JP2001183862A - Method for producing recyclable recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a recyclable recording material by which a recording material whose image removing performance lowers hardly even when it is allowed to stand for a long period of time in a humid environment is obtained without causing yellowing. SOLUTION: A coating solution for a surface layer containing at least a water-soluble resin is applied on a base layer or a middle adhesive layer and the water-soluble resin is crosslinked by heating to produce the objective recyclable recording material. The crosslinking by heating is carried out in such a state of the surface layer that the residual water content per unit weight after heating at 70 deg.C for 30 min is adjusted to >=0.1 W when the water content per unit weight after the uncrosslinked recording material is allowed to stand in an environment at 25 deg.C and 85% RH is represented by W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a recording material which can remove printing material adhering to the recording material from the recording material by forming an image with a copying machine, a printer or the like, and can reuse the recording material repeatedly. About the method. In particular, the present invention relates to a method for manufacturing a recording material suitable for a removing means by physical rubbing force such as a brushing method using an aqueous solvent such as water.

[0002]

2. Description of the Related Art Today, electrophotographic copying (so-called copying) techniques using toner have become widespread, and recording materials such as paper and OHP sheets have been used in large quantities.

[0003] Printing materials printed or copied on such a recording material cannot be easily removed, and since such technology has not been put into practical use, printed matter generated in large quantities in offices is unnecessary. The reality is that they are just discarded.

It is obvious that this is not preferable for environmental protection and resource protection. Therefore, techniques for regenerating or recycling the recording material to be discarded are being actively studied. For example, in Japanese Patent Application Laid-Open Nos. 11-21855 and 6-222604, a swelling layer that swells with water is formed on the surface of a recording material, and the swelling layer is wetted with water and swelled. Discloses a technique for removing an image recorded on a recording material.

The swelling layer formed on the recording material disclosed in the above publication is obtained by applying a resin solution containing a water-soluble resin to the surface of the recording material, and heating and crosslinking the water-soluble resin. In particular, at the time of crosslinking, it is general that the recording material is directly heated in a state where the surface layer is directly in contact with the surrounding atmosphere.

[0006]

However, it has been found that when a recording material is manufactured by such a method, there is no problem in the initial performance or the repetition performance, but there may be a problem in storage stability. That is, it has been found that when a recording material manufactured by a conventional method is left for a long period of time, the ability to remove an image is significantly reduced. In particular, when the recording material was left in a high humidity environment, the image removal performance (removal of ink) was remarkably reduced.

Therefore, when the inventors of the present invention increase the crosslinking conditions (time, temperature, etc.), it is possible to obtain a recording material in which the image removing performance is hardly deteriorated even when left in a high-humidity environment for a long time. However, a new problem has arisen in that the obtained recording material is colored, especially yellowish, and the whiteness and transparency (OHP translucency) are deteriorated. If the whiteness of the recording material deteriorates, there arises a problem that an accurate color cannot be reproduced at the time of color copying, and further, the texture as paper is impaired.

The present invention has been made in view of the above circumstances, and it is possible to obtain a recording material whose image removal performance is hardly deteriorated even when left for a long time in a high humidity environment without causing yellowing. It is an object of the present invention to provide a method of manufacturing a recyclable recording material that can be used.

[0009]

According to the present invention, there is provided a recyclable method in which a coating solution for a surface layer containing at least a water-soluble resin is applied onto a base material layer or an intermediate adhesive layer, and the water-soluble resin is crosslinked by heating. A method for producing a recording material, wherein when the recording material before crosslinking is left in an environment of 25 ° C./85% RH, the water content per unit weight is W, and the recording material is heated at 70 ° C. for 30 minutes. The present invention relates to a method for producing a recording material, characterized in that heat crosslinking is performed in a surface state such that the residual moisture content per unit weight of the resin is 0.1 W or more.

The inventors of the present invention pay attention to the evaporation rate of water in the surface layer at the time of cross-linking. It has been found that it can be obtained without causing yellowing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a recording material according to the present invention, first, a surface layer coating solution containing at least a water-soluble resin is applied on a base material layer.

The base material layer is preferably a water-resistant (strength), transparent plastic film or a plastic film made opaque by adding inorganic fine particles. The material of the plastic film is not particularly limited, but polyester, polycarbonate, polyimide, polymethyl methacrylate and the like are preferable in consideration of heat resistance and the like. Further, considering versatility, price, heat resistance, durability and the like, polyester, especially polyethylene terephthalate (PE)
T), polyethylene naphthalate (PEN) and the like are desirable. It is also possible to use various sheets available as OHP. In addition, so-called synthetic paper such as paper based on plastic and paper made of plastic fiber such as PET fiber is also commercially available, and such synthetic paper is also useful as a base material. Besides this, metal foil,
Pulp paper, paper having improved water resistance, and composite materials such as resin, paper, and metal can also be used. In short, any material can be used as long as it can maintain flatness through printing and removal of the printing material, and has appropriate water resistance and appropriate mechanical strength.

For the purpose of improving the adhesion between the substrate layer and the surface layer, the surface of the substrate layer on which the surface layer is formed may be subjected to a corona discharge treatment.

The coating solution for the surface layer contains at least a water-soluble resin,
It is an aqueous solution dissolved in a suitable aqueous medium such as water or a mixed solvent of water and an aqueous organic solvent, and optionally contains a crosslinking agent and a crosslinking initiator. As the water-soluble resin, a hydroxyl group, an amino group, an amide group, a thiol group, a carboxyl group, a water-soluble resin having a functional group having an active hydrogen such as a sulfonic acid group in the molecule, for example, polyvinyl alcohol, methyl cellulose, polyacrylic acid, Carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, polyacrylamide, diacetone acrylamide, polyethylene oxide and the like can be used. Preferably, polyvinyl alcohol, methyl cellulose, or polyacrylic acid is used, and among them, polyvinyl alcohol having many hydroxyl groups is more preferable.

The degree of polymerization of the water-soluble resin is 200 to 5000,
Preferably, it is 300 to 3000. Such a water-soluble resin is used in an amount of 2 to 3 with respect to 100 parts by weight of the aqueous medium.
It is suitable to use 0 parts by weight, preferably 5 to 10 parts by weight dissolved.

Further, an ion-modified resin may be used as the water-soluble resin. Here, ionic modification refers to imparting ionicity to at least a part of the functional groups of the water-soluble resin. By ion-modifying the water-soluble resin in this manner, the hydrophilicity of the water-soluble resin can be improved, and the water absorption of the obtained surface layer can be improved, and the swelling speed of the surface layer can be increased. The functional group provided with ionicity may be any of an anionic functional group and a cationic functional group. The anionic functional group is not particularly limited as long as it is an anionic functional group,
For example, active hydrogen was replaced with a metal-substituted carboxyl group, sulfonic acid group, or hydroxyl group, and the active hydrogen of the above functional group was substituted with a substituent having a carboxyl group or a sulfonic acid group in which the active hydrogen was substituted with a metal at the terminal. And the like.
The cationic functional group is not particularly limited as long as it is a functional group having a cationic property.For example, a quaternary salified amino group, substitution of an active hydrogen of the above functional group with a quaternary salified amino group at the terminal. And those substituted with a group.

A crosslinking agent is preferably added to the surface layer coating liquid. This is because the water-soluble resin is efficiently crosslinked. As a crosslinking agent, a functional group present in the water-soluble resin molecule,
For example, there is no particular limitation as long as it has reactivity with a hydroxyl group, an amino group, an amide group, a thiol group, a carboxyl group, a sulfonic acid group and the like and can crosslink the water-soluble resin, and a known crosslinking agent is used. For example, epoxy compounds, isocyanate compounds, dialdehyde compounds, methylol compounds, melamine resins, dicarboxylic acid compounds, aziridine compounds,
And dihydrazide compounds.

Examples of the epoxy compound include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerin polyglycidyl ether, sorbitan polyglycidyl ether, and polyglycerol polyglycidyl ether. In addition to these, various epoxy compounds can be used.

As the isocyanate compound, those having two or more isocyanate groups in one molecule can be used. By using a compound having a plurality of isocyanate groups, the water-soluble resin can be efficiently crosslinked. Such isocyanates include, for example, 4,4′-
Diphenylmethane diisocyanate, 4,4'-methylenebiscyclohexyl isocyanate, tris (p-isocyanatophenyl) thiophosphate, tris (p-isocyanatophenyl) methane, trimethylolpropane tolylene diisocyanate triadduct, hydrophilic group in the molecule And the like. In addition, the isocyanate used in the present embodiment including these compounds may be protected with phenol, sulfurous acid and the like.

Examples of the dialdehyde compound include glyoxal, glutaraldehyde and the like. In addition to these, various dialdehyde compounds can be used.

Examples of the methylol compound include methylolated melamine such as dimethylolmelamine and trimethylolmelamine, dimethylolated urea, and melamine-formaldehyde resin. In addition to these, various methylol compounds can be used.

As the dicarboxylic acid compound, for example,
Oxalic acid, malonic acid, succinic acid, glutaric acid and the like can be used. In addition to these, various dicarboxylic acid compounds can be used.

Examples of the aziridine compound include diphenylmethane-bis-4,4'-N, N'-diethyl urea and 2,2'-bishydroxymethylbutanol-tris- [3- (1-aziridinyl) propinate]. Can be used. Further, an oxazoline group-containing polymer can also be used.

As the dihydrazide compound, for example, adipic dihydrazide and the like can be used. In addition to these, various dihydrazide compounds can be used.

The amount of the crosslinking agent depends on the type of the crosslinking agent and the resin,
Because it depends on the reaction conditions etc., it can not be specified unconditionally
From the viewpoint of the surface strength at the time of swelling and drying, the amount is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, per 100 parts by weight of the water-soluble resin.

Various metal complexes, acids, bases and the like may be added as needed as a crosslinking accelerator.

Additives such as a surfactant, inorganic fine particles and an antistatic agent may be added to the surface layer coating liquid.

Surfactants are added to enhance coating performance, and specific examples thereof include anionic, cationic and
Various surfactants such as nonionic surfactants can be mentioned, and there is no particular limitation. The addition amount is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the water-soluble resin.
Parts by weight are appropriate.

The inorganic fine particles are added in order to improve the writability, and specific examples thereof include silica, titanium oxide, alumina, zinc oxide, calcium carbonate and the like. When adding such inorganic fine particles, 0.1 to 200 parts by weight is added to 100 parts by weight of the water-soluble resin.

The antistatic agent is added in order to improve the paper passing property, and examples thereof include a cationic surfactant. Specific examples of the cationic surfactant include, for example, quaternary ammonium salts. The antistatic agent may be added to the material forming the surface layer, or after forming the surface layer, a material dissolved and dispersed in an appropriate solvent may be applied.

The method for applying the surface layer coating liquid composed of the above-mentioned materials is such that the surface layer can be formed with a uniform film thickness, and the coating amount is 0.5 to 30 g / m ² , preferably 5 to 30 g / m ² after drying. ~ 2
There is no particular limitation as long as it can be controlled to 0 g / m ² , and any known method may be employed. For example, dip coating, spray coating and the like can be exemplified.

After applying the surface layer coating solution, the coating layer (surface layer) is heated to crosslink the water-soluble resin. In the present invention, after applying the surface layer coating solution, prior to crosslinking,
It is preferable to dry once (drying step). Drying may be performed to such an extent that the coating layer does not flow, and is preferably performed in a short time in the present invention.
For several seconds to several minutes. Crosslinking hardly occurs in such a drying step.

In the method of the present invention, the crosslinking of the water-soluble resin is carried out while controlling the rate of evaporation of water from the surface layer to a relatively low level. Specifically, the recording material before crosslinking is 2
Assuming that the amount of water per unit weight when left in a 5 ° C./85% RH environment is W, the residual water amount per unit weight when heated at 70 ° C. for 30 minutes is 0.1 W or more, preferably 0 W Crosslinking by heating is performed in a surface layer state of 2 W or more. In other words, heat crosslinking is performed in the same surface state as the surface state such that the amount of residual moisture per unit weight when heated at 70 ° C. for 30 minutes is within the above range. By selecting a surface state such that the amount of residual moisture per unit weight when heated at 70 ° C. for 30 minutes is within the above range, and performing heat crosslinking in the same surface state as the surface state, heating is performed. The rate of evaporation of water from the surface layer during crosslinking is suppressed, whereby a recording material whose image removal performance does not easily deteriorate even when left for a long time in a high-humidity environment can be easily manufactured without causing yellowing. be able to. When heat crosslinking is performed in a surface state such that the residual water content is less than 0.1 W, the image removal performance during long-term storage is significantly reduced or the obtained recording material is yellowed, and the recording material is yellowed. It has an adverse effect on transparency and whiteness. In the present invention, the residual water content is more preferably 0.8 W or less. 0.
If the power exceeds 8 W, the progress of the effect is slowed down, and the production rate may be deteriorated.

Accordingly, the surface state at the time of heating and crosslinking in the method of the present invention is not particularly limited as long as the surface state is such that the residual moisture content per unit weight when heated at 70 ° C. for 30 minutes is within the above range. . When the surface layer is heated at 70 ° C. for 30 minutes in a state where the surface layer is directly in contact with the surrounding atmosphere, as in the surface state in a general surface heating and crosslinking step,
Since the evaporation of water is relatively fast, the residual water content is 0.1%.
It becomes less than W. For this reason, in the present invention, it is preferable to carry out cross-linking in a surface state that can reduce the water evaporation rate.

The surface state in which the water evaporation rate can be reduced is not particularly limited as long as the rate at which water evaporates from the coating layer (surface layer) can be reduced without inhibiting the crosslinking reaction of the water-soluble resin. Examples include a surface layer state that is not exposed to an atmosphere, and a surface layer state where the surface layer is brought into contact with an ambient atmosphere containing water vapor. In the present invention, it is preferable to adopt a surface state in which the surface layer is not exposed to the surrounding atmosphere from the viewpoint of ease of production.

In the surface state where the surface layer is not exposed to the surrounding atmosphere, the surface of the surface is not in contact with the surrounding atmosphere, that is, the surface of the surface is kept in a closed state, and the evaporation of water from the surface is physically inhibited. By doing so, the water evaporation rate is reduced, and as a result, the above-mentioned residual water content is achieved. Specifically, a surface layer state in which individual recording materials are stacked, or a surface layer state in which a recording material base material in which recording materials before crosslinking are connected in a roll without creating a space may be used. Alternatively, it may be a surface layer state in which a sheet made of a thermosetting resin such as silicone can be adhered to the surface layer, for example, which can ensure adhesion to the surface layer even at the crosslinking temperature. When the surface layer appears as the side surface of the roll in the surface state in which the base material of the recording material is wound in a roll shape, it is preferable that the side surface is brought into close contact with the sheet made of the above-described thermosetting resin.

In the surface state in which the surface layer is brought into contact with the surrounding atmosphere containing water vapor, the presence of water vapor in the surrounding atmosphere suppresses the evaporation of water from the surface of the surface layer, thereby reducing the water evaporation rate. Achieve the above residual water content. In the present invention, crosslinking is preferably performed while the surface layer is brought into contact with an ambient atmosphere saturated with water vapor. Here, the term “saturation” means the saturation of water vapor at the adopted crosslinking temperature.

In the case where the surface layer is formed on one surface of the base material layer or the surface layer is formed on both surfaces of the base material layer, the recording material before crosslinking is similarly heated at 25 ° C./85%
Regarding the water content per unit weight W when left in an RH environment, the heat crosslinking may be performed in a surface state such that the residual water content per unit weight when heated at 70 ° C. for 30 minutes is within the above range. .

In the present specification, the recording material before crosslinking is 25 ° C. /
The moisture content per unit weight W (g / g) when left in an environment of 85% RH is determined by applying the coating solution for the surface layer, and then drying the unrecorded recording material before contacting the surrounding layer with the surrounding atmosphere. From the weight of the recording material (W1) (g) after being left for 4 hours in the above environment, the recording material was vacuum dried at 50 ° C. for 3 hours with the surface layer in contact with the surrounding atmosphere. The value obtained by dividing the value obtained by subtracting the weight (W2) (g) of the recording material after coating by W2 is used. Even if a recording material is used, the obtained W hardly changes. Here, “drying” has the same meaning as “drying” in the drying step. Even if the recording material is left in an environment of 25 ° C./85% RH for more than 4 hours, W1 hardly changes, and even if it is vacuum-dried at 50 ° C. for more than 3 hours, W2 hardly changes. do not do. The ambient atmosphere when measuring W1 is air.

The “residual moisture content per unit weight when heated at 70 ° C. for 30 minutes” means that the recording material before crosslinking is heated at 70 ° C. for 30 minutes in the selected surface state. It can be obtained by measuring the recording material weight (W3) (g) and dividing the value obtained by subtracting the W2 (g) from W3 by W2. As the recording material to be measured, after the application of the surface layer coating liquid, the dried recording material before cross-linking may be used, or after the application of the coating liquid, the recording before cross-linking without drying. Even when the material is used, the obtained value hardly changes. Here, “drying” has the same meaning as “drying” in the drying step.

In the heat crosslinking step of the present invention, the crosslinking reaction conditions such as crosslinking temperature and reaction time are not particularly limited as long as the water-soluble resin can be sufficiently crosslinked in the above surface state. Usually 20 to 250 ° C, preferably 80 to 1
0.5 to 500 hours at 50 ° C., preferably 10 to 200 hours
Heated for hours.

In the present invention, by performing heat crosslinking as described above, a recording material having a surface layer having an appropriate water swelling property and having a reduced image removal performance even after being left for a long period of time can be yellowed. Can be obtained without generating any.
Here, the term "water-swellable" means a property that swells in water or an aqueous solvent but does not dissolve.

In the present invention, a monomer or oligomer having a double bond and a polymerization initiator thereof are further added to the coating solution for the surface layer, and if necessary, ultraviolet light or an electron beam or the like is applied while performing the crosslinking. Irradiation may generate a water-insoluble component in the water-soluble resin to impart water swelling to the water-soluble resin. As described above, by adding the above-mentioned monomer or oligomer in advance and generating the water-insoluble component, the water-soluble resin can be easily imparted with water swelling, and as a result, the control of the amount of residual moisture becomes easy. Examples of the monomer or oligomer having a double bond include diacrylate, dimethacrylate, and urethane acrylate monomers and oligomers.

FIG. 1 is a schematic cross-sectional view of an example of a recording material that can be manufactured by the above method. 1 is a base material layer and 3 is a surface layer. FIG. 1 shows a configuration in which the printing material 4 is printed on the surface of the surface layer 3. Although FIG. 1 shows a configuration in which the surface layer 3 is formed on one surface of the base material layer 1, the surface layer 3 may be formed on both surfaces.

In the present invention, from the viewpoint of improving the adhesion between the surface layer and the substrate layer, prior to the formation of the surface layer on the substrate layer,
It is preferable to form an intermediate adhesive layer on the surface of the base material layer on which the surface layer is formed.

The intermediate adhesive layer is made of a resin having high adhesiveness to the base material layer, and optionally contains a compound having a functional group capable of chemically bonding to the surface layer constituent resin (reactive compound). When a relatively poorly water-resistant material such as pulp paper is used for the base material layer, it is more preferable that the base material layer also has a water resistance function so that the aqueous solvent does not penetrate into the base material layer.

Examples of the resin having high adhesiveness and high water resistance include a urethane resin, an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, a vinyl acetate resin, a vinyl chloride resin and the like, and preferably a polymethyl methacrylate resin. , Polyester resins, polycarbonate resins, vinyl chloride resins, urethane resins and the like.

The reactive compound optionally contained in the intermediate adhesive layer is not particularly limited as long as it has a functional group capable of chemically bonding to the resin constituting the surface layer. For example, a methylol compound, an isocyanate compound, an aldehyde compound, Epoxy compounds, aziridine compounds and the like can be used. When the resin constituting the surface layer is a resin having a hydroxyl group such as polyvinyl alcohol and methyl cellulose, an isocyanate compound, a methylol compound, an aldehyde compound, and an epoxy compound are preferable. When the resin constituting the surface layer is a resin having a carboxyl group such as polyacrylic acid, an isocyanate compound, an epoxy compound, and an aziridine compound are preferable. Specific examples of these compounds include the same compounds as the compounds exemplified as the crosslinking agent described above.

The reactive compound is preferably a solid or wax at room temperature or a viscous liquid at room temperature.
When the reactive compound is a solid or waxy liquid at room temperature or a viscous liquid at room temperature, it does not evaporate due to drying at the time of application formation of the intermediate adhesive layer, and since the surface is not sticky at the time of drying, the surface layer is not sticky. There is an advantage that application becomes easy. In addition, when a reactive compound that dissolves in water or has affinity for water is used, there is no need to use an organic solvent to apply and form the intermediate adhesive layer, and the organic solvent is contained in the intermediate adhesive layer. It can be prevented from remaining.

To coat the intermediate adhesive layer on the base material layer, the resin and, if desired, the above-mentioned reactive compound are dissolved in a suitable solvent, for example, tetrahydrofuran (THF), dioxane, acetone, ethyl acetate, methyl ethyl ketone (MEK) or the like. The solution can be applied by a solvent application method or a melt application method of applying and drying the resulting solution. What dissolved or disperse | dissolved resin, such as water-soluble or hydrophilic polyurethane and polyester in water, can also be used. Such resin solutions and resin emulsions are commercially available, and using them has the advantage that a coating film can be formed without using an organic solvent, especially a non-aqueous organic solvent. If the intermediate adhesive layer and the surface layer are formed using an aqueous solvent, the recording material can be manufactured without using a non-aqueous organic solvent, and the safety is improved, and the non-aqueous organic solvent in the recording material is improved. The problem of the residual solvent can be prevented. That is, safety during manufacturing can be improved, and problems such as generation of residual solvent gas from the inside due to heating of the recording material by paper passing through a copying machine or the like can be suppressed. When an aqueous solvent is used, the addition of a surfactant makes it easier to apply the intermediate adhesive layer. The coating amount is 0.5 to 20 g / m ² by the solvent coating method or the melt coating method.
Extent, preferably 0.5~12g / m ^2, more preferably about forming the intermediate bonding layer such that about 0.5~6g / m ^2. If the coating amount is less than 0.5 g / m ² , coating unevenness is likely to occur, and an uncoated portion tends to be formed. 20 g / m ²
If the number exceeds the range, problems may occur in the strength, heat resistance, water resistance and the like of the recording material.

If the reactive compound is a high molecular weight substance which has a film-forming property and excellent adhesiveness to the substrate layer, it is formed by dissolving itself in a solvent or the like, coating and drying. It is also possible. In the case of coating by adding to the resin solution, the amount of the reactive compound to be added may be 100
The amount can be, for example, 5 to 50 parts by weight with respect to parts by weight.

In order to improve the adhesiveness between the intermediate adhesive layer and the surface layer, the intermediate adhesive layer may be subjected to a corona discharge treatment.

When a paper or fibrous base material is used, the base material is immersed in the coating solution for forming the intermediate adhesive layer, the base material is impregnated with the coating solution, and the intermediate bonding between the fibers constituting the base material is performed. The layer material may be filled.

In the present invention, when forming an intermediate adhesive layer, a surface layer is formed on the intermediate adhesive layer. The constituent material of the surface layer and the forming method are the same as described above.

FIG. 2 is a schematic sectional view of an example of a recording material having an intermediate adhesive layer which can be produced by the method of the present invention. 1 is a substrate layer, 2 is an intermediate adhesive layer, and 3 is a surface layer. FIG. 2 shows a configuration in which the printing material 4 is printed on the surface of the surface layer 3. Although FIG. 2 shows a configuration in which the intermediate adhesive layer 2 and the surface layer 3 are formed on one surface of the base material layer 1, the intermediate adhesive layer 2 and the surface layer 3 may be formed on both surfaces.

The recording material obtained by the method of the present invention as described above can be suitably used for a method of removing a printing material which undergoes a swelling of the surface layer → physical rubbing by brushing or the like → drying process. It has excellent image removal performance even when stored (left) for a long period of time, particularly in a high humidity environment, and does not cause problems such as occurrence of yellowing. Furthermore, it is excellent in deinking properties at initial and repeated use.

Hereinafter, a method for removing a printing material from a recording material having a printing material such as toner printed on the surface thereof will be described. The method comprises a step of supplying a recording material on which a printing material is printed to a solvent capable of swelling the surface layer, and scraping the printing material from the swollen recording material surface with a physical force. Hereinafter, a more detailed description will be given with reference to the drawings.

FIG. 3 is a process flow chart for explaining an example of a printing material removing method. In FIG. 3, the recording material 1
No. 00 has an intermediate adhesive layer and a surface layer formed on both surfaces thereof. A printing material 4 such as toner is printed on the surface of the recording material. As a printing material, a toner used for electrophotography is preferably used. In addition, a recording material used for an ink-jet method, a thermal transfer method, a printing method, and the like using a hot melt ink, and other oil-based paint agents For example, a type that forms a film-like image by adhering to the surface of a recording material such as a recording medium can be used. The recording material is conveyed from right to left in the drawing.

First, a surface layer swelling solvent is supplied from the solvent supply device 11 to the surface layer of the recording material on which the printing material 4 is printed. As the solvent capable of swelling the surface layer, various solvents such as an aqueous solvent, that is, water, a mixed solvent of water and an aqueous organic solvent, or an aqueous organic solvent can be used. Also,
Desired additives such as a surfactant and inorganic fine particles may be added. As described above, the present embodiment has a great advantage in that the printing material can be removed using water. In the following description, the case where water is used will be described.

As shown in FIG. 3, the water may be supplied by showering water from the shower device 11 onto the surface layer, or may be immersed in water (not shown).
It takes about 15 seconds to 150 minutes for water to permeate the surface of the recording material.
It is preferable to make contact with water for about a second. The longer the contact time, the more water can permeate, but the more time it takes to process. When water penetrates into the surface of the recording material, the surface swells (the swollen surface is shown as 13), and the adhesive force between the printing material 4 and the surface decreases. At this time, the water temperature is 1
About 5 ° C to 45 ° C is appropriate. If the temperature is too high, the evaporation of water increases, and if the temperature is too low, a sufficient cleaning effect may not be obtained.

After the water has sufficiently penetrated into the surface layer of the recording material, the recording material is further transported to the printing material removal area, and the brush 1
Called 4 The brush 14 is rotating, and the printing material 4 on the recording material 100 is removed by the brush. In the present invention, in addition to the brush, a means of applying a physical or mechanical force to the surface to rub or scrape the surface, such as a blade or a cloth, may be employed.
In FIG. 3, the brush 14 is arranged outside the liquid,
It may be arranged in the liquid. The length of the bristle of the brush 14 is 5
The thickness can be about 20 mm, and the thickness can be about 10-60 μm. The material is not particularly limited, but nylon or the like is suitable.

The paper passing speed, that is, the recording material is the brush 14
May be determined in consideration of the balance between the processing time and the cleaning performance, for example, from 0.5 cm / sec.
It can be 5 cm / sec. The rotation speed of the brush is preferably 5 times or more, more preferably 10 times or more the transport speed.

After the printing material 4 is removed, the recording material is conveyed to a shower area, where a cleaning shower 15 is applied to the surface of the recording material, and the printing material remaining on the surface of the recording material is washed away. As the liquid used for the shower 15, the same aqueous solvent as used for swelling the surface layer can be used. The same solvent used to swell the surface layer may be used. It is particularly preferred to use water.

After the shower 15 is applied, the recording material is further conveyed to a drying area and is dried by the dryer 16.
The drying method may be a contact type such as a heat roller, or a non-contact type such as a far-infrared lamp. The heating temperature is suitably about 70 to 150 ° C.

FIG. 4 is a diagram showing an embodiment of a cleaning device to which the above-described cleaning method can be applied.
The apparatus shown in FIG. 4 includes a cleaning tank 22 for storing a liquid 30 for expanding a recording material in a casing 23. The cleaning tank 22 is connected to a pump 20 having a filter for removing printing material in the liquid in the tank, and the pump 20 is further provided with a swelling shower 11 and a rinsing shower 15 via a pipe 31. It is connected.

The liquid in the cleaning tank 22 is supplied to the pump 20.
After being purified by the internal filter, it is sent to showers 11 and 15 through a pipe 31, and is used as a liquid for swelling the recording material in the shower 11 and as a rinsing liquid in the shower 15.

The recording material is introduced into the apparatus by a paper feed roller 21, and is sprayed with a swelling liquid by a shower 11, passes through a guide 26 and a transport roller 24, and is immersed in a liquid 30 in a cleaning tank 22. You. And
After standing still for a predetermined time, the conveying roller 24 and the guide 28
Is sent to the opposite portion of the brush 14 to remove the printing material.

Thereafter, the recording material passes through the guide 29, the transport roller 25, and the guide 27, is sprayed with a rinsing liquid by the shower 15, is finally dried by the drying roller 17, and is discharged out of the apparatus.

FIG. 5 is a view showing another embodiment of the cleaning device. In the apparatus shown in FIG.
The recording material introduced by 1 is transported by the transport rollers 32, 3
By being transported directly to the cleaning tank 22 and immersed in the liquid 30 by the guide 3 and the guide 26, water permeates the surface layer of the recording material before brushing. After passing through the opposite portion of the brush 14, the liquid 3
After passing through 0, a rinsing effect is obtained by reaching the drying roller 17. FIG.
The same components as those described above are denoted by the same reference numerals, and detailed description is omitted.

[0070]

EXAMPLES Production of Recording Material A Base layer: A high quality paper weighing 80 g / m ² was used as the base layer. Intermediate adhesive layer; water-dispersible urethane resin solution (HUX-26
0; 100 g of Asahi Denka Kogyo Co., Ltd.) and 5 g of melamine-formaldehyde resin (Sumileze 613; Sumitomo Chemical Co., Ltd.)
And polyoxyethylene nonyl ether (Nonipol 6
0; Sanyo Chemical Co., Ltd.) was added, and after stirring, the mixture was applied to both sides of the substrate layer with a bar coater and dried at 120 ° C. for 30 seconds. At this time, the coating amount was 12 g / side per side.
m ² . Surface layer: 20 g of anion-modified polyvinyl alcohol (KM-618; manufactured by Kuraray Co., Ltd.) as water-soluble resin and 180 g of water
To prepare a resin solution. 4 g of an epoxy crosslinking agent (EX-313; manufactured by Nagase Kasei Co., Ltd.) and 0.4 g of polyoxyethylene nonyl ether as a surfactant were added to the resin solution.
And 4 g of silica fine particles (Sylysia 450; manufactured by Fuji Silysia) were added, followed by stirring for 10 minutes. This was applied on the intermediate adhesive layer and dried at 120 ° C. for 45 seconds. The coating amount at this time was 11 g / m ² per one side. This was designated as recording material A. The recording material A was a roll having a width of 30 cm and a length of 150 m. Cut this part out,
Weight after storage for 4 hours in a 25 ° C./85% environment (W
1) was measured, and then the weight (W2) after vacuum-drying this at 50 ° C. for 3 hours was measured. From these measurements W
Was 1.25 g / g (W _A ).

Production of Recording Material B Base Layer: PET having a thickness of 100 μm was used as the base layer. Intermediate adhesive layer; water-dispersible urethane resin solution (HUX-26
0; 100 g of Asahi Denka Kogyo Co., Ltd.) and 5 g of melamine-formaldehyde resin (Sumileze 613; Sumitomo Chemical Co., Ltd.)
And polyoxyethylene nonyl ether (Nonipol 6
0.1 g (manufactured by Sanyo Chemical Co., Ltd.) was added, and after stirring, the mixture was applied to both sides of the base material layer with a bar coater and dried at 120 ° C. for 15 seconds. The amount of coating at this time was 5 g / m per side.
^{Was 2} . Surface layer: 16 g of anion-modified polyvinyl alcohol (KL-318; manufactured by Kuraray) as water-soluble resin and 184 g of water
To prepare a resin solution. 2 g of an epoxy crosslinking agent (EX-313; manufactured by Nagase Kasei Co., Ltd.) and 0.4 g of polyoxyethylene octyl ether as a surfactant were added to the resin solution.
g and silica fine particles (Silicia 450; manufactured by Fuji Silysia Ltd.) were added, and the mixture was stirred for 10 minutes. This was applied on the intermediate adhesive layer and dried at 150 ° C. for 2 minutes.
The coating amount at this time was 8 g / m ² per one side. This was designated as recording material B. Recording material B was heated at 25 ° C / 85%
The weight (W1) after storage for 4 hours in the environment was measured, and then the weight (W1) after vacuum drying at 50 ° C. for 3 hours (W1).
2) was measured. From these measured values, W is 1.48 g /
g (W _B ).

Example 1 The recording material A was cut into A4 size paper, and the surface layer was sealed in a silicone sheet and heated at 120 ° C. for 2 hours to thermally crosslink the water-soluble resin in the surface layer. When the recording material A was heated at 70 ° C. for 30 minutes in the same state as described above (a state sandwiched between silicone sheets), the residual water content was 0.25 g / g (0.2 W _A ). . Example 2 The recording material A was placed in a heating furnace in a roll form,
By heating for 4 hours, the water-soluble resin in the surface layer was thermally crosslinked. Further, when the recording material A was heated at 70 ° C. for 30 minutes in the same state (roll-like state) as described above, the residual moisture amount was 0.74 g / g (0.592 W _A ).

Example 3 The recording material B was heated at 120 ° C. for 4 hours under a saturated vapor pressure to thermally crosslink the water-soluble resin in the surface layer. Further, the recording material B was heated to 70 ° C. in the same state as described above (under a saturated vapor pressure).
The residual water content after heating for 30 minutes at
Was 5g / g (0.372W _B).

Comparative Example 1 The recording material A was heated in an ordinary atmosphere at 140 ° C. for 15 minutes to thermally crosslink the surface water-soluble resin. Also,
The remaining water content when the recording material A was heated at 70 ° C. for 30 minutes in the same state as described above was measured to be 0.06 g / g (0.
048 W _A ). Here, "heating under a normal atmosphere" means that the recording medium is heated in a heating furnace having an air atmosphere inside.
It means that the surface layer is put in direct contact with the air atmosphere and heated.

Comparative Example 2 The recording material B was heated under a normal atmosphere at 120 ° C. for 2 hours to thermally crosslink the water-soluble resin in the surface layer. The residual moisture content when the recording material B was heated at 70 ° C. for 30 minutes in the same manner as described above was 0 g / g (0 W _B ). Here, “heating in a normal atmosphere” refers to Comparative Example 1.
Has the same meaning as in.

Evaluation (Deinking properties (initial, repeated and after standing)) A commercially available laser beam printer (LP-170) was used for each recording material.
0; manufactured by Epson Corporation).
The toner was removed by an apparatus having the configuration shown in FIG. The immersion time at this time was 3 minutes. After repeating the process of copying and removing the image five times, the toner removal property was evaluated.

Next, a copying machine (EP-405) is applied to each recording material.
0; manufactured by Minolta Co., Ltd.).
%, The toner was removed with an apparatus having the configuration shown in FIG.

The ranks in the evaluation were as follows. "A" indicates that 95% or more of the toner was removed, "B" indicates that 80 to 95% of the toner was removed, and "C" indicates that less than 80% of the toner was removed.

The operating conditions of the apparatus having the configuration shown in FIG. 4 were as follows.・ Hair length 10mm, thickness 3
Use a brush roller with a core diameter of 12 mm having a brush brush made of nylon of 0 μm. ・ Water temperature in the tank: 30 ° C. ・ Paper passing speed: 1 cm / sec ・ Brush rotation speed / paper passing speed = 30 ・ Heat roller temperature: 110 ° C.

(Coloring) The coloring of each recording material was visually evaluated. Those that were not colored were marked with “○”, and those that were colored were marked with “x”.

Table 1 shows the obtained results.

[0082]

[Table 1]

[0083]

According to the method of the present invention, it is possible to obtain a recyclable recording material whose image removing performance is hardly deteriorated even when left in a high humidity environment for a long time, without causing yellowing. . The recording material obtained by the method of the present invention is also excellent in deinking properties at initial and repeated use.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a recording material obtained by a method of the present invention.

FIG. 2 is a schematic sectional view of an example of a recording material obtained by the method of the present invention.

FIG. 3 is a process flow chart for explaining a method of removing a printing material.

FIG. 4 is a schematic configuration diagram illustrating an example of a cleaning device.

FIG. 5 is a schematic configuration diagram illustrating an example of a cleaning device.

[Explanation of symbols]

1: base material layer, 2: intermediate adhesive layer, 3: surface layer, 4: printing material, 11: shower device, 12: intermediate adhesive layer + surface layer, 1
3: swollen surface layer, 14: brush, 15: cleaning shower, 16: dryer, 100: recording material.

Claims (2)

[Claims] 1. A method for producing a recyclable recording material in which a coating liquid for a surface layer containing at least a water-soluble resin is applied onto a base layer or an intermediate adhesive layer and heated to crosslink the water-soluble resin. The recording material before crosslinking is 25 ° C /
Assuming that the moisture content per unit weight when left in an environment of 85% RH is W, the surface layer state is such that the residual moisture content per unit weight when heated at 70 ° C. for 30 minutes is 0.1 W or more. A method for producing a recording material, comprising performing thermal crosslinking. 2. A method for producing a recyclable recording material in which a coating liquid for a surface layer containing at least a water-soluble resin is applied onto a base material layer or an intermediate adhesive layer and heated to crosslink the water-soluble resin. And subjecting the surface layer to heat crosslinking in a surface layer state without exposing the surface layer to an ambient atmosphere.