JP7652325B2 - Prints - Google Patents

Description

This disclosure relates to a method for producing a printed matter and the printed matter.

Prints are known in which an image is formed on one side of a transparent substrate and a protective layer is transferred onto the image. In addition, to improve design, a white layer (white concealing layer) may be formed on the transparent substrate or image before the protective layer is transferred.

The white layer has low adhesion to the transparent substrate, so in order to firmly adhere the white layer to the transparent substrate, high thermal energy was applied when transferring the protective layer. However, applying high energy caused the surface of the protective layer to become matte with fine irregularities, increasing the haze value and impairing the transparency of the printed matter.

Patent No. 6672680 International Publication No. 2017/159805

The objective of the present disclosure is to provide a method for producing a printed matter and a printed matter that suppresses deterioration of the transparency of the printed matter while firmly adhering a white layer to a transparent substrate.

The method for producing a printed matter disclosed herein includes the steps of heating a thermal transfer sheet having a white layer and a protective layer arranged in surface order on a substrate, and transferring the white layer to a portion of an image forming surface of a transferee having a transparent substrate with an image formed on one side thereof, and heating the thermal transfer sheet and transferring the protective layer to the transferee so as to cover the white layer, and the transfer energy of the protective layer in the area where the white layer is formed is made higher than the transfer energy of the protective layer in the area where the white layer is not formed.

The print of the present disclosure comprises a transparent substrate having an image formed on one side thereof, a white layer provided on the one side of the transparent substrate so as to cover at least a portion of the image, and a protective layer provided on the one side of the transparent substrate so as to cover the white layer, and the area where the white layer is provided has a haze value of 50% or more, and at least a portion of the area where the white layer is not provided has a haze value of 15% or less.

According to the present disclosure, it is possible to prevent deterioration of the transparency of the printed matter while firmly adhering the white layer to the transparent substrate.

FIG. 2 is a cross-sectional view of a thermal transfer sheet according to an embodiment of the present disclosure. 2a and 2b are cross-sectional views of a transfer target. 3a and 3b are cross-sectional views illustrating steps in a method for producing a print. 4a and 4b are cross-sectional views illustrating the steps of a method for producing a print. 5a and 5b are cross-sectional views illustrating steps in a method for producing a print. FIG. 7a is a plan view of the transferred object, and FIG. 7b is a cross-sectional view taken along line VIIb-VIIb in FIG. 7a. FIG. FIG. FIG. FIG. 13 is a diagram showing an example of division of an area in which protective layer transfer energy is changed.

The following describes the embodiments with reference to the drawings. Note that in the drawings, the width, thickness, etc. of each part may be shown diagrammatically compared to the actual embodiment in order to make the description clearer, but this is merely an example and does not limit the interpretation of the present disclosure. In addition, in this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals, and detailed descriptions may be omitted as appropriate.

Figure 1 is a cross-sectional view of a thermal transfer sheet according to an embodiment of the present disclosure. As shown in Figure 1, the thermal transfer sheet 10 has a color material layer 3, a white layer 5, and a protective layer 7 provided in surface order on one surface of a substrate 1. A back layer 9 is provided on the other surface of the substrate 1.

The color material layer 3 has a yellow color material layer 3Y containing a yellow color material, a magenta color material layer 3M containing a magenta color material, and a cyan color material layer 3C containing a cyan color material, which are arranged in surface sequence. The color materials contained in the yellow color material layer 3Y, the magenta color material layer 3M, and the cyan color material layer 3Y are, for example, sublimation dyes. The color material layer 3 may have a heat-meltable ink layer instead of or in addition to the dye layer.

A release layer may be provided between the protective layer 7 and the substrate 1. Also, an adhesive layer may be provided on the protective layer 7.

When the assembly consisting of "five panels" of the yellow color material layer 3Y, the magenta color material layer 3M, the cyan color material layer 3C, the white layer 5, and the protective layer 7 is defined as "one unit," this "one unit" is repeatedly provided on one side of the substrate 1 of the thermal transfer sheet 10.

Next, each component of the thermal transfer sheet 10 will be described.

(Substrate)
The substrate 1 is not limited in any way, and any substrate known in the field of thermal transfer sheets can be appropriately selected and used. Examples include stretched or unstretched plastic films such as highly heat-resistant polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, or polyether sulfone, polypropylene, polycarbonate, cellulose acetate, polyethylene derivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, or ionomers. Composite films in which two or more of these materials are laminated can also be used.

The substrate 1 may be subjected to adhesion-improving treatments such as corona discharge treatment, plasma treatment, ozone treatment, frame treatment, primer (also called anchor coat, adhesion promoter, or easy adhesive) coating treatment, preheating treatment, dust removal treatment, vapor deposition treatment, alkali treatment, and application of an antistatic layer. The substrate 1 may also contain additives such as fillers, plasticizers, colorants, and antistatic agents as necessary. There are no particular limitations on the thickness of the substrate 1, but a range of 2 μm to 10 μm is preferred.

(Colorant Layer)
The color material layer 3 contains a color material and a binder resin. Examples of the color material contained in the color material layer 3 include a diarylmethane dye, a triarylmethane dye, a thiazole dye, a merocyanine dye, a pyrazolone dye, a methine dye, an indoaniline dye, a pyrazolomethine dye, an azomethine dye such as acetophenoneazomethine, pyrazoloazomethine, imidazoleazomethine, imidazoazomethine, and pyridoneazomethine, a xanthene dye, an oxazine dye, and a cyanosulfonyl dye such as dicyanostyrene and tricyanostyrene. Examples of the dyes include azo dyes such as ethylene dyes, thiazine dyes, azine dyes, acridine dyes, benzene azo dyes, pyridone azo, thiophene azo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo, and disazo, spiropyran dyes, indolinospiropyran dyes, fluoran dyes, rhodamine lactam dyes, naphthoquinone dyes, anthraquinone dyes, and quinophthalone dyes. The colorant layer 3 may contain one type of colorant alone or two or more types.

There are no particular limitations on the binder resin contained in the color material layer 3, and any resin that has a certain degree of heat resistance and a suitable affinity with the sublimable dye can be appropriately selected and used. Examples of such binder resins include cellulose resins such as nitrocellulose, cellulose acetate butyrate, and cellulose acetate propionate, vinyl resins such as polyvinyl acetate and polyvinyl acetal, acrylic resins such as poly(meth)acrylate and poly(meth)acrylamide, polyurethane, polyamide, and polyester.

The color material layer 3 may contain additives such as inorganic particles and organic particles. Examples of inorganic particles include talc, carbon black, aluminum, and molybdenum disulfide, and examples of organic particles include polyethylene wax and silicone resin particles. The color material layer 3 may contain a release agent. Examples of the release agent include modified or unmodified silicone oil (including those known as silicone resins), phosphate esters, and fatty acid esters.

There is no particular limitation on the method for forming the color material layer 3. The color material layer can be formed by preparing a coating liquid for the color material layer by dissolving or dispersing the binder resin, color material, and additives and release agents added as necessary in an appropriate solvent, and then applying and drying this coating liquid onto the substrate 1 or any layer provided on the substrate 1. The thickness of the color material layer 3 is generally 0.2 μm or more and 2.0 μm or less.

(White layer)
As described below, the white layer 5 has a function as a concealing layer that conceals an image. The white layer 5 contains a white pigment and a resin material. Examples of the white pigment include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, and calcium carbonate. Among these, titanium oxide is preferred from the viewpoint of whiteness.

The content of the white pigment in the white layer 5 is preferably 50% by mass or more and less than 90% by mass, and more preferably 75% by mass or more and less than 90% by mass. This can further improve the whiteness of the image.

Examples of resin materials include polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, imide resin, cellulose resin, styrene resin, polyol resin, polycarbonate, and ionomer resin. The white layer can contain two or more of these resin materials. Among these, the white layer preferably contains at least one of (meth)acrylic resin and polyol resin as the main resin material. This can improve the dispersion stability of the white pigment in the coating liquid for forming the white layer. The main resin material refers to a resin material that occupies 70 parts by mass or more per 100 parts by mass of the total amount of resin materials contained in the white layer.

The content of the resin material in the white layer 5 is preferably 10% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 25% by mass or less. This suppresses re-aggregation of the white pigment and provides high hiding power.

The white layer 5 may contain additives such as fillers, plasticizers, antistatic materials, UV absorbers, inorganic particles, organic particles, release agents, and dispersants.

The thickness of the white layer 5 is 0.5 μm or more and 4.5 μm or less. This improves the whiteness of the image formed and also improves the transferability of the protective layer onto the white layer 5. From the viewpoint of the whiteness of the image and the transferability of the protective layer, the thickness of the white layer 5 is preferably 1 μm or more and 4.3 μm or less, and more preferably 2 μm or more and 4 μm or less.

The white layer 5 can be formed by dispersing or dissolving the above-mentioned materials in water or a suitable solvent, applying the resulting coating to the substrate 1 by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, or rod coating to form a coating film, and then drying the coating film.

(Protective Layer)
Examples of the binder resin constituting the protective layer 7 include polyester, polyester urethane resin, polycarbonate, acrylic resin, epoxy resin, acrylic urethane resin, silicone-modified resins of these resins, and mixtures of these resins. The protective layer 7 may contain an ultraviolet absorbing resin or an actinic ray curable resin. The actinic ray curable resin means a resin cured by irradiating an actinic ray with an actinic ray. The actinic ray means a ray that acts chemically on the actinic ray curable resin to promote polymerization, and specifically means visible light, ultraviolet light, X-rays, electron beams, α rays, β rays, γ rays, and the like.

There is no particular limit to the content of the binder resin constituting the protective layer 7, but the binder resin is preferably 20% by mass or more, and more preferably 30% by mass or more, relative to the total solid content of the protective layer 7. There is no particular limit to the upper limit of the binder resin content, which is 100% by mass. In addition to the binder resin, the protective layer 7 may contain other materials such as various fillers, fluorescent whitening agents, and ultraviolet absorbing agents to improve weather resistance.

There is no particular limitation on the method for forming the protective layer 7. The above-mentioned binder resin and additives, which are added as necessary, are dissolved or dispersed in an appropriate solvent to prepare a coating liquid for the protective layer, and the coating liquid is applied and dried onto the substrate 1 or any layer provided on the substrate 1 to form the protective layer. There is no particular limitation on the thickness of the protective layer 7, but it is usually 0.5 μm or more and 10 μm or less.

To improve the transferability of the protective layer 7, a release layer can be provided between the substrate 1 and the protective layer 7. The release layer contains one or more resin materials. Examples of the resin material include vinyl resins such as ethylene-vinyl acetate copolymer and vinyl chloride-vinyl acetate copolymer, (meth)acrylic resins, cellulose resins, and polyesters.

To improve adhesion between the transfer object and the protective layer 7, an adhesive layer may be provided on the protective layer 7. The adhesive layer contains a thermoplastic resin that softens when heated and exhibits adhesion. Examples of thermoplastic resins include vinyl resins such as vinyl chloride, vinyl acetate, and vinyl chloride-vinyl acetate copolymers, polyester, (meth)acrylic resin, polyurethane, cellulose resin, melamine resin, polyamide, polyolefin, and styrene resin.

(Back layer)
There is no limitation on the material of the back layer 9, and examples thereof include cellulose resins such as cellulose acetate butyrate and cellulose acetate propionate, vinyl resins such as polyvinyl acetal, acrylic resins such as polymethyl methacrylate, polyethyl acrylate, polyacrylamide and acrylonitrile-styrene copolymers, natural or synthetic resins such as polyamide resins, polyamideimide, polyester, polyurethane, silicone-modified or fluorine-modified urethane, etc. The back layer 9 may contain one type of these resins alone, or may contain two or more types.

The back layer 9 may contain a solid or liquid lubricant. Examples of lubricants include various waxes such as polyethylene wax, higher aliphatic alcohols, organopolysiloxanes, anionic surfactants, cationic surfactants, nonionic surfactants, fluorosurfactants, organic carboxylic acids and their derivatives, metal soaps, fluororesins, silicone resins, talc, particles of inorganic compounds such as silica, etc. The content of the lubricant in the back layer is generally 5% by mass or more and 50% by mass or less, and preferably 10% by mass or more and 40% by mass or less.

There is no particular limitation on the method for forming the back layer, and the back layer can be formed by preparing a coating liquid for the back layer by dissolving or dispersing the resin and, if necessary, a lubricant in an appropriate solvent, and then applying and drying this coating liquid onto the substrate 1. The thickness of the back layer is preferably 0.5 μm or more and 10 μm or less.

As shown in FIG. 2a, the transfer target 20 has a transparent substrate 21 and a receiving layer 23 provided on one surface of the transparent substrate 21. In this embodiment, a configuration in which the receiving layer 23 is provided on the transparent substrate 21 is described, but if the material of the transparent substrate 21 itself is capable of receiving the dye, the receiving layer 23 can be omitted.

The transparent substrate 21 has optical transparency that allows an image formed on one side to be visible from the other side, and preferably has a haze value of 15% or less. Examples of materials for the transparent substrate 21 include polyvinyl chloride, polyethylene terephthalate, polycarbonate, acrylic resin, cycloolefin, polyester, polystyrene, and acrylic styrene.

The thickness of the transparent substrate 21 is preferably 200 μm or more and 800 μm or less.

(Receptive layer)
The receiving layer 23 is a layer that receives the color material (sublimation dye) that migrates from the color material layer 3 of the thermal transfer sheet 10 and maintains the formed image.

The receiving layer 23 contains a resin material. The resin material is not limited as long as it is a resin that is easily dyed with a dye, and examples thereof include olefin resin, vinyl resin, (meth)acrylic resin, cellulose resin, ester resin, amide resin, carbonate resin, styrene resin, urethane resin, and ionomer resin. The receiving layer 23 can contain two or more of the above resin materials.

The content of the above resin material in the receiving layer 23 is preferably 80% by mass or more and 98% by mass or less, and more preferably 90% by mass or more and 98% by mass or less.

In one embodiment, the receiving layer 23 contains a release agent. This can improve the releasability from the thermal transfer sheet 10. Examples of the release agent include solid waxes such as polyethylene wax, amide wax, and Teflon (registered trademark) powder, fluorine-based or phosphate-based surfactants, silicone oil, reactive silicone oil, cured silicone oil, and various modified silicone oils, and various silicone resins. As the silicone oil, modified silicone oil is preferable. As the modified silicone oil, amino-modified silicone, epoxy-modified silicone, aralkyl-modified silicone, epoxy-aralkyl-modified silicone, alcohol-modified silicone, vinyl-modified silicone, urethane-modified silicone, and the like can be preferably used, with epoxy-modified silicone, aralkyl-modified silicone, and epoxy-aralkyl-modified silicone being particularly preferable. The receiving layer 23 can contain two or more of the above release agents.

The content of the release agent in the receiving layer 23 is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 0.5% by mass or more and 10% by mass or less. This allows the transparency of the receiving layer 23 to be maintained while improving the releasability from the thermal transfer sheet 10.

The thickness of the receiving layer 23 is preferably 0.5 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less. This improves the density of the image formed on the receiving layer 23.

The receiving layer 23 can be formed by dispersing or dissolving the above-mentioned materials in a suitable solvent to prepare a coating liquid, applying this to the transparent substrate 21 by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating to form a coating film, and then drying the coating film.

The receiving layer 23 may be provided on the entire surface of the transparent substrate 21 as shown in FIG. 2a, or may be provided on a portion (partial) of the surface as shown in FIG. 2b. In the configuration shown in FIG. 2b, for example, the receiving layer 23 is provided only in the area where an image is to be formed. In the area where the receiving layer 23 is not provided, the surface of the transparent substrate 21 is exposed.

Next, a method for producing a print will be described with reference to Figures 3 to 5. Figures 3a, 4a, and 5a show an example of producing a print using the transferee 20 shown in Figure 2a. Figures 3b, 4b, and 5b show an example of producing a print using the transferee 20 shown in Figure 2b.

First, the thermal transfer sheet 10 and the recipient 20 are prepared. Next, the thermal transfer sheet 10 and the recipient 20 are superimposed so that the colorant layer 3 and the receiving layer 23 face each other, and the thermal transfer sheet 10 is heated from the back layer 9 side using a thermal head of a thermal transfer printer or the like to thermally transfer the colorant contained in the colorant layer 3, forming images G1 and G2 on the receiving layer 23 as shown in Figures 3a and 3b. If the receiving layer 23 is omitted, the images G1 and G2 are formed on the surface of the transparent substrate 21.

Following the image formation process, a white layer transfer process is performed. In the white layer transfer process, the thermal transfer sheet 10 and the transferee 20 are superimposed so that the white layer 5 and the receiving layer 23 (the image forming surface of the transferee 20) face each other, and the thermal transfer sheet 10 is heated from the back layer 9 side with a thermal head, and the white layer 5 is transferred to the desired area.

In the example shown in Figures 4a and 4b, the white layer 5 is transferred so as to cover the image G2 and its vicinity. The white layer 5 is not transferred onto the image G1. In the example shown in Figure 4b, a portion of the white layer 5 is transferred onto the image G2, and the other portion is transferred onto the transparent substrate 21.

Next, the protective layer 7 is transferred so as to cover at least the white layer 5, and a print is produced. In the example shown in Figures 5a and 5b, the protective layer 7 is transferred to the entire surface of the transfer target 20 to produce the print 30. In the configuration shown in Figure 5b, the protective layer 7 includes a portion transferred onto the white layer 5, a portion transferred onto the receiving layer 23, and a portion transferred onto the transparent substrate 21.

In the protective layer transfer process, the thermal transfer sheet 10 and the transferee 20 are superimposed so that the protective layer 7 and the receiving layer 23 face each other, and the thermal transfer sheet 10 is heated from the back layer 9 side with a thermal head. At this time, the transfer energy E1 (energy applied by the thermal head) of the protective layer 7 in the white layer forming region R1 is made higher than the transfer energy E2 of the protective layer 7 in the other region (white layer non-forming region) R2. The transfer energy E1 is preferably 1.2 to 4.0 times the transfer energy E2, and more preferably 1.5 times or more.

Figure 6 shows the produced print 30 viewed from the front side (transparent substrate 21 side) and from the back side (protective layer 7 side). When print 30 is viewed from the front side, images G1 and G2 can be seen through transparent substrate 21. On the other hand, when print 30 is viewed from the back side, image G1 can be seen, but image G2 is hidden by white layer 5 and is difficult to see.

Since high thermal energy is applied to the white layer 5 during the transfer of the protective layer, the white layer 5 can be firmly attached to the transparent substrate 21 and the receiving layer 23. In the white layer forming region R1, the application of high thermal energy causes the surface of the protective layer 7 to become matte and the haze value to increase, but since this is the region where the white layer 5 is provided, this does not affect the transparency of the printed matter 30.

In the white layer non-forming region R2, the thermal energy during the transfer of the protective layer is low, which prevents the surface of the protective layer 7 from becoming matte, and thus prevents the transparency of the printed matter 30 from deteriorating.

The haze value in the areas of the printed matter 30 where the white layer 5 and images G1 and G2 are not formed is preferably 15% or less, and more preferably 10% or less. The haze value can be measured by a method conforming to JIS K7136:2000, for example, using a haze meter HM150N manufactured by Murakami Color Research Laboratory.

The haze value in the area of the printed matter 30 where the white layer 5 is formed is preferably 50% or more, and more preferably 70% or more. The haze value can be measured by the method described above.

As shown in Figures 7a and 7b, a print may be produced using a transferee 20A on which a frame-shaped colored layer 40 containing a metallic pigment or a pearl pigment is formed by a known printing method such as offset printing on the periphery of the other surface of the transparent substrate 21 (the surface opposite to the surface on which the receiving layer 23 is provided). Figure 8 is a cross-sectional view of a print 30A using the transferee 20A, and Figure 9 is a plan view of the print 30A.

As shown in FIG. 10, a two-dimensional code or the like may be formed by transferring a heat-meltable ink or the like onto the white layer 5. When the printed matter 30 is viewed from the front side, the two-dimensional code Q is concealed by the white layer 5, but when viewed from the back side, the two-dimensional code Q is visible.

When the colored layer 40 is formed as shown in FIG. 9, the two-dimensional code Q may be formed on the back side of the colored layer 40, sandwiching the transparent substrate 21. In this case, too, when the printed matter 30A is viewed from the front side, the two-dimensional code Q is concealed by the colored layer 40.

In the above embodiment, an example was described in which the transfer energy E1 of the protective layer 7 in the white layer-forming region R1 is made higher than the transfer energy E2 of the protective layer 7 in the white layer non-forming region R2. However, as shown in FIG. 11, the transfer energy E11 in the peripheral portion R11 of the white layer-forming region R1 may be made higher than the transfer energy E12 in the central portion R12 of the white layer-forming region R1 (E11>E12>E2). It is preferable that the transfer energy E11 be approximately 1 to 2 times the transfer energy E12.

The width of the peripheral portion R11 is, for example, about 5 dots. The dots depend on the printing density of the heating elements in the thermal head.

In the above embodiment, a thermal transfer sheet was described in which five panels, a yellow color material layer 3Y, a magenta color material layer 3M, a cyan color material layer 3C, a white layer 5, and a protective layer 7, are arranged in face sequence, but at least one panel may be a separate thermal transfer sheet, or each panel may be a separate thermal transfer sheet.

In the above embodiment, the receiving layer 23 may be omitted, and a color material may be transferred directly onto the transparent substrate 21 to form an image, or a white layer 5 may be transferred onto the transparent substrate 21.

Reference Signs List 1: Substrate 3: Colorant layer 5: White layer 7: Protective layer 9: Back layer 10: Thermal transfer sheet 20: Transfer recipient 21: Transparent substrate 23: Receptive layer

Claims (2)

A transparent substrate having an image formed on one surface thereof;
a white layer provided on the one surface of the transparent base material so as to cover at least a portion of the image;
a protective layer provided on the one surface of the transparent base material so as to cover the white layer;
Equipped with
The haze value in the region where the white layer is provided is 50% or more,
A printed matter, wherein at least a part of an area where the white layer is not provided has a haze value of 15% or less. A transparent substrate;
a receiving layer provided on at least a part of one surface of the transparent substrate and having an image formed thereon;
a white layer disposed on at least a portion of the receiving layer;
a protective layer provided on the one surface side of the transparent base material so as to cover the white layer;
Equipped with
The haze value in the region where the white layer is provided is 50% or more,
A printed matter, wherein at least a part of an area where the white layer is not provided has a haze value of 15% or less.

Images