JP2011208319A - Production method of embossed paper and embossed paper produced by the production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of embossed paper with which embossed paper, to which embossing processing has been applied, with high design value can be efficiently produced and embossed paper produced by the production method.SOLUTION: A production method of embossed paper includes: the dehydrating step for pressurizing and wet dehydrating paper 50, which contains cellulose fibers and is impregnated with an aqueous liquid, by making the paper 50 pass through a nip part N formed from a pair of press rolls 10, 20; and the drying step for drying the paper 50 having passed through the dehydrating step. As at least one roll 10 of the pair of press rolls 10, 20, an uneven roll is used with which a number of recesses 15 are formed on a roll circumferential surface 10a in contact with the paper 50.

Description

  TECHNICAL FIELD The present invention relates to a method for producing a textured paper having a textured surface for applying an uneven pattern, and a textured paper produced by the production method.

  In general, paper is manufactured through a web forming process, a dehydrating process, and a drying process using a wet paper machine such as a long net type or a circular net type. The wet paper machine is usually a wire part that dehydrates and forms wet paper in the process of transferring a slurry of fiber material dispersed in water through a wire net, and pressurizing while transferring the formed wet paper It comprises a press part that dehydrates by passing between the pair of rolls, and a dryer part that heats and dries the wet paper after dehydration.

  By the way, paper with a smooth surface with no irregularities is usually desired. However, depending on the application, there may be an increase in design or functional value due to irregularities on the surface. There is an intentionally attached paper with a texture.

  With respect to the texture processing, for example, Patent Document 1 discloses, as a surface decoration of a printed matter on paper, an ultraviolet curable undercoat containing a water / oil repellent agent such as a silicone compound and a matting agent having an average particle diameter in a specific range. A technique for partially forming a glossy part and a textured part by applying an ultraviolet curable topcoat liquid over the entire surface of the part where the undercoat liquid has been applied. Are listed. The technique described in Patent Document 1 is to apply a specific liquid to a dried paper and apply a texture pattern. Patent Document 1 does not describe applying a texture pattern to the paper itself.

Japanese Patent No. 3720237

  An object of the present invention is to provide a method for producing a textured paper and a textured paper produced by the production method capable of efficiently producing a textured paper having a high design value that has been subjected to texture processing. .

  The present invention relates to a method for producing a textured paper having a textured surface with a concavo-convex pattern formed thereon, wherein the wet paper containing cellulose fibers and impregnated with an aqueous liquid is formed with a pair of press rolls. A roll having a dehydration step of pressing and dewatering by passing through the formed nip portion, and a drying step of drying the paper that has undergone the dehydration step, and being in contact with the paper as at least one of the pair of press rolls The present invention solves the above problems by providing a method for producing a textured paper using a concavo-convex roll having a large number of recesses on the peripheral surface and a textured paper produced by the production method.

  Further, the present invention is a press roll used in the method for producing a textured paper, comprising a cylindrical roll body, and a sheet-like material wound on a roll peripheral surface of the roll body, the sheet-like material Furthermore, the above-mentioned problems are solved by providing a press roll in which a large number of through-holes that penetrate the sheet-like material in the thickness direction are formed.

According to the present invention, it is possible to efficiently produce a textured paper having a high design value in which a texture is applied to the surface and a concavo-convex pattern is formed in a desired pattern with relatively simple equipment.

FIG. 1 is a schematic perspective view showing an example of a main part of a production apparatus that can be used for carrying out the method for producing a textured paper of the present invention. FIG. 2 is a perspective view showing a partially broken uneven roll (press roll) in the manufacturing apparatus shown in FIG. FIG. 3 is a plan view showing an example of a sheet-like material in the uneven roll shown in FIG. 4 is a cross-sectional view schematically showing a cross section of a nip portion of a pair of press rolls in the manufacturing apparatus shown in FIG. FIG. 5 is a schematic plan view of a textured paper obtained using the sheet-like material shown in FIG.

  Hereinafter, the present invention will be described based on a preferred embodiment thereof with reference to the drawings. The present invention relates to the manufacture of a paper with a texture, which is subjected to a texture processing to give a concavo-convex pattern. In the method for producing a wrinkled paper of the present invention, wrinkles, creases, etc. are intentionally generated (textured) to give a paper with a highly concavo-convex pattern (texture pattern).

  The method for producing a textured paper according to this embodiment includes 1) an impregnation step of impregnating a dry paper with an aqueous liquid to obtain a wet paper, and 2) forming the wet paper obtained in the impregnation step with a pair of press rolls. A dehydration step of pressing and dewatering by passing through the nip portion, and 3) a drying step of drying the wet paper after the dehydration step. FIG. 1 shows the state of the dehydration process.

  In the impregnation step according to this embodiment, a wet paper is obtained by impregnating a dry paper containing cellulose fibers with an aqueous liquid. Cellulose fibers are hydrophilic fibers that have a stable hydrophilic surface and maintain hydrophilicity even after wetting. Examples of cellulose fibers include wood pulp fibers such as softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), and thermomechanical pulp (TMP); Bast fibers; non-wood pulp fibers such as straw, bamboo, kenaf, bagasse; microfibrillated cellulose fibers; biocellulose fibers; rayon fibers; other surface-treated cellulose fibers; carboxylmethylcellulose fibers, etc. Can be used alone or in combination of two or more. The cellulose fiber content is preferably 50% by mass or more, particularly preferably 70 to 100% by mass, based on the total mass of the paper (paper in a dry state before being impregnated with the aqueous liquid).

  The paper used in this embodiment (paper in a dry state before being impregnated with an aqueous liquid) may contain fibers other than the cellulose fibers. Examples of other fibers include recycled fibers such as vinylon, nylon, acrylic, and polyester, synthetic fibers, semi-synthetic fibers, and inorganic fibers such as alumina fibers and alumina silicate fibers. Two or more kinds can be used in combination. The content of other fibers is preferably 50% by mass or less based on the total mass of the paper. If the other fiber exceeds 50% by mass, the paper may be prevented from stretching or shrinking, making it difficult to apply a texture, or causing a disadvantage such as a decrease in the permeability of the aqueous liquid.

  The paper used in this embodiment may contain components other than the fibers described above. Examples of other components include inorganic pigments, organic pigments, paper strength enhancers, yield improvers, water resistance agents, antifoaming agents, and the like that are generally used as raw materials for papermaking and additives. These 1 type can be used individually or in combination of 2 or more types.

The paper used in this embodiment can be produced using a wet paper machine according to a conventional method. The paper used in the present embodiment is preferably a thin one from the viewpoint of enabling strong embossing and obtaining a texture pattern having excellent visibility and high durability. Specifically, the basis weight of the paper used in this embodiment is preferably 70 g / m ² or less, further preferably 30 to 50 g / m ^2. From the same viewpoint, the thickness of the paper used in this embodiment is preferably 150 μm or less, more preferably 50 to 100 μm.

  In addition, as the aqueous liquid used in this embodiment, water may be used, or a solution obtained by dispersing or dissolving various additives in water may be used. Examples of the additive include water-soluble polymers such as starch, polyvinyl alcohol, gelatin, and collagen, and these can be used alone or in combination of two or more.

  When the water-soluble polymer described above is included in the aqueous liquid (that is, the water-soluble polymer is included in the wet paper used in the impregnation step), the bond strength between the constituent fibers of the paper is improved, thereby implementing this embodiment. As a result, the shape stability of the textured paper finally obtained is improved. For this reason, the paper itself becomes stiff when taking up and storing wrinkled paper or stacking paper with wrinkled paper, so the risk of the wrinkle pattern disappearing due to external pressure is reduced. Handleability is improved. The content of the water-soluble polymer is preferably 0.5% by mass or more, more preferably 1 to 5% by mass with respect to the total mass of the aqueous liquid. When the content of the water-soluble polymer exceeds 5% by mass, there is a possibility that inconveniences such as an increase in the viscosity of the aqueous liquid and insufficient impregnation occur.

  In the impregnation step according to the present embodiment, the method for impregnating the dried paper with the aqueous liquid is not particularly limited. In addition to the method of immersing the paper in the aqueous liquid, for example, the method of applying or spraying the aqueous liquid on the paper Etc. The moisture content of the wet paper immediately after the impregnation step (immediately before the dehydration step) is preferably 50 to 200 mass%, more preferably 100 to 150 mass%, from the viewpoint of easy formation of the texture pattern. If the moisture content of the wet paper immediately after the impregnation step is less than 50% by mass, the embossed pattern is difficult to be exhibited due to insufficient moisture, and designability cannot be imparted. Moreover, when the moisture content of the wet paper immediately after the impregnation step exceeds 200% by mass, water is excessive and spreads on the wet paper surface, making it difficult to control the formation of wrinkles.

  In the dehydration process according to this embodiment, as shown in FIG. 1, the wet paper web 50 obtained in the above-described impregnation process is pressurized by passing it through the nip portion N formed by the pair of press rolls 10 and 20. Dehydrate. The wet paper web 50 is a long belt-like sheet, and is transported by being pulled in a direction indicated by X1 in the drawing (longitudinal direction of the belt-like wet paper web 50, MD) by a known sheet transport means (not shown). Passed through. That is, the wet paper web 50 is compressed by the rolls 10 and 20 at the nip portion N in a state where the tension due to conveyance is applied.

  The press rolls 10 and 20 are both cylindrical rolls supported so as to be rotatable around the roll axis, and are arranged side by side with the respective roll peripheral surfaces 10a and 20a facing each other. Either one or both of the roll shafts of both the rolls 10 and 20 are provided with drive means (not shown), and the drive force from the drive means is transmitted so that the rolls 10 and 20 are It is designed to rotate synchronously. Both rolls 10 and 20 each include a metal rigid body such as an aluminum alloy or steel.

  In the present embodiment, of the pair of press rolls 10 and 20, the press roll 10 disposed above the wet paper web 50 being transported has irregularities in which a large number of concave portions 15 are formed on the roll peripheral surface 10a in contact with the paper. The press roll 20 which is a roll and is disposed below the wet paper web 50 being transported is a smooth roll having no irregularities on the roll peripheral surface 20a.

  As shown in FIG. 2, the press roll 10 includes a cylindrical roll body 11 and a sheet-like object 12 wound on the roll peripheral surface 11 a of the roll body 11. The entire roll peripheral surface 11 a of the roll body 11 is covered with the sheet-like object 12. The roll body 11 and the sheet-like object 12 are joined by a known joining means such as an adhesive.

  A large number of through-holes 13 that penetrate the sheet-like material 12 in the thickness direction are formed in the sheet-like material 12. The through hole 13 has a circular shape in plan view. The through-hole 13 in the sheet-like object 12 becomes a recess 15 by winding the sheet-like object 12 on the roll peripheral surface 11 a of the roll body 11. That is, each of the plurality of recesses 15 includes a bottom portion and a side wall portion surrounding the bottom portion, and the bottom portion includes a roll peripheral surface 11 a and the side wall portion includes a sheet-like material 12. The depth of the recess 15 is equal to the thickness of the sheet-like material 12.

  The through-hole 13 is formed by punching a non-porous and flat sheet base material constituting the sheet-like object 12 in the thickness direction. A portion of the sheet-like material 12 where the through hole 13 is not formed is a flat portion 14 without unevenness. As the sheet base material constituting the sheet-like material 12, a water-resistant one is preferably used, for example, a resin film such as polyolefin, polyester, polyethylene terephthalate, polyamide, polyvinyl chloride, polycarbonate, fluororesin; chloroprene rubber, Examples thereof include nitrile rubber, butyl rubber, urethane rubber, silicon rubber, and the like.

  FIG. 3 shows a plan view of the sheet 12. As shown in FIG. 3, the numerous through holes 13 are arranged in a so-called staggered pattern. That is, a large number of through-holes 13 are arranged at predetermined intervals in the circumferential direction X of the roll body 11 to form a through-hole row 13A, and this through-hole row 13A is in the roll axial direction Y (CD In the arbitrary two through-hole rows 13A and 13A that are arranged at predetermined intervals and are adjacent to the CD, the through-holes 13 are not adjacent to the CD. The periphery of each through-hole 13 is a flat plane portion 14 having no irregularities. The plane portion 14 exists in a continuous linear shape in each of the four directions of the circumferential direction X, the roll axis direction Y, and the directions Z1 and Z2 intersecting both directions X and Y, and is a continuous linear plane portion extending in the circumferential direction X. 14A, a continuous linear plane portion 14B extending in the roll axis direction Y (CD), and continuous linear plane portions 14C and 14D extending in the two directions Z1 and Z2 intersecting the two plane portions 14A and 14B, respectively. ing. The arrangement pattern of the through holes 13 (plane portion 14) in the sheet-like article 12 is one of the important elements that influence the arrangement pattern of the embossed pattern on the embossed paper.

  FIG. 4 schematically shows a cross section of a nip portion N (see FIG. 1) formed by both rolls 10 and 20 in the dehydration process. As shown in FIG. 1, when a flat wet paper web 50 is introduced into a nip portion N between both rolls 10 and 20 that rotate in conjunction with each other, the lower surface of the wet paper web 50 is smooth as shown in FIG. 4. In a state in which the roll 20 is in contact with the roll peripheral surface 20a, a portion 51 located below the flat surface portion 14 of the press roll 10 is compressed and crushed by the flat surface portion 14 and the roll peripheral surface 20a. A portion 52 located below is pushed into the recess 15. The pushed-in portion 52 is deformed along the shape in the recess 15 and becomes convex upward.

  As described above, the roll peripheral surface 10a of the press roll 10 that comes into contact with the wet paper web 50 is provided with irregularities including the flat portion 14 and the concave portion 15, and therefore a predetermined nip pressure (linear pressure) at the nip portion N. ), The pressure applied to the wet paper 50 becomes non-uniform, and the pressure applied to the portion 52 corresponding to the concave portion 15 is pushed into the concave portion 15, whereby the flat portion 14. It becomes smaller than the pressure applied to the portion 51 corresponding to. Therefore, the portion 52 of the wet paper 50 passes through the nip portion N in a state where the degree of dehydration is smaller than that of the portion 51 and the moisture content is higher than that of the portion 51.

  In the subsequent drying process, the wet paper 50 that has undergone the dehydration process is heated and forcibly dried by a heating means (not shown) in a state in which tension is applied by conveyance, thereby obtaining a target textured paper. As the heating means, known means can be used without particular limitation, and for example, a Yankee dryer, an air-through dryer, or the like can be used. However, from the viewpoint of reliably forming the texture pattern, at the very initial drying after the dehydration process, at least the portion 52 (convex portion) corresponding to the concave portion 15 of the wet paper web 50 does not contact the heat source body of the drying device. Preferably, the drying apparatus that can perform such drying includes, for example, an air floating dryer. By such drying, the portions 51 and 52 having different moisture contents of the wet paper 50 are shrink-dried while maintaining their shapes as much as possible, and are easily reproduced as desired paper with a texture.

  As described above, since the wet paper 50 is formed with the portions 51 and 52 having different shapes and moisture contents in a predetermined pattern, even when the wet paper 50 is heated and dried at a uniform temperature, The behavior of the constituent components of the wet paper such as fibers at the time of drying is different between the portion 51 and the portion 52. As a result, the paper (wrinkled paper) obtained by drying the wet paper 50 has a predetermined wrinkle or twist. It occurs in a pattern, and these form a highly concavo-convex pattern (texture pattern).

  FIG. 5 is a schematic plan view of the surface 60 facing the press roll 10 of the embossed paper 60 obtained by dehydrating and drying the wet paper 50 using the sheet-like material 12 shown in FIG. The textured paper 60 includes continuous linear groove portions that intersect with each other in a portion corresponding to the portion 51 of the wet paper 50 corresponding to the continuous linear plane portions 14A and 14C and 14D of the press roll 10 described above. 61A (the portion indicated by the straight dotted line in FIG. 5) and the groove portion 61C and the groove portion 61D (the portion indicated by the straight solid line extending obliquely in FIG. 5) are formed so as to be easily visible visually. In the portion corresponding to the portion 52 in the paper 50, the convex portion 62 is formed so as to be easily visible visually. The height difference of the concavo-convex pattern in such a textured paper (the height difference between the bottom of the groove 61A, 61C or 61D and the top of the protrusion 62) is usually 3 mm or less. According to this embodiment, it is possible to efficiently produce such a textured paper having a high design property with relatively simple equipment.

  The formation of the texture pattern is affected not only by the state of the wet paper web 50 (nonuniform moisture content and shape) in the dehydration process described above, but also by the tension during the transport of the wet paper web 50. That is, the embossed paper 60 shown in FIG. 5 should be formed corresponding to the continuous linear plane portion 14B extending in the CD (the direction perpendicular to the transport direction X1 of the paper 60) in the press roll 10. The groove portion (groove portion extending in the left-right direction in FIG. 5, not shown) is not formed so as to be easily visible visually, and the embossing is weak. The reason is that in this embodiment, the tension is applied to the wet paper web 50 in the transport direction X1 in the dehydration process and the drying process, so that the fibers are easily oriented in the transport direction X1, and the CD is orthogonal to the transport direction X1. It is presumed that wrinkles and creases are less likely to occur in the case, and uneven patterns are difficult to form. Therefore, when the dehydration process and the drying process described above are performed so that the wet paper 50 is not tensioned, the textured paper thus obtained corresponds to the continuous linear plane portion 14B, as shown in FIG. Grooves extending in the middle and right and left directions are formed so as to be easily visible.

  From the viewpoint of enabling strong embossing and obtaining a textured paper with high designability, the depth of the recess 15 (thickness of the sheet-like material 12) d (see FIG. 4) is preferably 50 to 1000 μm, more preferably 100-250 μm. From the same viewpoint, the diameter r (see FIG. 3) of the circular recess 15 is preferably 0.5 to 10 mm, more preferably 1 to 5 mm. When the diameter r is less than this range, the work efficiency of circular fabrication is remarkably deteriorated and is not realistic. When the diameter r exceeds this range, water or an aqueous solution flows due to centrifugal force due to the rotation of the press roll 10, It becomes difficult to express the intended design.

  From the same viewpoint, the moisture content of the wet paper web 50 (the portion 51) immediately after the dehydration process (immediately before the drying process) is preferably 50 to 200% by mass, and more preferably 100 to 150% by mass. If the moisture content of the wet paper immediately after the dehydration step is less than 50% by mass, the water texture is insufficient, so that the embossed pattern is difficult to be exhibited, and the designability cannot be imparted. In addition, when the moisture content of the wet paper immediately after the dehydration process exceeds 200% by mass, the moisture is excessive and spreads on the wet paper surface, making it difficult to control the formation of wrinkles.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, the shape of the concave portion 15 is not limited to a circular shape, and can be a desired shape, for example, an elliptical shape, a polygonal shape, a pattern, or the like, and a plurality of types of concave portions having different shapes can be formed. You may combine them. Further, the arrangement pattern of the recesses 15 is not limited to the zigzag pattern as shown in FIG. 3, and can be a desired arrangement pattern so as to obtain a desired texture pattern.

  In the above-described embodiment, the wet paper web 50 may be preliminarily dehydrated by other dehydrating means (for example, another pair of press rolls) before the dehydrating step by the pair of press rolls 10 and 20. Moreover, the press rolls 10 and 20 may be provided with a suction box inside like a suction roll in a normal wet paper machine, so that moisture from the wet paper 50 can be sucked by the suction box.

  Moreover, in the said embodiment, although one roll 10 of a pair of press rolls 10 and 20 was an uneven | corrugated roll, both rolls 10 and 20 are good also as an uneven | corrugated roll, respectively. In that case, a pair of uneven | corrugated rolls 10 and 20 may mutually differ in the arrangement pattern of the recessed part 15, and may differ. When a pair of concave and convex rolls 10 and 20 having the same arrangement pattern of the recesses 15 are used, synchronous rotation is performed so that the flat portions 14 and the recesses 15 of each roll face each other in the nip portion N formed by them. Can be made.

  In addition, the embodiment includes the impregnation step of impregnating the dried paper with the aqueous liquid as the step of obtaining the wet paper 50 prior to the dehydration step. However, the impregnation step may be omitted. By applying the invention to a normal wet papermaking method, the impregnation step can be omitted. In general, wet papermaking consists of a wire part that forms wet paper from a slurry, a press part that dehydrates by passing the formed wet paper through a pair of pressurized rolls, and a wet paper after dehydration. As a roll used in this press part, the concavo-convex roll described above is used, wet papermaking is performed according to a conventional method, and the above-described various conditions are satisfied. High textured paper is obtained. According to the present invention, it is possible to make maximum use of existing wet paper machines as described above, and to efficiently produce textured paper with high design without introducing new large-scale equipment and complicated processes. it can.

  The textured paper obtained by carrying out the present invention is suitable for packaging materials such as clothing, stationery, food, cosmetics, medicine, medical equipment, mechanical parts, electronic equipment, and clothing, etc. by utilizing its high designability. Used for.

10 Concavity and convexity roll (press roll)
10a Roll peripheral surface of uneven roll 11 Roll body 12 Sheet-like material 13 Through-holes 14, 14A, 14B, 14C, 14D Flat portion 15 Recessed portion 20 Smooth roll (press roll)
50 Wet paper 60 Paper with grain 61A, 61C, 61D Groove 62 Projection N Nip

Claims (5)

A method for producing a textured paper, wherein the textured surface with a fine uneven pattern is applied to the surface,
A dehydration step of pressurizing and dehydrating a wet paper containing cellulose fibers and impregnated with an aqueous liquid through a nip formed by a pair of press rolls, and drying the paper after the dehydration step A drying process,
A method for producing a textured paper, wherein as the at least one of the pair of press rolls, a concavo-convex roll having a large number of concave portions formed on a peripheral surface of the roll in contact with the paper.   The method for producing a textured paper according to claim 1, wherein the uneven roll is configured by winding a sheet-like material having a number of through holes penetrating in a thickness direction on a roll peripheral surface of a cylindrical roll body.   The method for producing a textured paper according to claim 1 or 2, wherein the recess has a depth of 50 to 1000 µm. A press roll used in the method for producing a textured paper according to claim 1,
A cylindrical roll body and a sheet-like material wound around the roll peripheral surface of the roll body are provided, and a plurality of through-holes penetrating the sheet-like material in the thickness direction are formed in the sheet-like material. Press roll.   4. A textured paper produced by the method for producing a textured paper according to claim 1.

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