JP2000272235A - Perfecting recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an ink jet recording and heat-sensitive recording hybrid perfecting recording medium not generating bleeding on an ink jet recording face nor generating fog and decoloring on a heat-sensitive recording face. SOLUTION: A perfecting recording medium is provided with the ink jet recording adaptability imparted on one face of a paper base composed of a pulp as a main component and having a heat-sensitive recording layer on an opposite face, and when a polyethylene glycol 10% water solution of 0.5 ml micro-syringe is dripped on a face of ink jet recording adaptability, the time before the water solution permeates heat-sensitive recording layer face is 30 seconds or longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium provided with ink jet recording aptitude on one side and thermal recording aptitude on the other side.

[0002]

2. Description of the Related Art An ink jet recording system using an aqueous ink has a low noise at the time of recording, is easy to colorize, and is capable of high-speed recording. Applications to form printing and the like are being promoted. Because high-quality paper and coated paper used for general printing have poor ink absorption,
The printed ink remains on the paper surface without drying for a long time, and contaminates the apparatus and the continuously printed sheet or stains the image. In order to solve such a problem, a recording paper having a low size is used (Japanese Patent Laid-Open No.
No. 53012) and a base paper containing a urea-formalin resin internally impregnated with a water-soluble polymer (Japanese Patent Laid-Open No. 53-4 / 1983).
No. 9113). Further, recording papers coated with various porous inorganic pigments such as amorphous silica on the surface for the purpose of enhancing the color development and reproducibility of the ink (JP-A-55-51583, JP-A-5-51583)
No. 6-148585) is disclosed. Further, for the purpose of obtaining a high-definition image with reduced bleeding, improvements such as defining the physical properties of these porous pigments have been proposed (JP-A-58-110287, JP-A-59-18569).
0, JP-A-61-141584).

With the generalization of the ink jet recording method, the aim is to achieve both the suitability of office paper, such as writing with a pencil, and the suitability of recording, and Japanese Patent Application Laid-Open No. 4-16379 discloses that two types having different pore radii are used. It has been proposed to appropriately use the above-mentioned porous pigments, and a tentative result has been obtained. However, the development of inkjet printer technology in recent years has been remarkable, and recently, those that almost match the image quality of silver halide photographs have been developed.However, as the accuracy of printers has improved and penetrated offices and homes, There were new requests that were not well-reviewed. One of these is high-speed double-sided recording.

[0004] The ink jet recording method is a method in which a flying ink droplet lands on the surface of a recording medium for recording. Therefore, in order to obtain a highly accurate recorded matter having excellent image reproducibility, it is necessary to improve the landing accuracy. Therefore, 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 print on both sides simultaneously. In addition, after recording on one side, it is possible to reverse the recording medium and record on the opposite side, but this is not a means for speeding up, and the mechanism of the printer is complicated and the size is large, so it is practical. Hard to say.

By the way, from the viewpoint of practical use of a printer, high-speed double-sided printing is most urgently required when a large amount of double-sided printing is required. In general households, this is equivalent to printing postcards such as New Year's cards, summer greetings, greeting cards, and invitation cards. In these cases, various patterns and characters are recorded on the back side,
The front side is usually only the address, and in most cases there is no problem in monochrome printing. However, if this is processed only by the conventional inkjet printer,
After the recording on one side was completed, all the sheets had to be set again in the printer, and the recording on the opposite side had to be performed.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a recording method capable of high-speed double-sided recording and at least one side suitable for color recording, and a recording medium adapted to the method. With the goal. Provided is a double-sided recording medium for thermal recording and inkjet recording, in which a solvent in an ink-jet ink does not cause fogging on a heat-sensitive recording layer and does not erase the print on the heat-sensitive recording layer.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have provided inkjet recording suitability on one side, thermosensitive recording suitability on the other side, and polyethylene glycol dropped on the surface provided with inkjet recording suitability. It has been found that a recording medium that can satisfy the above-mentioned demand can be provided by setting the time required for the 10% aqueous solution to permeate the surface provided with the thermal recording suitability to be 30 seconds or longer, and to complete the present invention. Reached. 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 base material and the heat-sensitive recording layer.

[0008] The present invention includes the following aspects. [1] A double-sided recording medium in which a paper base mainly composed of pulp is provided with ink jet recording suitability on one side and a heat-sensitive recording layer is provided on the other side. A double-sided recording medium, wherein the time required for dropping 5 ml of a 10% aqueous solution of polyethylene glycol and permeating the surface of the heat-sensitive recording layer is 30 seconds or more. [2] The double-sided recording medium according to [1], wherein an intermediate layer containing a resin is provided between the paper substrate and the heat-sensitive recording layer. [3] The double-sided recording according to [2], wherein the resin of the intermediate layer contains at least one of a polyvinyl alcohol having an average degree of polymerization of 800 or more, a polyvinyl butyral resin, and a styrene-butadiene copolymer. Medium. [4] The double-sided recording medium according to [1], [2] or [3], wherein a protective layer containing a resin is provided on the heat-sensitive recording layer. [5] The double-sided recording medium according to [4], 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.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As a pulp for paper used for a support of the present invention, softwood bleached kraft pulp (hereinafter referred to as NBK)
P) etc., chemical pulp such as hardwood bleached kraft pulp (hereinafter, LBKP), mechanical pulp such as GP, BCTMP, MP, pulp obtained from non-wood raw materials such as kenaf, DIP
And other paper pulp typified by such pulp. Mainly, polyethylene, polypropylene, ethylene-propylene copolymer, polystyrene, polyolefin-based fibers such as ethylene-vinyl acetate copolymer, polyvinyl chloride, halogen-containing polymers such as polyvinylidene chloride,
Polyamide fibers such as 6-nylon and 66-nylon,
Aliphatic polyester fibers such as polyethylene succinate, polycaprolactone, polylactic acid, polyhydroxybutyrate and valerate copolymers, and vinylon fibers may be mixed. Also, if necessary, talc, kaolin, calcined kaolin, calcium carbonate, white carbon, amorphous silica, diatomaceous earth, titanium oxide, activated clay, inorganic pigments such as 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.

Further, sizing agents represented by rosin sizing agents, alkenyl succinic anhydrides, alkyl ketene dimers, etc., starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, etc. Cellulose derivatives such as methylcellulose, ethylcellulose, carboxymethylcellulose, methoxycellulose, hydroxycellulose, fully or partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, acrylamide. Acrylic ester copolymer,
Acrylic amide / acrylic acid ester / methacrylic acid copolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt of isobutylene / maleic anhydride copolymer, water-soluble polymer such as casein, polyvinyl acetate, polyurethane , Polyacrylic acid, polyacrylate,
It is possible to appropriately use a base paper internally added or coated with an adhesive represented by latex such as polybutyl methacrylate, styrene / butadiene copolymer, vinyl chloride / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer. it can.

In order to impart ink jet recording suitability, it can be obtained by coating or impregnating a paper substrate with a cationic resin and / or a water-soluble resin or a water-dispersible resin (high quality paper type). However, it is preferable to provide a pigment-containing layer in terms of ink absorbability. In particular, it is preferable to provide an ink receiving layer containing a xerogel-based porous pigment on one side in order to impart excellent inkjet recording suitability. The order in which the ink receiving layer and the heat-sensitive layer are provided is not particularly limited, but the ink-receiving layer is provided first, and after the heat-sensitive recording layer coating step, it is possible to minimize coloring stains due to rubbing of the heat-sensitive recording layer. Yes, it is. 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, silicate Inorganic pigments such as magnesium, white carbon, alumina, aluminum hydroxide, styrene, acrylic,
Examples thereof include urea resin-based, melamine resin-based, and benzoguanamine resin-based organic pigments.

Among them, the pigment for the ink receiving layer is preferably a xerogel-based porous pigment. For example, (1) a hydrogel-forming substance such as aluminum hydroxide, alumina, silica, or magnesium oxide is used as a raw material, and such a hydrogel is dried. To make xerogel, then crush,
Classification method. (2) In the state of a hydrogel, granules are formed into appropriate secondary and tertiary agglomerates, dried, and further heated to promote sintering, crystallization, etc., so that oxide primary particles A method of using with strengthened bonding. (3) At the stage of producing urea-formalin resin, melamine-formalin resin, etc. in a suspension of fine particles such as colloidal silica, colloidal alumina, etc., the production conditions are adjusted to produce the desired secondary particle diameter. A method in which, after being formed into fine particles, they are dried and then used as sintered particles as necessary. Can be manufactured using various known methods,
It is commercially available. Among them, silica pigments are preferably used for ink jet recording media because of their relatively low refractive index, easy control of the porous structure, etc., they have excellent ink receptivity and high recording density can be obtained. .

When a pigment of 1 μm or less is contained as a pigment in the ink receiving layer, an ink receiving layer having excellent surface gloss can be obtained. In particular, for applications requiring excellent gloss recording, it is preferable to use fine silica having an average secondary particle diameter of 500 nm or less, in which primary particles of 3 to 40 nm are aggregated, as a main pigment.

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

Further, for the purpose of improving the water resistance of a printed image with an aqueous ink, a polyethyleneimine resin, a polyamine resin, a polyamide resin, a polyamide epichlorohydrin resin, a polyamine epichlorohydrin resin, a polyamide polyamine epichlorohydrin resin,
Cationic polymer compounds such as polydiallylamine resins and dicyandiamide condensates can also be used in combination. Further, if necessary, a pigment dispersant, a thickener, an antifoaming agent, a foam inhibitor,
Foaming agents, release agents, penetrants, wetting agents, thermal gelling agents, lubricants,
Other various auxiliaries known in the art can also be used.

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

The surface opposite to the surface provided with the ink jet suitability is provided with thermal recording suitability. Thermal recording is usually a colorless or light-colored leuco dye, and a heat-sensitive recording layer containing, as a main substance, a developer that develops color when heated, is heated by a thermal head or the like, and the leuco dye reacts with the developer. It is recorded after being colored. This method is suitably used for various printers, facsimile machines, and the like because the maintenance of mechanical devices is easy. Also,
In thermal recording, the positional relationship between the recording head and the recording layer is not restricted as in ink-jet recording, and the apparatus can be downsized.

The leuco dye contained in the heat-sensitive recording layer includes triphenylmethane-based, fluoran-based, and diphenylmethane-based compounds, and 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-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-
(O, p-dimethylanilino) fluoran, 3- (N-
Ethyl-Np-toluidino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-
7-anilinofluoran, 3- (N-cyclohexyl-
N-methylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (m-trifluoromethylanilino) fluoran, 3-diethylamino -6-methyl-7-chlorofluorane, 3-diethylamino-6-methylfluoran, 3-cyclohexylamino-6-chlorofluoran, 3- (N-ethyl-N
-Cyclohexyl) -6-methyl-7- (p-chloroanilino) fluoran and 3-dibutylamino-7-
At least one selected from (o-chloroanilino) fluoran and the like can be used.

As a 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′-isopropyl Oxydiphenyl sulfone, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,7-di (4-hydroxyphenylthio) -3,5-dioxaheptane, 3,3 ′
-Diallyl-4,4'-dihydroxydiphenylsulfone, N- (p-toluenesulfonyl) -N'-phenylurea, N- (p-toluenesulfonyl) -N '-(p-
Methoxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(o-tolyl) urea, N- (p-toluenesulfonyl) -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-toluenesulfonylaminocarbonylamino) diphenyl ether and 3,3'-bis (p-toluenesulfonylaminocarbonylamino) carbonylamino ) At least one such as diphenyl sulfone is used.

As the binder, polyvinyl alcohols having various molecular weights, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, carboxymethylcellulose, methylcellulose and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic acid Ester copolymer, acrylamide / acrylate / methacrylic acid terpolymer,
Water-soluble polymer materials such as styrene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein; and polyvinyl acetate, polyurethane, styrene / butadiene copolymer, polyacrylic acid, and polyacryl. Acid ester, vinyl chloride /
Latexes such as vinyl acetate copolymer, polybutyl methacrylate, ethylene / vinyl acetate copolymer, and styrene / butadiene / acrylic copolymer can be used.

Further, a heat-fusible substance (so-called sensitizer) can be used in the heat-sensitive recording layer. As the sensitizer, a heat-fusible organic compound having a melting point of 50 to 150 ° C is used. Examples thereof include 1-hydroxy-2-naphthoic acid phenyl ester, benzylnaphthyl ether, dibenzyl terephthalate, and p-benzyloxybenzoate. Benzyl acid, 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, benzenesulfonanilide, 2-chloroacetoacetanilide, 4-ethoxymethylsulfonylbenzene,
-Methoxyacetoacetanilide, o-methylacetanilide, 4-methoxybenzenesulfoanilide, 3,4
-Dimethylacetanilide, 2-methoxybenzenesulfoanilide and the like.

The heat-sensitive recording layer of the present invention may contain pigments and waxes. Examples of the pigments include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, calcined clay, talc, and inorganic fine powders such as surface-treated calcium carbonate and silica. Other, urea-formalin resin,
Organic fine powders such as styrene / methacrylic acid copolymers and polystyrene resins can be mentioned. Among these, oil-absorbing pigments having an oil absorption of 70 ml / 100 g or more are preferable. As the waxes, for example, known waxes such as paraffin, amide-based wax, bisimide-based wax, and metal salts of high-absorbency fatty acids can be used.
The heat-sensitive recording layer of the present invention may further contain a storage stabilizer, a colorant, and other auxiliaries as needed.

An undercoat layer for the purpose of improving sensitivity, preventing head scum, and the like can be provided below the heat-sensitive recording layer. Further, a protective layer for the purpose of improving storage stability and printability can be used. It can also be provided above the heat-sensitive recording 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. In other words, the ink jet recording unit need not be different from the recording unit of a commercially available ink jet printer, and the thermal recording unit need not be particularly different from that of a thermal recording printer. However, it is preferable that the head of the thermal recording unit is directed upward or sideways, and it is more preferable that the thermal recording unit be located 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 inverted for inkjet recording for the above-described reason. When an ink jet recording unit is provided before the thermal recording unit, thermal recording is performed after the ink jet recording. For thermal recording, it is necessary to place a platen roll in the area where the head hits.Niping between the platen roll and the thermal head immediately after recording by inkjet may cause contamination of the platen roll by undried ink. is there. Further, when the paper swells and becomes uneven due to the aqueous ink, wrinkles and the like may be generated.
The recording head may be a serial head or a line head for both the ink jet recording unit and the thermal recording unit, but is desirably 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 used is not particularly limited. The aqueous ink used in the present invention contains at least one of a water-soluble direct dye, a water-soluble acid dye, and a coloring pigment as a dye, and further includes a wetting agent, a dye dissolving agent, a preservative, and Contains fungicides and the like. Examples of the water-soluble direct dye include CI. Direct Black, CI. Direct Yellow, CI. Direct Blue, CI. Direct red and the like, and examples of the water-soluble acid dye include CI. Acid Black, CI. Acid Yellow, CI. Acid Blue, CI. Acid Red and the like can be mentioned, but it is not necessarily limited to these.

Examples of the wetting agent and dye dissolving agent 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; It contains sulfur compounds such as dimethylsulfoxide and sulfolane.

Since these substances also include a substance that induces the color development of the heat-sensitive recording layer, if the base material is easy to penetrate the wetting agent, the dye-dissolving agent, etc. in the ink, it is heat-sensitive. It may penetrate into the recording layer to induce color development, causing a so-called fogging phenomenon. Further, since the wetting agent, the dye dissolving agent, and the like in the ink also include a substance that induces decoloration of the colored portion of the heat-sensitive recording layer, the image of the heat-sensitive recording layer may be lost. Therefore, it is necessary to prevent such solvents as the wetting agent and the dye dissolving agent from penetrating into the heat-sensitive recording layer.

The time required for the 10% aqueous solution of polyethylene glycol dropped on the surface provided with ink jet recording suitability to penetrate into the surface provided with thermal recording suitability is at least 30 seconds, so that the penetration of the solvent is substantially reduced. Can be prevented. Preferably, it is at least 35 seconds. There is no particular harm even if the penetration of the solvent is completely prevented, so there is no particular upper limit. 0.5 ml of 10% aqueous solution of polyethylene glycol
Is dropped on a surface provided with inkjet recording suitability by a microsyringe, observed from the surface of the heat-sensitive recording layer, and the time until three transparent spots appear is measured to determine the solvent permeation resistance.

There are various methods for increasing the time required for permeation to be 30 seconds or longer, such as increasing the thickness of the substrate, increasing the size of the substrate, and selecting the type and amount of the resin of the ink receiving layer ( First embodiment of the present invention). Although a method using a base material that does not allow the solvent to pass through is also possible, bleeding may occur. A second aspect of the present invention is to provide an intermediate layer between the heat-sensitive recording layer and the substrate, which does not allow a solvent to permeate, and / or to provide an intermediate layer between the inkjet recording layer and the substrate. When an intermediate layer is provided between the inkjet recording layer and the support, the absorbability of the inkjet ink often decreases, and bleeding may occur in the inkjet recorded image. Therefore, a recording medium in which an intermediate layer is provided between the support and the heat-sensitive recording layer is preferable.

Resins contained in the intermediate layer include starch and derivatives thereof, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymers such as casein, gelatin, soy protein, polyvinyl alcohol and silyl-modified polyvinyl alcohol, Polyvinyl alcohols such as cation-modified polyvinyl alcohol, polyvinyl butyral resin, polyethylene imine resin, polyvinyl pyrrolidone resin, poly (meth) acrylic acid resin, acrylate ester resin, polyamide resin, polyacrylamide resin, polyester resin , Urea resin, melamine resin, styrene
An aqueous or aqueous dispersion of a vinyl copolymer resin such as butadiene copolymer, methyl methacrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, or an anionic or cationic residue in the above resins. Known materials such as the introduced modified polymer can be appropriately used. Of these, substances having particularly excellent solvent permeation prevention effects include polyvinyl butyral resins, styrene / butadiene copolymers, and polyvinyl alcohols having an average degree of polymerization of 800 or more, and these are preferred.

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

The coating amount of the intermediate layer is 2 to 2 as solid weight.
15 g / m ^2, preferably 4~8g / m ^2, 2g /
If less than m ² is difficult to obtain the effect of anti-solvent permeable,
When it is more than 15 g / m ² , there is no problem in terms of solvent permeation resistance, but it is often disadvantageous in terms of operation or economy.

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. it can. Preferably, the protective layer contains acetoacetyl-modified polyvinyl alcohol or polyvinyl alcohol having an average degree of polymerization of 800 or more. As a result, extremely excellent ink jet ink resistance is obtained, and even if high-speed double-sided recording is performed, there is no adverse effect on the heat-sensitive recording surface.

When the recording medium is overlaid immediately after the ink jet recording is performed on the recording medium, the ink solvent may move from the surface of the ink jet recording layer to the surface of the heat-sensitive recording layer between the recording sheets. Fog and decoloration of the recorded image occur. In particular, when the recording medium is set in the recording apparatus in the form of a roll and then wound up again in the form of a roll immediately after the inkjet recording is performed, fog and decoloration of the heat-sensitive recording layer become remarkable. In order to prevent fogging and decoloring due to such solvent movement, it is effective to provide a protective layer on the heat-sensitive recording layer.

Substances effective as a protective layer include cellulose derivatives such as methylcellulose, ethylcellulose, hydroxyethylcellulose and carboxymethylcellulose; starches such as casein, gum arabic, oxidized starch, etherified starch, dialdehyde starch, and esterified starch; Saponified or partially saponified polyvinyl alcohol, polyvinyl alcohol modified with various functional groups, specifically, acetoacetyl-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol,
Polyvinyl alcohols such as sulfonic acid-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol and silicon-modified polyvinyl alcohol. Acetyl-modified polyvinyl alcohol is most effective.

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, methylolmelamine, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, boric acid, alum, ammonium chloride and the like. In the protective layer, to further improve printability and sticking,
Pigments can be added as needed. Specific examples include calcium carbonate, zinc oxide, aluminum oxide,
Titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, inorganic pigments such as colloidal silica, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, raw starch Organic pigments such as particles are included.

Further, if necessary, zinc stearate,
Calcium stearate, stearic acid amide, polyethylene wax, carnauba wax, paraffin wax,
Lubricants such as ester wax, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate,
Surfactants such as alginates and fatty acid metal salts, ultraviolet absorbers such as benzophenones and triazoles, defoamers,
Various auxiliaries such as a fluorescent dye and a coloring dye may be added.

The coating amount of the protective layer is from 0.1 to
10 g / m ^2, preferably 0.5 to 5 g / m ^2,
When the amount is less than 0.1 g / m ² , the effect of solvent permeation resistance is hardly obtained, and when the amount is more than 10 g / m ² , the sensitivity may be reduced during thermal recording. The recording medium of the present invention is not only capable of simultaneous high-speed recording of ink jet recording and thermal recording, but also, if necessary, can be used for recording when an inkjet printer, a thermal printer, and each printer is used alone. is there.

[0038]

The present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is by no means restricted to these examples. In the examples, parts and% mean parts by weight and% by weight. The methods for measuring various physical properties in the examples are shown below. Example 1 1) Formation of inkjet recording layer 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 diameter of 4.3 μm manufactured by a sedimentation method 25 Part, specific surface area manufactured by sedimentation method: 290 m ² / g, average secondary particle diameter: 5.9 μm
Amorphous silica pigment (trade name: Fine Seal X-6)
0, manufactured by Tokuyama) 75 parts, 10% of silanol-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray)
250 parts of an aqueous solution and 10 parts of a polydiallyldimethylammonium chloride-based cationic resin having a molecular weight of about 100,000 (trade name: Unisense CP-103, manufactured by Senka) are added, and water is added. Liquid. Fine paper with a basis weight of 80 g / m ² and a Steckigt sizing degree of 10 seconds (SPK manufactured by Arakawa Chemical Industries as an internal sizing agent)
(Using -287) and dried using a Meyer bar so that the coating amount after drying was 10 g / m ^2, and then a super calender treatment was performed to form an ink jet recording layer.

2) Formation of Intermediate Layer Polyvinyl alcohol having an average degree of polymerization of 1050 (Kuraray)
Aqueous solution of PVA-110), the ink of the above high-quality paper.
Coating amount after drying on the opposite side of the receiving layer is 6.0 g / m ^TwoTona
And dried to form an intermediate layer. 3) Formation of heat-sensitive recording layer Preparation of dispersion A 3- (N-isopentyl-N-ethylamino) -6-meth
Chill-7-anilinofluoran 20 parts, polyvinyl alcohol
After mixing 10 parts of a 10% aqueous solution of col and 70 parts of water,
Using a sand grinder, reduce the average particle size to 1 μm or less.
Crushed. Preparation of Dispersion B 2,2-bis (4-hydroxyphenyl) propane (bi
Sphenol A) 20 parts, polyvinyl alcohol 10%
After mixing 10 parts of aqueous solution and 70 parts of water,
Pulverize until the average particle size is 1 μm or less
Was. Preparation of Dispersion C 1,2-bis (phenoxy) ethane 20 parts, polyvinyl
10 parts of 10% aqueous solution of alcohol and 70 parts of water were mixed.
Then, using a sand grinder, the average particle size is 1 μm or less.
Crushed down. Formation of heat-sensitive recording layer 50 parts of solution A, 75 parts of solution B, 75 parts of solution C, baking
30 parts of laye, 20 parts of 25% zinc stearate dispersion, 3
15 parts of 0% paraffin dispersion and 10% polyvinyl
Mix and stir 120 parts of an aqueous alcohol solution to form a coating solution.
Was. This coating solution is applied to the upper surface of the intermediate layer after drying.
5.0 g / m^TwoAfter coating and drying so that
A 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 (PVA-110, Kuraray) having an average degree of polymerization of 1050, 15 parts of kaolin (UW-90, EMC), and a 30% zinc stearate dispersion 6 parts and 30 parts of water were applied and dried on the heat-sensitive recording layer so that the applied amount after drying was 2 g / m ² , to obtain a protective layer. 5) Formation of a thermosensitive recording image The obtained recording medium was printed on a thermosensitive recording layer under the conditions of a printing voltage of 21.7 V and a printing pulse of 1.0 ms using a thermal coloration tester THPMD manufactured by Okura Electric.
A high density and clear black color image was obtained. 6) Formation of ink jet recorded image Ink jet printer PM- manufactured by Seiko Epson Corporation
Printing was performed at a recording density of 720 dpi using 700C. In Example 1, a high-density and clear color image was obtained. 7) Evaluation of blur of ink jet recorded image Ink jet printer PM- manufactured by Seiko Epson Corporation
200% density printing was performed at a recording density of 720 dpi using 700C, and the bleeding state of the adjacent portions of different colors was visually evaluated. As a result, those with little bleeding were rated A, those with some bleeding but no practical problem were rated B, and those with too much bleeding and were not practical.

8) Evaluation of fog on thermal recording layer 1 (ink penetrated fog) Ink jet printer PM- manufactured by Seiko Epson Corporation
A 200% density print was performed at a recording density of 720 dpi using 700C, and after standing for one week in an environment of 20 ° C. and 65% RH, the fogging state of the heat-sensitive recording layer was visually evaluated.
As a result, those having no fog at all were ranked A, those having some fog but having no practical problem were rated B, and those having strong fog and unpractical were rated C. 9) Evaluation of fog on thermal recording layer 2 (ink transfer fog) Inkjet printer PM- manufactured by Seiko Epson Corporation
Immediately after performing 200% density printing at a recording density of 720 dpi using 700C, two recording media were stacked such that the ink jet recording layer and the heat-sensitive recording layer were in contact with each other, and 10 g / c.
m ^{2 at} a pressure of 20 ° C and 65% RH
After standing for a week, the fogging state of the heat-sensitive recording layer was visually evaluated. As a result, A shows no fog at all, A shows slight fog but has no practical problem, and C shows strong fog and is not practical.
And ranked.

10) Evaluation of Decoloration of Thermally Recorded Image 1 (Ink Penetrating Decolorization) After forming a thermal recording image by the above method, using an ink jet printer PM-700C manufactured by Seiko Epson Corporation at a recording density of 720 dpi and 200%. Density printing was performed, and after standing in an environment of 20 ° C. and 65% RH for one week, the state of decolorization of the thermosensitive recorded image was visually evaluated. as a result,
A sample in which no decoloration was observed was ranked A, a sample in which some decoloration was recognized but no practical problem occurred was rated B, and a sample in which the decoloration was strong and was not practical was rated C. 11) Evaluation of Decolorization of Thermal Recording Image 2 (Ink Transfer Decoloring) After forming a thermal recording image by the above method, 200% density printing was performed at 720 dpi recording density using an inkjet printer PM-700C manufactured by Seiko Epson Corporation. Immediately after the operation, two recording media were overlapped so that the ink jet recording layer and the heat-sensitive recording layer were in contact with each other, and left for 1 week in an environment of 20 ° C. and 65% RH while applying a pressure of 10 g / cm ² , and the heat-sensitive recording image was obtained. Was visually evaluated for the occurrence of decolorization.
As a result, those having no decolorization were ranked A, those having some decoloration but having no practical problem were ranked B, and those having strong decoloration and not practically useful were ranked C. 12) Solvent Permeability 0.5 ml of a 10% aqueous solution of polyethylene glycol was dropped with a microsyringe on the surface to which inkjet recording suitability was imparted, and this was observed from the surface to which thermal recording suitability was imparted. The time up to the time of appearance was measured and defined as solvent permeation resistance.

Table 1 shows the results of the evaluation. Example 2 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
An aqueous solution of polyvinyl alcohol (Kuraray, PVA-117) having an average polymerization degree of 1750 was used. Table 1 shows the evaluation results. Example 3 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
Polyvinyl butyral resin (S-LEC B manufactured by Sekisui Chemical)
BM-5) An aqueous solution was used. Table 1 shows the evaluation results.

Example 4 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
Styrene-butadiene copolymer (Nip, manufactured by Nippon Zeon)
ol LX430) dispersion was used. Table 1 shows the evaluation results.
It was shown to. Example 5 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
An aqueous solution of starch (Ace A, manufactured by Oji Constarch) was used, and the coating amount was 8 g / m ² . Table 1 shows the evaluation results. Example 6 A recording medium was obtained in the same manner as in Example 1. However, no protective layer was formed. Table 1 shows the evaluation results. Example 7 A recording medium was obtained in the same manner as in Example 1. However, when forming the ink jet recording layer, the basis weight was 80 g / m ² ,
Instead of high-quality paper with a 10-second stiffness size, basis weight 1
High quality paper of 80 g / m ² , 100 seconds of Stighit sizing degree (SPK-287 manufactured by Arakawa Chemical Industries as an internal sizing agent)
Used). Further, the intermediate layer was not applied, the heat-sensitive recording layer was applied directly to the substrate, and the protective layer was not applied. Table 1 shows the evaluation results. Example 8 A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, an aqueous solution of polyvinyl alcohol (Kuraray, PVA-117) having an average degree of polymerization of 1750 was used instead of an aqueous solution of polyvinyl alcohol (Kuraray, PVA-110) having an average degree of polymerization of 1050. Table 1 shows the evaluation results. Example 9 A recording medium was obtained in the same manner as in Example 1. However, in forming the protective layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average polymerization degree of 1050, an aqueous solution of polyvinyl alcohol having an average polymerization degree of 1000 to 1500 (GOHSENOL NM-11Q manufactured by Nippon Synthetic Chemical Industry) was used. did. Table 1 shows the evaluation results. 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 (Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry) was used instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050. Table 1 shows the evaluation results. 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 (Gosefimer Z-100, manufactured by Nippon Synthetic Chemical Industry) was used instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050. 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 applied, and the heat-sensitive recording layer was applied directly to the substrate. Table 1 shows the evaluation results. Comparative Example 2 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
An aqueous solution of starch (Ace A, manufactured by Oji Constarch) was used, and the coating amount was 1 g / m ² . Table 1 shows the evaluation results. Comparative Example 3 A recording medium was obtained in the same manner as in Example 1. However, the intermediate layer was formed below the ink jet recording layer, and the coating amount was 1 g /
It was m ^2. Table 1 shows the evaluation results.

Comparative Example 4 A recording medium was obtained in the same manner as in Example 1. However, in forming the intermediate layer, instead of an aqueous solution of polyvinyl alcohol (manufactured by Kuraray, PVA-110) having an average degree of polymerization of 1050,
Polyvinyl alcohol with an average degree of polymerization of 550 (manufactured by Kuraray,
PVA-105) and the coating amount was 1 g / m ² . Further, no protective layer was formed. Table 1 shows the evaluation results. 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 Yuka Synthetic Paper) was used instead of the high quality paper having a basis weight of 80 g / m ² and a Steckigt sizing degree of 10 seconds. Table 1 shows the evaluation results.

[0047]

[Table 1]

As is clear from Table 1, the examples of the present invention were excellent in all of the bleeding, fogging and decoloring. On the other hand, Comparative Examples 1, 2, 3, and 4 have low solvent permeation resistance, causing fogging and decoloring. Further, Comparative Example 5 has high solvent resistance and does not cause fogging or decoloration, but the blurring of the ink jet recorded image is remarkable and is not practical. That is, the recording medium of the present invention has excellent inkjet recording suitability and heat-sensitive recording suitability without causing any bleeding, fogging, or decoloring. In the evaluation of the solvent permeation resistance in Table 1, the solvent using the synthetic paper of Comparative Example 5 did not penetrate to the back surface in the case of 60 seconds. In the other examples using the paper base material, the values were 60 seconds or more and 1000 seconds or less.

[0049]

According to the present invention, high-speed double-sided recording is possible, and
At least one side was suitable for color inkjet recording, and one side was a recording medium capable of thermal recording. A double-sided recording medium for heat-sensitive recording and ink-jet recording, in which bleeding does not occur on the ink-jet recording surface, the solvent in the ink-jet ink does not cause fogging of the heat-sensitive recording layer, and the printing on the heat-sensitive recording layer does not disappear. Met.

Claims (5)

[Claims] 1. A double-sided recording medium comprising a pulp-based paper base material provided with ink jet recording aptitude on one side and a heat-sensitive recording layer provided on the other side, and a micro-syringe applied to the surface having an ink jet recording aptitude. A double-sided recording medium wherein the time required for dropping 0.5 ml of a 10% aqueous solution of polyethylene glycol and permeating the surface of the heat-sensitive recording layer is 30 seconds or more. 2. The double-sided recording medium according to claim 1, wherein an intermediate layer containing a resin is provided between the paper substrate and the heat-sensitive recording layer. 3. The resin of the intermediate layer is a polyvinyl butyral resin, a styrene-butadiene copolymer, and has an average degree of polymerization of 800.
3. The double-sided recording medium according to claim 2, comprising at least one of the above polyvinyl alcohols. 4. The double-sided recording medium according to claim 1, wherein a protective layer containing a resin is provided on the heat-sensitive recording layer. 5. The double-sided recording medium according to claim 4, 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.