Post-glue pressure-bonded recording base paper and post-glue pressure-bonded recording paper

Abstract

To provide a base paper for compression recording after applying a paste, which has excellent printability and re-peelability in an after paste applying method.SOLUTION: There is provided a base paper for compression recording after applying a paste, comprising: a substrate paper; and a coating layer laminated on at least one side of the substrate paper, in which the substrate paper contains a paper strength enhancer and a sizing agent, the coating layer contains a pigment and a binder, the coating layer contains light calcium carbonate, kaolin and an organic pigment as a pigment, a content ratio of light calcium carbonate to all pigments in the coating layer is 40 mass% or more and 69 mass% or less, a content ratio of kaolin to all pigments in the coating layer is 30 mass% or more and 50 mass% or less, a content ratio of the organic pigment to all pigments in the coating layer is 1 mass% or more and 10 mass% or less, a mass ratio of kaolin to light calcium carbonate in the coating layer is 0.50 or more and 1.20 or less, and a mass ratio of the organic pigment to light calcium carbonate is 0.03 or more and 0.25 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a post-adhesive pressure-bonding recording base paper and a post-adhesive pressure-bonding recording paper. [Background technology]

[0002] A pressure-bonded recording paper is conventionally known, which is formed by printing various information that needs to be concealed or hidden, folding the paper, and pressing the opposing surface so that it can be peeled off. In addition, as such a pressure-bonded recording paper, there are a pre-gluing method in which a pseudo-adhesive layer is pre-laminated on the surface of a coated paper, various information is printed on the surface of the pseudo-adhesive layer, and the paper is folded so that the pseudo-adhesive layer faces the surface and pressed so that it can be peeled off, and a post-gluing method in which a pseudo-adhesive layer is laminated on the printed surface after printing on the surface of the coated paper, and the pseudo-adhesive layer is further folded so that the pseudo-adhesive layer faces the surface and pressed so that it can be peeled off. In recent years, the post-gluing method, which has an excellent texture of the adhesive surface after peeling and a luxurious feel, has been widely used.

[0003] On the other hand, offset printing is widely used as a method for printing large quantities of coated paper at high speed. Therefore, coated paper is required to have many properties such as ink receptivity, surface strength, and sizing properties that are compatible with offset printing. On the other hand, inkjet printing is widely used as a method for printing individual information on coated paper. Therefore, post-glue pressure-bonding recording paper, which often has common information printed by offset printing and variable information added by inkjet printing, is required to have both offset printability and inkjet printability at the same time.

[0004] In contrast, the above-mentioned post-glue pressure-bonded recording paper is generally made of conventional coated paper for offset printing, and therefore has the disadvantage that the adhesive forming the pseudo-adhesive layer easily penetrates the coating layer, and sufficient pressure-bonding stability cannot be obtained. On the other hand, when a large amount of adhesive is applied to conventional coated paper for offset printing in order to obtain sufficient adhesive strength, the paper is not easily peeled off from the peeling surface when peeled off again, and the coated paper may be torn.

[0005] In view of these circumstances, for example, a coated paper for pressure-bonding sheets has been proposed, which has a coating layer laminated on one side of a base paper, this coating layer contains a pigment, and the calcium carbonate content relative to 100% by mass of the pigment contained in this coating layer is 30% by mass or more and 90% by mass or less (see Patent Document 1). By containing calcium carbonate in the above range in the coating layer, the above coated paper for pressure-bonding sheets can increase ink absorbency in inkjet printing while suppressing to a certain degree the penetration of the adhesive that forms the pseudo-adhesive layer, thereby increasing inkjet printability and adhesion to a certain degree.

[0006] Also, in order to prevent material destruction during re-peeling by suppressing the penetration of the adhesive forming the pseudo-adhesive layer into the base paper, a post-adhesive pressure-bonded recording base paper has been proposed that contains a polyacrylic paper strength enhancer in the base paper and further contains 30 parts by mass or more of kaolin in the coating layer (see Patent Document 2). The above-mentioned post-adhesive pressure-bonded recording base paper can suppress excessive penetration of the adhesive and ensure the strength of the base material, so it can have a certain effect on the re-peeling of the pseudo-adhesive layer.

[0007] Furthermore, a coated paper for pressure-sensitive adhesive sheets that is compatible with the inkjet method and contains 50 parts by mass or more of kaolin and 10 to 50 parts by mass of precipitated calcium carbonate in the coating layer has also been proposed (see Patent Document 3). The above coated paper for pressure-sensitive adhesive sheets also exhibits a white paper gloss value above a certain level, and is therefore expected to exhibit a certain level of inkjet printability as well. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2011-195990 A [Patent Document 2] JP 2016-003404 A [Patent Document 3] JP 2009-228171 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, the coated paper for pressure-bonding sheets of the above-mentioned conventional technology has a certain water absorption due to the inkjet printability described above, so the adhesive forming the pseudo-adhesive layer is impregnated into the coating layer. Therefore, for example, when an ultraviolet-curing glue is used as the adhesive, the adhesive cannot be effectively prevented from penetrating into the coating layer, and there is a risk that a large amount of adhesive is used. Furthermore, as a result of using a large amount of adhesive in this coated paper for pressure-bonding sheets, there is a risk that the coated paper will not be peeled off from the peeling surface when peeled off again, and the coated paper will be destroyed.

[0010] The present invention has been made in light of the above circumstances, and has an object to provide a post-adhesive pressure-bonding recording base paper that can be used to produce a post-adhesive pressure-bonding recording paper that is suitable for inkjet printing and has excellent removability. [Means for solving the problem]

[0011] A post-glue pressure-bonding recording base paper according to one embodiment of the present invention comprises a base paper and a coating layer laminated on at least one side of the base paper, the base paper containing a paper strength agent and a sizing agent, the coating layer containing a pigment and a binder, the coating layer containing light calcium carbonate, kaolin and an organic pigment as the pigments, the content of the light calcium carbonate relative to the total pigments in the coating layer being 40% by mass or more and 69% by mass or less, and the content of the kaolin relative to the total pigments in the coating layer being 30% by mass or more and 50% by mass or less. a content ratio of the organic pigment to the total pigments in the coating layer is 1% by mass or more and 10% by mass or less, a mass ratio of the kaolin to the light calcium carbonate in the coating layer is 0.50 to 1.20, a mass ratio of the organic pigment to the light calcium carbonate is 0.03 to 0.25, a primary particle diameter of the light calcium carbonate is 0.05 μm to 0.50 μm, a peel strength in the Z-axis direction is 700 kPa or more, and a toluene oil absorption is 100 seconds or more. Effect of the Invention

[0012] According to the present invention, it is possible to provide a post-adhesive pressure-bonding recording base paper that is suitable for inkjet printing and has excellent removability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Description of the embodiment of the present invention] A post-glue pressure-bonding recording base paper according to one embodiment of the present invention comprises a base paper and a coating layer laminated on at least one side of the base paper, the base paper containing a paper strength agent and a sizing agent, the coating layer containing a pigment and a binder, the coating layer containing light calcium carbonate, kaolin and an organic pigment as the pigments, the content of the light calcium carbonate relative to the total pigments in the coating layer being 40% by mass or more and 69% by mass or less, and the content of the kaolin relative to the total pigments in the coating layer being 30% by mass or more and 50% by mass or less. a content ratio of the organic pigment to the total pigments in the coating layer is 1% by mass or more and 10% by mass or less, a mass ratio of the kaolin to the light calcium carbonate in the coating layer is 0.50 to 1.20, a mass ratio of the organic pigment to the light calcium carbonate is 0.03 to 0.25, a primary particle diameter of the light calcium carbonate is 0.05 μm to 0.50 μm, a peel strength in the Z-axis direction is 700 kPa or more, and a toluene oil absorption is 100 seconds or more.

[0014] In the post-glue pressure-bonding recording base paper, since the base paper contains a paper strength agent and a sizing agent, the penetration of the adhesive into the coating layer is effectively suppressed, and the breakage of the base paper during re-peeling can be further effectively suppressed. Since the coating layer contains a pigment and a binder, the penetration and fixation of the inkjet ink and offset ink into the coating layer are promoted, and the base paper has suitable inkjet printability and offset printability. In addition, since the content ratio of the light calcium carbonate to the total pigments in the coating layer is 40% by mass or more and 69% by mass or less, the inkjet printability can be improved. Since the content ratio of the kaolin to the total pigments in the coating layer is 30% by mass or more and 50% by mass or less, the penetration of the adhesive forming the pseudo-adhesive layer can be prevented. Since the content ratio of the organic pigment to the total pigments in the coating layer is 1% by mass or more and 10% by mass or less, the inkjet printability can be improved, and the adhesive can be appropriately retained on the surface layer, thereby improving smoothness. The mass ratio of the kaolin to the light calcium carbonate in the coating layer is 0.50 to 1.20, the mass ratio of the organic pigment to the light calcium carbonate is 0.03 to 0.25, and the primary particle size of the light calcium carbonate is 0.05 μm to 0.50 μm, so that the adhesive forming the pseudo-adhesive layer is sufficiently suppressed from penetrating into the coating layer and the ink-jet ink can be absorbed well. Furthermore, the post-glue pressure-bonded recording base paper has a peel strength in the Z-axis direction within the above range, so that the post-glue pressure-bonded recording base paper has sufficient peel strength. Therefore, in the post-glue pressure-bonded recording paper in which the pseudo-adhesive layer is laminated on the surface of the coating layer, when the post-glue pressure-bonded recording paper is folded so that the pseudo-adhesive layer faces each other and then peeled off again, the base paper is prevented from breaking, and the post-glue pressure-bonded recording base paper can be peeled off suitably at the peel surface. In addition, since the toluene oil absorption of the post-glue pressure-bonded recording base paper is within the above range, when an adhesive, for example, an ultraviolet-curable adhesive, is used, the penetration of the adhesive is suitably suppressed. Therefore, it is possible to maintain adhesion while reducing the amount of adhesive used, and to effectively suppress breakage of the base paper when peeled off. Therefore, the post-glue pressure-bonded recording base paper has inkjet printability and can produce a post-glue pressure-bonded recording paper with excellent peelability.

[0015] The organic pigment preferably has a solid shape. The solid shape means a pigment having a specific gravity of 0.80 to 1.20 g / cm. 3 This refers to a high density organic pigment. The dense shape of the organic pigment makes it difficult for the particle shape of the organic pigment to be crushed during calendar processing, so that the smoothness of the post-adhesive pressure-bonding recording base paper does not become too high, and a moderate smoothness can be obtained. Therefore, the ink absorption can be improved and the penetration of the adhesive can be appropriately prevented.

[0016] It is preferable that the light calcium carbonate is an aggregate of primary particles, and the shape of the primary particles is cubic. By making the light calcium carbonate an aggregate of primary particles, and the shape of the primary particles is cubic, the dynamic contact angle of the surface of the post-adhesive pressure-bonding recording base paper can be increased, and the halftone dot reproducibility of the inkjet ink can be improved. Therefore, the ink drying property and print density of the post-adhesive pressure-bonding recording base paper can be improved.

[0017] The cob size of the post-adhesive press-bonded recording base paper is 10 g / m 2 More than 50g / m 2 By having the Cobb sizing degree of the post-gluing pressure-bonding recording base paper in the above range, excessive penetration of the water-based adhesive can be prevented, particularly in the case of a post-gluing method using a water-based adhesive, and removability can be facilitated. Also, the base paper can be made less susceptible to the effects of humidity changes.

[0018] The post-adhesive pressure-bonded recording base paper preferably further comprises an under-coating layer, and the coating layer is laminated on the surface of the under-coating layer. By providing the under-coating layer, the post-adhesive pressure-bonded recording base paper can promote the flatness of the coating layer surface when the coating layer is laminated, the high definition of printed information, and the improvement of the quality of full-color printing, and can also suppress the coating liquid used in the pseudo-adhesive layer (described later) of the post-adhesive pressure-bonded recording paper laminated on the outermost surface of the coating layer from penetrating into the base paper, thereby reducing the amount of coating liquid used.

[0019] The post-adhesive pressure-bonded recording paper according to one embodiment of the present invention uses the post-adhesive pressure-bonded recording base paper. By using the post-adhesive pressure-bonded recording base paper, the post-adhesive pressure-bonded recording paper can be manufactured to have inkjet printability and excellent removability.

[0020] In the present invention, the "peel strength in the Z-axis direction" refers to the peel strength in the thickness direction according to ISO 15754. The "toluene oil absorption" refers to a value according to JIS-P-8130 (1994). The "Cobb sizing degree" refers to a value measured for 10 seconds according to JIS-P8140 (1998).

[0021] [Details of the embodiment of the present invention] The present invention will be described in detail below. The following description of the components may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments.

[0022] <Post-glue pressure-bonded recording base paper> The post-adhesive compression recording base paper includes a base paper and a plurality of coating layers laminated on at least one surface of the base paper. The post-adhesive compression recording base paper preferably further includes an under-coating layer, and the coating layer is laminated on a surface of the under-coating layer.

[0023] [Base paper] The base paper is mainly composed of raw pulp. The base paper may be a single layer or multiple layers. The base paper contains a paper strength agent and a sizing agent. Since the base paper contains a paper strength agent and a sizing agent, the penetration of the adhesive into the coating layer is effectively suppressed, and the breakage of the base paper during re-peeling can be further effectively suppressed.

[0024] (Raw pulp) As the raw material pulp, known pulp can be used, and virgin pulp, recycled paper pulp, or a combination thereof can be appropriately used. Examples of virgin pulp that can be used include chemical pulps such as bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), unbleached softwood kraft pulp (NUKP), semi-bleached hardwood kraft pulp (LSBKP), semi-bleached softwood kraft pulp (NSBKP), hardwood sulfite pulp, and softwood sulfite pulp; mechanical pulps such as stone ground pulp (SGP), pressed stone ground pulp (TGP), chemi-ground pulp (CGP), groundwood pulp (GP), and thermomechanical pulp (TMP); and pulps produced chemically or mechanically from non-wood fibers such as kenaf, hemp, and reed.

[0025] Examples of waste paper pulp include disintegrated waste paper pulp, disintegrated and deinked waste paper pulp (DIP), and disintegrated, deinked and bleached waste paper pulp, which are produced from brown waste paper, kraft envelope paper, magazine paper, newspaper paper, flyer paper, office paper, corrugated cardboard paper, white waste paper, Kent waste paper, imitation waste paper, and land certificate paper.

[0026] Among these, the pulp fiber is preferably a combination of hardwood kraft pulp (LKP) and softwood kraft pulp (NKP), and more preferably a combination of hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP). By using these two types of pulp, the post-glue pressure-bonding recording base paper can accurately adjust the water absorption of the base paper and can have excellent printability and processability for form printing, etc.

[0027] In the case where hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) are used in combination as the pulp fibers, the lower limit of the content of hardwood kraft pulp (LKP) relative to the total pulp components is preferably 65% ​​by mass, more preferably 70% by mass, and even more preferably 75% by mass. On the other hand, the upper limit of the content of hardwood kraft pulp (LKP) relative to the total pulp components is preferably 98% by mass, more preferably 96% by mass, and even more preferably 95% by mass. In the case where hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) are used in combination as the pulp fibers, the lower limit of the content of softwood kraft pulp (NKP) relative to the total pulp components is preferably 2% by mass, more preferably 4% by mass, and even more preferably 5% by mass. On the other hand, the upper limit of the content of softwood kraft pulp (NKP) relative to 100% by mass of the total pulp components is preferably 35% by mass, more preferably 30% by mass, and even more preferably 25% by mass. Since hardwood kraft pulp (LKP) has a short fiber length, the gap between the fibers of the obtained base paper can be relatively small. In contrast, since softwood kraft pulp (NKP) has a long fiber length, the bond between the fibers of the obtained base paper can be strengthened. Therefore, the base paper contains hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) in the above ratio, and while improving the strength of the base paper, the base paper has a moderate water absorption property to improve ink transferability, and the binder forming the coating layer can be inserted between the fibers of the base paper and the binder and the fibers can be tightly bonded. Therefore, the anchor effect of the coating layer of the post-glue pressure-bonded recording base paper is high, and in the post-glue pressure-bonded recording paper in which a pseudo-adhesive layer is laminated on the surface of the coating layer, cracking of the coating layer can be suitably prevented when the pseudo-adhesive layer is folded to face each other and bonded and then peeled off again.

[0028] The lower limit of the freeness of the hardwood kraft pulp (LKP) is preferably 360 ml, more preferably 400 ml, and even more preferably 420 ml. The upper limit of the freeness of the hardwood kraft pulp (LKP) is preferably 495 ml, more preferably 490 ml, and even more preferably 480 ml. On the other hand, the lower limit of the freeness of the softwood kraft pulp (NKP) is preferably 500 ml, more preferably 505 ml, and even more preferably 510 ml. The upper limit of the freeness of the softwood kraft pulp (NKP) is preferably 610 ml, more preferably 600 ml, and even more preferably 590 ml. By setting the freeness of the hardwood kraft pulp (LKP) and the softwood kraft pulp (NKP) within the above ranges, the interlaminar strength in the Z-axis direction of the base paper, the water absorption, and the adhesive permeability can be suitably adjusted, while the tensile strength, tear strength, etc. of the base paper can be increased. "Freeness" is a value measured in accordance with JIS-P-8121 (2012).

[0029] (Paper strength agent) Examples of the paper strength enhancer contained in the base paper include polyvinyl alcohol polymers, polyacrylamide polymers, cationic starch, urea / formalin resins, and melamine / formalin resins. Among these, it is preferable to add a polyacrylamide-based paper strength enhancer. The post-glue pressure-bonding recording base paper can suppress the penetration of adhesive into the base paper by containing a polyacrylamide-based paper strength enhancer in the base paper. In addition, since this polyacrylamide-based paper strength enhancer has high compatibility with the ultraviolet-curable adhesive used as the adhesive, even if the ultraviolet-curable adhesive penetrates into the base paper, the ultraviolet-curable adhesive seals the inside of the base paper, suppressing the decrease in the strength of the base paper, and the peel strength in the Z-axis direction (thickness direction) can be suitably increased.

[0030] The amount of the paper strength agent added is preferably 0.5 kg / t or more and 5.0 kg / t or less in terms of solid content. By keeping the content of the paper strength agent in the base paper within the above range, the amount of ink impregnated into the base paper during printing can be appropriately adjusted. In addition, the strength of the base paper can be improved. Here, solid content refers to components other than the solvent. Note that "kg / t" indicates the mass (kg) per ton of pulp.

[0031] (Sizing agent) Examples of sizing agents include alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), neutral rosin sizing agents, rosin sizing agents, styrene-based sizing agents, etc. In particular, AKD is preferred from the viewpoint of obtaining sizing properties with a small addition amount.

[0032] The amount of sizing agent added is preferably 0.1 kg / t or more and 3.0 kg / t or less in terms of solid content. By making the content of the sizing agent in the base paper within the above range, the amount of ink impregnated into the base paper during printing can be appropriately adjusted. In addition, the fixation of the sizing agent to the raw pulp and the strength of the base paper can be improved.

[0033] (Other additives) In addition to the pulp, paper strength agent, and sizing agent, other additives may be used as components of the base paper, if necessary. Examples of other additives that may be used include fillers, coagulants, flocculants, defoamers, fluorescent whitening agents, aluminum sulfate, retention aids, drainage aids, wet strength agents, coloring dyes, dye fixing agents, coloring pigments, and water resistance agents. These additives may be used alone or in combination.

[0034] [Coating layer] The coating layer is laminated on at least one side of the base paper. The coating layer contains a pigment and a binder. Since the coating layer contains a pigment and a binder, the penetration of inkjet ink or offset ink into the coating layer is promoted and the ink is fixed therein, and the coating layer has suitable suitability for inkjet printing and offset printing.

[0035] Pigments The coating layer contains light calcium carbonate, kaolin, and an organic pigment as the pigment. The coating layer contains light calcium carbonate, kaolin, and an organic pigment as the pigment. Because the coating layer contains light calcium carbonate, kaolin, and an organic pigment as the pigment, penetration of the adhesive into the coating layer is effectively suppressed, and tearing of the base paper during re-peeling can be further effectively suppressed.

[0036] By including precipitated calcium carbonate in the coating layer, the ink drying properties are excellent, and bleeding and unevenness in printing are suppressed, resulting in good print quality.

[0037] The lower limit of the primary particle diameter of the light calcium carbonate is 0.05 μm, preferably 0.06. On the other hand, the upper limit of the primary particle diameter of the light calcium carbonate is 0.50 μm, preferably 0.30, more preferably 0.20. When the primary particle diameter of the light calcium carbonate is within the above range, the penetration of the adhesive forming the pseudo-adhesive layer into the coating layer can be sufficiently suppressed, and the ink-jet ink can be absorbed well. The primary particle diameter of the light calcium carbonate is a measured value obtained by observation with an electron microscope (SEM photograph: 10,000 times magnification). The particle diameter can also be measured using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Microtrack Bell, product name: MT3300).

[0038] It is preferable that the light calcium carbonate is an aggregate of primary particles, and the shape of the primary particles is cubic. By making the light calcium carbonate an aggregate of primary particles, and the shape of the primary particles is cubic, the dynamic contact angle of the surface of the post-adhesive pressure-bonding recording base paper can be increased, so that the halftone dot reproducibility of the ink is improved and the degree of penetration is appropriate. Therefore, the ink drying property and print density of the post-adhesive pressure-bonding recording base paper can be improved.

[0039] The lower limit of the content of the light calcium carbonate relative to the total pigments in the coating layer is 40% by mass, and preferably 45% by mass. Meanwhile, the upper limit of the content of the light calcium carbonate relative to the total pigments is 69% by mass, and preferably 65% ​​by mass. If the content of the light calcium carbonate relative to the total pigments is less than the lower limit, the drying properties of the ink may be reduced. On the other hand, if the content of the light calcium carbonate relative to the total pigments exceeds the upper limit, the absorbency of the inkjet ink may be reduced, resulting in low print density.

[0040] Kaolin is relatively inexpensive, and the inclusion of kaolin in the coating layer provides excellent suitability for high-speed coating with a blade coater, a film transfer roll, etc., as well as excellent post-sizing suitability. Examples of kaolin include delaminated kaolin and calcined kaolin.

[0041] The lower limit of the content of the kaolin relative to the total pigments in the coating layer is 30% by mass, preferably 35% by mass. Meanwhile, the upper limit of the content of the kaolin relative to the total pigments is 50% by mass, preferably 48% by mass. When the content of the kaolin relative to the total pigments is less than the lower limit, the ink drying property is improved, but the print density tends to decrease. On the other hand, when the content of the kaolin relative to the total pigments exceeds the upper limit, the print density is improved, but the ink drying property may decrease.

[0042] Examples of the organic pigment include plastic pigments such as polypropylene, polyethylene, polystyrene, styrene-butadiene copolymers, acrylic resins, styrene-acrylic copolymers, microcapsules, urea resins, melamine resins, etc. These can be used alone or in combination of two or more kinds.

[0043] The organic pigment preferably has a solid shape. Here, the density of the solid organic pigment is 0.80 g / cm 3 More than 1.10g / cm 3It is preferable that the organic pigment has a dense shape, so that the particle shape of the organic pigment is not easily crushed during calendar processing, and therefore the smoothness of the post-adhesive pressure-bonding recording base paper does not become too high, and a moderate smoothness can be obtained. Therefore, the apparent glossiness and excessive penetration of the (pseudo) adhesive can be suppressed, and removability can be improved.

[0044] The lower limit of the content of the organic pigment relative to the total pigment in the coating layer is 1% by mass, and preferably 2% by mass. Meanwhile, the upper limit of the content of the organic pigment relative to the total pigment is 10% by mass, and preferably 7% by mass. If the content of the organic pigment relative to the total pigment is less than the lower limit, the print density may decrease. Meanwhile, if the content of the organic pigment relative to the total pigment exceeds the upper limit, the ink-jet ink absorbency may deteriorate.

[0045] The lower limit of the mass ratio of the kaolin to the light calcium carbonate in the coating layer is 0.50, preferably 0.60. Meanwhile, the upper limit of the mass ratio of the kaolin to the light calcium carbonate is 1.20, preferably 1.10. If the mass ratio of the kaolin to the light calcium carbonate is less than the lower limit, the penetration of the adhesive forming the pseudo-adhesive layer into the coating layer may not be sufficiently suppressed. Meanwhile, if the mass ratio of the kaolin to the light calcium carbonate exceeds the upper limit, the absorbency of the ink-jet ink may be deteriorated.

[0046] The lower limit of the mass ratio of the organic pigment to the light calcium carbonate is 0.03, and more preferably 0.05. Meanwhile, the upper limit of the mass ratio of the organic pigment to the light calcium carbonate is 0.25, and preferably 0.23. If the mass ratio of the organic pigment to the light calcium carbonate is less than the lower limit, the penetration of the adhesive forming the pseudo-adhesive layer into the coating layer may not be sufficiently suppressed. Meanwhile, if the mass ratio of the organic pigment to the light calcium carbonate exceeds the upper limit, the absorbency of the inkjet ink may be deteriorated.

[0047] The coating layer may contain other pigments other than light calcium carbonate, kaolin, and organic pigments. The other pigments are not particularly limited, and examples thereof include white inorganic pigments such as heavy calcium carbonate, magnesium carbonate, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, synthetic amorphous silica, colloidal silica, kaolin-modified colloidal silica, aluminum hydroxide, alumina, alumina hydrate, lithopone, zeolite, hydrated halloysite, and magnesium hydroxide, which may be used alone or in combination of two or more. The content of the other pigments is preferably 10 parts by mass or less.

[0048] "binder" The binder for the coating layer is not particularly limited, and examples thereof include starch derivatives such as cationic starch, etherified starch, phosphated starch, hydroxyethyl etherified starch, and carbamic acid esterified starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soybean protein, polyvinyl alcohol or a derivative thereof; conjugated diene copolymer latexes such as polyvinylpyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, and methyl methacrylate-butadiene copolymer; acrylic polymer latexes such as polymers or copolymers of acrylic acid esters and methacrylic acid esters; vinyl polymer latexes such as ethylene-vinyl acetate copolymers; and cationic groups are used in these various polymers to form cationic polymers. Examples of the latex include ionized latex, latex with the polymer surface cationized by a cationic surfactant, latex polymerized under cationic polyvinyl alcohol and the cationic vinyl alcohol distributed on the polymer surface, and latex polymerized in a suspension dispersion of cationic colloidal particles and the cationic colloidal particles distributed on the polymer surface; water-based adhesives such as thermosetting synthetic resins such as melamine resins and urea resins; polymers or copolymers of acrylic acid esters and methacrylic acid esters such as polymethyl methacrylate; synthetic resin adhesives such as polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and alkyd resins, and these can be used alone or in combination of two or more. Among these, from the viewpoint of cost-effectiveness, a combination of a highly versatile styrene-butadiene copolymer latex and a starch derivative (SBR) is preferably used. In addition, the glass transition temperature of the styrene-butadiene copolymer is preferably low so that it can have excellent flexibility, and can be, for example, less than 0°C.

[0049] The lower limit of the mass ratio (solid content equivalent) of the binder to the pigment in the coating layer is preferably 5% by mass, more preferably 6% by mass. On the other hand, the upper limit of the mass ratio (solid content equivalent) of the binder to the pigment is preferably 20% by mass, more preferably 15% by mass. If the mass ratio of the binder to the pigment is less than the lower limit, the strength of the coating layer may not be sufficient. On the other hand, if the mass ratio of the binder to the pigment exceeds the upper limit, the adhesion in the coating layer may increase, and blocking, sticking, etc. may occur during the manufacturing process. On the other hand, if the mass ratio of the binder to the pigment is within the above range, the physical properties such as the strength and adhesion of the coating layer can be suitably adjusted.

[0050] In the post-adhesive pressure-bonded recording base paper, multiple coating layers may be laminated. That is, the post-adhesive pressure-bonded recording base paper may have one or multiple coating layers laminated. In this way, when multiple coating layers are laminated, it is preferable that all coating layers contain a pigment and a binder, but as long as at least the outermost coating layer contains the pigment and binder, the other coating layers do not necessarily need to contain the pigment and binder. An example of a coating layer that does not contain the pigment and binder is a clear coating layer made of a water-soluble adhesive.

[0051] In addition to the pigment and binder, the coating layer (coating liquid) may contain, as necessary, conventional additives such as pigment dispersants, thickeners, flow improvers, defoamers, foam inhibitors, lubricants, release agents, foaming agents, penetrating agents, coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, water-resistant agents, dyes, and fixing agents, as well as auxiliaries such as stearic acid, calcium stearate, oleic acid, calcium oleate, ammonium oleate, lecithin, polyethylene, wax, and derivatives thereof.

[0052] The lower limit of the coating amount (solid content equivalent) of the coating layer is 15.0 g / m 2On the other hand, the upper limit of the coating amount (solid content equivalent) of the coating layer is 35.0 g / m from the viewpoint of improving the UV-based adhesive suitability. 2 is preferred, and 30.0 g / m 2 is more preferable. If the coating weight of the coating layer is less than the lower limit, sufficient printability may not be obtained. On the other hand, if the coating weight of the coating layer exceeds the upper limit, the flexibility may decrease due to hardening of the coating layer, and the processability of the post-glue pressure-bonding recording base paper may decrease. Note that "UV-based glue" refers to glue that hardens by inducing a photopolymerization reaction when irradiated with ultraviolet light.

[0053] (Undercoating layer) The post-adhesive pressure-bonded recording base paper preferably further comprises an under-coating layer under the coating layer. That is, the coating layer is laminated on the surface of the under-coating layer. By providing the under-coating layer, the post-adhesive pressure-bonded recording base paper can promote the flatness of the coating layer surface when the coating layer is laminated, the high definition of the printed information, and the improvement of the quality of full-color printing, and can also suppress the coating liquid used in the pseudo-adhesive layer (described later) of the post-adhesive pressure-bonded recording paper laminated on the outermost surface of the coating layer from impregnating into the base paper, thereby reducing the amount of coating liquid used. The under-coating layer contains a pigment and a binder. Since the under-coating layer contains a pigment and a binder, the penetration and fixation of the inkjet ink or offset ink into the coating layer is promoted, and the paper has suitable inkjet printing suitability and offset printing suitability.

[0054] Pigments The undercoating layer can be provided by applying a coating liquid in which a pigment is dispersed in a binder by a film transfer method. Examples of pigments contained in the undercoating layer include kaolin, talc, calcium carbonate, etc. Among these, calcium carbonate is preferred, and heavy calcium carbonate is particularly preferred. By using heavy calcium carbonate as the pigment contained in the undercoating layer, the post-glue pressure-bonding recording base paper can suitably improve the interlayer strength between the base paper and the coating layer.

[0055] "binder" Examples of the binder contained in the undercoating layer include the above-mentioned starch derivatives, latexes, etc. Among these, starch derivatives are preferred because they are inexpensive and provide an anchoring effect for the base paper, and a combination of a starch derivative and a styrene-butadiene copolymer latex (SBR) is particularly preferred.

[0056] The lower limit of the mass ratio (solid content equivalent) of the binder to the pigment in the undercoating layer is preferably 5% by mass, more preferably 6% by mass. On the other hand, the upper limit of the mass ratio (solid content equivalent) of the binder to the pigment is preferably 18% by mass, more preferably 15% by mass. If the mass ratio of the binder to the pigment is less than the lower limit, the strength of the undercoating layer may not be sufficient. On the other hand, if the mass ratio of the binder to the pigment exceeds the upper limit, the adhesion in the undercoating layer increases, and blocking, sticking, etc. may occur during the manufacturing process. On the other hand, if the mass ratio of the binder to the pigment is within the above range, the physical properties such as strength and adhesion of the undercoating layer can be suitably adjusted.

[0057] The lower limit of the coating amount (solid content equivalent) of the undercoating layer is 5.0 g / m 2 is preferred, and 8.0 g / m 2 On the other hand, the upper limit of the coating amount (solid content equivalent) of the undercoating layer is 18.0 g / m 2 is preferred, and 15.0 g / m 2 If the coating weight of the under-coating layer is less than the lower limit, the unevenness of the base paper surface cannot be sufficiently filled, and the glossiness may decrease when a pseudo-adhesive layer is laminated on the surface of the coating layer. On the other hand, if the coating weight of the under-coating layer is more than the upper limit, the productivity may decrease.

[0058] When coating layers are laminated on both sides of the base paper, the components, coating amount, etc. of each coating layer may be as described above.

[0059] [Physical properties of post-glue pressure-bonded recording base paper] (Basic weight) "Basis weight" is a value measured in accordance with JIS-P-8124 (2011). The basis weight of the post-glue pressure-bonding recording base paper is 80.0 g / m 2 More than 160.0g / m 2 The following is preferred:

[0060] (Z-axis peel strength) The lower limit of the peel strength in the Z-axis direction of the post-glue pressure-bonding recording base paper is 700 kPa, and more preferably 900 kPa. If the peel strength in the Z-axis direction is less than the lower limit, sufficient interlayer strength cannot be obtained, and the base paper may break during re-peeling.

[0061] The lower limit of the toluene oil absorption of the post-glue pressure-bonded recording base paper is 100 seconds, preferably 150 seconds. If the toluene oil absorption is less than the lower limit, the ultraviolet-curable glue forming the pseudo-adhesive may be excessively impregnated, and the adhesiveness of the pseudo-adhesive layer may decrease. If the toluene oil absorption of the post-glue pressure-bonded recording base paper is in the above range, the penetration of the adhesive, for example, when an ultraviolet-curable glue is used as the adhesive, is suitably suppressed. Therefore, the post-glue pressure-bonded recording base paper can reduce the amount of adhesive used and maintain adhesiveness, and can effectively suppress the base paper from breaking when peeled off again. In this embodiment, the toluene oil absorbency is for optimizing the permeability of the solvent contained in the non-aqueous ink and the retention of the pigment contained in the non-aqueous ink in the coating layer. By adjusting the toluene oil absorbency to 100 seconds or more, the pigment contained in the non-aqueous ink can be retained in the coating layer and on its surface due to the synergistic effect of the lipophilicity of the solvent contained in the non-aqueous ink and the flattening treatment of the coating layer. The toluene oil absorbency can be adjusted by the content of kaolin in the coating layer.

[0062] [Manufacturing method of post-glue pressure-bonded recording base paper] The method for producing the post-adhesive pressure-bonded recording base paper is not particularly limited, and may include, for example, a process of making a base paper by making a raw pulp slurry and subjecting it to a press part and a pre-drier part, a process of applying an under-coating liquid in an undercoater part, and then drying and flattening the under-coating layer, and a process of applying a coating liquid and performing a calendaring process. Note that, when the post-adhesive pressure-bonded recording base paper does not have an under-coating layer, instead of the undercoater part, a surface treatment may be performed on the surface of the base paper, followed by drying and flattening.

[0063] Examples of coating devices used when applying the coating liquid or the under-coating liquid include a size press, a blade metering size press, a rod metering size press, a blade coater, a bar coater, a gate roll coater, a rod coater, and an air knife coater.

[0064] As a calendering device for the calendering process, various calenders such as a super calender, a gross calender, a soft compact calender, etc., which are a combination of a metal or drum and an elastic roll, are suitably used in on-machine or off-machine specifications.

[0065] The post-adhesive pressure-bonding recording base paper may be coated with the undercoating liquid or the coating liquid multiple times.

[0066] [Post-glue pressure-bonded recording paper] The post-adhesive pressure-bonding recording base paper is preferably used as a post-adhesive pressure-bonding recording paper in which a coating layer is laminated on one or both sides of a base paper, and a pseudo-adhesive layer is laminated on the surface of the coating layer. The adhesive that forms the pseudo-adhesive layer is not particularly limited, but an ultraviolet-curing adhesive composition in which an ultraviolet-curing component, an acrylic polymer, a photopolymerization initiator, etc. are compatible is preferably used.

[0067] The lower limit of the coating amount (solid content equivalent) of the pseudo adhesive layer is 1 g / m 2 is preferred, and 2 g / m 2 More preferably, 4 g / m 2On the other hand, the upper limit of the coating amount (solid content equivalent) of the pseudo adhesive layer is 15 g / m 2 is preferred, and 13 g / m 2 More preferably, 10 g / m 2 If the coating amount of the pseudo-adhesive layer is less than the lower limit, sufficient adhesion may not be obtained. On the other hand, if the coating amount of the pseudo-adhesive layer is more than the upper limit, the post-adhesive pressure-bonded recording base paper may be destroyed when peeled off again.

[0068] The lower limit of the cob size of the post-glue pressure-bonded recording base paper is 8 g / m 2 More than 10 g / m is preferred. 2 sec is more preferred, 15 g / m 2 On the other hand, the upper limit of the Cobb sizing degree of the post-glue pressure-bonding recording base paper is 60 g / m 2 Less than 50 g / m is preferable. 2 sec is more preferred, 30 g / m 2 More preferably, the cob size is 10 g / m 2 More than 50g / m 2 When the Cobb sizing degree of the post-gluing pressure-bonding recording base paper is 8 g / m or less, excessive penetration of the water-based adhesive is prevented, particularly in the case of a post-gluing method using a water-based adhesive, and removability is facilitated. In addition, the base paper is less susceptible to the effects of humidity changes. 2 In the following cases, the water-based adhesive may penetrate too much, resulting in a decrease in adhesiveness. 2 In the above cases, the water-based adhesive is likely to have uneven adhesion and to overflow from the edge. The Cobb sizing degree in the present invention is a value measured by contacting the surface of the base paper with water for 10 seconds in accordance with JIS-P8140 (1998). The Cobb sizing degree can be adjusted by the content of the paper strength agent and sizing agent in the base paper.

[0069] The lower limit of the Beck smoothness of the post-adhesive pressure-bonded recording base paper is preferably 250 seconds, more preferably 300 seconds. On the other hand, the upper limit of the Beck smoothness is preferably 600 seconds, more preferably 500 seconds. If the Beck smoothness of the post-adhesive pressure-bonded recording base paper is less than the lower limit, the gloss difference between the inkjet printed area and the blank area becomes large. In addition, the print density is also difficult to increase. Conversely, if the Beck smoothness of the post-adhesive pressure-bonded recording base paper exceeds the upper limit, the surface of the outermost coating layer becomes dense, the adhesive is difficult to penetrate, and drying properties may deteriorate. The Beck smoothness is a value based on "Paper and cardboard - Smoothness test method using a Beck smoothness tester" described in JIS-P8119 (1998).

[0070] [Manufacturing method of post-glue pressure-bonded recording paper] A method for manufacturing a post-adhesive pressure-bonded recording paper in which a pseudo-adhesive layer is laminated on the surface of the coating layer of the post-adhesive pressure-bonded recording base paper includes, for example, a method in which offset printing and inkjet printing are performed on the surface side of the coating layer, and then an ultraviolet-curable adhesive composition is applied and cured.

[0071] Examples of the coating device for coating the ultraviolet-curable paste composition include a roll coater, a flexo coater, a gravure coater, an air knife coater, etc. In addition, the method for curing the ultraviolet-curable paste composition may include, for example, using an ultraviolet irradiation device such as a chemical lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, or a metal halide lamp, with an irradiation intensity of 80 W / cm or more and 280 W / cm or less, and an accumulated light amount of 15 mJ / cm. 2 More than 400mJ / cm 2 One example is a method of irradiating and drying the film so that the film becomes as follows (measured using a UVIMAP UM-365HS manufactured by Rigaku Innovative Technologies Inc.).

[0072] Furthermore, the method of folding and pressing the pseudo adhesive layers so that they face each other may be, for example, a method of pressing the pseudo adhesive layers at 10 kg / cm while heating as necessary. 2 More than 3000kg / cm 2The peel strength obtained by this method is, for example, from 40 g / 15 mm to 300 g / 15 mm.

[0073] <Other embodiments> The present invention is not limited to the above-described embodiment, and can be embodied in various other forms in addition to the above-described forms with various modifications and improvements. EXAMPLES

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0075] [Example 1] (Base paper) The base paper was made by making paper using a pulp slurry consisting of 80% by mass of hardwood bleached kraft pulp (LBKP) with a freeness of 380 ml and 20% by mass of softwood bleached kraft pulp (NBKP) with a freeness of 550 ml, to which 4.0 kg / t of a paper strength agent ("DS4326" manufactured by Seiko PMC) and 1.0 kg / t of an internal sizing agent ("FK34 Kai" manufactured by Toho Chemical Industry Co., Ltd.) were added.

[0076] (Undercoating layer) Next, an undercoating liquid containing 100 parts by mass of wet-processed heavy calcium carbonate with a primary particle size of 1.0 μm, 8.0 parts by mass of "RC#20" manufactured by Nippon Shokuhin Co., Ltd., which is a starch derivative as a binder, and 6.0 parts by mass of "PB2901" manufactured by JSR Corporation, which is an SBR latex, was applied to both sides of the base paper in a total amount of 12.0 g / m. 2 (solid content equivalent) to form an undercoating layer.

[0077] (Coating layer) The surface of the undercoat layer was coated with a coating liquid consisting of 37 parts by mass of kaolin with an average particle size of 2.3 μm, 60 parts by mass of aggregated light calcium carbonate (Shiraishi Kogyo Co., Ltd.'s "Hakuenka PZ") with an average primary particle size of 0.08 μm, 3 parts by mass of a dense styrene butadiene plastic pigment (Nippon Zeon Co., Ltd.'s "V1004") as an organic pigment, 2.5 parts by mass of a starch derivative (Nihon Shokuhin Co., Ltd.'s "RC#20") as a binder, and 7.5 parts by mass of an SBR latex (JSR Corporation's "PB2901") at a rate of 22.0 g / m on both sides. 2 (solid content equivalent) and coated with a basis weight of 121.0 g / m 2 After that, a pressure-bonded recording base paper was obtained.

[0078] The amounts of chemicals added were calculated as solids based on the bone dry pulp amount. The coating amounts of the undercoating layer and the coating layer on one side were approximately half the coating amounts on both sides.

[0079] [Examples 2 to 9 and Comparative Examples 1 to 7] The contents of the paper strength agent and sizing agent in the base paper, the binder and pigment type content ratios in the undercoating layer and coating layer, and the coating amount are shown in Tables 1 and 2. The basis weight of the post-adhesive pressure-bonded recording base paper is shown in Table 3, and post-adhesive pressure-bonded recording base papers of Examples 2 to 9 and Comparative Examples 1 to 7 are obtained. As the light calcium carbonate in the coating layer of Comparative Example 4, light calcium carbonate having a primary particle diameter of 1.5 μm and a cubic shape (Shiraishi Kogyo Co., Ltd.'s "Brilliant 15") was used. For the coating layer of Comparative Example 7, heavy calcium carbonate having a primary particle diameter of 0.9 μm and an irregular shape was used. For the organic pigment in the coating layer of Example 9, a hollow acrylic plastic pigment (JSR Corporation's "AE852") was used.

[0080] [Post-glue pressure-bonding recording paper of Examples 1 to 9 and Comparative Examples 1 to 7] Using the post-adhesive pressure-bonding recording base papers of Examples 1 to 9 and Comparative Examples 1 to 7, post-adhesive pressure-bonding recording papers were prepared in the following manner. A UV-curable paste composition or a water-based paste composition was applied to the surface of the coating layer of the post-adhesive pressure-bonding recording base paper in an amount of 10.0 g / m 2Coated in terms of solid content, and after ultraviolet curing or hot air drying with a high-pressure mercury lamp to laminate the pseudo-adhesive layer, the post-adhesive pressure-sensitive recording paper was bent so that the pseudo-adhesive layers faced each other.

[0081] The configurations of the post-adhesive pressure-sensitive recording papers of Examples 1 to 9 and Comparative Examples 1 to 7 are shown in Tables 1 and 2 below.

[0082]

Table 1

[0083]

Table 2

[0084] [Evaluation] The obtained base paper for post-adhesive pressure-sensitive recording or post-adhesive pressure-sensitive recording paper was evaluated by the following method.

[0085] <Grammage> The grammage (g / m 2 ) was measured in accordance with JIS-P-8124 (2011) "Paper and Paperboard - Method for Measuring Grammage".

[0086] <Peeling Strength in the Z-Axis Direction> The peeling strength in the Z-axis direction (kPa) was measured in accordance with TAPPI T 541 using a "L&W ZDTENSILE TESTER" manufactured by Lorentzen & Wettre.

[0087] <Bekk Smoothness> The Bekk smoothness was measured in accordance with the "Method for Testing Smoothness of Paper and Paperboard by Bekk Smoothness Tester" described in JIS-P8119 (1998).

[0088] <Cobb Size Degree> Regarding the base papers for post-adhesive pressure-sensitive recording of Examples 1 to 9 and Comparative Examples 1 to 7, water was brought into contact with the surface of the base paper for 10 seconds in accordance with JIS-P8140 (1998) to measure the Cobb size degree (g / m 2 )

[0089] <Toluene oil absorption> The toluene oil absorption (seconds) was measured in accordance with JIS-P-8130 (1994) "Oil Absorption Test Method" using toluene (manufactured by Yoneyama Chemical Industry Co., Ltd.) as the test oil.

[0090] <Ink drying speed> The ink drying property of the post-adhesive pressure-bonding recording base paper was evaluated by the following procedure. First, ruled lines were printed on the post-adhesive pressure-bonding recording base paper with pigment ink. Then, immediately after printing, the ruled lines were wiped off with a cloth, and the drying property was evaluated according to the following criteria. A printer / PX-404A (manufactured by Seiko Epson Corporation) was used for printing. The printing mode was "Super fine paper, standard." The ink drying property was judged according to the following criteria. It is considered that as the ink drying property rating decreases, roll contamination during actual printing becomes more noticeable. (Evaluation Criteria) ◎: There was almost no dirt on the lines. ◯: Stains were observed on the printed portion. However, the stains were not noticeable and the product was still usable. △: The printed portion was dirty, making it somewhat difficult to use in practice. ×: The printed portion was very dirty and had no practical use.

[0091] <Print density> The print density of the post-glue pressure-bonding recording base paper was evaluated by the following procedure. A print pattern (K100%) was printed on the surface, and the print density of the area printed with pigment ink after 24 hours was measured using a handy fluorescent spectrodensitometer ("FD-7" manufactured by Konica Minolta, Inc.) and judged according to the following criteria. A printer / PX-045A (manufactured by Seiko Epson Corporation) was used for printing. The printing mode was "Super fine paper, standard." The print density was then judged according to the following criteria. (Evaluation Criteria) ⊚: Print density is 1.7 or more. ◯: Print density is 1.5 or more and less than 1.7. △: Print density is 1.3 or more and less than 1.5. ×: The print density is less than 1.3.

[0092] <Removable by post-glue method> The removability of the UV-based adhesive and the water-based adhesive of the post-adhesive pressure-bonded recording paper was evaluated by the following procedure. The removability was evaluated according to the following criteria. (Evaluation Criteria) ⊚: Completely bonded, and the bonded area does not peel off even when bent. ◯: Almost completely bonded, and no peeling or lifting occurred on the bonded surface even when the sample was bent. △: The adhesive adheres to some extent, but is weak and may peel off when bent. x: Weak adhesion or no adhesion at all.

[0093] <Prevention of base paper tearing when post-glue pressure-bonded recording paper is peeled off again> The ability to inhibit the base paper from tearing when the post-glue pressure-bonded recording paper was peeled off again was evaluated by the following procedure. The post-glue pressure-bonded recording paper obtained above was folded so that the pseudo-adhesive layers faced each other, and was pressure-bonded using a pressure sealer (MS-9100 manufactured by Dai Nippon Printing Co., Ltd.) under a sealer gap of 7. The paper was then peeled off immediately after bonding and evaluated according to the following criteria. (Evaluation Criteria) ◎: The paper was peeled off without tearing. ◯: The paper peels off without tearing, but the peel strength is so strong that cracks may appear on the adhesive surface. △: It stuck together and when I tried to remove it the paper ripped. ×: Unable to judge because not adhered from the beginning.

[0094] The above measurement results and evaluation results are shown in Table 3.

[0095] [Table 3]

[0096] As shown in Table 3, the post-adhesive compression recording base papers of Examples 1 to 9, which satisfy the above requirements for the base paper and coating layer configuration, the primary particle size of the precipitated calcium carbonate, the peel strength in the Z-axis direction, and the toluene oil absorption, were excellent in print density and ink drying properties, and had good inkjet printability. In addition, the post-adhesive compression recording papers obtained from the post-adhesive compression recording base papers of Examples 1 to 9 were excellent in removability, and no breakage of the base paper was observed during re-peeling.

[0097] On the other hand, in Comparative Examples 1 to 7 which do not satisfy the above requirements, the post-glue pressure-bonded recording base paper was inferior in either print density or ink drying property, or the post-glue pressure-bonded recording paper was inferior in either removability or base paper tearing during removal. Specifically, Comparative Example 1, in which the coating layer does not contain an organic pigment, had a reduced print density. Comparative Example 2, in which the coating layer contains an organic pigment, the content of light calcium carbonate is more than 69% by mass, the content ratio of kaolin is less than 30% by mass, and the toluene oil absorption is 100 seconds or less, had poor post-glue suitability in UV-based glue. In addition, Comparative Example 3, in which the content of kaolin in the coating layer is more than 50% by mass and the mass ratio of the kaolin to the light calcium carbonate is more than 1.20, had poor ink-jet ink absorption and reduced print density. Comparative Example 4, in which the primary particle diameter of the light calcium carbonate is more than 0.50 μm, had a reduced print density. Furthermore, in Comparative Example 5, in which the base paper did not contain a paper strength enhancer, the peel strength was low, and when the post-adhesive pressure-bonded recording paper was used, the substrate broke when it was peeled off again. In Comparative Example 6, in which the base paper did not contain a sizing agent, the water-based glue penetrated into the coating layer, and the post-adhesive pressure-bonded recording paper did not have adhesiveness, so it was not possible to evaluate the ability to suppress base paper breakage when peeled off again. In Comparative Example 7, in which the coating layer did not contain light calcium carbonate but contained heavy calcium carbonate, the ink drying properties were poor and the print density was reduced. [Industrial Applicability]

[0098] This post-glue pressure-bonded recording base paper has suitability for offset printing and inkjet printing, and has excellent releasability while maintaining adhesion, and is particularly suitable for use as a base paper for post-glue pressure-bonded recording paper used for mailing applications, particularly for inkjet printing.

Claims

1. A base paper and a coating layer laminated on at least one surface of the base paper; Equipped with The base paper contains a paper strength agent and a sizing agent, The coating layer contains a pigment and a binder, The coating layer contains, as the pigment, light calcium carbonate, kaolin and an organic pigment, the content ratio of the precipitated calcium carbonate to the total pigment of the coating layer is 40% by mass or more and 69% by mass or less, The content ratio of the kaolin to the total pigment of the coating layer is 30% by mass or more and 50% by mass or less, the content ratio of the organic pigment to the total pigment of the coating layer is 1% by mass or more and 10% by mass or less; a mass ratio of the kaolin to the precipitated calcium carbonate in the coating layer is 0.50 or more and 1.20 or less, and a mass ratio of the organic pigment to the precipitated calcium carbonate in the coating layer is 0.03 or more and 0.25 or less, The primary particle size of the precipitated calcium carbonate is 0.05 μm or more and 0.50 μm or less, The peel strength in the Z-axis direction is 700 kPa or more, The toluene absorption rate is 100 seconds or more, The post-adhesive pressure-bonding recording base paper has a dense organic pigment shape.

2. A base paper and a coating layer laminated on at least one surface of the base paper; Equipped with The base paper contains a paper strength agent and a sizing agent, The coating layer contains a pigment and a binder, The coating layer contains, as the pigment, light calcium carbonate, kaolin and an organic pigment, the content ratio of the precipitated calcium carbonate to the total pigment of the coating layer is 40% by mass or more and 69% by mass or less, The content ratio of the kaolin to the total pigment of the coating layer is 30% by mass or more and 50% by mass or less, the content ratio of the organic pigment to the total pigment of the coating layer is 1% by mass or more and 10% by mass or less; a mass ratio of the kaolin to the precipitated calcium carbonate in the coating layer is 0.50 or more and 1.20 or less, and a mass ratio of the organic pigment to the precipitated calcium carbonate in the coating layer is 0.03 or more and 0.25 or less, The primary particle size of the precipitated calcium carbonate is 0.05 μm or more and 0.50 μm or less, The peel strength in the Z-axis direction is 700 kPa or more, The toluene absorption rate is 100 seconds or more, The precipitated calcium carbonate is an aggregate of primary particles, The post-adhesive pressure-bonding recording base paper has a cubic shape as the primary particles.

3. A base paper and a coating layer laminated on at least one surface of the base paper; Equipped with The base paper contains a paper strength agent and a sizing agent, The coating layer contains a pigment and a binder, The coating layer contains, as the pigment, light calcium carbonate, kaolin and an organic pigment, the content ratio of the precipitated calcium carbonate to the total pigment of the coating layer is 40% by mass or more and 69% by mass or less, The content ratio of the kaolin to the total pigment of the coating layer is 30% by mass or more and 50% by mass or less, the content ratio of the organic pigment to the total pigment of the coating layer is 1% by mass or more and 10% by mass or less; a mass ratio of the kaolin to the precipitated calcium carbonate in the coating layer is 0.50 or more and 1.20 or less, and a mass ratio of the organic pigment to the precipitated calcium carbonate in the coating layer is 0.03 or more and 0.25 or less, The primary particle size of the precipitated calcium carbonate is 0.05 μm or more and 0.50 μm or less, The peel strength in the Z-axis direction is 700 kPa or more, The toluene absorption rate is 100 seconds or more, A post-glue pressure-bonding recording base paper having a Cobb sizing degree of 10 g / m 2 or more and 50 g / m 2 or less.

4. A base paper and a coating layer laminated on at least one surface of the base paper; Equipped with The base paper contains a paper strength agent and a sizing agent, The coating layer contains a pigment and a binder, The coating layer contains, as the pigment, light calcium carbonate, kaolin and an organic pigment, the content ratio of the precipitated calcium carbonate to the total pigment of the coating layer is 40% by mass or more and 69% by mass or less, The content ratio of the kaolin to the total pigment of the coating layer is 30% by mass or more and 50% by mass or less, the content ratio of the organic pigment to the total pigment of the coating layer is 1% by mass or more and 10% by mass or less; a mass ratio of the kaolin to the precipitated calcium carbonate in the coating layer is 0.50 or more and 1.20 or less, and a mass ratio of the organic pigment to the precipitated calcium carbonate in the coating layer is 0.03 or more and 0.25 or less, The primary particle size of the precipitated calcium carbonate is 0.05 μm or more and 0.50 μm or less, The peel strength in the Z-axis direction is 700 kPa or more, The toluene absorption rate is 100 seconds or more, Further comprising an undercoating layer, The above coating layer is laminated on the surface of the undercoating layer to form a post-glue pressure-bonded recording base paper.

5. A post-adhesive pressure-bonding recording paper using the post-adhesive pressure-bonding recording base paper according to any one of claims 1 to 4.

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