JPH103176A - Printing paper and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to print characters and graphics on the surface of a plastic film with a printing machine or copying machine of an electrostatic copying type. SOLUTION: The surface of the plastic film 2 consisting essentially of polyethylene terephthalate is printed and coated with a coating material 1 which is prepd. by mixing and dispersing a pigment and a thermosetting resin having a curing temp. of 220 to 320 deg.C with and in an org. solvent, and is used as ink. The film is then dried at a temp. lower than the curing temp. of the thermosetting resin. As a result, the nature of the plastic film 2 is effectively utilized as it is and carbon particles are included therein by the coating material and, therefore, the film does not change even if the film is wet with water. The printed characters and graphics are hardly erasable even if the film is rubbed. The paper which withstands long-term preservation is thus inexpensively obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to paper which can be printed by a laser printer or an electrostatic copying machine. The present invention relates to a printing paper based on a plastic film.

[0002]

[Prior Art] With the rapid development of office equipment,
Machines or laser printers have become widespread. In these apparatuses, print information is electrostatically formed on the paper surface as a graphic pattern, and a powdery paint mainly composed of carbon particles (or color paint particles) is sprayed on the paper surface, and the printed information is formed according to the graphic pattern. An optically recognizable paint pattern is drawn on the surface, and the paint pattern is pressed onto a heating drum to fix the paint pattern on the paper surface.

Further, personal computers and word processors have been developed, and laser printers have been highly developed as printing devices connected thereto.

Conventionally, using paper made from pulp,
The technology for performing copying or printing as described above has been highly developed, the printing cost has been significantly reduced, and high-speed printing has become possible.

[0005] As a printing paper for an overhead projector (OHP), a paper using a transparent mylar film is known. It is only used for applications that require transparent paper.

[0006]

On the other hand, since paper consumes wood resources, inexpensive paper other than paper is required. In addition, even if the price is not so low, there is a demand for a printing paper which does not break even when wet with water, or whose printing on the surface does not disappear due to friction due to long-term storage. For example, a label attached to a product, a poster displayed at a storefront, a product warranty or a description, and the like.

[0007] In a laser printer or a copying machine, the temperature of the heating drum is approximately 250 to 300 ° C. On the other hand, some plastic films and other chemical films have properties superior to paper, such as durability against long-term storage and durability against repeated use. However, these chemical films generally include those that become liquid, soften, and harden depending on their properties when heated. Therefore, if these chemical films are used as paper for a printing apparatus having a heating drum as described above, satisfactory printing cannot be performed, and the printing machine may be damaged.

Further, many plastic films are transparent, and it is good to use the transparent properties such as those used for OHP as described above. However, in order to obtain paper instead of ordinary paper, transparent paper is used. It is often inconvenient if left alone.

The inventor of the present application has attempted to obtain a paper which can be used in an electrostatic copying type printer or copier while maintaining the excellent properties of these plastic films. The inventor of the present application has made numerous attempts to complete the present invention.

That is, according to the present invention, it is possible to perform printing on the surface of a plastic film with an electrostatic copying type printing machine or a copying machine, and without losing the properties of the plastic film. It is an object of the present invention to provide a new sheet of paper in which the printed characters and figures are not easily erased, are resistant to long-term storage, and can be obtained at low cost.

[0011]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
An ink is prepared by mixing and dispersing a pigment and a thermosetting resin having a curing temperature of 220 to 320 ° C. in an organic solvent as an ink. The ink is applied to the surface of a plastic film mainly composed of polyethylene terephthalate by printing, and the curing temperature of the thermosetting resin is determined. It is characterized by drying at a lower temperature.

In order to manufacture printing paper by this method, it is necessary to use a plastic film which does not deform at the temperature of the heating drum (about 250 to 300 ° C.). It has been found that a biaxially stretched film using polyethylene terephthalate as a main raw material is suitable for this. It is available as a catalog product on the market under the name Polyester Film. A close examination of such polyester films shows that their melting points exceed 280 ° C., some of which are around 260 ° C. It was also found that even if such a material having a low melting point was actually passed through a heating drum at a printing speed, it was not immediately melted and deformed. In other words, it can be seen that even when the temperature of the heating drum is 300 ° C., when the film is processed at the printing speed, the entire film does not reach the temperature of the heating drum, but is in a somewhat lower temperature range.

Next, the inventor of the present application attempted to print a pigment on the surface of such a plastic film by a conventionally known printing technique. The pigment is printed on the surface of the plastic film using a well-known printing device equipped with a plate cylinder. And, in the process of conducting various tests, the pigment is dispersed in the thermosetting resin,
This is mixed and prepared in an organic solvent,
It was found that printing on the surface of the film was good.
In other words, the thermosetting resin was given a paper property so as not to flow out, and was in a state before the thermosetting resin was thermoset, and was in contact with the heating drum of the printing apparatus. Sometimes it has been found that it is good to have the surface thermoset.

More specifically, when a pigment is dispersed in a thermosetting resin by using an organic solvent, and this is printed and applied on the surface of a plastic film by a printing technique and dried at a low temperature, the pigment becomes a plastic. It is kept attached to the surface of the film. It can be packaged and marketed. No phenomena such as fingerprints can be seen even when touched with a finger.

When electrostatic copying is performed using the plastic film in this state as paper, carbon particles adhere according to the electrostatic pattern. Then, it was found that when it came into contact with the heating drum, the thermosetting resin was cured so as to embed the carbon particles therein. This was confirmed by observing the surface with a microscope. In the state where the thermosetting resin is cured, since the carbon particles are embraced inside thereof, by rubbing or by moisture,
It was found that the carbon particles did not detach from the surface, and printing with extremely high stability was possible.

The present inventor repeated various tests on the components of the thermosetting resin and the organic solvent. As for the thermosetting resin, as described above, the thermosetting resin is cured by holding the carbon particles therein from about 220 ° C. slightly lower than the temperature of the heating drum to about 320 ° C. somewhat higher than the temperature of the heating drum. It turned out that such a phenomenon was seen. As the thermosetting resin, a polyurethane resin is suitable because the raw material is inexpensive, the properties are stable, and the like.

The organic solvent for dispersing the pigment therein can be selected from various commercially available solvents. This formulation also affects the thermosetting temperature of the resin. Therefore, it is appropriate to realize the mixing and preparation so that the curing temperature of the thermosetting resin falls within the above range. In order to properly perform drying at a low temperature, the blending of the organic solvent is related. The optimum composition obtained by the inventor of the present invention is described in the examples below. However, it is appropriate to change and adjust the value depending on the performance of the coating apparatus or the temperature of the heating drum of a printing apparatus using paper, and cannot provide a fixed value.

Next, regarding the pigment component, white is generally convenient as a paper surface condition. Titanium dioxide (rutile) is useful as a white pigment. However, the pigment is not limited to this, and other choices are possible. That is, any material having a property of being dispersed by an organic solvent can be widely used. Further, the pigment is not limited to white, and can be variously colored according to the use of the paper. By mixing a white pigment with a small amount of coloring pigment, various papers such as light red, light green, light purple, and light blue can be provided.

The coating agent in which the pigment and the thermosetting resin are dispersed is applied as an ink to the surface of a plastic film by a conventionally known printing technique. Since it is a printing technique, it can be applied to the entire surface of a plastic film, and can also be applied partially by, for example, adding a pattern or a company logo by processing the plate cylinder.

The mixing ratio of the pigment in the coating agent is 25 to 45% by weight, preferably 30 to 40% by weight, and the mixing ratio of the thermosetting resin in the coating agent is 7 to 40% by weight, preferably 10 to 10% by weight.
It is effective that it is -20% by weight.

Since this coating material is applied by a printing technique, the viscosity of the coating material must be appropriate. It is desirable to adjust the viscosity to such an extent that it can be smoothly applied to the printing plate by the components of the organic solvent or by mixing the viscosity adjusting agent. As the viscosity adjusting agent, for example, silica or polyethylene wax can be used.
It is not limited to this. As the organic solvent, one of methyl ethyl ketone, toluene, isopropyl alcohol, and ethyl acetate, or a mixture of two or more thereof can be used.

After this coating step, the organic solvent in which the pigment applied to the surface of the plastic film is dispersed is dried at a low temperature. If the temperature is too low or the time is too short, the surface of the paper becomes sticky. On the other hand, if the temperature is too high, the organic solvent is thermally cured, and the above-described thermal curing that embraces the printed carbon particles inside becomes impossible. However, according to the results of tests conducted by the inventor, this temperature does not need to be set so strictly. Temperature 50 lower than the temperature at which the thermosetting resin is thermoset
An appropriate temperature can be found relatively easily by setting the temperature within the range of -160 ° C., changing the temperature, and performing trial and error. In the device that the inventors actually tested,
The appropriate temperature for this low-temperature drying was 50 to 100 ° C., but the optimum temperature may not always be in this range depending on the passage time in the drying passage and the preparation of the organic solvent.

Prior to printing and coating, it is desirable to roughen the surface of the plastic film by corona treatment so that the adhesive strength of the coating agent can be increased.

A second aspect of the present invention is that a thermosetting resin containing a pigment is applied to at least a part of the surface of a plastic film mainly composed of polyethylene terephthalate before the thermosetting. It is characterized by. An adhesive that does not cure at the curing temperature of the thermosetting resin is applied to the back surface of the plastic film, and a release sheet is placed over the adhesive.

That is, the thermosetting resin mixed with the pigment is applied to the surface of the plastic film before the thermosetting, and after the adhesive is applied to the back surface of the plastic film, the peeling backing sheet is applied. The plastic film is cut into various sizes, for example, a business card size, a telephone card size, a postcard size, or the like, to form a label. A figure or a character is printed on the surface by an electrostatic copying type printing machine or a copying machine, and is peeled off from the mounting sheet for use as a label. If it is used in places where water or oil is applied or where it is rubbed by hand, it does not change like paper even when wet, and characters and figures are hard to disappear even when rubbed, and can be endured for a long time.

The consultation ticket, driver's license, identification card and the like are always touched by hand, and sometimes rain water is applied.
Although some of these are already protected by a transparent film, the cost can be greatly reduced by using the plastic film according to the present invention.

[0027]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially enlarged sectional view showing the structure of the printing paper according to the embodiment of the present invention.

The printing paper of the embodiment of the present invention is obtained by using ink 1 as a coating material 1 in which a pigment and a thermosetting resin having a curing temperature of 220 to 320 ° C. are mixed and dispersed in an organic solvent, and the coating material 1 is mainly made of polyethylene terephthalate. It is applied to the surface of the plastic film 2 by printing and dried at a temperature lower than the curing temperature of the thermosetting resin. The thickness of the coating agent 1 is several μm, and the thickness of the plastic film 2 is 12 μm.
３０30 μm.

Titanium dioxide (rutile) is used as the main component of the pigment, and polyurethane resin is used as the main component of the thermosetting resin. The mixing ratio of the pigment in the coating material 1 is 25 to 45% by weight, preferably 30 to 40% by weight, and the mixing ratio of the thermosetting resin in the coating material 1 is 7 to 40%. % By weight, but preferably 10 to
It is preferably 20% by weight.

The organic solvent is one of methyl ethyl ketone, toluene, isopropyl alcohol and ethyl acetate.
Alternatively, a mixture of two or more of these is used, and a small amount of silica and / or polyethylene wax or any of them is added to an organic solvent. This adjusts the viscosity to suit the printing press.

The temperature at which the coating composition is dried is selected within the range of 50 to 160 ° C., which is lower than the curing temperature of the thermosetting resin.

As shown in FIG. 1, when the coating material 1 is applied by printing, the surface of the plastic film 2 is roughened by corona treatment to improve the adhesion.

FIG. 2 shows a main part of an apparatus for producing printing paper according to the embodiment of the present invention. The apparatus includes a coating material storage tank 3 for storing a coating material 1, a plate cylinder 4 for printing and coating a coating material on the surface of a plastic film 2 by rolling, and an extra coating material 1 from the plate cylinder 4. A doctor device 5 for scraping, a pressure roller 6 for pressing the plastic film 2 against the plate cylinder 4 with a predetermined pressure, and a thermosetting of the coating material 1 by passing the plastic film 2 on which the coating material 1 is applied by printing. Dryer 7 for drying at a temperature lower than the curing temperature of the conductive resin, cooler 8 for cooling the dried plastic film 2 and coating material 1, and a plurality of turn rolls 9 for guiding the plastic film to predetermined positions. And are provided.

Example 1 A biaxially stretched film (polyester film) having a maximum heat resistance of 264 ° C. and made of polyethylene terephthalate as a main raw material was subjected to a corona treatment and roughened. A pigment, a thermosetting resin and an organic solvent are used as a coating agent. Titanium dioxide (rutile) is used as a pigment in a proportion of 34% by weight, a polyurethane resin is used as a thermosetting resin in a proportion of 14% by weight, and methyl ethyl ketone is used as an organic solvent. Weight%, toluene 14% by weight, isopropyl alcohol 7% by weight, ethyl acetate 7% by weight,
Further, for adjusting the viscosity, 2% by weight of silica and 8% by weight of erythylene wax were prepared, and these were stirred twice using a dispersing machine sand mill to obtain a coating agent.

This coating agent is applied to a printing apparatus shown in FIG.
Change the viscosity Zan cup from 15 seconds to 18 seconds and print at 7
At 5 m / min, it was printed and applied to the surface of the plastic film and dried at a drying temperature of 50 ° C.

When electrostatic copying was performed using this printing paper, carbon particles 10 adhered to the concave portions of the coating material 1 immediately after copying, as shown in FIG. ), The carbon particles 10 were entrapped inside the coating material 1. Attempts were made to scrape this, but the copied graphics or characters remained. In addition, although writing was attempted on the coating material, it was possible as with paper, and a water-based stamp was used, but the display was clear.

Further, for comparison, printing was performed by electrostatic copying of characters or figures under exactly the same conditions using paper and the printing paper according to the present invention, and immediately thereafter, a test of wiping with a tissue paper was performed. As a result, in the case of paper, diffusion of carbon particles 10 was observed, but in the case of printing paper according to the present invention, diffusion of carbon particles 10 was not observed at all. Thus, it was proved that the granule particles 10 were securely held in the coating material 1 by the heating after the copying, and that the preservability thereof was improved.

(Embodiment 2) FIG. 4 is a perspective view showing an example of a use form of the printing paper of the present invention.

In the same manner as in Example 1, a thermosetting resin mixed with a pigment is applied to the surface of a plastic film 2 made mainly of polyethylene terephthalate before the thermosetting, and the back surface of the plastic film 2 is heated. An adhesive that does not cure at the curing temperature of the curable resin is applied, and after the adhesive is covered with a release board 11, the plastic film 2
Was subjected to multiple card-shaped notches.

Characters are printed on the card-shaped portion by electrostatic copying, and the card-shaped plastic film 2 is peeled off as shown by the arrow in FIG. did.

(Embodiment 3) FIGS. 5 (a) and 5 (b) are diagrams showing another use form of the printing paper of the present invention.

The plate cylinder 4 is processed so that the outer circumference of the printing paper is
The coating material 1 was printed so that the diamond mark pattern remained on the plastic film 2 as shown in FIG. When copying was performed on this printing paper using an electrostatic copying machine, the inside of the diamond mark was transparent because the coating material 1 was not applied, and a black diamond mark was obtained.

Further, as shown in FIG. 3B, the plate cylinder 4 was processed and the coating material 1 was printed so that characters (for example, company name) remain on the upper part of the printing paper. Similarly, when this printing paper was copied using an electrostatic copying type copying machine, the inside of the figure around the character was black because it was transparent because the coating material 1 was not applied because the coating agent 1 was not applied, and appeared white. I got the letters.

[0044]

As described above, according to the present invention, characters and figures can be printed on the surface of a plastic film using an electrostatic copying machine or a copying machine.
During the printing, the carbon particles can be hardened by embracing the carbon particles without impairing the properties of the plastic film. This makes it hard to lose even if it gets wet or rubbed, and can withstand long-term storage, so it requires long-term storage, such as blueprints, maps, land survey maps, or nameplates, signs, and posters. It can be used very effectively if used for other contracts, wills, etc.

Furthermore, since the adhesive can be applied to the back surface of the plastic film and cut out to be used as a label paper, it is possible to maintain a label display at a place where water is easily applied or rubbed for a long time. Can be.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing the structure of a printing sheet according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a main part of an apparatus for manufacturing a printing sheet according to an embodiment of the present invention.

FIG. 3A is a partially enlarged cross-sectional view showing a state in which carbon particles adhere to a coating agent immediately after electrostatic copying in Example 1 of the present invention, and FIG. FIG. 2 is a partially enlarged cross-sectional view showing a state in which the user is embraced.

FIG. 4 is a perspective view showing an example of a use form of the printing paper according to the embodiment of the present invention.

FIGS. 5A and 5B are diagrams showing another use form of the printing paper of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating agent 2 Plastic film 3 Coating agent storage tank 4 Plate cylinder 5 Doctor device 6 Pressure roller 7 Dryer 8 Cooler 9 Turn roll 10 Carbon particle 11 Peeling board

Claims (10)

[Claims] An ink is prepared by mixing and dispersing a pigment and a thermosetting resin having a curing temperature of 220 to 320 ° C. in an organic solvent, and is printed and applied on the surface of a plastic film mainly composed of polyethylene terephthalate. A method for producing printing paper, characterized by drying at a temperature lower than the temperature. 2. A main component of the pigment is titanium dioxide (rutile), a main component of the thermosetting resin is a polyurethane resin, and a mixing ratio of the pigment in the coating agent is 25.
The method for producing printing paper according to claim 1, wherein the mixing ratio of the thermosetting resin in the coating agent is 7 to 40% by weight. 3. The method according to claim 2, wherein the mixing ratio of the pigment is 30 to 40% by weight, and the mixing ratio of the thermosetting resin is 10 to 20% by weight. 4. The method according to claim 1, wherein the organic solvent is one of methyl ethyl ketone, toluene, isopropyl alcohol, and ethyl acetate, or a mixture of two or more thereof. 5. The method for producing printing paper according to claim 4, wherein a small amount of silica and / or polyethylene wax is added to said organic solvent to adjust the viscosity so as to be compatible with a printing machine. 6. The temperature lower than the curing temperature is 50-16.
The method for producing printing paper according to claim 1, wherein the temperature is 0 ° C. 7. The method for producing printing paper according to claim 1, wherein the surface of the plastic film is roughened before printing. 8. The method for producing printing paper according to claim 7, wherein said roughening is corona treatment. 9. A printing paper characterized in that a thermosetting resin mixed with a pigment is applied to at least a part of the surface of a plastic film mainly composed of polyethylene terephthalate before thermosetting. 10. The printing paper according to claim 9, wherein an adhesive that does not cure at the curing temperature of the thermosetting resin is applied to the back surface, and the adhesive is covered with a release sheet.