JPH11229297A - Modifying treatment of papers and modified papers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for carrying out the modifying treatment of the whole layer even to the inner layer of a paper by which diversified small-lot treatment can be carried out without requiring a drying step or a waste liquor treatment and to obtain modified papers of good quality recyclable as recycled papers without heat deterioration, or the like. SOLUTION: A material to be treated of a paper substrate 5 containing voids among pulp fibers constituting the paper filled with a reactional gas consisting essentially of an inert gas such as helium is passed through a spacing between opposing electrodes 1 and 2 in which the surface of at least one electrode is covered with a solid dielectric 3 and placed between the electrodes l and 2. In this state of the material to be treated of the paper substrate 5, a high voltage is applied to the electrode 2 to produce a plasma discharge obtained by an applied voltage at 500 Hz to 1 MHz in the interior of the material to be treated of the paper substrate 5. Otherwise, the plasma discharge is produced in the material to be treated of the paper substrate 5 while replacing the voids among the pulp fibers constituting the paper with the reactional gas consisting essentially of the inert gas in the state of the material to be treated of the paper substrate 5 placed between the electrodes 1 and 2. Thereby, the modifying treatment of the whole layer of the material to be treated of the paper substrate 5 is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying all the layers on the surface and the inner surface of paper and a paper modified on the surface and the inner surface.

[0002]

2. Description of the Related Art Conventionally, paper, paperboard, Japanese paper, synthetic paper,
Paper such as synthetic fiber paper is used for packaging, industrial materials, clothing,
It is used for building materials and a wide range of applications.
Water resistance, water repellency, water absorption, abrasion resistance, oil resistance, heat resistance,
It has a wide variety of hot water and weather resistance. Methods for imparting these functions to papers are broadly classified into a method in which the function is performed in a papermaking process called a wet end process and a method in which the function is performed as post-processing on the formed paper.

[0003] The former wet process includes internal addition of a chemical to a pulp slurry before papermaking to fix the pulp, and application of a chemical in a finishing part of papermaking. These agents include sizing agents such as rosin, wax and alkyl ketene dimer, paper strength agents such as urea resin, melamine resin, polyacrylamide, starch, etc., clay, calcium carbonate, etc., dyes, etc. .

However, when imparting a function to paper in the above wet end process, the added chemical must be water-based, and the yield of a chemical having a low affinity for pulp fibers is poor. In addition, since the paper machine is a very large device and uses a large amount of water, the running cost greatly affects the production of a small lot. Therefore, in order to provide various functions in a small lot, a processing method in a wet end process is not suitable.

On the other hand, in the case of imparting functions to paper as the latter post-processing, it is possible to impart functions according to the intended use only in a necessary amount from a large amount of paper-making paper. Suitable for. As a general method by the post-processing, a roll coating method or a bar coating method, a gravure coating method, a coating method of a drug using an air knife, or an impregnation method of immersing the drug in a drug solution to fix the drug in a paper substrate, and the like. Also, there is a method such as corona discharge treatment or flame treatment that does not use a liquid chemical.

[0006] However, the above coating and impregnation can be used by dissolving various chemicals in a solvent.
Although various functions can be provided, a drying step is required because a solvent is used, and high heat energy is required. Further, in the case of an organic solvent, there is a problem that the treatment of exhaust gas and waste liquid leads to environmental destruction.

On the other hand, in the above-described corona discharge treatment and flame treatment, there is no problem with the amount of drying heat or waste liquid, but the reforming effect is low.
It cannot be said that various functions are provided. Generally, it is used for the purpose of improving printability and wettability of the paper surface. Further, not only the flame but also the corona discharge tend to generate heat, and the processing output of a substrate that is weak to heat is limited.

Therefore, recently, glow discharge plasma processing has attracted attention. Glow discharge is a non-thermal equilibrium plasma,
Although high-density processing at a low temperature is possible, a spark was conventionally generated at atmospheric pressure, and a stable glow discharge could not be obtained without vacuum. Therefore, it has not been widely applied to a base material containing a large amount of moisture and impurities, such as paper, and is difficult to maintain a vacuum. However, in recent years, using a high-frequency power supply, at least one surface of the opposing electrodes is covered with a dielectric to prevent the occurrence of sparks, and the space between the electrodes is filled with an inert gas atmosphere, thereby extending the plasma life even at atmospheric pressure. As a result, stable atmospheric pressure glow discharge plasma can be obtained. For example, Japanese Patent Application Laid-Open No. 5-9897 proposes a method of performing surface treatment on papers such as modified papers using such an atmospheric pressure glow discharge. Also,
As shown in Japanese Patent No. 2517771, in an atmospheric pressure plasma treatment, various functions such as hydrophobicity, hydrophilicity, water repellency, and friction resistance can be imparted by causing discharge in various atmosphere gases. .

Considering the functions required of the paper once again, printability, wettability, water repellency, etc. can be achieved only by modifying the paper surface, but the strength, water resistance, water absorption, etc. It cannot be said that surface modification alone is sufficient. In other words, it is necessary to modify all the layers up to the inside of the paper substrate. In order to modify all layers up to the inside of the paper substrate, the conventional method is limited to internal addition or impregnation. As described above, in the case of internal addition, it is not suitable for small lots, and in the case of impregnation, in addition to the drying problem described above, a large amount of chemicals is required to impregnate the chemicals into all layers of the paper base material. Is also a problem. In other words, in addition to the problem of drug cost, there is also a problem that a drug contained in a large amount in paper hinders recycling of paper as recycled paper.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to perform various processes in small lots without requiring a drying step or waste liquid treatment. Another object of the present invention is to provide a method of reforming all layers over the surface and the inner surface of papers and to provide high quality modified papers which can be recycled as recycled paper and have no thermal deterioration.

[0011]

In order to achieve the above-mentioned object in the present invention, first, according to the first aspect of the present invention, the voids between pulp fibers constituting paper are filled with a reactive gas mainly composed of an inert gas. The filled paper substrate to be processed is passed between opposed electrodes having at least one electrode surface covered with a solid dielectric, and a high voltage is applied to the electrodes while being placed between the electrodes to be processed. A method for modifying paper is characterized in that a plasma discharge is generated inside a base paper substrate, and all layers from the surface to the inner surface of the object to be treated are modified.

According to the second aspect of the present invention, the paper substrate to be processed is passed between opposed electrodes whose at least one electrode surface is covered with a solid dielectric, and the paper is placed between the electrodes. A plasma discharge is generated inside the paper substrate to be treated while replacing the voids between the constituent pulp fibers with a reaction gas mainly composed of an inert gas, and all layers are formed from the surface to the inner surface of the paper substrate to be treated. In which a paper is modified.

According to a third aspect of the present invention, there is provided the paper reforming method according to the first or second aspect, wherein the reactive gas is mainly helium, argon, or neon gas. is there.

According to the present invention, the plasma discharge is obtained by applying a high voltage having a frequency of 500 Hz to 1 MHz. It is a processing method.

According to a fifth aspect of the present invention, the plasma discharge is obtained by applying a high voltage of a DC pulse having a pulse width of 10 μsec or less. A method for modifying paper as described above.

According to a sixth aspect of the present invention, there is provided a modified paper treated by the paper modifying method according to the first, second, third, fourth or fifth aspect.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the apparatus used in the method for modifying papers of the present invention has a ceramic solid dielectric (3) fixed to the upper part of a grounded flat electrode (1). A flat plate-shaped voltage applying electrode (2) facing in parallel with this has a surface made of ceramic solid dielectric (3).
The voltage applying electrode (2) is electrically connected to a power supply (4) capable of generating a high voltage having a frequency of 500 Hz to 1 MHz.

According to the present invention, the space between the pulp fibers constituting the paper is formed between the two electrodes (1 and 2) of the reforming treatment apparatus by using a reactive gas mainly containing an inert gas to impart a function to the paper. Filling the treated paper base material (5) with the treated paper base material (5)
The distance from the surface to the voltage application electrode (2) is set to, for example, about 2 mm, a high voltage is applied to the voltage application electrode (2), and a plasma discharge is generated inside the paper substrate (5) to be processed. This is a method of modifying paper, in which all the layers from the surface to the inner surface of the paper substrate to be treated are generated and modified.

In another aspect of the present invention, the paper substrate to be processed (5) is placed between the two electrodes (1, 2) of the reforming apparatus from the surface of the paper substrate to be processed (5). The plate is placed with the distance to the voltage applying electrode (2) of, for example, about 2 mm, and the gap between the pulp fibers constituting the paper is replaced with a reaction gas that imparts a function to the paper mainly composed of inert gas. A high voltage is applied to the flat plate type voltage application electrode (2) to generate plasma discharge inside the paper substrate (5) to be processed, and all layers from the surface to the inner surface of the paper substrate (5) to be processed This is a method of modifying paper for treating paper.

As another apparatus of the paper reforming method of the present invention, as shown in FIG. 2, a ceramic solid dielectric (3) is provided above a grounded flat electrode (1). Is fixed, and a knife-edge-type voltage applying electrode (6) opposed thereto is provided. Further, the knife-edge-type voltage applying electrode (6) is provided with a DC pulse having a narrow pulse width. It is electrically connected to a power supply (7) capable of generating a voltage. Although not shown in the drawing, a mechanism for moving the paper substrate (5) to be processed in the vertical direction of the knife-edge type voltage applying electrode (6) is provided, so that a uniform reforming in the flow direction is provided. It is devised so that processing is possible.

According to the present invention, the space between the pulp fibers constituting the paper between the two electrodes (1, 6) of the reformer shown in FIG. 2 is filled with a reactive gas mainly composed of an inert gas. The paper substrate to be processed (5) is placed with the distance from the surface of the paper substrate to be processed (5) to the knife-edge type voltage applying electrode (6) being, for example, about 3 mm. A high voltage is applied to the voltage application electrode (6), and the paper substrate (5) to be processed is applied.
This is a method for modifying paper, in which a plasma discharge is generated inside the substrate and all layers extending from the surface to the inner surface of the paper substrate to be treated (5) are modified.

In another aspect of the present invention, a paper substrate to be processed (5) is provided between the two electrodes (1, 6) of the reforming apparatus. And the knife-edge voltage applying electrode (6) is placed at a distance of, for example, about 3 mm, and the gap between the pulp fibers constituting the paper is replaced with a reactive gas mainly containing an inert gas to impart a function to the paper. While applying a high voltage to the knife-edge type voltage applying electrode (6),
This is a paper modification treatment method in which a plasma discharge is generated inside the treated paper base material (5), and the entire layer from the surface to the inner surface of the treated paper base material (5) is modified.

As still another apparatus of the paper reforming method of the present invention, as shown in FIG. 3, a ceramic solid dielectric (3) is placed on the grounded flat electrode (1). ) Is fixed, and a flat container (10) having a member having a plurality of holes for allowing gas to pass therethrough is disposed above the solid dielectric (3). The flat container (10) is provided with a means (not shown) capable of exhausting air from the space in the container to the outside (not shown), and a plurality of holes for allowing gas to pass therethrough on the upper surface of the flat container (10) allow external air to pass therethrough. It is a mechanism that can suck. A paper substrate to be processed (5) is placed in contact with a member having a plurality of holes for allowing gas to pass therethrough on the upper surface of the flat container (10). Further, a nozzle (9) for supplying a reactive gas, an example of which is shown in FIG. 4, is provided in the form close to the upper surface of the paper substrate (5) to be processed.
The reactive gas is supplied from the nozzle (9) to the paper substrate (5) to be treated.
The reaction gas is supplied above and exhausts the space in the flat container (10) below the paper substrate (5) to be processed, so that the reaction gas passes through the flat container (10) through the paper substrate (5) to be processed. ). Therefore, the voids between the pulp fibers in the paper substrate (5) to be treated are filled with the reactive gas. Further, the nozzle (9)
A multi-needle voltage applying electrode (8) whose surface is covered with a ceramic solid dielectric (3) is provided above and above the grounded flat electrode (1) in parallel. . The multi-needle voltage applying electrode (8) is electrically connected to a power supply (4) capable of generating a high voltage having a frequency of 500 Hz to 1 MHz.

According to the present invention, there is provided a flat container (10) between the two electrodes (1, 8) of the reforming apparatus shown in FIG.
Paper substrate to be treated (5) in which voids between pulp fibers constituting paper are filled with a reactive gas mainly composed of inert gas
Is placed, and a high voltage is applied to the multi-needle voltage applying electrode (8) to generate a plasma discharge inside the processing target paper base material (5). ) Is a method for modifying papers in which all layers from the surface to the inner surface are modified.

In another aspect of the present invention, a paper substrate to be processed (5) is placed between the two electrodes (1, 8) of the above-mentioned reforming treatment apparatus, and the pulp fibers constituting the paper are interposed. A high voltage is applied to the multi-needle voltage applying electrode (8) while replacing the voids with a reaction gas that imparts a function to the paper mainly composed of an inert gas, and the inside of the paper substrate (5) is processed. This is a method for modifying paper, in which a plasma discharge is generated and the entire layer from the surface to the inner surface of the paper substrate to be treated (5) is modified.

Here, the materials and the conditions for the reforming treatment according to the present invention will be described in detail. According to the present invention, when the paper substrate is exposed to atmospheric pressure plasma discharge, the surface of the paper substrate is modified, and an inert gas is positively incorporated into the paper substrate.
When the voids between the pulp fibers are filled with an inert gas, plasma discharge is also generated inside the paper base material, and the reforming treatment is performed on all layers up to the inside of the paper base material.

Helium, argon, neon, or a mixed gas thereof can be used as the inert gas. Among them, helium gas is most preferable because it can generate stable atmospheric pressure plasma. However, with the use of the inert gas alone, even if the atmospheric pressure plasma treatment is performed, the hydrophilicity is only slightly improved, but various functions can be imparted by adding various gases according to the required performance. . There is no particular limitation on the type of gas to be added, and other than inorganic gas, organic gas, reactive monomer gas, and may be added by spraying a solution,
It may be a mixed gas of several kinds of gases. However, the inert gas must be mainly used, and the amount of the additive gas is preferably suppressed to 20% by volume or less.

For example, when it is desired to improve the hydrophobicity to impart water resistance and water repellency, the additional gas of the reaction gas may be a fluorinated gas such as CF ₄ or C ₂ F ₆ , ethylene or propylene. And unsaturated aliphatic hydrocarbon gases such as propane, butane, heptane and hexane. In addition, when it is desired to improve the hydrophilicity and impart water absorption, for example, oxygen, carbon dioxide, ammonia gas, methanol, ethanol, alcohols such as isopropyl alcohol, acetone, ketones such as methyl ethyl ketone and the like are added. Good.

In the present invention, the method of replacing the voids between the pulp fibers of the paper base material to be treated with the above-mentioned reaction gas is not particularly limited, and the basis weight of the paper base material (5) to be treated is It can be appropriately selected according to properties such as bulk density and the like. As an example of the replacement method, a method of introducing a reaction gas after deaeration of the gap between pulp fibers of the paper substrate to be treated (5), or a method of introducing a reaction gas to one side of the paper substrate to be treated (5) A positive pressure atmosphere, and the other side is a negative pressure atmosphere provided with an exhaust means. For example, a method of forcibly blowing a reaction gas into the gap between the pulp fibers of the paper base material to be treated (5) is used. The voids can be filled with the above-mentioned inert gas-based reaction gas.

The gas replacement of the paper substrate to be treated (5) may be performed, for example, before placing the paper substrate to be treated (5) between the opposed electrodes (1, 2). It may be performed between the above-mentioned opposed electrodes (1, 2) to which a high voltage is applied. However, in the former, before the reaction gas in the paper substrate to be treated (5) is diffused into the air, the gas is immediately placed between the electrodes (1, 2) after the gas replacement, and It is preferable to apply a high pressure to the substrate. On the other hand, when the reactive gas is replaced in the paper substrate (5) to be treated between the electrodes to which the high voltage is applied, the loss due to the diffusion of the reactive gas is small, so that a more effective reforming treatment is performed. It is possible.

The electrode of the present invention is an opposed parallel plate type voltage applying electrode (2), or one is a plate type grounded electrode (1) and the other is a multi-needle type voltage applying electrode (8). Alternatively, it is preferable to use a knife-edge type voltage application electrode (6) or a mesh electrode. Further, by covering at least one electrode surface with the solid dielectric (3), the discharge is prevented from being concentrated at one point and shifting to arc discharge. When the distance between the two electrodes is as narrow as possible, the electric field strength of the plasma increases, and a high reforming effect can be obtained. Therefore, the distance from the object to be processed to both electrodes is preferably 5 mm or less or in contact with each other. Further, one electrode is a ground electrode (1) and the other electrode is a voltage application electrode (2, 6,.
8) and a mechanism for applying a high voltage is preferable.

The power supply of the present invention is a high-voltage power supply (500 Hz to 1 MHz, preferably 1 KHz to 10 KHz) in order to generate a low-temperature plasma that does not generate an arc even at atmospheric pressure and generates little heat. 4) Alternatively, a high voltage power supply (7) of a DC pulse having a narrow pulse width, preferably a DC pulse having a pulse width of 10 μsec or less is preferably used. This is because a power supply in a low-frequency range of 500 Hz or less has a small reforming effect, and a high-frequency power supply of 1 MHz or more or a DC pulse power supply with a pulse width of 10 μs or more generates heat and damages an object to be processed. Further, when a DC pulse power supply having a pulse width of 10 μsec or less is used, it is preferable to apply a high-voltage DC pulse at a pulse frequency of 30 to 1000 pulses per second. At 30 pulses / sec or less, the reforming effect is small, and at 1000 pulses / sec or more, the effect of heat appears.

Further, in the present invention, the applied voltage, the processing time and the like are appropriately set according to the properties and processing area of the paper substrate (5) to be processed, the required reforming level, the type of the reaction gas, the electrodes and the power supply. And there is no particular limitation.

The papers of the present invention include paper, paperboard, Japanese paper, synthetic paper, synthetic fiber paper, and the like, which are used for a wide range of applications such as packaging, industrial materials, clothing, and building materials. The paper may be 100% pulp or may contain recycled paper, and is not particularly limited. In addition, as long as the paper can be recycled, the paper may be coated with a small amount of chemicals and impregnated. It is more preferable that the paper is bulky and has a large gap between the pulp fibers because the reaction gas can be easily replaced.

By using the method for modifying papers of the present invention as described above, stable low-temperature plasma can be generated inside the paper substrate (5) to be processed without generating heat. Further, in the conventional corona discharge treatment or atmospheric pressure plasma treatment, only the surface of the target paper substrate (5) is modified, whereas the surface of the target paper substrate (5) is not positively modified. By blowing a reactive gas mainly composed of an active gas and filling the voids between the pulp fibers constituting the paper with the reactive gas mainly composed of an inert gas, the entire surface from the surface of the paper base material to be treated (5) to the inner surface is covered. The layer is modified. By controlling the composition of the reaction gas, various functions can be easily imparted with reforming.

Further, since the modified papers of the present invention are modified not only on the surface but also on all layers, those subjected to the hydrophobizing treatment have increased wet strength to the base paper, and have improved water resistance and strength. In the case of the one subjected to the hydrophilic treatment, the penetration distance of water to the base paper is increased, and the water absorption is improved. Further, it is a modified paper which is not deteriorated by heat as seen in corona-treated paper.

[0037]

Next, the present invention will be described more specifically with reference to examples. <Example 1> After sufficiently degassing a cardboard having a basis weight of 500 g / m ² and a thickness of 720 µm in a vacuum chamber and injecting a reaction gas, the gap between the pulp fibers constituting the paper was filled with the reaction gas. A paper substrate (5) to be treated was obtained. As a reaction gas at this time, a mixed gas containing 93% by volume of helium and 7% by volume of ammonia gas was used. As shown in FIG. 1, immediately after being filled with the reaction gas, the paper substrate (5) to be treated obtained above is placed between the two electrodes (1, 2), and the flat plate-shaped voltage applying electrode (2) is placed. ) To 5KV at 1KHz frequency
Was applied for 60 seconds.

<Example 2> Reforming was carried out in the same manner as in Example 1 except that the composition of the reaction gas in Example 1 was 60% by volume of helium, 35% by volume of neon, 5% by volume of propylene, and the frequency of the applied voltage was 10 KHz. Processing was performed.

Example 3 Basis weight 500 g / m ² , thickness 7
After sufficiently degassing a 20 μm cardboard in a vacuum chamber and injecting the reaction gas, the gap between the pulp fibers constituting the paper is filled with the reaction gas, and the paper substrate to be treated (5)
I got As a reaction gas at this time, a mixed gas containing 90% by volume of argon, 8% by volume of acetone, and 2% by volume of carbon dioxide was used. As shown in FIG. 2, immediately after being filled with the reaction gas, the paper substrate to be treated (5) obtained above is placed between the two electrodes (1, 6), and a knife-edge type voltage application electrode is applied. In (6), a DC pulse having a pulse width of 2 μsec was applied at a pulse frequency of 200 pulses / sec and a voltage of 70 KV was applied for 30 sec.

Example 4 A basis weight of 500 g / m ² and a thickness of 7
20 μm of cardboard was used as the paper substrate (5) to be treated, and FIG.
Is disposed in contact with the upper surface of a flat container (10) having a member having a plurality of holes for allowing gas to pass therethrough, as an upper surface,
The reaction gas was supplied from the nozzle (9). The composition of the reaction gas was 82 vol% helium, 12.5 vol% nitrogen, 5 vol% oxygen, and 0.5 vol% ethanol. The multi-needle voltage applying electrode (8) is evacuated from the flat container (10) to fill the gap between the pulp fibers of the target paper base material (5) with the reaction gas while reacting the reaction gas with the reaction gas. A voltage of 5 KV at a frequency was applied for 20 seconds.

Example 5 The paper substrate to be treated (5) in Example 4 was kraft paper having a basis weight of 400 g / m ² and a thickness of 520 μm.
A reforming treatment was performed in the same manner as in Example 4 except that CF ₄ was changed to 3% by volume.

Comparative Example 1 A reforming treatment was performed in the same manner as in Example 1 except that the frequency of the applied voltage was changed to 480 Hz.

Comparative Example 2 A reforming process was performed in the same manner as in Example 2 except that the frequency of the applied voltage was 13.56 MHz.

Comparative Example 3 A reforming process was performed in the same manner as in Example 3 except that the pulse width of the applied DC pulse voltage was changed to 15 μs and the pulse frequency was changed to 1000 pulses / second.

<Comparative Example 4> In Comparative Example 4, except that all the holes on the upper surface of the flat container (10) having a member having a plurality of holes for gas permeation shown in FIG. Was subjected to a reforming treatment in the same manner as in Example 4. That is, the reaction gas is supplied to the space between the electrodes (1 and 8), but the reforming treatment is performed in a state where the reaction gas is not replaced up to the gap between the pulp fibers of the paper substrate (5). Was.

Comparative Example 5 Basis weight 400 g / m ² , thickness 5
20 Km kraft paper was used as the substrate paper (5) to be processed, and an output of 1 KW generated from a high-frequency power supply having a frequency of 10 kHz
For 20 seconds by corona discharge.

The papers modified in the above Examples and Comparative Examples were observed for changes in appearance, left in an environment of 20 ° C. and 65% RH for 24 hours, and formed into strips of 15 mm width.
The test piece was only in the longitudinal direction of the paper. The test piece was immersed in distilled water for 10 minutes, and the wet tensile strength was measured. The ratio of wet strength to ordinary tensile strength not immersed in distilled water was used as an index of water resistance. That is, wet strength / normal strength (%) was calculated and evaluated. Further, the test piece is held vertically, immersed in distilled water by 5 mm, and the height of the water rising in the paper for 1 minute,
That is, the permeation distance was measured and used as an index of water absorption. The results are shown in Table 1.

[0048]

[Table 1]

From Table 1 above, the papers obtained in Examples 1 to 5 have been subjected to the modification treatment from the surface to the inner surface of the paper base material (5) to be treated, and have been deteriorated by heat. And so on. On the other hand, the papers obtained in Comparative Examples 1 to 5 were deteriorated by heat or provided with a desired function did not reach the inner surface of the paper substrate (5).

[0050]

As described above, the present invention has the following effects. That is, a paper substrate to be processed, in which voids between pulp fibers constituting paper are filled with a reactive gas mainly composed of an inert gas, is passed between opposed electrodes having at least one electrode surface covered with a solid dielectric. In the state of being placed between the electrodes, a high voltage is applied to the electrodes to generate plasma discharge inside the paper substrate to be processed, and the entire layer from the surface to the inner surface of the processing object is reformed. Alternatively, while the paper substrate to be treated is placed between the two electrodes, the gap between the pulp fibers constituting the paper is replaced with a reaction gas mainly composed of an inert gas, while the paper substrate to be treated is A method of modifying paper, which generates a plasma discharge inside the paper and modifies all layers from the surface to the inner surface of the paper substrate to be processed, enables small lot multi-processing, drying process and waste liquid No processing required,
All layers of paper can be modified.

The reaction gas is mainly composed of helium, argon, or neon gas, and the plasma discharge is performed by applying an AC voltage having a frequency of 500 Hz to 1 MHz or a DC pulse having a pulse width of 10 μsec or less. Thus, the obtained modified papers can be made of good quality without thermal deterioration or the like.

Also, unlike modified papers by coating or impregnation, it can be recycled as recycled paper. Therefore, the present invention exhibits excellent practical effects in applications such as packaging paper as papers having various functions.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a paper reforming treatment method of the present invention.

FIG. 2 is a schematic view illustrating another embodiment of the paper reforming method of the present invention.

FIG. 3 is a schematic view showing still another embodiment of the paper reforming method of the present invention.

FIG. 4 is a schematic view showing an embodiment of a reactive gas supply nozzle used for the paper reforming process of the present invention.

[Description of Signs] 1) Grounded flat-plate electrode 2) Flat-plate voltage application electrode 3 Solid dielectric 4 Power supply capable of generating high voltage of 500 Hz to 1 MHz frequency 5 Processed Body paper substrate 6 Knife-edge type voltage applying electrode 7 # Power supply that can generate high voltage of DC pulse with narrow pulse width 8 # Multi-needle type voltage applying electrode 9 # Reactive gas supply nozzle 10 # ‥ Flat container

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Kawasaki 1-5-1, Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Kentaro Yamawaki 1-15-1 Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd.

Claims (6)

[Claims] An opposed electrode in which at least one electrode surface is covered with a solid dielectric material on a paper substrate to be treated in which a space between pulp fibers constituting paper is filled with a reactive gas mainly composed of an inert gas. In the state of being placed between the electrodes, a high voltage is applied to the electrodes to generate plasma discharge inside the paper substrate to be processed, and all the layers from the surface to the inner surface of the processing object are reformed. A method for improving the quality of paper, characterized by performing a quality treatment. 2. A gap between pulp fibers constituting a paper in a state in which a paper substrate to be processed is passed between opposed electrodes each having at least one electrode surface covered with a solid dielectric and placed between the electrodes. Generating a plasma discharge inside the paper substrate to be treated while substituting with a reactive gas mainly composed of an inert gas, and reforming all layers from the surface to the inner surface of the paper substrate to be treated. Characteristic paper modification treatment method. 3. The reaction gas according to claim 1, wherein the reaction gas is mainly helium, argon, or neon gas.
Or the method for modifying papers according to 2. 4. The plasma discharge has a frequency of 500 Hz to 500 Hz.
4. The method for modifying papers according to claim 1, wherein the method is obtained by applying a high voltage of 1 MHz. 5. The paper reforming method according to claim 1, wherein said plasma discharge is obtained by applying a high voltage of a DC pulse having a pulse width of 10 μsec or less. Processing method. 6. A modified paper treated by the method for modifying paper according to claim 1, 2, 3, 4, or 5.