JP2003127558A - Heat transfer sheet for protective layer and image printed article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer sheet for a protective layer in which releasing properties of the protective layer are low when it is not transferred and the releasing properties of the protective layer becomes good when it is transferred to make it possible to stably transfer the protective layer in matching an image to be protected and in addition, even when the protective layer is transferred under a condition of low temperature and low humidity, delivery properties of the image on which the protective layer is transferred is excellent. SOLUTION: In the heat transfer sheet for the protective layer in which a releasing layer and the protective layer are laminated in this order on at least a part of one surface of the base material sheet, the heat transfer sheet for the protective layer is characterized by the releasing layer comprising a heat-crosslinking epoxy-amino resin or alkyd-amino resin and the protective layer comprising an acrylic resin as a main ingredient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective layer thermal transfer sheet provided with a protective layer which can be peeled off.

[0002]

2. Description of the Related Art At present, a thermal transfer recording method is widely used as a simple printing method. In the thermal transfer recording method, various images can be easily formed, and therefore, printed matter that requires a relatively small number of prints, for example, the production of ID cards such as identification cards, sales photographs, personal computer printers, video printers, etc. Is used in.

When a full-color gradation image such as a facial photograph is preferred as the thermal transfer sheet used, color materials such as yellow, magenta, and cyan (for example, yellow, magenta, and cyan (on a continuous base material sheet) are used. Furthermore, a large number of black color material layers are repeatedly provided in a frame-sequential manner as needed.

Further, such a thermal transfer sheet is roughly classified into a so-called melt transfer type thermal transfer sheet in which the color material layer is melted and softened by heating and the color material layer itself is transferred and transferred to a transfer target, that is, an image receiving sheet. The heat transfer sheet is classified as a so-called sublimation type thermal transfer sheet in which the dye in the color material layer is sublimated by heat and the dye is transferred to the image receiving sheet.

When an identification card or the like is produced using the thermal transfer sheet as described above, the use of a thermal fusion type thermal transfer sheet makes it easy to form a monotonous image such as letters and numbers. The image (1) has a drawback that it is inferior in durability, especially abrasion resistance.

On the other hand, when a sublimation type thermal transfer sheet is used, a gradation image such as a facial photograph can be formed precisely, but the formed image is different from that formed by ordinary printing ink. However, since it is formed of only a dye without a vehicle, it has a drawback that it is inferior in durability such as weather resistance, abrasion resistance and chemical resistance.

As a measure against the above, a protective layer heat transfer sheet having a transferable protective layer is superposed on an image obtained by thermal transfer of a heat fusible ink layer or a sublimable dye,
There is known a method of forming a protective layer on an image by transferring the transferable protective layer using a thermal head or a heating roll.

By providing the protective layer in this way,
The abrasion resistance, chemical resistance, solvent resistance, etc. of the image can be improved to some extent, and the light resistance can be improved by adding an ultraviolet absorber or the like to the protective layer.

[0009]

The protective layer thermal transfer sheet in the above prior art has a release layer made of various materials provided between the transferable protective layer and the base sheet. The release layer of the thermal transfer sheet has almost no difference in releasability from the protective layer when heat is not applied (before transfer) and when the protective layer is transferred. However, there is a problem that the transfer stability of the protective layer is inferior because the image to be protected does not match the protective layer.

Further, when the protective layer is transferred by using the conventional protective layer thermal transfer sheet, there is a problem that static electricity is generated at the time of transfer and the printed matter is charged and the dischargeability of the printed matter is deteriorated. Under low-humidity conditions, the problem of paper discharge due to this charging is increasing.

Therefore, an object of the present invention is that the peelability of the protective layer is low at the time of non-transfer and the peelability of the protective layer at the time of transfer is good, so that the protective layer can be stably transferred in conformity with the image to be protected. Another object of the present invention is to provide a protective layer thermal transfer sheet which is capable of transferring a protective layer under low-temperature and low-humidity conditions and which is excellent in discharging the image on which the protective layer is transferred.

[0012]

The above object can be achieved by the present invention described below. That is, the present invention is a protective layer thermal transfer sheet comprising a release layer and a protective layer laminated in this order on at least a part of one surface of the base sheet,
The release layer is a thermally crosslinkable epoxy-amino resin or alkyd-amino resin, and the protective layer,
Provided is a thermal transfer sheet for protective layer, which comprises an acrylic resin as a main component.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. FIG. 1 is a schematic enlarged cross-sectional view showing a basic form of a protective layer thermal transfer sheet 10 of the present invention, in which a transferable protective layer 3 is provided on one surface of a base material sheet 1 via a release layer 2. The heat resistant slipping layer 4 is provided on the other surface of the base material sheet 1. In a preferred embodiment, the heat sensitive adhesive layer 5 is provided on the surface of the protective layer.

FIG. 2 shows the thermal transfer sheet 10 for the protective layer of the present invention.
FIG. 6 is a schematic cross-sectional view showing another embodiment of the present invention, in which, in addition to the protective layer region composed of the release layer 2 and the transferable protective layer 3 similar to the above, on one surface of the base material sheet 1, Sublimable dye layer Y, M, C, Bk and heat-meltable ink layer 6 in the order of the protective layer and the surface layer.
And are respectively provided in the frame order. The heat resistant slipping layer 4 and the heat sensitive adhesive layer 5 are the same as in the case of FIG. By using the protective layer thermal transfer sheet of this embodiment, a desired image is formed on the thermal transfer image-receiving sheet and the protective layer is transferred to a desired image area by one type of protective layer thermal transfer sheet and one thermal printer. be able to.

FIG. 3 is a cross-sectional view of an image printed with the protective layer transferred to the image surface by the protective layer thermal transfer sheet of the present invention. In FIG. 3, the protective layer 3 is transferred via the adhesive layer 5 only to the surface of the dye image 9 formed on the base sheet 7 having the dye receiving layer 8 provided on the base 7 of the image receiving sheet. However, the protective layer 3 may be transferred to the whole including other images (for example, images such as characters formed by transferring the heat-meltable ink layer). The image to be protected is not limited to a dye image by a sublimation transfer method, and is not particularly limited to an inkjet image or an electrophotographic image having low surface durability.

Each layer constituting the protective layer thermal transfer sheet of the present invention will be described below. (Base Material Sheet) As the base material sheet used in the protective layer thermal transfer sheet of the present invention, the same base material sheet as that used in the conventional thermal transfer sheet can be used as it is, and the surface of the sheet can be used. Those that have been subjected to an easy-adhesion treatment, and others can be used, and there is no particular limitation.

Specific examples of preferable substrate sheets include, for example, polyester including polyethylene terephthalate, polycarbonate, polyamide, polyimide,
Plastic films such as cellulose acetate, polyvinylidene chloride, polyvinyl chloride, polystyrene, fluororesins, polypropylene, polyethylene and ionomers,
Also, there are papers such as glassine paper, condenser paper, and paraffin paper, cellophane, and the like, and a composite film in which two or more kinds of these are laminated can also be used. The thickness of these base material sheets is appropriately changed depending on the material so that the strength and heat resistance thereof are appropriate, but usually 2.5 to
About 100 μm is preferable.

(Release Layer) A release layer is provided on the substrate sheet to make the transferability of the transferable protective layer formed thereon appropriate. The first feature of the present invention is that the release layer is formed of a specific resin. The resin forming the release layer is a heat-crosslinkable epoxy-amino resin and / or a heat-crosslinkable alkyd-amino resin. Thermally crosslinkable epoxy-amino resins are known per se, for example TCM-02.
It can be used by obtaining it from the market under the product name such as medium (manufactured by Dainippon Ink and Chemicals). Alkyd-amino resins themselves are also known and can be used by being obtained from the market under the trade name of TD-01 transparent medium concrete, TCM-150 (all manufactured by Dainippon Ink and Chemicals) and the like. These heat-crosslinkable resins can be used alone or as a mixture.

In order to form a release layer from the above heat-crosslinkable resin, the above-mentioned resin together with a crosslinking agent or a catalyst in a general-purpose solvent such as methyl ethyl ketone, toluene or isopropyl alcohol, for example, the solid content is about 5 to 5. A coating solution is prepared by dissolving it to 50% by weight, and the coating solution is applied to a region of the substrate sheet where the transferable protective layer is to be formed by a conventionally known method such as gravure coating or gravure reverse coating. (Reference) Formed by coating and drying so as to have a thickness of about 0.5 to 5 μm.

The release layer may be appropriately selected from those which migrate to the transferred body during thermal transfer, those which remain on the substrate sheet side, and those which undergo cohesive failure, but the release layer is non-transferred. The surface glossiness is such that the release layer remains on the substrate sheet side due to thermal transfer and the interface between the release layer and the transferable protective layer is the surface of the protective layer after thermal transfer. , And the transfer stability of the protective layer is excellent. When a matte protective layer is desired after transfer, various particles are included in the release layer or the surface of the release layer on the protective layer side is matted to give a surface matte state. You can also

(Transferable Protective Layer) The second feature of the present invention is
That is, a transferable protective layer containing an acrylic resin as a main component is formed on the release layer surface. As the acrylic resin, various acrylic resins can be used. For example, DIALAL BR
It can be obtained from the market under the product name such as -83 (manufactured by Mitsubishi Rayon) and used.

In order to form the transferable protective layer from the acrylic resin as described above, the acrylic resin as described above is added to a general-purpose solvent such as methyl ethyl ketone, toluene or isopropyl alcohol to obtain a solid content of about 5 to 50% by weight. So as to prepare a coating liquid, and the coating liquid is applied to the surface of the release layer by a conventionally known method such as gravure coating or gravure reverse coating so that the thickness (drying standard) is about 0.5 to 5 μm. It is formed by coating and drying.

(Heat-sensitive adhesive layer) In the present invention, a heat-sensitive adhesive layer is formed on the surface of the transferable protective layer to improve the transfer of the transferable protective layer and the adhesion of the transferred protective layer to the image surface. It is preferable. For this heat-sensitive adhesive layer, any conventionally known heat-sensitive adhesive can be used, but it has a glass transition temperature of 5
It is more preferably formed from a thermoplastic resin having a temperature of 0 to 80 ° C., for example, an ultraviolet absorbing resin, an acrylic resin, a vinyl chloride-vinyl acetate copolymer resin, an epoxy resin, a polyester resin, a polycarbonate resin, a butyral resin, a polyamide resin. It is preferable to select a resin having an appropriate glass transition temperature from resins having good adhesiveness at the time of heat treatment such as vinyl chloride resin.

(Heat-Resistant Sliding Layer) The protective layer thermal transfer sheet of the present invention has a back surface of the substrate sheet, that is, a surface opposite to the surface on which the transferable protective layer is provided, such as sticking and wrinkles due to heat of the thermal head. A heat resistant slipping layer is provided to prevent adverse effects. The resin for forming the heat resistant slipping layer may be any conventionally known resin, for example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene. Resin, styrene-butadiene copolymer, acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetopropionate resin, cellulose acetate Butyrate resin, cellulose acetate hydrodiene phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polycarbonate resin, chlorination Such as Li olefin resins.

Further, in order to improve the heat resistance of the heat resistant slipping layer, the coating film strength and the adhesion to the substrate sheet, a reaction cured product of a thermoplastic resin having a reactive group in the resin and polyisocyanate, A reaction product with a monomer or an oligomer having an unsaturated bond can be used, and the curing method is not particularly limited, such as heating or irradiation with ionizing radiation.

Addition to the heat resistant slipping layer made of these resins,
Alternatively, as the slipperiness-imparting agent to be overcoated, phosphoric acid ester, silicone oil, graphite powder, silicone-based graft polymer, fluorine-based graft polymer,
Examples thereof include silicone polymers such as acrylic silicone graft polymers, acrylic siloxanes, and aryl siloxanes. Preferred are polyols, for example, a layer composed of a polyalcohol polymer compound, a polyisocyanate compound, and a phosphoric acid ester compound, and a filler. Is more preferably added.

The heat resistant slipping layer is prepared by dissolving or dispersing the resin, the slipperiness imparting agent, and the filler described above in a suitable solvent to prepare a heat resistant slipping layer-forming ink. It can be formed on the back surface of the above-mentioned substrate sheet by applying it by a forming means such as a gravure printing method, a screen printing method, a reverse coating method using a gravure plate, and drying. The thickness of the heat resistant slipping layer is about 0.1 to 2 μm in terms of solid content.

In the protective layer thermal transfer sheet of the present invention, the transferable protective layer described above may be provided alone on the substrate sheet, or as shown in FIG. 2, Y (yellow), M (magenta). , C (cyan), Bk (black), and the dye layer and the heat-meltable ink layer of each color may be provided in a frame order. The dye layer is formed from a suitable sublimable dye from a suitable binder resin by a known method, and the heat-meltable ink layer is formed from a suitable pigment and a heat-meltable substance such as a wax by a known method. .

There is no particular limitation on the image-receiving sheet which is a transfer-receiving body on which the protective layer is transferred and the image is formed by using the protective layer thermal transfer sheet as described above. For example, any sheet such as plain paper, high-quality paper, tracing paper, or plastic film may be used as the base material,
Any shape such as card, postcard, passport, letter paper, report paper, notebook, catalog, etc.,
The thing which provided the receiving layer which has the acceptability of a dye on the base material can be applied. The method of providing the receiving layer may be a coating method or thermal transfer using a thermal head or a heat roll. If the substrate itself has a dye receptive property, it is not necessary to provide a receptive layer.

The protective layer thermal transfer sheet of the present invention can be used to prepare cards such as ID cards, identification cards, and licenses. These cards include text information in addition to image information such as photographs. In this case, for example, the character information is formed by the melt transfer method,
An image such as a photograph can be formed by a sublimation transfer method. Further, the card can be provided with embossing, sign, IC memory, magnetic layer, hologram, and other printing, and after transfer of the protective layer, embossing, sign, magnetic layer and the like can be provided.

In the transfer, the thermal transfer printer may set transfer conditions such as sublimation transfer, melt transfer, and protective layer transfer separately, or the common printer may appropriately adjust the printing energy. You may go.
The protective layer thermal transfer sheet of the present invention is not limited to a thermal transfer printer as a heating means, and may be a thermal plate, a hot stamper, a thermal roll, a line heater, an iron or the like. Further, the protective layer may be transferred onto the entire surface of the formed image or may be transferred onto only a specific portion.

[0032]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts or% are based on weight unless otherwise specified. <Example 1> Polyethylene terephthalate film (PET, thickness 6.0 μm) having a heat resistant slipping layer formed on the back surface.
m, manufactured by Toray) The following release layer coating solution is applied to the surface by gravure printing at a predetermined dry coating amount, dried to form a release layer, and then the following protective layer coating is applied. The coating solution and the coating solution for the adhesive layer were sequentially applied in the same manner at a predetermined dry coating amount and dried to form a transferable protective layer and an adhesive layer to obtain a protective layer thermal transfer sheet of the present invention. .

[0033]

[0034]

[0035]

<Example 2> The following release layer coating solution was applied to the surface of the same substrate film as in Example 1 by gravure printing in a predetermined dry coating amount and dried to form a release layer. Further, a transferable protective layer and an adhesive layer were formed thereon in the same manner as in Example 1 to obtain a protective layer thermal transfer sheet of the present invention. (The protective layer and the adhesive layer are the same as in Example 1).

[0037]

<Example 3> The following release layer coating solution was applied to the surface of the same base film as in Example 1 by gravure printing in a predetermined dry coating amount and dried to form a release layer. Further, a transferable protective layer and an adhesive layer were formed thereon in the same manner as in Example 1 to obtain a protective layer thermal transfer sheet of the present invention. (The protective layer and the adhesive layer are the same as in Example 1).

[0039]

Example 4 The following release layer coating solution was applied to the surface of the same substrate film as in Example 1 by gravure printing at a predetermined dry coating amount and dried to form a release layer. Further, a transferable protective layer and an adhesive layer were formed thereon in the same manner as in Example 1 to obtain a protective layer thermal transfer sheet of the present invention. (The protective layer and the adhesive layer are the same as in Example 1).

[0041]

<Embodiment 5> On the surface of the same substrate film as in Embodiment 1, the following release layer coating solution was applied by gravure printing in a predetermined dry coating amount and dried to form a release layer. Further, a transferable protective layer and an adhesive layer were formed thereon in the same manner as in Example 1 to obtain a protective layer thermal transfer sheet of the present invention. (The protective layer and the adhesive layer are the same as in Example 1).

[0043]

Comparative Example 1 The following release layer coating solution was applied to the surface of the same base film as in Example 1 by gravure printing in a predetermined dry coating amount and dried to form a release layer. Further, the following protective layer coating liquid and adhesive layer coating liquid were similarly applied in the same manner at a predetermined dry coating amount and dried to form a transferable protective layer and an adhesive layer. A protective layer thermal transfer sheet of Comparative Example was obtained.

[0045]

[0046]

[0047]

Comparative Example 2 The following release layer coating solution was applied to the surface of the same base film as in Comparative Example 1 by gravure printing at a predetermined dry coating amount and dried to form a release layer. Then, a transferable protective layer and an adhesive layer were further formed thereon in the same manner as in Comparative Example 1 to obtain a protective layer thermal transfer sheet of Comparative Example. (The protective layer and the adhesive layer are the same as in Comparative Example 1).

[0049]

Comparative Example 3 The same release film coating solution as described below was applied to the surface of the same base film as in Comparative Example 1 by gravure printing at a predetermined dry coating amount, and dried to form a release layer. Then, a transferable protective layer and an adhesive layer were further formed thereon in the same manner as in Comparative Example 1 to obtain a protective layer thermal transfer sheet of Comparative Example. (The protective layer and the adhesive layer are the same as in Comparative Example 1).

[0051]

<Comparative Example 4> The following release layer coating solution was applied to the surface of the same base film as in Comparative Example 1 by gravure printing at a predetermined dry coating amount and dried to form a release layer. Then, a transferable protective layer and an adhesive layer were further formed thereon in the same manner as in Comparative Example 1 to obtain a protective layer thermal transfer sheet of Comparative Example. (The protective layer and the adhesive layer are the same as in Comparative Example 1).

[0053]

Comparative Example 5 The following release layer coating solution was applied to the surface of the same base film as in Comparative Example 1 by gravure printing at a predetermined dry coating amount and dried to form a release layer. Then, a transferable protective layer and an adhesive layer were further formed thereon in the same manner as in Comparative Example 1 to obtain a protective layer thermal transfer sheet of Comparative Example. (The protective layer and the adhesive layer are the same as in Comparative Example 1).

[0055]

Comparative Example 6 (No Release Layer) A transferable protective layer and an adhesive layer were formed on the surface of the same base film as in Comparative Example 1 in the same manner as in Comparative Example 1 to perform thermal transfer of the protective layer in Comparative Example. Got the sheet. (However, the release layer is not formed).

[0057]

[0058]

Comparative Example 7 The following release layer coating solution was applied to the surface of the same base film as in Comparative Example 1 by gravure printing at a predetermined dry coating amount and dried to form a release layer. Further, the following protective layer coating liquid and adhesive layer coating liquid were similarly applied in the same manner at a predetermined dry coating amount and dried to form a transferable protective layer and an adhesive layer. A protective layer thermal transfer sheet of Comparative Example was obtained.

[0060]

[0061]

[0062]

The constituent materials of the transferable protective layer in the above Examples and Comparative Examples are summarized in Table 1 below.

The following tests were conducted on the protective layer thermal transfer sheets of the above Examples and Comparative Examples, and the results are shown in Table 2.

[Peeling force] (1) Peeling force protective layer before application of heat A polyester tape (product name: Nitto tape 31C) manufactured by Nitto Denko Corporation was attached to the transfer layer side of the thermal transfer sheet, and the peeling force is specified in JIS P 8139. Using a T-shaped peeling jig, the measurement was performed with Haydon 14DR manufactured by Shinto Chemical Co., Ltd. under the following conditions.

(2) Peeling force after application of heat Heat energy is added using a thermal head of a printer which operates according to an electric signal obtained by color-separating a face photograph,
A full-color image was formed (the sublimation heat transfer sheet and the image receiving sheet used were those equipped in the above printer. Printing conditions: 20 msec / line, 14.5
V).

The image transfer side of the protective layer thermal transfer sheet was superposed on the image side of the above-mentioned printed matter so as to face it, and solid printing of 85 mm was performed by the above printer (temperature 0 ° C.). Thereafter, the thermal transfer sheet, the protective layer, the thermal transfer sheet and the printed matter were peeled off by T-shaped peeling in the same manner as described above, and the peeling force at that time was measured in the same manner as described above.

[Peeling Charge] After transferring the protective layer with the above printer, the charge on the surface of the printed matter was measured. The measuring instrument is a high precision electrostatic sensor SK-030 / 20 manufactured by Keyence Corporation.
0 was used, and the measurement site was set at a position 10 mm away from the surface of the print product for measurement.

[Paper discharge property of printed matter] The discharged state at the time of printing with the above printer was visually observed. The evaluation criteria are as follows. ◯: Good paper discharge property. X: Poor paper discharge property. Overlap occurs with the previous print.

[0070]

[0071]

As shown in Tables 1 and 2 above, by using an alkyd-amino resin and / or an epoxy-amino resin for the release layer in the protective layer thermal transfer sheet and using an acrylic resin for the protective layer, Good release properties can be imparted to the protective layer thermal transfer sheet. That is,
The peeling force (1) before applying heat and the peeling force (2) after applying heat have a desirable relationship (1)> (2), the protective layer does not detach when no heat is applied, and is stable when heat is applied. The protective layer can be peeled off. Further, by combining the release layer with a protective layer made of an acrylic resin, the amount of peeling charge at the time of transfer is reduced, and the problem of paper discharge property due to charging of the image receiving sheet is solved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a protective layer thermal transfer sheet of the present invention.

FIG. 2 is a schematic cross-sectional view of another example of the protective layer thermal transfer sheet of the present invention.

FIG. 3 is a cross-sectional view of the print product of the present invention.

[Explanation of symbols]

1: Base material sheet 2: Release layer 3: Transferable protective layer 4: Heat resistant slipping layer 5: Heat-sensitive adhesive layer 6: Heat-meltable ink layer 7: Base material 8: Dye receiving layer 9: Dye image 10: Protective layer thermal transfer sheet

Claims (3)

[Claims] 1. A protective layer thermal transfer sheet comprising a release layer and a protective layer laminated in this order on at least a portion of one surface of a base sheet, wherein the release layer is a thermally crosslinkable epoxy-amino acid. A protective layer thermal transfer sheet comprising a resin or an alkyd-amino resin, wherein the protective layer comprises an acrylic resin as a main component. 2. The protection according to claim 1, further comprising a sublimable dye layer and / or a heat-fusible ink layer formed on the same surface of the base material sheet on which the transferable protective layer is formed, in a surface-sequential manner. Layer heat transfer sheet. 3. A printed matter having a protective layer transferred from the protective layer thermal transfer sheet according to claim 1 on at least a part of the surface of the image.