JP6740183B2 - Ink jet recording paper and method for manufacturing the same - Google Patents

Description

The present invention relates to an inkjet recording pressure-sensitive adhesive sheet suitable for printing by an inkjet printer, and more particularly to an inkjet recording pressure-sensitive adhesive sheet suitable for printing by an inkjet printer using a pigment-type water-based ink.

Pressure sensitive adhesive is printed by printing confidential information, advertisement information, etc. on the surface, folding the paper so that the pressure sensitive adhesive coated surface is the inner surface, and crimping and sealing by applying a predetermined pressure. Paper is used for various purposes. For the purpose of reducing the cost of mailing, such pressure-sensitive adhesive paper is re-separable and pressure-sensitive with the printed side of the personal information inside, and is used as a postcard (hereinafter abbreviated as pressure-bonded postcard) to be used as a substitute for a letter, or by mailing or mailing. It is also used in various fields as crimp printed materials such as crimp advertisements distributed in places such as.

An example of the method for manufacturing the pressure-bonded paper is as follows. First, a pressure-sensitive adhesive composition that can be adhered to and re-peeled by applying a certain pressure is applied to the surface of the base paper, and common information such as fixed information such as frame and sender information is UV-curable. Print on the form printing machine with the ink. Next, personal information (confidential information), which is variable information, is printed by various printers, the paper is folded into two or three, and then the pressure sensitive adhesive composition is applied by passing it between pressure rolls of a dry sealer. The surfaces provided are adhered to each other to be provided to the user. Here, if the paper is cut into a postcard size, it becomes a pressure-bonded postcard. After receiving the pressure-bonded paper or the pressure-bonded postcard, the recipient peels off the coated surface of the pressure-sensitive adhesive that has been bonded and reads the confidential information printed inside.

In the crimping paper manufacturing process, the crimping paper is stored in a state in which fixed information (common information) is printed together on the crimping paper in advance, and the confidential information is printed by using the saved crimping paper as much as necessary. It is generally provided to. For this reason, it is often the case that the ink used for printing the fixed information is weather resistant after printing the fixed information and before the confidential information is printed and provided to the customer. Generally, UV curable ink is used.

By the way, an ink jet printer prints by ejecting ink innumerable droplets by various means and adhering it to a recording sheet, but in recent years, technical progress has been remarkably fast. It has become possible, and colorization has become easier. As a result, it has become possible to obtain images that are comparable to multi-color offset printing and color electrophotographic systems. In addition, inkjet printers have a running cost in color printing that is higher than that of electrophotographic systems. It is also widely used because it is cheaper than other printers. For these reasons, inkjet printers have been increasingly used in recent years for printing confidential information on pressure-bonded paper.

The use of inkjet recording paper is expanding to posters and drafting applications.Therefore, inkjet recording paper and ink for inkjet recording are required to have more chromaticity, color reproducibility and weather resistance of images than ever before. It is designed to be used. In response to such demands, improvements in inkjet recording inks and base materials (inkjet recording papers) have progressed, and recently, in addition to conventionally known aqueous dye inks, aqueous pigment inks in which coloring material pigments are dispersed in water are also used. As a result, the above-mentioned suitability for requirements is being addressed.

Among these aptitudes, the improvement of the weather resistance by using the water-based pigment ink has made it possible to print the fixed information by an inkjet printer instead of the form printing by the UV curable ink. Therefore, by printing fixed information and confidential information at the same time with an inkjet printer, the form printing process can be reduced, which is expected to lead to a large cost improvement.

On the other hand, there are still some problems in using the water-based pigment ink for the pressure-sensitive adhesive recording paper for inkjet recording, and it is necessary to add new aptitude to the pressure-sensitive adhesive paper in order to cope with these problems. Specifically, it is as follows.

(1) High color density Since the coloring material pigment in the aqueous pigment ink is insoluble in water unlike the coloring material dye, it is necessary to increase the ratio of the coloring material pigment too much in order to stably disperse the coloring material pigment in the ink. It is difficult to obtain clear color. Also, as one method of increasing the color density, there is a method of increasing the compounding ratio of a filler such as silica having high ink absorbency, but in order to maintain an appropriate adhesive force as a pressure-bonded postcard, the printing surface (pressure-bonded paper In the case of (1), it is not preferable to increase the blending amount of the filler in the pressure-sensitive adhesive coating layer) to the level of general inkjet recording paper.

(2) Improving ink fixability (preventing print transfer when opened)
The color material pigment in the water-based pigment ink has a poorer absorbability into the coating layer of the pressure-sensitive adhesive composition than the color material dye, and the color material pigment is likely to remain on the coating layer. Therefore, the coloring material pigment remaining on the coating layer is transferred to the facing surface while being pressed and held as it is with the dry sealer, and when the pressure-sensitive postcard is peeled off, the transferred coloring material pigment makes it possible to read characters and barcodes. There is a problem that it becomes difficult.

(3) Improvement of surface strength (prevention of stain on pressure roll of dry sealer)
Increasing the blending ratio of a highly water-absorbing filler such as silica to absorb a water-absorbing pigment ink having poor absorptivity causes the coating layer strength of the printed coating layer to be weak when the ink adhesion amount is increased. On the other hand, when the pressure-bonded paper is pressure-bonded with the dry sealer to perform the sealing treatment, the coloring material pigment is peeled off by the pressure roll of the dry sealer to stain the roll, and if this state continues, it accumulates on the pressure roll. There is a problem that dirt stains the pressure-bonded paper.

In order to solve these problems, various proposals have heretofore been made regarding pressure-sensitive adhesive paper for inkjet recording. For example, in Patent Document 1, 5 to 25 colloidal fine particles such as silica and calcium carbonate having an average particle diameter of 1 to 100 nm are used with respect to 100 parts by mass of a styrene-methyl methacrylate graft copolymerized natural rubber adhesive base (solid content). By using a pressure-sensitive adhesive composition containing parts by mass, an information-carrying sheet having excellent fixability and water resistance of inkjet ink has been proposed (see Patent Document 1).

Further, it contains amorphous silica having an apparent specific gravity of 0.25 g/ml or more measured according to JIS K 6220 as a fine particle filler of the adhesive layer, and the amorphous silica content in the adhesive layer is By setting the content to 20 to 50% by mass, a pressure-sensitive adhesive sheet excellent in suitability for a high-speed inkjet printer has been proposed (see Patent Document 2).

In addition, the pseudo adhesive layer contains a non-peelable adhesive containing natural rubber as a main component, a completely saponified polyvinyl alcohol, and a fine particle filler, and the fine particle filler is a precipitated synthetic silica and a gel synthetic silica. By adjusting the blending mass ratio of 9:1 to 7:3, offset printing suitability, recording density in ink jet recording, bleeding of printing (feathering), drying of ink while satisfying the adhesion and peeling characteristics. A pseudo-adhesive paper has been proposed, which has improved absorbency, water resistance of ink, and transferability of a printing portion at the time of pressure bonding (see Patent Document 3).

Moreover, even if the pseudo-adhesive layer is a pseudo-adhesive sheet for printing a pigment ink containing a fine particle filler together with an adhesive, and the precipitation method silica is used as the fine particle filler, even if the pigment ink is used for printing. A pseudo-adhesive sheet for pigment ink printing has been proposed in which there is no risk of rubbing stains and the like, and the surface strength of the pseudo-adhesive layer provided on the surface of the base sheet is not weakened (see Patent Document 4). ).

JP, 2001-262105, A JP, 2004-082466, A JP, 2009-249745, A JP, 2013-212671, A

However, in the methods described in Patent Documents 1 and 2, when applied to a high-speed inkjet printer using an aqueous pigment ink, sufficient surface strength and ink fixing effect cannot be obtained. For this reason, it has not been possible to provide ink stain prevention and non-transferability in the dry sealer.

Further, in the methods described in Patent Documents 3 and 4, when the method is applied to a high-speed inkjet printer using an aqueous pigment ink, it is not possible to provide a sufficiently high color density of an image. ..

Further, in these documents, it cannot be said that the blocking countermeasure is sufficient. If blocking occurs in the state of a roll of paper (hereinafter, also referred to as a roll), the roll feeding becomes unstable, and paper breakage may occur. An explanatory view of the roll feeding in the state without blocking is shown in FIG. 4, and an explanatory view of the roll feeding in the state with blocking is shown in FIG. 5, respectively. It should be noted that all of these drawings schematically show the state of roll feeding from the side direction. In both figures, 1 is a pressure-sensitive paper roll, 2 is a feeding part, 3 is a blocking part, and 4 is a feeding position in a normal state. When the pressure-bonded paper roll 1 is not blocked, the pressure-bonded paper roll is fed from a certain position of the roll in the feeding direction indicated by the arrow (FIG. 4). On the other hand, in the state where the pressure-bonded paper roll 1 is blocked, the pressure-bonded paper is difficult to separate from the blocking unit 3, so that the roll feeding position is lower than the normal feeding position 4 (FIG. 5A), and the feeding unit is further extended. Since the sheet 2a returns to the normal feeding position 4 so as to be able to flip even when it is peeled from the blocking portion 3, the sheet flaps by several millimeters to several centimeters (FIG. 5(b)), and the sheet is likely to meander or break. .. Even if blocking occurs on the entire sheet, the degree of adhesion due to blocking varies depending on the part, so that stable running does not occur and roll running is unstable.

The present invention has been made to solve the above-mentioned problems, and when printed with an ink jet printer using an aqueous pigment ink, it has excellent color density of printing, and moreover, it has excellent ink fixability. An object of the present invention is to provide a pressure-sensitive adhesive sheet for inkjet recording, in which the print content is not transferred to the opposite surface.

Another object of the present invention is that the pressure-sensitive adhesive coating layer has excellent surface strength and does not stain the pressure roll of the dry sealer when the pressure-sensitive postcard is sealed with the dry sealer. To provide pressure-sensitive adhesive paper for inkjet recording

Another object of the present invention is to provide a pressure-sensitive adhesive sheet for inkjet recording in which blocking is less likely to occur.

Further, other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description.

In order to solve the above-mentioned problems, the pressure-sensitive adhesive sheet for inkjet recording according to the present invention has a non-peeling pressure-sensitive adhesive base, an inorganic pigment, starch particles, a binder, and a water-soluble polyvalent resin on at least one surface of the base paper. A pressure-sensitive adhesive paper for ink-jet recording having a pressure-sensitive adhesive coating layer containing a metal salt, the intermediate saponification type polyvinyl alcohol having a saponification degree of 90 to 98 mol% and gelatinized starch as the binder, Moreover, it is used for an ink jet printer using an aqueous pigment ink.

The gelatinized starch referred to here means that a starch powder in the form of powder particles (β starch) is heated or made alkaline to expand the starch particles until the starch particles disintegrate to give a transparent or viscous starch. It refers to a translucent starch paste, and is generally called pregelatinized starch. For example, a slurry obtained by mixing powdery granular starch (β starch) and water is heated with stirring, kept at 95° C. or higher for 30 minutes or more, and then cooled. It can also be made into a powder by drying, and this powdered gelatinized starch swells and dissolves in cold water. Further, the starch particles are powdery granular starch (β starch), which is different from gelatinized starch, and can be confirmed as particles in the pressure-sensitive adhesive coating layer.

With such a configuration, the color density of the surface of the pressure-sensitive adhesive coating layer (hereinafter, abbreviated as “color-forming property”) is high, and the surface of the print recorded on the confidential surface at the time of peeling after pressure bonding with the dry sealer The transfer (hereinafter, abbreviated as "print transfer to the opposite surface") is suppressed, and the adhesion of the printed pressure-sensitive adhesive coating layer to the pressure roll of the dry sealer (hereinafter, (Abbreviated as "dirt of pressure roll") is suppressed. In particular, by adding an intermediate saponified polyvinyl alcohol having a saponification degree of 90 to 98 mol %, the transfer of print to the facing surface is significantly suppressed.

Further, the addition of starch particles to the pressure-sensitive adhesive coating layer suppresses the occurrence of blocking, and the addition of gelatinized starch improves the surface strength of the coating layer. The print transfer to the opposite surface is further suppressed.

In the pressure-sensitive adhesive paper for inkjet recording of the present invention, it is sufficient that the pressure-sensitive adhesive coating layer provided on at least one surface satisfies the above conditions, and the other surface has the same pressure-sensitive adhesive composition. A composition such as an agent coating layer, a pressure-sensitive adhesive coating layer having a different configuration, a pressure-sensitive adhesive coating layer not provided, or the like may be appropriately adopted.

Further, in a preferable actual form of the present invention, the binder may be an intermediate saponification type polyvinyl alcohol having a saponification degree of 92 to 96 mol %.

According to such a configuration, the saponification degree of polyvinyl alcohol is more limited, so that it is possible to further suppress the print transfer to the facing surface.

Further, in a preferred embodiment of the present invention, the gelatinized starch may be a phosphoric acid esterified starch.

According to such a configuration, the ink fixing property is excellent, and the print transfer to the facing surface can be further suppressed.

In a preferred embodiment of the present invention, the content of the non-peeling pressure-sensitive adhesive may be in the range of 95 to 170 parts by mass with respect to 100 parts by mass of the inorganic pigment.

According to such a configuration, since the amount of the non-peeling pressure-sensitive adhesive base compounded is in an appropriate range, transfer to the facing surface is less likely to occur, and ink absorbency, fixability, and color developability are also improved. improves.

In a preferred embodiment of the present invention, the inorganic pigment may contain amorphous silica.

According to such a structure, since the amorphous silica is porous and has a high absorbing ability for the aqueous pigment ink, it is possible to obtain the pressure-sensitive adhesive sheet for inkjet recording which is more excellent in the ink absorbing property and the ink fixing property.

Further, in a preferred embodiment of the present invention, the inorganic pigment may contain gel method silica.

With such a configuration, the strength of the coating layer is further improved, so that even when printing ruled lines and general information by form printing with UV curable ink, the blanket, the plate, etc. are less likely to be contaminated for inkjet recording. It can be paper.

In a preferred embodiment of the present invention, the oil absorption of the amorphous silica measured according to ISO 787-5 may be in the range of 180 to 400 ml/100g.

With such a configuration, it is possible to obtain a pressure-sensitive adhesive sheet for inkjet recording, which is more excellent in the color developability of an image and has good ink absorbability and ink fixability.

In a preferred embodiment of the present invention, the average particle size of the amorphous silica measured by a laser diffraction method may be in the range of 1.0 to 15.0 μm.

With such a configuration, the adhesive strength of the coating layer surface and the coating layer strength are excellent, and stains on the pressure roll of the dry sealer and print transfer to the facing surface are further suppressed.

In a preferred embodiment of the present invention, as the starch particles, starch particles having an average particle size of 10 to 20 μm by a laser diffraction method are further contained in a solid content of 10 to 30% by mass with respect to the inorganic pigment. May be included.

According to such a configuration, the adhesive strength is appropriately adjusted, the print transfer to the facing surface is further suppressed, and the occurrence of blocking is also suppressed.

In a preferred embodiment of the present invention, the content of the gelatinized starch may be in the range of 2.5 to 18% by mass in terms of solid content with respect to the inorganic pigment.

According to such a configuration, the content of the gelatinized starch is in the appropriate range, so that the print transfer to the facing surface is further suppressed.

In a preferred embodiment of the present invention, the tsubo may be 60 to 200 g/m ² . With such a configuration, it is possible to provide a pressure-sensitive adhesive sheet for inkjet recording, which is suitable for use as a postcard sheet.

The present invention can also be understood as a method for manufacturing a pressure-sensitive adhesive sheet for inkjet recording.

A method for producing a pressure-sensitive adhesive paper for inkjet recording according to the present invention comprises a step of preparing a base paper, a pressure-sensitive adhesive containing a non-peeling pressure-sensitive adhesive base, an inorganic pigment, starch particles, a binder, and a water-soluble polyvalent metal salt. A step of adjusting a pressure-sensitive adhesive composition using an adhesive composition raw material, and a pressure-sensitive adhesive coating layer by coating the pressure-sensitive adhesive composition on at least one surface of the base paper. And a gel method silica is included as the inorganic pigment, and the binder includes an intermediate saponified polyvinyl alcohol having a saponification degree of 90 to 98 mol% and gelatinized starch. It is a thing.

According to such a configuration, the color density of printing is high, the transfer of printing to the facing surface is suppressed, and the pressure-sensitive adhesive sheet for inkjet recording that does not stain the pressure roll of the dry sealer can be easily manufactured.

The pressure-sensitive adhesive paper for inkjet recording according to the present invention has a high color density and the pressure-sensitive adhesive coating layer has sufficient surface strength, so that the transfer of printing to the opposite surface is suppressed even when the water-based pigment ink is used. Therefore, the pressure roll does not become dirty when pressure-bonded with a dry sealer.

Also, by selecting the most suitable inorganic pigment to be added to the pressure-sensitive adhesive composition, the surface strength of the pressure-sensitive adhesive composition coating layer will be sufficiently high. Due to the high surface strength, it is possible to print fine line images favorably, and even when using water-based pigment ink, high ink fixability is obtained, good color development, and print transfer to the opposite surface. Further, dirt on the pressure roll and the like are further suppressed.

1 is a chart showing the composition of a pressure-sensitive adhesive sheet for inkjet recording obtained in an example. 3 is a chart showing the composition of a pressure-sensitive adhesive sheet for inkjet recording obtained in a comparative example. It is a chart showing the physical property evaluation results of the pressure-sensitive adhesive paper for inkjet recording obtained in Examples and Comparative Examples. It is a figure explaining the delivery of the roll in the state without blocking. It is a figure explaining the delivery of the roll in the state with blocking.

Hereinafter, preferred embodiments of the present invention will be described in detail, but the present invention is not limited to the following description.

As described above, when printing on an inkjet recording pressure-bonded paper with an inkjet printer, the inkjet ink ejected from the ink nozzles first becomes droplets and adheres to the paper surface, and then the dye/ The pigment penetrates and fixes inside the paper. When a water-based pigment ink is used here, since the color material pigment in the water-based pigment ink has poor absorbability into the pressure-sensitive adhesive coating layer, only the water content in the ink penetrates into the paper and the color material pigment Tends to remain on the surface of the pressure-sensitive adhesive coating layer. If the absorption and fixing of the coloring material pigment remaining on the surface of the pressure-sensitive adhesive coating layer is insufficient, there arises a problem of print transfer to the facing surface. Further, when the ink adhesion amount is increased in order to improve the color developability with the aqueous pigment ink, the coating layer may not sufficiently absorb the ink, which may cause a problem of stains on the pressure roll.

In order to solve these problems, the pressure-sensitive adhesive sheet for inkjet recording according to the present invention has the following configuration.

The pressure-sensitive adhesive paper for inkjet recording according to the present invention comprises a base paper and a pressure-sensitive adhesive coating layer made of a pressure-sensitive adhesive composition provided on at least one surface of the base paper. In the present invention, various types of information paper such as kraft paper, foam paper, high-quality paper, medium-quality paper, and OCR paper can be appropriately used as the base paper for the pressure-sensitive adhesive paper for inkjet recording. Commercially available paper may be used as these papers, but when manufactured from pulp, a wet paper strength enhancer or the like may be added to impart water resistance, if necessary. Here, the fiber raw material of the base paper is not particularly limited, and general wood pulp can be appropriately selected and used, but in consideration of the environment, waste paper generated in the process, waste paper pulp and kenaf, Non-wood materials such as bagasse and bamboo may be used.

In the present invention, the rice basis weight of the inkjet recording pressure-sensitive adhesive paper is not particularly limited, but it is preferably in the range of 60 to 200 g/m ² in consideration of processing into the pressure-sensitive postcard paper, and detailed rice The tsubo is selected so as to satisfy the postcard weight standard in the postal method, and the weight is set to be in the range of 2 to 6 g in the case of a pressure-bonded postcard.

In the present invention, the "pressure-sensitive adhesive composition" is a composition which is not adhered in a normal state but is adhered by pressurization, and can be peeled off by manual peeling after pressurization. A non-releasing adhesive base that bears the effect, starch particles that contribute to adjusting the adhesive strength, an inorganic pigment that contributes to ink absorption, and a binder that contributes to the surface strength of the pressure-sensitive adhesive coating layer. The main component is a water-soluble polyvalent metal salt that imparts ink fixability.

Here, examples of the non-peeling pressure-sensitive adhesive base that can be used in the pressure-sensitive adhesive composition include natural rubber-based latex and synthetic rubber latex. As natural rubber latex, natural rubber latex obtained by graft-polymerizing methyl methacrylate and styrene to natural rubber, natural rubber latex mixed with natural rubber and methyl methacrylate, natural rubber latex and protection A mixture with a colloidal acrylic copolymer emulsion or the like can be preferably used because it is easy to develop an appropriate adhesive ability. Examples of synthetic rubber latex include styrene-butadiene latex and acrylonitrile latex. These latexes can be used alone or in admixture of two or more.

Further, in the present invention, the amount of the non-peeling pressure-sensitive adhesive base compounded is preferably in the range of 95 to 170 parts by mass with respect to 100 parts by mass of the inorganic pigment in terms of solid content. When the amount of the non-peeling pressure-sensitive adhesive base compounded is less than 95 parts by mass, sufficient adhesive force cannot be obtained because the amount of the non-peeling pressure-sensitive adhesive base compounded is small, and sealing is performed by pressure bonding. High pressure is required when performing the treatment. When the pressure-bonded postcard paper is sealed with a high pressure, a strong pressure is applied between the pressure-bonded opposite surfaces, and therefore the print content of the pressure-bonded surface may be transferred to the opposite surface when the peeling is performed again. On the other hand, when the amount of the non-peeling pressure-sensitive adhesive base compounded exceeds 170 parts by mass, the absorption ratio and fixing property of the ink are lowered because the compounding ratio of the inorganic pigment is relatively lowered, and the pressure-sensitive adhesive Since the coating layer cannot sufficiently and quickly fix the inkjet ink, there is a risk that the color developability will deteriorate.

In the present invention, the inorganic pigment to be added to the pressure-sensitive adhesive composition is not particularly limited, and known inorganic pigments such as kaolin, calcined kaolin, talc, calcium carbonate and amorphous silica may be used. it can. Among these, it is preferable to use amorphous silica because it has excellent ink absorbability.

Amorphous silica is porous and has a high absorptivity for water-based pigment inks. Therefore, when it is blended in a pressure-sensitive adhesive composition, the ink-absorption of the pressure-sensitive adhesive coating layer and the ink The fixability is improved, and it becomes possible to quickly absorb and fix the aqueous pigment ink. Here, the degree of ink absorption of amorphous silica can be evaluated by the amount of oil absorption, and it is generally considered that the absorption of inkjet ink increases as the amount of oil absorption increases.

The amorphous silica used in the present invention preferably has an oil absorption amount measured according to ISO 787-5 (hereinafter sometimes simply referred to as “oil absorption amount”) of 180 to 400 ml/100 g. More preferably 220 to 355 ml/100 g. By using such amorphous silica, it is possible to obtain a pressure-sensitive adhesive sheet for inkjet recording, which is excellent in color development of printed/printed images, has good ink absorbability and ink fixability, and has no print transfer when opened. ..

When the oil absorption of the amorphous silica is less than 180 ml/100 g, the ink absorbency becomes too weak and the color developability deteriorates, and the pressure-sensitive adhesive coating layer is provided with sufficient fixability of the aqueous pigment ink. It may not be possible, and print transfer to the facing surface may occur. When the oil absorption of the amorphous silica exceeds 400 ml/100 g, the ink absorbency becomes too strong, and even the adhesive is absorbed due to the excessive absorbency, and the pressure roll is soiled. There is a risk.

The average particle size of the inorganic pigment measured by the laser diffraction method is preferably 1.0 to 15.0 μm when amorphous silica is used. More preferably, it is 2.0 to 12.5 μm. By using an inorganic pigment having such an average particle diameter, the adhesive strength and the coating layer strength become preferable, and the stain on the pressure roll of the dry sealer and the print transfer to the facing surface are further suppressed, and the recording image by the inkjet printer is improved. The color developability of can be further improved.

If the average particle size of the inorganic pigment is less than 1.0 μm, the surface strength may be reduced, and print transfer to the facing surface may occur. On the other hand, if the average particle size of the inorganic pigment exceeds 15.0 μm, the particle size of the inorganic pigment itself may lose the smoothness on the surface of the coating layer, and print transfer to the facing surface may occur.

In the present invention, it is preferable to use gel method silica among the amorphous silica as the inorganic pigment. Amorphous silica is classified into a gel method silica and a precipitation method silica depending on the production method, but the gel method silica tends to improve the coating layer strength as compared with the precipitation method silica. Therefore, by containing gel method silica as an inorganic pigment, it is possible to obtain a pressure-sensitive adhesive sheet for inkjet recording which is unlikely to stain a blanket or a plate even when a ruled line or general information is printed by form printing using UV curable ink or the like. it can.

Further, in the present invention, starch particles are blended in the pressure-sensitive adhesive coating layer. As the starch particles, wheat starch, tapioca starch, corn starch, potato starch and the like can be used, and among these, wheat starch is preferable because many of them have the optimum particle size for suppressing blocking. ..

It is more preferable that the starch particles used here have an average particle diameter of 10 to 20 μm measured by a laser diffraction method. Further, the blending ratio is preferably in the range of 10 to 30 mass% in terms of solid content with respect to the inorganic pigment. By blending starch particles in the preferred range, the adhesive strength is properly adjusted to improve the print transfer to the facing surface, and the surface roughness of the pressure-sensitive adhesive coating is larger than that of amorphous silica alone. Occurs, the absorbability of the aqueous pigment ink is further improved, and the blocking is improved.

As described above, in the present invention, a binder is added to improve the strength of the pressure-sensitive adhesive coating layer. Here, as the binder, intermediate saponification type polyvinyl alcohol and gelatinized starch having a saponification degree of 90 to 98 mol %, more preferably 92 to 96 mol %, are used. Although the reason is not clear, when an intermediate saponification type polyvinyl alcohol having a saponification degree of 90 to 98 mol% and a water-soluble polyvalent metal salt are used in combination as a binder, the fixing property of the ink is improved and the ink is improved. The print transfer to the facing surface of the is suppressed. However, only by improving the fixability of the ink, when the coating layer strength is insufficient, the coating layer may be stripped off and the printed portion may be transferred to the facing surface together with the coating layer. Therefore, in the present invention, by adding gelatinized starch in addition to the above-mentioned two components, the strength of the pressure-sensitive adhesive coating layer is improved, whereby the transfer of print to the facing surface is further suppressed.

If the saponification degree of the intermediate saponification type polyvinyl alcohol exceeds 98 mol%, the absorption of the ink may be hindered and the ink may remain on the surface of the coating layer, probably because the coating property of the polyvinyl alcohol may be too high. Satisfaction of suppression of print transfer to the surface cannot be satisfied. On the other hand, when the saponification degree is less than 90 mol%, the ink drying property is impaired and the surface strength is also reduced. Furthermore, the adhesive performance of the pressure-sensitive adhesive coating layer will decrease. When the adhesive performance deteriorates, pressure bonding at a higher pressure is required to give an appropriate bonding strength as a pressure-bonded postcard. Print transfer is likely to occur.

The content of the intermediate saponification type polyvinyl alcohol having a saponification degree of 90 to 98 mol% in the pressure-sensitive adhesive coating layer is preferably 24 to 48 mass% in terms of solid content with respect to the inorganic pigment, and 28 to It is more preferably 40% by mass. If the content of the intermediate saponified polyvinyl alcohol having a saponification degree of 90 to 98 mol% exceeds 48% by mass, the absorptivity of the aqueous pigment ink may be hindered, and the suppression of print transfer to the facing surface may not be satisfied. is there. On the other hand, if it is less than 24% by mass, the strength of the pressure-sensitive adhesive coating layer may be insufficient, and the pressure roll may not be prevented from being soiled.

As the gelatinized starch used in the present invention, phosphoric acid esterified starch, oxidized starch, cationized starch, hydroxyethylated starch and the like can be used, but since phosphorus has a high ability to suppress print transfer to the facing surface, Acid esterified starch is preferred.

The content of gelatinized starch in the pressure-sensitive adhesive coating layer is preferably 2.5 to 18% by mass in terms of solid content with respect to the inorganic pigment, and more preferably 3.3 to 17% by mass. preferable. If the content of the gelatinized starch exceeds 18% by mass, the absorbability of the water-based pigment ink may be impaired, and the suppression of print transfer to the facing surface may not be satisfied. On the other hand, if it is less than 2.5% by mass, the strength of the pressure-sensitive adhesive coating layer is insufficient, and the transfer of printing to the facing surface is likely to occur.

Further, as the binder, within a range that does not impair the intended effect of the present invention, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, acrylic resin, polyvinyl acetate resin, ethylene-vinyl acetate resin, etc. Can be used in combination. Further, various modified polyvinyl alcohols such as silanol-modified, carboxyl group-modified, acetoacetyl group-modified, and cation-modified may be used.

In the present invention, in addition to the main component of the pressure-sensitive adhesive composition, a water-soluble polyvalent metal salt is added to the pressure-sensitive adhesive composition as an ink fixing agent. Examples of the water-soluble polyvalent metal salt include hydrochloric acid, nitric acid and sulfate of calcium and magnesium. Among these, magnesium sulfate and/or calcium chloride is preferable, and magnesium sulfate is more preferable, because it has excellent ink fixability and can suppress print transfer to the facing surface. In addition, the amount of the water-soluble polyvalent metal salt to be added varies depending on the type, but in the case of magnesium sulfate, for example, it should be in the range of 0.5 to 23 mass% in terms of solid content with respect to the inorganic pigment. Is preferred. More preferably, it is 0.8 to 19 mass %. Further, in the case of calcium chloride, it is preferably in the range of 0.1 to 20% by mass, more preferably 3 to 15% by mass. Incorporation of a water-soluble polyvalent metal salt can improve the color developability of ink and prevent bleeding. This is because the water-soluble polyvalent metal salt fixes the coloring material pigment in the water-based pigment ink on the surface of the pressure-sensitive adhesive coating layer, and at the same time, the ink solvent component is absorbed in the coating layer to develop the ink color. This is because the property is improved and ink bleeding is suppressed. Further, in order to use it as a co-paper for water-based dye/pigment ink, dimethylamine/epihalohydrin polycondensation, which is an oligomer or polymer of primary to tertiary amine or quaternary ammonium salt within a range that does not impair the effects of the present invention. You may use together the cationic resin which has as a main component the thing, an acrylamide-diallylamine copolymer, a polyvinylamine copolymer, dicyandiamide, dimethyl diallyl ammonium chloride.

Here, if the amount of the water-soluble polyvalent metal salt is too small, the ink does not fix, and thus the color developability of the ink deteriorates, and if the amount of the water-soluble polyvalent metal salt is too large, the fixation with the ink becomes too good and the ink aggregated on the surface of the coating layer. If it remains, it may not be possible to satisfy the suppression of print transfer to the facing surface.

In the pressure-sensitive adhesive composition of the present invention, other known additives used in the technical field may be appropriately used, if necessary. Examples of such an additive include a defoaming agent, a thickener, a pH adjuster, a lubricant, a dispersant, a wetting agent, a dye, an antiaging agent, a preservative, and the like. When using these additives, it is necessary to pay attention to the blending amount and the like so as not to impair the object of the present invention.

In the pressure-sensitive adhesive sheet for inkjet recording of the present invention, the non-peeling pressure-sensitive adhesive composition is preferably applied in a range of 2.0 to 12.0 g/m ² in terms of solid content on one side of the base paper. If the coating amount is less than 2.0 g/m ² , the adhesive force after the pressure treatment by the dry sealer may be insufficient and the adhesive state may become unstable. On the other hand, if the coating amount exceeds 12.0 g/m ² , the strength of the non-peeling pressure-sensitive adhesive coating layer may be insufficient, and it may be impossible to suppress stains on the pressure roll. The coating device for forming the pressure-sensitive adhesive coating layer on the base paper is not particularly limited, and a known coating device used in the general coated paper manufacturing field can be appropriately used. For example, a blade coater, an air knife coater, a roll coater, a reverse roll coater, a curtain coater, a bar coater, a gravure coater, a size press coater, a bill blade coater, or the like can be used.

Examples of the pressure-sensitive adhesive sheet for inkjet recording according to the present invention will be specifically described below, but the present invention is not limited thereto. In addition, unless otherwise indicated, the part and% in each Example and a comparative example show a dry mass part and mass %. Further, the oil absorption amount of silica in each of the examples and comparative examples represents the oil absorption amount measured based on ISO 787-5, and the average particle size of the inorganic pigment and the starch particles in each example and the comparative example is a laser. The measured value of the volume average particle diameter by the diffraction method is shown.

[Preparation of gelatinized starch]
The gelatinized starch in each Example and Comparative Example was prepared by the following procedure. 30 parts by mass of powdery granular starch as a raw material and 70 parts by mass of water are mixed, and the resulting slurry is heated by adding water vapor to the slurry while stirring and holding the mixture at 90° C. or higher for 60 minutes, and then adding water. By performing cooling and adjusting the concentration, the gelatinized starch of the starting starch can be obtained. The solid content concentration of the obtained gelatinized starch was 17% by mass.

<Example 1>
Preparation of Pressure Sensitive Adhesive Composition: As an inorganic pigment, a gel method silica having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g (trade name: Syloid C-807/made by W. R. Grace Japan). ) 100 parts by mass and 2.8 parts by mass of an antifoaming agent are added to water and sufficiently dispersed, and then an intermediate saponification type polyvinyl alcohol having a saponification degree of 95.5 to 97.5 mol% (trade name) is used as a binder. : JM-17/Nippon Bibi Poval Co., Ltd.) 39 parts by mass and urea phosphate esterified starch (trade name: MS#4000/Nippon Shokuhin Kako Co., Ltd.) as a raw material 10 parts by mass gelatinized starch, non-peeling 4. After mixing 122 parts by mass of natural rubber-based latex obtained by polymerizing methyl methacrylate with natural rubber as the base of the pressure-sensitive adhesive, and adding 0.9 parts by mass of the higher fatty acid-based lubricant, magnesium sulfate as an ink fixing agent. 6 parts by mass and 16.7 parts by mass of wheat starch having an average particle diameter of 18 μm as starch particles were added to prepare a coating material as a pressure-sensitive adhesive composition.
Manufacturing method of pressure-sensitive adhesive paper for ink-jet recording: The prepared paint was applied to both sides of a foam paper of 113 g/m ² by using an air knife coater so that the coating amount on each surface was 6.0 g/m ² in terms of solid content. To obtain a pressure-sensitive adhesive sheet for inkjet recording.

<Example 2>
In Example 1, an intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Nippon Vineline Poval Co., Ltd.) was used as an intermediate saponified polyvinyl alcohol (trade name: 92.5 to 94.5 mol%). : JT-13Y/manufactured by Viet Nam Japan Poval Co., Ltd.) A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 3>
In Example 1, an intermediate saponification type polyvinyl alcohol (trade name: JM-17/manufactured by Japan Vinegar Poval Co., Ltd.) was used as an intermediate saponification type polyvinyl alcohol having a saponification degree of 93.5 to 95.5 mol% (trade name). : JM-33/manufactured by Viet Nam Bi Poval Co., Ltd.), and an ink jet recording pressure-sensitive adhesive paper was obtained in the same manner as in Example 1.

<Example 4>
In Example 1, an intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Japan Vine & Poval Co., Ltd.) was used as an intermediate saponified polyvinyl alcohol having a saponification degree of 96.0 to 98.0 mol% (trade name). : JM-23/manufactured by Nihon Bibi Poval Co., Ltd.) A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 5>
Same as Example 1 except that the amount of the intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Nippon Vine & Poval Co., Ltd.) was changed from 39 parts by mass to 28 parts by mass. Thus, a pressure-sensitive adhesive sheet for inkjet recording was obtained.

<Example 6>
In Example 1, except that the compounding amount of the intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Nippon Vine & Poval Co., Ltd.) was changed from 39 parts by mass to 33 parts by mass, the same as in Example 1. Thus, pressure-sensitive adhesive paper for inkjet recording was obtained.

<Example 7>
In Example 1, except that the compounding amount of the intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Japan Vine & Poval Co., Ltd.) was changed from 39 parts by mass to 45 parts by mass, the same as in Example 1. Thus, a pressure-sensitive adhesive sheet for inkjet recording was obtained.

<Example 8>
In Example 1, except that the amount of gelatinized starch made from urea phosphate esterified starch (trade name: MS#4000/Nippon Shokuhin Kako Co., Ltd.) as a raw material was changed from 10 parts by mass to 3.3 parts by mass. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 9>
In Example 1, except that the amount of gelatinized starch made from urea phosphate esterified starch (trade name: MS#4000/manufactured by Nippon Shokuhin Kako Co., Ltd.) was changed from 10 parts by mass to 7.7 parts by mass. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 10>

In Example 1, except that the amount of gelatinized starch using urea phosphate esterified starch (trade name: MS#4000/manufactured by Nippon Shokubai Co., Ltd.) as a raw material was changed from 10 parts by mass to 13.3 parts by mass. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 11>
In Example 1, except that the amount of gelatinized starch made from urea phosphate esterified starch (trade name: MS#4000/manufactured by Nippon Shokubai Co., Ltd.) was changed from 10 parts by mass to 16.7 parts by mass. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Example 12>
In Example 1, gel method silica having an average particle diameter of 7.0 μm and an oil absorption amount of 300 to 330 ml/100 g (trade name: Syloid C-807/W Are Grace Japan Co., Ltd.) having an average particle diameter of 12 μm is used. An ink jet recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the gel method silica (trade name: Syloid C-812/W Are Grace Japan Co., Ltd.) having an oil absorption of 300 to 330 ml/100 g was used. It was

<Example 13>
In Example 1, gel method silica having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g (trade name: Syloid C-807/produced by W. Grace Japan) was used. A pressure-sensitive adhesive paper for inkjet recording was obtained in the same manner as in Example 1 except that the gel method silica (trade name: HP39/PQ Corporation) having an oil absorption of 260 μm/100 g at 3 μm was used.

<Example 14>
In Example 1, gel method silica (trade name: Cyloid C-807/W Are Grace Japan Co., Ltd.) having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g was used. A pressure-sensitive adhesive paper for inkjet recording was obtained in the same manner as in Example 1 except that the gel method silica (trade name: 23D/PQ Corporation) having an oil absorption of 270 ml/100 g at 4 μm was used.

<Example 15>
In Example 1, gel method silica having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g (trade name: Syloid C-807/produced by W. R. Grace Japan) was used. Pressure bonding for ink jet recording in the same manner as in Example 1 except that the gel method silica (trade name: Syloid C-803/W Are Grace Japan Co., Ltd.) having an oil absorption of 300 to 330 ml/100 g at 0 μm was used. Got the paper.

<Example 16>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of wheat starch having an average particle diameter of 18 μm was changed from 16.7 parts by mass to 11.1 parts by mass. ..

<Example 17>
An ink jet recording pressure-sensitive adhesive paper was obtained in the same manner as in Example 1 except that the amount of wheat starch having an average particle diameter of 18 μm was changed from 16.7 parts by mass to 22.2 parts by mass. ..

<Example 18>
An ink jet recording pressure-sensitive adhesive paper was obtained in the same manner as in Example 1 except that the amount of wheat starch having an average particle diameter of 18 μm was changed from 16.7 parts by mass to 27.8 parts by mass. ..

<Example 19>
An ink jet recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the amount of magnesium sulfate was changed from 5.6 parts by mass to 1.1 parts by mass.

<Example 20>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of magnesium sulfate was changed from 5.6 parts by mass to 3.3 parts by mass.

<Example 21>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of magnesium sulfate was changed from 5.6 parts by mass to 11.1 parts by mass.

<Example 22>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of magnesium sulfate was changed from 5.6 parts by mass to 16.7 parts by mass.

<Example 23>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1, except that magnesium sulfate was changed to calcium chloride.

<Example 24>
In Example 1, gel method silica having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g (trade name: Syloid C-807/produced by W. R. Grace Japan) was used. An ink jet recording pressure-sensitive adhesive paper was obtained in the same manner as in Example 1 except that the precipitation method silica (trade name: Carplex FPS-1/manufactured by Evonik) having an oil absorption of 255 ml/100 g at 3 μm was used.

<Example 25>
In Example 1, gel method silica (trade name: Syloid C-807/W Are Grace Japan Co., Ltd.) having an average particle size of 7.0 μm and an oil absorption of 300 to 330 ml/100 g was used. A pressure-sensitive adhesive paper for inkjet recording was obtained in the same manner as in Example 1 except that the precipitation method silica (trade name: Carplex #30/manufactured by Evonik) having an oil absorption of 290 ml/100 g at 0 μm was used.

<Comparative Example 1>
In Example 1, an intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Japan Vine & Poval Co., Ltd.) was partially saponified polyvinyl alcohol having a saponification degree of 87.0 to 89.0 mol% (trade name). An ink jet recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the composition was changed to JP-18/Nippon Acetate Poval Co., Ltd.).

<Comparative example 2>
In Example 1, an intermediate saponification type polyvinyl alcohol (trade name: JM-17/manufactured by Japan Vine & Poval Co., Ltd.) was completely saponified type polyvinyl alcohol having a saponification degree of 99.3 mol% or more (trade name: V/ A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was changed to Nippon Vinegar Povar Co., Ltd.).

<Comparative example 3>
Example 1 was repeated, except that the amount of gelatinized starch made from urea phosphate esterified starch (trade name: MS#4000/Nippon Shokuhin Kako Co., Ltd.) was changed from 10 parts by mass to 0 parts by mass. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1.

<Comparative example 4>
In Example 3, the compounding amount of the intermediate saponified polyvinyl alcohol (trade name: JM-17/manufactured by Nippon Vineline Poval Co., Ltd.) was changed from 39 parts by mass to 49 parts by mass, and urea phosphate esterified starch (commercial product) was used. Name: MS#4000/manufactured by Nippon Shokubai Kako Co., Ltd. A pressure-sensitive adhesive sheet for inkjet recording was prepared in the same manner as in Example 1 except that the amount of gelatinized starch was changed from 10 parts by mass to 0 parts by mass. Obtained.

<Comparative Example 5>
In Example 1, 10 parts by mass of gelatinized starch made from urea phosphate esterified starch (trade name: MS#4000/Nippon Shokuhin Kako Co., Ltd.) was used as a modified styrene-butadiene copolymer resin (trade name: Nipol LX430). (Manufactured by Nippon Zeon Co., Ltd.) A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount was changed to 10 parts by mass.

<Comparative example 6>
A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of wheat starch having an average particle diameter of 18 μm was changed from 16.7 parts by mass to 0 part by mass.

<Comparative Example 7>
In Example 1, the amount of wheat starch having an average particle diameter of 18 μm was changed from 16.7 parts by mass to 0 part by mass, and urea phosphate esterified starch (trade name: MS#4000/manufactured by Nippon Shokubai Co., Ltd.) was used as a raw material. A pressure-sensitive adhesive sheet for inkjet recording was obtained in the same manner as in Example 1 except that the amount of the gelatinized starch was changed from 10 parts by mass to 0 part by mass.

[Preparation of samples for physical property evaluation]
The CMYK solid printing for each color was performed with the aqueous pigment ink on the inkjet pressure-bonding paper obtained in each of the examples and comparative examples using an inkjet printer (Truepress Jet520, manufactured by SCREEN). After that, the pressure-sensitive adhesive paper for printing after printing is adjusted to have a water content of 5.5 to 7.0%, and 10 cm×10 cm test pieces are cut and three sheets are stacked, and then the dry sealer MS-9200II (stock The confidential surfaces provided with the pressure-sensitive adhesive coating layer were pressure-bonded to each other by Duplo Co., Ltd.). During pressure bonding, the sealer gap was set so that the peel strength immediately after bonding was about 150 g/25 mm width. The pressure-bonded paper test pieces thus obtained were separated from each other on the pressure-bonded surfaces, and various evaluations were performed in the following manner.

[Evaluation of color development]
The color density of the recorded image on the pressure-bonded surface after peeling was visually evaluated. The highest color density was evaluated as 5 and the lowest color density was evaluated as 1, and 3 or more were evaluated as acceptable.

[Evaluation of transition to facing surface]
After peeling, it was visually evaluated whether or not the recorded image printed on one pressure-bonded surface was transferred to the facing surface (the other pressure-bonded surface). The one with the least transition to the facing surface was 6, and the one with the most transition to the facing surface was 1, and the evaluation was made in 6 levels, and 3 or more was passed.

[Evaluation of dirt on pressure roll]
After the pressure-sensitive adhesive sheet for inkjet recording was pressure-bonded with 10,000 sheets of postcards using a dry sealer MS-9200II, the degree of contamination of the pressure roll of the dry sealer was visually evaluated. The pressure roller with the least stain was rated as 4, and the pressure roller with the most stain was rated as 1 and evaluated in 4 grades, and 3 or more was passed.

[Surface strength]
The presence or absence of white spots in the pressure-sensitive adhesive coating layer was visually determined using a color-developing device described in JIS K 5701 (Ishikawajima Sangyo: RI-II type). The coating layer with the least white voids was 6, and the coating layer with the most white voids was 1, and the grade was evaluated in 6 levels, and 3 or more was passed.

[Evaluation of ink dryness]
Using an inkjet printer (Truepress Jet520, manufactured by SCREEN), solid printing of each color of CMYK with an aqueous pigment ink was continuously printed on 6000 m of pressure-sensitive inkjet recording paper at a printing speed of 128 m/min. The ink stains attached to the pressure-sensitive adhesive paper for inkjet recording after printing are visually observed, and the stains on the paper are evaluated as 6 and the stain on the paper as 1 is evaluated on a scale of 6 to 3 or more. I passed. When the ink drying property is poor, the ink in the solid print portion is transferred to the feed roll of the inkjet printer and the like, and the ink is further transferred to the paper, causing ink stain on the inkjet recording pressure-sensitive paper.

[Blocking of winding roll]
Ink, indigo, crimson, and yellow 10% halftone dot printing was continuously printed on a pressure-sensitive adhesive paper 6000 m for inkjet recording at a printing speed of 200 m/min with a foam printer. The blocking state of the roll-out part at the time of printing was visually observed, and when the roll-out was smooth, it was evaluated as 5, and when the roll-out was unstable, the evaluation was made into 5 levels, and 3 or more was passed. When the feeding of the roll is unstable, the paper will meander and break on the printing machine.

The formulations of the pressure-sensitive adhesive composition paints in Examples and Comparative Examples are shown in FIGS. 1 and 2, and the evaluation results of the physical properties of the ink jet recording pressure-sensitive adhesive sheets in Examples and Comparative Examples are shown in FIG.

As is clear from the results of FIG. 3, the ink jet recording pressure-sensitive adhesive papers obtained in Examples 1 to 25 have color development, print transfer to the opposite surface, pressure roll stain, surface strength, ink dryness, In all of the cases, blocking was 3 grades or more that passed, and there was no problem in actual operation.

On the other hand, the pressure-sensitive adhesive paper for inkjet recording obtained in Comparative Example 1 was unpractical in terms of ink dryness and surface strength. It is considered that this is because the saponification degree of polyvinyl alcohol used as the binder was less than 90 mol %.

The pressure-sensitive adhesive paper for inkjet recording obtained in Comparative Example 2 was unusable for practical use in terms of print transfer to the facing surface and ink drying property. It is considered that this is because the saponification degree of the polyvinyl alcohol used as the binder exceeded 98 mol%.

The pressure-sensitive adhesive sheet for inkjet recording obtained in Comparative Example 3 was not practical for practical use in terms of print transfer to the facing surface and surface strength. This is probably because the gelatinized starch was not added.

The pressure-sensitive adhesive paper for ink jet recording obtained in Comparative Example 4 was not practical for practical use in terms of print transfer to the facing surface, stains on the pressure roll, and ink drying property. It is considered that this is because the absorbability of the ink was inhibited because the binder was only polyvinyl alcohol and the gelatinized starch was not mixed.

The pressure-sensitive adhesive paper for inkjet recording obtained in Comparative Example 5 was unpractical in terms of color developability, print transfer to the facing surface, stains on the pressure roll, and ink drying property. It is considered that this is because the absorbability of the ink was hindered because the styrene-butadiene copolymer resin was used without using the gelatinized starch.

The pressure-sensitive adhesive recording paper for inkjet recording obtained in Comparative Example 6 was not suitable for practical use in terms of blocking evaluation of the take-up roll due to unstable feeding of the paper during printing with a foam printing machine and paper breakage. There was nothing. It is considered that this is because the starch particles were not blended.

1 Crimping paper roll 2 Feeding part 3 Blocking part 4 Feeding position when normal

Claims (13)

Pressure-sensitive adhesive paper for ink jet recording having a pressure-sensitive adhesive coating layer containing a non-peeling pressure-sensitive adhesive base, an inorganic pigment, starch particles, a binder and a water-soluble polyvalent metal salt on at least one surface of the base paper. And
An ink jet recording pressure-sensitive adhesive sheet for use in an ink jet printer using an aqueous pigment ink, which contains an intermediate saponification type polyvinyl alcohol having a saponification degree of 90 to 98 mol% as the binder and gelatinized starch. The pressure-sensitive adhesive sheet for inkjet recording according to claim 1, wherein the binder contains an intermediate saponified polyvinyl alcohol having a saponification degree of 92 to 96 mol %. The pressure-sensitive adhesive sheet for inkjet recording according to claim 1 or 2, wherein the gelatinized starch is a phosphoric acid esterified starch. The pressure-sensitive adhesive sheet for inkjet recording according to claim 1, wherein the content of the non-peeling pressure-sensitive adhesive is in the range of 95 to 170 parts by mass with respect to 100 parts by mass of the inorganic pigment. .. The pressure-sensitive adhesive sheet for inkjet recording according to claim 1, wherein the inorganic pigment contains amorphous silica. The pressure-sensitive adhesive paper for inkjet recording according to claim 1, which contains gel-type silica as the inorganic pigment. The pressure-sensitive adhesive sheet for inkjet recording according to claim 5 , wherein an oil absorption amount of the amorphous silica measured according to ISO 787-5 is in a range of 180 to 400 ml/100 g. The pressure-sensitive adhesive sheet for inkjet recording according to claim 5 or 7, wherein the amorphous silica has an average particle diameter in the range of 1.0 to 15.0 µm measured by a laser diffraction method. A starch particle having an average particle diameter of 10 to 20 μm as measured by a laser diffraction method is contained as the starch particle in a solid content range of 10 to 30% by mass with respect to the inorganic pigment. 8. A pressure-sensitive adhesive sheet for inkjet recording according to any one of 8. The pressure-sensitive adhesive paper for inkjet recording according to claim 1, wherein the content of the gelatinized starch is in the range of 2.5 to 18% by mass in terms of solid content with respect to the inorganic pigment. .. The coating amount of the pressure-sensitive adhesive coating layer on one side of the base paper is 2.0 to 12.0 g/m ² in terms of solid content, 11. Adhesive paper for inkjet recording. The pressure-sensitive adhesive paper for inkjet recording according to any one of claims 1 to 11, which has a basis weight of 60 to 200 g/m ² and is suitable as a postcard paper. A step of preparing a base paper,
Preparing a pressure-sensitive adhesive composition using a pressure-sensitive adhesive composition raw material containing a non-peeling pressure-sensitive adhesive base, an inorganic pigment, starch particles, a binder and a water-soluble polyvalent metal salt,
At least one surface of the base paper, the step of applying the pressure-sensitive adhesive composition to provide a pressure-sensitive adhesive coating layer,
Gel method silica is included as the inorganic pigment,
The binder contains an intermediate saponification type polyvinyl alcohol having a saponification degree of 90 to 98 mol% and a gelatinized starch, and a pressure-sensitive adhesive sheet for inkjet recording used in an inkjet printer using an aqueous pigment ink. Manufacturing method.

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