JP4655970B2 - Pressure-sensitive adhesive sheet for electrophotographic printing and method for producing the same - Google Patents

Description

  The present invention relates to a method for producing a pressure-sensitive adhesive sheet for electrophotographic printing used in various systems such as postcards and cards having confidentiality, and a toner stain having excellent printability and printability produced by the production method. The present invention relates to a pressure-sensitive adhesive sheet for electrophotographic printing having a releasable adhesive surface that does not generate odor.

  2. Description of the Related Art In recent years, a postcard system having a confidential property by folding a sheet on which necessary information is recorded in two or three in accordance with the revision of the Postal Law has been put into practical use and has been widely used. Such a friendly postcard usually has no adhesiveness on one side of the base sheet, and exhibits adhesiveness by applying pressure in a state where the adhesive layers face each other. A confidential postcard (pressure-sensitive adhesive sheet) having an adhesive layer that can be used is used.

  Usually, the manufacturing process of a confidential postcard includes firstly a confidential postcard manufacturing process in which an adhesive layer is formed on a base sheet and cut into a predetermined size, and secondly, on the adhesive layer surface of the confidential postcard base paper. A printing process for printing standard items and invariant information as a postcard, third, a printing process for printing secret variable information such as personal information and destination, fourth, V-folding (two-folding) or Z-folding (three-folding) ) And the pressure variable lamination process so that the secret variable information is not visible from the outside, and becomes a confidential postcard through those processes. Private postcards can be used at the same postage as regular postcards.

The second printing step in the above series of confidential postcard manufacturing steps is usually a step of printing with a form printer. As a method of printing with a form printer, the ink is transferred to one side of the confidential post paper by passing between the blanket cylinder and the impression cylinder (metal roll) on which the confidential post paper is transferred, and then A method of winding in a roll shape through an ink curing / fixing step with heat or ultraviolet rays, or folding in a Z-fold shape is known.
At this time, there is a problem that blocking occurs at the perforation when folded in the Z-fold shape, and troubles such as inability to feed paper occur during the printing process or the crimping process.

In order to prevent this blocking, a method of adding a pigment having an average particle diameter exceeding 20 μm to the adhesive layer has been proposed (Patent Document 1).
However, in this method, an anti-blocking effect is recognized, but the large particle size is caused by rubbing the confidential postcard paper on a turn bar (paper reversing device that reverses the front and back of the base paper) used for double-sided printing with a form printer. Dirt such as an adhesive layer containing paper pigment or paper dust adheres to the turn bar (hereinafter referred to as “turn bar dirt”), and the dirt also adheres to the confidential postcard paper, degrading printability, This may cause printing and printing defects in the printing process.

  In order to improve both blocking resistance and printability, a method has been proposed in which a thermoplastic resin having an average particle size of 10 μm or less is added to the adhesive layer (Patent Document 2). Although this method is effective for blocking resistance and printability, among thermoplastic resins, animal and vegetable waxes such as carnauba wax, petroleum waxes such as paraffin wax, and synthetic waxes such as polyethylene wax are used. In the confidential postcard paper manufacturing process, when the coated surface comes into contact with the metal roll after coating / drying of the adhesive layer or during cutting, the wax adheres during the long-time coating / cutting operation. There was a problem of accumulation.

  Similarly, in the printing process, when the confidential postcard paper passes between the blanket cylinder and the impression cylinder, there is a problem that the wax adheres to and accumulates on the impression cylinder. Further, in the crimping process, wax sometimes adheres and accumulates on the impression cylinder (metal roll) of the dry sealer during the crimping. In any case, if the dirt becomes severe, it is necessary to remove the dirt regularly, which causes a problem in workability, and problems such as printing / printing unevenness are likely to occur.

Moreover, in the method described in the Example of the said patent document 1, since many silica is contained in a coating layer, although an effect is acquired at the time of the printing of an inkjet system, on the other hand, the surface strength of a coating layer is inferior. For this reason, when printing is performed by an electrophotographic printing method typified by a laser printer, there is a defect that a coating layer adheres to the toner fixing roll and toner fixing stains occur.
JP-A-8-92534 Japanese Patent Laid-Open No. 2005-139397

  The object of the present invention is to have an excellent release effect on the turn bar, and stains on the metal roll in the confidential postcard manufacturing process, the impression cylinder of the form printing machine in the printing process, the impression cylinder of the dry sealer in the crimping process, etc. To provide a pressure-sensitive adhesive sheet for electrophotographic printing that does not cause adhesion, and a pressure-sensitive adhesive sheet for electrophotographic printing that does not cause printing / printing unevenness and toner fixing stains obtained by the manufacturing method. is there.

The present inventors have in the manufacturing process of the electrophotographic printing pressure-sensitive adhesive sheet, by blending fatty particles child and starch particles in the adhesive composition for peelable adhesive surface having a releasable adhesive layer The inventors have found that the above problems can be overcome. The present invention includes the following inventions.

(1) By an adhesive composition containing an adhesive and fatty acid particles , particularly stearic acid particles and starch particles, usually without adhesiveness, and by pressure treatment with the adhesive layers facing each other A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing, comprising: forming a releasable adhesive layer that can be bonded and the adhesive layers after bonding are peelable from each other on at least one surface of the substrate sheet.

(2) At least the other surface of the substrate sheet surface on which the removable adhesive layer is formed is usually not adhesive and can be bonded by pressure treatment with the adhesive layers facing each other; and The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to (1), comprising forming an adhesive layer for permanent adhesion having no removability.

(3) the fatty particles child of 8 or more saturated fatty acids of carbon number 8 or more unsaturated fatty acid carbon is a particle having 8 or more oxy fatty acid carbon, in particular stearic acid particles (1) or (2) A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing as described in 1.

(4) Average particle diameter 0.1~20μm of the fatty particles child, preferably 2～18Myuemu, or less more preferably greater than 10 [mu] m 15 [mu] m, the amount of the adhesive composition is 0.1 to 5 Electrograph according to any one of (1) to (3), characterized in that it is in mass%, preferably 0.2 to 3 mass%, more preferably 0.3 to 1 mass%. A method for producing a pressure-sensitive adhesive sheet for printing.

(5) The starch particles are particles having an average particle diameter of 5 to 30 μm, preferably 10 to 20 μm selected from wheat starch, potato starch, tapioca starch, and the like, and an adhesive composition for the releasable adhesive layer Any one of (1) to (4), wherein the blending amount is 10% by mass to 60% by mass, preferably 20% by mass to 50% by mass, and more preferably 30% by mass or more and less than 40% by mass. 2. A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to item 1.

(6) In the adhesive composition for the releasable adhesive layer, as a binder, polyvinyl alcohol (PVA), modified PVA, hydroxyethyl cellulose, CMC, cellulose derivative, starch derivative, etc., aqueous emulsion type polymer latex, SBR (1) to (1) which is formed by blending at least one selected from latex, NBR latex, MBR latex, polyvinyl acetate, acrylic resin, styrene-acrylic copolymer, ethylene-vinyl acetate polymer, polyvinyl butyral, polyurethane and the like. 5. A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to any one of 5).

(7) The adhesive composition for the releasable adhesive layer, wherein inorganic pigment or organic pigment particles are blended as an adhesion control agent, according to any one of (1) to (6). A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing.

(8) The base sheet is one selected from paper such as fine paper, medium paper, art paper, coated paper, synthetic paper, synthetic resin film, metal foil, and non-woven fabric (1) to (7 The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to any one of the above.

(9) By being subjected to pressure treatment in a state in which the adhesive layer is produced by the production method according to any one of (1) to (8) and usually has no adhesiveness and the adhesive layers face each other. A pressure-sensitive adhesive sheet for electrophotographic printing, which has a re-peelable adhesive layer that can be bonded and can be peeled off after bonding.

Method for producing an electrophotographic printing pressure-sensitive adhesive sheet of the present invention, by blending particles of fat acids in refastenable adhesive layer, confidential postcard base paper manufacturing process when a metal roll, form printing at the time of printing process This is an excellent method in which no dirt adheres to the impression cylinder of the machine and the impression cylinder of the dry sealer during the crimping process.
The pressure-sensitive adhesive sheet for electrophotographic printing produced by the above method is a pressure-sensitive adhesive sheet for electrophotographic printing that has excellent printability and printability and does not cause toner fixing stains.

  The pressure-sensitive adhesive sheet for electrophotographic printing of the present invention is usually non-adhesive on at least one surface of the base sheet, and can be bonded by pressure treatment with the adhesive layers facing each other, and A releasable adhesive surface having a releasable adhesive layer from which the adhesive layers after bonding can be peeled is formed.

  As an example in which a removable adhesive surface having a removable adhesive layer is formed on at least one surface of the substrate sheet, the removable adhesive layer is formed only on one surface of the substrate. One having a removable adhesive layer formed on both sides, a removable adhesive layer formed on one side and a non-removable adhesive layer on the other side (hereinafter referred to as “permanent adhesion”). What is also referred to as “agent layer” is included. Both the releasable adhesive layer and the permanent adhesive layer do not exhibit adhesiveness under normal conditions, and are bonded by pressing with a dry sealer or the like. Such a releasable adhesive layer and permanent adhesive layer of an electrophotographic printing pressure-sensitive adhesive sheet are prepared by using an adhesive, an adhesive force control agent, a binder, and the like in combination with the adhesive composition forming the adhesive layer. It can form by adjusting the adhesive force of each adhesive bond layer.

As fatty acid particles to be blended in the adhesive composition for forming the releasable adhesive layer in the pressure-sensitive adhesive sheet for electrophotographic printing of the present invention, saturated or unsaturated fatty acids having 8 or more carbon atoms (caprylic acid, capric acid, Saturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid, unsaturated fatty acids such as octenoic acid, tetradecenoic acid, hexadecenoic acid, oleic acid, linoleic acid, and linolenic acid), oxy fatty acids ( Particles such as 12-hydroxystearic acid and fatty acid having a hydroxyl group such as ricinoleic acid), and mixtures of two or more thereof. Among these, particles of saturated or unsaturated fatty acids having 12 to 20 carbon atoms and oxy fatty acids are preferable, and more preferable particles include particles of palmitic acid, stearic acid, oleic acid, and linoleic acid , most preferably stearin. Examples include acid particles .

Further, it is possible to incorporate particles of fatty acid metal salt to the adhesive composition to form a refastenable adhesive layer in the electrophotographic printing pressure-sensitive adhesive sheet of the present invention. Examples of the particles of the fatty acid metal salt include particles of the fatty acid and magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, or a mixed salt of these metals. Among these, a salt particle of a saturated or unsaturated fatty acid having 12 to 20 carbon atoms or an oxy fatty acid and magnesium, calcium, zinc, barium or the like, or a mixture of particles of these salts, more preferably, Examples thereof include particles of palmitic acid, stearic acid, oleic acid, linoleic acid and calcium, zinc or the like, or a mixture of particles of these salts. Before particles Kiabura fatty acid salts may be used alone, it can be used by mixing them arbitrarily.

The average particle diameter of the particles of the fatty acid used in the present invention is usually 0.1 to 20 [mu] m, preferably not 2～18Myuemu, more preferably greater than 10 [mu] m 15 [mu] m or less. When the average particle diameter exceeds 20 μm, the particles easily fall off and turn bar contamination occurs, which causes a problem in paper passing of a printing machine or printer. If the average particle size is less than 0.1 μm, the effect of improving the turn bar contamination is not sufficient. In addition, in this invention, an average particle diameter means the 50% volume average particle diameter measured using laser diffraction type particle size distribution measuring device SALD-2000J [made by Shimadzu Corp.] based on JISZ8825-1.

The amount of fatty acid particles child to re-peelable adhesive layer is generally 0.1 to 5% by weight, preferably from 0.2 to 3 wt%, more preferably less than 1 wt% 0.3 wt% It is. If it is less than 0.1% by mass, the effect of improving the turn bar dirt is not sufficient, and even if it is added more than 5% by mass, the effect of the present invention does not change.

The peelable adhesive layer, in addition to the fatty particles child, starch particles are blended. Examples of starch particles include wheat starch, potato starch, tapioca starch and the like. The starch particles are used as a spacer for the purpose of preventing blocking and preventing toner fixing stains when using a color laser printer, and those having an average particle diameter of 5 to 30 μm, preferably 10 to 20 μm can be used.

  The compounding amount of the starch particles to the adhesive layer having removability is usually 10% by mass to 60% by mass, preferably 20% by mass to 50% by mass, more preferably 30% by mass or more and less than 40% by mass. is there. If the amount is less than 10% by mass, the effect of improving the turn bar stain is not sufficient, and even if the amount exceeds 60% by mass, the effect of the present invention does not change.

  Inorganic and organic pigments can be used for the releasable adhesive layer. For example, zinc oxide, titanium oxide, zeolite, talc, clay, calcium carbonate, calcium silicate, magnesium silicate, aluminum hydroxide, silica, alumina, colloidal silica, plastic pigment, polyethylene resin, polypropylene resin, fluorine resin, etc. are used. . In particular, silica is preferable because it has excellent ink acceptability and improves printability. The blending amount of the inorganic and organic pigments in the adhesive layer having removability is usually 3% by mass to 40% by mass, preferably 5% by mass to 30% by mass, and more preferably 10% by mass or more and 20% by mass. Is less than.

Examples of the adhesive used in the removable adhesive layer of the present invention include ethylene-vinyl acetate resin, (meth) acrylic acid ester copolymer resin, vinyl chloride resin, vinylidene chloride resin, and synthetic rubber. Resin, natural rubber resin, acrylic modified natural rubber resin, and the like, and these can be used alone or in combination.
In particular, when using a natural rubber-based resin, if an unsaturated double bond is present, the heat resistance is inferior. Therefore, it is recommended to use one saturated with a double bond by a method such as hydrogenation. And more preferable in terms of heating odor.
The compounding amount of the adhesive in the adhesive layer having removability is usually 20% by mass to 60% by mass, preferably 25% by mass to 50% by mass, and more preferably 30% by mass or more and less than 40% by mass. .

  In the removable adhesive layer, it is preferable to incorporate a binder in order to bring the adhesive or adhesive force control agent into close contact with the base sheet. As binders, polyvinyl alcohol (PVA), modified PVA, hydroxyethyl cellulose, CMC, cellulose derivatives, starch derivatives, etc., aqueous emulsion type polymer latex, SBR latex, NBR latex, MBR latex, polyvinyl acetate, acrylic resin, styrene- Examples include acrylic copolymers, ethylene-vinyl acetate polymers, polyvinyl butyral, polyurethane, and the like, and these binders can also be used in combination. The blending amount of the binder in the adhesive layer having removability is usually 3% by mass to 20% by mass, preferably 5% by mass to 15% by mass, and more preferably 7% by mass or more and less than 12% by mass.

  In addition, the re-peelable adhesive layer has additives such as pigment dispersants, thickeners, fluidity improvers, antifoaming agents, foam inhibitors, mold release agents, foaming agents, penetrants, colored dyes, ultraviolet rays Absorbers, antistatic agents, surfactants, antioxidants, preservatives, water resistance agents, and the like can be blended in appropriate amounts.

  As the base sheet, paper such as fine paper, medium paper, art paper, coated paper, synthetic paper, synthetic resin film, metal foil, non-woven fabric, etc. can be used, and these are laminated or surface-treated. You may use what was.

The method for applying the adhesive layer to the surface of the base sheet is not particularly limited, but various blade coaters, roll coaters, air knife coaters, bar coaters, gravure coaters, curtain coaters, etc. are used. In the present invention, an air knife coater, a bar coater, a gravure coater or the like is preferable. The coating amount is in the range of ^{2 to} 30 g / m ² , preferably 3 to 15 g / m ² .

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the examples, “parts” and “%” are parts by mass and mass% unless otherwise specified.

Example 1
[Production of fatty acid dispersion]
350 g of stearic acid powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a stearic acid dispersion having a solid content of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 20 to 30 ° C. in a disk type bead mill using glass beads having a diameter of 5 mm. The average particle diameter of the particles in the obtained stearic acid dispersion was 10.3 μm. This dispersion is referred to as Dispersion A.

(Formation of releasable adhesive layer)
An adhesive composition for re-peeling prepared on both surfaces (wire surface and felt surface) of a high-quality paper having a basis weight of 95 g / m ^{2 so} as to have the following formulation is 7 g / m ² per solid using an air knife coater. Coating and drying were performed to obtain a pressure-sensitive adhesive sheet for electrophotographic printing.

[Adhesive composition formulation for removable adhesive]
Dispersion A: 0.8 part Adhesive A: 35 parts [Adhesive obtained by graft polymerization of 25% methyl methacrylate on natural rubber (product name: 35-018A, manufactured by NSC Japan)]
Binder: 10 parts [SBR (manufactured by Nippon A & L, trade name: SR-100)]
Starch: 36.2 parts [wheat starch (manufactured by Kashiwajima Starch, trade name: snow of agate, average particle size 11 μm)]
Silica: 18 parts [synthetic silica (made by Tokuyama, trade name: Fine Seal X-45)]

Example 2
[Production of fatty acid dispersion]
350 g of stearic acid powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a stearic acid dispersion having a solid content of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 20 to 30 ° C. in a disk type bead mill using glass beads having a diameter of 2 mm. The average particle diameter of the obtained stearic acid dispersion was 6.3 μm. This dispersion is referred to as Dispersion B.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion liquid A was changed to the dispersion liquid B.

Reference example 1
[Production of fatty acid salt dispersion]
350 g of calcium stearate powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a calcium stearate dispersion having a solid concentration of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 60 to 80 ° C. in a disk type bead mill using glass beads having a diameter of 5 mm. The average particle diameter of the obtained calcium stearate dispersion was 10.6 μm. This dispersion is referred to as Dispersion C.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion liquid A was changed to the dispersion liquid C.

Reference example 2
[Production of fatty acid salt dispersion]
350 g of calcium stearate powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a calcium stearate dispersion having a solid concentration of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 20 to 30 ° C. in a disk type bead mill using glass beads having a diameter of 2 mm. The average particle diameter of the obtained calcium stearate dispersion was 6.6 μm. This dispersion is referred to as Dispersion D.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion A was changed to the dispersion D.

Comparative Example 1
[Production of fatty acid dispersion]
350 g of stearic acid powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a stearic acid dispersion having a solid content of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 60 to 80 ° C. in a disk type bead mill using glass beads having a diameter of 0.1 mm. The average particle diameter of the obtained stearic acid dispersion was 0.07 μm. This dispersion is referred to as Dispersion E.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion A was changed to the dispersion E.

Comparative Example 2
[Production of fatty acid dispersion]
350 g of stearic acid powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a stearic acid dispersion having a solid content of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 20 to 30 ° C. in a disk type bead mill using glass beads having a diameter of 20 mm. The average particle diameter of the obtained stearic acid dispersion was 22 μm. This dispersion is designated as Dispersion F.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion A was changed to the dispersion F.

Comparative Example 3
[Production of fatty acid salt dispersion]
350 g of calcium stearate powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a calcium stearate dispersion having a solid concentration of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 60 to 80 ° C. in a disk type bead mill using glass beads having a diameter of 0.1 mm. The average particle diameter of the obtained calcium stearate dispersion was 0.08 μm. This dispersion is referred to as Dispersion G.

Comparative Example 4
[Production of fatty acid salt dispersion]
350 g of calcium stearate powder, 50 g of polyoxyethylene octylphenyl ether and 600 g of water were mixed to obtain a calcium stearate dispersion having a solid concentration of 40%. This dispersion was pulverized by circulating for 12 hours at a disk peripheral speed of 10 m / s and a temperature of 20 to 30 ° C. in a disk type bead mill using glass beads having a diameter of 20 mm. The average particle diameter of the obtained calcium stearate dispersion was 24 μm. This dispersion is designated as Dispersion H.

(Formation of releasable adhesive layer)
A pressure-sensitive adhesive sheet for electrophotographic printing was obtained in the same manner as in Example 1 except that the dispersion A was changed to the dispersion H.

Comparative Example 5
Electrophotographic printing feel in the same manner as in Example 1 except that the dispersion A was “SN DALACT 1001W” (trade name, polyethylene wax, solid content 40%, average particle size 10 μm, manufactured by San Nopco). A pressure-bonding sheet was obtained.

Comparative Example 6
Electrophotographic printing was performed in the same manner as in Example 1 except that the dispersion A was “Cerosol 686” (trade name, paraffin wax, solid content 50%, average particle size 0.5 μm, manufactured by Chukyo Yushi Co., Ltd.). A pressure sensitive adhesive sheet was obtained.

Comparative Example 7
Based on Example 1 of JP-A-2005-13997, 50 parts of adhesive A, 5 parts of binder, 0 part of wheat starch, silica [Mizukasil P-78A, manufactured by Mizusawa Chemical Co., Ltd., average particle This was carried out except that 35 parts of 0.5 μm in diameter] and 10 parts of wax emulsion “Cerosol 686” (trade name, paraffin wax, solid content 50%, average particle diameter of 0.5 μm, manufactured by Chukyo Oil & Fats Co., Ltd.) were used. In the same manner as in Example 1, a pressure-sensitive adhesive sheet for electrophotographic printing was obtained.

  Table 1 summarizes the materials used in the examples and comparative examples.

"Evaluation methods"
(1) Evaluation of metal roll stains during the confidential postcard base paper manufacturing process The state of metal roll stains was visually evaluated.
○: No metal roll contamination occurs.
Δ: Slight metal roll contamination occurs but does not affect the printed surface.
X: Metal roll contamination occurs and affects the printed surface.

(2) Evaluation of Turn Bar Dirt A pressure sensitive adhesive sheet for electrophotographic printing was printed for 5,000 m on a form printing machine (MVF18B manufactured by Miyakoshi), and the situation of the turn bar dirt was visually evaluated.
○: No turnbar contamination occurs.
Δ: Turnbar smudge occurs slightly but does not affect the printed surface.
X: Turnbar contamination occurs and affects the printed surface.

(3) Evaluation of impression cylinder stain at the time of printing A pressure sensitive adhesive sheet for electrophotographic printing was printed by a form printer (MVF18B, manufactured by Miyakoshi Co., Ltd.) for 5,000 m, and the situation of impression cylinder stain was visually evaluated.
○: No impression cylinder contamination occurs.
Δ: Impression cylinder contamination occurs slightly, but does not affect the printed surface.
×: Impression stains occur and affect the printed surface.

(4) Evaluation of pressure drum stains during dry sealer pressure bonding Dry sealer 6860 set in memory 18 (equivalent to 180 μm) by superposing pressure-sensitive adhesive sheet for electrophotographic printing on Z-fold [manufactured by Toppan Forms Co., Ltd. ], 30000 sheets were pressure-bonded, and the state of the impression cylinder dirt was visually evaluated.
○: No impression cylinder contamination occurs.
Δ: Impression cylinder contamination occurs slightly, but does not affect printing / printing surface.
×: Impression stains occur, affecting printing and printing surface.

(5) Suitability of laser printer Using a high-speed laser printer (SX7300, manufactured by Showa Information Equipment Co., Ltd.), a test character pattern was printed for 5,000 m, and the dirt state of the toner fixing roll was visually evaluated.
○: No toner fixing roll contamination occurs.
Δ: The toner fixing roll is slightly stained but does not affect the printing / printing surface.
X: Toner fixing roll stain occurs and affects printing and printing surface.

(6) Inkjet printability Test character patterns were printed using an inkjet printer (Deskjet 560J, manufactured by Hewlett-Packard Company) and black ink (Cytex 1040), and the character recognition status was visually evaluated.
○: There is no bleeding, and the printing situation is clear.
Δ: Slight bleeding but character can be identified.
X: There is bleeding and characters cannot be identified.

(7) Comprehensive evaluation Comprehensive evaluation as confidential postcard paper was performed.
○: Excellent as confidential postcard paper.
Δ: There is a possibility of causing a problem as confidential postcard paper.
X: Not suitable as confidential postcard paper.

  The above evaluation results are summarized in Table 2.

As shown in Table 2, in the examples containing stearic acid particles , dirt adheres to the metal roll during the confidential postcard manufacturing process, the impression cylinder of the foam printing machine during the printing process, and the impression cylinder of the dry sealer during the crimping process. It was excellent.

Claims (8)

An adhesive, the adhesive composition having an average particle size containing a stearic acid granules child and starch particles of 0.1 to 20 [mu] m, usually no adhesive, pressure in a state of being opposed to the adhesive layer to each other Manufacture of a pressure-sensitive adhesive sheet for electrophotographic printing comprising forming a releasable adhesive layer on at least one surface of a substrate sheet that can be bonded by treatment and can be peeled off after bonding. Method.   At least the other surface of the substrate sheet surface on which the releasable adhesive layer is formed is usually not adhesive and can be adhered by pressure treatment with the adhesive layers facing each other, and re-peeling. The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to claim 1, comprising forming an adhesive layer for permanent adhesion having no property. The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to claim 1 or 2, wherein a blending amount of the stearic acid particles in an adhesive composition for a releasable adhesive layer is 0.1 to 5% by mass. .   The starch particles are particles having an average particle size of 5 to 30 μm selected from wheat starch, potato starch and tapioca starch, and the blending amount in the adhesive composition for the releasable adhesive layer is 10% by mass to 60% by mass. The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to any one of claims 1 to 3.   In the adhesive composition, as a binder, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose derivative, starch derivative, etc., aqueous emulsion type polymer latex, SBR latex, NBR latex, MBR latex, polyvinyl acetate, The feeling for electrophotographic printing according to any one of claims 1 to 4, comprising at least one selected from an acrylic resin, a styrene-acrylic copolymer, an ethylene-vinyl acetate polymer, polyvinyl butyral, and polyurethane. A method for producing a pressure-bonding sheet.   The method for producing a pressure-sensitive adhesive sheet for electrophotographic printing according to any one of claims 1 to 5, wherein particles of an inorganic pigment or an organic pigment are blended in the adhesive composition as an adhesive force control agent.   The said base material sheet is 1 type chosen from fine paper, medium quality paper, art paper, a coated paper, a synthetic paper, a synthetic resin film, metal foil, and a nonwoven fabric, The any one of Claims 1-6. A method for producing a pressure-sensitive adhesive sheet for electrophotographic printing.   It is produced by the manufacturing method according to any one of claims 1 to 7, and usually has no adhesiveness, and can be bonded by pressure treatment with the adhesive layers facing each other, and A pressure-sensitive adhesive sheet for electrophotographic printing having a releasable adhesive layer from which the adhesive layers after bonding can be peeled off.