Δ: Some cracks are observed.
X: A crack is recognized.

(5) After printing with a full-color test pattern with a dye transfer sublimation transfer printer (Olympus printer P-330), the protective layer resin composition is transferred to the surface of the obtained image. A protective layer was formed. After that, the soft vinyl chloride sheet and the image surface of the image on which the protective layer is formed are superposed, a load of 40 g / cm ² is applied, and the temperature is kept at 82 ° C. for 24 hours. It was visually examined whether it migrated.
[Criteria]
○: Dye transfer is not recognized.
Δ: Dye transfer is slightly observed.
X: Dye transfer is recognized

ADVANTAGE OF THE INVENTION According to this invention, the resin composition for protective layers which can form the protective layer which has the outstanding chemical resistance, plasticizer resistance, and durability on an image can be provided.

Claims (7)

A resin composition used for a protective layer for protecting an image, comprising 0.1 to 100 parts by weight of a layered silicate with respect to 100 parts by weight of a resin, and formed into a film having a thickness of 1 mm.
A resin composition for a protective layer, wherein the total light transmittance measured by a method according to S K 7105 is 65% or more. The resin composition for a protective layer according to claim 1, wherein the resin is a (meth) acrylic ester resin. The resin composition for a protective layer according to claim 1 or 2, wherein the resin is a copolymer of (meth) acrylic acid ester and (meth) acrylic acid. 4. The protective layer resin composition according to claim 1, wherein the layered silicate has an average length of a layered crystal single layer of 0.5 μm or less. The layered silicate is at least one selected from the group consisting of montmorillonite, hectorite, swellable mica, and vermiculite.
The resin composition for protective layers as described. 6. The protective layer resin composition according to claim 1, 2, 3, 4, or 5, wherein the layered silicate contains an alkyl ammonium ion having 6 or more carbon atoms. The layered silicate has an average interlayer distance of 3n on the (001) plane measured by wide-angle X-ray diffractometry.
The protective layer resin composition according to claim 1, 2, 3, 4, 5 or 6, wherein m or more and a part or all of them are dispersed as a laminate of 5 layers or less.