JP2017187675A - Transparent magnetic sheet and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sheet capable of reducing an effect of a member for imparting a magnetic attraction force, to a display.SOLUTION: A transparent magnetic sheet 10 includes a transparent magnetic layer 2 containing a transparent resin 2R and magnetic substance particles 2M dispersed in the transparent resin 2R. An average particle diameter of the magnetic substance particles 2M is 1 μm or less. The transparent magnetic layer 2 contains the magnetic substance particle 2M at a ratio of 0.1-5 mass%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transparent magnetic sheet and printed matter.

  As recording sheets used for printing applications, recording sheets based on transparent sheets have been proposed so far. In these recording sheets, a layer that facilitates recording of information by printing, for example, an ink-jet ink receiving layer, a thermal transfer image receiving layer, and a toner receiving layer is provided on the transparent sheet.

  The printed matter obtained by printing information on such a recording sheet, when posting information, is stuck on a bulletin board using an adhesive tape, fastened to a bulletin board with a thumbtack or the like, or a bulletin board with a magnet piece or rubber magnet tape It was necessary to keep it on. Therefore, when posting information using the above recording sheet, it takes time to install the printed matter on the bulletin board, which causes stabs on the printed matter and the bulletin board, and the adhesive is removed when the installation and removal are repeated. In many cases, inconvenience such as remaining on the bulletin board occurred.

  Also, since it is cumbersome to prepare and use a sticking tool for posting, it is possible to use a magnetic sheet in which a rubber magnetic tape is attached to a transparent recording sheet as a device for improving its convenience. it was thought. This makes it easy to post information by using a bulletin board with a magnet attached thereto. However, since the rubber magnetic tape has a thickness of 300 μm or more, such a magnetic sheet has a disadvantage that it is very thick compared to a normal recording paper and cannot be used in a printer or the like.

  In Patent Document 1, for this problem, a belt-like magnet layer is formed on a part of a transparent substrate sheet, and the difference between the thickness of the part corresponding to the magnet layer and the thickness of the other part is disclosed. The use of a magnetic sheet having a thickness of 100 μm or less is described. This magnetic sheet can also be used in a printer or the like.

JP 2002-137320 A

In the magnetic sheet described in the above patent document, the transmittance of the portion corresponding to the magnet layer is significantly lower than the transmittance of other portions. For this reason, there is a problem that the printed matter obtained by printing information on the recording sheet shows the magnet layer through.
In view of the above, an object of the present invention is to provide a magnetic sheet having a small influence on a display by a member for applying a magnetic attraction force.

  According to a first aspect of the present invention, there is provided a transparent magnetic layer comprising a transparent resin and magnetic particles dispersed in the transparent resin, the average particle size of the magnetic particles being 1 μm or less, and the transparent magnetic A transparent magnetic sheet in which the ratio of the magnetic particles in the layer is in the range of 0.1 to 5% by mass is provided.

  According to the 2nd side surface of this invention, the printed matter provided with the transparent magnetic sheet which concerns on a 1st side surface, and the printing layer supported by the said transparent magnetic sheet is provided.

  According to the present invention, a magnetic sheet having a small influence on a display by a member for applying a magnetic attraction force is provided.

1 is a cross-sectional view schematically showing a transparent magnetic sheet according to an embodiment of the present invention. Sectional drawing which shows roughly an example of the printed matter obtained using the transparent magnetic sheet shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The terms “sheet” and “film” used here mean an article having a thin layer shape and flexibility, and does not include the concept of thickness.

<Configuration of transparent magnetic sheet>
FIG. 1 is a cross-sectional view schematically showing a transparent magnetic sheet according to an embodiment of the present invention.
The transparent magnetic sheet 10 shown in FIG. 1 is transparent and adheres to an article made of a soft magnetic material such as an iron plate by magnetic force (that is, magnetically adsorbs). According to an example, the transparent magnetic sheet 10 has flexibility.

  The transparent magnetic sheet 10 is excellent in transparency and has a high transmittance. The total light transmittance of the transparent magnetic sheet 10 is preferably 30% or more and less than 85%. The higher the total light transmittance, the higher the visibility of the article behind the transparent magnetic sheet 10. However, in order to increase the total light transmittance, it is necessary to reduce the function as a magnet.

  Here, the “total light transmittance” of the transparent magnetic sheet 10 is a value obtained by performing measurement in accordance with ISO13468-1. For this measurement, for example, a haze meter NDH7000SP manufactured by Nippon Denshoku Industries Co., Ltd. is used.

  The thickness of the transparent magnetic sheet 10 is preferably in the range of 50 to 260 μm, and more preferably in the range of 100 to 260 μm. When the transparent magnetic sheet 10 is too thin, there is a possibility that sufficient strength cannot be achieved or the attractive force of the transparent magnetic sheet may be reduced. When the transparent magnetic sheet 10 is too thick, it may be difficult to form a print layer on the transparent magnetic sheet 10 using an image forming apparatus such as a printer.

  The transparent magnetic sheet 10 includes a transparent substrate 1 and a transparent magnetic layer 2. The transparent magnetic sheet 10 may further include an underlayer as a layer that facilitates recording of information by printing. Examples of the base layer include an ink jet ink receiving layer, a thermal transfer image receiving layer, and a toner receiving layer.

  The transparent substrate 1 is a transparent film. The transparent substrate 1 supports the transparent magnetic layer 2. The transparent substrate 1 can be omitted.

  The thickness of the transparent substrate 1 is preferably in the range of 10 to 250 μm, and more preferably in the range of 38 to 75 μm. If the transparent base material 1 is thinned, the strength of the transparent magnetic sheet 10 may be reduced, or the transparent base material 1 may be easily broken during the manufacturing process of the transparent magnetic sheet 10. If the transparent substrate 1 is thickened, the transmittance and flexibility of the transparent magnetic sheet 10 may be reduced.

  Examples of the transparent substrate 1 include polyolefin films such as polyethylene film and polypropylene film; polyester films such as polyethylene terephthalate film and polyethylene naphthalate film; cellulose-based films such as triacetyl cellulose film, diacetyl cellulose film, and cellophane; -Polyamide film such as nylon film and 6,6-nylon film; Acrylic resin film such as polymethylmethacrylate film; Polystyrene film; Polyvinyl chloride film; Polyimide film; Polyvinyl alcohol film; Polycarbonate film; Can be mentioned. In addition, the transparent base material 1 is not necessarily limited to the film illustrated here.

  The transparent magnetic layer 2 is supported on the transparent substrate 1. According to an example, the transparent magnetic layer 2 is formed on the transparent substrate 1.

  The thickness of the transparent magnetic layer 2 is preferably in the range of 50 to 260 μm, and more preferably in the range of 100 to 260 μm. If the transparent magnetic layer 2 is thinned, the magnetic attractive force of the transparent magnetic sheet 10 may be insufficient, or the strength of the transparent magnetic layer 2 may be insufficient. If the transparent magnetic layer 2 is thickened, the transmittance and flexibility of the transparent magnetic sheet 10 may be reduced.

The transparent magnetic layer 2 includes a transparent resin 2R and magnetic particles 2M.
The magnetic particles 2M are dispersed in the transparent resin 2R. The magnetic particles 2M allow the transparent magnetic sheet 10 to be magnetically attracted to a support including a ferromagnetic material such as iron, nickel, and chromium, such as a bulletin board or a whiteboard.

  The magnetic particles 2M are made of, for example, a hard magnetic material such as an alloy magnet such as KS steel, MT steel, MK steel, and alnico alloy, a ferrite magnet, and a rare earth magnet. As a material of the magnetic particles 2M, a ferrite magnet such as a barium ferrite magnet is preferable. Since the ferrite magnet is an oxide, unlike the alloy magnet, the performance does not deteriorate due to oxidation.

  The average particle size of the magnetic particles 2M is 1 μm or less. In order to sufficiently increase the transmittance of the transparent magnetic sheet 10, it is necessary that the average particle diameter of the magnetic particles 2M be 1 μm or less.

Here, the “average particle diameter” means a value obtained by the following method.
That is, a secondary electron image is taken with a scanning electron microscope (SEM) on the front and back surfaces of the transparent magnetic layer 2. As the SEM, for example, S-4800 manufactured by Hitachi, Ltd. is used. This photographing is performed on a region having a measurement magnification of 20,000 times, an acceleration voltage of, for example, 10 kV, and an area of 200 μm ² . Then, among the magnetic particles shown in the electron micrographs on the front and back surfaces of the transparent magnetic layer 2, those that are visible as a whole are selected, and the area of each of them is determined. The diameter of a circle having an area equal to this area is taken as the particle diameter of the magnetic particles. The average particle diameter of the magnetic particles is obtained by arithmetically averaging the particle diameters thus obtained.

  The average particle diameter of the magnetic particles 2M is preferably 100 nm or less. When the average particle diameter of the magnetic particles 2M is 100 nm or less, the particle diameter of the magnetic particles 2M is sufficiently smaller than the wavelength in the visible light region, and light scattering by the magnetic particles 2M is difficult to occur.

  The average particle diameter of the magnetic particles 2M is preferably 10 nm or more, and more preferably 50 nm or more. The small magnetic particles 2M are difficult to uniformly disperse in the transparent resin 2R.

  The ratio of the magnetic particles 2M in the transparent magnetic layer 2 is in the range of 0.1 to 5.0% by mass. When this ratio is less than 0.1% by mass, a sufficient attractive force cannot be imparted to the transparent magnetic sheet 10. Moreover, when this ratio exceeds 5.0 mass%, sufficient transmittance | permeability cannot be provided to the transparent magnetic sheet 10. FIG.

  The proportion of the magnetic particles 2M in the transparent magnetic layer 2 is more preferably in the range of 0.5 to 2.0% by mass. In this case, the attractive force and transmittance of the transparent magnetic sheet 10 can be particularly increased.

  The transparent resin 2R plays a role as a dispersion medium for dispersing the magnetic particles 2M. Further, the transparent resin 2R plays a role of maintaining the shape of the transparent magnetic layer 2.

  Examples of the transparent resin 2R include (meth) acrylic resins, polyester resins, polyolefin resins, polycarbonate resins, polyamide resins, polyether resins, epoxy resins, oxetane resins, urethane resins, alkyd resins, spearcetal resins, polybutadiene resins, And polythiol polyether resins. The transparent resin 2R is preferably a cured product of a resin composition described below.

<Resin composition>
The resin composition contains an alicyclic epoxy compound (A) and a polyol compound (B). This resin composition can further contain an acid generator (C). Below, each component is demonstrated.

[Alicyclic epoxy compound (A)]
The alicyclic epoxy compound (A) is a compound containing an alicyclic (aliphatic ring) structure and an epoxy group in one molecule. The epoxy group may be composed of two carbon atoms and oxygen atoms adjacent to each other in the alicyclic ring (hereinafter, such an epoxy group is referred to as “alicyclic epoxy group”), and a single bond to the alicyclic ring. May be directly bonded.

  The number of alicyclic structures contained in one molecule of the alicyclic epoxy compound (A) may be 1 or 2 or more. Further, the number of epoxy groups contained in one molecule of the alicyclic epoxy compound (A) may be 1 or 2 or more. According to one example, the alicyclic epoxy compound (A) includes two alicyclic structures and two epoxy groups in one molecule, and the epoxy groups include carbon atoms of different alicyclic structures. It is an alicyclic epoxy group.

  The compound having an alicyclic epoxy group can be arbitrarily selected from known or commonly used compounds. The compound having an alicyclic epoxy group preferably has an epoxy group composed of two carbon atoms and oxygen atoms adjacent to each other in the cyclohexane ring, that is, a compound having a cyclohexene oxide group.

  As the compound having an alicyclic epoxy group, an alicyclic epoxy compound (alicyclic epoxy resin) represented by the following general formula (I) is particularly preferable in terms of heat resistance, light resistance and transparency. Generally, an epoxy compound is excellent in heat resistance. However, since an epoxy compound having a benzene ring, such as a bisphenol A type epoxy compound, has a conjugated double bond, it is inferior in transparency compared to an epoxy compound having no conjugated double bond. When an alicyclic epoxy compound represented by the following general formula (I) is used, particularly high transparency can be achieved.

In the general formula (I), R _{1 to} R ₁₈ are each independently a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group.

  Examples of the organic group include a hydrocarbon group, a group composed of a carbon atom and a halogen atom, a halogen atom, an oxygen atom, a sulfur atom, a nitrogen atom, and silicon, together with a carbon atom and a hydrogen atom. It may be a group containing a hetero atom such as an atom. Examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom.

  The organic group includes a hydrocarbon group, a group consisting of a carbon atom, a hydrogen atom and an oxygen atom, a halogenated hydrocarbon group, a group consisting of a carbon atom, an oxygen atom and a halogen atom, a carbon atom and a hydrogen atom. And a group consisting of an oxygen atom and a halogen atom. When the organic group is a hydrocarbon group, the hydrocarbon group may be an aromatic hydrocarbon group, an aliphatic hydrocarbon group, or a group including an aromatic skeleton and an aliphatic skeleton.

  Specific examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. N-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group Chain alkyl groups such as n-heptadecyl group, n-octadecyl group, n-nonadecyl group and n-icosyl group; vinyl group, 1-propenyl group, 2-n-propenyl group (allyl group), 1-n Chain alkenyl groups such as -butenyl, 2-n-butenyl, and 3-n-butenyl; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl And a cycloalkyl group such as cycloheptyl group; phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, α-naphthyl group, β-naphthyl group, biphenyl-4-yl group, biphenyl-3-yl And aryl groups such as biphenyl-2-yl, anthryl, and phenanthryl; and benzyl, phenethyl, α-naphthylmethyl, β-naphthylmethyl, α-naphthylethyl, and β-naphthyl Examples include aralkyl groups such as an ethyl group.

  Specific examples of the halogenated hydrocarbon group include chloromethyl group, dichloromethyl group, trichloromethyl group, bromomethyl group, dibromomethyl group, tribromomethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 2, 2,2-trifluoroethyl group, pentafluoroethyl group, heptafluoropropyl group, perfluorobutyl group, and perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group, perfluorooctyl group, perfluorononyl group, And halogenated chain alkyl groups such as perfluorodecyl group; 2-chlorocyclohexyl group, 3-chlorocyclohexyl group, 4-chlorocyclohexyl group, 2,4-dichlorocyclohexyl group, 2-bromocyclohexyl group, 3-bromocyclohexyl Group, and A halogenated cycloalkyl group such as bromocyclohexyl group; 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 2, 6-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 2-bromophenyl group, 3-bromophenyl group, 4-bromophenyl group, 2-fluorophenyl group, 3-fluorophenyl group, and Halogenated aryl groups such as 4-fluorophenyl group; and 2-chlorophenylmethyl group, 3-chlorophenylmethyl group, 4-chlorophenylmethyl group, 2-bromophenylmethyl group, 3-bromophenylmethyl group, 4-bromophenyl Methyl group, 2-fluorophenylmethyl group, 3 Fluorophenyl methyl group, and halogenated aralkyl groups such as 4-fluorophenyl methyl groups.

  Specific examples of the group consisting of a carbon atom, a hydrogen atom, and an oxygen atom include hydroxy chains such as a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxy-n-propyl group, and a 4-hydroxy-n-butyl group. Alkyl groups; halogenated cycloalkyl groups such as 2-hydroxycyclohexyl group, 3-hydroxycyclohexyl group, and 4-hydroxycyclohexyl group; 2-hydroxyphenyl group, 3-hydroxyphenyl group, 4-hydroxyphenyl group, 2, Hydroxyaryl such as 3-dihydroxyphenyl group, 2,4-dihydroxyphenyl group, 2,5-dihydroxyphenyl group, 2,6-dihydroxyphenyl group, 3,4-dihydroxyphenyl group, and 3,5-dihydroxyphenyl group Group: 2-hydroxyphenylmethyl group, 3-hydride Hydroxyaralkyl groups such as xyphenylmethyl group and 4-hydroxyphenylmethyl group; methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, isobutyloxy group, sec-butyloxy group, tert- Butyloxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-tridecyloxy group, n-tetradecyloxy group, n-pentadecyloxy group, n-hexadecyloxy group, n-heptadecyloxy group, n-octadecyloxy group, n-nonadecyloxy group, and n-icosyloxy Chain alkoxy groups such as groups; vinyloxy groups, 1 Chain alkenyloxy groups such as propenyloxy group, 2-n-propenyloxy group (allyloxy group), 1-n-butenyloxy group, 2-n-butenyloxy group, and 3-n-butenyloxy group; phenoxy group, o- Tolyloxy group, m-tolyloxy group, p-tolyloxy group, α-naphthyloxy group, β-naphthyloxy group, biphenyl-4-yloxy group, biphenyl-3-yloxy group, biphenyl-2-yloxy group, anthryloxy group And aryloxy groups such as phenanthryloxy group; benzyloxy group, phenethyloxy group, α-naphthylmethyloxy group, β-naphthylmethyloxy group, α-naphthylethyloxy group, β-naphthylethyloxy group, etc. Aralkyloxy group of methoxymethyl group, ethoxymethyl group, n-pro Pyroxymethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-n-propyloxyethyl group, 3-methoxy-n-propyl group, 3-ethoxy-n-propyl group, 3-n-propyloxy Alkoxyalkyl groups such as -n-propyl group, 4-methoxy-n-butyl group, 4-ethoxy-n-butyl group, and 4-n-propyloxy-n-butyl group; methoxymethoxy group, ethoxymethoxy group, n-propyloxymethoxy group, 2-methoxyethoxy group, 2-ethoxyethoxy group, 2-n-propyloxyethoxy group, 3-methoxy-n-propyloxy group, 3-ethoxy-n-propyloxy group, 3- n-propyloxy-n-propyloxy group, 4-methoxy-n-butyloxy group, 4-ethoxy-n-butyloxy group, and 4-n Alkoxyalkoxy groups such as propyloxy-n-butyloxy group; alkoxyaryl groups such as 2-methoxyphenyl group, 3-methoxyphenyl group, and 4-methoxyphenyl group; 2-methoxyphenoxy group, 3-methoxyphenoxy group, and Alkoxyaryloxy groups such as 4-methoxyphenoxy group; aliphatic acyl groups such as formyl group, acetyl group, propionyl group, butanoyl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, and decanoyl group; benzoyl Group, α-naphthoyl group, β-naphthoyl group and other aromatic acyl groups; methoxycarbonyl group, ethoxycarbonyl group, n-propyloxycarbonyl group, n-butyloxycarbonyl group, n-pentyloxycarbonyl group, n- Hexilka Chain alkyloxycarbonyl groups such as bonyl group, n-heptyloxycarbonyl group, n-octyloxycarbonyl group, n-nonyloxycarbonyl group, and n-decyloxycarbonyl group; phenoxycarbonyl group, α-naphthoxycarbonyl group And aryloxycarbonyl groups such as β-naphthoxycarbonyl group; formyloxy group, acetyloxy group, propionyloxy group, butanoyloxy group, pentanoyloxy group, hexanoyloxy group, heptanoyloxy group, octanoyloxy group And aliphatic acyloxy groups such as a nonanoyloxy group and a decanoyloxy group; and aromatic acyloxy groups such as a benzoyloxy group, an α-naphthoyloxy group, and a β-naphthoyloxy group.

R _{1 to} R ₁₈ are more preferably all hydrogen atoms, particularly from the viewpoint of the hardness of the cured product obtained using the curable composition.

  In the general formula (I), X is a single bond or a linking group (a divalent group having one or more atoms).

  Examples of the linking group include divalent hydrocarbon groups, carbonyl groups, ether groups (ether bonds), thioether groups (thioether bonds), ester groups (ester bonds), carbonate groups (carbonate bonds), amide groups (amides). Bond), and a group in which a plurality of these are linked.

  Examples of the divalent hydrocarbon group include a linear or branched alkylene group having 1 to 18 carbon atoms, a divalent alicyclic hydrocarbon group, and the like. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene group, 1,3-cyclopentylene group, cyclopentylidene group, 1,2-cyclohexylene group, 1,3-cyclohexene group. And divalent cycloalkylene groups (including cycloalkylidene groups) such as a silene group, a 1,4-cyclohexylene group, and a cyclohexylidene group.

  The linking group X is preferably a linking group containing an oxygen atom. Examples of such a linking group X include —CO— (carbonyl group), —O—CO—O— (carbonate group), —COO— (ester group), —O— (ether group), —CONH—. (Amide group), a group in which a plurality of these groups are linked, and a group in which one or more of these groups are linked to one or more of divalent hydrocarbon groups. Examples of the divalent hydrocarbon group include those exemplified above.

  As the alicyclic epoxy compound represented by the general formula (I), for example, commercial products such as trade names “Celoxide 2021P” and “Celoxide 2081” (both manufactured by Daicel Corporation) can be used. . In addition, as a compound in which X is a single bond in the alicyclic epoxy compound represented by the general formula (I), for example, a commercially available product such as a trade name “Celoxide 8000” (manufactured by Daicel Corporation) may be used. it can.

  An alicyclic epoxy compound (A) can be used individually or in combination of 2 or more types. Among these, as the alicyclic epoxy compound (A), 3 ′, 4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name “Celoxide 2021P”) and ε-caprolactone modified 3 ′, 4 ′ It is particularly preferred to use at least one of epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

  The proportion of the amount of the alicyclic epoxy compound (A) in the total amount of the alicyclic epoxy compound (A) and the polyol compound (B) is preferably in the range of 50 to 80% by mass, 70 to More preferably, it is in the range of 75% by mass. When this ratio is too small, the crosslink density in the cured product of the resin composition is low, and high heat resistance may not be obtained. When this ratio is too large, the cured product of the resin composition becomes hard and brittle, and high flexibility may not be obtained.

[Polyol compound (B)]
By including the polyol compound (B) in the resin composition, a cured product having high flexibility can be formed.

  The polyol compound (B) is a polymer (oligomer or polymer) having two or more hydroxyl groups in one molecule and having a number average molecular weight of, for example, 200 or more. Examples of the polyol compound (B) include polyether polyol, polyester polyol, and polycarbonate polyol. In addition, a polyol compound can be used individually or in combination of 2 or more types.

  The hydroxyl group (two or more hydroxyl groups) contained in the polyol compound (B) may be an alcoholic hydroxyl group or a phenolic hydroxyl group. Moreover, the number of the hydroxyl groups which a polyol compound (B) has in 1 molecule should just be two or more, and is not specifically limited.

  The position of the hydroxyl group (two or more hydroxyl groups) in the polyol compound (B) is not particularly limited, but is present at at least one end of the polyol molecule (end of the polymer main chain) from the viewpoint of reactivity with the curing agent. It is preferable to be present at least at both ends of the polyol molecule.

  The polyol compound (B) is only required to form a liquid resin composition after being blended with other components, and may itself be a solid or a liquid.

  Although the number average molecular weight of a polyol compound (B) is not specifically limited, For example, it is 200 or more, it is preferable to exist in the range of 200-100000, and it is more preferable to exist in the range of 300-1000. If the number average molecular weight is too small, the film, which is a cured product of the resin composition, may be broken or cracked when it is peeled from the substrate on which the resin composition is applied. On the other hand, if the number average molecular weight is too large, the polyol compound may precipitate in the liquid resin composition, or the polyol compound may not be dissolved in other components. In addition, the number average molecular weight of a polyol compound (B) means the number average molecular weight of standard polystyrene conversion measured by gel permeation chromatography (GPC).

  The polyol compound (B) preferably has a hydroxyl value in the range of 190 to 550 KOHmg / g. If the hydroxyl value is too small, the crosslink density in the cured product of the resin composition is low, and high heat resistance may not be obtained. When the hydroxyl value is too large, the amount of the hydroxyl group becomes excessive with respect to the amount of the epoxy group, and a floating monomer that does not contribute to the reaction may be generated in the cured product. As a result, the thermogravimetric change is increased, which may cause a decrease in heat resistance and an increase in hygroscopicity.

  Examples of the polyol compound (B) include a polyester polyol (including a polyester polyol oligomer) having an ester skeleton (polyester skeleton) in the molecule, and a polyether polyol (polyether polyol) having an ether skeleton (polyether skeleton) in the molecule. Oligomers), and polycarbonate polyols (including polycarbonate polyol oligomers) having a carbonate skeleton (polycarbonate skeleton) in the molecule. The polyol compound (B) includes other compounds such as a phenoxy resin and an epoxy equivalent of 1000 g / eq. Also included are bisphenol-type polymer epoxy resins exceeding the above, polybutadienes having a hydroxyl group, and acrylic polyols.

  Examples of the polyester polyol include polyester polyol obtained by condensation polymerization (for example, transesterification) of polyol and polycarboxylic acid (polybasic acid) or hydroxycarboxylic acid, and ring-opening polymerization of lactones. A polyester polyol etc. are mentioned.

  Examples of the polyol used in the condensation polymerization for obtaining the polyester polyol include ethylene glycol, diethylene glycol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,3-propanediol, 1, 4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2, 3,5-trimethyl-1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2,6- Hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, 1,2-dimethylol Hexane, 1,3-dimethylolcyclohexane, 1,4-dimethylolcyclohexane, 1,12-dodecanediol, polybutadienediol, neopentyl glycol, tetramethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1 , 3-dihydroxyacetone, hexylene glycol, 1,2,6-hexanetriol, ditrimethylolpropane, mannitol, sorbitol, and pentaerythritol.

  Examples of the polycarboxylic acid used in the condensation polymerization for obtaining the polyester polyol include oxalic acid, adipic acid, sebacic acid, fumaric acid, malonic acid, succinic acid, glutaric acid, azelaic acid, citric acid, 2,6 Naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, citraconic acid, 1,10-decanedicarboxylic acid, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, Examples include pyromellitic anhydride and trimellitic anhydride.

  Examples of the hydroxycarboxylic acid used in the condensation polymerization for obtaining the polyester polyol include lactic acid, malic acid, glycolic acid, dimethylolpropionic acid, and dimethylolbutanoic acid.

  Examples of the lactones used in the ring-opening polymerization for obtaining the polyester polyol include ε-caprolactone, δ-valerolactone, and γ-butyrolactone.

  Examples of the polyester polyol include, for example, trade names "Placcel 205", "Placcel 205H", "Placcel 205U", "Placcel 205BA", "Placcel 208", "Placcel 210", "Placcel 210CP", “Plaxel 212”, “Plaxel 212CP”, “Plaxel 220”, “Plaxel 220CPB”, “Plaxel 220NP1”, “Plaxel 220BA”, “Plaxel 220ED”, “Plaxel 220EB”, “Plaxel 220EC”, “Plaxel 230”, “Plaxel 230CP”, “Plaxel 240”, “Plaxel 240CP”, “Plaxel 210N”, “Plaxel 220N”, “Plaxel L205AL”, “Plaxel L208A” ”,“ Plaxel L212AL ”,“ Plaxel L220AL ”,“ Plaxel L230AL ”,“ Plaxel 305 ”,“ Plaxel 308 ”,“ Plaxel 312 ”,“ Plaxel L312AL ”,“ Plaxel 320 ”,“ Placcel L320AL ”,“ Plaxel L330AL ” ”,“ Placcel 410 ”,“ Placcel 410D ”,“ Placcel 610 ”,“ Placcel P3403 ”, and“ Placcel CDE9P ”(all manufactured by Daicel Corporation) can be used.

  Examples of the polyether polyol include polyether polyols obtained by addition reaction of cyclic ether compounds to polyols, and polyether polyols obtained by ring-opening polymerization of alkylene oxide.

  More specifically, examples of the polyether polyol include ethylene glycol, diethylene glycol, 1,2-propanediol (propylene glycol), 2-methyl-1,3-propanediol, 1,3-propanediol, , 4-butanediol (tetramethylene glycol), 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5 -Pentanediol, 2,3,5-trimethyl-1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexane Diol, 2,6-hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol 1,2-dimethylolcyclohexane, 1,3-dimethylolcyclohexane, 1,4-dimethylolcyclohexane, 1,12-dodecanediol, polybutadienediol, neopentyl glycol, dipropylene glycol, glycerin, trimethylolpropane, 1 Multimers of polyols such as 1,3-dihydroxyacetone, hexylene glycol, 1,2,6-hexanetriol, ditrimethylolpropane, mannitol, sorbitol, and pentaerythritol; the above polyols, ethylene oxide, propylene oxide, 1 Adducts with alkylene oxides such as 1,2-butylene oxide, 1,3-butylene oxide, 2,3-butylene oxide, tetrahydrofuran, and epichlorohydrin; Ring-opened polymer of a cyclic ether such as tetrahydrofuran (for example, poly tetramethylene glycol) and the like.

  Examples of the polyether polyol include trade name “PEP-101” (manufactured by Freund Sangyo Co., Ltd.), trade names “Adeka Pluronic L”, “Adeka Pluronic P”, “Adeka Pluronic F”, “Adeka Pluronic R”. , “Adeka Pluronic TR”, and “Adeka PEG” (all manufactured by Adeka Corporation); trade names “PEG # 1000”, “PEG # 1500”, and “PEG # 11000” (all NOF Corporation) Product names “New Pole PE-34”, “New Pole PE-61”, “New Pole PE-78”, “New Pole PE-108”, “PEG-200”, “PEG-600”, “ “PEG-2000”, “PEG-6000”, “PEG-10000”, and “PEG-20000” (all manufactured by Sanyo Chemical Industries, Ltd.); Name "PTMG1000", "PTMG1800", and "PTMG2000" (both manufactured by Mitsubishi Chemical Corp.); can be used as well as "PTMG prepolymer" (manufactured by Mitsubishi Plastics Inc.), and commercial products.

  The polycarbonate polyol is a polycarbonate having two or more hydroxyl groups in the molecule. Among these, the polycarbonate polyol is preferably a polycarbonate diol having two terminal hydroxyl groups in the molecule.

  The above polycarbonate polyol is the same as the method for producing a normal polycarbonate polyol, or a phosgene method, or a carbonate exchange reaction using a dialkyl carbonate or diphenyl carbonate such as dimethyl carbonate and diethyl carbonate (Japanese Patent Laid-Open No. 62-187725, special feature). No. 2-175721, JP-A-2-49025, JP-A-3-220233, JP-A-3-252420 and the like. Since the carbonate bond in the polycarbonate polyol is not easily decomposed by heat, the cured product of the resin composition containing the polycarbonate polyol exhibits excellent stability even under high temperature and high humidity.

  Examples of the polyol used in the carbonate exchange reaction together with the dialkyl carbonate or diphenyl carbonate include 1,6-hexanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,3-butane. Diol, 2,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,8-octanediol, 1,9-nonanediol, 1 , 12-dodecanediol, butadiene diol, neopentyl glycol, tetramethylene glycol, propylene glycol, and propylene glycol.

  Examples of the polycarbonate polyol include, for example, trade names “Placcel CD205PL”, “Plaxel CD205HL”, “Plaxel CD210PL”, “Plaxel CD210HL”, “Plaxel CD220PL”, and “Plaxel CD220HL” (all manufactured by Daicel Corporation); Product names “UH-CARB50”, “UH-CARB100”, “UH-CARB300”, “UH-CARB90 (1/3)”, “UH-CARB90 (1/1)”, and “UC-CARB100” (whichever As well as product names “PCDL T4671,” “PCDL T4672,” “PCDL T5650J,” “PCDL T5651,” and “PCDL T5652” (all manufactured by Asahi Kasei Chemicals Corporation). Use a commercial product Can.

  Examples of polyols other than the polyether polyol, polyester polyol, and polycarbonate polyol include trade names “YP-50”, “YP-50S”, “YP-55U”, “YP-70”, “ZX-1356”. 2 ”,“ YPB-43C ”,“ YPB-43M ”,“ FX-316 ”,“ FX-310T40 ”,“ FX-280S ”,“ FX-293 ”,“ YPS-007A30 ”, and“ TX-1016 ” (All manufactured by Nippon Steel Chemical Co., Ltd.) and phenoxy resins such as trade names “jER1256”, “jER4250”, and “jER4275” (all manufactured by Mitsubishi Chemical Corporation); trade name “Epototo YD- 014 "," Epototo YD-017 "," Epototo YD-019 "," Epototo YD-020G "," Epototo YD " 904 ”,“ Epototo YD-907 ”, and“ Epototo YD-6020 ”(all manufactured by Nippon Steel Chemical Co., Ltd.), trade names“ jER1007 ”,“ jER1009 ”,“ jER1010 ”,“ jER1005F ”,“ Epoxy equivalents of 1000 g / eq., such as “jER1009F”, “jER1006FS”, and “jER1007FS” (all manufactured by Mitsubishi Chemical Corporation). Bisphenol type polymer epoxy resin exceeding the product name; “Poly bd R-45HT”, “Poly bd R-15HT”, “Poly ip”, and “KRASOL” (all manufactured by Idemitsu Kosan Co., Ltd.) Polybutadienes having hydroxyl groups such as “α-ω polybutadiene glycol G-1000”, “α-ω polybutadiene glycol G-2000”, and “α-ω polybutadiene glycol G-3000” (all manufactured by Nippon Soda Co., Ltd.) And trade names “Hitaroid 3903”, “Hitaroid 3904”, “Hitaroid 3905”, “Hitaroid 6500”, “Hitaroid 6500B”, and “Hitaroid 3018X” (all manufactured by Hitachi Chemical Co., Ltd.) "Acridic DL-1537", "Acridic BL-616 ”,“ Acridic AL-1157 ”,“ Acridic A-322 ”,“ Acridic A-817 ”,“ Acridic A-870 ”,“ Acridic A-859-B ”,“ Acridic A-829 ” ", And" Acridick A-49-394-IM "(all manufactured by DIC Corporation), trade names" Dianar SR-1346 "," Dianar SR-1237 ", and" Dianar AS-1139 " Commercial products such as acrylic polyols (all manufactured by Mitsubishi Rayon Co., Ltd.) can be used.

  In addition, the said polyol compound can be used individually or in combination of 2 or more types. The polyol compound (B) is a polyester polyol, for example, polycaprolactone triol such as trade names “Placcel 305” and “Placcel 308” (both manufactured by Daicel Corporation), and a trade name “Placcel CD205PL” (Daicel Corporation). Particularly preferred is at least one of carbonate diols such as

  The proportion of the amount of the polyol compound (B) in the total amount of the alicyclic epoxy compound (A) and the polyol compound (B) is preferably in the range of 20 to 50% by mass, and 25 to 30% by mass. It is more preferable that it is in the range. If this ratio is too small, the cured product of the resin composition becomes hard and brittle, and high flexibility may not be obtained. If this ratio is too large, the crosslink density in the cured product of the resin composition will be low, the amount of hydroxyl groups will be excessive relative to the amount of epoxy groups, and the resin composition may not be sufficiently cured.

[Acid generator (C)]
The acid generator (C) has a function of initiating polymerization of the compound having an epoxy group in the resin composition. As the acid generator (C), a cationic polymerization initiator that generates cationic species by performing ionizing radiation irradiation such as ultraviolet irradiation or heat treatment to initiate polymerization of the alicyclic epoxy compound (A) is preferable. An acid generator (C) can be used individually or in combination of 2 or more types.

  Examples of cationic polymerization initiators that generate cationic species upon irradiation with ionizing radiation include hexafluoroantimonate salts, pentafluorohydroxyantimonate salts, hexafluorophosphate salts, hexafluoroarsenate salts, triallylsulfonium salts and derivatives thereof, In addition, diallyl iodonium salts and derivatives thereof may be mentioned.

Examples of triallylsulfonium salts and derivatives thereof include triallylsulfonium hexafluorophosphate salts and derivatives thereof, and triallylsulfonium hexafluoroantimonate salts and derivatives thereof.
Examples of diallyl iodonium salts and derivatives thereof include diallyl iodonium hexafluorophosphate salts and derivatives thereof, and diallyl iodonium tetrafluoroborate salts and derivatives thereof.
These cationic polymerization initiators (cationic catalysts) can be used alone or in combination of two or more.

  As such a cationic polymerization initiator, for example, trade name “UVACURE1590” (manufactured by Daicel Cytec Co., Ltd.); trade names “CD-1010”, “CD-1011”, and “CD-1012” (all Product name “Irgacure 264” and “Irgacure 250” (both manufactured by Ciba Japan Co., Ltd.); Product name “CIT-1682” (produced by Nippon Soda Co., Ltd.); Product name “CPI- 101A "," CPI-100P "," CPI-210S ", and" CPI-110A "(all manufactured by Sun Apro Co., Ltd.); trade names" Adekaoptomer SP-170 "," Adekaoptomer SP-172 " , And “Adekaoptomer SP-150” (both manufactured by ADEKA Corporation); and trade name “Silico Lease UV CATA211” Commercial products such as Kawa Chemical Co., Ltd.) can be used. Preferably, trade names “SP-170” and “SP-172” (both manufactured by ADEKA Corporation) and trade names “CPI-210S”, “CPI-101A” and “CPI-110A” (both 1 or more of Sun Apro Co., Ltd.

  Examples of the cationic polymerization initiator that generates cationic species by performing heat treatment include aryldiazonium salts, aryliodonium salts, arylsulfonium salts, and allene-ion complexes.

  Examples of such a cationic polymerization initiator include trade names “PP-33”, “CP-66”, and “CP-77” (all manufactured by ADEKA Corporation); trade names “FC-509” ( Trade name “UVE1014” (manufactured by GE Corp.); trade names “Sun-Aid SI-60L”, “Sun-Aid SI-80L”, “Sun-Aid SI-100L”, “Sun-Aid SI-” 110L "and" Sun-Aid SI-150L "(both manufactured by Sanshin Chemical Industry Co., Ltd.); and a commercial name such as" CG-24-61 "(manufactured by Ciba Japan Co., Ltd.) can be used. .

  Furthermore, a chelate compound of a metal such as aluminum or titanium and a acetoacetate or diketone compound and a silanol such as triphenylsilanol, or a chelate compound of a metal such as aluminum or titanium and acetoacetate or diketone and bisphenol S Compounds with phenols such as can also be used as the cationic polymerization initiator.

  The amount of the acid generator (C) is in the range of 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the total amount of the alicyclic epoxy compound (A) and the polyol compound (B). Is preferable, and it is more preferable to be in the range of 0.05 to 0.1 parts by mass. If the amount of the acid generator (C) is too small, the crosslink density in the cured product of the resin composition becomes small, and high heat resistance may not be obtained. If the amount of the acid generator (C) is too large, a cured product having high transparency may not be obtained.

[Other components (D)]
The resin composition can further contain another component (D) as necessary.
For example, the resin composition may further contain a cation reactive compound such as a vinyl ether compound for adjusting the curability. Moreover, the resin composition may further contain an oxetane compound in order to lower the viscosity and adjust the reaction rate. The resin composition may further contain a radical reactive compound for adjusting the adhesion between the substrate and a layer formed by curing the resin composition.

  The resin composition includes other components, such as antioxidants, ultraviolet absorbers, light stabilizers (HALS, etc.), matting agents (silica, glass powder, metal oxides, etc.), colorants (dyes, pigments, etc.), Light diffusing agent, low shrinkage agent, anti-settling agent, antifoaming agent, antistatic agent, anti-fogging agent, dispersant, thickener, anti-sagging agent, drying agent, leveling agent, coupling agent, adhesion promoter, prevention Rust pigment, heat stabilizer, film substance modifier, slip agent, scratch agent, plasticizer, antibacterial agent, antifungal agent, antifouling agent, flame retardant, polymerization inhibitor, photopolymerization accelerator, sensitizer, One or more additives such as a thermal initiator (thermal cationic polymerization initiator, thermal radical polymerization initiator) and a release agent may be further contained.

  The amount of the component (D) is preferably 10 parts by mass or less, preferably 1 part by mass or less, with respect to 100 parts by mass of the total amount of the alicyclic epoxy compound (A) and the polyol compound (B). Is more preferable.

<Preparation of resin composition>
Said resin composition is obtained by mixing the component mentioned above uniformly. For this mixing, for example, although not particularly limited, a stirrer such as a disper mixer, an ultra mixer, a homogenizer, and a planetary stirring deaerator can be used. This mixing is preferably performed in an environment where no ionizing radiation is irradiated in order to prevent activation of the acid generator.

<Manufacture of transparent magnetic sheet>
The transparent magnetic sheet 10 is manufactured by the following method, for example.
First, the transparent substrate 1 is prepared. Also, a coating solution that is a raw material for the transparent magnetic layer 2 is prepared. The coating liquid can be obtained, for example, by dispersing the magnetic particles 2M in the resin composition described above. At this stage, the magnetic particles 2M are not magnetized. Therefore, the magnetic particles 2M can be dispersed in the resin composition by a general dispersion method.

  Next, this coating solution is applied onto the transparent substrate 1. Thereby, the coating film which consists of a coating liquid is formed. For coating the coating liquid, for example, die coating method, dipping method, method using wire bar, roll coating method, gravure coating method, reverse coating method, air knife coating method, comma coating method, curtain method, screen printing method, Known methods such as a spray coating method and a gravure offset method can be used. Moreover, when it is necessary to supply the coating liquid accommodated in the container to a coating part such as a die head at a constant flow rate, for example, a supply device such as a mono pump, a diaphragm pump, and a gear pump can be used.

  Subsequently, the coating film is irradiated with ionizing radiation. Here, the term “ionizing radiation” refers to a high-energy radiation that can generate an acid in the resin composition by decomposing (ionizing) components contained in the resin composition, specifically, an acid generator, for example, X Means line or ultraviolet light. As the ionizing radiation, ultraviolet rays are typically used.

  When the coating film is irradiated with ionizing radiation, the acid generator contained in the resin composition is activated. That is, the acid generator is decomposed (ionized) to generate an acid in the resin composition. The acid serves as a catalyst for promoting polymerization and crosslinking in the resin composition. Accordingly, the resin composition undergoes polymerization and crosslinking by irradiation with ionizing radiation, and as a result, the coating is cured.

  Then, if necessary, post-baking is performed on the coating film irradiated with ionizing radiation. By performing post-baking, the above reaction in the resin composition is completed. When post-baking is performed, the crosslink density in the transparent magnetic layer 2 can be increased, and the heat resistance is increased. For post-baking, for example, heating methods such as hot air drying, hot roll drying, high-frequency irradiation, and infrared irradiation can be used alone or in combination of two or more.

Thereafter, the magnetic particles 2M are magnetized. A known method can be used for this magnetization.
The transparent magnetic sheet 10 is obtained as described above.

<Application example of transparent magnetic sheet>
The above-described transparent magnetic sheet 10 can be used as a recording sheet used for printing, for example. This will be described with reference to FIG.

FIG. 2 is a cross-sectional view schematically showing an example of a printed matter obtained using the transparent magnetic sheet shown in FIG.
A printed matter 100 shown in FIG. 2 includes a transparent magnetic sheet 10 and a printed layer 20. The print layer 20 is supported by the transparent magnetic sheet 10. The print layer 20 displays information such as images and characters, for example.

  This printed matter 100 is magnetically attracted to an article made of a soft magnetic material such as an iron plate. Therefore, the printed material 100 can be easily installed on a bulletin board or whiteboard, or removed from the bulletin board or whiteboard.

  In addition, the transparent magnetic sheet 10 included in the printed material 100 can be magnetically attracted by the transparent magnetic layer 2 in which the magnetic particles 2M are uniformly dispersed in the transparent resin 2R. Therefore, the transparent magnetic sheet 10 can be formed with a uniform thickness, unlike a recording sheet including a rubber magnet tape. Therefore, the printing layer 20 can be easily formed using a printer or the like.

  Further, the transparent magnetic sheet 10 included in the printed material 100 does not include a rubber magnet tape or a belt-like magnet layer but includes the transparent magnetic layer 2. The transparent magnetic layer 2 can have uniform optical properties throughout. Therefore, in this transparent magnetic sheet 10, unlike the case where a rubber magnet tape or a belt-like magnet layer is used, the appearance is not impaired by a member for imparting a magnetic attractive force.

  In the printed matter 100, the printed layer 20 covers only a part of the main surface of the transparent magnetic sheet 10. And as above-mentioned, the transparent magnetic sheet 10 is excellent in transparency. Therefore, in the portion corresponding to the other region of the printed material 100, the article behind can be seen through. That is, the transparent magnetic sheet 10 is not conspicuous. Therefore, according to this printed matter 100, it is possible to minimize the influence of the transparent magnetic sheet 10 on the image or ordinary display by the printed layer 20.

  The transparent magnetic sheet 10 can also be used for other purposes. For example, the transparent magnetic sheet 10 can be used as a protective sheet for protecting an article such as a vehicle body.

  Examples of the present invention will be described below. In addition, the following description is for making an understanding of this invention easy, and is not intending to limit to the content described here.

<Example 1>
A transparent magnetic sheet 10 shown in FIG. 1 was produced by the following method.
First, a coating solution having the following composition was prepared.
Main agent (Celoxide P2021P; manufactured by Daicel Corporation): 70 parts by mass Added resin (Placcel CD205PL; manufactured by Daicel Corporation): 30 parts by mass Acid generator (SP-170; manufactured by ADEKA Corporation): 0.5 mass Part Barium ferrite (633602; manufactured by Sigma-Aldrich): 1 part by mass In this coating solution, the above-described components are put into a bead mill to sufficiently disperse the magnetic particles 2M, and then the vacuum depressurization is performed on the dispersion. It was prepared by defoaming with a foam machine. In addition, the average particle diameter of the barium ferrite used here was 50 micrometers or less.

Next, the transparent magnetic layer 2 was formed on the transparent substrate 1 using a roll-to-roll die coater. Specifically, a polyethylene terephthalate film was used as the transparent substrate 1. The transparent substrate 1 was conveyed at a speed of 10 m / min. The coating liquid was supplied from the storage tank to the die head using a diaphragm pump (Smooth Flow (registered trademark) pump; manufactured by Takumina Co., Ltd.) so that the transparent magnetic layer 2 had a thickness of 250 μm. The coating film made of the coating solution was irradiated with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² . The exposed coating film was post-baked for 180 seconds using an oven set at a temperature of 150 ° C.

Thereafter, the magnetic particles M were magnetized. An oil condenser type magnetizer was used for this magnetization.
The transparent magnetic sheet 10 shown in FIG. 1 was obtained as described above.

<Example 2>
A transparent magnetic sheet 10 shown in FIG. 1 was produced by the same method as in Example 1 except that the amount of barium ferrite was 5 parts by mass with respect to 100 parts by mass in total of the main agent and additives.

<Example 3>
A transparent magnetic sheet 10 shown in FIG. 1 was produced in the same manner as in Example 1 except that the amount of barium ferrite was changed to 0.1 parts by mass with respect to 100 parts by mass in total of the main agent and additives.

<Example 4>
A transparent magnetic sheet 10 shown in FIG. 1 was produced by the same method as in Example 1 except that barium ferrite having an average particle diameter of 1 μm was used.

<Comparative Example 1>
A transparent magnetic sheet 10 shown in FIG. 1 was produced in the same manner as in Example 1 except that the amount of barium ferrite was 10 parts by mass with respect to 100 parts by mass of the main agent and the additive.

<Comparative example 2>
A transparent magnetic sheet 10 shown in FIG. 1 was produced in the same manner as in Example 1 except that the amount of barium ferrite was 0.05 parts by mass with respect to 100 parts by mass in total of the main agent and additives.

<Comparative Example 3>
A transparent magnetic sheet 10 shown in FIG. 1 was produced by the same method as in Example 1 except that barium ferrite having an average particle diameter of 2 μm was used.

<Comparative Example 4>
A transparent magnetic sheet 10 shown in FIG. 1 was produced in the same manner as in Example 1 except that bisphenol A type epoxy resin was used as the main agent. The cured product of bisphenol A type epoxy resin was opaque.

<Evaluation>
For each of the transparent magnetic sheets 10 according to Examples 1 to 3 and Comparative Examples 1 to 5, the total light transmittance and the average particle diameter of the magnetic particles 2M were measured by the method described above. A sample having a total light transmittance of 85% or more was evaluated as “◎”, a sample having a total light transmittance of 50% or more and less than 85% was evaluated as “◯”, and the total light transmittance was 30%. Those that were less than 50% were evaluated as “Δ”, and those that had a total light transmittance of less than 30% were evaluated as “x”.

Further, each of the transparent magnetic sheets 10 according to Examples 1 to 3 and Comparative Examples 1 to 5 was examined for magnetic attraction force and presence / absence of appearance abnormality. Regarding the magnetic attraction force, a stainless steel plate made of SUS430 and having a thickness of 5 mm is installed so that its main surface is parallel to the direction of gravity. Those that were magnetically adsorbed were evaluated as “◯”, and those that were not magnetically adsorbed to the stainless steel plate were evaluated as “x”. The presence or absence of appearance abnormality was examined by observing the transparent magnetic sheet 10 with the naked eye.
The results are summarized in Table 1 below.

  As is clear from the comparison between Examples 1 to 3 and Comparative Example 1, when the proportion of the magnetic particles 2M in the transparent magnetic layer 2 was increased, the total light transmittance was lowered. As is clear from the comparison between Examples 1 to 3 and Comparative Example 2, when the proportion of the magnetic particles 2M in the transparent magnetic layer 2 was reduced, the magnetic attractive force was insufficient.

  As is clear from the comparison between Examples 1 and 4 and Comparative Example 3, when the average particle diameter of the magnetic particles 2M was increased, the total light transmittance was lowered. When the average particle diameter was 2 μm, aggregates of the magnetic particles 2M were observed with the naked eye.

  Furthermore, as apparent from the comparison between Example 1 and Comparative Example 4, when an opaque resin was used instead of the transparent resin 2R, a sufficient total light transmittance could not be achieved.

  DESCRIPTION OF SYMBOLS 1 ... Transparent base material, 2 ... Transparent magnetic layer, 2M ... Magnetic substance particle, 2R ... Transparent resin, 10 ... Transparent magnetic sheet, 20 ... Print layer, 100 ... Printed matter.

Claims (6)

  A transparent magnetic layer comprising a transparent resin and magnetic particles dispersed in the transparent resin is provided, the average particle diameter of the magnetic particles is 1 μm or less, and the ratio of the magnetic particles in the transparent magnetic layer Is a transparent magnetic sheet in the range of 0.1 to 5% by mass.   The transparent magnetic sheet according to claim 1, further comprising a transparent substrate that supports the transparent magnetic layer.   The transparent magnetic sheet according to claim 1 or 2, wherein an average particle diameter of the magnetic particles is 100 nm or less.   The transparent magnetic sheet according to any one of claims 1 to 3, wherein the total light transmittance is 30% or more and less than 85%.   The transparent magnetic sheet according to any one of claims 1 to 4, wherein the transparent resin is a cured product of a resin composition containing an alicyclic epoxy compound (A) and a polyol compound (B).   A printed matter comprising the transparent magnetic sheet according to any one of claims 1 to 5 and a print layer supported by the transparent magnetic sheet.