JPH10264495A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recording sheet useful for discussion of package design, and the like, in which an ordinary image can be recorded on the surface of a transparent basic material and a white image can be formed on the rear surface. SOLUTION: An ink jet ink, sublimation transfer ink and thermal fusion transfer ink receiving layer 1 is formed on the surface of a transparent basic material 2 and a white porous layer 3 being rendered transparent by heating is formed on the rear surface. Since an ordinary full color image 4 can be recorded on the surface side and an arbitrary while image can be formed of transparent ink on the rear surface by means of a thermal transfer printer, or the like, a special print effect can be achieved where a white print is made on a transparent basic material by general printing and a color print is made thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An object of the present invention is to provide a recording sheet having both a full-color image and a white image forming section used for studying package design in a packaging industry or a design planning department. In particular, the present invention relates to a recording sheet having an ink receiving layer on the front surface side of which an image is formed by an ink-jet printer, a heat-sensitive sublimation transfer printer, and a heat-sensitive melt transfer printer, and a white porous layer provided on the back surface with transparency by heating.

[0002]

2. Description of the Related Art Conventionally, when proofreading layouts, images, colors, and the like of packaging designs, etc., test printing and the like have been performed by an actual printing machine after a plate making process, but with the development of media capable of outputting full color, Recently, various types of media have been used for the test print to reduce the cost and time of plate making and printing. However, since there is no transparent recording sheet that can output a full-color image and a white image portion together, in the field of a soft packaging material and the like where it is usual to perform white underprinting on a transparent film, these are used. The use of media was also limited.

[0003] Output means of a full-color image include a wire dot recording system, a thermosensitive coloring recording system, a heat-sensitive melt transfer recording system, a thermosensitive sublimation transfer recording system, an electrophotographic recording system,
Various systems such as an ink jet recording system have been put to practical use. Among them, the ink jet recording system has excellent features such as low printing cost, inexpensive and compact apparatus, capable of high-speed recording without noise, adaptable to large size, and high resolution. For this reason, attention has been paid to the use as a printer for quickly and accurately outputting image information such as characters and figures produced by a computer or the like. Further, since colorization is easy and the pattern is clear, there is an increasing demand for recording image information produced by a computer on a transparent recording sheet by an ink jet printer and using this as a proofreading document. On the other hand, thermal sublimation transfer recording, which can form a clear image equivalent to a silver halide photograph with a wide range of gradations, is also highly evaluated particularly for use in forming high-quality full-color images. Further, heat-sensitive fusion transfer recording, which can form a high-density image, is also used for certain applications because of its excellent preservability.

[0004]

As a white image forming means, there are various transfer recording methods, but a method using a white porous base material which is made transparent by heating is an easy and inexpensive means for forming a white image. Attention has been paid. But,
A recording sheet capable of recording a full-color image and a white image at the same time has not been realized in spite of a need in the past, but it has not been realized. Therefore, the present invention integrates a full-color image utilizing excellent characteristics such as an ink jet recording method and a sublimation transfer recording method with a white image formed by a porous base material which is made transparent by heating in order to satisfy the requirements of these packaging designs and the like. It is intended to realize a recording sheet that can be recorded by using a recording medium.

[0005]

According to a first aspect of the present invention, there is provided an ink receiving layer provided on one surface of a transparent substrate, and the other surface of the substrate is transparent by heating. A recording sheet provided with a white porous layer to be formed. Since such a recording sheet is used, image recording such as a full-color image and a printed matter having a white image can be easily obtained on one recording sheet.

According to a second aspect of the present invention, there is provided a recording sheet according to the first aspect, wherein the ink receiving layer comprises an ink jet ink receiving layer;
The image is formed by an inkjet printer,
The white porous layer is made transparent by a thermal transfer printer. Since such a recording sheet is used, printed matter having an image such as a full-color image and a white image on a single recording sheet can be easily obtained by an ink jet printer and a thermal transfer printer.

According to a third aspect of the present invention, there is provided a recording sheet according to the first aspect, wherein the ink receiving layer comprises a sublimation transfer ink receiving layer, and the image is formed by a sublimation transfer printer. It is characterized in that the white porous layer is made transparent by a thermal transfer printer. Because of such a recording sheet, a printed matter having an image recording such as a full-color image and a white image on one recording sheet can be easily obtained by a sublimation transfer printer and a thermal transfer printer.

According to a fourth aspect of the present invention, there is provided a recording sheet according to the first aspect, wherein the ink-receiving layer comprises a heat-melt transfer ink-receiving layer, and image formation is performed by the heat-melt transfer. The method is characterized in that the white porous layer is made transparent by a thermal transfer printer. Because of such a recording sheet, a printed matter having an image recording such as a full-color image and a white image on one recording sheet can be easily obtained by a thermal transfer printer.

According to a fifth aspect of the present invention, there is provided a recording sheet according to the second aspect, wherein the ink receiving layer is an ink jet ink receiving layer containing an aqueous resin as a main component. And According to a sixth aspect of the present invention, in the recording sheet according to the second aspect, the ink receiving layer is an inkjet ink receiving layer formed of a transparent porous layer. Because of such a recording sheet, good recording of the inkjet ink is performed.

[0010] The invention according to claim 7 of the present invention for solving the above problems is a recording sheet used by being superimposed on a sheet on which an image is recorded on a transparent base material, wherein at least the transparent base material is used. A recording sheet characterized in that a white porous layer which is made transparent by heating is provided on one surface. Since such a recording sheet, a separate recording sheet on which an image such as a full-color image has been recorded, and a recording sheet having a white image in which the white porous layer has been made transparent by a thermal transfer printer are superimposed. A recorded image such as a full-color image can be easily examined.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a recording sheet of the present invention. In FIG. 1, the recording sheet of the present invention includes a substrate 2, an image-receiving ink-receiving layer 1 formed on one surface of the substrate 2, and a surface of the substrate 2 opposite to the ink-receiving layer. It has a white porous layer 3 which becomes transparent by heating. An anti-curl / anti-static layer 6 for preventing curl and anti-static is provided between the substrate and the white porous layer, if necessary. At the time of recording on the recording sheet, the ink receiving layer 1 functions as an image receiving sheet by ink jet recording or the like, and the white porous layer 3 functions to form a white image by heating. The curl prevention / antistatic layer has an effect of preventing curling and charging of the base material by ink jet recording or the like.

Various types of image receiving layers can be formed on the ink receiving layer 1. For example, when the ink-receiving layer is an ink-receiving layer mainly composed of a water-soluble resin or a water-absorbing resin, an image can be formed with an ink-jet printer, and the ink-receiving layer is a salt that receives a sublimable dye. In the case of a sublimation transfer ink receiving layer such as a vinyl acetate resin, an image can be formed by a printer using a sublimation transfer ribbon, and in the case where the ink receiving layer is a hot melt transfer ink receiving layer, the hot melt transfer ink is used. An image can be formed by a printer using a ribbon.

FIG. 2 is a view showing a state in which an image is formed on the recording sheet of the present invention. As shown in FIG. 2, an image 4 is formed on the ink receiving layer 1 by ink jet recording, sublimation transfer recording, hot melt transfer recording, or the like. The white porous layer 3 of the substrate 2 is heated by a thermal transfer printer and has a transparent part 5 which is partially transparent. Therefore, a portion that is not made transparent forms a white image. The transparency can be formed so as to overlap with the image, can be formed around the image, or can be formed independently of the image. This makes it possible to express the relationship between the underprinting white ink on the transparent film in normal gravure printing or the like and the image thereon. When the transparency is performed by a thermal transfer printer, the transparency can be obtained by heating directly with a thermal head of the thermal transfer printer or through a transparent film without using an ink ribbon.

FIG. 3 is a view for explaining the usage of the recording sheet according to the seventh aspect of the present invention. As shown in the figure, in the case of the recording sheet, another recording sheet (A1) on which an image of full color or the like is recorded and the recording sheet (B) of the present invention are used.
1) is prepared. In the next recording stage, the image 4 is recorded on the recording sheet (A1) and the recorded sheet (A2)
Becomes The transparent part 5 is formed on the recording sheet (B1) to become a recorded sheet (B2). In the next superposition stage, the recorded sheet (A2) and the recorded sheet (B2) are superimposed or used as a recorded sheet (C) integrated by the temporary bonding portion 7.

As the recording sheet (A1), any recording material formed on a transparent substrate can be used without particular limitation. For example, a recording sheet having the above-described inkjet ink receiving layer, a recording sheet having the sublimation transfer ink receiving layer, a recording sheet having the hot melt transfer ink receiving layer, or the like. Also,
The recording sheet (B1) is made of a transparent base material provided with a white porous layer that becomes transparent by heating, and forms a white image by heating the white porous layer with a thermal head or the like. is there. Normally, a white image is used for an application that requires alignment with an image recorded on the recording sheet (A1), but also includes an application that does not require alignment at all. For example, there is a case where a white copy-forgery-inhibited pattern or a line pattern is arranged on the entire back surface of the image of the recorded sheet (A2) on which full-color image recording or the like has been performed.
When it is necessary to align the images of the recorded sheet (A2) and the recorded sheet (B2), appropriate alignment means, for example, providing a registration mark or the like on both images or aligning pins with both recording devices The recording sheet is provided with a pin hole and recorded, and the position is adjusted by the pin.

The recorded sheet (A2) and the recorded sheet (B
2), the printed record of the recorded sheet (A2) and the printed record of the recorded sheet (B2) are obtained by recording the recorded sheet (A2) on the surface and the recorded sheet (B2) on the inner side. May be recorded and superimposed, or the images of the recorded sheet (A2) and the recorded sheet (B2) may be formed in a mirror image relationship and superimposed so that both are inside (FIG. 3 (C) shows this case). In this case, it is necessary to perform image recording so that the recording sheet (A) is backprinted, but there is an advantage that both images are protected by the base material and are not damaged by abrasion or the like. Further, it is of course possible to record both the printed sheet (A2) and the printed sheet (B2) as back printing, and make the white image of the printed sheet (B2) the outermost surface. The white porous layer which is made transparent by heating the recording sheet (B1) can be provided not only on one side of the substrate but also on both sides of the substrate. In this case, there is an advantage that the concealment of the white image can be enhanced.

The recorded sheet (A2) and the recorded sheet (B
The superposition or lamination of 2) can be performed by any method. When they are simply used by being overlapped, they may be overlapped by being aligned with the pin holes as described above, or may be overlapped by being aligned with the register marks. When laminating using an adhesive, a pressure-sensitive adhesive or the like in a state of being superimposed, a heat-sensitive or pressure-sensitive adhesive or pressure-sensitive adhesive can be used.
When permanent storage is not desired, it can be said that the case of a re-adhesive pressure-sensitive adhesive that can be used by re-peeling can be reused and is more suitable for the purpose of the recording sheet of the present invention. .

Hereinafter, the configuration of each part of the recording sheet of the present invention will be sequentially described. (Substrate) As the transparent substrate 2 used in the recording sheet of the present invention, the same substrate as that used in the conventional recording sheet can be used as it is. Many of the recording sheets of the present invention are used as imitating a transparent film for packaging, and thus require transparency. Further, when an image is formed on the ink receiving layer by heat-sensitive sublimation transfer or heat-sensitive fusion transfer, heat resistance is also required. In addition, a thermoplastic resin having dimensional stability and rigidity is preferable. Specifically, a thickness of about 5 to 250 μm of polyethylene terephthalate resin, polycarbonate resin, acrylic resin, polyvinyl chloride resin, polypropylene resin, polystyrene resin, polyvinyl alcohol resin, polyethylene resin, diacetate resin, triacetate resin, polyimide resin, etc. Preferably, a film or sheet having a thickness of about 50 to 180 μm is used.
When the transparent substrate 2 has insufficient adhesion to the ink receiving layer formed on its surface, it is preferable to apply a primer treatment or a corona discharge treatment to its surface. Further, an anti-curl / antistatic layer 6 may be provided on the back surface of the substrate 2 where the ink receiving layer is not formed, between the substrate and the white porous layer.

(Ink receiving layer) As the ink receiving layer of the recording sheet of the present invention, an ink receiving layer for ink jet recording, an ink receiving layer for sublimation transfer recording,
Three types of ink-receiving layers for hot-melt transfer recording are possible. Hereinafter, each of these ink receiving layers will be described sequentially.

Ink-jet ink receiving layer The ink-jet ink receiving layer is mainly characterized by a mixture of an aqueous water-absorbing resin, a water-soluble resin, and a water-soluble resin having wet heat resistance and low-temperature printability. It is particularly preferable that the mixture is a combination of a water-absorbing polyester resin, polyvinyl alcohol, and polyvinyl pyrrolidone. Aqueous water-absorbent resin is a water-soluble resin that is cross-linked to make it water-absorbent and water-insoluble, and is obtained by coating a water-soluble resin partially cross-linked or grafted. After coating, there is a cross-linking agent or a cross-linked by heating or ionizing radiation. Other examples include copolymers of a hydrophilic monomer and a hydrophobic monomer, such as a water-absorbing alkyd resin, a polyester resin, a polyvinyl acetate resin, a polyvinyl chloride copolymer resin, an NBR resin, and an SB resin.
R resin, polyurethane resin, acrylic resin, polyamide resin and the like are used alone or as a mixture, copolymer or modified product. The modified product is, for example, a product obtained by copolymerizing or grafting a monomer or oligomer containing a hydroxyl group, a carboxylic acid, a sulfonic acid, a quaternary ammonium salt, or the like to increase the hydrophilicity. Above all, the water-absorbing polyester resin is particularly preferable because it has high adhesiveness to the substrate, high film strength, and scars of the print roller marks on the printed portion during transport of the printer, that is, high wet strength.

The water-soluble resin is soluble in water or a mixed solvent of water and alcohol, and various known resins can be used. For example, polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylic acid, cellulose resins (carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polyvinyl acetal resins, polyvinyl methyl ether, polyamine And at least one of water-soluble resins such as polyethyleneimine, casein, gelatin, and starch, and / or copolymers thereof, and cation / anion-modified products. Among them, polyvinyl alcohol is particularly preferable because it has excellent ink absorbency, color developability, wet strength, and appropriate solution viscosity.

The water-soluble resin having wet heat resistance and low-temperature printability is a resin that is soluble in water, alcohol or a mixed solvent thereof, and is used in various environments (temperature range: -20 to 50 ° C., humidity range: 10 to 10). (90% RH) is preferable. In particular, those which hardly deteriorate in water absorbency and printability before and after storage under high temperature and high humidity. In addition, those having good printability in each environment, particularly those having almost no decrease in water absorbency and printability in a low temperature environment, and various conventionally known ones are used. For example, polyvinylpyrrolidone, poly (meth) acrylic acid, cellulosic resins (methylcellulose, hydroxypropylmethylcellulose,
Water-soluble resins such as hydroxypropylethylcellulose), polyethylene oxide and polyethylene glycol and / or copolymers thereof, specifically, at least one kind of modified cation / anion such as polyvinylpyrrolidone-vinyl acetate copolymer and the like. The above is used. Above all, polyvinylpyrrolidone or hydroxypropylmethylcellulose is particularly preferable because it has excellent ink absorbency, printability in a low-temperature and low-humidity environment, and printability after storage in a high-temperature and high-humidity environment.

The ratio of [aqueous water-absorbent resin] to [the sum of the water-soluble resin and the water-soluble resin having wet heat resistance and low-temperature printability] is between 7: 3 and 1: 9, and When,
The ratio of the water-soluble resin having wet heat resistance and low-temperature printing property is used in the range of 1: 9 to 9: 1, particularly preferably the former is 5: 5 to 2: 8, and the latter is 2: 1. 8 to 4 to 6
Range. If the above range is not met, a record that has a good balance of ink drying properties, image clarity, printability in high-temperature, high-humidity and low-temperature, low-humidity environments, and printability after storage in high-temperature, high-humidity environments Sheets cannot be obtained.

For the purpose of improving blocking resistance, coating strength, adhesion and dye fixability, various aqueous polymers such as alkyd resins, polyester resins, polyvinyl acetate and vinyl acetate are used in the above-mentioned composition. Polymer resin, NBR resin, SBR resin, polyurethane resin, acrylic resin,
Polyamide or the like is used alone, as a mixture, or as a modified product. In particular, the primary particle diameter is 5 to prevent blocking.
It is effective to add 80 μm of organic particles and secondary particles of inorganic particles having a diameter of 5 to 20 μm in the range of 0.1 to 10% based on the resin component. If the amount is less than this range, a sufficient effect for preventing blocking cannot be obtained. On the other hand, if the amount is more than this range, the transparency of the ink receiving layer decreases, which is not preferable. In addition, additives, inorganic compounds, and the like that enhance dye fixing properties can be added. In addition, various surfactants, antioxidants, ultraviolet absorbers, antifoaming agents, various types of highly hydrophilic modified oils, and the like can be mixed and used as long as the effects of the present invention are not impaired.

(Transparent porous layer) When the ink receiving layer of the present invention is a transparent porous aqueous ink receiving layer, it is formed of fine particles / binder resin. As the particle material, methyl methacrylate, n-butyl acrylate,
Examples of organic fine particles such as styrene and inorganic fine particles include colloidal silica, alumina sol, titanium oxide, and zirconia sol. Examples of the binder resin include the above-mentioned aqueous resins (particularly, PVA, polyvinyl acetal, and acrylate). The particle diameter is 0.5μ
m or less (especially 0.3 μm or less) is preferred in terms of transparency. The mixing ratio is a particle / binder ratio of 3/1 to 20/1.
Is preferred in terms of ink absorption / film strength. By making it transparent, the ink drying speed is improved.

The ink receiving layer of the composition described above may be formed by various known methods, for example, gravure coating, gravure reverse coating, roll coating, wire bar coating, blade coating, knife coating, air knife coating. , Comma coat, slot die coat, dip coat, and the like. The thickness applied to the substrate using these methods is 0.1 to 50 when dry.
μm, preferably 3 to 30 μm. If the thickness is less than 0.1 μm, the ink absorption is not sufficient, and if it exceeds 50 μm, economic disadvantages increase, that is, the manufacturing cost increases, which is not preferable. In addition, in order to secure the coating amount, the liquid having the same composition may be coated plural times.

Sublimation transfer ink receiving layer The sublimation transfer ink receiving layer is a receiving layer for receiving a sublimable dye on the surface of a substrate. In the case of sublimation transfer, the thermal transfer image-receiving sheet is conveyed into the printer together with the thermal transfer sheet, and heat is applied by the thermal head. When the heat is applied, the dye layer of the thermal transfer sheet and the dye-receiving layer of the thermal transfer image-receiving sheet come into close contact with each other. When the adhesion is low, there is a problem that the dye transferability, that is, the sensitivity is poor. In order to solve this problem, in the case of an image receiving sheet such as a paper base material which does not require transparency, a receiving layer is provided via a foam layer in order to improve sensitivity and density at the time of printing. However, in this case, the entire image receiving sheet loses transparency. Since the recording sheet of the present invention simulates a transparent material such as a packaging film base material, the recording sheet needs to have transparency, so that a foamed layer cannot be provided. Therefore, in the present invention, the sensitivity is improved by forming a dye-receiving layer via a non-foamed resin layer plastically deformed by heat and pressure, that is, a low-elastic resin layer on a surface of the base sheet that is in contact with the thermal head. .

Examples of the resin forming the low elastic resin layer include resins having a low elastic modulus even at a relatively low temperature, and chlorinated polypropylene is most preferable in terms of low melting point, film strength and transparency. Other resins include acrylic resins, vinyl chloride-vinyl acetate copolymer resins, polyurethane resins, ethylene-vinyl acetate copolymer resins, and acrylic-modified ionomer resins, and specific examples thereof. Industrial KF-11, Soken Chemical RE-
4. HV-70, Nipporan 51 made by Nippon Polyurethane
99 and the like. These resins may be used in combination with the above and other resins, but preferably occupy 30% by weight, more preferably 50% by weight or more. The chlorinated polypropylene to be used is not particularly limited. For example, it can be obtained from the market under the trade name of Supercron (manufactured by Sanyo Kokusaku Pulp) or Hardlen (manufactured by Toyo Kasei Kogyo) and used in the present invention.

The low elastic resin layer is formed by dissolving the resin in a suitable organic solvent or dispersing the resin in an organic solvent or water, for example, by gravure printing, screen printing, or the like.
It is formed by applying and drying by a forming means such as a reverse roll coating method using a gravure plate. The non-foamed resin layer formed as described above requires 1.0 g / m ² or more, and if it is thinner than this, good printing sensitivity cannot be obtained.
Preferred thickness is 3.0g~15g / m ^2. When the base sheet has poor adhesion to the low elastic resin layer as described above, it is preferable to apply a primer treatment or a corona discharge treatment to the surface thereof.

The ink-receiving layer provided on the low-elasticity resin layer is composed of a varnish mainly composed of a resin which easily dyes a coloring material, and if necessary, various additives such as a release agent. I do. The resin which is easily dyed is used as a homo- or copolymer, anion, or cation-modified product such as vinyl chloride vinyl chloride resin, polyester resin, styrene acrylonitrile resin, polyurethane resin, polyvinyl butyral resin, and styrene resin. In addition, there are polyolefin resin, polyvinyl chloride resin, polyvinyl acetate, polyacrylate, polyamide resin, ionomer, cellulose derivative and the like.
These alone, or a mixture or a copolymer can be used. The ink receiving layer may contain a release agent in order to prevent thermal fusion with the sublimation transfer sheet during image formation. As the release agent, silicone oil, metal soap, phosphate ester plasticizer or fluorine compound can be used, but silicone oil is particularly preferably used. As the silicone oil, epoxy-modified, alkyl-modified, amino-modified, carboxyl-modified, alcohol-modified, fluorine-modified, alkyl aralkyl polyether-modified, epoxy / polyether-modified, polyether-modified silicone oils are preferably used. A reaction product of a vinyl-modified silicone oil and a hydrogen-modified silicone oil is preferred. The amount of release agent added is
0.2 parts by weight to 3 parts by weight per 100 parts by weight of the receiving layer forming resin.
0 parts by weight is preferred. Organic and inorganic fillers and plasticizers (DOP, DIOP, polymer plasticizer) are also added as necessary. The coating amount of the ink receiving layer is 0.5 g / m ² to 10 g / m ^2.
g / m ² (a numerical value in terms of solid content) is preferred.

Hot Melt Transfer Ink Receiving Layer Many materials such as polyamide, ethylene acrylic acid, EVA, and cationic acrylic polymers are suitable for the hot melt transfer ink receiving layer. In addition, the material itself used as the base material can be used as the receiving layer, and polyethylene terephthalate resin, polycarbonate resin, acrylic resin, polyvinyl chloride resin, polypropylene resin, polystyrene resin, polyvinyl alcohol resin, polyethylene resin, diacetate Resins, triacetate resins, polyimide resins, and the like may be in the form of a film or sheet having a thickness of about 5 to 250 μm, preferably about 50 to 180 μm. Further, an antistatic agent may be applied to a substrate.

(White Porous Layer) The white porous layer provided on the recording sheet of the present invention is formed of thermoplastic organic particles alone or thermoplastic particles and a binder. As the thermoplastic organic particle material, EVA resin, polyolefin resin, PMMA resin, polystyrene resin, SBR resin, N
Uniform or copolymerized emulsion particles of a BR resin, an acrylate resin, a polyester resin, a vinyl chloride resin, a polyamide resin, a polyurethane resin and the like are preferable. The particle diameter is preferably from 0.3 to 50 μm. In particular, those having a range of 0.5 to 15 μm are favorable in terms of whiteness and film strength. As the minimum film forming temperature of the particles, those having a temperature of 30 ° C. to 150 ° C. are preferable. Good. 30 °
When the temperature is lower than C, the whitening does not occur, and when the temperature is higher than 150 ° C., the whitening hardly disappears. When the white porous layer is used alone with organic particles, core / shell or core / hair type layered organic particles having a minimum film forming temperature difference can be used.

As the binder, various aqueous resins are used, for example, polyester resin, polyurethane resin, polyamide resin, polyacrylic acid resin, polyacrylate resin, polyethylene acrylate resin, EV
A resin, SBR resin, NBR resin, ionomer resin,
A water-soluble resin or the like is used. The ratio of the particles to the binder resin is preferably in the range of 20/1 to 1/10 from the viewpoint of film strength and whiteness. The whiteness can be adjusted by changing the pore size of the porous layer according to the solvent composition, drying conditions, particle size, particle / binder ratio, combination and the like. Transparency is mainly manifested by the fact that the particles dissolve and lose their particle shape. In addition to this, the white porous layer is a poor solvent method,
Formed by the elution method. In this case, the resin skeleton dissolves and the pores disappear, or the resin skeleton is miniaturized and becomes transparent.

Organic particles having a primary particle diameter of 5 to 80 μm or secondary particles having a diameter of 5 to 20 μm
It is effective to add the inorganic particles of 0.1 to 10% with respect to the resin component. In addition, various surfactants, antioxidants, ultraviolet absorbers, antifoaming agents, various modified oils, and the like can be mixed and used as long as the effects of the present invention are not impaired.

The white porous layer of the composition described above may be formed by various known methods, for example, gravure coat, gravure reverse coat, roll coat, wire bar coat, blade coat, knife coat, air knife. Any method such as a coat, a comma coat, a slot die coat, and a dip coat may be used. The thickness applied to the substrate using these methods is 0.1 to 50 when dry.
μm, preferably 3 to 20 μm. If the thickness is less than 0.1 μm, the degree of whiteness is insufficient, while if it exceeds 30 μm, the transparency after heating and transparency is reduced, which is not preferable. In addition, in order to secure the coating amount, the liquid having the same composition may be coated plural times.

As a method for making the white porous layer transparent, a method of directly heating the white porous layer with a thermal head or a polyethylene terephthalate film (thickness) which is heat-treated on the white porous layer is used. 10-20
(about μm) and heating with a thermal head from the side of the heat-resistant treatment, or a method of stacking a transparent ribbon film subjected to heat treatment on the white porous layer and heating with a thermal head. In the case of (1), the transparent ribbon can be used in the same state as the ink ribbon.
There is an advantage that a thin film of 5 μm can be used.

(Anti-Curl / Antistatic Layer) The same ink-receiving layer as the anti-curl / antistatic layer may be provided on the surface (back surface) of the substrate opposite to the surface on which the ink-receiving layer is formed. . For the purpose of curling prevention, it is possible to use the same water-soluble resin as the ink receiving layer on the surface, an acrylic resin, a polyester resin, and the like, and in particular, use an acrylic resin or a modified acrylic resin or a polyester resin. It is also useful in terms of imparting anti-blocking properties and slip properties. The thickness of the curl prevention layer is preferably about 0.1 to 50 μm when dried, and a method similar to the above-described method for forming the ink receiving layer can be selected.

Further, in order to prevent the recording sheet from being contaminated by dust and to ensure the stability of conveyance by a printer, an antistatic layer containing the following antistatic agent can be provided.
As the antistatic agent, conventionally known cations, anions,
Either zwitterionic or nonionic antistatic agents can be used. Examples thereof include cationic antistatic agents such as quaternary ammonium salts and polyamine derivatives, anionic antistatic agents such as alkyl phosphates, and nonionic antistatic agents such as fatty acid esters. The antistatic layer may be added with the above antistatic agent and a lubricant such as an organic or inorganic filler, and a compounded solution obtained by dissolving or dispersing them in a solvent by a known method, that is, gravure coating, gravure reverse coating. , Roll coating, etc.,
Dry and form. The thickness of the antistatic layer is about 0.001 to 0.1 μm when dried.

(Primer Layer) The recording sheet of the present invention has an ink receiving layer 1 provided on at least one surface of a base material 2. By providing a primer layer between the ink receiving layer and the receiving layer, the adhesion between the ink receiving layer and the substrate can be enhanced. As the resin used for the primer layer, for example, an alkyd resin, a polyester resin, a polyvinyl acetate resin, a vinyl chloride vinyl acetate copolymer resin, an NBR resin, an SBR resin, a polyurethane resin, an acrylic resin, a polyamide, etc., alone or as a mixture or a modified product Used as The modified product is, for example, a product obtained by copolymerizing or grafting a hydroxyl group, a carboxylic acid, or a quaternary ammonium salt-containing monomer to increase the adhesiveness and hydrophilicity.

In order to improve the adhesion of the primer layer and the strength of the coating film, the above resin may be crosslinked with various curing agents, for example, epoxy resin, melamine resin, isocyanate and the like. The method for forming the above-mentioned primer layer,
A method similar to the above-described method for forming the ink receiving layer can be selected.
The thickness of the primer layer is 0.01 to 50 μm when dry.
m, preferably 0.1 to 10 μm. If the thickness is less than 0.1 μm, sufficient performance in adhesiveness is not exhibited, while if it exceeds 10 μm, the end face becomes sticky when the recording sheet is cut, which leads to high production costs. Is not preferred.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for producing a recording sheet according to the present invention will be described below. (Example 1) In Example 1, first, an ink-jet ink receiving layer was formed on one surface of a substrate, and then a white porous layer which was made transparent by heating was formed on the surface of the substrate opposite to the ink receiving layer. Thus, a recording sheet of the present invention was manufactured.

<Formation of Ink Receiving Layer> The following ink receiving layer composition was coated on a transparent polyethylene terephthalate film ("Q80D" manufactured by Toray Industries, Ltd.) having a thickness of 100 g / m as a base material at a dry coating amount of 10 g / m2. ² was applied by a bar coating method. After application, 120 ° C, 5
Drying was performed under the conditions of minutes to form an inkjet ink receiving layer. [Ink receiving layer composition] Water-soluble resin: polyvinyl alcohol ("PVA217", Kuraray Co., Ltd.) Polymerization degree 1700, saponification degree 88 mol% 100 parts

<Formation of White Porous Layer> On the opposite surface of the substrate on which the ink receiving layer obtained above was formed, the following ink composition was dried at a solid content of 10 g / m ^2. A white porous layer was formed by coating with a bar coat method. Drying was performed by air drying under the condition of 5 minutes. [Ink composition] Organic particles: EVA particles (average particle size: 6 μm) 40% aqueous solution 10 parts (solid content) (“Chemipearl V300” manufactured by Mitsui Petrochemical Co., Ltd.) Aqueous resin: 25% aqueous solution of ethylene acrylic acid copolymer resin 1 (Solid content) (“Hi-Tech S-3121” manufactured by Toho Chemical Co., Ltd.)

As a result, a recording sheet of the present invention was completed in which an ink-jet ink receiving layer was formed on the surface of the transparent substrate, and a white porous layer which became transparent by heating was formed on the back surface. After forming a full-color image on the ink receiving layer surface of the recording sheet with an ink jet printer, the white porous layer on the back surface was heated using a thermal transfer printer to record a white image in synchronization with the front image, and the front image was recorded. An image similar to the print, which was concealed in white, was obtained on the back surface of.

Example 2 In Example 2, a hot-melt transfer ink-receiving layer was first formed on one surface of a substrate, and then a white color, which was made transparent by heating, on the surface of the substrate opposite to the ink-receiving layer. The recording sheet of the present invention was manufactured by forming a porous layer.

<Formation of Ink Receiving Layer> Thickness, 100 μm
The following ink-receiving layer composition was applied to a transparent polyethylene terephthalate film ("T-60" manufactured by Toray Industries, Inc.) by a bar coating method so that the coating amount when dried was 3.0 g / m ² . . After the application, drying was performed at 120 ° C. for 5 minutes to form a hot-melt transfer ink receiving layer. [Ink receiving layer composition] Receiving layer resin: 100 parts of a cationic acrylic resin 30% IPA solution (“Elecond PQ-50B” manufactured by Soken Chemical Co., Ltd.)

<Formation of White Porous Layer> On the opposite surface of the substrate on which the ink receiving layer obtained above was formed, the following ink composition was dried at a solid content of 10 g / m ² at a ratio of 10 g / m ^2. A white porous layer was formed by coating with a bar coat method. Drying was performed by air drying under the condition of 5 minutes. [Ink composition] Organic particles: 10 parts of 40% aqueous solution of ethylene-based particles (average particle size: 2 μm) (solid content) (“Aquatex 909” manufactured by Chuo Chemical Industry Co., Ltd.)

As a result, the recording sheet of the present invention was completed, in which the receiving layer of the hot-melt transfer ink was formed on the surface of the transparent base material, and the back surface had a white porous layer which became transparent by heating. After forming a full-color image on the ink receiving layer surface of the recording sheet with a heat-sensitive fusion transfer printer, the white porous layer on the back surface was heated using a thermal transfer printer to record a white image in synchronization with the front image, An image similar to the print, which was concealed in white on the back surface of the front image, was obtained.

[0049]

According to the recording sheet of the present invention, an ink-receiving layer for ink jet recording, sublimation transfer recording or hot melt transfer recording is provided on the surface of a transparent base material, so that any image can be formed by these means. . On the other hand, since a white porous layer which becomes transparent by heating is provided on the substrate surface opposite to the receiving layer, an arbitrary transparent portion can be formed. That is, since the portion opposite to the transparent portion becomes a white image, it is possible to express the effect of white underprinting on a transparent film in general printing such as gravure printing, overlapping or separately from the surface image. In another embodiment of the recording sheet of the present invention, on at least one surface of a transparent substrate, since a white porous layer that is made transparent by heating is provided, a white image is formed on the recording sheet, The image can be examined by superimposing it on a separate recording sheet on which a full-color image or the like is recorded.

[Brief description of the drawings]

FIG. 1 is a sectional view of a recording sheet of the present invention.

FIG. 2 is a cross-sectional view showing a state where an image is formed on a recording sheet of the present invention.

FIG. 3 is a diagram for explaining a use state of a recording sheet according to claim 7 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink receiving layer 2 Base material 3 White porous layer 4 Image 5 Transparency part 6 Curling prevention / antistatic layer 7 Temporary adhesive layer

Claims (7)

[Claims] 1. A recording sheet comprising an ink receiving layer provided on one surface of a transparent substrate and a white porous layer which is made transparent by heating on the other surface of the substrate. 2. The recording apparatus according to claim 1, wherein the ink receiving layer comprises an ink jet ink receiving layer, the image is formed by an ink jet printer, and the white porous layer is made transparent by a thermal transfer printer. Sheet. 3. The ink receiving layer according to claim 1, wherein the ink receiving layer comprises a sublimation transfer ink receiving layer, the image is formed by a sublimation transfer printer, and the white porous layer is made transparent by a thermal transfer printer. Recording sheet. 4. An ink receiving layer comprising a hot melt transfer ink receiving layer, wherein image formation is performed by a hot melt transfer printer, and transparency of a white porous layer is performed by a heat transfer printer. Recording sheet as described. 5. The recording sheet according to claim 2, wherein the ink receiving layer is an ink jet ink receiving layer containing an aqueous resin as a main component. 6. The recording sheet according to claim 2, wherein the ink receiving layer is an ink jet ink receiving layer comprising a transparent porous layer. 7. A recording sheet which is used by being superposed on a sheet on which an image has been recorded on a transparent substrate, wherein a white porous layer which is made transparent by heating is provided on at least one surface of the transparent substrate. A recording sheet provided.