JP3321318B2 - Manufacturing method of receiving paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image receiving paper for various printers such as a hot-melt type printer, a thermal sublimation type printer and an ink jet printer, as well as a label image receiving sheet and a printing plastic sheet. The present invention relates to a method for manufacturing an image receiving paper having a wide range of application purposes, which can be used for paper and the like.

[0002]

2. Description of the Related Art In a hot-melt printer, high quality paper has been widely used as an image receiving paper. However, with higher image quality,
In order to improve the fixability of small dots by smoothing the surface, and in recent years, in particular, as a high-definition full-color printer, a system that can obtain extremely high gradation using a variable dot size thermal head has been adopted, In order to reproduce dots, a method has been proposed in which a porous layer is provided on the surface of an image receiving paper to improve ink absorbency and transferability.

For example, in Japanese Patent Application Laid-Open No. 62-79237, a polyamide resin or a polyurethane resin is dissolved in a hydrophilic organic solvent together with other additives, and this coating solution is applied to the surface of a support to form a film by a wet method. It has been proposed to form an image receiving layer having excellent ink absorbability. Further, JP-A-62-197183 discloses that a single or copolymer of vinyl chloride and a single or copolymer of acrylonitrile having poor compatibility with vinyl chloride are used, and they are dissolved in a solvent to form a solution on a substrate. A method has been proposed in which, after coating on a surface, a solution in which the solvent is dissolved but the plastic is not dissolved is coagulated and dried to produce a surface-porous plastic sheet.

Further, Japanese Patent Application Laid-Open No. 2-41287 discloses a method for producing a thermal transfer printer image receiving sheet having excellent gloss by smoothing the surface of a plastic sheet obtained in Japanese Patent Application Laid-Open No. 62-197183. A way to do that has been proposed. JP-A-6-171250 discloses that an ink image-receiving layer containing a binder resin such as styrene-butadiene latex and a pigment as a main component is formed on a sheet-like support. A method has been proposed in which a solid plasticizer is contained in advance, and then the ink image-receiving layer is immersed in a solvent of the solid plasticizer to elute the solid plasticizer to obtain a porous image-receiving sheet. ing.

Also, in a thermal sublimation printer, the formation of a cushion layer on an image-receiving paper improves the area of the thermal head, and utilizes the heat storage property of the thermal head by the porous layer to increase the recording density. Various methods for obtaining printed matter have been proposed. Also, a method has been proposed for an ink jet printer in which the image receiving paper is made porous to improve the ink absorbency.

[0006]

According to these proposals, a certain improvement in dot reproducibility and recording density can be recognized. However, it is still insufficient to obtain a high gradation property comparable to that of a thermal sublimation printer using a hot-melt printer. For example, when an extremely small dot having a diameter of 50 μm or less is formed, there is a problem in dot reproducibility. Further, none of the printer receiving papers has been sufficiently satisfactory in terms of recording density.

The present invention solves the above-mentioned disadvantages of the prior art,
It is an object of the present invention to provide an image receiving paper having good ink fixing property and excellent dot reproducibility, especially high dot reproducibility. Another object of the present invention is to provide various types of receiving paper for printers, label receiving paper, and plastic raw materials for printing, as a receiving paper from which a good printed matter having a high recording density can be obtained.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, provided a polymer porous layer having a specific pore structure as an ink image receiving layer on the surface of a substrate. By forming the polymer porous layer by a specific method, it has been found that an image receiving paper having excellent reproducibility of high-definition dots and capable of improving the recording density can be obtained, thereby completing the present invention. It has led to.

[0009] That is, the present invention provides a method for forming a highly
Apply the solvent solution of the parent material in a thin film
Coagulation that is compatible with the solvent of the solution but does not dissolve the polymer material
By contacting the solvent for fine particles , the average pore size is 0.3 to 5.0 μm and the maximum pore size is 10
μm or less, the density of pores is 1 × 10 ⁶ or more / cm ² ,
In addition, the holes are not independent in the thickness direction.
The present invention relates to a method for producing an image receiving paper , wherein a continuous polymer porous layer having a thickness of 2 to 100 μm is formed . Further, in such a method for manufacturing an image receiving paper,
By providing an adhesive layer and a separator in this order on the back side of the base material, the image receiving device having the above-described configuration for manufacturing an image receiving paper for labels is provided.
A method for producing paper can be provided .

The present invention also relates to a method for producing the above-mentioned image receiving paper .
Then, the polymer porous layer formed on the surface of the base material as described above is further subjected to heat and pressure treatment to produce an image receiving paper having excellent surface smoothness and having a surface gloss even after printing on a printer.
It is possible to provide a method for manufacturing the image receiving paper having the above configuration .

[0011]

Construction and operation of the present invention As the base material in the present invention, any of those known as image receiving papers can be used. Normally, plastic films such as polyester film and polypropylene synthetic paper are used in addition to paper such as high-quality paper, coat paper, art paper, and glassine paper. In the case of a plastic film, an anchor coating agent may be appropriately applied to improve the adhesion of the polymer porous layer. The thickness of the substrate can be arbitrarily selected according to the purpose of use.

In the present invention, when a polymer porous layer having a specific pore structure is formed on the surface of the substrate, a solvent solution of the polymer material, that is, the polymer material is dissolved in a single or mixed solvent for dissolution. And a coagulating solvent for coagulating the polymer material in the liquid after forming the solution into a thin film.

[0013] The solvent solution of the polymer material is not only a polymer material and a solvent for dissolving the polymer material, but also, for example, to increase the viscosity of the solution or to improve the hydrophilicity, May be added to impart an appropriate material. The concentration of the polymer material in the solution is selected so as to obtain a solution viscosity that is easy to apply and process, and a desired thickness, pore size, pore density, pore size distribution, and pore thickness direction of the polymer porous layer. Is appropriately selected depending on the continuity of the polymer, and is generally 3 to 50% by weight, preferably 5 to 30% by weight.

Examples of the polymer material include polyurethane, vinyl chloride-vinyl acetate copolymer, polyester, polymethyl methacrylate, and polyvinyl butyral.
, Polyvinyl formal, polyvinyl acetal, cellulose acetate, ethylene-vinyl acetate copolymer, polyethylene vinyl hydroxide, polyacrylate, polystyrene, nylon, styrene-isoprene copolymer, polypropylene, polychlorinated One or a mixture of two or more of vinyl, polyacetal, polyvinyl acetate, styrene-butadiene rubber, nitrile rubber, polybutadiene, polysulfone and the like are used. In particular, polyurethane, polyvinyl butyral, polyvinyl acetate
And cellulose acetate are preferably used.

The solvent for dissolving the polymer material is a solvent that is compatible with the solvent for coagulation and makes the polymer material insoluble. For example, dimethylformamide, hexane, heptane, cyclohexane, cycloheptane, benzene, toluene,
Hydrocarbons such as xylene are used, and among them, dimethylformamide is particularly preferred. The solvent is 1
It may be a seed or a mixed solvent of two or more.

With respect to such a solvent solution of a polymer material,
As a coagulating solvent for coagulating the material, for example, a polar solvent such as water, methanol, ethanol, propanol, ethylene glycol, and propylene glycol may be used to dissolve the solution. An appropriate one is selected according to the solvent used.

In the present invention, it is particularly preferable that the polymer material is polyvinyl acetal or polyvinyl butyral, the solvent for dissolution is dimethylformamide, and the solvent for coagulation is water. preferable.

In the present invention, the formation of the polymer porous layer using the above-mentioned substrate, the solvent solution of the polymer material and the coagulating solvent may be carried out as follows. First, a solvent solution of a polymer material is applied as a thin film on the surface of a base material. The coating thickness is usually 10 to 500 μm, preferably 20 to 100 μm
m, and the amount of the solvent in the coating film is usually 50 to 97% by weight, preferably 70 to 95% by weight.

Next, a solvent for coagulation is brought into contact with the coating film in the form of fine particles. This contact is performed by, for example, passing a coating film through a coagulation solvent vapor tank, or spraying a coagulation solvent onto the coating film surface. The fine particle state means that the particle size is 0.5
mm or less, preferably 0.1 mm or less, more preferably 0.01 mm or less. Contact time is usually 1
-10 minutes, the processing temperature is usually 0-80 ° C, preferably 0-80 ° C.
40 ° C. The amount of the coagulating solvent is usually 30 to 200% by weight, preferably 30 to 50% by weight, based on the coating amount per unit of the coating film.

When the contact is made in this manner, the fine particles of the coagulating solvent come into contact with and are absorbed by the coating film, and are diffused and mixed into the solvent in the coating film. The dissolved polymer material begins to solidify due to the mixing of the insoluble solvent, and the solidification progresses from the surface toward the inside. On the other hand, the solvent for coagulation that has lost its place due to coagulation of the polymer material accumulates in the gaps between the coagulating polymer materials and tends to become spherical due to the intermolecular cohesion.

This phenomenon starts from the surface layer of the coating film,
By gradually proceeding inside, a spherical solvent layer is generated one after another in the solidifying polymer material. When the expansion pressure exceeds the surface tension of the solvent layer, the spherical solvent layer is repelled from a part thereof and is connected to the adjacent spherical solvent layer inside the coating film. In this way, the spherical solvent layers are connected and reach from the contact side of the coagulating solvent to the opposite side, and a myriad of spherical micropores are connected and formed in a uniform state in the solidified polymer material coating film.

Coagulation by contact with such a coagulation solvent,
After the formation of the porous body, the target polymer porous layer is formed on the surface of the base material by drying the base material together, for example, by heating. When the base material is a paper such as a high-quality paper, a coated paper, an art paper, a glassine paper, etc., by drying while applying a tension at the time of drying, a wrinkle is not generated on the image receiving paper as a product. It is desirable to devise it.

In the image receiving paper of the present invention thus obtained, the polymer porous layer formed on the surface of the base material has an average pore diameter of 0.3 to 5.0 μm, preferably 0.5 to 3 μm, It has a specific pore structure having a pore diameter of 10 μm or less, preferably 5 μm or less, and a pore density of 1 × 10 ⁶ or more / cm ² , preferably 1 × 10 ⁷ to 1 × 10 ⁹ , and Having a relatively narrow pore size distribution with a pore size distribution usually in the range of 0.1 to 10 μm.

Another feature of this polymer porous layer is that its pores are connected in the thickness direction, that is, each pore is not independent in the thickness direction and each hole is continuous. It is mentioned that. The thickness of such a polymer porous layer is 2 to 100 μm, preferably 5 to 50 μm.

When an image receiving paper having such a characteristic configuration is used to print a pattern having a gradation by a variable dot size thermal head by a hot-melt type printer, particularly, a low gradation is obtained. An extremely good image with excellent dot reproducibility at the portion can be obtained. In addition, the sensitivity becomes extremely high probably because the pore structure of the polymer porous layer improves the heat storage property of the thermal head. These are due to the fact that the molten ink penetrates into pores that are continuous in the thickness direction by capillary action, and the fixability of small dots has been improved, and the size and density of the holes are within a certain range. This is presumed to be due to excellent reproducibility.

As described above, the image receiving paper of the present invention is excellent in small dot reproducibility, good in sensitivity and capable of printing at high density, and excellent in absorptivity to water-soluble ink. It is extremely useful as an image receiving paper. Further, the ink has good fixability of the printing ink and is useful as a raw material for printing plastic.

Further, the image receiving paper of the present invention can be used as a label image receiving paper by providing an adhesive layer and a separator in this order on the back side of the base material. Further, by subjecting the polymer porous layer formed on the surface of the base material to an appropriate heating and pressurizing treatment, for example, a calendering treatment, the above various types having excellent surface smoothness and having a surface gloss even after printing on a printer. Can be obtained.

[0028]

As described above, according to the present invention, it is possible to provide an image-receiving paper which is excellent in dot reproducibility, especially in reproducibility of high-definition dots, and is capable of improving recording density. In particular, a hot-melt type printer has a very good dot reproducibility and an image-receiving paper that can provide excellent print images with high recording density.
Further, a thermal sublimation type printer can be provided with an image receiving paper having excellent dyeing properties and a high recording density, and an ink jet printer can be provided with an image receiving paper having an excellent ink absorbency and quick drying properties. In addition, as a plastic sheet for printing, it is possible to provide a printing paper which is capable of performing high-quality printing with good fixability of printing ink and excellent dot reproducibility.

[0029]

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Polyvinyl acetal resin (Slek KS-5 manufactured by Sekisui Chemical Co., Ltd.) was added to dimethylformamide at a concentration of 7.
5% by weight, and this solvent solution was placed on a white PET (polyethylene terephthalate) film.
It was applied by an applicator so as to have a coating thickness of about 80 μm, and then introduced into a steam tank. The inside of the steam tank is maintained at a humidity of 80% or more and a temperature of 2 to 6 ° C. by a steam generator. The passing speed in the steam tank was about 10 minutes. Then, after washing with water at room temperature for about 10 minutes, drying was performed.

The image receiving paper thus manufactured is about 20
It has a polymer porous layer having a thickness of μm, and the average pore diameter of this layer is 2 μm.
μm, the maximum pore diameter is 5 μm, and the pore density is 2 × 10 ⁷ holes / cm ²
The pore size distribution was 0.5 to 5 μm. Further, the pores of the porous layer were not independent in the thickness direction, and each pore was continuous. FIG. 1 is an electron micrograph (2,000-fold magnification) of the surface of the polymer porous layer of the image receiving paper.
FIG. 2 is an electron micrograph (2,000 times magnification) of a cross section of the image receiving paper.

Comparative Example 1 A vinyl chloride-vinyl acetate copolymer was dissolved in dimethylformamide to a concentration of 25% by weight. Separately, an acrylonitrile-methyl acrylate copolymer was dissolved in dimethylformamide to a concentration of 25% by weight. A weight ratio of the former solvent solution and the latter solvent solution is 1
The mixture was mixed at a ratio of 0: 4 to prepare a coating solution. This coating solution is coated on a polyester film thinly coated with an unsaturated polyester resin, and the coating solution is added to water at 20 ° C. for 1 hour.
After immersion for 5 minutes, immerse in hot water of 90 ° C for 5 seconds,
A polymer porous layer having a thickness of about 25 μm was formed.

The image-receiving paper thus prepared has an average pore size of the polymer porous layer of 5 μm, a maximum pore size of 15 μm, a pore density of 1 × 10 ⁷ / cm ² and a pore size distribution of 0.5 to 15 μm.
μm, it was confirmed that the average pore diameter and the maximum pore diameter were large, the pore density was low, and the pore diameter distribution was considerably wide as compared with Example 1. FIG. 3 is an electron micrograph (magnification: 2, magnification) of the surface of the polymer porous layer of the image receiving paper.
FIG. 4 is an electron micrograph (2,000-fold magnification) of a cross section of the image receiving paper.

For the image receiving papers of Example 1 and Comparative Example 1, the sensitivity characteristics of three colors of Y (yellow), M (magenta) and C (cyan) were measured using a commercially available hot-melt color printer. It investigated using the densitometer RD-920.
5 is a Y color sensitivity characteristic, FIG. 6 is an M color sensitivity characteristic, FIG. 7 is a C color sensitivity characteristic, and each symbol a in FIGS.
Each symbol b is the result of Comparative Example 1.

Next, with respect to the image receiving papers of Example 1 and Comparative Example 1, a 20-step density gradation pattern was printed using a commercially available hot-melt color printer, and dot reproducibility was examined. Was. 8 and 9 show the results of Example 1, and FIGS. 10 and 11 show the results of Comparative Example 1. 8 and 10 are optical microscope photographs of the third stage from the low density side of the print gradation, and FIGS.
FIG. 11 is an optical microscope photograph at the tenth stage.

From the results shown in FIGS. 5 to 11, it can be seen that the image receiving paper of Example 1 has better dot reproducibility, higher sensitivity and higher recording density than the image receiving paper of Comparative Example 1. it is obvious. Actually, when a pattern with gradation was printed by a high-definition hot-melt color printer using both receiving papers, the ink-receiving paper of Example 1 had sufficient ink permeability at the four-color overlapping portion. Excellent dot reproducibility was obtained in low gradations and halftones, and a large sensitivity increase was obtained. On the other hand, with the image receiving paper of Comparative Example 1, an image with excellent gradation was apparently obtained, but dot reproducibility at low gradation was insufficient, dot missing occurred, and a small dot was observed. The fixing property of the dots was poor.

Example 2 A polyvinyl butyral resin (Slex BX-1 manufactured by Sekisui Chemical Co., Ltd.) was added to dimethylformamide at a concentration of 15%.
% By weight, and this solvent solution is mixed with white P
It was applied to an ET film by an applicator so as to have a coating thickness of about 35 μm, and then introduced into a steam tank. The humidity in the steam tank is 80% or more and the temperature is 23
It is kept at ° C. The passing speed in the steam tank was about 10 minutes. Then, after washing with water for about 10 minutes, drying was performed.

The image receiving paper thus manufactured is about 20
It has a polymer porous layer having a thickness of μm, and the average pore diameter of this layer is 2 μm.
μm, maximum pore diameter 5 μm, pore density 1 × 10 ⁷ / cm ²
The pore size distribution was 0.5 to 5 μm. Further, the pores of the porous layer were not independent in the thickness direction, and each pore was continuous. Next, using this image receiving paper, a high-resolution hot-melt color printer with a gradation pattern was printed. As a result, the ink penetration of the three-color superimposed portion was insufficient. Excellent dot reproducibility was obtained in tones and halftones.

Example 3 Polyvinyl butyral resin [ESLECT BX-5 manufactured by Sekisui Chemical Co., Ltd.] was added to dimethylformamide at a concentration of 7.
The solvent solution was dissolved to 5% by weight, and the solvent solution was applied on a white PET film by an applicator so as to have a coating thickness of about 70 μm, and then introduced into a steam tank. Humidity 80% or more, temperature 2
It is kept at 3 ° C. The passing speed in the steam tank was about 10 minutes. Then, after washing with water for about 10 minutes, drying was performed.

The image receiving paper thus manufactured is about 15
It has a polymer porous layer having a thickness of μm, and the average pore diameter of this layer is 2 μm.
μm, maximum pore diameter 5 μm, pore density 1 × 10 ⁷ / cm ²
The pore size distribution was 0.5 to 5 μm. Further, the pores of the porous layer were not independent in the thickness direction, and each pore was continuous. Next, using this image receiving paper, a high-resolution hot-melt color printer with a gradation pattern was printed. As a result, the ink penetration of the three-color superimposed portion was insufficient. Excellent dot reproducibility was obtained in tones and halftones.

Example 4 Cellulose acetate resin [Acetacet cotton L-4 manufactured by Daicel Corporation]
0] was dissolved in dimethylformamide so as to have a concentration of 15% by weight, and this solvent solution was applied on glassine paper having a basis weight of 90 g / m ² so as to have a coating thickness of about 35 μm.
After coating with a liquid, it was introduced into a steam tank. The inside of the steam tank is maintained at a humidity of 80% or more and a temperature of 23 ° C. by a steam generator. The passing speed in the steam tank was about 10 minutes. Then, after washing with water for about 10 minutes, drying was performed.

The image receiving paper thus manufactured is about 20
It has a polymer porous layer having a thickness of μm, and the average pore diameter of this layer is 1
μm, maximum pore diameter 3 μm, pore density 5 × 10 ⁷ / cm ²
The pore size distribution was 0.2 to 3 μm. Further, the pores of the porous layer were not independent in the thickness direction, and each pore was continuous. Next, using this image receiving paper, when printing a pattern with gradation, which is a high-definition hot-melt color printer, white spots are conspicuous on the whole. Although it is presumed to be due to the influence of the projection of the material), a very high-sensitivity image was obtained. The feature of this image receiving paper is that it is glossy as a whole. The ink permeability was sufficient, and excellent dot reproducibility was obtained at low gradation.

[Brief description of the drawings]

FIG. 1 is an electron micrograph (2,000-fold magnification) of the surface of a polymer porous layer in an image receiving paper of Example 1.

FIG. 2 is an electron micrograph (magnification: 2,0) of a cross section of the image receiving paper.
00 times).

FIG. 3 is an electron micrograph (2,000-fold magnification) of the surface of a polymer porous layer in the image receiving paper of Comparative Example 1.

FIG. 4 is an electron micrograph (magnification: 2,0) of a cross section of the image receiving paper.
00 times).

FIG. 5 is a characteristic diagram showing Y color sensitivity characteristics of the image receiving papers of Example 1 and Comparative Example 1.

FIG. 6 is a characteristic diagram showing M color sensitivity characteristics of the image receiving paper.

FIG. 7 is a characteristic diagram showing C color sensitivity characteristics of the image receiving paper.

FIG. 8 is an optical micrograph (magnification: 150) of the third stage from the low density side where the print gradation indicating dot reproducibility of the image receiving paper of Example 1 is low.
Times).

FIG. 9 is an optical microscope photograph (magnification: 150 times) of the tenth stage.
It is.

FIG. 10 is an optical microscope photograph (magnification: 15) of the third stage from the low density side where the print gradation indicating dot reproducibility of the image receiving paper of Comparative Example 1 is low.
0 times).

FIG. 11 is an optical micrograph (magnification 150) of the tenth stage.
Times).

[Explanation of symbols]

 a Sensitivity characteristic curve of Example 1 b Sensitivity characteristic curve of Comparative example 1

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Sugawara 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nippon Denko Corporation (72) Inventor Hiroshi Shibata 1-2-1, Shimohozumi, Ibaraki-shi, Osaka (Japanese) JP-A-2-162041 (JP, A) JP-A-59-45335 (JP, A) JP-A-57-90028 (JP, A) JP-A-4- 292644 (JP, A) JP-A-6-80817 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00 B41M 5/38-5/40 C08J 9/28 101 B29C 67/06

Claims (3)

(57) [Claims] 1. A solvent solution of a polymer material is applied to the surface of a substrate.
It is applied in a thin film and is compatible with the solvent of the above solution.
Coagulation solvent that does not dissolve polymer material
The average pore size is 0.3 to 5.0 μm, the maximum pore size is 10 μm or less, the density of the pores is 1 × 10 ⁶ or more / cm ² , and the thickness of the pores is direction
Not independent of each other, each hole is continuous, thickness
There preparation of the image receiving sheet, which comprises forming a porous polymer layer is 2 to 100 m. 2. An adhesive layer and a separator on the back side of a substrate.
Are provided in this order to manufacture a label receiving paper.
3. The method for producing an image receiving paper according to item 1 . To 3. A porous polymer layer formed on the surface of the base material, is subjected to further heating and pressing treatment, excellent surface smoothness, according to claim 1 for producing an image-receiving paper having a surface gloss even after the printer printing Or the method for producing an image receiving paper according to 2 .