JP2009056788A - Thermal-transfer sheet and its attaching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal-transfer sheet which has sufficient outdoor service durability(scratch-proof, mar-proof) without overcoat painting, surface gloss to give posh, is excellently decorative, attachable on a large area of three-dimensional curved surface, requires lower temperature for adhesion curing of the thermal-transfer sheet and usable for an adherend of low heat resistance. <P>SOLUTION: In the thermal-transfer sheet having a stripping pasteboard 1, a thermal adhesive layer 3, a coloring ink layer 4, a transparent clear layer 5, and a protective film layer 6 as needed; the thermal adhesive layer comprises a thermal adhesive containing a block isocyanate whose reaction initiates at 60°C or higher and 80°C or lower as a hardener and the transparent clear layer 5 comprises an ultraviolet curing transparent clear ink cured by ultraviolet irradiation to a surface hardness of the pencil hardness of H or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention can be applied to exterior parts of adherends used outdoors such as automobiles, motorcycles, boats, fishing gear, golf clubs, rackets, toys, helmets, vending machines, etc. In particular, a heat transfer sheet suitable for use on an adherend that is not overcoated or an adherend that is difficult to be baked at high temperatures. And an attaching method thereof.

  Conventionally, a heat transfer sheet has been widely known, a heat-sensitive adhesive ink provided on a transfer mount, a color ink layer provided on a transfer mount via a heat-sensitive adhesive layer, on these ink layers. Further, a transparent clear layer and, if necessary, a protective layer, a heat-sensitive ink provided on a transfer mount via a transparent clear layer, or a colored ink layer, a heat-sensitive adhesive layer on the transparent clear layer Various forms are known, such as those provided.

  Heat transfer sheets can easily apply complex patterns that cannot be applied to the adherend to the adherend. (B) Even if the adherend is a cubic curved surface, it easily follows the curved surface of the adherend. Yes, (c) It can be used for large areas where labels cannot be used, (d) Because it is a thin film, it can be decorated with high-quality decoration that does not make the sticking step feel, (e) Outdoor use It has a feature that it is excellent in durability. Because of these characteristics, the heat transfer sheet can be used to paint exterior parts of adherends used outdoors such as automobiles, motorcycles, boats, fishing gear, golf clubs, rackets, toys, helmets, and vending machines. It is preferably used for applying. For example, when considering the decoration of a motorcycle tank, the motorcycle tank is preferred to have a curved surface, a large decorative area, and a variety of decorative patterns, and durability (weather resistance, scratch resistance). In addition, since it is necessary to provide a high-quality decoration, it is impossible to cope with labeling or painting, and heat-sensitive transfer sheets are often used.

  Conventionally, in order to give a high-class feeling, “overcoat coating” in which a transparent clear is applied after applying a heat transfer sheet to an adherend is generally performed. The overcoat paint gives a glossy appearance and gives a more luxurious feel.In addition to this, the overcoat paint is used for the adherend that is usually used to stabilize the heat transfer sheet sticking workability and adhesion. There is also an effect of concealing scratches caused by surface polishing (sanding). However, a heat transfer sheet that can be used without overcoating is desired in the following cases.

1) We want to decorate plastic adherends that may be deformed at high temperatures 2) Overcoat coating or adherends that are difficult to be baked at high temperatures are used for reasons such as size and heat resistance 3) Lower costs 4) To reduce the defective rate (especially when it is required to reduce the defective rate in the overcoat painting process)
5) I want to suppress or reduce VOC emissions

  The inventors previously formed a transfer ink layer and a protective film layer by screen printing, and the vehicle in the transfer ink layer contains at least one of a high molecular epoxy resin, a low molecular epoxy resin, and a tackifying resin. The heating transfer sheet which consists of what was made and has a base material sheet, a transfer ink layer, and a protective film layer in this order was proposed (refer patent document 1). This transfer sheet has no deterioration due to aging and is excellent in weather resistance, and particularly excellent in adhesion to curved surfaces. However, if the overcoat is not applied, the pencil hardness is HB or less, so scratch resistance and scratch resistance. Is low and the appearance is matte. For this reason, overcoat coating has become indispensable for applications that require durability and luxury.

  There have been proposed several heat transfer sheets or heat transfer marks that can be used without being overcoated (see, for example, Patent Documents 2 to 4). Patent Document 2 describes a heat transfer mark in which a heat-sensitive adhesive layer, a colored ink layer, a transparent resin layer, and a protective film layer are sequentially laminated on a base sheet by screen printing. Is only described that the scratch resistance and scratch resistance can be improved by forming the transparent resin layer 5 by performing overprinting (printing a plurality of times). There is no more specific description to satisfy the scratch resistance. The transfer mark has a pencil hardness of HB or less and is easily scratched, and the required quality for outdoor durability cannot be satisfied without overcoat coating.

  Furthermore, in both of Patent Documents 1 and 2 above, in order to obtain high adhesiveness without performing overcoat coating, heating at a high temperature of 100 ° C. or higher is required to start the reaction of the curing agent of the heat-sensitive adhesive. It is. Even when overcoating is applied, the surface of the adherend is wetted with water so that the heat transfer sheet is slippery to improve the workability at the time of attachment, prevent air entrainment, and increase the anchoring performance. In order to obtain stable and high adhesiveness, it is common to sand the surface of the adherend with sandpaper or the like.

  In Patent Document 3, a thermosetting resin layer such as an epoxy-based or melamine-based resin that can be cured at a low temperature (60 to 150 ° C.) is provided between the thermosetting ink layer and the cover coat layer of the transfer mark. Although described, Patent Document 3 has no further description, and lacks in concreteness, and does not clarify the means for solving the scratch resistance and scratch resistance. Further, as pointed out in Patent Document 1, this transfer mark has a defect that it deteriorates with time and therefore lacks durability for long-term outdoor use.

  Patent Document 4 proposes a room temperature curing transfer mark having a top clear layer containing a large amount of isocyanate curing agent. However, in this transfer mark, the surface strength is improved by adding a large amount of isocyanate curing agent to increase the crosslink density, so that curing progresses during storage and is necessary when pasting on a cubic surface. It is difficult to maintain the elongation property, which is not practical.

  Furthermore, instead of sanding the surface of the adherend, an attempt to increase adhesion and stabilize by increasing wettability by oxidation treatment such as atmospheric pressure plasma or vacuum ultraviolet irradiation with an excimer lamp is disclosed in Patent Document 5, for example. However, it has not been implemented for the application of a heat transfer sheet.

JP-A-7-156530 JP-A-9-277791 No. 4-10073 Japanese Patent Publication No. 7-85943 JP 2001-64419 A JP-A-10-277479

  The present invention has been made in view of the above problems, and has sufficient durability (scratch resistance, scratch resistance) for use outdoors without performing overcoat coating, and has a glossy surface. A heat transfer sheet that has a high-class feel, is excellent in decorating properties, can be applied to a large-area cubic curved surface, has a low temperature required for adhesive curing of the heat transfer sheet, and can be used on an adherend with low heat resistance. The purpose is to provide.

  Another object of the present invention is to provide a method for firmly attaching a heat transfer sheet excellent in such properties to an adherend easily and without forming air bubbles on the attachment surface. To do.

  The heat transfer sheet of the present invention that solves the above problems is a heat-sensitive transfer sheet having a release mount, a heat-sensitive adhesive layer, a colored ink layer, and a transparent clear layer, and the heat-sensitive adhesive constituting the heat-sensitive adhesive layer is a curing agent. And a blocked isocyanate which starts reaction at 60 ° C. or more and 80 ° C. or less, and the transparent clear layer is cured by ultraviolet irradiation so that the surface hardness is H or more in pencil hardness. It is characterized by becoming.

  In the heat-sensitive transfer sheet of the present invention, a blocked isocyanate that starts reaction at 60 ° C. or higher and 80 ° C. or lower is used as a heat-sensitive adhesive curing agent. However, the elongation characteristics of the thermal transfer sheet are not deteriorated, the followability to the cubic surface is always excellent, and the curing proceeds at a low temperature of 100 ° C. or lower, so that the adherend is heated to a high temperature such as plastic. Even those that cannot be heated can be applied with sufficient strength. In addition, the surface of the adherend is oxidized by atmospheric pressure plasma irradiation, ultraviolet irradiation, corona discharge treatment, arc discharge treatment, low pressure plasma treatment, low pressure mercury lamp irradiation treatment, flame treatment, or intro treatment, and the like. When the wettability is 42 mN / m or more, particularly strong sticking can be achieved.

  In addition, the heat-sensitive transfer sheet of the present invention is formed with an ultraviolet curable transparent clear ink in which the transparent clear layer is cured by ultraviolet irradiation, so that it is durable enough to be used outdoors without overcoating. It has a property (scratch resistance, scratch resistance), has a glossy surface, and can be decorated with a high-class feeling.

  Examples of the heat transfer sheet of the present invention include a layer structure in which a heat-sensitive adhesive layer, a colored ink layer, and a transparent clear layer are laminated in this order on a release mount.

  In the present invention, it is preferable that a protective sheet layer is further laminated on the ultraviolet-cured transparent clear layer. The protective sheet is provided so as to be peelable from the transparent clear layer. The protective sheet protects the transparent clear layer until the heat-sensitive transfer sheet is applied to the adherend, and functions as a temporary support for the colored ink layer during application. In the case where printing is performed separately on the heat-sensitive transfer sheet, the design can be transferred to the adherend while maintaining the printing position of each design.

  Moreover, as for the heat transfer sheet of the present invention, the layer structure is such that a transparent clear layer, a colored ink layer, and a heat-sensitive adhesive layer are laminated in this order on a release mount.

  In addition, the method of applying the heat-sensitive transfer sheet of the present invention is a method in which the surface of the adherend is surface treated so that the wettability of the surface is 42 mN / m or more, and then the heat-sensitive transfer sheet of the present invention is immersed in water and peeled off. The heat-sensitive transfer layer is peeled off from the mount and the heat-sensitive adhesive layer of the heat-sensitive transfer sheet is attached to the surface-treated adherend.

  Further, when the layer structure of the heat-sensitive transfer sheet of the present invention is such that a transparent clear layer, a colored ink layer, and a heat-sensitive adhesive layer are laminated in this order on a release mount, It is characterized in that the wettability of the surface is set to 42 mN / m or more by treatment and then wetted with water, and the heat-sensitive adhesive layer of the heat-sensitive transfer sheet is adhered to the surface-treated adherend.

  In the present invention, when the wettability of the surface of the adherend is set to 42 mN / m or more, the adherend is wetted with water. In addition, the heat-sensitive transfer sheet can be firmly attached without sanding the adherend.

  As the surface treatment method, atmospheric pressure plasma irradiation, vacuum ultraviolet irradiation with an excimer lamp, corona discharge treatment, arc discharge treatment, low pressure plasma treatment, low pressure mercury lamp irradiation treatment, flame treatment, intro treatment and the like are preferable.

As described above, the present invention has the following effects.
(1) After the heat transfer sheet is attached to the adherend, the pencil hardness is H by 100 ° C. or less, preferably 90 ° C. or less, more specifically 75 to 80 ° C. without using overcoat coating. It has a scratch resistance and scratch resistance of ˜4H, and can be decorated with a high glossiness of 75% or more.
(2) By irradiating the adherend with atmospheric pressure plasma or vacuum ultraviolet rays using an excimer lamp, the wettability becomes 42 mN / m or more without sanding the adherend surface, and the heat transfer sheet is slippery because it gets wet with water. As a result, the attachment becomes easy, the air is not involved, and the adhesive strength is improved.
(3) There is no change in the quality of the heat transfer sheet even after long-term storage, and it can always be satisfactorily applied to a cubic surface.
(4) Since the heat transfer sheet can be thermally bonded at a temperature of 100 ° C. or lower, the heat transfer sheet is affixed with sufficient strength even to an adherend that cannot be heated to a high temperature such as plastic. be able to.
(5) Since no overcoat coating is required, there is no defective process itself, and the effects of cost reduction and production time reduction can be obtained.

Hereinafter, the heating transfer sheet and the method for attaching the heating transfer sheet of the present invention will be described in detail.
FIG. 1 is a schematic cross-sectional view showing a typical layer structure of a heat transfer sheet in the present invention. FIG. 2 is a schematic cross-sectional view showing another layer configuration of the heat transfer sheet in the present invention. FIG. 3 is a schematic cross-sectional view showing still another layer configuration of the heat transfer sheet in the present invention. 1-3, 1 is a transfer mount, 2 is a release layer, 3 is a heat-sensitive adhesive layer, 4 is a colored ink layer, 5 is a transparent clear layer, and 6 is a protective film layer.

  Each configuration of the heat transfer sheet of the present invention will be specifically described with reference to FIG. In the heat transfer sheet of FIG. 1, a heat-sensitive adhesive layer 3, a colored ink layer 4, a transparent clear layer 5, and a protective film layer 6 are provided in this order on a release layer 2 of a transfer mount 1.

  First, as the transfer mount 1 of the heat-sensitive transfer sheet of the present invention, any sheet can be used as long as the heat-sensitive adhesive layer 3, the transparent clear layer 5, and the protective film layer 6 can be peeled off. The release layer 2 is not required as long as the transfer board itself has releasability. Specifically, paper, cloth, foil, film or the like is used as a mount, and a release layer 2 is formed by performing a release treatment such as silicone, polyethylene, wax, paraffin, or directly on the mount substrate. Or what apply | coated peeling layer 2, such as a water release agent containing re-wet pastes, such as dextrin or carboxymethylcellulose (CMC), can be used after the said peeling process.

  The heat-sensitive adhesive layer 3 comprises 5 to 100 blocked isocyanates capable of initiating a reaction at 60 ° C. or more and 80 ° C. or less with respect to 100 parts by weight of at least one main component resin selected from polyurethane resin, polyester resin or acrylic resin. It is composed of a composition having a weight, preferably 10 to 50 parts by weight, having adhesiveness at room temperature and capable of printing, preferably screen printing. The main component resin preferably has a glass transition point (Tg) of 20 ° C. or lower and an OH value in the range of 5 to 100 in order to achieve normal temperature adhesiveness.

  Specific examples of the polyurethane resin having such characteristics include, for example, trade names: Nipporan (Nippon Polyurethane Industry), Barnock (Dainippon Ink Industry), Resamine (Daiichi Seika).

  In addition, as polyester resins having the above characteristics, saturated polyesters marketed under the trade names: Byron (Toyobo), Stuffix (Fuji Photo Film), Elite (Unitika), Hitaroid, Espel (Hitachi Chemical), etc. Examples thereof include resins and alkyd resins.

  Examples of the acrylic resin include a thermoplastic acrylic resin and a thermosetting acrylic resin, which are commercially available as trade names: Acridic (Dainippon Ink and Chemicals), Dainar (Mitsubishi Rayon), and SK Dyne (Soken Chemical).

  On the other hand, in this invention, a hardening | curing agent is block isocyanate which a hardening reaction starts at 60 degreeC or more and 80 degrees C or less, specifically, brand name: Duranate (Asahi Kasei Chemicals) etc. are mentioned.

  The heat-sensitive adhesives optionally include auxiliary additives commonly used in printing inks such as screen printing inks, such as antifoaming agents, leveling agents, thickeners, fillers, and diluting solvents. You may add arbitrarily within the range which does not inhibit performance, such as adhesiveness of an adhesive bond layer, and sclerosis | hardenability. Furthermore, a catalyst for lowering the dissociation temperature of the blocked isocyanate, a catalyst for promoting the reaction, and the like can be appropriately added.

  The heat-sensitive adhesive layer is formed by, for example, screen printing the heat-sensitive adhesive on a release board. As a printing method, screen printing is preferable, but other printing methods may be used. The thickness of the coating film is usually 3 to 50 μm, preferably 5 to 10 μm. If the film thickness of the heat-sensitive adhesive layer is thinner than 3 μm, the initial adhesive strength is particularly insufficient, and if it is thicker than 50 μm, the surface smoothness is inferior and it is not economical.

  As the colored ink layer 4, most known commercially available colored or non-colored printing inks such as screen inks can be used. Among these inks, those having a two-component reaction type and using an isocyanate curing agent as a curing agent are particularly preferable. By using blocked isocyanate as a curing agent, flexibility can be maintained until transfer, and it can be cured after heating to give durability. For example, 100 parts by weight of an epoxy resin is blended with 10 to 50 parts by weight of the blocked isocyanate that starts the curing reaction at 60 ° C. or more and 80 ° C. or less, and a binder is added thereto. Things can be printing inks. In addition, metal powder such as aluminum and copper, glass powder, film strips such as a film having a hologram layer, and one or more kinds of glitters stripping a film having a reflective metal thin film layer are added. Also good. Auxiliary additives such as antifoaming agents, leveling agents, thickeners, fillers, and diluting solvents can be added to the printing ink as long as the ink performance is not impaired. If necessary, a catalyst for lowering the dissociation temperature of the blocked isocyanate, a catalyst for promoting the reaction, or the like may be added.

  The colored ink layer may be formed by any known printing method, but is preferably formed by screen printing. The colored ink layer may consist of one layer, or two or more layers may be overprinted to form a multicolor pattern.

  The transparent clear layer 5 is formed in order to increase the scratch resistance and scratch resistance of the sheet itself and maintain the durability. As a material for forming the transparent clear layer, a known commercially available UV-curable transparent clear is used. Any one can be used as long as the pencil hardness of the surface is H or higher and the elongation of the heat transfer sheet after printing and curing of this clear is 5 to 50%. Examples of commercially available UV curable transparent clears having such properties include trade names: UVSPS5300 Clear (Imperial Ink Manufacturing), UC410OC Clear (Seiko Advance), and the like. These UV-curable transparent clears usually comprise a polymerizable monomer or oligomer, a resin or oligomer that serves as a binder, a photopolymerization initiator, and additives that are added as necessary. Further, a composition having the same performance as described above, for example, a composition obtained by adding 0.1 to 10 parts by weight of a photopolymerization initiator to a mixture of 100 parts by weight of a polymerizable urethane oligomer and 0 to 35 parts by weight of a polymerizable acrylic monomer. Also used is a product added with defoamers, leveling agents, thickeners, UV absorbers, fillers, organic solvents for viscosity adjustment, etc., which are auxiliary additives usually used in printing, for example, screen printing it can

  These transparent clears are printed by printing, preferably screen printing, and can be laminated by curing by irradiating with ultraviolet rays by a metal halide lamp. The film thickness is 2 to 50 μm, preferably 5 to 30 μm. Printing is performed at least on the colored ink layer in a range covering the heat-sensitive adhesive layer.

  In addition, a solvent dry type or two-component reaction type clear that is not an ultraviolet curable type has insufficient surface hardness and takes time to dry and harden. Therefore, in a normal working time, a protective film layer laminated thereon It is difficult to obtain a glossiness of 75% or more by partially dissolving the surface of the clear layer in the ink solvent.

  The protective film layer 6 can be omitted for reasons such as the size of the pattern and the shape of the adherend, but it is generally applied from the viewpoint of workability at the time of attachment. As a material for forming the protective film layer, any flexible resin that can be easily peeled off from the transparent clear layer 5 can be used. For example, 100 parts by weight of polyester resin such as acrylic resin, saturated polyester resin, alkyd resin, vinyl chloride resin or vinyl chloride-vinyl acetate copolymer resin, phthalate ester, adipate ester, azelate ester, etc. It is preferable to use a plasticizer for plastic, which is used alone or in combination of 10 to 30 parts by weight in combination of two or more. As a more preferable composition, 10 to 30 parts of a plasticizer is added to 100 parts by weight of an acrylic resin having a glass transition point in the range of 30 ° C. to 75 ° C., and a filler, an antifoaming agent and a diluent solvent are added as appropriate. Composition. Further, a colorant such as a color pigment or a dye may be added to the protective film layer so that peeling of the protective film layer can be confirmed.

  The protective film layer preferably has an elongation of 30% or more at room temperature, more preferably in the range of 30 to 500%, from the viewpoint of ensuring followability to an adherend having a curved surface structure and good releasability. It is. When the protective film layer has an elongation of less than 30%, the followability to the adherend having a curved surface structure is significantly impaired, and when the protective film layer is peeled off, it is easily broken and difficult to remove cleanly. . On the other hand, when the elongation percentage exceeds 500%, there is a problem that the pattern is distorted in handling, pasting, etc., and it is not preferable in terms of work to form a layer thickness to prevent this, and an ink solvent for a protective film May adversely affect seat performance.

  To the protective film layer, beads such as acrylic resin, styrene resin, polyolefin resin, and nylon resin having an average particle diameter of 1 to 50 μm are added so that the squeegee moves smoothly when the heat-sensitive transfer sheet is attached to the adherend. You can also. In addition, for example, auxiliary additives used in normal screen printing, such as an antifoaming agent, a leveling agent, a thickening agent, a diluting solvent, etc. can be optionally added within a range not impairing the performance of the protective film. .

  These protective film layer forming compositions are printed by a printing method, preferably a screen printing method, and laminated on the transparent clear layer 5. The film thickness is 10 to 100 μm, preferably 30 to 70 μm.

  FIG. 2 shows an example of a thermal transfer sheet in which the protective film layer 6 is not provided. The heat-sensitive transfer sheet of FIG. 2 has the same layer structure as that of the heat-sensitive transfer sheet of FIG. 1 except that no protective film layer is provided. In the present invention, the protective film layer is used for improving workability at the time of pasting and for preventing the transparent clear layer from being scratched during storage. It is not necessarily required depending on the shape of the kimono and the storage form.

  FIG. 3 shows another example of the thermal transfer sheet of the present invention. This heat-sensitive transfer sheet is formed by laminating a transparent clear layer 5, a colored ink layer 4, and a heat-sensitive adhesive layer 3 in this order on a release mount. The material of the release mount used should be a smooth film. Thus, the surface gloss after transfer can be made extremely high of 80% or more. Moreover, it can affix also to a cubic curve instead of the protective film 6 shown in FIG. 1 by using what has the elongation rate of the film to be used 30% or more, Preferably it is the range of 30-500%. Preferred films for use include, but are not limited to, polyethylene films, unstretched polypropylene films, soft PVC films, urethane films and the like. Since other methods and materials for constituting each layer are the same as those of the thermal transfer sheet of FIG. 1, the description thereof is omitted.

When the thermal transfer sheet of the present invention is attached to an adherend, the thermal transfer sheet is peeled off from the release mount and attached to the adherend. Hereinafter, the method for applying the heat-sensitive transfer sheet to the adherend will be described by taking the heat-sensitive transfer sheet of FIG. 1 as an example.
First, the adherend is pretreated to at least 42 mN / m. The pretreatment is preferably an oxidation treatment by atmospheric pressure plasma irradiation or vacuum ultraviolet irradiation by an excimer lamp, but other treatment methods such as corona discharge treatment, arc discharge treatment, low pressure plasma treatment, low pressure mercury lamp irradiation treatment, flame treatment, It may be by intro processing.

  On the other hand, the heated transfer sheet is temporarily placed with the heat-sensitive adhesive layer side of the heated transfer sheet as the adherend side on the adherend that has been dipped in a water tank and peeled off from the transfer mount and wetted with water. Then, it is temporarily bonded while extruding water using a rubber spatula or squeegee. Thereafter, heating at 100 ° C. or lower, preferably 90 ° C. or lower, more specifically 75 to 80 ° C. is performed, and after cooling, the protective film is peeled off to obtain a durable high gloss pattern.

  In addition, about the thermal transfer sheet of FIG. 2, a thermal transfer sheet can be transcribe | transferred and stuck to a to-be-adhered body by the same method except not peeling of a protective film layer.

  In addition, the thermal transfer sheet of FIG. 3 can be transferred and pasted in the same manner as the thermal transfer sheet of FIG. 2, but when a film is used for the mount and a release treatment agent other than water-soluble is used for the release layer. Without immersing the thermal transfer sheet in a water bath, the thermal adhesive sheet side of the thermal transfer sheet is temporarily placed directly on the adherend that has been wetted with water as the adherend side, and a rubber spatula or squeegee is placed. It is possible to obtain a highly glossy pattern by temporarily adhering while extruding water using, etc., and then heating similarly to the heat-sensitive transfer sheet of FIG.

  The adherend to which the heat-sensitive transfer sheet of the present invention is attached is preferably a metal, plastic or the like. These materials may be coated on the surface. Examples of such adherends include, but are not limited to, automobiles, motorcycles, boats, fishing gear, golf clubs, rackets, toys, helmets, vending machines, and the like.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples.

Example 1
A resin coating surface of a transfer board coated with a water-soluble resin, blended with 100 parts by weight of polyester resin (Esper 9940, manufactured by Hitachi Chemical Co., Ltd.) and 15 parts by weight of blocked isocyanate (Duranate MF-K60X, manufactured by Asahi Kasei Chemicals) as a heat-sensitive adhesive. A composition obtained by appropriately adding an antifoaming agent and a diluting solvent was printed by screen printing to form a heat-sensitive adhesive layer.

  On the obtained heat-sensitive adhesive layer, 100 parts by weight of white ink (SG740 made by Seiko Advance) and 15 parts by weight of blocked isocyanate (Duranate MF-K60X made by Asahi Kasei Chemicals) were blended into an antifoaming agent and a diluent solvent. The composition added as appropriate was printed by screen printing to form a colored ink layer.

  On the obtained colored ink layer, an ultraviolet curable transparent clear (UVSPS5300 clear manufactured by Teikoku Ink Manufacturing Co., Ltd.) was printed by screen printing, two 80 W / cm metal halide lamps, a lamp height of 15 cm, and a belt speed of 8 m / min. The film was dried by irradiating with ultraviolet rays under the conditions to form a transparent clear layer.

  Compound obtained by dissolving 20 parts by weight of dibutyl phthalate (DBP) and 20 parts by weight of polypropylene glycol in 150 parts by weight of xylene on 100 parts by weight of acrylic resin (Dianar BR106 manufactured by Mitsubishi Rayon) on the transparent clear layer thus obtained. Was printed by screen printing to form a protective film layer and dried overnight at room temperature to obtain a heat transfer sheet.

  For the adherend, a resin-coated plate irradiated with plasma gas using an atmospheric pressure plasma apparatus was used. The heated transfer sheet was immersed in a water tank, peeled off from the transfer mount, temporarily placed on an adherend wetted with water, and temporarily adhered while extruding water using a rubber spatula. Thereafter, heating was performed at 80 ° C. for 20 minutes, and the protective film was peeled off after cooling. Next, the adhesion, surface gloss, and surface height of the attached heat-sensitive transfer sheet were evaluated. Evaluation was performed by the following evaluation method. The results are shown in Table 1.

(Evaluation of adhesion)
Using a Nichiban cello tape (registered trademark), a tape test (1 mm square, 10 × 10) of the attached heat-sensitive transfer sheet was performed, and the evaluation was performed based on the number of grids peeled off. ○ indicates that the number of peeled grids is 0, and x indicates that the number of peeled grids is 1 to 100. Δ indicates that the evaluation of ○ is mixed with the evaluation of × due to the difference in the coating color of the adherend.

(Evaluation of surface gloss)
The glossiness of the affixed heat-sensitive transfer sheet was measured using a gloss meter and evaluated.

(Evaluation of surface hardness)
Evaluation was performed by a pencil hardness test method.

Example 2
In Example 1, an ultraviolet curable transparent clear was added to 100 parts by weight of a polymerizable urethane oligomer (EBECRYL230 manufactured by Daicel Cytex), 10 parts by weight of a polymerizable acrylic monomer (NK ester A-HD-N manufactured by Shin-Nakamura Chemical), and light. A composition in which 2 parts by weight of a polymerization initiator (Ciba Specialty Chemicals Irgacure 1800) and 2 parts by weight of an ultraviolet absorber (Ciba Specialty Chemicals Tinuvin 384-2) are added to an antifoaming agent as appropriate. A heat transfer sheet was prepared in the same manner as in Example 1 except that. The sticking to the adherend was also performed in the same manner as in Example 1. Evaluation of the attached heat-sensitive transfer sheet was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 3
On the polyethylene sheet (RFE100N (ko-2) manufactured by Sanei Kaken Co., Ltd.) on which the release treatment layer was formed, an ultraviolet curable transparent clear (UVSPS5300 clear manufactured by Teikoku Ink Co., Ltd.) was printed by screen printing. Ultraviolet irradiation was performed under the conditions to form a transparent clear layer. A white ink (UVIPO manufactured by Teikoku Ink Manufacturing Co., Ltd.) is printed on the obtained transparent clear layer by screen printing, and is irradiated with ultraviolet rays under the same conditions as when the transparent clear layer of Example 1 was formed. An ink layer was formed.

  On the obtained colored ink layer, the composition of the heat-sensitive adhesive used in Example 1 was printed by screen printing in the same manner as in Example 1 to form a heat-sensitive adhesive layer, and a heat transfer sheet was prepared. . Adhesion to the adherend does not immerse the heat-sensitive transfer sheet in the water layer, but directly attaches the heat-sensitive adhesive layer side of the heat-sensitive transfer sheet to the pre-treated and wetted water. Temporarily placed on the body side, temporarily adhered in the same manner as in Example 1 while extruding water using a rubber spatula or squeegee, and further heated in the same manner. After cooling, the film mount was peeled off to perform transfer. The attached heat-sensitive transfer sheet was also evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
The heat transfer sheet was the same as in Example 1 except that the curing agent blended in the heat-sensitive adhesive in Example 1 was replaced by 8 parts by weight of melamine resin (Nippon Cytec Industries' Cymel 254) instead of blocked isocyanate. The same was applied to the adherend. Evaluation of the attached heat-sensitive transfer sheet was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
In Example 1, instead of UV curable transparent clear, 100 parts by weight of clear ink (SG740 medium manufactured by Seiko Advance) and 15 parts by weight of blocked isocyanate (Duranate MF-K60X manufactured by Asahi Kasei Chemicals) were added to an antifoaming agent, A heat transfer sheet was prepared in the same manner as in Example 1 except that a composition to which a diluting solvent was appropriately added was used. The sticking to the adherend was also the same as in Example 1. Evaluation of the attached heat-sensitive transfer sheet was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3
In Example 1, instead of the ultraviolet curable transparent clear, 100 parts by weight of an epoxy resin (YD-171 manufactured by Tohto Kasei) and 10 parts by weight of a melamine resin (Cymel 254 manufactured by Nippon Cytec Industries) were mixed with an antifoaming agent, A heat transfer sheet was prepared in the same manner as in Example 1 except that a composition to which a diluting solvent was appropriately added was used. The sticking to the adherend was also the same as in Example 1. Evaluation of the attached heat-sensitive transfer sheet was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4
The heat transfer sheet prepared in Example 1 was attached using an untreated resin-coated plate. Evaluation of the attached heat-sensitive transfer sheet was performed in the same manner as in Example 1. The results are shown in Table 1.

  From Table 1, in Examples 1, 2, and 3 using a low-temperature-crosslinked blocked isocyanate as a curing agent for a heat-sensitive adhesive, good adhesion was obtained even at a relatively low temperature of 80 ° C. On the other hand, in the case of Comparative Example 1 using a conventional melamine resin as the curing agent, good adhesiveness was obtained at a temperature of 100 ° C. or higher, but melamine crosslinking hardly progressed at 80 ° C. Sex was insufficient.

  Further, if an extensible UV-curing clear is used for the transparent clear layer and UV-crosslinked in advance, as shown in Examples 1, 2, and 3, good surface gloss and surface with a glossiness of 75% or more are obtained. Hardness could be obtained. In particular, in the heat-sensitive transfer sheet of Example 3 in which a smooth film was used as the release mount and a transparent clear layer was provided on this film, a very good surface gloss exceeding 80% gloss could be obtained. On the other hand, in the case of Comparative Examples 2 and 3 in which the same resin composition as the ink or heat-sensitive adhesive is used for the transparent clear that is normally employed for the heat transfer mark of the overcoat coating specification, sufficient surface gloss is obtained. In addition, it was found that the surface hardness was as soft as pencil hardness HB, and scratch resistance and scratch resistance were not obtained.

  Furthermore, in Examples 1, 2, and 3, the surface of the adherend to which the heat transfer sheet is adhered is subjected to surface oxidation treatment such as plasma irradiation treatment so as to be in a uniform and highly wettable state. Stable adhesion was obtained regardless of conditions and conditions. On the other hand, in the case of Comparative Example 4 in which the plasma treatment was not performed, it was confirmed that the wettability was lowered depending on the state of the adherend, and the evaluation of adhesion was uneven.

It is typical sectional drawing of the heat-sensitive transfer sheet of one Example of this invention. It is typical sectional drawing of the heat-sensitive transfer sheet of the other Example of this invention. It is typical sectional drawing of the heat-sensitive transfer sheet of the further another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer mount 2 Release layer 3 Heat sensitive adhesive layer 4 Colored ink layer 5 Transparent clear layer 6 Protective film layer

Claims (7)

  In a heat-sensitive transfer sheet having a release mount, a heat-sensitive adhesive layer, a colored ink layer, and a transparent clear layer, the heat-sensitive adhesive constituting the heat-sensitive adhesive layer is a block that starts a reaction at 60 ° C. or more and 80 ° C. or less as a curing agent A heat-sensitive transfer sheet comprising an isocyanate, and a transparent clear layer formed by an ultraviolet curable transparent clear ink having a surface hardness of H or higher in terms of pencil hardness, which is cured by ultraviolet irradiation.   2. The heat-sensitive transfer sheet according to claim 1, wherein a heat-sensitive adhesive layer, a colored ink layer, and a transparent clear layer are laminated in this order on the release mount.   The heat-sensitive transfer sheet according to claim 2, wherein a protective sheet layer is further laminated on the ultraviolet-cured transparent clear layer.   2. The heat-sensitive transfer sheet according to claim 1, wherein a transparent clear layer, a colored ink layer, and a heat-sensitive adhesive layer are laminated in this order on the release mount.   After the surface of the adherend is treated so that the wettability of the surface is 42 mN / m or more, the thermal transfer sheet according to any one of claims 1 to 3 is dipped in water, and the thermal transfer sheet is peeled off from the release mount. Then, a heat-sensitive transfer sheet sticking method, wherein the heat-sensitive adhesive layer of the heat-sensitive transfer sheet is attached to the surface-treated adherend.   The surface of the adherend is subjected to surface treatment, and the surface of the heat-sensitive adhesive layer of the heat-sensitive transfer sheet according to claim 4 is wetted with water after the surface is treated to have a wettability of 42 mN / m or more. A method for applying a heat-sensitive transfer sheet, comprising:   The surface treatment of the adherend is characterized by atmospheric pressure plasma irradiation, vacuum ultraviolet irradiation with an excimer lamp, corona discharge treatment, arc discharge treatment, low-pressure plasma treatment, low-pressure mercury lamp irradiation treatment, flame treatment, or intro treatment. The sticking method of the heat-sensitive transfer sheet according to claim 5 or 6.

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