JP6587062B2 - Thermal transfer recording medium used for thermal transfer decoration system - Google Patents

Description

The present invention relates to a thermal transfer recording medium used in a thermal transfer decoration method for obtaining a thermal transfer recording material having a metallic luster colored when viewed from the opposite side of the side thermally transferred to a transparent image receptor such as glass.

Conventionally, as a method for obtaining an image having a colored metallic luster using a thermal transfer recording apparatus, for example, there is a method introduced in Patent Document 1. According to this, first, an image is first transferred with a thermal transfer recording medium provided with a metal vapor deposition layer, and then the image is overlaid and transferred with a thermal transfer recording medium provided with a colored layer, thereby obtaining an image having a colored metallic luster. ing.

In recent years, in devices consisting of flat displays such as smartphones and tablet terminals, all images are imaged using a thermal transfer recording medium in order to display the manufacturer's logo, model name, etc. with a metallic luster when viewed from the display surface. There is a potential need to transcribe.

This method has the following advantages. That is, 1. When a thermal transfer recording apparatus using a thermal head is used as an apparatus for transferring an image, an image pattern can be set freely, which is advantageous for producing a small number of copies.
2. By separating the thermal transfer recording medium provided with the colored layer and the thermal transfer recording medium provided with the metallic gloss layer, the degree of freedom in image design is increased. For example, it is possible to easily obtain an image such that the manufacturer logo is gold and the model name is silver.
3. By making the side on which the transfer of the transparent image receptor has not been performed the front side of the device, the image having the metallic luster becomes the inside of the device as compared with the method described in Patent Document 1, and the image is stained or damaged. You can keep the beauty for a long time.

From the viewpoint of obtaining the above merits, the present inventor examined the following thermal transfer decoration method using a conventionally known thermal transfer recording medium.
1) An image is transferred to a transparent image receptor such as glass using a first thermal transfer recording medium in which at least a colored layer is provided on a substrate.
2) The image is overlaid and transferred using the second thermal transfer recording medium in which at least a metal vapor deposition layer and an adhesive layer are provided on the substrate.
3) Further, the image is transferred onto the image with a third thermal transfer recording medium in which at least a black masking layer is provided on the substrate. In some cases, the image is further transferred onto another thermal transfer recording medium. This is because when the transparent image receptor is viewed from the surface opposite to the surface on which the transfer has been performed, light passes through the images formed on the first and second thermal transfer recording media. In order to prevent the metallic luster from becoming weak, the transfer is performed by superimposing the second thermal transfer recording medium on the second thermal transfer recording medium.
4) A colored metallic gloss image is obtained by viewing the transparent image receptor from the surface opposite to the surface on which the transfer has been performed.

However, as the first thermal transfer recording medium, a conventionally known thermal transfer recording medium in which a heat-resistant slipping layer is provided on one side of the substrate and a colorant-containing adhesive layer as a colored layer is provided on the other side is used. In this case, coloring is performed when the second thermal transfer recording medium is used for overtransfer from the image onto which the coloring material-containing adhesive layer as the colored layer is transferred, or when the third thermal transfer recording medium is further transferred from there. The surface of the colorant-containing adhesive layer as a layer was damaged by the heat during the repeated transfer, resulting in a fine uneven state, resulting in a problem that the metallic luster appeared dull.

On the other hand, in the system disclosed in Patent Document 1, first, a thermal transfer layer in which a heat-resistant slipping layer is provided on one surface of a substrate and a release layer, an anchor layer, a metal vapor deposition layer, and an adhesive layer are provided in this order on the other surface. An image is formed by thermal transfer using a recording medium, and then an image is formed by thermal transfer using a thermal transfer recording medium having a colored layer. That is, since an image that is easily melted by heat is formed on an image having a hard base, unlike the present decoration method, a problem that the metallic luster appears dull in the final image hardly occurs.

However, in the method in Patent Document 1, first, an image having a metallic gloss is transferred to an image receiver, and a colored layer is transferred from the image to the image receiving body. Therefore, an uncolored metallic gloss layer faces the image receiving side. . For this reason, a colored metallic gloss image cannot be obtained by the method of transferring to a transparent image receptor and viewing from the opposite side. When viewed from the transfer side, a colored metallic gloss image can be obtained. Is not obtained, and it is difficult to maintain the beauty of the transcript for a long time.

Therefore, as a result of earnest research, the present inventor has found that the first thermal transfer recording medium is a heat-resistant slipping layer on one side of the substrate, and at least a heat-resistant release layer and a colorant-containing adhesive layer on the other side. By using the thermal transfer recording medium provided with the above in this order, it was found that the phenomenon of dull metallic luster can be eliminated even in the thermal transfer decoration method of the present invention, and the present invention was completed.

JP-A-9-39399

Using a first thermal transfer recording medium in which a transparent image receptor such as glass is provided with a heat-resistant slipping layer on one side of a substrate and at least a heat-resistant release layer and a colorant-containing adhesive layer on the other side in this order After forming an image by thermal transfer, a second thermal transfer recording medium is used in which a heat-resistant slipping layer is provided on one surface of the substrate, and at least a metal vapor deposition layer and an adhesive layer are provided on the other surface in this order. An image is formed by thermal transfer, and further, thermal transfer is performed using a third thermal transfer recording medium on which a heat-resistant slipping layer is provided on one side of the substrate and at least a black masking layer is provided on the other side. A second thermal transfer recording medium in a thermal transfer decoration system that forms an image by superimposing and obtains a metallic glossy image when the transparent image receptor is viewed from the surface opposite to the surface to which the image is transferred. Or metallic gloss even when images are overlaid and transferred on a third thermal transfer recording medium Not Kusuma in thermal damage, providing a first thermal transfer recording medium.

In the first aspect of the invention, the heat-resistant slipping layer is formed on one surface of the substrate, and at least the fibrous or needle-like alumina hydrate particles defined by an aspect ratio (major axis / minor axis) of 30 to 5000 on the other surface or This is a thermal transfer recording medium in which a heat-resistant release layer containing alumina particles as main components and a colorant-containing adhesive layer are provided in this order.

A second invention is the thermal transfer recording medium according to the first invention, wherein the alumina hydrate particles or the alumina particles have a minor axis of 1 to 10 nm and a major axis of 100 to 10,000 nm.

The third invention is characterized in that the heat-resistant release layer of the thermal transfer recording medium is composed of the alumina hydrate particles or alumina particles and a resin, and the alumina hydrate particles or alumina particles are 60% by weight or more. The thermal transfer recording medium according to the first or second invention.

A fourth aspect of the present invention is the thermal transfer recording medium according to any one of the first to third aspects, wherein the heat-resistant release layer of the thermal transfer recording medium has a thickness of 0.1 μm to 0.6 μm. It is.

An image is formed by the first thermal transfer recording medium having the heat-resistant release layer and the colorant-containing adhesive layer of the present invention, and a second thermal transfer recording medium provided with a metal vapor deposition layer on the image, and further black concealment Even when an image is overlaid and transferred by thermal transfer on a third thermal transfer recording medium provided with a layer, the image surface of the first thermal transfer recording medium is not easily deformed by heat during transfer, and the phenomenon of dull metallic luster is eliminated. I was able to.

The first thermal transfer recording medium used in the decorating method of the present invention is provided with a heat-resistant slipping layer on one surface of a substrate and at least a heat-resistant release layer and a colorant-containing adhesive layer on the other surface in this order. The second thermal transfer recording medium is a thermal transfer recording medium in which a heat-resistant slipping layer is provided on one side of a substrate, and at least a metal vapor deposition layer and an adhesive layer are provided in this order on the other side. The third thermal transfer recording medium is a thermal transfer recording medium in which a heat-resistant slipping layer is provided on one side of a substrate and at least a black concealing layer is provided on the other side.
(Receiver)

Since the transparent receiver in the present invention is installed on the display surface in a device including a flat display such as a smartphone or a tablet terminal, visibility and durability are required. For this reason, it is suitable that it is transparent and hard. Moreover, it is preferable that the thickness of the device is as thin as possible. Specifically, a hard glass plate having a thickness of about 0.3 to 1.0 mm, a transparent hard plastic plate such as an acrylic resin or a polycarbonate resin, or the like is preferably used.
(Base material)

As a base material used for the first thermal transfer recording medium, the second thermal transfer recording medium, and the third thermal transfer recording medium of the present invention, a polyester film such as a polyethylene terephthalate film or a polyethylene naphthalate film, a polycarbonate film Polyamide film, aramid film, and other various plastic films generally used as a base film for this type of thermal transfer recording medium can be used. In addition, high density thin paper such as condenser paper can be used. The thickness of the substrate is usually about 1 to 10 μm, and in order to improve heat transfer, a range of 1 to 6 μm is preferable.
(Heat resistant slipping layer)

As the material of the heat-resistant slip layer used in the first thermal transfer recording medium, the second thermal transfer recording medium, and the third thermal transfer recording medium of the present invention, those conventionally used in thermal transfer recording media. Can be used without particular limitation, for example, heat-resistant resins such as silicone resins, fluororesins, epoxy resins, melamine resins, phenol resins, polyimide resins, nitrocellulose resins, and other resins modified with the above heat-resistant resins ( For example, a silicone-modified urethane resin, a silicone-modified acrylic resin, or the like may be used. From the viewpoint of heat resistance against thermal heads, lowering the dynamic friction coefficient at high temperatures, and cost. Particularly preferred are modified urethane resins, silicone-modified acrylic resins, or mixtures thereof.

Moreover, you may mix | blend a lubricant with the heat-resistant slipping layer of this invention. Examples of the lubricant include silicone oils (for example, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, fluorine-containing silicone oil, and epoxy modification, alkyl modification, amino modification, carboxyl modification, alcohol modification, polyether modification, etc. Various modified silicone oils), aspartate esters, fluorosurfactants, phosphate esters, paraffin waxes, higher fatty acid amides, esters and metal salts that exhibit lubricity in the liquid state It is done.

You may mix | blend other additives, such as an antistatic agent, with the heat-resistant slipping layer of this invention.

The heat-resistant slip layer of the present invention can be formed by coating and drying a coating solution obtained by dissolving and dispersing the above components in an appropriate solvent. The coating thickness of the heat-resistant slipping layer (coating thickness after drying, hereinafter the same) is suitably in the range of 0.05 to 0.8 μm from the viewpoint of achieving a good anti-sticking effect and preventing deterioration of heat conduction. It is. If the thickness of the heat-resistant slipping layer is less than 0.05 μm, the heat resistance is insufficient and the thermal head heat causes sticking to the head during printing, or the recording medium melts with the base material due to heat, making printing impossible. It may become. When the thickness exceeds 0.8 μm, heat conduction may deteriorate and printing may be hindered.
(First thermal transfer recording medium)
(Coloring material-containing adhesive layer)

As the colorant-containing adhesive layer of the first thermal transfer recording medium of the present invention, a conventionally known thermal transfer ink layer comprising a heat-meltable or heat-softening vehicle and a colorant can be used without any particular limitation. As the vehicle, thermoplastic resins may be used alone or in combination of two or more. Moreover, you may use an additive suitably for a various objective.

Examples of the thermoplastic resin (including elastomer) include ethylene-vinyl acetate copolymer, ethylene-vinyl butyrate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid alkyl ester copolymer. Polymers, ethylene-acrylonitrile copolymers, ethylene acrylamide copolymers, ethylene copolymers such as ethylene-styrene copolymers, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl alcohol copolymers Vinyl chloride (co) polymers such as coalescence, (meth) acrylic acid ester resins, polyester resins, polyamide resins, epoxy resins, phenol resins, acetophenone-formaldehyde resins, cellulose resins, natural rubber, Styrene-butadiene copolymer, isoprene polymer, Ropuren polymers, petroleum resins, styrene resins, rosin resins, terpene resins, coumarone - indene resins, and thermoplastic polyurethane resins. These resins may be used alone or in combination of two or more.

Examples of the additive include a plasticizer, an antifoaming agent, a surfactant, and an antioxidant.

As the colorant, organic and inorganic color pigments and dyes generally used in the color layer of the thermal transfer recording medium can be used. In order to obtain a colored metallic glossy image, the colorant-containing color is used. Since the layer is required to have good light transmittance, a dye or an organic colored pigment is preferable. The content of the colorant in the colorant-containing colored layer is suitably 20 to 60% by weight.

The thickness of the colorant-containing adhesive layer is preferably in the range of 0.2 to 2.0 μm. When the thickness is less than 0.2 μm, it is difficult to obtain sufficient coloring power. If the thickness is greater than 2.0 μm, the transferability tends to be impaired.
(Heat-resistant release layer)

The heat-resistant release layer of the first thermal transfer recording medium contains fine alumina hydrate particles or alumina particles as main components.

The heat-resistant release layer of the first thermal transfer recording medium of the present invention requires not only heat resistance but also functional transparency. Furthermore, from the functional aspect of the release layer as a thermal transfer recording medium, the heat-resistant release layer is required to achieve both proper substrate adhesion and releasability from the substrate at the time of transfer, and not to reduce the cutting performance and thermal sensitivity. Is done. From the viewpoint of heat resistance and transparency, for example, colloidal inorganic particles such as silica, alumina, titanium oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, niobium oxide and the like can be mentioned. However, in general, these alone do not have the ability to form a self-supporting film and do not satisfy the function as the release layer.

On the other hand, high-aspect-ratio (major / minor) fibrous or needle-like alumina hydrate particles or an aggregated film of alumina particles forms a self-supporting film with heat resistance, flexibility and high transparency. It is known (Japanese Patent Laid-Open No. 2010-105846). In addition, it is known that the alumina hydrate particles or the aggregates of alumina particles and organic matter also form a self-supporting film having an orientation that is further prevented from cracking (Japanese Patent Laid-Open No. 2010-285315).

As described above, from the functional aspect of the release layer as the thermal transfer recording medium of the heat-resistant release layer of the present invention, compatibility between the substrate adhesion and releasability from the substrate at the time of transfer, and the cutting performance and heat at the time of thermal transfer are achieved. It is required not to reduce the sensitivity. From this viewpoint, it is preferable that the aspect ratio of the fibrous or needle-like alumina hydrate particles or alumina particles which are the main constituent components of the heat-resistant release layer is 30 to 5000. If the aspect ratio is less than 30, it is not preferable because the film formability is lowered and cracks are easily generated. On the other hand, when this aspect ratio exceeds 5000, the time required for the synthesis of the fibrous or needle-like alumina hydrate particles or alumina particles becomes long, so it is not practical. It is not preferable because transparency and flexibility are poor.

The alumina hydrate particles or alumina particles used in the present invention preferably have a minor axis of 1 to 10 nm and a major axis of 100 to 10,000 nm. When the average minor axis of the particles is less than 1 nm, since the particles are fine, the alumina hydrate particles or the dispersion of alumina particles are likely to aggregate, thereby increasing the viscosity and improving the storage stability. Since it falls, it is not preferable. If it is 10 nm or more, the flexibility of the resulting film is low. In order to obtain a self-supporting film having sufficient flexibility and strength, it is preferable that the major axis of the alumina hydrate particles or alumina particles is in the range of 100 nm to 10,000 nm. In this case, the major axis can take any one of these specific values.

There are various crystal forms of alumina. In the present invention, in order that the alumina particles have the above dimensions and the alumina thin film exhibits sufficient strength, the crystal form of the alumina particles is boehmite crystal form and / or Alternatively, it is preferable that the pseudo boehmite crystal form is a main component.

The alumina hydrate particles or alumina particles can be purchased as an aqueous or organic solvent sol solution from Kawaken Fine Chemical Co., Ltd.

The alumina hydrate particles or the heat-resistant release layer mainly composed of alumina particles used in the present invention can be used as the alumina hydrate particles or the alumina particle single layer. In addition, while maintaining the characteristics peculiar to inorganic substances such as a low coefficient of thermal expansion, the film strength, flexibility and transparency of the alumina hydrate particles or alumina particle films are further improved, and crack prevention viewpoints and substrates From the viewpoint of adjusting the adhesion to the film, a resin or a silane coupling agent can be added within a range not detracting from the heat resistance of the present invention.

As the resin, a conventionally known resin can be used. However, since the alumina hydrate particles or alumina particles are provided as a water-based or organic solvent-based sol as described above, the alumina hydrate particles Alternatively, a resin that does not break the dispersion of alumina particles is preferable. From this viewpoint, acrylic resins, methacrylic resins, butyral resins, epoxy resins, cellulose resins, polyamide resins, acetal resins, and the like are preferable.

Further, if necessary, as long as it does not break the dispersion of the alumina hydrate particles or alumina particles, as an adhesion regulator with the base material, epoxy resin, alicyclic hydrocarbon resin, ketone resin, styrene resin, A rosin resin, a polyester resin, a coumarone-indene resin, a phenol resin, a modified resin thereof, a silane coupling agent, or the like may be added.

In the case of the heat-resistant release layer composed of the alumina hydrate particles or alumina particles and the resin system of the present invention, the ratio of the alumina hydrate particles or alumina particles is the heat resistance and the cutting property during thermal printing. In view of the above, it is preferably 60% by weight or more.

Moreover, as said silane coupling agent, an epoxy group containing silane coupling agent, an amino group containing silane coupling agent, etc. are preferable. When the silane coupling agent is added to the alumina hydrate particles or alumina particle layer or the alumina hydrate particles or alumina particles and a layer composed of the resin system, the addition amount is in the heat-resistant release layer solid content. , And preferably 15% by weight or less. If it exceeds 15% by weight, the adhesion may be excessively increased and transferability may be affected.

The thickness of the heat resistant release layer is preferably 0.1 to 0.6 μm in a dry state. When the thickness is less than 0.1 μm, it is difficult to obtain a heat resistance effect. When the thickness exceeds 0.6 μm, the transfer sensitivity tends to decrease.

The second thermal transfer recording medium provided with a metal vapor deposition layer in the present invention is a thermal transfer recording medium in which a heat resistant slipping layer is provided on one surface of a substrate, and at least a metal vapor deposition layer and an adhesive layer are provided on the other surface in this order. In addition, a conventionally known thermal transfer recording medium can be used. Usually, a thermal transfer recording medium in which a release layer, a metal vapor deposition layer, and an adhesive layer are provided in this order on the other surface is used.

As a material for the release layer and the adhesive layer, a conventionally known thermal transfer ink layer made of a heat-meltable or heat-softening vehicle can be used without any particular limitation. As the vehicle, thermoplastic resins and waxes may be used alone or in combination of two or more. As the thermoplastic resin, the thermoplastic resins listed in the description of the colored layer in the first thermal transfer recording medium may be used alone or in combination of two or more. Moreover, what was hung by the said colored layer description as an additive can be utilized suitably.

The second thermal transfer recording medium has heat resistance between the release layer and the metal vapor deposition layer in order to prevent damage to the base material and the release layer due to heat when the metal vapor deposition layer is deposited. An anchor layer may be provided. Moreover, you may provide the intermediate | middle layer as described in Unexamined-Japanese-Patent No. 2010-5969 between a metal vapor deposition layer and an adhesion layer.

Further, as the anchor layer, an anchor layer conventionally used in a thermal transfer recording medium provided with a metal vapor deposition layer can be used without any particular limitation. Examples of the material constituting the anchor layer include alkyd resins, phenol resins, polyimides, epoxy resins, urethane resins, unsaturated polyester resins, olefinic resins such as polyethylene and polypropylene, polymethyl methacrylate, polyacrylic amide, and the like. Acrylic resins, styrene resins such as polystyrene, vinyl resins such as polyvinyl chloride and polyvinyl acetate, polyether resins such as polyoxymethylene and polyphenylene oxide, polyvinyl butyral resins, nitrocellulose resins, ethylcellulose resins, etc. Resin. These may be used alone or in combination of two or more. From the viewpoint of ensuring heat resistance, it is preferable that the resin is crosslinked and cured with a crosslinking agent such as isocyanate. The thickness of the anchor layer is preferably in the range of 0.2 to 2.0 μm from the viewpoint of fulfilling a function as a base for metal deposition. When the thickness is less than 0.2 μm, the original function is hardly exhibited. If it is thicker than 2.0 μm, the transferability tends to be impaired.

As the metal vapor deposition layer, a metal vapor deposition layer conventionally used in a thermal transfer recording medium provided with a metal vapor deposition layer can be used without any particular limitation.

As the metal of the metal vapor deposition layer, simple substances such as amylnium, zinc, tin, nickel, chromium, titanium, copper, silver, gold, and platinum, a mixture, an alloy, and the like can be used, and aluminum and tin are preferably used. The metal vapor deposition layer can be formed by a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, an ion plating method or a chemical vapor deposition method.

The thickness of the metal vapor deposition layer is preferably 10 to 100 nm, more preferably 15 to 80 nm, from the viewpoint of obtaining a high gloss metal luster. When the thickness is less than 10 nm, visible light is not reflected to the extent that glossiness is obtained. If the thickness exceeds 100 nm, the foil breakage at the time of printing becomes worse, and the sensitivity at the time of printing is lowered.
(Third thermal transfer recording medium)

The third thermal transfer recording medium provided with the black masking layer in the present invention is a thermal transfer recording medium provided with a heat-resistant slipping layer on one side of the substrate and at least a black masking layer on the other side.

The purpose of image formation with the third thermal transfer recording medium provided with the black concealing layer in the present invention is to form a transparent image receptor, a heat-resistant slipping layer on one side of the substrate, and at least a heat-resistant peeling layer on the other side. And an image formed by thermal transfer using the first thermal transfer recording medium provided with the color material-containing adhesive layer in this order, and then a heat-resistant slipping layer on one side of the substrate and at least on the other side. Using the second thermal transfer recording medium in which the metal vapor-deposited layer and the adhesive layer are provided in this order, the surface opposite to the surface on which the transparent image-receiving surface has been transferred in a state where an image is formed by thermal transfer. This is performed for the purpose of preventing light from being transmitted through the images formed on the first and second thermal transfer recording media and weakening the metallic luster. is there.

As the black hiding layer, a conventionally known thermal transfer ink layer comprising a heat-meltable or heat-softening vehicle and a colorant can be used without any particular limitation. As the vehicle, for example, the thermoplastic resins and waxes mentioned in the color material-containing adhesive layer of the first thermal transfer recording medium may be used alone, or two or more kinds may be used in combination. . Moreover, you may use an additive suitably for a various objective.

As the colorant, a black colorant having a low light transmittance is used in order to achieve the object. Examples include black pigments and black dyes such as carbon black, titanium black, and perylene black, and blacks obtained by mixing various organic pigments and dyes. Carbon black is preferable in terms of light transmittance and cost. . The content of the colorant in the colored hiding layer is suitably 20 to 60% by weight.

The thickness of the black masking layer is preferably 0.5 to 2.5 μm. When the thickness is less than 0.5 μm, the original function is hardly exhibited. If it is thicker than 2.5 μm, the transferability tends to be impaired.

In the third thermal transfer recording medium, if necessary, a release layer may be provided between the base material and the black hiding layer, and an adhesive layer may be provided on the black hiding layer. As the release layer and the adhesive layer, a conventionally known heat-sensitive transfer ink layer made of a heat-meltable or heat-softening vehicle can be used without any particular limitation.

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

(Preparation of heat-resistant slipping layer) A material having the following formulation is kneaded to prepare a heat-resistant slipping layer coating solution, and the thickness after drying is 0.15 μm on a 4.5 μm PET film used as a substrate. The heat resistant slipping layer was prepared by coating and drying on the substrate.
Heat resistant slipping layer coating solution;
Silicone modified urethane resin 5 parts
Isocyanate (TDI) 3 parts
Solvent (MEK) 140 parts
25 parts of solvent (toluene)

(Preparation of the first thermal transfer recording medium) The composition shown in Table 1 was kneaded on the other surface of the 4.5 μm PET film substrate with the heat-resistant slip layer to prepare a heat-resistant release layer coating solution. Then, coating and drying were performed to prepare a heat-resistant release layer.

Next, a colorant-containing adhesive layer coating solution is prepared by kneading the materials of the following formulation, adjusted to a thickness after drying of 0.4 μm, and coated on the heat-resistant release layer and dried. A color material-containing adhesive layer was laminated on the heat-resistant release layer to produce a first thermal transfer recording medium.
Color material-containing adhesive layer coating solution;
Polyester resin (softening point 110 ° C.) 42 parts Polymethyl methacrylate resin (Tg 105 ° C., weight average molecular weight Mw 280,000) 42 parts
21 parts of organic pigment
Dispersant 2 parts
225 parts of solvent (MEK)

(Preparation of second thermal transfer recording medium) On the other side of the 4.5 μm PET film substrate with the heat-resistant slipping layer, a material having the following formulation was kneaded to prepare a release layer coating solution, followed by drying. After adjusting the thickness to 0.5 μm, coating and drying were performed to produce a release layer on the substrate.
Release layer coating solution;
1 part polyester resin (softening point 110 ° C)
Ketone resin (softening point 80 ° C.) 1 part acrylic resin (Tg 105 ° C., weight average molecular weight Mw 25,000)
73 parts
225 parts of solvent (MEK)

Next, an anchor layer coating solution is prepared by kneading the materials of the following formulation, adjusted to a thickness of 0.5 μm after drying, and coated on the release layer and dried to release the anchor layer. It was produced by laminating on the mold layer.
Anchor layer coating solution;
21.5 parts of nitrocellulose
Isocyanate (HDI) 16.0 parts acrylic resin (Tg 105 ° C., weight average molecular weight Mw 95,000)
5.5 parts
Solvent (MEK) 57.0 parts

Next, by vacuum deposition, aluminum was deposited on the anchor layer so as to have a deposition thickness of 20 nm, and was deposited and laminated to form a metal deposition layer.

Next, an adhesive layer coating solution is prepared by mixing materials having the following formulation, adjusted to have a thickness of 0.1 μm after drying, and coated and dried on the metal vapor-deposited layer to form an adhesive layer. A second thermal transfer recording medium was produced by laminating on the vapor deposition layer.
Adhesive layer coating solution;
Polyester resin (softening point 165 ° C) 2.0 parts
Solvent (MEK) 98.0 parts

(Preparation of third thermal transfer recording medium)) On the other side of the 4.5 μm PET film substrate with the heat-resistant slipping layer, a material having the following formulation was kneaded to prepare an adhesive layer coating solution, followed by drying. A third thermal transfer recording medium having a black masking layer was prepared by adjusting the thickness so as to be 1.5 μm later and applying and drying.
Epoxy resin (bisphenol A type, softening point 128 ° C.) 8 parts Carbon black 10 parts Polymethyl methacrylate resin (Tg 105 ° C., weight average molecular weight Mw 25,000) 8 parts
74 parts of solvent (MEK)

Evaluation of printing transferability (transfer layer cutting and substrate adhesion) Generally, when the adhesion between the substrate film and the transfer layer is insufficient or the sharpness is poor, the phenomenon of surface peeling occurs in printing. . On the other hand, if the adhesiveness between the base film and the transfer layer is too good, the sharpness and the peelability of the heating part during transfer tend to deteriorate. As an evaluation method of whether both are compatible, each thermal transfer recording medium obtained in Examples 1 to 6 was used, and a thermal transfer printer (Canon plate & sheet printer PP500 plate printing mode (transfer speed: 30 mm / sec)). ), 1 dot is printed on a 100 μm-thick PET film with optimum energy, and the print obtained on the PET film is observed with a microscope (VHX-500 manufactured by Keyence Corporation). The area ratio of printing was determined and evaluated according to the following criteria. In this case, the closer the area ratio is to 1, the better the dot reproducibility. That is, the adhesion between the base film and the transfer layer and the sharpness of the printed image at the time of transfer are compatible. If the area ratio is less than 0.9, the transfer amount is insufficient, and if it exceeds 1.10, the transfer amount is excessive, and a clear image cannot be obtained.
Evaluation criteria A: The area ratio is 0.95 to 1.05.
○: The area ratio is 0.90 to 0.94, or 1.06 to 1.10.
X: The area ratio is less than 0.90 or greater than 1.10.

(Dullness evaluation method)
An image is formed by a thermal transfer printer using the first thermal transfer recording medium of Examples 1 to 6 on a transparent glass plate having a thickness of 0.5 mm, and the second thermal transfer recording medium is superimposed on the thermal transfer printer. And transferring the third thermal transfer recording medium thereon by a thermal transfer printer, and then viewing the glass plate from the side opposite to the side where the transfer was performed. The dull state was judged visually. The judgment criteria are shown below.
A: The metallic luster is not dull.
○: The metallic luster is slightly dull, but there is no practical problem.
X: The metallic luster is dull and there is a practical problem.
Printer used: Canon plate & sheet printer PP500 Plate printing mode (printing speed: 30 mm / sec)

Table 1 shows the results of evaluation of print transferability (transfer layer cutting property and substrate adhesion) and dullness evaluation of each example.

Claims (4)

Mainly composed of a heat-resistant slipping layer on one surface of the substrate and at least fibrous or needle-like alumina hydrate particles or alumina particles defined by an aspect ratio (major axis / minor axis) of 30 to 5000 on the other surface A thermal transfer recording medium comprising a heat-resistant release layer and a colorant-containing adhesive layer as components in this order. The thermal transfer recording medium according to claim 1, wherein the alumina hydrate particles or alumina particles have a minor axis of 1 to 10 nm and a major axis of 100 to 10,000 nm. 2. The heat-resistant release layer of the thermal transfer recording medium comprises the alumina hydrate particles or alumina particles and a resin, and the alumina hydrate particles or alumina particles are 60% by weight or more. Alternatively, the thermal transfer recording medium according to claim 2. The thermal transfer recording medium according to any one of claims 1 to 3, wherein the heat-resistant release layer of the thermal transfer recording medium has a thickness of 0.1 µm to 0.6 µm.