JPH0677174B2 - Hologram transfer sheet and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a hologram transfer sheet and a method for producing the same, and more specifically, on a surface of a card such as a credit card or a bank card, a book cover, a record jacket, or the like. The present invention relates to a hologram transfer sheet suitable for providing a hologram by a transfer method and a method for manufacturing the hologram transfer sheet.

[Technical background of the invention and its problems]

Holography is a new technique for recording the wavefront of light from an object, and a hologram produced by this technique can reproduce a stereoscopic image and also enables multiple recording. Further, as one method of recording a hologram, interference fringes corresponding to the wavefront of light from an object can be recorded on the surface of the material in a concavo-convex pattern, and this hologram can be easily mass-produced.

Such holograms, such as credit cards,
When provided on cards such as bank cards, it is possible to obtain cards that are beautiful and novel and that are difficult to forge and alter the cards themselves. Further, when it is provided on the cover of a book, a record jacket, clothes, etc., a product with beauty and novelty can be obtained.

In order to provide holograms on the surface of cards, book covers, record jackets, etc., it is possible to record interference fringes corresponding to the wavefront of light from an object in the shape of an uneven pattern and duplicate it in large quantities. This is necessary, and in this case, it is necessary to efficiently provide this uneven pattern on cards and the like.

Conventionally, in order to provide holograms on the surface of cards, book covers, record jackets, etc., duplicate holograms have been attached to the surfaces of cards and the like. However, according to this method, there is a problem in that it takes a lot of time and effort for sticking and is not suitable for mass production. Therefore, it has been required to efficiently provide the hologram on the surface of cards and the like.

By the way, a magnetic recording layer is extremely widely used as a recording layer in cards, but this magnetic recording layer is generally provided on a card substrate by a thermal transfer method. Therefore, if the hologram can be provided on the surface of the card by the thermal transfer method, there is an advantage that the hologram can be efficiently provided on the surface of the card by existing equipment.

By the way, when a hologram is transferred onto a substrate such as a card paper by a thermal transfer method, since the hologram layer is generally formed of a thermoplastic resin, heat is applied to the hologram layer during the transfer, and at this time, the hologram layer is transferred from the object. There was a serious problem that the uneven pattern, which is an interference fringe corresponding to the wavefront of the light, disappeared partly.

[Object of the Invention]

The present invention is intended to solve the problems associated with these conventional techniques, and has the following objects.

(A) To provide a hologram transfer sheet capable of efficiently providing a hologram on the surface of cards, book covers, record jackets, etc. by a thermal transfer method, and a method for producing the same.

(B) Since the hologram can be provided on the surface of the card by the thermal transfer method, the existing equipment can be used almost as it is, and at the time of the thermal transfer of the hologram layer, the uneven pattern which is the interference fringe corresponding to the wavefront of the light from the object is formed. To provide a hologram transfer sheet having an advantage of being thermally transferred without disappearing, and a method for manufacturing the hologram transfer sheet.

[Outline of Invention]

The analog transfer sheet according to the present invention is a release layer on a substrate film, a hologram layer on the surface of which interference fringes corresponding to the wavefront of light from an object are formed in a concave-convex shape, a reflective metal vapor deposition layer, and a heat-sensitive layer. In the hologram transfer sheet in which the adhesive layer is provided in this order, the hologram layer is made of a cured ultraviolet curable resin or electron beam curable resin. If necessary, a peeling layer or an overprint layer or both may be provided between the substrate film and the hologram layer, and an anchor layer is provided between the metal vapor deposition layer and the adhesive layer. It may be.

Further, the method for producing a hologram transfer sheet according to the present invention, a release layer is formed on a substrate film, and a solid ultraviolet curable resin or electron beam curable resin layer having thermoformability is formed on the release layer. After preparing the hologram forming film, the hologram forming film and the hologram original plate on the surface of which the interference fringes corresponding to the wavefront of the light from the object are formed in an uneven shape, the resin is heated. Under the conditions, the resin of the hologram forming film is pressed into contact with the hologram original plate so as to be in contact,
Forming concavities and convexities on the resin, irradiating the hologram forming film with ultraviolet rays or electron beams to cure the resin, and then depositing a reflective metal thin film on the resin surface on which the concavities and convexities are formed, and then A heat-sensitive adhesive layer is provided on the reflective metal thin film layer.

A release layer, an overprint layer, or both may be provided between the base film and the resin, if necessary. In the production method of the preferred embodiment of the hologram transfer sheet according to the present invention, a hologram forming film in which an ultraviolet curable resin or an electron beam curable resin is provided on a substrate film, and the surface corresponds to the wavefront of light from an object. Interference fringes and a hologram master plate formed as an uneven pattern, the ultraviolet curing resin or electron beam curing resin of the film so as to contact the hologram master plate, if necessary under pressure contact with the resin under heating conditions After forming the irregularities, the hologram forming film is irradiated with ultraviolet rays or electron beams to cure the resin, and then a reflective metal thin film layer is applied to the surface of the resin on which the irregularities are formed. It is characterized in that an adhesive layer is provided on the thin film layer. Either a release layer or an overprint layer or both may be provided between the base film and the resin, and further between the reflective metal thin film layer and the adhesive layer,
An anchor layer may be provided.

[Specific Description of the Invention]

 The present invention will be described below with reference to specific examples shown in the drawings.

The hologram transfer sheet 1 according to the present invention is provided with a hologram layer 3, a reflective metal thin film layer 4 and an adhesive layer 5 in this order on a base film 2 as shown in the sectional view of FIG. It has been configured. A hologram transfer sheet 1 which is another specific example has a release layer 6 and an overprint layer 7 between a base film 2 and a hologram layer 3 as shown in a sectional view of FIG. An anchor layer 8 is provided between the reflective metal thin film layer 4 and the adhesive layer 5 in this order.

As the base film 2, any film-shaped material can be used. Specifically, polymer films such as polyethylene terephthalate, polyimide, polymethyl methacrylate, polystyrene, polyvinyl butyral, and polycarbonate, synthetic paper, metal films such as iron, and the like can be used. Also, a laminate of these may be used. The film thickness of this base film is 1 to 200 μm, preferably 10 to 50 μm.
It is preferably μm.

The hologram layer 3 is made of a thermosetting resin that is cured by ultraviolet rays or electron beams or a thermosetting resin that has a thermoforming property, and a hologram is formed on the surface of the resin in an uneven pattern.

As will be described later, this hologram layer 3 is formed by a duplication method using a hologram master plate on the surface of which interference fringes corresponding to the wavefront of light from an object are formed in an uneven pattern.

The thickness of the hologram layer is 0.1-50 μm, preferably 0.5-
It is preferably 5 μm.

The resin for the hologram layer that can be used in the present invention can be thermoformed at the time of molding (reproduction) of the hologram, and after the hologram is formed, that is, at the time of transfer, it is necessary that it has heat resistance enough to withstand the heat at the time of transfer. is there. As such a resin, a so-called ultraviolet curable resin, an electron beam curable resin, a thermosetting resin, a natural curable reactive resin, or the like can be used.

In the present invention, a resin having a slow curing time and curable by ultraviolet rays or electron beams is suitable.

Specifically, for example, methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate,
Butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, isoamyl acrylate, isoamyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,
2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, ethylene glycol diacrylate,
Ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane diacrylate,
Trimethylolpropane dimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate,
Dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, ethylene glycol diglycidyl ether diacrylate, ethylene glycol diglycidyl ether dimethacrylate, polyethylene glycol diglycidyl ether diacrylate, polyethylene glycol diglycidyl ether dimethacrylate, propylene glycol diglycidyl ether diacrylate Acrylate, propylene glycol diglycidyl ether dimethacrylate, polypropylene glycol diglycidyl ether diacrylate, polypropylene glycol diglycidyl ether dimethacrylate, sorbitol tetraglycyl ether tetraacrylate,
A monomer having a radically polymerizable unsaturated group such as sorbitol tetraglycidyl ether tetramethacrylate may be used.

Further, as the ultraviolet or electron beam curable resin having thermoformability, a radical unsaturated group is introduced into a polymer obtained by polymerizing or copolymerizing the following compounds (1) to (2) to (4) described below. Things are used.

Monomers having hydroxyl groups: N-methylol acrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2
-Hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, and the like.

Monomers having a carboxyl group: acrylic acid, methacrylic acid, acryloyloxyethyl monosuccinate, etc.

Monomers having epoxy groups: glycidyl methacrylate and the like.

Monomers having an aziridinyl group: 2-aziridinyl ethyl methacrylate, allyl 2-aziridinyl propionate, etc.

Monomers having amino groups: acrylamide, methacrylamide, diacetone acrylamide, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.

Monomer having sulfone group: 2-acrylamide-
2-methylpropanesulfonic acid and the like.

Monomers having isocyanate groups: 1,4-toluene diisocyanate and 2-hydroxyethyl acrylate, such as an adduct of 1 mole to 1 mole of diisocyanate and a radically polymerizable monomer having active hydrogen.

Further, in order to control the gas transition point of the above copolymer or the physical properties of the cured film, the above compound and the following monomer copolymerizable with this compound are copolymerized. It can be polymerized. Examples of such a copolymerizable monomer include methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate and t-.
Butyl acrylate, t-butyl methacrylate, isoamyl acrylate, isoamyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate and the like can be mentioned.

Next, the polymer obtained as described above is reacted by the following methods (a) to (d) to introduce a radically polymerizable unsaturated group, whereby an ultraviolet or electron beam curable resin is obtained.

(A) In the case of a polymer or copolymer of a monomer having a hydroxyl group, a monomer having a carboxyl group such as acrylic acid or methacrylic acid is subjected to a condensation reaction.

(B) In the case of a polymer or copolymer of a monomer having a carboxyl group or a sulfone group, the above-mentioned monomer having a hydroxyl group is subjected to a condensation reaction.

(C) In the case of a polymer or copolymer of a monomer having an epoxy group, an isocyanate group or an aziridinyl group, the above-mentioned monomer having a hydroxyl group or a monomer having a carboxyl group is subjected to an addition reaction.

(D) In the case of a polymer or copolymer of a monomer having a hydroxyl group or a carboxyl group, a monomer having an epoxy group, a monomer having an aziridinyl group or a diisocyanate compound and a hydroxyl group-containing acrylic acid ester unit amount The addition reaction of 1: 1 mol of the body may be carried out.

Further, the above-mentioned monomer and the thermoformable ultraviolet ray or electron beam curable resin may be mixed and used.

Further, although the above can be sufficiently cured by electron beam, when cured by ultraviolet irradiation, benzoquinone, benzoin, benzoin methyl ether as a sensitizer,
It is also possible to use benzoin ethers such as, halogenated acetophenones, and peeryls that generate radicals by irradiation with ultraviolet rays.

The reflective metal thin film layer 4 is for providing the hologram layer 3 with reflectivity, and includes Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, A.
It is formed using a metal such as l, Mg, Sb, Pb, Cd, Bi, Sn, Se, In, Ga, or Rb and an oxide or nitride thereof alone or in combination of two or more. Of these metals, Al, Cr, Ni, Ag, Au
Are particularly preferable.

In order to form such a reflective metal thin film layer on the hologram layer, a metal or an alloy as described above is prepared, and the metal or alloy is prepared by a known method such as a sputtering method, a vacuum deposition method, an ion plating method or an electroplating method. The method may be used to form a film on the hologram layer. The thickness of the reflective metal thin film layer is preferably 10 to 10,000 Å, more preferably 200 to 2,000 Å.

The adhesive layer 5 plays a role of adhering the hologram transfer sheet to cards, book covers, record jackets and the like. As the adhesive layer, those known as conventional adhesive layers such as acrylic resin, vinyl resin, polyester resin, urethane resin, amide resin, and epoxy resin can be widely used. The thickness of this adhesive layer is
The thickness is preferably 0.1 to 50 μm, more preferably 0.5 to 10 μm.

The peeling layer 6 plays a role of providing peelability between the base film 2 and the hologram layer 3, and also providing printability of the surface after transfer and protection of the hologram layer.
As the release layer 6, widely used is a known release layer such as an acrylic resin, a cellulose resin, a vinyl resin, a polyester resin, a urethane resin, an olefin resin, an amide resin, or an epoxy resin. it can. The thickness of the peeling layer is 0.05 to 10 μm, preferably 0.
It is preferably 2 to 2 μm.

When the hologram layer functions as the peeling layer, the peeling layer is basically unnecessary.

The overprint layer 7 plays a role of enhancing the adhesiveness between the hologram layer 3 and the peeling layer 6 and further imparting the durability of the hologram. As the overprint layer, those known as conventional overprint layers such as curable acrylic resin, cellulose resin, vinyl resin, polyester resin, urethane resin, olefin resin, amide resin, and epoxy resin are used. Can be widely used. The thickness of the overprint layer is preferably 0.5 to 10 μm, and more preferably 0.2 to 2 μm.

The anchor layer 8 plays a role of enhancing the adhesiveness between the reflective metal thin film layer 4 and the adhesive layer 5. As the anchor layer 8, those known as conventional anchors such as vinyl chloride-vinyl acetate copolymer, acrylic resin, urethane resin, epoxy resin, polyester resin can be widely used. The thickness of this anchor layer is 0.02-10 μm,
It is preferably 0.2 to 2 μm.

Next, a method for manufacturing the hologram transfer sheet according to the present invention will be described.

First, an ultraviolet curable resin, an electron beam curable resin or a thermosetting resin having a thermoformability, preferably an ultraviolet ray having a thermoformability, is formed on the substrate film 2 through the peeling layer 6 and the overprint layer 7, if necessary. A film for hologram formation is formed by providing a curable resin or an electron beam curable resin having thermoformability.

In order to form the hologram layer 3 with a thermoformable ultraviolet curable resin or electron beam curable resin, the hologram forming film having the ultraviolet curable resin or electron beam curable resin provided on the base film and the hologram original plate are pressed together. Then, the film is irradiated with ultraviolet rays or electron beams to cure the resin, and unevenness corresponding to the wavefront of light from the object may be formed on the surface of the resin.

Moreover, when the hologram layer 3 is formed of an ultraviolet curable resin or an electron beam curable resin, the ultraviolet curable resin and the electron beam curable resin of the types conventionally used are generally in a liquid state, and therefore, are not formed on the base film. When applied, it is extremely sticky, and therefore the conventional film for forming a hologram formed by applying a conventional ultraviolet or electron beam curable resin on the base film cannot be wound up and stored. An ultraviolet curable resin must be applied on each film to form a hologram forming film.

Therefore, in the present invention, the hologram layer 3 can be formed by the above method, but the following method is most preferable.

That is, a hologram forming film in which a thermosetting ultraviolet curable resin, electron beam curable resin or thermosetting resin is provided on a base film, and an interference fringe corresponding to the wavefront of light from an object is formed on the surface. With the hologram original plate formed in, the ultraviolet curing resin or electron beam curing resin of the film is pressed against the hologram original plate under heating conditions to form irregularities on the resin, and the original plate and the film are in close contact with each other. By irradiating the film for hologram formation with ultraviolet rays or electron beams, or by applying heat, the resin is cured to form the hologram layer 3.

According to this method, since the resin forming the hologram layer is cured, it is not necessary to repeatedly heat and cool the hologram original plate and the hologram forming film a plurality of times, and therefore the unevenness of the hologram original plate is deteriorated. Can be reduced. Further, it is possible to release the pressure contact state immediately after the hologram master and the hologram forming film are kept in a heated state and pressure-contacted to form irregularities on the film,
Therefore, the cooling step is not always necessary. Further, the hologram forming film can be wound and stored, and therefore, the hologram duplication process can be simplified and mass production becomes possible.

When heating and pressing the hologram original plate and the hologram forming film, a heating and pressing means such as a heating roll can be used.At this time, the temperature of the heating roll depends on the type of resin to be used, the material of the base film, the thickness, etc. Although it varies greatly, it is generally suitable that the temperature is 100 to 200 ° C. Further, it is preferable that the hologram original plate and the hologram forming film are pressed against each other under a pressure of 0.1 kg / cm ² or more, preferably 1 kg / cm ² or more.

At this time, in the case of irradiating with an ultraviolet ray or an electron beam, the irradiation intensity may be irradiated again after peeling the film having the irregularities of the hologram of the hologram master plate peeled from the plate, and it is possible to sufficiently cure the resin. preferable. Ultraviolet rays,
The irradiation dose of the electron beam needs to be appropriately determined according to the resin used.

In the case of forming a hologram using a thermoformable ultraviolet ray or electron beam curable resin, as in the case of using a conventional general thermoplastic resin, the hologram unevenness is formed under heat and pressure in that state. After cooling, the film may be peeled off to duplicate the hologram, and then the resin may be cured by irradiation with ultraviolet rays or electron beams.

Next, a reflective metal thin film layer is applied. As described above, this reflective metal thin film layer can be provided on the hologram layer by the ion plating method, the vacuum deposition method or the like.

Next, if necessary, an anchor layer is provided on the reflective metal thin film layer, and then an adhesive layer is provided by a coating method or the like to obtain the hologram transfer sheet according to the present invention.

〔The invention's effect〕

According to the present invention, a hologram transfer sheet having a specific structure and a method for manufacturing the same are provided, so that the following effects can be obtained.

(A) It becomes possible to efficiently provide the hologram on the surface of cards, book covers, record jackets, etc. by the thermal transfer method.

(B) When a hologram is provided on the surface of cards in particular, existing equipment can be used as it is.

(C) During thermal transfer of the hologram layer, since the hologram layer is formed of a cured resin, the fine uneven pattern of the hologram does not disappear.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 A polyethylene terephthalate film having a thickness of 25 μm as a substrate was coated with an acrylic resin (Acrynal ^# 100, an acrylic resin manufactured by Toei Kasei Co., Ltd.) as a release layer to a thickness of 0.5 μm, and further as a hologram forming resin. ,
A film for hologram formation was prepared by applying 2 μm of trimethylolpropane triacrylate.

Next, on the resin surface of this hologram forming film, as a hologram master plate, a mold in which holograms are recorded in an uneven shape is pressed and brought into close contact, and in this state, this is irradiated with an electron beam of 175 kV, 10 Mrad from the film surface. The resin for hologram formation was cured by irradiating it with an electron beam while passing it at a speed of 5 m / min.

Next, the film on which this hologram was formed was peeled off from the hologram original plate, aluminum was vacuum-deposited to a thickness of 800 Å on the surface with the irregularities formed, and on top of that, acrinal ^# 3000 (A Toei Kasei acrylic Resin) was applied to a thickness of 3 μm to prepare a transfer sheet.

The hologram transfer sheet produced in this manner was placed on the paper with the adhesive layer facing down and heated and pressed from above at 170 ° C. 50 kg / cm ^{2 to} separate the transfer sheet from the paper,
The hologram was transferred to the paper.

Example 2 As the hologram forming resin, the method described in Example 1 was used, except that 100 parts of trimethylolpropanate acrylate and 4% of Irgaquinia 184 (manufactured by Ciba-Geigy) were added as a sensitizer. A hologram forming film was prepared in the same manner, and was brought into pressure contact with the hologram master plate.

Next, from the film surface, 2m / m at a position of 10cm under the 80W / cm mercury lamp.
The hologram forming resin was cured by irradiating it with ultraviolet rays at a speed of in.

Further, in the same manner as in the method described in Example 1, vacuum evaporation of aluminum and application of an adhesive layer to prepare a hologram transfer sheet were performed, and as in Example 1, the hologram was transferred onto the paper.

Example 3 The following composition was refluxed for 6 hours for copolymerization.

Methyl methacrylate 284 parts by weight 2-hydroxyethyl 130 〃 Methacrylate ethyl acetate 1100 〃 α, α'-azobis 2 〃 isobutyronitrile Then, 0.1 parts by weight of paramethoxyphenol was added to the obtained reaction product to stop the reaction. Then, 100 parts by weight of 2-hydroxyethyl acrylate and 1 mol to 1 mol adduct of 2,4-toluene diisocyanate were added, and further 5 parts by weight of dibutyltin dilaurate was added, and the mixture was reacted at 80 ° C for 5 hours while sending dry air. Let

After the reaction solution was cooled to room temperature, 15 parts by weight of an ultraviolet sensitizer (manufactured by Irgakinia 184 Ciba Geigy) was added and uniformly dissolved to obtain an ultraviolet curable coating material.

In the same manner as in Example 1, a release layer was provided on 25 μm polyethylene terephthalate film, and then the material obtained above was uniformly applied in a dried state to a thickness of 2.5 μm to obtain a hologram forming film. This coated film is not sticky at room temperature and can be stored in a wound state.

Next, the resin surface of this coating film and the uneven surface of the mold in which the hologram is stored in the shape of unevenness are overlaid and the temperature is 150 ° C.
The mold and the coating film were brought into close contact with each other by applying heat and pressure with a nip roll at a pressure of 0 kg / cm ² .

Then, in a state where these were in close contact with each other, 10 cm under an ultraviolet lamp having an output of 80 W / cm from the film side was passed at a speed of 1 m / min to irradiate ultraviolet rays to stop the coated resin. After that, the film was peeled from the mold. Then, a transfer sheet was prepared in the same manner as in Example 1.

By using this method, a transfer sheet could be produced extremely efficiently.

[Brief description of drawings]

1 and 2 are cross-sectional views of the hologram transfer sheet according to the present invention. 1 ... Hologram transfer sheet, 2 ... Substrate film, 3 ... Hologram layer, 4 ... Reflective metal thin film layer, 5 ...
Adhesive layer.

Claims (3)

[Claims] 1. A peeling layer, a hologram layer having interference fringes corresponding to the wavefront of light from an object formed on the surface of the substrate film in the form of concavities and convexities, a reflective metal vapor deposition layer and a heat-sensitive adhesive layer. A hologram transfer sheet provided in this order, wherein the hologram layer is made of a cured ultraviolet curable resin or electron beam curable resin. 2. The hologram transfer sheet according to claim 1, further comprising an overprint layer formed between the peeling layer and the hologram layer, the overprint layer providing durability of the hologram. 3. A hologram forming film having a release layer formed on a base film, and a solid ultraviolet-curable resin or electron beam curable resin layer having thermoformability formed on the release layer is prepared. After that, with the hologram forming film,
A hologram original plate on the surface of which interference fringes corresponding to the wavefront of light from an object are formed in the shape of irregularities, and under the condition that the resin is heated, the resin of the hologram forming film is the hologram original plate. To form a concavo-convex pattern on the resin, irradiate the hologram-forming film with ultraviolet rays or an electron beam to cure the resin, and then reflect the resin surface on which the concavo-convex pattern is formed. A method for producing a hologram transfer sheet, comprising depositing a thin metal film, and then providing a heat-sensitive adhesive layer on the reflective thin metal film layer.