JPH10114159A - Iterative print recording medium and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iterative print recording medium provided with a thermally rewritable iterative print recording part excellent in durability and iterative print recording characteristics can be transferred in an arbitrary shape to an arbitrary basic material sheet, and a production method thereof. SOLUTION: An adhesive layer 6, a light reflective layer 5, and a primer layer B4 are laminated sequentially on a basic material sheet 10 through transfer or coating. An adhesive layer, a reversible thermal recording layer 9, a primer layer A8, and a protective layer 7 are then laminated sequentially thereon to form a transfer layer 12. Subsequently, the transfer layer 12 is transferred such that the adhesive layer 6 thereof is superposed on the outermost layer, i.e., the primer layer B4, including the light reflective layer 5 in order to provide an iterative print recording part 30 thus producing an iterative print recording medium 40. An ionizing radiation curing resin having elongation percentage of 5% or above is employed in the protective layer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repetitive printing recording medium rewritable by heat or the like and a method of manufacturing the same, and more particularly, to not only the entire surface of a base sheet such as a card, but also
Even in the case of a repetitive print recording medium having a configuration in which the repetitive print recording section is provided on some surfaces, the repetitive print recording medium has excellent performance without deteriorating the adhesiveness and repetitive print recording characteristics of each layer of the repetitive print recording section. And its manufacturing method.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made on the configuration and manufacturing method of a repetitive print recording medium that can be rewritten by heat. For example, as a typical configuration example,
On one side of the base sheet such as a card, a primer layer,
There is a configuration in which a light reflection layer, a primer layer, a reversible thermosensitive recording layer, a protective layer, and the like are sequentially laminated. In the case of such a configuration, most of the manufacturing methods are performed by sequentially forming each layer by a coating method and laminating the layers. Had been adopted. However, when forming each layer by the coating method, usually,
Because the repetitive print recording part is formed on the entire surface of the base sheet,
For example, it is not suitable for forming a portion in which a repetitive print recording portion is provided on a part of the surface of a base sheet such as a card and another display portion is provided on another portion by printing or the like.

In such a case, unnecessary portions of the repetitive print recording section formed on the entire surface are hidden by printing, and another necessary display content is printed thereon, so that the repetitive print recording section is formed in a window shape. It was necessary to take a method such as leaving. However, such a method is preferable because the repetitive print recording portion hidden by the printing of the unnecessary portion is completely useless, and the material that can be used for the outermost protective layer in order to obtain printability is preferable. It wasn't a way. In addition, when each layer of the repetitive print recording section is laminated on the base material sheet by a coating method, since the coating is repeatedly applied, the heat resistance,
The organic solvent resistance was required, and at the same time, the shape had to be in the form of a wound roll. Therefore, a plastic film having excellent heat resistance and organic solvent resistance such as a biaxially stretched polyethylene terephthalate film can be used, but a polyvinyl chloride sheet generally used for cards and the like has heat resistance and organic solvent resistance. Inferior, could not be used.

In order to solve such a problem, as a method of forming a repetitive print recording portion on a part of the surface of a base sheet, instead of directly coating each layer on the base sheet, for example, A method has been proposed in which a repetitive print recording unit formed in advance on another transfer film is thermally transferred to a base sheet. According to this method, the substrate sheet is heated for a short time at the time of thermal transfer, but is not heated for a long time as in the case of coating, and is not affected by an organic solvent. Therefore, a material which is relatively easily affected by heat or an organic solvent, such as a polyvinyl chloride sheet, can be used, and a repetitive print recording portion can be freely formed on a part of the surface of the base sheet. There are advantages.

[0005]

However, even when the above-described thermal transfer system is used, there are problems such as the following inadequate adhesive strength between layers and some problems regarding repetitive printing and recording characteristics. At present, sufficient performance has not always been obtained. That is, in the problem of the adhesive strength between the layers, for example, the layer configuration of the thermal transfer film for the repetitive print recording section is defined as follows: support film / release resin layer / protective layer / primer layer A / reversible thermosensitive recording layer / primer layer B / light reflection layer (metal thin film layer) / adhesive layer composed of laminated layers in order, and thermally transferred onto a base sheet by hot stamping or the like (in this case, the release surface is a release resin layer When a repetitive print recording portion is formed at the interface between the recording layer and the protective layer, usually, a metal thin film layer (e.g., a vapor-deposited film) of aluminum or the like is used as the light reflection layer for increasing the contrast of printing. And it is common to provide a primer layer or an adhesive layer on the upper and lower sides of the metal thin film layer in order to increase the adhesive strength between the layers,
Even in such a case, the adhesive strength is not always sufficient, and in a cross cut test or the like, peeling occurs mainly between the metal thin film layer and the primer layer B thereon, or during actual rewriting. In addition, there is a problem that separation occurs between the layers.

[0006] Further, depending on conditions such as a solvent at the time of coating of an adhesive layer or the like to be laminated on the light reflecting layer in the production stage of the thermal transfer film, heat at the time of drying, or heat and pressure at the next stage of the transfer. However, there is a problem in that the metal thin film layer is deteriorated, and the function as a light reflection layer (metallic luster, reflection function) is impaired, resulting in a decrease in print contrast. The present invention has been made in view of the above-described problems, and an object thereof is to provide a repetitive print recording unit in an arbitrary shape on at least a part of a surface of a base sheet such as a card. The present invention provides a repetitive print recording medium with good productivity, in which the repetitive print recording medium has good adhesiveness of each layer of the repetitive print recording section, and also has excellent performance such as repetitive print recording characteristics and durability. It is in.

[0007]

SUMMARY OF THE INVENTION In general, when manufacturing a repetitive print recording medium having a repetitive print recording portion rewritable by heat or the like provided on at least a part of the surface of a base sheet in an arbitrary shape and size. The method of providing a repetitive print recording section on a base sheet using a transfer method is the simplest and most suitable method. However, in that case, the configuration of the transfer sheet may be, for example, on a support sheet, a release resin layer, a protective layer, a primer layer A, a reversible thermosensitive recording layer, a primer layer B, a light reflection layer,
A configuration in which an adhesive layer and the like are sequentially laminated by coating or the like is employed. As the reversible thermosensitive recording layer, a layer in which a relatively large amount of an organic low-molecular substance such as a fatty acid is dispersed in a synthetic resin such as a vinyl chloride-vinyl acetate copolymer is used.

To form such a reversible thermosensitive recording layer, the coating solution is prepared by dissolving the synthetic resin and the organic low-molecular substance such as fatty acid, which are incompatible with each other, in an organic solvent in a predetermined proportion. A reversible thermosensitive recording layer in which organic low-molecular-weight substances such as fatty acids are uniformly dispersed in a synthetic resin film. Is formed. At this time, some of the organic low-molecular substances such as fatty acids also appear on the surface of the film due to migration, but the fatty acids and the like exposed on the surface of the film also act as a slip agent, so another layer is further laminated thereon. Attempting to do so may be a factor in inhibiting its adhesion.

In particular, when the transfer method is adopted, the order of lamination of the layers in the production of the transfer sheet is the reverse of the order in which the layers are laminated directly on the base sheet by coating or the like. A light reflection layer is laminated on the recording layer. However, even if a metal deposition layer or the like is directly laminated on the reversible thermosensitive recording layer, good adhesiveness cannot be obtained for the above-mentioned reason. For this reason, a method is employed in which a primer layer B is laminated on the reversible thermosensitive recording layer, and a deposited metal film or the like is laminated thereon. By adopting this method, the effect of improving the adhesiveness can be obtained to some extent, but the lamination of the primer layer B is performed by applying a coating solution of a primer resin dissolved in a solvent onto the reversible thermosensitive recording layer by coating or the like, and drying. Therefore, the organic low-molecular-weight substances such as fatty acids exposed on the surface of the reversible thermosensitive recording layer are redissolved, and partly migrate to the surface of the primer layer B again. Therefore, providing the primer layer B by such a method can reduce the adverse effects of organic low-molecular substances such as fatty acids, but cannot completely eliminate them.

As a result of intensive studies to solve such a problem, the deposition of a metal thin film layer by direct vapor deposition or the like on a surface where an organic low-molecular substance such as a fatty acid migrates and is exposed or may be exposed. Stop, the metal thin film layer and the layer that protects it in advance on the substrate sheet surface, that is,
By laminating a primer layer B, a releasable resin layer, and the like by a coating method or a transfer method, and laminating a layer including a reversible thermosensitive recording layer thereon by a transfer method, an organic low molecular substance for a metal thin film layer is formed. The present invention has been found that it is possible to avoid the adhesion inhibiting effect of the present invention, and it is also possible to easily form a partial print recording portion easily.

That is, the invention according to the first aspect includes a repetitive print recording section in which at least a light reflection layer, a reversible thermosensitive recording layer, and a protective layer are sequentially laminated on at least a part of the base sheet. In the repetitive print recording medium, the layer including at least the reversible thermosensitive recording layer of the repetitive print recording portion is constituted by a transfer layer formed by transfer on a light reflection layer laminated on the base sheet, and the protective layer Is composed of an ionizing radiation-curable resin having an elongation of 5% or more.

The invention described in claim 2 is the first invention.
In the repetitive printing recording medium according to the invention, the light reflection layer is configured as a transfer layer by transfer on a base sheet.

According to the third aspect of the present invention, at least a part of the base sheet is provided with a repetitive print recording section in which at least a light reflection layer, a reversible thermosensitive recording layer, and a protective layer are sequentially laminated. In the method for producing a repetitive print recording medium, a layer including at least the reversible thermosensitive recording layer of the repetitive print recording section is laminated by a transfer method on a light reflection layer laminated on a base material sheet. It consists of a method for manufacturing a repetitive printing recording medium.

According to a fourth aspect of the present invention, in the method for manufacturing a repetitive print recording medium according to the third aspect, the light reflection layer is also laminated on the base sheet by a transfer method. This is a method for manufacturing a repeated printing recording medium.
In the present invention, the elongation percentage is determined according to JIS K-7127.
This is based on the tensile elongation at break (test speed F) of the tensile test method for plastic films and sheets.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention, such as the materials used for the repetitive printing recording medium of the present invention and the manufacturing method, will be described below. The repetitive print recording medium of the present invention is manufactured by a transfer method so that the repetitive print recording section can be provided in an arbitrary shape and size not only on the entire surface of the base sheet as described above, but also on some surfaces. In this case, in order to maintain good adhesive strength between the layers constituting the repetitive print recording section, roughly two types of manufacturing methods can be adopted.

In the first method, when a repetitive print recording section is provided on a substrate sheet, first, a light reflecting layer (usually a metal thin film layer formed by a vacuum deposition method or the like) on the substrate sheet directly or via a primer layer. Is provided thereon, and a primer layer for improving the protection of the light reflecting layer and further improving the adhesion to the layer including the reversible thermosensitive recording layer laminated thereon by the transfer method is further provided. Up to this stage, the primer layer can be freely provided partially or entirely using a normal printing or coating method. Regarding the formation of the metal thin film layer, either of the partial vapor deposition and the entire vapor deposition is possible.
Then, on the primer layer, a reversible thermosensitive recording layer or a layer containing a reversible thermosensitive recording layer and a protective layer, for example, an adhesive layer / reversible thermosensitive recording layer / primer layer A / protective layer. This is a method in which a transfer layer is transferred to a desired shape by using a transfer method, laminated, and a repetitive print recording section is provided.

In the second method, when a repetitive print recording section is provided on a substrate sheet, a layer containing a light reflection layer, for example, an adhesive layer / light reflection layer / primer layer B / (peelability) A transfer layer composed of a resin layer) and the like, transferred and patterned in a transfer method in a pattern or the like, and then laminated, and then a reversible thermosensitive recording layer or a layer containing a reversible thermosensitive recording layer and a protective layer, for example, an adhesive layer / reversible thermosensitive layer This is a method in which a transfer layer comprising a recording layer / primer layer A / protective layer and the like is transferred by a transfer method so as to overlap the layer including the light reflecting layer in the same shape, and laminated to form a repetitive print recording section.

Hereinafter, a specific method for producing the repetitive print recording medium of the present invention will be described in the second production method having a large number of layers to be laminated, that is, a layer including a light reflection layer, a reversible thermosensitive recording layer, Alternatively, a method of providing a repetitive print recording section by at least two-stage transfer of a layer including a reversible thermosensitive recording layer and a protective layer will be described as an example. (Substrate sheet) First, there is no particular limitation on the material of the substrate sheet for providing the repetitive print recording section by transfer. In addition to various plastic sheets, sheets of paper or metal, etc., alone or laminated Free to use in sheet form. Examples of the plastic sheet include polyester such as polyethylene terephthalate, polystyrene resin such as polystyrene and ABS resin, polyvinyl chloride, acrylic resin, and polycarbonate. Although the thickness of the base sheet varies depending on the material and the use and is not particularly limited, a thickness of about 80 μm to 1 mm is usually appropriate. When a repetitive print recording section is provided on a part of the surface of such a base sheet, a magnetic recording layer or an IC may be provided in a margin thereof, and a multifunctional combination of these may be provided. An information recording medium can also be manufactured.

[Transfer Sheet] The transfer sheet used for producing the repetitive print recording medium of the present invention includes a transfer sheet used for transferring a layer including a light reflecting layer, a reversible thermosensitive recording layer,
Alternatively, the transfer sheet is roughly classified into a transfer sheet used for transferring a layer including a reversible thermosensitive recording layer and a protective layer. In each of the transfer sheets, a mechanism for peeling a transfer layer provided on a support sheet is used. Can be adopted. That is, in the transfer sheet used for transfer of the layer including the light reflection layer, the releasable resin layer, the primer layer B,
A transfer sheet can be formed by sequentially laminating a light reflection layer (metal thin film layer) and an adhesive layer. In this case, when the adhesion of the light reflection layer to the peelable resin layer is good, the primer layer B can be omitted. In this configuration, the transfer is performed at the interface between the support sheet and the peelable resin layer, and the transfer layer is formed below the peelable resin layer. From the support sheet side, a release resin layer, a primer layer B,
A transfer sheet can be formed by sequentially laminating a light reflection layer (metal thin film layer) and an adhesive layer. In this configuration, the transfer layer is formed by peeling off at the interface between the release resin layer and the primer layer B, and the layer below the primer layer B becomes the transfer layer. As described above, depending on whether the releasable resin layer is first laminated on the support sheet or the releasable resin layer is laminated, the interface to be peeled is different and the configuration of the transfer layer is also different. Either of the above configurations may be employed, but the configuration can be appropriately determined in consideration of both the performance of the transfer layer after the transfer and the ease of adjustment of the releasability.

Next, in the case of the present invention, the material of the protective layer is limited in the transfer sheet used for the transfer of the reversible thermosensitive recording layer or the layer including the reversible thermosensitive recording layer and the protective layer.
The above-described method in which a peelable resin layer is laminated on the protective layer after the transfer is not preferable. Therefore, the configuration of the transfer sheet is
For example, it is preferable to adopt a configuration in which a release resin layer, a protective layer, a primer layer A, a reversible thermosensitive recording layer, and an adhesive layer are sequentially laminated from the support sheet side. In the case of this configuration, the interface between the release resin layer and the protective layer is a release surface, and the portion below the protective layer is a transfer layer. In addition, the reversible thermosensitive recording layer and the protective layer can be separately separated and laminated. In this case, the transfer layer including the reversible thermosensitive recording layer and the transfer layer including the protective layer are sequentially transferred. The transfer layer including the reversible thermosensitive recording layer alone may be transferred, and the protective layer may be stacked thereon by coating or printing.

Hereinafter, each layer used in the transfer sheet will be described. (Support sheet) As the support sheet serving as a base material of the transfer sheet, heat resistance and solvent resistance when each layer to be laminated thereon is sequentially formed by coating or the like, and the formed transfer layer is used as a card or the like When using a thermal transfer method when transferring to a base sheet, the heat resistance is required, and a plastic film with these properties
For example, a biaxially stretched polyethylene terephthalate film (hereinafter, referred to as a biaxially stretched PET film) or the like can be used. When a biaxially stretched PET film is used, its thickness is appropriately about 25 μm in consideration of workability, tensile strength, thermal efficiency at the time of thermal transfer, and the like.

(Releasable Resin Layer) The releasable resin layer can be used by first laminating the support sheet with a coating or the like when the light reflecting layer is laminated on the substrate sheet by the transfer method. The main function is to have an appropriate peeling property with respect to the support sheet, that is, winding up, rewinding, etc., to such an extent that it does not peel off in normal handling, and can be easily peeled off during transfer, It is necessary to adhere well to the primer layer B (the light reflecting layer (metal thin film layer) when the primer layer B is not used) laminated on the peelable resin layer. There is no particular limitation as long as the resin has such a function. For example, biaxially stretched PE
When a T film is used, an acrylic / cellulose-based resin or the like can be suitably used. The thickness of the releasable resin layer may be thin, and an appropriate thickness is 1 to 3 μm.

(Releaseable resin layer) When the above-mentioned releasable resin layer is not used for the support sheet, a release resin layer is laminated on the support sheet. As a function required for the release resin layer, the primer layer B and the protective layer that adhere well to the support sheet and are laminated on the release resin layer are, as described above, ordinary Adhere to the extent that it does not peel off during handling,
It is necessary that the film can be easily peeled off at the time of transfer, and it is preferable that the film has heat resistance and solvent resistance as its performance. There is no particular limitation as long as the resin has such functions and performances. For example, various thermosetting resins excellent in crosslinkability, such as melamine resins, can be suitably used. By using such a resin while controlling the degree of crosslinking, the peeling force at the time of transfer can be appropriately adjusted. The releasable resin layer can be formed by a coating method using a reverse roll coater or the like, and its thickness may be thin, and about 1 to 4 μm is sufficient.

(Primer layer B) In the transfer sheet used to transfer the layer including the light reflecting layer, before providing the light reflecting layer by metal deposition or the like on the release resin layer or the release resin layer, A primer layer (primer layer B for distinguishing from other primer layers) is provided. When the light reflection layer is provided as a metal thin film layer by a vacuum evaporation method, a sputtering method, or the like, the primer layer B serves as a primer layer for evaporation or sputtering, has a smooth surface, and has a good metal thin film layer. It is necessary to have heat resistance enough not to be softened or deformed by heat at the time of vapor deposition or the like. If the surface of the primer layer B is not smooth, the gloss of the metal thin film layer is not sufficiently obtained, and the heat resistance is low, and the metal thin film layer is softened by heat at the time of vapor deposition and deformed. May cause loss of gloss of the metal thin film layer,
It is not preferable because interference fringes are generated and the function of the light reflection layer is impaired. For such a primer layer B, a polyester resin, a urethane resin, a vinyl chloride-vinyl acetate copolymer resin, an acrylic resin, or the like can be used, and these resins are dissolved in an organic solvent to form a coating solution. age,
This can be provided by applying and drying using a known application means such as reverse roll coating, and if necessary, performing a curing treatment or the like. The thickness is suitably in the range of 1 to 5 μm.

(Light Reflecting Layer) The light reflecting layer provided on the primer layer B is not particularly limited as long as it has high light reflection efficiency. For example, a metal thin film layer of aluminum, tin, nickel or the like can be suitably used. These metal thin-film layers can be formed by a vacuum deposition method, a sputtering method, or the like, and the thickness thereof is not particularly limited, but is usually in the range of 300 to 1000 °.

(Adhesive Layer) Transfer is performed on the light reflecting layer, or on a reversible thermosensitive recording layer, or on a transfer sheet including a reversible thermosensitive recording layer and a protective layer, on a reversible thermosensitive recording layer. Provide the necessary adhesive layer for the purpose. The type of adhesive used for the adhesive layer can be properly selected depending on the transfer method to be used. That is, a heat-sensitive adhesive (such as a so-called heat sealant) is used when transferring to a substrate sheet of a material to be transferred by applying heat and pressure by a heat transfer method, and a pressure-sensitive adhesive is used when transferring by only pressure. An adhesive can be used. As the heat-sensitive adhesive, various thermoplastic resins having good adhesiveness to the light reflection layer or the reversible heat-sensitive recording layer and having good heat sealing properties (heat adhesion) to the base sheet can be used. For example, a suitable resin is selected from vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, polyester resin, polyurethane resin, polyamide resin, etc. Can be used alone or in a mixed system of two or more kinds, and if necessary, a hard resin or other additives can be added.

As the pressure-sensitive adhesive, various kinds of well-known pressure-sensitive adhesives and delayed-tack-type adhesives (adhesives that exhibit tackiness by heating and maintain the tackiness for a certain period of time and then adhere) are used. can do. As the pressure-sensitive adhesive, a pressure-sensitive adhesive having high adhesive strength and excellent in heat resistance, cold resistance and durability is preferable. In view of this, a pressure-sensitive adhesive of silicone resin or acrylic resin is suitable. When using an adhesive,
It is preferable that a release paper or the like be overlaid on the pressure-sensitive adhesive applied surface to protect the pressure-sensitive adhesive surface until use. The formation of the adhesive layer as described above is usually performed by applying and drying a solution adhesive with a roll coater or the like, but depending on the type of the adhesive, a method of applying by a melt extrusion coating method and cooling. Can also be formed. The thickness of the adhesive layer is preferably in the range of 1 to 5 μm.
It may be μm.

Next, in a transfer sheet used for transferring a layer containing a reversible thermosensitive recording layer and a protective layer, a release resin layer is provided on a support sheet, and then a transfer layer is formed thereon as a transfer layer. , Protective layer / primer layer A / reversible thermosensitive recording layer /
A configuration in which adhesive layers are sequentially laminated can be employed. Hereinafter, the protective layer, the primer layer A, and the reversible thermosensitive recording layer will be described in order.

(Protective Layer) The protective layer laminated on the release resin layer becomes the outermost layer of the repetitive print recording section after the transfer,
This layer is provided to protect the reversible thermosensitive recording layer and the like in the lower layer and increase the durability of the repetitively printed recording medium. Such a protective layer is formed by a primer layer A, a reversible thermosensitive recording layer, a heat applied at the time of forming the adhesive layer, and a heat applied at the time of transfer, which are further laminated on the transfer sheet at the production stage. It is necessary to have heat resistance against heat applied at the time of rewriting, transparency, abrasion resistance, chemical resistance, stain resistance, etc., and a physical load (pressure) applied to the reversible thermosensitive recording layer during repeated rewriting. ) Is required, and cushioning properties for preventing deterioration due to deformation or the like, that is, elasticity are also required.

As a resin having such performance,
An ionizing radiation-curable resin having an elongation of 5% or more is suitable, and specifically, a polyene / thiol-based ionizing radiation-curable resin or a urethane acrylate-based ionizing radiation having a bifunctional or lower flexibility. Curable resins and the like are particularly suitable. A polyene / thiol ionizing radiation-curable resin is a cured product obtained by a combination of a polyfunctional unsaturated compound (polyene) and a polyfunctional thiol, and the cured coating film has heat resistance and high elasticity (elongation). Rate of 5% or more) and also has excellent wear resistance, so that it can be suitably used. Examples of the urethane acrylate-based ionizing radiation-curable resin having bifunctional or lower flexibility include, for example, bifunctional or lower polyester urethane acrylate,
Bifunctional or lower polyether urethane acrylate can be used. In this case, a difunctional or less functional monomer can be added as a reactive diluent for adjusting the viscosity of the coating solution. When a urethane acrylate-based ionizing radiation-curable resin having a functionality of three or more is used, the crosslink density becomes high, the protective layer becomes hard, and the above-mentioned elasticity cannot be obtained.

In the above protective layer, if necessary,
Additives such as a surfactant, an antistatic agent, and an ultraviolet absorber can also be added. However, when the transfer method is adopted, the reversible thermosensitive recording layer is provided directly or via a primer layer on the protective layer of the transfer sheet. It is necessary to adjust the addition amount. And the thickness of the protective layer to be formed is
About 2 to 10 μm is appropriate. If the thickness is less than 2 μm, the scratch resistance is insufficient, the cushion effect is not obtained, and the reversible thermosensitive recording layer is deteriorated by repeated rewriting, which is not preferable. Further, a thickness exceeding 10 μm is not preferable because it lowers the printing sensitivity of the reversible thermosensitive recording layer.

When the resin for the protective layer as described above is applied by a conventionally known roll coating or printing method, various organic solvents may be added as needed for viscosity adjustment. In this case, after the application, first, hot air drying for removing the organic solvent may be performed, and then the ionizing radiation-curable resin may be cured. Further, regarding the curing method of these ionizing radiation-curable resins, UV (ultraviolet) curing, EB
Either method of (electron beam) curing can be used.

(Primer layer A) A reversible thermosensitive recording layer is provided on the protective layer. In the present invention, the protective layer has an elongation of 5%.
The above-mentioned ionizing radiation-curable resin is used, and since the cured film of this resin has a property that other resins are relatively hard to adhere to the surface thereof, even if the reversible thermosensitive recording layer is directly laminated by coating or the like. Adhesion is insufficient. Therefore,
On the surface of the protective layer, a method of performing a known easy adhesion treatment such as a corona discharge treatment, a method of providing a primer layer,
It is preferable to employ some means for improving the adhesiveness, such as a method of combining the two. Among these, the method of or is more effective, and at least the primer layer (primer layer A for distinguishing from other primer layers)
Is preferably provided.

As the primer layer A, a primer using a urethane resin, a polyester resin, a vinyl chloride-vinyl acetate copolymer resin, an acrylic resin or the like can be used. Primers with synthetic resin emulsions are particularly suitable.
In the case of a water-dispersed synthetic resin emulsion, the resin is in the form of fine particles, and the functional groups on the surface thereof can be more effectively used for adhesion, so that the effect of improving the adhesion is excellent. Such a primer layer A can be formed by coating using a roll coater or the like. In particular, in the case of an aqueous dispersion such as an emulsion, in order to increase the adhesive strength, heating during drying is sufficiently performed to ensure the film formation. It is necessary to do. The thickness of the primer layer A may be thin, 1-2 μm
Is appropriate.

(Reversible thermosensitive recording layer) Next, as the reversible thermosensitive recording layer to be laminated on the primer layer A, a layer formed by dispersing an organic low-molecular substance such as a fatty acid in a synthetic resin is usually used. Can be used. In this case, it is preferable that the synthetic resin be transparent, have good film-forming properties, and be capable of uniformly dispersing and holding a low-molecular organic substance. Examples of such synthetic resins include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer and partially saponified products thereof, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-
Vinyl chloride resins such as acrylate copolymers.
Vinylidene chloride resins such as vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylate copolymer, vinylidene chloride-acrylonitrile copolymer; In addition, acrylic resins such as various polyacrylic esters and polymethacrylic esters, and other various polyester resins can be used.

The organic low-molecular substances dispersed in the synthetic resin of the reversible thermosensitive recording layer include various fatty acids,
Its derivatives can be used. Among them, saturated linear fatty acids are preferable, and in particular, carbon number C: 10 to 30, melting point: 30 to
Those in the range of 160 ° C. are preferred. These organic low-molecular substances can be dispersed in the synthetic resin as one kind or a mixture of two or more kinds, and in particular, organic low-molecular substances having different melting points, for example, monocarboxylic acid and dicarboxylic acid of saturated linear fatty acid The use of a mixture of the above is preferred in that the temperature range for making the film transparent is broadened.

Examples of such substances include capric acid, lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachiic acid, heneicosanoic acid, and behenic acid. , Trichosanoic acid, lignoceric acid, pentacosanoic acid, and the like. Among the dicarboxylic acids, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid, dodecane diacid, tridecane diacid,
Tetradecane diacid, pentadecane diacid, hexadecane 2
Acid, heptadecane diacid, octadecane diacid, nonadecane diacid, eicosane diacid, heneicosane diacid, docosan diacid, and the like. Further, the mixing amount of the organic low-molecular substance with respect to the synthetic resin is about 1% to 60% by weight, and more preferably 15% to 50% by weight, as the content of the organic low-molecular substance with respect to the whole. When the content of the organic low-molecular substance is 1% by weight or less, the print density is low and the sharpness becomes insufficient. On the other hand, when the content is 60% by weight or more, it becomes difficult to form a uniform coating film, which is not preferable.

The reversible thermosensitive recording layer may be added with a small amount of a high-boiling solvent or a surfactant in order to improve the film-forming properties and processability. Specific examples of such additives include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, butylbenzyl phthalate, dioctyl phthalate, diisooctyl phthalate, dicapryl phthalate, dicapryl phthalate, and high-boiling solvents (plasticizers). Diisobutyl acid, dioctyl adipate, dibenzyl sebacate, dioctyl sebacate, triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, triacetin and the like.

Examples of the surfactant include higher fatty acid alkali salts, polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, fatty acid monoglyceride, polyhydric alcohol higher fatty acid ester, polyhydric alcohol higher alkyl ether, and higher fatty acid alkyl sulfone. Acid salts, higher fatty acid alkylaryl sulfonates, higher amine halogenates and the like.

The reversible thermosensitive recording layer composed of the above-mentioned materials is prepared by dissolving each material in an organic solvent at a predetermined mixing ratio to prepare a coating solution. By means such as roll coating or printing
It can be formed by coating and drying. The thickness of the reversible thermosensitive recording layer is suitably in the range of 2 to 20 μm.
The range is more preferably from 15 to 15 μm.

The reversible thermosensitive recording layer includes, in addition to the above-mentioned resin layer in which organic low-molecular substances such as fatty acids are dispersed in the synthetic resin, a layer in which liquid crystal is dispersed in the synthetic resin,
That is, a liquid crystal / polymer composite film (hereinafter, simply referred to as a PDLC film) in which a smectic liquid crystal is dispersed in a polymer matrix can also be used. In this case, PDLC
The principle of writing (recording) and erasing visible information on a film utilizes light transmission and light scattering in an alignment state and a random alignment state of liquid crystal molecules by heat and an electric field (heat-electric field mode). Therefore, writing of information to the PDLC film can be performed by one of heat and electric field, and erasing of information can be performed by the other. This writing and erasing can be repeatedly performed. still,
A dichroic dye may be mixed in the smectic liquid crystal for the purpose of improving the contrast ratio or coloring. Then, the recorded information is displayed as white turbid light due to light scattering (in the case of using a dichroic dye, colored light due to the dye), and when erasing is performed by transparency through light transmission, printing (writing) is performed. ) Is performed by a heating means, such as a thermal head, which can be heated in a spot manner, and erasing is performed, for example, by applying an electric field equal to or more than a threshold of liquid crystal alignment to the PDLC film while heating as necessary. it can.

Such a PDLC film is usually formed, for example, by 2
An electrode (aluminum vapor-deposited film is preferably used because it also has an electrode function and a reflector function) is provided on a base sheet such as an axially stretched PET film, and a PDLC film is formed thereon by a coating method or the like. On the membrane,
It is used in such a configuration that a transparent electrode is formed as necessary and a protective layer is further provided thereon. Therefore, when the PDLC film is used for the repetitive print recording medium of the present invention, for example, by using an aluminum vapor-deposited film as the light reflection layer of the layer including the light reflection layer that is stacked first on the base sheet, Can be used as an electrode and a light reflecting layer, so that a transfer layer to be transferred thereon is formed on a release resin layer laminated on a support sheet, a protective layer, a primer layer A, and if necessary, a transparent layer. The electrode layer, the PDLC film, and the adhesive layer can be used without any problem by being sequentially laminated.

Next, the constituent materials of the PDLC film and the method of forming the same will be described. First, the liquid crystal material to be used is a smectic liquid crystal, and any conventionally known smectic liquid crystal can be used. These smectic liquid crystals preferably have a wide temperature range exhibiting a nematic phase. For example, by using a smectic liquid crystal material having a temperature range exhibiting a nematic phase of 1 ° C. or more, a driving voltage for making a PDLC film transparent is used. Can be reduced. A dichroic dye can be added to the smectic liquid crystal for the purpose of improving the contrast ratio or coloring. The dichroic dye is not particularly limited, and any of an azo type, a perylene type, an anthraquinone type and the like can be used, and can be added at a ratio of 1 to 10 parts by weight per 100 parts by weight of the smectic liquid crystal.

As the material of the polymer matrix in which the liquid crystal is dispersed, any polymer can be used as long as it is not compatible with the liquid crystal and is excellent in transparency and film forming ability. Specifically, an appropriate polymer material, for example, a polyvinyl alcohol, a fumarate resin, an epoxy resin, a polycarbonate, a UV-curable resin of polythiol, or the like can be used in accordance with the method for forming the PDLC film.

The liquid crystal may be microencapsulated, and the microencapsulation method is not particularly limited, and a conventionally known method is used. For example, in an aqueous medium, a liquid crystal or a liquid crystal in which a radical-reactive monomer is dissolved is used as a radical-reactive surfactant, a water-soluble protective colloid, or a radical-reactive protective colloid, or two or more of these. Emulsifying and dispersing in a mixture, dissolving or dispersing a radical initiator in water or in a liquid crystal,
By raising the temperature to the decomposition temperature of the initiator, a capsule wall film surrounding the liquid crystal particles can be formed.

As the radical polymerizable monomer to be dissolved in the liquid crystal, it is possible to use one having compatibility with the liquid crystal, such as styrene, vinyl acetate and (meth) acrylate. And it is better to mix monomers having two or more functions. As a radical initiator, water-soluble,
Oil-soluble or redox-based initiators can be used. It is also possible to initiate polymerization using ionizing radiation such as gamma rays or electron beams. In the microencapsulated liquid crystal having the above-described configuration, the polymer material used for the wall material is preferably used in a range of 5 to 25 parts by weight per 100 parts by weight of the smectic liquid crystal as the core material. The thickness of the wall in the encapsulated state varies depending on the liquid crystal material, polymer material, encapsulation method, and the like used, but is generally about 10 to 100 nm.

As a method for dispersing the liquid crystal in the polymer matrix, any known methods such as a phase separation method and an emulsion method can be used. For example, in the emulsion method, if necessary, a liquid crystal is emulsified and dispersed in a medium mainly containing water containing a surfactant and a protective colloid, and polyvinyl alcohol, gelatin, an acrylic acid copolymer, and A water-soluble or water-dispersible polymer material such as a water-soluble alkyd resin is added, and the mixture is stirred and dispersed to form an aqueous dispersion (emulsion).

The liquid crystal dispersion (emulsion) thus prepared is applied to a predetermined coating surface so as to have a required thickness, and dried to uniformly disperse the liquid crystal in the formed film. A PDLC film can be formed.
The thickness of the PDLC film thus formed is 3 to 25.
μm is preferred. If the film thickness is too small, light scattering (turbidity) at the time of heating becomes insufficient, and if the film thickness is too large, a large driving voltage is required for the alignment of the liquid crystal, which is not preferable. In the liquid crystal dispersion, the mixing ratio (weight ratio) of the polymer matrix forming material / liquid crystal is preferably in the range of 80/20 to 20/80. If the amount of liquid crystal used is too small, the transparency at the time of voltage application is insufficient, and it is not preferable in that a large voltage is required to make the film transparent, whereas if the amount of liquid crystal used is too large, Insufficient light scattering (turbidity) during heating,
Further, the strength of the film is undesirably reduced.

When a transfer sheet prepared by appropriately combining the above-described layers is used, if the transfer layer is not sufficiently cut, a desired transfer sheet is applied to the transfer sheet from the transfer layer side. It is also possible to insert a half-cut line in the shape and remove in advance an unnecessary part of the transfer layer, so-called grooving, to provide the transfer layer in an independent shape.

[0050]

The present invention will be described in more detail with reference to the drawings, specific examples and comparative examples. However, the present invention is not limited to these drawings and examples.
Further, the same reference numerals are used for the same reference numerals in different drawings. FIGS. 1 and 2 are schematic cross-sectional views each showing a configuration of an example of a transfer sheet used when a layer including a light reflection layer of the repetitive print recording medium of the present invention is laminated on a base sheet by a transfer method. . The transfer sheet 20 shown in FIG. 1 has a releasable resin layer 2, a primer layer B 4, a light reflection layer 5, an adhesive layer 6 on one surface of the support sheet 1.
Are sequentially laminated. In this configuration,
The release surface at the time of transfer is the interface between the support sheet 1 and the releasable resin layer 2, and the transfer layer 11 a is composed of four layers from the releasable resin layer 2 to the adhesive layer 6. The transfer sheet 20 shown in FIG. 2 has a structure in which a release resin layer 3, a primer layer B4, a light reflection layer 5, and an adhesive layer 6 are sequentially laminated on one surface of the support sheet 1. In the case of this configuration, the release surface at the time of transfer is the interface between the release resin layer 3 and the primer layer B4, and the transfer layer 11b is composed of three layers from the primer layer B4 to the adhesive layer 6.

FIG. 3 is a schematic cross-sectional view showing the structure of one embodiment of a transfer sheet used for transferring a layer containing a reversible thermosensitive recording layer and a protective layer of the repetitive printing recording medium of the present invention.
The transfer sheet 20 shown in FIG. 3 includes a release resin layer 3, a protective layer 7, a primer layer A8 on one surface of the support sheet 1.
The reversible thermosensitive recording layer 9 and the adhesive layer 6 are sequentially laminated. In the case of this configuration, the release surface at the time of transfer is the interface between the release resin layer 3 and the protective layer 7, and the transfer layer 12 is composed of four layers from the protective layer 7 to the adhesive layer 6.

FIGS. 4 and 5 are schematic sectional views showing the structure of an embodiment of the repetitive printing recording medium of the present invention. The repetitive print recording medium 40 shown in FIG.
The transfer layer 11a including the light reflection layer 5 is transferred and laminated on one side and a part of the side, and further, the same shape is aligned on the transfer layer 11a to protect the reversible thermosensitive recording layer 9 and the transfer layer 11a. The transfer layer 12 including the layer 7 is transferred and laminated, and a repetitive print recording unit 30 is provided. The repetitive print recording unit 30 of this configuration firstly
Using the transfer sheet 20 having the structure shown in FIG.
11a is transferred to a part of the surface of the base sheet, and then the transfer layer 12 is transferred thereon by using the transfer sheet 20 having the configuration shown in FIG.

The repetitive print recording medium 40 shown in FIG. 5 has a layer including the light reflection layer 5 on one entire surface of the base sheet 10.
As an example, a layer in which an adhesive layer 6, a light reflection layer 5, and a primer layer B4 are sequentially laminated from the side of the base sheet 1 (see FIG.
11b), and a layer containing a reversible thermosensitive recording layer 9 and a protective layer 7, that is, a layer including a reversible thermosensitive recording layer 9 and a protective layer 7 as shown in FIG.
The transfer layer 12 is transferred and laminated, and a repetitive print recording unit 30 is provided. The repetitive print recording unit 30 of this configuration firstly
Using the transfer sheet 20 having the structure shown in FIG.
b is transferred onto one entire surface of the base material sheet 10 and laminated, and then the transfer layer 12 is transferred onto a partial surface of the base material sheet 10 using the transfer sheet 20 having the structure shown in FIG. It can be formed by a transfer method. However, in the case of this configuration, the first layer including the light reflection layer 5 does not necessarily have to be stacked by a transfer method, but may be stacked by means such as coating or printing. In such a case, first, a primer layer B is formed on one entire surface or a partial surface of the base sheet as a deposition primer.
And a light-reflecting layer 5 is laminated thereon by full-vapor deposition or partial vapor-deposition, and a protective primer layer (may be a primer layer B) is further laminated thereon. Can be formed in any shape.

Example 1 A first transfer layer including a light reflecting layer and a second transfer layer including a reversible thermosensitive recording layer and a protective layer were sequentially laminated on a part of the surface of the base sheet. Transfer in two steps to form a repetitive print recording section, and to produce the repetitive print recording medium of Example 1. The transfer sheet (1)
, (2) and transfer to a substrate sheet.

[Preparation of Transfer Sheet (1)] A 25 μm-thick biaxially stretched transparent PET film (Lumilar T-60 manufactured by Toray Industries, Inc.) was used as a support sheet. A peelable resin layer (thickness: 1 μm), a primer layer B (thickness: 0.5 μm), a light reflection layer (aluminum vapor-deposited film: thickness: 600 mm), and an adhesive layer (thickness: 2 μm) are sequentially laminated, and a transfer sheet (1 ) Was prepared. In this case, the release surface at the time of transfer is the interface between the support sheet and the release resin layer. The thickness of each of the above layers is the thickness when dried.

Composition of coating liquid for peelable resin layer Acrylic / cellulose resin 10 parts by weight Diluent solvent (methyl ethyl ketone / toluene weight ratio 1: 1) 30 parts by weight Composition of coating liquid for primer layer B (primer for vapor deposition) Polyester type Resin 10 parts by weight Diluent solvent (methyl ethyl ketone / toluene, weight ratio 1: 1) 50 parts by weight The above coating solution was sequentially applied to a support sheet by a reverse roll coater and dried to laminate a peelable resin layer and a primer layer B.

Light Reflecting Layer A light reflecting layer (aluminum-deposited film) was deposited on the primer layer B by vacuum evaporation of aluminum to a thickness of 600 °.

Composition of Coating Solution for Adhesive Layer Vinyl chloride-vinyl acetate copolymer / acrylic resin mixed resin 10 parts by weight Diluent solvent (methyl ethyl ketone / toluene, weight ratio 1: 1) 25 parts by weight The above coating solution was subjected to a reverse roll coater. The adhesive layer was laminated on the aluminum vapor-deposited film by coating and drying to obtain a transfer sheet (1).

[Preparation of Transfer Sheet (2)] A 25-μm-thick biaxially stretched transparent PET film (Lumilar T-60 manufactured by Toray Industries, Inc.) was used as a support sheet. Release resin layer (2μm thickness)
After that, a protective layer (thickness: 4 μm), a primer layer A (thickness: 1 μm), a reversible thermosensitive recording layer (thickness: 10 μm), and an adhesive layer (thickness: 2 μm) are successively formed thereon by the following method. The transfer sheet (2) was prepared by lamination. In this case, the release surface at the time of transfer is the interface between the release resin layer and the protective layer. Also,
The thickness of each of the above layers is the thickness when dried. Hereinafter, similarly, the thickness indication of each layer is the thickness at the time of drying.

Composition of Coating Solution for Protective Layer Ionizing Radiation Curable Resin (Elongation 5% or More) UV Curable Urethane / Acrylate Resin (Bifunctional) 50 parts by weight Diluent Solvent (isopropyl alcohol) 50 parts by weight After applying with a reverse roll coater and drying the diluting solvent, an ultraviolet irradiation device (output: 160 W / c)
m high-pressure mercury lamp (2 lamps) at an irradiation distance of 10 cm and a line speed of 10 m / min to cure the coating.

A water-dispersed polyester resin (solid content: 20% by weight) was used as a coating solution for the primer layer A, and was coated on the protective layer with a reverse roll coater, dried with hot air, and sufficiently heated. Was performed to form a film.

Composition of coating solution for reversible thermosensitive recording layer Vinyl chloride-vinyl acetate copolymer (manufactured by VYHH UCC) 20 parts by weight Organic low molecular weight substance Behenic acid 8 parts by weight Sebacic acid 2 parts by weight Diluent solvent (tetrahydrofuran / ethyl) Cellosolve weight ratio 1: 1) 100 parts by weight The above coating solution was applied on the primer layer A with a reverse roll coater and dried to form a reversible thermosensitive recording layer.

Composition of Coating Solution for Adhesive Layer Vinyl chloride-vinyl acetate copolymer-based resin 25 parts by weight Diluent solvent (methyl ethyl ketone / toluene, weight ratio 1: 1) 75 parts by weight Reversible thermosensitive recording of the above coating solution using a reverse roll coater The adhesive layer was laminated by coating and drying on the layer to obtain a transfer sheet (2).

(Preparation of Repeated Print Recording Medium by Transfer) Next, a 0.75 mm thick polyvinyl chloride sheet for a card was used as a base material sheet of a material to be transferred. Using the transfer sheet (1) prepared in the above, using a hot stamping device, the first transfer layer including the light reflection layer was formed at a temperature of 140 ° C. on a rectangular plate having a length of 12 mm and a width of 40 mm.
The transfer is performed by heating and pressing under a condition of 0.5 seconds, and then, using a transfer sheet (2), the reversible thermosensitive recording layer and the protective layer are aligned with the transfer surface using the same apparatus. The second transfer layer was transferred under heat and pressure at 140 ° C. for 1.0 second, and a repetitive print recording section was provided to produce a repetitive print recording medium of Example 1. Since the reversible thermosensitive recording layer after transfer is in a cloudy state, it is further heated at 100 ° C. by a hot stamping device.
For 1.0 second for clarification.

The repetitive printing recording medium manufactured as described above has a configuration in which the following is laminated in order from the base sheet side. Base sheet (PVC sheet, thickness 0.75 mm) / adhesive layer (thickness 2 μm) / light reflection layer (aluminum vapor-deposited film, thickness 600 mm) / primer layer B (thickness 0.5 μm) / peelable resin layer (Thickness 1 μm) / adhesive layer (thickness 2 μm) / reversible thermosensitive recording layer (thickness 10 μm) / primer layer A (thickness 1 μm) / protective layer (ionizing radiation-curable urethane acrylate resin bifunctional, thick 4 μm)

Comparative Example 1 A transfer sheet was prepared by laminating a light reflecting layer, a reversible thermosensitive recording layer and a protective layer so as to be included in the same transfer layer, and this was used as a base for one transfer. A repetitive print recording medium of Comparative Example 1 was prepared by preparing a transfer sheet and transferring it to a base sheet as described below.

(Preparation of Transfer Sheet) A 25-μm-thick biaxially-stretched transparent PET film (Lumilar T-60 manufactured by Toray Industries, Inc.) was used as a support sheet, and one surface thereof was releasable with a melamine resin. After providing a resin layer (thickness 2 μm), a protective layer (thickness 4 μm)
m), primer layer A (1 μm thickness), reversible thermosensitive recording layer (10 μm thickness), primer layer B (1 μm thickness),
A light reflection layer (aluminum vapor-deposited film having a thickness of 600 Å) and an adhesive layer (thickness: 2 μm) were laminated to prepare a transfer sheet for a repetitive print recording section. The release surface of the transfer sheet at the time of transfer is the interface between the release resin layer and the protective layer.

Composition of Coating Solution for Protective Layer Ionizing Radiation Curable Resin (Elongation 5% or More) UV Curable Urethane Acrylate Resin (Bifunctional) 50 parts by weight Diluent Solvent (isopropyl alcohol) 50 parts by weight After applying with a reverse roll coater and drying the diluting solvent, an ultraviolet irradiation device (output: 160 W / c)
m high-pressure mercury lamp (2 lamps) at an irradiation distance of 10 cm and a line speed of 10 m / min to cure the coating.

A water-dispersed polyester resin (solid content: 20% by weight) was used as a coating liquid for the primer layer A, and was coated on the protective layer with a reverse roll coater, dried with hot air, and sufficiently heated. Was performed to form a film.

Composition of coating liquid for reversible thermosensitive recording layer Vinyl chloride-vinyl acetate copolymer (manufactured by VYHH UCC) 20 parts by weight Organic low molecular weight substance Behenic acid 8 parts by weight Sebacic acid 2 parts by weight Diluent solvent (tetrahydrofuran / ethyl) Cellosolve weight ratio 1: 1) 100 parts by weight The above coating solution was applied on the primer layer A with a reverse roll coater and dried to form a reversible thermosensitive recording layer.

Composition of Coating Solution for Primer Layer B (Primer for Vapor Deposition) Polyester resin 10 parts by weight Diluent solvent (methyl ethyl ketone / toluene weight ratio 1: 1) 50 parts by weight Reversible thermosensitive recording of the above coating solution with a reverse roll coater The primer layer B was laminated on the layer by coating and drying.

Light Reflecting Layer A light reflecting layer (aluminum deposited film) was deposited on the primer layer B by vacuum evaporation of aluminum to a thickness of 600 °.

Composition of Coating Solution for Adhesive Layer Vinyl chloride-vinyl acetate copolymer / acrylic resin mixed resin 10 parts by weight Diluent solvent (methyl ethyl ketone / toluene 1: 1 by weight) 25 parts by weight The above coating solution was subjected to a reverse roll coater. The adhesive layer was laminated and dried on the aluminum vapor-deposited film to obtain a transfer sheet.

(Preparation of Repetitive Print Recording Medium by Transfer) Next, a 0.75 mm thick polyvinyl chloride sheet for a card was used as a base material sheet of a material to be transferred. Using a transfer sheet prepared as described above, a hot stamping device was used to apply heat and pressure under a condition of 140 ° C. and 1.0 second to a rectangular plate having a size of 12 mm × 40 mm and a repetitive print recording portion was transferred. Was prepared.

The repetitive printing recording medium produced as described above has a configuration in which the recording medium is laminated as follows from the base sheet side. Base sheet (PVC sheet, thickness 0.75 mm) / adhesive layer (thickness 2 μm) / light reflection layer (aluminum vapor-deposited film, thickness 600 mm) / primer layer B (thickness 1 μm) / reversible thermosensitive recording layer ( 10 μm thick) / Primer layer A (1 μm thick)
m) / Protective layer (ionizing radiation-curable urethane acrylate resin bifunctional, 4 μm thick)

Comparative Example 2 In the structure of the repetitive printing recording medium of Example 1, the composition of the coating solution for the protective layer used for preparing the transfer sheet (2) was changed to the following composition, that is, the elongation percentage was 5% or more. Replaced with a hard type ionizing radiation-curable resin without
And, except that the thickness was changed so that the thickness at the time of drying becomes 3 μm, all the processing was performed in the same manner as in Example 1,
A repeated printing recording medium of Comparative Example 2 was produced. Composition of coating liquid for protective layer Ionizing radiation curable resin (elongation less than 5%) UV curable dipentaerythritol hexaacrylate (DPHA) (6-functional hard type) 50 parts by weight Diluent solvent isopropyl alcohol 50 parts by weight The coating amount was applied so that the thickness at the time of drying was 3 μm, applied, dried, cured by UV irradiation, and a protective layer was laminated.

[Evaluation and Results] Using the repetitive print recording media of Example 1 and Comparative Examples 1 and 2 prepared as described above as samples, the background density, adhesiveness, and rewriting of each repetitive print recording portion were obtained by the following methods. The durability was evaluated, and the results are shown in Table 1.

(Measurement of Background Density) For each sample, the background density (OD) after transfer (clearing) was measured with a Macbeth reflection densitometer RD-918S (visual filter), and the numerical values are shown in Table 1. The standard of the background density is usually 1.
0 or more.

(Evaluation Method of Adhesive Property) Adhesive property of the repetitive print recording area was evaluated by a cross cut test, and the JIS
In accordance with K5400, 1 mm
11 slits each in the vertical and horizontal directions are cut at intervals to form a grid of 10 rows in the vertical and horizontal directions, and a cellophane adhesive tape (Cellotape LD-18, manufactured by Nichiban Co., Ltd.) is adhered to the surface.
Peeling was performed in an 80 ° direction, and the peeling state was examined. Judgment was made only based on the presence or absence of peeling.
(Good), and those that had peeled are indicated in Table 1 by symbols (poor).

(Evaluation Method of Rewriting Durability) Printing and erasing were repeatedly performed under the following conditions, and the color density [print density (OD)] after initial and predetermined rewriting was measured by the reflection densitometer. At the same time, visual evaluation was performed, and the results are shown in Table 1 by numerical values and symbols. Printing method: 8 dots / mm by thermal head printer
Using a line-type thermal head, an image was formed with an applied energy of 0.30 mJ / dot. Erasing method: 100 ° C. using a hot stamping device
The image was erased by heating under the condition of 1.0 second. Evaluation criteria ○ (good): Color density (OD) up to 200 rewrites
Of less than 0.2, and no scratch or peeling occurred on the protective layer. × (bad): Color density (OD) by 200 rewrites
Is 0.2 or more, or the protective layer is scratched or peeled off.

[0081]

[Table 1]

As is clear from the evaluation results shown in Table 1,
The repetitive printing recording medium of Example 1 was excellent in all of the background density, adhesiveness, and rewriting durability of the repetitive printing recording portion. On the other hand, in the repeated print recording medium of Comparative Example 1, partial peeling was observed in the adhesiveness of the repeated print recording portion, that is, in the cross-cut test.
It was good up to 0 times, but after 200 times, the print density tended to decrease, and at the same time, the protective layer was scratched and inferior to the repetitive print recording medium of Example 1. The repeated printing recording medium of Comparative Example 2 had good background density and adhesiveness, but the protective layer had no cushioning property, and the rewriting durability showed a tendency to decrease the printing density after 50 times since the protective layer had no cushioning property. After 100 times, the print density significantly decreased, resulting in poor contrast.

[0083]

As described in detail above, claim 1 is as follows.
The invention described in (1) is a repetitive print recording medium provided with a repetitive print recording unit in which at least a light reflection layer, a reversible thermosensitive recording layer, and a protective layer are sequentially laminated on at least a part of a base sheet. At least the layer including the reversible thermosensitive recording layer of the print recording portion is constituted by a transfer layer formed by transfer on the light reflection layer laminated on the base sheet, and the protective layer has an elongation of 5% or more. It is a repetitive printing recording medium characterized by being composed of ionizing radiation curable resin,
The invention according to claim 2 is the repetitive print recording medium according to claim 1, wherein the light reflection layer is configured as a transfer layer by transfer on a base sheet.

By adopting such a configuration, the following effects can be obtained. (1) In the formation of each layer of the repetitive print recording section, at least the layer including the reversible thermosensitive recording layer is formed as a transfer layer by transfer separated from the layer including the light reflection layer. Compared to the case where each layer is directly laminated by coating or printing, the base sheet is not affected repeatedly by heat or solvent for a long time, and is easily affected by these materials, such as a polyvinyl chloride sheet. Etc. can be freely selected and used.
The repetitive print recording section can be provided at an arbitrary position and in an arbitrary shape and size on the entire surface or a part of the base sheet.

(2) As described above, the layer including the light reflection layer is first laminated on the base sheet, and the layer including at least the reversible thermosensitive recording layer is laminated thereon as a transfer layer by transfer. A primer layer B, an adhesive layer and the like are interposed between the light reflection layer formed by metal deposition and the reversible thermosensitive recording layer, and the organic low-molecular substance contained in the reversible thermosensitive recording layer migrates to the surface. There is no need to directly laminate the light reflection layer on such a layer by metal evaporation, etc.
The effect of the organic low-molecular substance (adhesion inhibition action) can be avoided, and the adhesiveness between the light reflective layer and the layer laminated thereon, which is a conventional weak point, is improved, and the adhesiveness of the entire repetitive print recording section is improved. , The rewriting durability is improved.

(3) Further, the repetitive print recording section includes, as main constituent layers, a light reflecting layer, a reversible thermosensitive recording layer, and a protective layer, and the protective layer has an elongation of 5% or more. Because it is composed of a mold resin, it has excellent repetitive print recording characteristics such as print contrast, and at the same time, the protective layer has excellent resistance to scratches and chemicals, as well as excellent cushioning properties. Since the physical load (pressure) applied during repeated rewriting can be reduced, deterioration due to deformation of the reversible thermosensitive recording layer can be prevented, and a repetitive printing recording medium excellent in rewriting durability can be provided. .

The invention according to claim 3 or 4 relates to the method for manufacturing a repetitive print recording medium according to claim 1 or 2, respectively. By adopting the method, it is possible to easily provide a repetitive print recording medium having excellent overall performance such as the suitability for use, repetitive print recording characteristics, and durability as described above.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an example of a transfer sheet used for transferring a layer including a light reflection layer.

FIG. 2 is a schematic cross-sectional view showing the configuration of another embodiment of a transfer sheet used for transferring a layer including a light reflection layer.

FIG. 3 is a schematic cross-sectional view showing a configuration of an example of a transfer sheet used for transferring a layer including a reversible thermosensitive recording layer and a protective layer.

FIG. 4 is a schematic sectional view showing a configuration of an embodiment of a repetitive print recording medium of the present invention.

FIG. 5 is a schematic sectional view showing the configuration of another embodiment of the repetitive printing recording medium of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Support sheet 2 Releasable resin layer 3 Release resin layer 4 Primer layer B 5 Light reflection layer 6 Adhesive layer 7 Protective layer 8 Primer layer A 9 Reversible thermosensitive recording layer 10 Base sheet 11a, 11b Transfer layer (light (For reflective layer) 12 Transfer layer (for reversible thermosensitive recording layer, protective layer) 20 Transfer sheet 30 Repeat print recording section 40 Repeat print recording medium

Claims (4)

[Claims] 1. A repetitive printing recording medium provided with a repetitive printing recording section in which at least a light reflection layer, a reversible thermosensitive recording layer, and a protective layer are sequentially laminated on at least a part of a base sheet. At least the layer including the reversible thermosensitive recording layer of the recording section is constituted by a transfer layer formed by transfer on the light reflection layer laminated on the base sheet, and the protective layer has an elongation of 5% or more. A repetitive printing recording medium comprising a radiation curable resin. 2. The repetitive printing recording medium according to claim 1, wherein said light reflection layer is formed as a transfer layer by transfer on a base sheet. 3. A method for producing a repetitive print recording medium, comprising at least a part of a base sheet provided with a repetitive print recording section in which at least a light reflection layer, a reversible thermosensitive recording layer, and a protective layer are sequentially laminated. A method for producing a repetitive printing recording medium, comprising laminating a layer containing at least a reversible thermosensitive recording layer of the repetitive printing recording section on a light reflecting layer laminated on a base sheet by a transfer method. 4. The method according to claim 3, wherein the light reflection layer is also laminated on the base sheet by a transfer method.