JP2001198998A - Sheet for printing, printing sheet, and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing sheet capable of issuing a printing sheet by expediently giving ink information via various type printers and having excellent durability and stain resistance such as scuff resistance, water resistance, solvent resistance and heat resistance, a method for manufacturing the sheet and a sheet for printing capable of manufacturing the printing sheet. SOLUTION: The sheet for printing comprises a porous layer capable of being made non-porous at least on a front surface in such a manner that a gel content of the layer is 20 to 90%. The printing sheet comprises ink information in the porous layer of the sheet for printing in such a manner that the at least front surface of layer is non-pored. The method for manufacturing the printing sheet comprises the steps of giving and impregnating an ink to the layer of the sheet for printing and then making the front surface of the layer non-porous.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing sheet capable of providing ink information having excellent durability such as abrasion resistance and heat resistance, a printing sheet and a method for manufacturing the printing sheet.

[0002]

2. Description of the Related Art Heretofore, there has been known a printing sheet for a printer, a copying machine, or the like in which ink is penetrated into a porous layer of a porous substrate such as paper or cloth. Such a printed sheet has the advantage that the ink penetrates into the porous layer and is protected by the porous layer, and the applied ink information is less likely to be lost due to friction, scratching, scratching and the like.

However, there has been a problem that the porous layer itself is vulnerable to abrasion or scratching and is easily broken, and the ink information is lost along with the damage. Further, there is a problem that even when an ink-soluble solvent enters the porous layer, ink information is lost or bleeds. Therefore, the durability of the ink information is limited by the strength, water resistance, and solvent resistance of the porous layer (the property of preventing the contact between the ink-soluble solvent and the ink in the porous layer). .

[0004]

SUMMARY OF THE INVENTION According to the present invention, a printing sheet can be issued by providing ink information via various printers on an occasional basis, and the ink information has abrasion resistance, water resistance, solvent resistance, heat resistance, etc. It is an object of the present invention to provide a printing sheet having excellent durability and stain resistance, a method for manufacturing the same, and a printing sheet capable of manufacturing the printing sheet.

[0005]

That is, the gist of the present invention is as follows.
[1] A printing sheet having at least a porous layer capable of rendering at least a surface nonporous, wherein the gel fraction of the porous layer is 20 to 90%; [2] [3] The printing sheet according to [1], wherein the printing layer has ink information in the porous layer, and at least the surface of the porous layer is subjected to a nonporous treatment. The present invention relates to a method for producing a printing sheet, characterized in that at least the surface of the porous layer is subjected to a non-porous treatment after the ink is applied to and penetrated into the porous layer in the printing sheet according to the above [1].

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The printing sheet according to the present invention has at least a porous layer on at least the surface thereof so that the surface can be made nonporous. The printing sheet may be in an appropriate form having the porous layer as an ink receiving layer. Examples thereof include a single-layer sheet formed of a porous layer itself, and a porous layer 1 and a reinforcing substrate 2 as illustrated in FIG.
, A porous layer in which a porous layer and a reinforcing base material are bonded via an adhesive layer, and a mode in which an adhesive layer is provided on the back surface on the non-printing side. In particular, the printing sheet shown in FIG. 1 has a reinforcing substrate 2 provided below the porous layer 1 and an adhesive layer 3 provided thereunder.
And is adhered to the adherend 5.

The porous layer is made of a material which can be made nonporous at least on the surface by an appropriate method such as a melting treatment by heating or a dissolving treatment by a solvent, and has a gel fraction of 20%.
When the content is about 90%, remarkable destruction of the porous layer itself due to excessive melting treatment, dissolution treatment, or the like can be prevented. The gel fraction of the porous layer is 20 to 90%, preferably 25 to 85%. The lower limit of the gel fraction is 20% or more from the viewpoint of obtaining a porous layer having sufficient heat resistance,
In addition, the upper limit is 90 from the viewpoint of sufficient nonporosity.
% Or less. The gel fraction refers to a value measured by the method described in Examples described later.

As the material for forming the porous layer, any suitable material may be used according to the purpose of use of the printing sheet and the like, and there is no particular limitation. For example, a combination of a thermoplastic resin and a curable resin is used.

Examples of the thermoplastic resin include olefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer and ethylene-vinyl acetate copolymer, and vinyl resins such as polystyrene, polyvinyl chloride, polyvinyl acetal, and polyvinyl acetate. And polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, and thermoplastic elastomers.

As the curable resin, acrylic resins such as polymethyl methacrylate and polyacrylate;
Rubber-based resins such as polynorbornene and polybutadiene, polyamide imide, polyether imide, and polyimide are exemplified.

These thermoplastic resins and curable resins may be used alone or in combination of two or more. Among the combinations of the thermoplastic resin and the curable resin, an olefin resin and a rubber resin are preferable because they have good compatibility and can form a flexible and tough porous layer. Further, the olefin-based resin and the rubber-based resin are low in cost for making them nonporous by heating, and are excellent in chemical resistance. The mixing ratio of these resins is not particularly limited. For example, the ratio of thermoplastic resin / curable resin (weight ratio) is preferably 99/1 to 50/50, and 97/3 to 60/40. Is more preferred. Further, in forming the porous layer, a component such as an additive for improving the adsorptivity may be appropriately added as necessary.

In the present invention, a microporous film can be used as the porous layer. For the production of the microporous film, known methods such as a dry film forming method and a wet film forming method can be used. For example, the thermoplastic resin, a resin composition comprising a curable resin and the like are mixed with a solvent, kneaded, formed into a sheet while being heated and dissolved, then rolled, stretched in one or more axial directions, and the solvent is extracted and removed. It can be manufactured by the following.

Examples of the solvent include aliphatic or cyclic hydrocarbons such as nonane, decane, undecane, dodecane, decalin, and liquid paraffin, and mineral oil fractions having a boiling point corresponding to these, such as liquid paraffin. Non-volatile solvents containing a large amount of alicyclic hydrocarbons are preferred. The amount of the solvent used is preferably 60 to 95% by weight of the mixture of the resin composition and the solvent. The step of kneading the mixture of the resin composition and the solvent and forming the mixture into a sheet shape can be performed by a known method, and kneading is performed in a batch manner using a Banbury mixer, a kneader, or the like, and then, the cooled metal It may be sandwiched between plates or rolls and rapidly cooled to form a sheet-like molded product by rapid crystallization, or a sheet-like molded product may be obtained using an extruder equipped with a T-die or the like. The kneading may be performed under appropriate temperature conditions, and is not particularly limited.
0 ° C.

The thickness of the sheet-like molded product thus obtained is not particularly limited, but is preferably 3 to 20 mm, and 0.5 to 2 mm by a rolling process such as a heat press.
mm. The temperature of the rolling process is 1
00-140 ° C is preferred.

The method of stretching the sheet-like molded product is not particularly limited, and may be a usual dent method, roll method, inflation method or a combination of these methods. And any method such as biaxial stretching can be applied. In the case of biaxial stretching, either vertical or horizontal simultaneous stretching or sequential stretching may be used. The temperature of the stretching treatment is preferably 100 to 140 ° C.

The desolvation treatment is a step of forming a microporous structure by removing a solvent from a sheet-like molded product.
It can be carried out by washing the sheet-like molded product with a solvent to remove the residual solvent. Examples of the solvent include hydrocarbons such as pentane, hexane, heptane, and decane; chlorine hydrocarbons such as methylene chloride and carbon tetrachloride; fluorinated hydrocarbons such as ethane trifluoride; and ethers such as diethyl ether and dioxane. Volatile solvents,
These can be used alone or in combination of two or more. The washing method using such a solvent is not particularly limited, and examples thereof include a method of immersing a sheet-like molded product in a solvent to extract the solvent, a method of showering the solvent on the sheet-like molded product, and the like.

In order to obtain a porous layer having a desired gel fraction after the resin composition is formed into a film by the known method to obtain a microporous film, it is preferable to form the microporous film. The resin composition to be crosslinked. For the crosslinking, one or more selected from the group consisting of heat, ultraviolet rays and electron beams can be used. Among these, a cross-linking treatment using heat is desirable in view of the structural stability of the microporous film. By performing these crosslinking treatments, the heat resistance (film breakage resistance at high temperatures) of the microporous film is greatly improved. Usually, since the stretch molded body is heat-set by heat treatment in a post-process, it is possible to carry out the heat treatment simultaneously with the above-mentioned cross-linking treatment. .

In the case where heat is used as the method for the crosslinking treatment, a one-step heat treatment method in which heat treatment is performed once, a multi-step heat treatment method in which heat treatment is first performed at a low temperature, and then heat treatment is further performed at a high temperature, or A temperature-raising heat treatment method in which a heat treatment is performed while raising the temperature may be used, but it is desirable to carry out the treatment without impairing the original characteristics of the microporous film such as the air permeability. In the case of a single-stage heat treatment, the temperature is preferably from 40 ° C to 140 ° C, although it depends on the composition of the microporous film. In addition, starting the heat treatment from a low temperature and then increasing the treatment temperature, the heat resistance gradually improves with the curing of the microporous film, so that the heating does not impair the original properties such as air permeability. Exposure to high temperatures becomes possible. Therefore, in order to complete the heat treatment in a short time without deteriorating various characteristics, a multi-stage or elevated temperature heat treatment is preferable.

The initial heat treatment temperature of the multi-stage heat treatment depends on the composition of the microporous film, but is preferably 4
Although it depends on the composition of the microporous film, the temperature of the second heat treatment is preferably from 90 to 140C, preferably from 0 to 90C. If necessary, heat treatment at a higher temperature and for a shorter time in the third and subsequent stages may be performed. The treatment time depends on the composition of the microporous film, but is 1 to 4 for the first heat treatment.
About 8 hours, 0.5-
About 6 hours are preferable. In the case of the elevated temperature heat treatment, the heat treatment may be performed under the same conditions as those of the above-described multi-stage heat treatment.

When ultraviolet rays are used, for example, the microporous film after film formation is impregnated with a methanol solution containing a polymerization initiator, and after drying the solvent, the microporous film is irradiated with a mercury lamp to perform a crosslinking treatment. Can be applied.

In the case of using an electron beam, for example, the microporous film after film formation is irradiated with a radiation dose of 0.1 to 10 Mrad. The atmosphere at the time of irradiation may be air as in the case of the heat treatment method, or may be an atmosphere of an inert gas such as nitrogen gas or argon gas in order to control the state of crosslinking.

The degree of cross-linking changes by adjusting the temperature, time and the like by these cross-linking treatments, and the gel fraction can be adjusted.

Following the crosslinking step, the microporous film may be generally heat-set (heat-set) to prevent heat shrinkage. In particular, in the present invention, by performing the cross-linking treatment using heat as described above, depending on the processing conditions, substantially heat setting is also possible, but when the heat setting is insufficient, the heat shrinkage is reduced. For better prevention, heat setting may be performed by further heating after the crosslinking treatment. The heat setting may be performed, for example, at 110 to 140 ° C. for about 0.5 to 2 hours.

The microporous film obtained as described above is suitably used as a porous layer. The porous layer, from the viewpoint of ink permeability and the ability to form clear ink information,
It is preferable to have a communicating hole at least in the layer thickness direction. The average pore diameter of the pores is preferably 0.01 to 20 μm, and 0.02 to
18 μm is more preferred. Further, the maximum pore diameter is preferably 50 μm or less, from the viewpoint of the speed of the nonporous treatment, and 0.1 μm.
01 to 40 μm is more preferable. In addition, from the viewpoints of ink permeability, layer strength, and the like, the porosity of the porous layer is preferably 30 to 90%, and more preferably 30 to 85%. The average pore diameter, the maximum pore diameter, and the porosity are measured by the methods described in Examples described later. The porous layer may be subjected to a surface treatment such as a plasma treatment or a corona treatment in order to improve the permeability of the ink into the holes.

The printing sheet of the present invention is, for example, as shown in FIG.
May be laminated. In that case, for example, by a method of providing a porous layer on both sides of the reinforcing substrate,
A double-sided printing sheet can be used as in the case of a single-layer sheet of a porous layer.

As the reinforcing base material, for example, an appropriate material or form such as paper, nonwoven fabric, cloth, metal foil, resin film (PET or the like), or a composite thereof, depending on the intended use of the printing sheet. Can be used. Specific examples of the paper and the resin film include those described in JP-A-11-170690, page 4, left column, lines 24 to 33.

The thickness of the porous layer or the reinforcing substrate can be appropriately determined according to the purpose of use of the printing sheet.
Generally, the thickness is preferably 3 to 500 μm, more preferably 5 to 300 μm, from the viewpoint of the amount of ink permeation and thinning.

The printing sheet of the present invention includes, for example, FIG.
As shown in FIG. 7, an adhesive layer 3 can be provided on the back side of the non-printing side as needed. For the formation of the adhesive layer, for example, a rubber, acrylic, silicone, vinylalkyl ether, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, cellulose, urethane, polyester, polyamide, etc. One kind or two or more kinds of adhesives can be used. In addition,
The adhesive layer is intended to attach the printing sheet to the adherend 5 and can be provided in advance on the printing sheet before applying the ink information, or can be provided after the printing sheet is formed. . In addition, a known method can be used for attaching the adhesive layer 3, and there is no particular limitation. For example,
The method described in JP-A-9-39141, page 5, left column, lines 41 to 48 can be used. The thickness of the adhesive layer can be determined according to the purpose of use, and for example, is preferably 1 to 500 μm.

In the printing sheet of the present invention having the above-described structure, since the porous layer provided on the surface shows the internal permeability (absorbency) of the ink, various printing papers, label papers, etc. It can be used as paper for various printing methods such as printing paper, among others, in particular, a method of printing with liquid ink during printing. The ink that can be used in the present invention may be any known ink, and examples thereof include those described in JP-A-9-39141, page 4, right column, lines 11 to 40.

The printing sheet of the present invention can be manufactured by giving ink information to the porous layer of the printing sheet and then subjecting at least the surface of the porous layer to a nonporous treatment. As the method of providing, for example,
An appropriate method such as a handwriting method, a printing method, and an ink application method via a mask can be employed. Also, as a printing method,
In addition to the screen printing method and the gravure printing method, printing methods using various printers such as a hot-melt type, a thermal sublimation type, a thermal transfer type, and an inkjet type can be adopted. Printing method by on-demand printing is preferable from the viewpoints of printing accuracy, internal penetrability of ink, and formability of a printed sheet. The printing device is not particularly limited. When the above-described thermal transfer method or electrophotographic method is used, the ink is heated and melted at the time of fixing to liquefy the ink, and ink information in which the ink permeates the inside of the porous layer is formed. The conditions for applying these inks are not particularly limited as long as they are known.

Examples of the ink information to be applied include arbitrary information including characters, symbols, figures, etc., such as print patterns, bar code patterns, and graphic patterns.

In the printing sheet according to the present invention, as shown in FIG. 2, after the ink information 4 is formed on the porous layer 1 of the printing sheet, at least the surface of the porous layer is made nonporous. A nonporous layer (not shown) is formed. By performing such a nonporous treatment, a printed sheet having excellent chemical resistance such as abrasion resistance, scratch resistance, water resistance, and solvent resistance and durability can be produced. The surface of the porous layer on which the nonporous treatment is performed refers to the surface or both surfaces of the single layer sheet to which the ink information is provided in the case of a single layer sheet composed of the porous layer itself. In addition, as illustrated in FIG. 1, a multilayer structure of the porous layer 1 and the reinforcing base material 2,
In the case of a multi-layer configuration in which a porous layer and a reinforcing base material are bonded via an adhesive layer, and a configuration in which an adhesive layer is provided on the back side of the non-printing side, it refers to the surface of the porous layer on the side to which ink information is added.

The nonporous treatment performed after the ink has been permeated into the porous layer by an appropriate method includes, for example, a heating method,
Appropriate methods such as a heating and pressurizing method and a contacting method with a solvent soluble in a porous layer can be mentioned. Among them, from the viewpoint of preservation of the ink information previously applied, a melting method by heating, particularly heating and pressurizing. Is preferred. Specific examples of the heating / pressing method include a heating press method, a thermal head pressing method, and a heating roll method. Such a heating method and a heating and pressing method are preferably applied to a porous layer made of a thermoplastic resin.However, even in a porous layer mainly containing a crosslinkable component, the molten component is pressed to make it nonporous, In addition, a printing sheet having excellent durability can be obtained because of containing a crosslinking component.

When a heating method is used as the condition of the nonporous treatment, the treatment temperature is 100 to 250 ° C., and the treatment time is 10 minutes.
About 1000 seconds is preferable. When using the heating and pressing method,
The processing temperature is preferably 100 to 200 ° C., the processing pressure is 20 to 500 kPa, and the processing time is preferably 1 to 600 seconds. When using a contact method with a porous layer-soluble solvent, the solvent is an aliphatic or cyclic hydrocarbon, toluene, xylene or a mixed solvent containing these,
The processing temperature is preferably 100 to 200 ° C., and the processing time is preferably 1 to 600 seconds.

The printing sheet obtained in this manner can be printed with various types of printers by giving ink information to the occasion, and the abrasion resistance, water resistance,
It is excellent in durability such as solvent resistance and heat resistance and in stain resistance.

[0036]

EXAMPLES The methods for measuring the average pore diameter, the maximum pore diameter, the porosity and the gel fraction of the microporous film used as the porous layer in Examples and Comparative Examples are described below.

(Average pore size and maximum pore size) The pore size distribution was measured by the BJH method using a pore distribution measuring device “ASAP2010” of the specific surface area by the nitrogen desorption method of Shimadzu Corporation. Determine the average pore size and the maximum pore size.

(Porosity) The prepared microporous film has a diameter of
Cut out to 3.9 cm, determine its volume and weight, and
The result was calculated using the following equation. Porosity (%) = 100 x [volume (cm^Three)-Weight (g) / Resin group
Average density of the product (g / cm ^Three)] / Volume (cm^Three)

(Gel fraction)
The sample was cut into a square of m × 4 cm, and sandwiched with a metal mesh of 5 cm × 10 cm to obtain a sample of 5 cm × 5 cm square. The initial weight of this sample was measured and 100 ml of m-xylene (boiling point 13
9 [deg.] C.), the temperature was raised, and the xylene was boiled for 3 hours, taken out and dried, and the gel fraction R (%) was measured from the weight change. R (%) = 100 × P ₁ / P ₀ (P ₀ : initial weight, P ₁ :
Weight after boiling xylene treatment)

Example 1 Powder of a ring-opening polymer of norbornene (Nippon Zeon Co., Ltd.)
"NOSOLEX NB", weight-average molecular weight 2 million or more) polyethylene 88 with 12% by weight and weight-average molecular weight 3 million
15 parts by weight of a resin composition consisting of
Parts by weight were uniformly mixed into a slurry, and the mixture was melted and kneaded at a temperature of 160 ° C. for about 60 minutes using a small kneader. Thereafter, these kneaded materials were sandwiched between metal plates cooled to 0 ° C. and rapidly cooled in a sheet shape. These quenched sheet-like moldings were
The sheet was heat-pressed at a temperature of 115 ° C. until the sheet thickness became 0.4 to 0.6 mm, and was simultaneously biaxially stretched 3.5 × 3.5 times at a temperature of 115 ° C. and desolvation treatment was performed using heptane. Thereafter, the obtained microporous film was heat-treated in air at 85 ° C. for 2 hours, and then heat-treated at 130 ° C. for 2 hours to obtain an average pore size of 0.2.
03μm, maximum pore size 0.1μm, porosity 50%, gel fraction 80
%, A 25 μm thick microporous film was obtained. This microporous film was laminated on a 75 μm thick white PET film to obtain a printing sheet, and the porous layer (microporous film portion) was applied to an inkjet printer (“PM-770C” manufactured by Seiko Epson). After performing color printing with water-based ink, it was passed through a pressing device at 98 kPa, 180 ° C,
The surface of the porous layer was made nonporous by heating and pressurizing treatment (heating press method) under the condition of 15 seconds to obtain a printed sheet.

Example 2 A printed sheet was obtained in the same manner as in Example 1 except that a figure was handwritten with an oil-based ink magic ("Mackey", manufactured by Zebra Corporation) instead of printing with an ink jet printer.

Example 3 Norbornene Ring-Opening Polymer Powder (Nippon Zeon Co., Ltd.)
Nosorex NB, weight average molecular weight 2 million or more) 10% by weight, thermoplastic elastomer (Sumitomo Chemical Co., Ltd., "TPE821") 21% by weight, weight average molecular weight 300
15 parts by weight of a resin composition comprising 69% by weight of polyethylene and 85 parts by weight of liquid paraffin were uniformly mixed in a slurry state, and the mixture was dissolved and kneaded at a temperature of 160 ° C. for about 60 minutes using a small kneader. Thereafter, these kneaded materials were sandwiched between metal plates cooled to 0 ° C. and rapidly cooled in a sheet shape. These quenched sheet-like moldings are prepared at a temperature of 115 ° C and a sheet thickness of 0.4 to 0.6 mm.
And press at 115 ° C simultaneously
The film was biaxially stretched to 3.5 × 3.5 times, and subjected to a desolvation treatment using heptane. Thereafter, the obtained microporous film was heat-treated in air at 85 ° C. for 2 hours and then at 122 ° C. for 2 hours to obtain an average pore size of 0.04 μm, a maximum pore size of 0.15 μm, and a porosity.
A microporous film having 46%, a gel fraction of 60% and a thickness of 30 μm was obtained. This microporous film was laminated on a 75 μm-thick white PET film to obtain a printing sheet, and the porous layer (microporous film portion) was applied to an inkjet printer (manufactured by Seiko Epson, “PM-770C”). After performing color printing with water-based ink,
The surface of the porous layer was made nonporous by heating and pressurizing (heating press method) under the conditions of 98 kPa, 180 ° C. and 15 seconds to obtain a printed sheet.

Example 4 A printed sheet was obtained in the same manner as in Example 2 except that a graphic was handwritten using an oil-based ink magic ("Mackey", manufactured by Zebra Corp.) instead of printing with an ink jet printer.

Comparative Example 1 A printed sheet was obtained in the same manner as in Example 1 except that the porous layer surface was not subjected to a nonporous treatment by heating and pressing.

Comparative Example 2 A printed sheet was obtained in the same manner as in Example 2 except that the surface of the porous layer was not subjected to a nonporous treatment by heating and pressing.

Comparative Example 3 A printing sheet was obtained in the same manner as in Example 1 except that a white PET film having a thickness of 100 μm was used as a printing sheet, and no heat and pressure treatment was performed.

Comparative Example 4 A white PET film having a thickness of 100 μm was used as a printing sheet, and a printing sheet was obtained in the same manner as in Example 2 except that the heating and pressing treatment was not performed.

Comparative Example 5 A microporous film having a thickness of 26 μm, an average pore diameter of 0.03 μm, a maximum pore diameter of 0.1 μm, a porosity of 65%, and a gel fraction of 0% (“Celgard K-817” manufactured by Celanese Corp.) was used. Otherwise, a printed sheet was obtained in the same manner as in Example 1.

Evaluation Test The printed sheets obtained in the examples and comparative examples were visually evaluated for the following characteristics, and the results are shown in Table 1.

(Printability) It was determined whether or not normal printing was possible based on the printing state, and evaluation was made as ○ when the ink was fixed normally, and as X when the ink was not fixed.

(Scratch resistance) The surface of the print sheet was rubbed 20 times with a sand eraser rubber at a load of about 196 kPa, and the scratch resistance was determined based on the remaining state of the applied ink information. The evaluation was evaluated as Δ when there was a change but the ink information could be read, and × when the ink information changed to a state where the ink information could not be read.

(Water resistance) When the surface of the printing sheet is rubbed 50 times with a load of about 196 kPa with a water impregnated rag, the water resistance is determined based on the remaining state of the applied ink information, and there is no change in the ink information. Was evaluated as ○, when there was a change but the ink information could be read, and as Δ, and when the ink information changed to a state where it could not be read, as ×.

(Solvent resistance) The surface of the printing sheet was rubbed 50 times with a load of about 196 kPa using a waste cloth impregnated with toluene.
Determine the solvent resistance from the remaining state of the applied ink information,
The case where there was no change in the ink information was evaluated as ○, the case where there was a change but the ink information could be read was evaluated as Δ, and the case where the ink information changed to a state where it could not be read was evaluated as ×.

(Heat Resistance) The surface of the printed sheet was heated and pressurized at 98 kPa, 200 ° C. and 15 seconds through a press device, and the heat resistance was determined from the remaining state of the applied ink information. Was evaluated as ○ when no change was observed, Δ when there was a change but the ink information was readable, and X when the ink information was changed to an unreadable state.

(Stain resistance) A coffee liquid was dropped on the surface of the printing sheet, and after 1 minute, wiped off with a waste cloth. The stain state was determined, and the stain resistance was judged. △, X: If most of the coffee liquid remains
Was evaluated.

[0056]

[Table 1]

From the results shown in Table 1, it can be seen that by making at least the surface of the porous layer made of a microporous film nonporous, the durability of ink information is dramatically improved.

[0058]

According to the present invention, it is possible to issue a print sheet by providing ink information occasionally via various printers, and the ink information penetrates into the porous layer and the surface becomes nonporous. A highly durable printed sheet that is protected and has excellent scratch resistance, water resistance, and solvent resistance, and has a high heat resistance because of having a structure containing a crosslinking component, can be formed. In addition, it is possible to easily wipe off the attached contamination, to have excellent contamination resistance, and to prevent obstruction of reading of ink information. Another advantage is that no separate cover treatment is required by making the porous layer nonporous.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a printing sheet of the present invention.

FIG. 2 is a schematic explanatory view of a printed sheet of the present invention.

[Explanation of symbols]

 1 Porous layer 2 Reinforcement substrate 3 Adhesive layer 4 Ink information 5 Adherend

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA13 FC06 2H086 BA05 BA15 BA41 2H111 AA10 AA11 AA26 AA51 CA03 CA11 CA30 4F100 AK04 AK42 AK80 AL05 AT00B BA02 BA43 DJ10A EH463 EH613 EJ013 EJ423 J90JBJJBJJBJJBJJBJJBJJBGBJ

Claims (8)

[Claims] 1. A printing sheet having at least a porous layer at least on the surface of which the surface can be made nonporous, wherein the gel fraction of the porous layer is 20 to 90%. 2. The porous layer according to claim 1, wherein the porous layer has pores having an average pore diameter of 0.01 to 20 μm and a maximum pore diameter of 50 μm or less and communicating at least in the layer thickness direction, and the porosity of the porous layer is 30 to 90%. Printed sheet as described. 3. A printing sheet according to claim 1, wherein the printing sheet has ink information in the porous layer, and at least the surface of the porous layer has been made nonporous. . 4. The printing sheet according to claim 1, wherein after the ink is applied to the porous layer of the printing sheet according to claim 1 or 2, the porous layer is subjected to a nonporous treatment at least on the surface of the porous layer. Production method. 5. The method according to claim 4, wherein the ink is a liquid ink. 6. The method according to claim 4, wherein the application of the ink is performed by an ink jet system, a thermal transfer system, or an electrophotographic system.
The manufacturing method as described. 7. The production method according to claim 4, wherein the nonporous treatment is carried out by a heating method, a heating and pressurizing method or a contacting method with a solvent soluble in a porous layer. 8. The heating / pressing method is a heating press method, a thermal head pressing method, or a heating roll method.
The manufacturing method as described.