JP2001180105A - Manufacturing method of recording medium employing amphoteric polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a recording medium employing an amphoteric polymer. SOLUTION: The recording medium constituted of at least a substrate and a coating layer provided on the substrate can be manufactured by a method wherein coating liquid, containing at least a polymer, showing hydrophilic property at a temperature lower than a transition temperature, and hydrophobic property at a temperature higher than the transition temperature reversibly while capable of forming the coating layer, is prepared and is applied on the substrate at a temperature lower than the transition temperature, then, the substrate is heated at a temperature higher than the transition temperature thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a recording medium used for printing.

[0002] Currently, as a method for producing the recording medium, various production methods such as by uniformly coated or impregnated with the coating solution in a two-dimensional sheet-like medium is present. Generally, a recording medium is manufactured by appropriately selecting a sheet-like medium, a processing device, and a coating liquid according to the purpose and use of the recording medium. Usually, when a liquid is applied to a sheet-like medium, a compound to be applied is dispersed or dissolved in an appropriate solvent to be liquefied to form a coating liquid, and the coating liquid is applied to a sheet-like medium using a processing device. After coating, a method of removing the solvent is used. As a method for removing the solvent after coating, a heat removal method is extremely common, and is used, for example, in a method for producing art paper and coated paper. On the other hand, recently, there has been an increasing tendency to protect the global environment, and there has been a demand for solvents used in the production of recording media that have excellent environmental safety. For this reason, water is used as a solvent which is rich in environmental safety, inexpensive in production cost, and frequently used.

[0003] Further, when producing a printing recording medium, it is necessary to remove the solvent after applying the coating liquid to the sheet-shaped medium, and this drying step is often rate-limiting. This is because, after applying an appropriate amount of coating liquid to a sheet-like medium, it is necessary to raise the drying temperature in order to increase the speed of the production line and efficiently produce a large amount in a short time. On the other hand, this is due to the contradiction that raising the drying temperature increases energy costs. In particular, when water is used as a solvent, efficient production is difficult unless the drying temperature is set to a boiling point (100 ° C.) or higher.

In order to solve such a problem, it is a general solution to increase the concentration of the compound in the coating solution to shorten the drying time and increase the speed of the production line. But,
It may be difficult to increase the concentration of the coating liquid depending on the type of the compound to be coated on the sheet medium. Also,
When the concentration of the coating liquid is increased, the viscosity also increases, and as a result, it may be difficult to apply the coating liquid uniformly to the sheet medium. Therefore, there arises a problem that the coated surface of the recording medium cannot be sufficiently secured. Further, when the sheet-like medium is heat-meltable such as a thermoplastic polymer, there is a risk that the sheet-like medium is softened and melted due to an increase in the drying temperature.
Therefore, at present, in order to efficiently manufacture a recording medium, know-how and a skilled technique for appropriately selecting and adjusting a sheet-like medium, a coating liquid, a coating method, a processing apparatus, and a processing method are important. Element. In particular, when applying a low-concentration coating liquid to a sheet-like medium, such know-how elements are required.

[0005] Further, when the selection of the sheet-shaped medium is functionally restricted, the types of compounds constituting the coating liquid and the physical properties such as the concentration and viscosity of the coating liquid are also restricted. for that reason,
In order to manufacture recording media with various uses and functions, it is often necessary to change coating equipment and production lines. As a result, processing manufacturers need to prepare many types of coating equipment. This is the situation at present.

[0006]

SUMMARY OF THE INVENTION The present inventors have now used a method for producing a recording medium, which uses a coating liquid to which a polymer is added which is reversibly hydrophilic below the transition temperature and hydrophobic above the transition temperature. Thus, it has been found that the drying step can be simplified and inexpensive, and that a recording medium suitable for various purposes can be manufactured in a short time and at low cost. The present invention is based on this finding.

That is, according to the present invention, when the temperature exceeds a certain temperature at the time of drying and heating, the polymer exhibits hydrophobicity and releases water, and the polymer having hydrophilicity is again added to the coating liquid by cooling to a temperature lower than the temperature. Accordingly, it is an object of the present invention to provide a method for manufacturing a recording medium, which improves drying efficiency and is preferable from the viewpoint of manufacturing cost.

The production method according to the present invention is a method for producing a recording medium comprising at least a substrate and a coating layer provided thereon, wherein the recording medium is reversibly hydrophilic at a transition temperature or lower. Shows at least a transition temperature or higher at least contains a polymer exhibiting hydrophobicity, and prepares a coating solution capable of forming a coating layer, the coating solution, on the substrate at a temperature below the transition temperature Coating and then heating the substrate at a temperature above the transition temperature.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Manufacturing method of recording medium The manufacturing method in the present invention is basically a polymer which reversibly exhibits hydrophilicity below the transition temperature and shows hydrophobicity above the transition temperature (hereinafter referred to as amphoteric polymer). And a component forming a coating layer is provided at least, and the coating liquid is applied to a substrate, and then the substrate is heated to a temperature equal to or higher than the transition temperature of the amphoteric polymer. And heating.

In the production method according to the present invention, by using a coating liquid containing an amphoteric polymer, the drying time can be shortened and the heat energy for drying can be greatly reduced. It can be said that it is an unexpected fact that a recording medium adapted to various uses can be manufactured without using a know-how element and a dedicated processing device. In particular, the production method of the present invention has a remarkable effect in producing a recording medium for ink jet recording which is usually produced using a coating liquid having a low concentration.

Preparation of Coating Liquid In the production method according to the present invention, a coating liquid is used. The coating liquid is
Basically, it comprises at least a polymer that reversibly exhibits hydrophilicity below the transition temperature and exhibits hydrophobicity above the transition temperature, and a component forming the coating layer. Amphoteric polymer The ink receiving component according to the present invention comprises at least an amphoteric polymer and water. The amphoteric polymer used in the present invention is a polymer capable of reversibly exhibiting a hydrophilic property at a transition temperature or lower and a hydrophobic property at a transition temperature or higher. In the present invention, the temperature at which the property of the amphoteric polymer changes at a specific temperature is called "transition temperature".

The amphoteric polymer according to the present invention can be prepared by introducing a hydrophobic group and a hydrophilic group into an existing polymer, polymerizing a monomer having a hydrophobic group with a monomer having a hydrophilic group, or And a monomer having a hydrophilic group. Preferably, an amphoteric polymer obtained by polymerizing a monomer having a hydrophobic group and a hydrophilic group is preferable. Since the transition temperature of the amphoteric polymer differs depending on the type of monomer,
The desired transition temperature can be arbitrarily selected by freely selecting the kind and ratio of the monomers.

Specific examples of monomers for producing the amphoteric polymer include NN-diethylacrylamide, N
-Isopropylacrylamide, N-ethylacrylamide, N-cyclopropylacrylamide, N-ethylmethylacrylamide, N-propylethylacrylnoleamide, N-propylacrylamide, N-isopropylmethylacrylamide, N-cyclopropylmethylacrylamide, N-methyl -N-ethylacrylamide, N-methyl-N-isopropylacrylamide, N
And one or more monomers selected from the group consisting of -methyl-NN-propylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, and N-methoxyacrylamide.

[0014] Further, it comprises one or more of the monomers represented by the following formula (I), or comprises a monomer represented by the following formula (I) and another ethylenically unsaturated monomer: Can be used. This polymer is disclosed and known in Japanese Patent Publication No. 23375/1994.

Embedded image [Wherein R ¹ represents hydrogen or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms or a phenyl group,
n represents an integer of 2 to 50, preferably 2 to 30]

Specific examples of the monomer represented by the formula (I) include methoxy (poly) ethylene glycol monoacrylate, methoxy (poly) ethylene glycol monomethacrylate, ethoxy (poly) ethylene glycol monoacrylate, ethoxy (poly) ethylene Glycol monomethacrylate, n-propyl (poly) ethylene glycol monoacrylate, n-propyl (poly) ethylene glycol monomethacrylate, isopropyl (poly) ethylene glycol monoacrylate, isopropyl (poly) ethylene glycol monomethacrylate, n
-Butyl (poly) ethylene glycol monoacrylate, n-butyl (poly) ethylene glycol monomethacrylate, isobutyl (poly) ethylene glycol monoacrylate, isobutyl (poly) ethylene glycol monomethacrylate, t-butyl (poly) ethylene glycol monoacrylate , T-butyl (poly) ethylene glycol monomethacrylate, phenoxy (poly) ethylene glycol monoacrylate, phenoxy (poly)
Examples include ethylene glycol monomethacrylate.

Specific examples of other copolymerizable ethylenically unsaturated monomers include alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate, and styrene, and more preferably,
And acrylic acid alkyl esters. These monomers can be used as one kind or as a mixture of two or more kinds.

The amphoteric polymer used in the present invention can be produced by heating one or more of the above monomers under degassing under reduced pressure. As the polymerization method, known methods such as solution polymerization, emulsification, suspension, and bulk polymerization of the above monomers in the presence of a radical polymerization catalyst, ionic polymerization, and photopolymerization can be used. The average molecule of the amphoteric polymer is not particularly limited, but is 10 ³ to 10 ⁶
Range, preferably in the range of 10 ⁴ to 10 ⁵ .

The transition temperature of the amphoteric polymer in the present invention is preferably in the range of about 25 ° C. to 120 ° C., more preferably in the range of about 40 ° C. to 70 ° C. In the present invention, the transition temperature can be appropriately selected depending on the production method and the recording medium to be produced. The transition temperature of the amphoteric polymer can be appropriately changed by selecting a monomer. For example, when NN diethylacrylamide or N-isopropylacrylamide is used as a monomer, it is the most preferred monomer since the transition temperature is about 40 ° C. and the temperature-sensitive speed is high.

The amount of the amphoteric polymer to be added can be appropriately determined depending on the type of the coating solution. When the coating solution is aqueous, the amount of the amphoteric polymer is 0.1% by weight based on the total water weight in the coating solution. % To less than 10% by weight, more preferably about 1% to less than 8% by weight. When the amount is 0.1% by weight or more, the effect of adding the amphoteric polymer can be sufficiently exhibited. 10% added
By being less than 1, rapid dehydration due to heating can be prevented, and as a result, it is possible to produce a target recording medium without generating cracks, bubbles, and irregularities on the coated surface after drying. .

The production method of the present invention is used for a method of coating a substrate with an aqueous coating liquid to which the amphoteric monomer described above can be added. And the amphoteric polymer is not determined by the form and properties of the coating liquid components, coating device, impregnating device, and heating / drying device. Can also be suitably used. Further, in the production method of the present invention, it is possible to produce a recording medium using a coating liquid other than an aqueous coating liquid. In this case, a recording medium can be manufactured by using an amphoteric polymer that can be dissolved in a solvent other than an aqueous solvent and has a transition temperature below the boiling point of the solvent. In this regard, those skilled in the art will easily understand.

Coating Layer Forming Component and Other Optional Components The coating solution according to the present invention further comprises a coating layer forming component,
And, if necessary, other optional components.
Coating layer components can be added in accordance with the recording medium produced by the production method according to the present invention. For example, in the case of aqueous coating liquids used for processing various coated papers, synthetic papers, processed films, adhesive films, nonwoven fabrics, etc., a coating layer forming component adapted to these papers is used as a coating liquid. It is possible to add. For example, art paper, coated paper, measurement coated paper, in the coated paper represented by lightly coated paper, the amphoteric polymer in the present invention, a white pigment, a binder,
A coating liquid may be prepared by adding an auxiliary agent.

The coating liquid according to the present invention includes white pigments represented by silica gel, alumina sol (including pseudo-boehmite), clay, kaolin, kaolin clay, hydrated alumina, talc, calcium carbonate, titanium dioxide;
Colored pigments represented by magenta and cyan; acrylic resins, polyester resins, polyurethane resins, styrene-
Butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl alcohol resin, water-soluble polyvinyl acetal resin, polyvinyl butyral resin, other vinyl resins, amide resins, starch oxide, casein, polyethylene oxide, polyvinyl pyrrolidone,
Binders represented by water-soluble resins and aqueous emulsion resins such as silicone resins, rosin-modified maleic resins, rosin-modified phenol resins, alkyd resins, and cumarone-indene resins; starch, modified starch, carboxymethyl cellulose, polyvinyl alcohol, poly Dry strength additive represented by acrylamide; creping agent represented by aminopolyamide-epichlorohydrin resin; retention improver represented by starch, carboxymethylcellulose, polyacrylamide, silicone emulsion, higher alcohol and derivatives thereof Representative antifoaming agents; flocculants; anti-warpage agents and the like can be added.

According to a preferred embodiment of the present invention, when the recording medium to be produced is for ink jet recording, an ink receiving layer forming component may be added to the coating liquid in some cases. The ink-receiving layer forming component is composed of a so-called water-soluble resin, and includes a component that absorbs and swells the ink composition to form an image, or includes fine particles, and the fine particles themselves adsorb the colorant in the ink composition. Alternatively, it may be any of those which form an image by holding in the gap between fine particles. Further, in the recording medium according to the present invention, the ink receiving layer forming component may be transparent or substantially opaque.

According to a preferred embodiment of the present invention, when the ink-receiving layer forming component is composed of a water-soluble resin, examples of the preferable water-soluble resin include polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose and the like. Cellulose resins, polyvinylpyrrolidone, starch, casein, gelatin, polyacrylamide, styrene-butadiene copolymer latex, carboxyl-modified styrene-butadiene copolymer latex, acrylic emulsion, and the like.

When the ink-receiving layer-forming component contains fine particles, the ink-receiving layer-forming component is preferably formed basically of a pigment and a binder as main components. Here, examples of the pigment include silica, alumina sol (including pseudo-boehmite), clay, mica, swellable mica, talc, kaolin, diatomaceous earth, calcium carbonate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, Examples include white pigments such as lithopone and satin white, and organic or inorganic coloring pigments.
As the binder, for example, acrylic resin, polyester resin, polyurethane resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl alcohol resin, water-soluble polyvinyl acetal resin, polyvinyl butyral resin, and others Water-soluble resins and aqueous emulsions such as vinyl resins, amide resins, oxidized starch, casein, polyethylene oxide, polyvinylpyrrolidone, silicone resins, rosin-modified maleic resin, rosin-modified phenol resin, alkyd resin, and cumarone-indene resin Resins.

The components for forming the ink receiving layer according to the present invention include:
Other components that improve the properties of the recording medium may be added.
For example, a water-resistant agent such as a melamine formaldehyde resin, a urea formaldehyde resin, an acrylamide-based resin, glyoxal, or ammonium zirconium carbonate may be added to improve the water resistance of the ink receiving layer and impart a function of preventing ink bleeding. Further, a light stabilizer (for example, a hindered amine light stabilizer), an antioxidant, a quencher, and the like may be added. Further, in order to further improve the productivity, recording characteristics, or storage stability of the inkjet recording paper, a dispersant, a fluorescent dye, a pH adjuster,
Antifoaming agents, wetting agents, preservatives, ultraviolet absorbers and the like may be added.

Substrate The recording medium according to the present invention is formed based on a substrate.
The substrate of the recording medium according to the present invention is not particularly limited as long as it can support the ink receiving layer or the gloss layer and has the strength as the recording medium, and may be either transparent or opaque. Examples of the opaque substrate include cloth, wood, metal plate, paper, and the like. Further, a opaque substrate obtained by subjecting a later-described transparent substrate to opacity treatment can also be used.

In the present invention, paper is preferably used as the base material. The paper is preferably made of pulp raw material mainly composed of natural cellulose fibers, and its composition and production method may be appropriately determined. For example, paper produced by a wet papermaking method is preferably used. Specifically, coniferous wood as a pulp raw material, wood pulp such as kraft pulp, which is produced by blending hardwood alone or appropriately, sulfite pulp, semi-chemical pulp, etc. are used, and bleached pulp is preferable for obtaining clear printing. . It is also possible to use non-wood pulp such as waste paper pulp, pagasu, kenaf, cotton, hemp, esparto, bamboo and straw.

Further, in papermaking, a sizing agent, a wet paper strength agent, a filler, and a surface paper strength enhancer may be appropriately blended as internal additives. In addition, starch, modified starch, carboxymethylcellulose, as additive chemicals for internal addition to pulp raw materials,
Internal paper strength agents such as polyacrylamide and styrene resin,
Coloring agents, fixing agents such as sulfuric acid bands and polyacrylamide,
Furthermore, in addition to the surface paper strength enhancer described later as a coating chemical, a water-resistant agent such as dialdehyde starch, melamine resin, polyamide resin, an antistatic agent, a water repellent, a friction agent, a surface sizing agent, a pigment, etc. are required. Can be used accordingly.

When a transparent base material is selected as the base material of the recording medium according to the present invention, examples thereof include polyester resin, diacetate resin, triacetate resin, and the like.
Acrylic resins, polycarbonate resins, polyvinyl chloride resins, polyimide resins, films or plates of cellophane, celluloid, etc., glass plates and the like can be mentioned. According to a preferred embodiment of the present invention, when the substrate is transparent, a polyester film is preferable, and particularly preferably a biaxially stretched polyethylene terephthalate film on which corona treatment is performed on one or both sides is uniform without coating unevenness. It is preferable because coatability is obtained and good adhesion between the ink receiving layer and the substrate is obtained. Furthermore, it is also possible to use a polyethylene film containing a white inorganic pigment or whitened by containing fine bubbles inside the film as a base material.

The thickness of the base material may be appropriately determined according to the use of the paper, but is generally preferably in the range of about 50 to 250 μm, and more preferably in the range of about 75 to 200 μm. However, it is not limited to these ranges.

Means for Applying Coating Liquid to Substrate and Heating
Means The production method according to the present invention has means for applying a coating solution to a substrate at a temperature equal to or lower than the coating temperature. As a means for coating the substrate, a coating solution is applied to the substrate at a temperature not higher than the transition temperature of the amphoteric polymer by a conventional method (including coating, impregnation, immersion, etc.). Preferably, the coating liquid is applied by a coating machine having a coater head. The coater head can be appropriately selected according to the coating liquid, the base material, and the recording medium to be manufactured. As the coater head, blade coater,
Examples include an air knife coater, a gravure coater, a transfer roll coater (such as a KCM coater and a gate roll coater), a lot coater, a bar coater, a hydro bar coater, a die coater, a bead coater, and a curtain coater.

The production method in the present invention comprises applying a coating solution to a substrate at a temperature lower than the transition temperature and then heating the substrate at a temperature higher than the transition temperature. Can be done with Further, the temperature management can be controlled using a control device.

According to a preferred embodiment of the present invention, the production method of the present invention may be used as a step subsequent to a papermaking step for preparing a substrate. Therefore, according to another aspect of the present invention, the production method according to the present invention can be used as one aspect of a series of papermaking steps from the step of dispensing a base material to the production of a recording medium.

Manufacturing Apparatus According to another preferred embodiment of the present invention, it is possible to provide a manufacturing apparatus for performing the manufacturing method according to the present invention. The production apparatus according to the present invention comprises a coating liquid capable of forming a coating layer, comprising at least a polymer that exhibits a hydrophilic property at a reversible temperature below the transition temperature and a hydrophobic property at a temperature above the transition temperature,
It can be carried out using a manufacturing apparatus comprising means for applying the base material at a temperature equal to or lower than the transition temperature, and means for heating the base material at a temperature equal to or higher than the transition temperature.
Preferred examples of such a manufacturing apparatus include a coater head as a means for coating a base material, a dryer as a means for drying the base material, a winder as a means for finishing a recording medium, and a control device. Is preferred.

Use of the manufactured recording medium In the manufacturing method according to the present invention, the recording medium is used in a recording system using an ink composition. Examples of the recording method using the ink composition include an ink jet recording method, a recording method using a writing instrument such as a pen, and various other printing methods. In particular, the recording medium according to the present invention is preferably used in an ink jet recording method in which droplets of an ink composition are ejected, and the droplets are attached to the recording medium to perform printing.

EXAMPLES The following examples are disclosed in order to clarify the content of the present invention, but the scope of the present invention is not interpreted by limiting the scope of the examples.

Preparation of Substrate 20 parts by weight of NBKP (bleached kraft pulp of N-wood (coniferous)) and 80 parts by weight of LBKP (bleached kraft pulp of L-wood (hardwood)) were mixed for 500 m.
1C. S. F beaten. The beating machine used a PFI mill of Kumagai. 10 parts by weight of clay, 0.3 parts by weight of paper strength agent (trade name "Polystron" manufactured by Arakawa Chemical Industries), and 2 parts by weight of sizing agent ("Size Pine E" manufactured by Arakawa Chemical Industries) And 2 parts by weight of a sulfuric acid band. The preparation (paper) was introduced into a fourdrinier paper machine to prepare a base material having a basis weight of 110 g / m ² by a conventional method.

The N, N 'diethylacrylamide polymer used in the preparation example of the amphoteric polymer was prepared by the following procedure. N, N 'diethylacrylamide monomer (produced by Kojin Co., Ltd.) was prepared using water as a solvent to a concentration of 2.5 mol / L. Then, azobisisobutyronitrile (A
IBN) was added as a polymerization initiator, and a polymerization reaction was carried out at a temperature of 50 ° C. to obtain a polymer. Before and during the reaction, the preparation was subjected to bubbling displacement with nitrogen gas of sufficiently high purity. The transition temperature of the obtained N, N ′ diethylacrylamide polymer was 32 ° C. The transition temperature was measured by measuring the N, N 'diethylacrylamide polymer in 5
% Aqueous solution, which was placed in a test tube, gradually heated, and the temperature at the cloudy point was measured.

Preparation Example 1 of Coating Liquid A coating liquid for art paper for offset printing was prepared according to the following composition (solid content: 60%). UW-90 (kaolin) 70 parts by weight FMT-90 (calcium carbonate, manufactured by FMT) 30 parts by weight MS4600 (modified starch, manufactured by Nippon Shokuhin Kako Co., Ltd.) 5 parts by weight po1y1ac750 13 parts by weight (SBR latex, manufactured by Mitsui Chemicals, Inc.) Baycoat 20 (coating waterproofing agent, manufactured by Nippon Light Metal Co., Ltd.) 0.5 parts by weight N, N'-diethylacrylamide polymer 5 parts by weight

Example 2 A coating liquid for a recording medium for ink jet recording was prepared according to the following composition (solid content: 22%). P78D (silica gel, manufactured by Mizusawa Chemical Co., Ltd.) 100 parts by weight PVA117 40 parts by weight (polyvinyl alcohol, manufactured by Kuraray Co., Ltd.) Sumireze resin 1001 15 parts by weight (ink fixing agent, manufactured by Sumitomo Chemical Co., Ltd.) N, N′-diethylacrylamide polymer 5 Parts by weight

Comparative Example 1 A resin was prepared by the same composition as that shown in Example 1 except that no N, N'-diethylacrylamide polymer was added.

Comparative Example 2 A composition was prepared according to the same composition as shown in Example 2, except that no N, N'-diethylacrylamide polymer was added.

[0043]Recording media evaluation test Evaluation 1: Dehydration test Bar Coater with Coating Solution According to Example 1 or Comparative Example 2 on Base Material
15g / m ²And then apply 1
The moisture content when dried with a dryer at 20 ° C. is measured over time.
A dehydration test was performed. The results are shown in Table 1 below.
It was as expected.

Table 1 Time (sec) / 0 5 10 15 20 30 45 60 Moisture percentage (%) Example 1 29.2 25.5 12.2 10.8 6.5 4.5 3.3-Comparative example 1 29.3 25.5 20.8 15.5 10.5 8.8 5.8 3.1 Example 2 62.2 59.2 45.5 30.0 20.2 15.1 10.2 7.8 Comparison Example 2 62.1 60.8 52.2 48.7 34.7 24.3 18.2 12.6

Evaluation 2: Suitability test for offset printing Offset printing was performed on the recording medium coated with the coating liquid of Example 1 and Comparative Example 2 after drying. Using an RI tester (manufactured by Ishikawajima Sangyo Kikai Co., Ltd.), the following evaluation was performed. Evaluation 2-1: Transfer offset printing was performed at a rotation speed of 80 rpm under an ink weight of 0.3 cc by using a color density high echo MZ cyan (manufactured by Toyo Ink Co., Ltd.) as an ink. End of printing 1
The color density after a day was measured with a spectrophotometer SPM50 (trade name, manufactured by Daletag Macbeth). The measurement conditions were light source D
50, without a light source filter, the white standard was absolute white, and the viewing angle was 2 °. The results were as shown in Table 2 below. Evaluation 2-2: Printing was performed under the same conditions as in the above color density measurement using surface strength ink tack 15 (manufactured by Toyo Ink Co., Ltd.) as an ink for strength measurement. The surface strength after printing was visually evaluated according to the following evaluation criteria. The results were as shown in Table 2 below. Evaluation A: Strength was sufficient. Evaluation B: The strength was not sufficient, but was of a level that could withstand a recording medium. Evaluation C: Trapping occurred and strength was insufficient. Evaluation 2-3: Quick-drying The recording medium was printed as a test paper of 15 cm × 15 cm under the same conditions as in the measurement of color density. Immediately after printing is finished, high quality paper (trade name: Mashomaro, weighing 128 g / m2)
2; Oji Paper Co., Ltd.) on the printing surface and 1 kg / c
m ² and left for 15 minutes. The degree of show-through of the ink after standing was visually evaluated according to the following evaluation criteria. The results were as shown in Table 2 below.
Evaluation A: There was no show-through and the quick-drying property was excellent. Evaluation B:
Some show-through was seen, and it was of a limit that could be used. Evaluation C: The show-through was intense and was not dried.

Table 2 Examples / Evaluation 2-1 2-2 2-3 Examples 1 1.75 A A Comparative Example 1 1.75 A A

Evaluation 3: Inkjet printing evaluation test A printing evaluation test was performed on the recording medium coated with the coating liquid of Example 2 after drying and Comparative Example 2. Using an inkjet printer PM800C (manufactured by Seiko Epson Corporation), a standard color ink (black, magenta, cyan, yellow: the standard ink composition of the printer) was inkjet-recorded on the above two types of recording media and printed. Was evaluated.

Evaluation 3-1: The black ink composition, the magenta ink composition, the cyan ink composition, and the yellow ink composition were each solid-printed on a recording medium (100% d) by the printer.
uty) performed. The reflection density of the printing area of each color was measured using a spectrophotometer SPM50 (trade name, manufactured by Daletag Macbeth). The measurement conditions were as follows: light source D50, no light source filter, white standard was absolute white, and viewing angle was 2 °.
The results were as shown in Table 3 below.

Evaluation 3-2: Any two colors were selected from the group consisting of an ink-absorbing black ink composition, a magenta ink composition, a cyan ink composition, and a yellow ink composition, and each was 100%. One by one,
An image was formed by performing mixed-color printing by outputting a total of 200% of the ink composition. The obtained images were visually evaluated according to the following criteria. The results were as shown in Table 3 below. Evaluation A: Both colors were absorbed by the recording medium, did not bleed, and there was no set-off after output. Evaluation B: Both colors were absorbed by the recording medium without bleeding, but set-off occurred when a pressure of 1 g / cm ² was applied after output. Evaluation C: Both colors were absorbed by the recording medium, slight bleeding was observed, and they were set off when allowed to stand, but were within a practically acceptable range. Evaluation D: The ink overflowed from the recording medium and was not practically acceptable.

Evaluation 3-3: The water-resistant black ink composition, the magenta ink composition, the cyan ink composition, and the yellow ink composition were each solid printed (100% d) on a recording medium by the printer.
util). A drop of 0.1 g of water was dropped on the solid printing area, and left at 20 ° C., 50% RH for 24 hours. The bleeding of the ink in the obtained print area was visually evaluated according to the following criteria. The results were as shown in Table 3 below. Evaluation A: No bleeding was observed. Evaluation B: Almost no bleeding. Evaluation C: Although slightly blurred, it was within a practically acceptable range. Evaluation D: Bleeding was observed, which was unacceptable for practical use.

Evaluation 3-4: The light-resistant black ink composition, the magenta ink composition, the cyan ink composition, and the yellow ink composition were each adjusted to have a reflection density of 1.0 on a recording medium by the above-mentioned printer. Printing was done. The print was then exposed as described below. Light irradiation is Xenon weatherometer Ci3
5A (manufactured by ATLAS) was used. Irradiation is performed at a black panel temperature of 63 ° C. and a relative humidity of 50% at 340 nm.
UV light, emissivity 0.25 W / m ² , irradiation condition 45 kJ /
It was m ^2. After the irradiation, the reflection density of the printed matter was measured using a spectrophotometer SPM50 (trade name, manufactured by Dartag Macbeth). The measurement conditions were as follows: the light source D50, no light source filter, the white standard was absolute white, and the viewing angle was 2 °. The evaluation results were as shown in Table 3 below. Evaluation A: Exceeded 90%. Evaluation B: 80 or more and less than 90%. Evaluation C: Less than 80%.

Table 3 Examples / Evaluation 3-1 3-2 3-3 3-4 Example 2 1.62 A AB Comparative Example 2 1.64 A AB

From the results shown in Tables 1 to 3, according to the production method of the present invention, since a coating liquid using an amphoteric polymer having a transition temperature is used, the drying time can be reduced in the production of a recording medium. As a result, a low-cost and energy-efficient recording medium can be manufactured. Also, it can be seen that there is no difference between the recording medium manufactured by the manufacturing method according to the present invention and the recording medium manufactured without adding the amphoteric polymer according to the present invention.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) D21H 27/00 B41J 3/04 101Y F-term (Reference) 2C056 FC06 2H086 BA02 BA15 BA33 BA34 4D075 BB21X BB21Z BB93X BB93Z CA35 DA04 DB18 DC27 EA06 EA35 EB22 EB39 EB53 EB56 EC11 4L055 AG71 AG73 BE08 EA20 FA15 GA09

Claims (15)

[Claims] 1. A method for producing a recording medium comprising at least a substrate and a coating layer provided thereon, wherein the recording medium is reversibly hydrophilic at a transition temperature or lower and hydrophobic at a transition temperature or higher. A coating liquid comprising at least a polymer having a water-soluble property and capable of forming a coating layer is prepared, and the coating liquid is applied to a substrate at a temperature equal to or lower than the transition temperature. A method of manufacturing, comprising heating the material at a temperature above the transition temperature. 2. The recording medium according to claim 1, wherein the transition temperature of the polymer is from 15 to 120 ° C. 3. The polymer according to claim 1, wherein the polymer is N-N-diethylacrylamide, N-isopropylacrylamide, N-ethylacrylamide, N-cyclopropylacrylamide,
-Ethylmethylacrylamide, N-propylethylacrylanolamide, N-propylacrylamide, N-isopropylmethylacrylamide, N-cyclopropylmethylacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N-isopropylacrylamide, N -Methyl-NN-propylacrylamide, N
3. The method according to claim 1, wherein the method comprises one or two or more monomers selected from the group consisting of -acryloylpyrrolidine, N-acryloylpiperidine, and N-methoxyacrylamide. 4. 4. The polymer comprises one or more monomers represented by the following formula (I), or comprises a monomer represented by the following formula (I) and another ethylenically unsaturated monomer: The method according to claim 1, wherein the method comprises: Embedded image [Wherein, R ¹ represents hydrogen or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and n represents an integer of 2 to 50] 5. The method according to claim 1, wherein the ethylenically unsaturated monomer is one or a mixture of two or more selected from the group consisting of alkyl acrylates, alkyl methacrylates, acrylonitrile, vinyl acetate, and styrene. The production method according to any one of the above. 6. The production method according to claim 5, wherein the amount of the amphoteric polymer added is 0.1% by weight or more and less than 10% by weight based on the total water weight in the coating solution. 7. The production method according to claim 1, wherein the coating liquid contains a component for forming an ink receiving layer. 8. The method according to claim 7, wherein the ink-receiving layer forming component comprises a pigment and a binder. 9. The method according to claim 1, wherein the substrate is paper. 10. A recording medium manufactured by the manufacturing method according to claim 1. 11. A recording method for printing on a recording medium by adhering an ink composition, wherein the recording medium is used.
A recording method using the recording medium according to 1. 12. The recording method according to claim 11, wherein the recording method is an ink jet recording method. 13. The recording method according to claim 10, wherein the ink jet recording method is a method in which droplets of the ink composition are ejected, and the droplets are attached to a recording medium to perform printing. 14. A printed matter printed by the recording method according to any one of claims 11 to 13. 15. A production apparatus for carrying out the production method according to any one of claims 1 to 9, which reversibly shows hydrophilicity below the transition temperature and shows hydrophobicity above the transition temperature. Means for applying a coating liquid comprising at least a polymer and capable of forming a coating layer to the substrate at a temperature equal to or lower than the transition temperature, and heating the substrate at a temperature equal to or higher than the transition temperature Manufacturing means.