JPWO2020255473A1 - Printing paper with hinges - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing paper which can print on a periphery of a hinge portion and which prints of left and right pages are seamlessly connected when opened in a double-page spread so as to be easy to see. A printing paper 10 includes a base material layer which is a thermoplastic resin film including a porous layer, and a printing layer laminated on at least one surface of the base material layer, and the printing paper 10 includes a base material layer. It has a linear hinge portion 11 recessed in the thickness direction. Since the hinge portion 11 is formed by heating and pressurizing the printing paper 10 containing the thermoplastic resin film, characters and images can be printed up to the periphery of the hinge portion 11. [Selection diagram] Fig. 1

Description

The present invention relates to a printing paper having a hinge portion. The printing paper according to the present invention is used, for example, as a booklet in which a plurality of printing papers are stacked. In particular, the printing paper according to the present invention is suitable for printing paper such as a photo album that is viewed in a two-page spread.

Conventionally, a bookbinding method has been known in which a plurality of pages printed with photographs or the like are stacked, aligned on the spine, and the pages are combined at a binding portion provided around the edge of the spine. .. For example, when joining pages for a photo book, hot melt adhesive is applied around the spine to join the pages, or multiple holes are formed so as to penetrate the binding part of each page. It is common to insert a screw (bookbinding screw) into this hole to connect the pages.

By the way, in the bookbinding method as described above, it is difficult for the left and right pages to become flat when the booklet is opened in a two-page spread, and it is pointed out that if you try to open it flat forcibly, the pages and bookbinding may be damaged. (Patent Document 1). In order to overcome such a problem, in Patent Document 1, an opening is formed along the binding portion of each page, and a flexible film is attached so as to cover the opening portion. A sheet stock has been proposed in which a hinge area is formed by the film and the film to make each page easier to bend.

Special Table 2010-52099

However, when an opening is formed in each printing paper and a flexible film is attached on the opening as in the sheet stock described in Patent Document 1, the space between the printing paper and the film is around the opening. Will cause a step. In this case, when printing is attempted around the opening, printing may be disturbed due to a step between the printing paper and the film. Further, depending on the material of the flexible film, it may be difficult to print on the flexible film. For this reason, it is a practical measure to avoid printing around the openings of each printing paper by avoiding flexible films, but doing so is the central part of the double-page spread ( An area that cannot be printed is created around the binding area), and the photographs printed on the left and right pages become discontinuous. Then, the significance of opening the left and right pages flat will be lost.

Therefore, the present invention is a printing paper having a hinge portion and can be opened flat, and can be easily printed on the periphery of the hinge portion, so that the left and right pages can be printed seamlessly when opened in a double-page spread. The purpose is to provide something that is connected and easy to see.

As a result of diligent studies on means for achieving the above object, the inventor of the present invention has formed a concave linear hinge portion on a printing paper made of a thermoplastic resin film containing a porous layer. We have obtained the finding that printing can be performed up to the edge of the hinge part (recess). Then, the present inventor has come up with the idea that the problems of the prior art can be solved based on the above findings, and has completed the present invention.

Specifically, the present invention relates to printing paper. The printing paper according to the present invention is formed by laminating a base material layer and a printing layer. The base material layer is made of a thermoplastic resin film including a porous layer. The printed layer is laminated on one or both surfaces of the base material layer, and characters, images, and the like can be recorded by printing. The printing paper according to the present invention has a linear hinge portion recessed in the thickness direction of the printing paper. The hinge portion is preferably linear, but may be curved or polygonal. The hinge portion can be formed, for example, by pressing the printing paper while heating it. The base material layer contained in the printing paper is compressed by heating and pressurizing, and a concave hinge portion is formed.

As described above, the printing paper according to the present invention is a continuous printing paper containing a porous thermoplastic resin film in which a concave hinge portion is formed. Therefore, the sheet stock described in Patent Document 1 It is not necessary to make an opening in the sheet or to attach a flexible film on the opening. Therefore, with the printing paper of the present invention, printing can be easily performed even just before the hinge portion. As a result, when the booklet bound with each printing paper is opened in a two-page spread, the central part (around the binding part) can be printed with uniform quality, so that the characters and images printed on the left and right pages can be printed. Are seamlessly connected to make it easier to see. Further, since it is not necessary to form an opening or attach a flexible film, according to the present invention, the material cost and the manufacturing cost of the printing paper can be suppressed at low cost. Further, the printing paper of the present invention is easy to bend along the concave hinge portion, and is naturally easy to open flat when spread.

In the printing paper according to the present invention, the paper thickness in the region other than the hinge portion is preferably 80 to 600 μm, and the paper thickness in the hinge portion is preferably 10 to 85% of the paper thickness in the region other than the hinge portion. In the specification of the present application, the “region other than the hinge portion” means a flat printed portion on which characters and images are printed. Assuming that printing paper is used for general photo book applications, the thickness of the printing paper is 80 to 600 μm as described above, so that appropriate rigidity is generated and bending is less likely to occur, and the printing paper is concave. It becomes easy to form a hinge part. Further, when the paper thickness at the hinge portion is 10 to 85% of the paper thickness of the printing paper, an appropriate strength is generated in the hinge portion to prevent the hinge portion from breaking, and the printing paper can be easily bent at the hinge portion.

In the printing paper according to the present invention, the width of the hinge portion is preferably twice or more the depth of the hinge portion. This makes it easier to maintain the folded state of the printing paper at the hinge portion. The upper limit of the width of the hinge portion is not particularly limited, but it is preferably 5 times or less or 4 times or less the depth of the hinge portion.

In the printing paper according to the present invention, it is preferable that the base material layer is formed of a polyolefin resin. As the thermoplastic resin, polyethylene terephthalate (PET) -based resin or styrene-based resin can be used, but it is particularly preferable to use a polyolefin (PO) -based resin having both strength and flexibility to withstand repeated bending of the hinge portion. ..

In the printing paper according to the present invention, the porosity of the base material layer in the hinge portion is preferably lower than the porosity of the base material layer in the region other than the hinge portion. As described above, in the present invention, it is preferable to form a hinge portion having a predetermined shape by heating and pressurizing a part of the printing paper, but at that time, the porosity of the porous layer of the base material layer is lowered. Will be done. By reducing the porosity of the porous layer in the hinge portion, the strength of the hinge portion can be increased or the opacity can be lowered.

In the printing paper according to the present invention, the porosity of the base material layer in the region other than the hinge portion is preferably 10 to 45%. This makes it possible to form a hinge portion having a preferable shape. That is, if the porosity of the base material layer is too low, the base material layer is less likely to be crushed even when heat and pressure are applied, so that it is difficult to obtain a hinge portion having a desired depth. On the other hand, if the porosity of the base material layer is too high, the paper may be torn when the hinge portion is formed by heating and pressurizing, or it becomes difficult to maintain the strength of the hinge portion. Therefore, it is appropriate that the porosity of the base material layer is within the above range.

In the printing paper according to the present invention, the Clark rigidity (S value) in the hinge portion is preferably 10 to 250, and the Clark rigidity (S value) in the region other than the hinge portion is preferably 15 to 500. The Clark rigidity (S value) of the hinge portion is lower than that of the other regions. By setting the Clark rigidity (S value) in the hinge portion to 10 to 250 as in the above configuration, it becomes easy to bend naturally and it is possible to provide strength that can withstand repeated bending. In addition, by setting the Clark rigidity (S value) of the area other than the hinge part (especially the printing part) to a high value of 15 to 500, the left and right pages tend to be flattened naturally when the pages are spread, and the printing paper can be used as a photo book. It can be suitably used for the above-mentioned applications.

In the printing paper according to the present invention, the hinge portion is preferably formed in a straight line parallel to one side of the rectangular printing paper. Further, it is preferable that the printing paper has a region (reinforcing portion) in which the hinge portion is not formed between the other two sides orthogonal to one side of the printing paper parallel to the hinge portion and the hinge portion. .. When printing on printing paper, a reinforcing part is provided between the hinge part and the edge of the printing paper, so that the printing paper can be prevented from being bent or bent unintentionally, so that it is accurate. Printing processing becomes possible. Further, when binding the printed printing paper, the reinforcing portion is cut off so that the printing paper can be easily bent at the hinge portion. As described above, the reinforcing portion is provided on the printing paper on the premise that it is finally cut off.

According to the present invention, printing can be easily applied to the periphery of the hinge portion of the printing paper, and the left and right pages are seamlessly connected and easy to see when opened in a double-page spread.

FIG. 1 is a plan view schematically showing a printing paper according to an embodiment of the present invention. 1 (a) shows the printing paper before the printing process, FIG. 1 (b) shows the cut portion of the printing paper with a alternate long and short dash line, and FIG. 1 (c) shows the space between the hinge portion and the edge of the printing paper. It shows the state where the reinforcing part of is cut off. FIG. 2 schematically shows the cross-sectional structure of the line II-II shown in FIG. FIG. 2A shows a pattern in which a concave hinge portion is formed on one side of the printing paper, and FIG. 2B shows a pattern in which a concave hinge portion is formed on both sides of the printing paper. FIG. 2C shows a pattern in which the bottom surface of the hinge portion has a semicircular cross section as a modification of FIG. 2A. FIG. 3 schematically shows a method for aptitude evaluation test of a hinge portion of printing paper.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the form described below, and includes those appropriately modified from the following forms to the extent apparent to those skilled in the art.
In the specification of the present application, "A to B" means "A or more and B or less".

FIG. 1 is a plan view schematically showing a printing paper 10 according to an embodiment of the present invention. Characters and images can be printed on the front surface and the back surface of the printing paper 10. In particular, the printing paper 10 according to this embodiment is assumed to be used for printing photographic images on both the front and back surfaces. A photo album (booklet) can be created by superimposing a plurality of printing papers 10 on which a photographic image is printed and binding one end of each printing paper 10.

As shown in FIG. 1A, the printing paper 10 has a linear hinge portion 11 recessed in the thickness direction. That is, the printing paper 10 has a small paper thickness only at the hinge portion 11, and the paper thicknesses in the other regions are almost the same. As described above, the printing paper 10 has a feature that the hinge portion 11 is easily bent along the hinge portion 11 because the paper thickness of the hinge portion 11 is smaller than that of the other regions.

The hinge portion 11 extends in the vicinity of one side of the printing paper 10 in parallel with the one side. Specifically, the printing paper 10 according to the present embodiment has a rectangular shape and has two short sides 10a and 10b and two long sides 10c and 10d orthogonal to these. Since the printing paper 10 of the present embodiment is intended to be used sideways, the hinge portion 11 is formed in the vicinity of one short side 10b of the four sides of the printing paper 10. When the printing paper 10 is used in the vertical orientation, the hinge portion 11 may be formed in the vicinity of any of the long sides 10c and 10d.

The printing paper 10 is provided with a binding portion 13 between the hinge portion 11 and one short side 10b in the vicinity thereof, and further, a printing portion 12 is provided between the hinge portion 11 and the other short side 10a. The printing unit 12 is an area for printing characters and images, and occupies most of the printing paper 10. The binding unit 13 is an area used for binding the printing papers 10 when the plurality of printing papers 10 are stacked and bound. For example, an adhesive such as a hot melt adhesive may be applied to the binding portion 13 of each printing paper 10 to join the short sides of each printing paper 10. Further, small holes may be formed at a plurality of locations so as to penetrate the binding portion 13 of each printing paper 10, and screws (bookbinding screws) may be inserted into the small holes to connect the printing paper 10. Further, the binding portion 13 of each printing paper 10 may be bound by using a thread, a wire, a staple, or the like. The bookbinding method is not limited to the one described here, and a known method can be appropriately adopted. The width of the binding portion 13 may be appropriately adjusted according to the bookbinding method, but may be, for example, 5 to 50 mm.

In the printing paper 10 before printing, a reinforcing portion 14 having no recess is provided between the hinge portion 11 having a concave recess and the two long sides 10c and 10d. That is, the reinforcing portion 14 has substantially the same paper thickness as the region other than the hinge portion 11. In other words, the paper thickness at the reinforcing portion 14 is larger than that at the hinge portion 11. The width of the reinforcing portion 14 (the gap between the hinge portion 11 and the long sides 10 and 10d) is preferably 1 to 20 mm, and particularly preferably 2 to 10 mm. As described above, in the printing paper 10 before the printing process, by providing the reinforcing portions 14 on both ends in the longitudinal direction of the hinge portion 11, the printing paper 10 is less likely to bend when the printing paper 10 is applied to the printing machine. Therefore, the printing process can be performed accurately.

Further, the printing paper 10 after the printing process has the long sides 10c and 10d of the printing paper 10 so as to cross the positions shown by the alternate long and short dash lines in FIG. 1B, that is, both ends in the longitudinal direction of the hinge portion 11. It is cut along a parallel cutting line. As a result, the reinforcing portions 14 located on both ends in the longitudinal direction of the hinge portion 11 are cut off. As shown in FIG. 1 (c), the printing paper 10 after the cutting process has the hinge portions 11 reaching the two long sides 10c and 10d. As described above, in the printing paper 10 after the cutting process, the hinge portion 11 is located between two sides (10c, 10d) orthogonal to the one side (10b) in the vicinity of one side (10b) of the rectangular printing paper 10. It is formed so as to extend in parallel with the one side (10b). This makes it easier to bend the printing paper 10 along the hinge portion 11.

FIG. 2 schematically shows the cross-sectional structure of the line II-II shown in FIG. In FIG. 2, a pattern in which the hinge portion 11 is formed by providing a recess on one side of the printing paper 10 (FIG. 2A) and a pattern in which the hinge portion 11 is formed by providing recesses on both sides of the printing paper 10 (FIG. 2A). FIG. 2 (b)) is shown. As a feature common to both patterns, the printing paper 10 has a structure in which a base material layer A including a porous layer and printing layers B1 and B2 provided on both sides of the base material layer A are laminated in the thickness direction. ing. In this embodiment, since it is assumed that printing is performed on both sides of the printing paper 10, the printing layers B1 and B1 are laminated on both the front and back surfaces of the base material layer A. However, when printing is performed on only one side of the printing paper 10, the printing layer may be laminated only on one side of the base material layer A. Further, as shown in FIG. 2C, the bottom surface of the hinge portion 11 can have a semicircular cross section.

In the present invention, the base material layer A is made of a thermoplastic resin film. By using the thermoplastic resin film as the base material layer A, it is possible to impart mechanical strength such as stiffness, water resistance, chemical resistance, opacity and the like, if necessary, to the printing paper 10.

The thermoplastic resin used for the base material layer A is not particularly limited, and is, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin; a polyester resin such as polyethylene terephthalate or polylactic acid; nylon-6, nylon-6, 6. Polyamide resin such as nylon-6,12; styrene resin such as polystyrene, acrylonitrile-styrene (AS) copolymer, styrene-butadiene (SBR) copolymer; polyvinyl chloride resin; polycarbonate resin; polyphenylene sulfide And so on. Two or more of these resins can be mixed and used. Among them, the thermoplastic resin constituting the base material layer A is preferably a polyolefin resin because it has both strength and flexibility to withstand repeated bending of the hinge portion. In particular, from the viewpoint of film formability, it is more preferable to use a polypropylene-based resin among the polyolefin-based resins. Examples of polypropylene-based resins include isotactic homopolypropylene obtained by homopolymerizing propylene, syndiotactic homopolypropylene, and propylene as a main component, ethylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-. Examples thereof include polypropylene-based copolymers having various steric regularities obtained by copolymerizing α-olefins such as 1-pentene, 1-heptene and 1-octene. The polypropylene-based copolymer may be a binary system or a multi-dimensional system having a ternary system or more, and may be a random copolymer or a block copolymer.

The base material layer A can contain a filler for adjusting the rigidity, whiteness, and opacity. Examples of the filler include an inorganic filler such as calcium carbonate and an organic filler such as resin particles, and these can be used alone or in combination. When the thermoplastic resin film containing the filler is stretched, a large number of fine pores with the filler as the core are formed inside the base material layer A. This makes it possible to whiten, opaque and reduce the weight of the base material layer A. When the base material layer A contains the filler in this way, a porous layer is formed inside the base material layer A.

The average particle size of the filler is preferably large from the viewpoint of ease of mixing with the thermoplastic resin, and when the pores are generated inside by stretching, the sheet is cut during stretching and the strength of the base material layer A is strong. From the viewpoint of making it difficult for troubles such as deterioration to occur, it is preferable that the size is small. Specifically, it is preferably 0.01 μm or more, more preferably 0.1 μm or more, and further preferably 0.5 μm or more. Further, it is preferably 30 μm or less, more preferably 20 μm or less, and further preferably 15 μm or less. The average particle size of the filler was measured by observing the cut surface of the base material layer A with an electronic microscope and measuring the maximum diameter of at least 10 particles, and the average value was dispersed in the thermoplastic resin by melt kneading and dispersion. It can be obtained as the average dispersed particle size at the time.

The content of the filler in the base material layer A is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and more preferably 5% by mass or more, from the viewpoint of obtaining a desired porosity. It is preferably 45% by mass or less, more preferably 40% by mass or less, and further preferably 35% by mass or less.

In addition, the base material layer A can optionally contain a known additive, if necessary. Further, the base material layer A may have a single-layer structure or a multi-layer structure. In the case of multiple layers, by providing a solid printing layer or a pigment-containing layer on the inside as a concealing layer, the printing on the other side does not show through when viewed from one side, and the visibility at the time of double-sided printing is also improved. It is also possible to obtain a recording paper suitable for printing paper such as a photographic image.

In the portion where the hinge portion 11 is not formed (particularly the printed portion 12), the porosity representing the ratio of the pores in the base material layer A is preferably 10% or more, and preferably 12% or more. More preferably, it is more preferably 15% or more, and particularly preferably 20% or more. The porosity of the printing unit 12 is preferably 45% or less, more preferably 44% or less, further preferably 42% or less, and particularly preferably 40% or less.

The porosity can be measured by observing the cross section of the base material layer with an electron microscope as described in JP-A-2019-48433. Specifically, the method for measuring the porosity can be obtained from the ratio of the area occupied by the pores in a certain region of the cross section of the printing paper observed with an electron microscope. Specifically, an arbitrary part of the printing paper is cut out, embedded in an epoxy resin and solidified, and then cut perpendicularly to the surface direction of the substrate using a microtome so that the cut surface becomes an observation surface. Attach to the observation sample stand. Gold or gold-palladium is deposited on the observation surface, pores are observed at an arbitrary magnification that is easy to observe with an electron microscope (for example, a magnification of 500 to 3000 times), and the observed area is captured as image data. .. The obtained image data can be subjected to image processing by an image analysis device to obtain the area ratio of the porosity portion, and the porosity can be obtained. In this case, the porosity can be obtained by averaging the measured values at any 10 or more observation points.

The print layers B1 and B2 are layers capable of recording characters, images, and the like by printing. The printed layer can be formed by corona treatment, frame treatment, plasma treatment, coating and drying of paint, extrusion laminating of molten resin, and the like on the surface of the base material layer A. As the printing method on the print layers B1 and B2, various printing methods such as offset printing, inkjet method, electrophotographic (laser) method, thermal recording method, and thermal transfer method can be used. Further, the printing layer B1 or B2 is previously provided on one surface of the support film that follows the base layer A when forming the hinge portion, which is extremely thin and flexible as compared with the base layer A, by the above method. May be laminated on the base material layer A via the adhesive layer. For example, a layer made of an adhesive such as a water-based adhesive, a solvent-based adhesive, or a hot-melt adhesive is placed on the opposite side of the support film from the printed layers B1 and B2 by a method such as coating, spraying, or melt extrusion molding. After forming the adhesive layer on the surface of the above, the base material layer A may be laminated on the adhesive layer. Further, after the adhesive layer is provided on the base material layer A, the support films provided with the print layers B1 and B2 on one surface may be laminated. Further, an adhesive may be melt-extruded and pressure-bonded between the base material layer A and the support film provided with the printing layers B1 and B2 for laminating.
As yet another embodiment, at least one of the printed layers B1 and B2 formed on one surface of the above-mentioned support film is pre-printed, and then laminated on the base material layer A via the adhesive layer. May be good.

In the pattern shown in FIG. 2A, a recess for forming the hinge portion 11 is provided only on one side (front surface) side of the printing paper 10 having the laminated structure. In order to form such a concave portion, it is preferable to heat and pressurize the printing paper 10 in the thickness direction by a press machine having a convex portion having a shape corresponding to the concave portion. The configuration of the press machine is not particularly limited, and a known one can be appropriately adopted. For example, the printing paper 10 may be introduced between a press roller formed on a peripheral surface in which a convex portion having a predetermined shape can be heated and an anvil roller having a flat peripheral surface. Further, a flat plate may be used instead of the anvil roller. As described above, the base material layer A of the printing paper 10 is made of a thermoplastic resin film including a porous layer. Therefore, by pressurizing the printing paper 10 while locally heating it, the base material layer A is partially melted, and the pores in the porous layer are crushed to reduce the volume of the pressed portion. Decrease. As a result, a recess is formed in the pressurized portion, and the recess functions as the hinge portion 11.

Further, in the pattern shown in FIG. 2A, it is preferable that the width W of the recess functioning as the hinge portion 11 is twice or more the depth D of the recess. Specifically, the width W of the recess is preferably 2 to 5 times, and particularly preferably 2.1 to 4 times or 2.2 to 3 times the depth D of the recess. By setting the width W of the recess to be more than twice the depth D, it is possible to prevent the side walls of the recess from interfering with each other when the printing paper 10 is bent at the center of the recess, so that printing can be performed. The paper 10 can be easily bent naturally at the hinge portion 11. The width W of the recess may be 0.5 to 40 mm, preferably 1 to 30 mm, and particularly preferably 2 to 20 mm. The depth D of the recess may be 40 to 400 μm, preferably 60 to 350 μm, and particularly preferably 100 to 300 μm. As shown in FIG. 2C, when the bottom surface of the recess has a semicircular cross section, the depth D of the recess means the depth of the deepest portion of the recess.

On the other hand, in the pattern shown in FIG. 2B, recesses for forming the hinge portion 11 are provided on both the front surface and the back surface of the printing paper 10 having the laminated structure. The two recesses are formed at the same position when viewed in the thickness direction of the printing paper 10. In order to form such a concave portion, the printing paper 10 can be heated and pressed in the thickness direction by a press machine having a convex portion having a shape corresponding to the concave portion, as in the pattern of FIG. 2A. preferable. The configuration of the press machine is not particularly limited, and a known one can be appropriately adopted. For example, the printing paper 10 may be introduced between two press rollers having a convex portion having a predetermined shape formed on a peripheral surface that can be heated, and the printing paper 10 may be sandwiched between the convex portions of the press rollers. As a result, a recess is formed in the pressurized portion, and the recess functions as the hinge portion 11.

In the pattern shown in FIG. 2B, the width W1 of the recess formed on the front surface and the width W2 of the recess formed on the back surface are both preferably equal values, but may be different values. For example, the width W1 of the recess on the front surface is preferably 90 to 110% or 95 to 105% with respect to the width W2 of the recess on the back surface, but may be, for example, 10 to 95% or 50 to 90%. .. By intentionally making the widths W1 and W2 of the concave portions on the front surface and the back surface different, the printing paper 10 can be easily bent in a certain direction. Similarly, the depth D1 of the recess formed on the front surface and the depth D2 of the recess formed on the back surface are both preferably equal values, but can be different values. For example, the depth D1 of the concave portion on the front surface is preferably 90 to 110% or 95 to 105% with respect to the depth D2 of the concave portion on the back surface, and is, for example, 10 to 95% or 50 to 90%. You can also. By intentionally making the depths D1 and D2 of the recesses on the front surface and the back surface different, the printing paper 10 can be easily bent in a certain direction.

Further, also in the pattern shown in FIG. 2B, it is preferable that the widths W1 and W2 of the recesses functioning as the hinge portions 11 are twice or more each of the depths D1 and D2 of the recesses. Specifically, the widths W1 and W2 of the recesses are preferably 2 to 5 times, respectively, and 2.1 to 4 times or 2.2 to 3 times the depths of the recesses D1 and D2, respectively. Is particularly preferable. The widths W1 and W2 of the recesses may be 0.5 to 40 mm, preferably 1 to 30 mm, and particularly preferably 2 to 20 mm.

In both the patterns of FIGS. 2A and 2B, the paper thickness T of the portion where the hinge portion 11 is formed is the other region (particularly the printing portion 12) where the hinge portion 11 is not formed. Naturally, it is smaller than the paper thickness P. The paper thickness T of the hinge portion 11 is preferably 10 to 85%, more preferably 40 to 80%, and particularly preferably 50 to 75% with respect to the paper thickness P of the other region. .. By keeping the paper thickness T of the hinge portion 11 within the above range, it is possible to achieve both the ease of folding the printing paper 10 and the strength of the printing paper at the hinge portion 11. Further, when it is assumed that the printing paper 10 is used for a photo album, a certain thickness is required in order to suppress the bending of the paper. Therefore, the paper thickness P of the printing paper is preferably 80 to 600 μm. Further, the paper thickness P is more preferably 100 to 500 μm, and particularly preferably 150 to 450 μm. As shown in FIG. 2C, when the bottom surface of the recess has a semicircular cross section, the paper thickness T at the portion where the hinge portion 11 is formed means the paper thickness at the deepest portion of the recess.

The rigidity of the printing unit 12 of the printing paper 10 is MD (flow direction), TD (flow direction), as Clark rigidity (S value) (hereinafter, simply referred to as “Clark rigidity”) measured in accordance with JIS-P-8143. It is preferably in the range of 15 to 500, more preferably in the range of 40 to 400, and particularly preferably in the range of 80 to 300 in both eye directions (in the width direction). When the Clark rigidity of the printing paper 10 is within the above range, stable running performance on a printing machine without causing trouble can be obtained. If the Clark rigidity is less than 15 in either the MD or TD direction, there is a possibility that the paper feed section of the printing press may be bent or the paper feed may be defective due to heavy running. In addition, the printing paper tends to be wrinkled. On the other hand, if it exceeds 500, the paper may run wild without following the running part of the printing press, or printing at high speed may be difficult, and if the rigidity is too high, the blanket may be broken due to a paper jam. There is also. When the Clark rigidity is within the above range for both MD and TD regardless of the direction of the printing paper 10, the degree of freedom of imposition of printing is improved, which is more preferable in practice at the time of printing processing.

Further, the clerk rigidity of the hinge portion 11 of the printing paper 10 is preferably in the range of 10 to 250 in both the MD and TD directions, more preferably in the range of 20 to 200, and in the range of 50 to 150. It is particularly preferable to have. The clerk rigidity of the hinge portion 11 is naturally lower than that of the printing portion 12, but by keeping it within the above range, the strength that can withstand repeated bending is maintained, and when the hinge portion 11 is bound into a booklet and opened in a spread. It makes it easier to keep the left and right pages flat and naturally. That is, when the Clark rigidity of the hinge portion 11 is less than 10, the strength of the paper surface becomes weak, and there is a concern that the paper surface may break during repeated bending. On the other hand, when the clerk rigidity of the hinge portion 11 exceeds 250, it becomes difficult to bend the printing paper 10 at the hinge portion 11, and it becomes difficult to maintain the open state in the spread after binding the booklet into a booklet. Therefore, by adjusting the Clark rigidity of the hinge portion 11 within the above range, the ease of use of the booklet created by using the printing paper 10 can be improved.

In the printing paper 10, the porosity of the base material layer A in the hinge portion 11 is lower than the porosity of the base material layer A in other regions (particularly the printing portion 12). For example, the porosity of the hinge portion 11 is preferably 0 to 90%, more preferably 5 to 60%, and 10 to 50% when the porosity of the printed portion 12 is 100%. It is particularly preferable to have. Specifically, the porosity of the hinge portion 11 measured by the above-mentioned method is preferably 0 to 20%, and preferably 1 to 10% or 1 to 5%. Since the porosity of the hinge portion 11 is lower than that of other portions, the density of the base material layer A in the hinge portion 11 is increased, so that the strength of the hinge portion 11 can be maintained accordingly. That is, since the paper thickness of the hinge portion 11 is smaller than that of other portions, the strength of the hinge portion 11 is unavoidably reduced, but the porosity of the base material layer A in the hinge portion 11 is reduced to reduce the resin. By increasing the density of the paper, it is possible to alleviate the tendency of the strength to decrease as the paper thickness decreases.

The opacity of the hinge portion 11 of the printing paper 10 is preferably lower than the opacity of the other regions (particularly the printing portion 12). That is, the printing unit 12 needs to have high opacity so that characters and images can be clearly displayed and the printing on the opposite side cannot be seen through. On the other hand, the hinge portion 11 has a relatively low opacity (that is, the hinge portion 11 is made translucent), so that when a plurality of printing papers 10 are stacked, the hinge portion of each printing paper 11 is made transparent. The alignment of 11 becomes easy. Further, when the printing paper 10 is placed on a printing machine, it is conceivable that the printing machine identifies the hinge portion 11 and the printing portion 12 of the printing paper 10 and prints an image or the like on the printing unit 12. In this case, by lowering the opacity of the hinge portion 11 to make a difference from the opacity of the printing portion 12, for example, the image sensor in the printing machine makes it easy to distinguish between the hinge portion 11 and the printing portion 12. For example, the opacity of the hinge portion 11 is preferably 10 to 95%, more preferably 20 to 90%, and 30 to 80% when the opacity of the printing portion 12 is 100%. It is particularly preferable to have. Specifically, the opacity of the hinge portion 11 is preferably 80% or less, and is 75% or less or 70% or less when measured by the opacity measuring method specified in JIS-P-8149. Is particularly preferred. On the other hand, when measured by the same measuring method, the opacity of the printed portion 12 is preferably 85% or more, and particularly preferably 87% or more or 89% or more.

Regarding the printing paper according to the present invention, the following verification was performed in order to obtain an appropriate ratio of the paper thickness T of the hinge portion to the paper thickness P of the printing paper (see FIG. 2 for each reference numeral).

Specifically, as the printing paper, in Examples 1 to 3 and Comparative Example 1, the polyolefin-based synthetic paper “YPI 250” manufactured by Yupo Corporation (paper thickness 250 μm, Clark rigidity (S value) MD: 180, TD). : 370) was used. Further, in Examples 4 to 9 and Comparative Example 2, the polyolefin-based synthetic paper "Ultra YUPO (R) FEB 250" (thickness 250 μm, Clark rigidity (S value) MD: 210, TD: 439) manufactured by Yupo Corporation was used. used. The above printing paper is cut into a rectangle 21 cm in the TD direction and 30 cm in the MD direction, sandwiched between silicon release papers, and a hinge portion having a width of 5 mm parallel to the TD direction is formed by hot pressing at 140 ° C. and 0.1 MPa. Was formed from one end to the other. The width of the binding portion was 10 mm, and the depth of the hinge portion was adjusted so that the "ratio of the paper thickness of the hinge portion to the paper thickness of the printing paper" was the value shown in Table 1. With respect to the obtained printing paper with a hinged portion, the paper thickness T of the hinged portion, the ratio of the paper thickness T of the hinged portion to the paper thickness P of the printing paper, and the Clark rigidity (S value) in the TD direction were measured. In addition, the hinge suitability was evaluated for each Example and each Comparative Example by the following method. The results are shown in Table 1.

[Evaluation criteria for hinge suitability]
The method of the aptitude evaluation test of the hinge part is shown in FIG. The end of the created printing paper with a hinged portion on the binding portion side was fixed with a fixture, and after the printing paper was erected vertically, the angle between the binding portion and the printing portion when the hand was released was measured (). Test 1). In addition, the breakability of the hinge portion was confirmed when the operation of strongly bending to 0 ° was repeated 50 times from the state where the angle formed by the binding portion and the printing portion was 180 ° (Test 2). Based on the results of Test 1 and Test 2, the appropriateness of the hinge portion was evaluated as follows.
A: The angle between the binding part and the printing part is 90 ° or less, and it does not break even after repeated bending.
B: The angle formed by the binding portion and the printing portion is larger than 90 °, 135 ° or less, and does not break even after repeated bending.
C: The angle formed by the binding portion and the printing portion was larger than 90 °, 135 ° or less, and a slight crack was generated in the hinge portion after repeated bending.
D: The angle between the binding part and the printing part is larger than 135 °. Alternatively, although the angle between the binding portion and the printing portion is 90 ° or less, a crack occurs in the hinge portion after repeated bending.

As shown in the above test results, when the paper thickness P of the printing paper is 250 μm, the ratio of the paper thickness T of the hinge portion to the paper thickness P of the printing paper is in the range of about 10 to 85%, specifically, It was found that the bending performance of the printing paper at the hinge portion becomes a practical level when the value is set to about 38 to 80%. In particular, by setting the same ratio in the range of about 40 to 80%, specifically about 44 to 80%, the hinge portion of the printing paper is given strength to withstand repeated bending, and is in a spread state. The effect of flattening the left and right pages naturally was confirmed. Among them, the effect became more remarkable by setting the same ratio in the range of about 50 to 75%, specifically about 52 to 72%.

As described above, in the present specification, in order to express the content of the present invention, embodiments and examples of the present invention have been described with reference to the drawings. However, the present invention is not limited to the above-described embodiments and examples, and includes modifications and improvements that are obvious to those skilled in the art based on the matters described in the present specification.

The present invention relates to a printing paper having a hinge portion. By using the printing paper according to the present invention, it is possible to produce a booklet (photo album or the like) in which the prints of the left and right pages are seamlessly connected when opened in a spread. Therefore, the present invention can be suitably used in, for example, the printing industry and the paper industry.

10 ... Printing paper 10a, 10b ... Short side 10c, 10d ... Long side 11 ... Hinge part 12 ... Printing part 13 ... Binding part 14 ... Reinforcing part A ... Base material layer B (B1, B2) ... Printing layer

Claims (8)

A printing paper in which a printing layer is laminated on at least one surface of a base material layer which is a thermoplastic resin film including a porous layer.
Printing paper having a linear hinge portion recessed in the thickness direction of the printing paper. The paper thickness in the region other than the hinge portion is 80 to 600 μm.
The printing paper according to claim 1, wherein the paper thickness in the hinge portion is 10 to 85% of the paper thickness in the region other than the hinge portion. The printing paper according to claim 1, wherein the width of the hinge portion is at least twice the depth of the hinge portion. The printing paper according to claim 1, wherein the base material layer is made of a polyolefin-based resin. The printing paper according to claim 1, wherein the porosity of the base material layer in the hinge portion is lower than the porosity of the base material layer in a region other than the hinge portion. The printing paper according to claim 5, wherein the porosity of the base material layer in a region other than the hinge portion is 10 to 45%. The Clark rigidity (S value) in the hinge portion is 10 to 250, and is
The printing paper according to claim 1, wherein the Clark rigidity (S value) in a region other than the hinge portion is 15 to 500. The hinge portion is formed in a straight line parallel to one side of the rectangular printing paper.
The printing paper according to claim 1, wherein a region in which the hinge portion is not formed exists between the other two sides orthogonal to the one side and the hinge portion.

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