JP4530006B2 - Double-sided recording medium and method for manufacturing double-sided recording medium - Google Patents

Description

  The present invention relates to a recording medium having ink jet recording suitability on one side and thermal recording suitability on the opposite side.

  The ink jet recording method using water-based ink is suitable for terminal printers, facsimiles, plotters, form printing, etc. for reasons such as low noise during recording, easy colorization, and high-speed recording. Application is underway. High-quality paper and coated paper used for general printing have poor ink absorbability, so the printed ink will not dry on the paper surface and will remain for a long time, contaminating the device and continuously printed sheets. Since the image is dirty, it is not practical. In order to solve these problems, a recording paper having a low sizing degree is used (Japanese Patent Laid-Open No. 52-53012), or a base paper in which urea-formalin resin is internally added is impregnated with a water-soluble polymer (Japanese Patent Laid-Open No. 53). -49113 gazette) is disclosed. Further, a recording paper (Japanese Patent Laid-Open Nos. 55-51583 and 56-148585) coated with various porous inorganic pigments such as amorphous silica on the surface for the purpose of improving the color development and reproducibility of the ink. No. Gazette) is disclosed. In addition, for the purpose of obtaining high-definition images with reduced blurring, improvements such as defining physical properties of these porous pigments have been proposed (Japanese Patent Laid-Open Nos. 58-110287 and 59-185690). JP, 61-141484, A).

Also, as the ink jet recording system becomes general, the purpose of both the suitability as office paper such as the writing property with a pencil and the recording suitability is disclosed in Japanese Patent Laid-Open No. 4-16379. It has been proposed to use quality pigments in combination as appropriate, and has achieved some results. However, the development of inkjet printer technology in recent years has been remarkable, and recently, there are also developments that are almost comparable to the image quality of silver halide photography, but as the accuracy of the printer has improved and it has penetrated into offices and homes, so far A new request has emerged that could not be seen too much. One of these is high-speed double-sided recording.

The ink jet recording method is a method of recording by causing the ejected ink droplets to land on the surface of the recording medium. Therefore, it is necessary to improve the landing accuracy in order to obtain a recorded material with high accuracy and excellent image reproducibility. For this reason, the direction in which ink is ejected from the head is limited to the direction in which gravity is applied, that is, the direction from top to bottom, and it is difficult to record both sides simultaneously. Although it is possible to invert the recording medium and record the opposite side after recording one side, it is not a means for speeding up, it is practical because the mechanism of the printer becomes complicated and the size increases It's hard to say.

By the way, considering the practical usage of the printer, the case where high-speed double-sided recording is most urgently needed is when a large amount of double-sided printing is required. In ordinary households, this is equivalent to printing postcards such as New Year's cards, summer greetings, greetings, and invitations. In these cases, various designs and characters are recorded on the back side, but the front side is usually only the address, and there is almost no problem in monochrome printing. However, when this is processed only by the conventional ink jet printer, it has been necessary to reset all sheets to the printer again after the recording on one side is completed and to perform recording on the opposite side.
JP 52-53012 A JP-A-53-49113 JP-A-55-51583 JP-A-56-148585 JP 58-110287 A JP 59-185690 A JP 61-141484 A JP-A-4-16379

An object of the present invention is to solve the above problems, and to provide a recording method capable of high-speed double-sided recording and at least one side suitable for color recording and a recording medium suitable for the method. Provided is a double-sided recording medium for thermal recording and inkjet recording in which the solvent in the inkjet ink does not cause fogging in the thermal recording layer and the printing of the thermal recording layer is not erased.

As a result of intensive studies, the present inventors have imparted ink jet recording suitability to one side, thermal recording suitability to the opposite surface, and a 10% aqueous solution of polyethylene glycol dripped onto the surface to which ink jet recording suitability has been imparted. It has been found that a recording medium capable of answering the above-mentioned demand can be provided by setting the time until penetrating to the provided surface to be 30 seconds or more, and the present invention has been completed. Preferably, it has been found that a recording medium suitable for high-speed double-sided recording can be obtained by providing an intermediate layer between the recording medium substrate and the thermosensitive recording layer.

The present invention includes the following embodiments.
[1] Double-sided recording medium provided with ink-receiving property by forming an ink-receiving layer on one side of a paper base material mainly composed of pulp and provided with a heat-sensitive recording layer on the opposite side (however, inkjet recording by heating) The ink receiving layer contains a xerogel porous pigment, and 0.5 ml of a 10% aqueous solution of polyethylene glycol is dropped with a microsyringe onto a surface having ink jet recording suitability. A double-sided recording medium, characterized in that the time until it penetrates into the layer surface is 30 seconds or more.
[2] The double-sided recording medium according to [1], wherein a protective layer containing a resin is provided on the thermosensitive recording layer.
[3] The double-sided recording medium according to [2 ], wherein the protective layer resin contains at least one of acetoacetyl-modified polyvinyl alcohol and polyvinyl alcohol having an average polymerization degree of 800 or more .

The present invention is a recording medium capable of high-speed double-side recording, at least one side suitable for color ink jet recording, and one side thermal recording. Thermal recording and inkjet recording double-sided recording medium that does not cause blurring on the inkjet recording surface, does not cause fogging of the thermal recording layer due to the solvent in the inkjet ink, and does not erase the print on the thermal recording layer Met.

The pulp for paper used for the support of the present invention includes chemical pulp such as softwood bleached kraft pulp (hereinafter referred to as NBKP) and hardwood bleached kraft pulp (hereinafter referred to as LBKP), mechanical pulp such as GP, BCTMP, MP, and kenaf. Pulp obtained from non-wood raw materials such as, and papermaking pulp represented by pulp such as DIP. Based on this, polyolefin fibers such as polyethylene, polypropylene, ethylene / propylene copolymer, polystyrene, ethylene / vinyl acetate copolymer, halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride, 6-nylon, 66 -Polyamide fiber such as nylon, polyethylene succinate, polycaprolactone, polylactic acid, aliphatic polyester fiber such as polyhydroxybutyrate / valerate copolymer, vinylon fiber and the like may be mixed. If necessary, inorganic pigments such as talc, kaolin, calcined kaolin, calcium carbonate, white carbon, amorphous silica, diatomaceous earth, titanium oxide, activated clay, barium sulfate, organic pigments such as urea formalin resin, nylon powder, polyethylene powder, etc. Is added as a filler, and can be prepared by an ordinary method using acidic or neutral papermaking.

Furthermore, sizing agents represented by rosin-based sizing agents, alkenyl succinic anhydrides, alkyl ketene dimers, etc., starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, methylcellulose, ethylcellulose , Cellulose derivatives such as carboxymethyl cellulose, methoxy cellulose, hydroxy cellulose, fully saponified or partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, polyacrylamide, polyvinyl pyrrolidone, acrylic acid amide / acrylic acid ester Copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride Polymer alkali salts, water-soluble polymers such as casein, polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylate ester, polybutyl methacrylate, styrene / butadiene copolymer, vinyl chloride / vinyl acetate copolymer, styrene / A base paper to which an adhesive represented by latex such as butadiene / acrylic copolymer is internally added or coated can be used as appropriate.

In order to give ink jet recording suitability, it can be obtained by applying or impregnating a paper base material with a cationic resin and / or a water-soluble resin or a water-dispersible resin (high-quality paper type). Therefore, it is necessary to provide a pigment-containing layer. The present invention requires an ink receiving layer containing a xerogel-based porous pigment on one side in order to impart excellent ink jet recording suitability. The order in which the ink-receiving layer and the heat-sensitive layer are provided is not particularly limited. However, if the ink-receiving layer is provided first and the heat-sensitive recording layer coating step is performed later, coloring stains due to rubbing of the heat-sensitive recording layer may be minimized. It is possible and preferable. As pigments contained in the ink receiving layer, amorphous silica, alumina, calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, silicic acid Examples thereof include inorganic pigments such as magnesium, white carbon, alumina, and aluminum hydroxide, and organic pigments such as styrene, acrylic, urea resin, melamine resin, and benzoguanamine resin.

Among these, a xerogel porous pigment is used as the pigment of the ink receiving layer. For example, (1) a method in which a hydrogel-forming substance such as aluminum hydroxide, alumina, silica, magnesium oxide or the like is used as a raw material, such hydrogel is dried to form a xerogel, and then pulverized and classified.
(2) Granulate to the appropriate secondary and tertiary aggregate size in the hydrogel state, and after drying, further heat treatment to promote sintering, crystallization, etc., between the primary particles of the oxide A method of strengthening bonding.
(3) At the stage of producing urea-formalin resin, melamine-formalin resin, etc. in a fine particle suspension of colloidal silica, colloidal alumina, etc., by adjusting the production conditions, the desired secondary particle size can be obtained. The method of using after making it the granulated microparticle, drying, and also using as the particle | grains sintered as needed.
Etc., and can be produced using various known methods and are commercially available. Among these, silica pigments are preferably used for inkjet recording media because they have excellent ink receptivity and high recording density due to properties such as relatively low refractive index and easy control of the porous structure. .

Further, when a pigment of 1 μm or less is contained as a pigment of the ink receiving layer, an ink receiving layer having excellent surface gloss can be obtained. In particular, for applications that require recording with excellent gloss, it is preferable to use fine silica having a secondary particle average particle size of 500 nm or less formed by agglomeration of primary particles of 3 to 40 nm as a main pigment.

Resins (having a binder function) include starch and derivatives thereof, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymers such as casein, gelatin and soybean protein, polyvinyl alcohol and silyl Modified polyvinyl alcohol, polyvinyl alcohol derivatives such as cation-modified polyvinyl alcohol, polyvinyl butyral resin, polyethyleneimine resin, polyvinylpyrrolidone resin, poly (meth) acrylic acid resin, acrylate resin, polyamide resin, polyacrylamide Resin, polyester resin, urea resin, melamine resin, styrene / butadiene copolymer, methyl methacrylate / butadiene copolymer, vinyl copolymer such as ethylene / vinyl acetate copolymer It can be used an aqueous solution or dispersion of the fat, or the known material modified polymer or the like by introducing anionic or cationic residue in the above resins as appropriate.

Furthermore, for the purpose of improving the water resistance of printed images with water-based inks, polyethyleneimine resins, polyamine resins, polyamide resins, polyamide epichlorohydrin resins, polyamine epichlorohydrin resins, polyamide polyamine epichlorohydrin resins, polydiallylamine resins Cationic polymer compounds such as dicyandiamide condensate can also be used in combination. Further, if necessary, pigment dispersants, thickeners, antifoaming agents, foam suppressors, foaming agents, mold release agents, penetrating agents, wetting agents, thermal gelling agents, lubricants, and various other aids known in the art. Agents can also be used.

The means for coating the ink receiving layer can be appropriately selected from commonly used coating means such as size press, gate roll, roll coater, bar coater, air knife coater, rod blade coater, blade coater.

Thermal recording suitability is imparted to the surface opposite to the surface imparted with inkjet suitability. In thermal recording, a colorless or light leuco dye and a thermal recording layer containing a color developing agent as a main substance when heated are heated by a thermal head or the like to react the leuco dye with the color developer. Colored and recorded. This method is suitable for various printers, facsimiles and the like because the maintenance of the machine device is easy. In thermal recording, the positional relationship between the recording head and the recording layer is not limited as in inkjet recording, and the apparatus can be downsized.

Examples of the leuco dye contained in the heat-sensitive recording layer include triphenylmethane, fluorane, and diphenylmethane compounds, which can be selected from conventionally known ones. For example, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, crystal violet lactone, 3- (N-ethyl-N -Isopentylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) ) Fluorane, 3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-dibutylamino-6- Methyl-7-anilinofluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-7- (o Chloroanilino) fluorane, 3-diethylamino-7- (m-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methylfluorane, 3-cyclohexylamino- Selected from 6-chlorofluorane, 3- (N-ethyl-N-cyclohexyl) -6-methyl-7- (p-chloroanilino) fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane and the like At least one kind can be used.

As the developer contained in the heat-sensitive recording layer, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4- Bis (1-methyl-1- (4′-hydroxyphenyl) ethyl) benzene, 1,3-bis (1-methyl-1- (4′-hydroxyphenyl) ethyl) benzene, dihydroxydiphenyl ether, benzyl p-hydroxybenzoate Bisphenol S, 4-hydroxy-4′-isopropyloxydiphenyl sulfone, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,7-di (4-hydroxyphenylthio) -3,5-dioxaheptane, 3,3′-diallyl-4,4′-dihydroxydiphenylsulfone, N- (p-toluenesulfonyl)- '-Phenylurea, N- (p-toluenesulfonyl) -N'-(p-methoxyphenyl) urea, N- (p-toluenesulfonyl) -N '-(o-tolyl) urea, N- (p-toluene) Sulfonyl) -N ′-(m-tolyl) urea, N- (p-toluenesulfonyl) -N ′-(p-tolyl) urea, N- (p-toluenesulfonyl) -N′-benzylurea, 4,4 ′ -Bis (p-toluenesulfonylaminocarbonylamino) -diphenylmethane, 4,4'-bis (o-toluenesulfonylaminocarbonylamino) -diphenylmethane, 4,4'-bis (benzenesulfonylaminocarbonylamino) -diphenylmethane, 1, 2-bis [4 ′-(p-toluenesulfonylaminocarbonylamino) phenyloxy] ethane, 4,4′-bis (p-toluenesulfo Le aminocarbonylamino) ether and 3,3'-bis (p over toluenesulfonyl aminocarbonylamino) at least one diphenyl sulfone is used.

As binders, polyvinyl alcohols of various molecular weights, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, acrylic acid amide / acrylic acid ester copolymer A water-soluble polymer material such as a polymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein; Vinyl acetate, polyurethane, styrene / butadiene copolymer, polyacrylic acid, polyacrylate ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene / vinyl acetate copolymer, Fine styrene / butadiene / acrylic copolymer latex polymer and the like can be used.

Furthermore, a heat-fusible substance (so-called sensitizer) can be used in combination in the heat-sensitive recording layer. As the sensitizer, a thermofusible organic compound having a melting point of 50 to 150 ° C. is used, and examples thereof include 1-hydroxy-2-naphthoic acid phenyl ester, benzyl naphthyl ether, dibenzyl terephthalate, p-benzyloxybenzoate. Acid benzyl, diphenyl carbonate, ditolyl carbonate, m-terphenyl, 1,2-bis (phenoxy) ethane, 1,2-bis (m-tolyloxy) ethane, 1,5-bis (p-methoxyphenoxy) -3- Oxapentane, oxalic acid diesters, 1,4-bis (p-tolyloxy) benzene, benzenesulfoanilide, 2-chloroacetoacetanilide, 4-ethoxymethylsulfonylbenzene, 4-methoxyacetoacetanilide, o-methylacetanilide, 4-methoxy Benzenesulfoanilide, 3,4-dimethyl Le acetanilide, and the like 2-methoxybenzenesulfonyl anilide.

The heat-sensitive recording layer of the present invention may contain pigments and waxes. Examples of pigments include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, calcined clay, talc, and surface-treated inorganic fine powders such as calcium carbonate and silica. Other examples include urea-formalin resins, styrene / methacrylic acid copolymers, and organic fine powders such as polystyrene resins. Among these, an oil-absorbing pigment having an oil absorption of 70 ml / 100 g or more is preferable. As the wax, for example, known ones such as paraffin, amide wax, bisimide wax, metal salt of superabsorbent fatty acid can be used. If necessary, a storage stabilizer, a colorant, and other auxiliaries are appropriately added to the heat-sensitive recording layer of the present invention.

It is also possible to provide an undercoat layer for the purpose of improving sensitivity and preventing head fuzz under the heat-sensitive recording layer, and further providing a protective layer for the purpose of improving storage stability and printability. It is also possible to provide in the upper layer. The printer used in the present invention preferably has two recording units, an ink jet recording unit and a thermal recording unit. Both recording units may be ordinary single recording units. That is, the inkjet recording unit does not have to be particularly different from that of a commercially available inkjet printer, and the thermal recording unit is different from that of a thermal recording printer. However, it is desirable that the head of the thermal recording unit is upward or sideways, and it is further preferable that the thermal recording unit is positioned in front of the ink jet recording unit. When the thermal recording unit faces downward, it is not preferable because the recording paper needs to be reversed for ink jet recording for the above-mentioned reason. If there is an inkjet recording unit in front of the thermal recording unit, thermal recording is performed after the inkjet recording. For thermal recording, it is necessary to place a platen roll in the area where the head hits. Immediately after recording by inkjet, nip between this platen roll and the thermal head may cause contamination of the platen roll with undried ink. is there. In addition, when the paper is swollen due to water-based ink, wrinkles or the like may occur. The recording head may be either a serial head or a line head for both the ink jet recording unit and the thermal recording unit, but is preferably a line head for high-speed recording.

As described above, the ink jet recording unit of the printer used in the present invention may be similar to a commercially available ink jet printer. The recording head may be a serial head or a line head, but is preferably a line head for high-speed recording. Further, the ink to be used is not particularly limited. The water-based ink used in the present invention contains at least one of a water-soluble direct dye, a water-soluble acidic dye, and a color pigment as a dye. Contains glaze etc. Examples of water-soluble direct dyes include CI. Direct black, CI. Direct yellow, CI. Direct Blue, CI. Direct red and the like, and water-soluble acid dyes include CI. Acid Black, CI. Acid Yellow, CI. Acid Blue, CI. Although acid red etc. can be mentioned, it is not necessarily limited to these.

Wetting agents and dye solubilizers include alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol and glycerin and derivatives thereof, nitrogen compounds such as formamide, dimethylacetamide and N-methyl-2-pyrrolidone, dimethyl sulfoxide, Sulfur compounds such as sulfolane are included.

Among these, substances that induce color development of the heat-sensitive recording layer are also included, so if the base material is easy to permeate the wetting agent, dye-dissolving agent, etc. in the ink, it will be added to the heat-sensitive recording layer. It may permeate to induce color development and cause a so-called fogging phenomenon. In addition, the wetting agent and dye solubilizing agent in the ink also contain a substance that induces decoloration of the color developing portion of the heat-sensitive recording layer, which may cause the image of the heat-sensitive recording layer to disappear. Therefore, it is necessary to prevent such solvents as wetting agents and dye solubilizers from penetrating the heat-sensitive recording layer.

The penetration of the solvent should be substantially prevented by setting the time until the 10% aqueous solution of polyethylene glycol dripped onto the surface imparted with inkjet recording suitability to penetrate into the surface imparted with thermal recording suitability is 30 seconds or more. Can do. Preferably it is 35 seconds or more. There is no particular upper limit because there is no harmful effect even if the penetration of the solvent is completely prevented. 0.5 ml of a 10% aqueous solution of polyethylene glycol is dropped on a surface imparted with ink jet recording ability with a microsyringe, and this is observed from the surface of the heat-sensitive recording layer, and the time until the time when three transparent spots appear is measured. Solvent permeation resistance.

There are various methods for increasing the penetration time to 30 seconds or more, such as thickening the base material, increasing the sizing degree of the base material, and selecting the type and amount of the resin of the ink receiving layer (in the present invention). First aspect). Moreover, although the method of using the base material which does not permeate | transmit a solvent is also possible, there exists a possibility that a blur may generate | occur | produce. When an intermediate layer is provided between the ink jet recording layer and the support, the absorbability of the ink jet ink is often lowered, and there is a possibility that bleeding occurs in the ink jet recorded image. Therefore, a recording body in which an intermediate layer is provided between the support and the heat-sensitive recording layer is preferable.

The resin contained in the intermediate layer includes starch and derivatives thereof, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymers such as casein, gelatin and soybean protein, polyvinyl alcohol, silyl-modified polyvinyl alcohol, and cation-modified polyvinyl. Polyvinyl alcohols such as alcohol, polyvinyl butyral resin, polyethyleneimine resin, polyvinylpyrrolidone resin, poly (meth) acrylic acid resin, acrylate resin, polyamide resin, polyacrylamide resin, polyester resin, urea resin , Melamine resin, styrene / butadiene copolymer, methyl methacrylate / butadiene copolymer, aqueous solution or dispersion of vinyl copolymer resin such as ethylene / vinyl acetate copolymer , Or it can be used as appropriate known material modified polymer or the like by introducing anionic or cationic residue in the above resins. Of these, substances that are particularly effective in preventing solvent penetration are polyvinyl butyral resins, styrene / butadiene copolymers, polyvinyl alcohols having an average degree of polymerization of 800 or more, and the like.

The intermediate layer of the present invention may contain a pigment as necessary, calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, silicic acid Inorganic pigments such as calcium, magnesium silicate, white carbon, alumina, aluminum hydroxide, and organic pigments such as styrene, acrylic, urea resin, melamine resin, and benzoguanamine resin can be used.

Intermediate layer 2 to 15 g / m ² as a solid weight as coated amount, preferably from 4~8g / m ^2, if less than 2 g / m ² difficult to obtain the effect of anti-solvent permeable, 15 g / m ² When the amount is larger, there is no problem with respect to the solvent permeation resistance, but it is often disadvantageous in terms of operation or economy.

Further, by providing a protective layer containing a resin on the heat-sensitive recording layer, it is possible to prevent the ink on the ink jet recording surface from adversely affecting the adjacent heat-sensitive recording layer even if the recording medium is overlaid after recording. Preferably, the protective layer contains acetoacetyl-modified polyvinyl alcohol or polyvinyl alcohol having an average polymerization degree of 800 or more. As a result, excellent ink-jet ink resistance is obtained, and there is no adverse effect on the heat-sensitive recording surface even when high-speed double-side recording is performed.

If the recording medium is overlapped immediately after the ink jet recording is performed on the recording medium, the ink solvent may move between the recording sheets from the surface of the ink jet recording layer to the surface of the heat sensitive recording layer. Decoloration of the image occurs. In particular, when the recording medium is set in the form of a roll in a recording apparatus and immediately after ink jet recording, the recording medium is rolled up again in the form of a roll. In order to prevent such fogging and decoloring due to the movement of the solvent, it is effective to apply a protective layer on the heat-sensitive recording layer.

Substances effective as a protective layer include cellulose derivatives such as methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, caseins, arabic gum, oxidized starch, etherified starch, dialdehyde starch, esterified starch, and other starches, fully saponified or Partially saponified polyvinyl alcohol, polyvinyl alcohol modified with various functional groups, specifically acetoacetyl-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, amide-modified Polyvinyl alcohol such as polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol and silicon-modified polyvinyl alcohol Although, among others average polymerization degree 800 or more polyvinyl alcohols or acetoacetyl-modified polyvinyl alcohol is most effective.

Further, in order to enhance the effect of preventing the movement of the ink solvent, a curing agent may be added to the coating liquid for forming the protective layer. Examples of the curing agent include glyoxal, methylol melamine, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, boric acid, alum, ammonium chloride and the like. In the protective layer, a pigment can be added as necessary in order to further improve printability and sticking. Specific examples include inorganic pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, colloidal silica, styrene microballs, Examples thereof include organic pigments such as nylon powder, polyethylene powder, urea / formalin resin filler, and raw starch particles.

If necessary, lubricants such as zinc stearate, calcium stearate, stearamide, polyethylene wax, carnauba wax, paraffin wax, ester wax, sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, sodium Various auxiliary agents such as surfactants such as salts, alginates and fatty acid metal salts, UV absorbers such as benzophenone and triazole, antifoaming agents, fluorescent dyes and coloring dyes may be added.

Protective layer coating weight, 0.1 to 10 g / m ² as solid by weight, preferably 0.5 to 5 g / m ^2, is less than 0.1 g / m ² is obtained, the effect of anti-solvent permeability If it is difficult to exceed 10 g / m ² , the sensitivity may be lowered during thermal recording. The recording medium of the present invention can be used not only for high-speed simultaneous recording of ink jet recording and thermal recording, but also for recording when using an ink jet printer, a thermal printer, and each printer alone, if necessary. is there.

Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. In the examples, the number of parts and% mean parts by weight and% by weight. The measuring methods of various physical properties in the examples are shown below.
Example 1
1) Formation of inkjet recording layer 25 parts of an amorphous silica pigment (trade name: Fine Seal X-45, manufactured by Tokuyama) having a specific surface area of 290 m ² / g and an average secondary particle size of 4.3 μm, prepared by a sedimentation method. Amorphous silica pigment (trade name: Fine Seal X-60, manufactured by Tokuyama) having a specific surface area of 290 m ² / g and an average secondary particle size of 5.9 μm, silanol-modified polyvinyl alcohol (trade name: R 1130, manufactured by Kuraray Co., Ltd.) 250 parts of 10% aqueous solution, 10 parts of a polydiallyldimethylammonium chloride cationic resin (trade name: Unisense CP-103, manufactured by Senka) having a molecular weight of about 100,000, and after adding water, A coating liquid for an inkjet recording layer having a concentration of 18% was obtained. Meyer bar so that the coating amount after drying on high-quality paper (using SPK-287 manufactured by Arakawa Chemical Industries as an internal sizing agent) is 10 g / m ² with a grammage of 80 g / m ² After coating and drying using a super-calender, a super calendar process was performed to form an ink jet recording layer.

2) Formation of intermediate layer The coating amount after drying an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average polymerization degree of 1050 on the surface opposite to the ink-receiving layer of the above-mentioned fine paper is 6.0 g / m ^2. Thus, the intermediate layer was formed by drying.
3) Formation of thermosensitive recording layer (1) Dispersion A preparation 3- (N-isopentyl-N-ethylamino) -6-methyl-7-anilinofluorane 20 parts, 10% aqueous solution of polyvinyl alcohol 10%, After mixing 70 parts of water, the mixture was pulverized using a sand grinder until the average particle size became 1 μm or less.
(2) Dispersion B Preparation 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) 20 parts, polyvinyl alcohol 10% aqueous solution 10 parts, and water 70 parts were mixed, then using a sand grinder, It grind | pulverized until the average particle diameter became 1 micrometer or less.
(3) Preparation of Dispersion C After mixing 20 parts of 1,2-bis (phenoxy) ethane, 10 parts of a 10% aqueous solution of polyvinyl alcohol and 70 parts of water, the average particle size is 1 μm or less using a sand grinder. Until crushed.
(4) Formation of heat-sensitive recording layer 50 parts of the above A liquid, 75 parts of the B liquid, 75 parts of the C liquid, 30 parts of calcined clay, 20 parts of 25% zinc stearate dispersion, 15 parts of 30% paraffin dispersion, and 120 parts of 10% polyvinyl alcohol aqueous solution was mixed and stirred to obtain a coating solution. This coating solution was applied and dried on the upper surface of the intermediate layer so that the coating amount after drying was 5.0 g / m ^2, and then a super calender treatment was performed to form a heat-sensitive recording layer.

4) Formation of protective layer 300 parts of a 10% aqueous solution of polyvinyl alcohol having an average polymerization degree of 1050 (manufactured by Kuraray, PVA-110), 15 parts of kaolin (manufactured by EMC, UW-90), 6 parts of a 30% zinc stearate dispersion And 30 parts of water was applied and dried on the heat-sensitive recording layer so that the coating amount after drying was 2 g / m ² to obtain a protective layer.
5) Formation of thermal recording image The recording medium obtained was printed on the thermal recording layer under the conditions of a printing voltage of 21.7 v and a printing pulse of 1.0 ms using a thermal color development tester THPMD manufactured by Okura Electric. A clear black color image with high density was obtained.
6) Formation of inkjet recording image Printing was performed at a recording density of 720 dpi using an inkjet printer PM-700C manufactured by Seiko Epson Corporation. In Example 1, a clear color image with high density was obtained.
7) Evaluation of bleeding of inkjet recording image Using an inkjet printer PM-700C manufactured by Seiko Epson Corporation, 200% density printing was performed at a recording density of 720 dpi, and the bleeding state of portions where different colors were adjacent to each other was visually evaluated. As a result, the case where the blur was hardly recognized was ranked as A, the case where the slight blur was recognized but the level where there was no problem in practical use was ranked as B, and the case where the blur was too large to be practically used was ranked as C.

8) Evaluation of fogging of thermal recording layer 1 (ink penetration fogging)
200% density printing was performed at a recording density of 720 dpi using a Seiko Epson inkjet printer PM-700C, and after standing for 1 week in an environment of 20 ° C. and 65% RH, the occurrence of fogging in the thermal recording layer was visually evaluated. did. As a result, the case where fog was not recognized at all was ranked as A, the case where slight fog was observed but at a level where there was no problem in practical use was ranked as B, and the case where fog was strong and could not be used practically was ranked as C.
9) Fog evaluation 2 of thermal recording layer (ink transfer fog)
Immediately after 200% density printing was performed at a recording density of 720 dpi using an Seiko Epson inkjet printer PM-700C, two recording media were stacked so that the inkjet recording layer and the thermal recording layer were in contact with each other, and 10 g / cm ^2. The sample was left in an environment of 20 ° C. and 65% RH for 1 week while applying a pressure of 2 to evaluate the occurrence of fogging in the heat-sensitive recording layer. As a result, the case where fog was not recognized at all was ranked as A, the case where slight fog was observed but at a level where there was no problem in practical use was ranked as B, and the case where fog was strong and could not be used practically was ranked as C.

10) Evaluation 1 of decoloring of thermal recording image 1 (ink penetration decoloring)
After forming a heat-sensitive recording image by the above method, 200% density printing was performed at a recording density of 720 dpi using an ink jet printer PM-700C manufactured by Seiko Epson Corporation, and left for 1 week in an environment of 20 ° C. and 65% RH. The state of occurrence of decoloring of the recorded image was visually evaluated. As a result, the case where no erasing was recognized was ranked as A, the case where slight erasing was recognized but a level where there was no problem in practical use was ranked as B, and the case where erasing was strong and unbearable was ranked as C.
11) Evaluation 2 of decoloring of thermal recording image (ink transfer decoloring)
After the thermal recording image was formed by the above method, immediately after 200% density printing was performed at a recording density of 720 dpi using an ink jet printer PM-700C manufactured by Seiko Epson, two recording media were separated into an inkjet recording layer and a thermal recording layer. The samples were left in an environment of 20 ° C. and 65% RH for 1 week while applying a pressure of 10 g / cm ² , and the state of occurrence of decoloration of the thermal recording image was visually evaluated. As a result, the case where no erasing was recognized was ranked as A, the case where slight erasing was recognized but a level where there was no problem in practical use was ranked as B, and the case where erasing was strong and unbearable was ranked as C.
12) A solvent-permeable polyethylene glycol 10% aqueous solution (0.5 ml) was dropped on a surface provided with ink jet recording ability with a microsyringe, and this was observed from the surface provided with heat sensitive recording ability. The time until the point of appearance was measured to determine solvent permeation resistance.
The evaluation results are shown in Table 1.

Example 2
A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, an aqueous polyvinyl alcohol solution (manufactured by Kuraray, PVA-117) having an average degree of polymerization of 1750 was used instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050. The evaluation results are shown in Table 1.
Example 3
A recording medium was obtained in the same manner as in Example 1. However, in the formation of the intermediate layer, an aqueous polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., ESREC BBM-5) was used instead of an aqueous polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average polymerization degree of 1050. The evaluation results are shown in Table 1.

Example 4
A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, a styrene-butadiene copolymer (manufactured by ZEON Corporation, Nipol LX430) dispersion was used instead of an aqueous solution of polyvinyl alcohol having an average degree of polymerization of 1050 (manufactured by Kuraray, PVA-110). The evaluation results are shown in Table 1.
Example 5
A recording medium was obtained in the same manner as in Example 1. However, in the formation of the intermediate layer, instead of an aqueous solution of polyvinyl alcohol having an average polymerization degree of 1050 (manufactured by Kuraray, PVA-110), an aqueous solution of starch (manufactured by Oji Constarch, Ace A) is used, and the coating amount is 8 g / m ^2. It was. The evaluation results are shown in Table 1.
Example 6
A recording medium was obtained in the same manner as in Example 1. However, no protective layer was formed. The evaluation results are shown in Table 1.
Example 7
A recording medium was obtained in the same manner as in Example 1. However, in forming the ink jet recording layer, a high-quality paper having a basis weight of 180 g / m ² and a steecht size of 100 seconds (internal sizing agent) was used instead of a high-quality paper having a basis weight of 80 g / m ² and a steecht size of 10 seconds. As SPK-287 manufactured by Arakawa Chemical Industries, Ltd.). Further, the intermediate layer was not coated, the heat-sensitive recording layer was directly coated on the substrate, and the protective layer was not coated. The evaluation results are shown in Table 1.
Example 8
A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, an aqueous polyvinyl alcohol solution (Kuraray, PVA-117) having an average polymerization degree of 1750 was used instead of an aqueous polyvinyl alcohol solution (Pura-110, made by Kuraray) having an average polymerization degree of 1050. The evaluation results are shown in Table 1.
Example 9
A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, an aqueous polyvinyl alcohol (Nippon Gosei Chemical Co., Ltd., Gohsenol NM-11Q) having an average polymerization degree of 1000 to 1500 is used instead of an aqueous polyvinyl alcohol having an average polymerization degree of 1050 (manufactured by Kuraray, PVA-110). used. The evaluation results are shown in Table 1.
Example 10
A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, an aqueous solution of acetoacetyl-modified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., Goosephimer Z-200) was used in place of an aqueous solution of polyvinyl alcohol having an average degree of polymerization of 1050 (Kuraray, PVA-110). . The evaluation results are shown in Table 1.
Example 11
A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, an aqueous solution of acetoacetyl-modified polyvinyl alcohol (manufactured by Nippon Gosei Kagaku Zose 100) was used instead of an aqueous solution of polyvinyl alcohol having an average degree of polymerization of 1050 (manufactured by Kuraray, PVA-110). . The results are shown in Table 1.

Comparative Example 1
A recording medium was obtained in the same manner as in Example 1. However, the intermediate layer was not coated, and the heat-sensitive recording layer was directly coated on the substrate. The evaluation results are shown in Table 1.
Comparative Example 2
A recording medium was obtained in the same manner as in Example 1. However, in the formation of the intermediate layer, an aqueous solution of starch (manufactured by Oji Constarch, Ace A) is used instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average polymerization degree of 1050, and the coating amount is 1 g / m ^2. It was. The evaluation results are shown in Table 1.
Comparative Example 3
A recording medium was obtained in the same manner as in Example 1. However, the intermediate layer was formed under the ink jet recording layer, and the coating amount was 1 g / m ² . The evaluation results are shown in Table 1.

Comparative Example 4
A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, polyvinyl alcohol having an average polymerization degree of 550 (manufactured by Kuraray, PVA-105) is used instead of an aqueous solution of polyvinyl alcohol having an average polymerization degree of 1050 (Kuraray, PVA-110). Was 1 g / m ² . Further, no protective layer was formed. The evaluation results are shown in Table 1.
Comparative Example 5
A recording medium was obtained in the same manner as in Example 1. However, in forming the ink jet recording layer, synthetic paper (YUPO FPG-80, manufactured by Oji Oil Chemical Co., Ltd.) was used instead of high-quality paper having a basis weight of 80 g / m ² and a Steecht size of 10 seconds. The evaluation results are shown in Table 1.

  As is apparent from Table 1, the examples of the present invention were recording media excellent in bleeding, fogging, and decoloring. On the other hand, Comparative Examples 1, 2, 3, and 4 have low solvent permeation resistance and thus cause fogging and decoloring. Further, Comparative Example 5 has high solvent resistance and does not cause fogging or decoloring. That is, the recording medium of the present invention has excellent ink jet recording aptitude and thermal recording aptitude that does not cause any blur, fogging, and decoloring. In the solvent permeation resistance evaluation shown in Table 1, among the samples marked as 60 seconds, those using the synthetic paper of Comparative Example 5 did not penetrate the solvent to the back surface. In other examples using a paper substrate, the value was 60 seconds or more and 1000 seconds or less.

Claims (3)

A double-sided recording medium in which ink-jet recording properties are imparted by forming an ink-receiving layer on one side of a pulp-based paper base material and a heat-sensitive recording layer is provided on the opposite side (however, inkjet recording is transferred by heating) The ink receiving layer contains a xerogel-based porous pigment, and 0.5 ml of a 10% aqueous solution of polyethylene glycol is dropped with a microsyringe onto the surface having ink jet recording suitability to penetrate the surface of the heat-sensitive recording layer. A double-sided recording medium characterized in that the time until completion is 30 seconds or more. The double-sided recording medium according to claim 1, wherein a protective layer containing a resin is provided on the heat-sensitive recording layer. The double-sided recording medium according to claim 2, wherein the resin of the protective layer contains at least one of acetoacetyl-modified polyvinyl alcohol and polyvinyl alcohol having an average degree of polymerization of 800 or more.