Cushioning paper and paper cushioning

Abstract

To provide cushioning paper capable of obtaining a paper cushioning material excellent mild cushioning property, having sufficient lamination property and perforation retention, and excellent in flexure processability, in addition, to provide a laminated product and paper cushioning material obtained from the cushioning material paper.SOLUTION: This is a cushioning material paper that has multiple perforated sections in a horizontal direction, with the vertical distance between adjacent perforated sections being the same, a basis weight being 50 g / m2 or more and 150 g / m2 or less, and geometric mean of the specific tensile strength in the longitudinal direction excluding the perforated part and the specific tensile strength in the lateral direction excluding the perforated part, measured in accordance with JIS P 8113:2006, is between 17.0 N m / g and 70.0 N m / g, and the tensile strength of the perforated sections in the vertical direction is between 0.5 kN / m or more and 3.0 kN / m or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to cushioning paper and paper cushioning materials.

Background Art

[0002] When storing contents such as products in a case such as a cardboard box for packaging, a cushioning material is used to fill the gap between the case and the contents and to absorb vibrations, impacts, etc. applied to the contents during transportation. As cushioning materials, air caps, air cushions, foam chips, etc. have been used. Air caps and air cushions are formed of a resin such as polyethylene, and a large number of hollow protrusions are formed on the resin sheet. Foam chips are relatively small-sized cushioning materials formed of a foaming resin, and are used by packing them so as to fill the gap between the case and the contents. From the viewpoint of environmental protection, paper cushioning materials (paper cushioning materials) are becoming popular in place of the above-described plastic cushioning materials.

[0003] Patent Document 1 aims to provide a paper cushioning material having the advantages of conventional cushioning materials, that is, being able to be manufactured at low cost, being easily disposable because no harmful gas is generated during incineration disposal, and having versatility because it is amorphous, and further having an excellent cushioning effect. A method for manufacturing a paper cushioning material is disclosed, which comprises supplying a piece of paper into the hollow drum from the slit of the hollow drum in which slits are formed in the axial direction, hooking the tip of the piece of paper on the inner surface of the hollow drum, and further continuing the supply of the piece of paper to fold the piece of paper in a zigzag manner in the hollow drum, and then moving a compression plate movable along the axial direction in the hollow drum to compress and round the piece of paper folded in a zigzag manner in the hollow drum from the end side of the hollow drum.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The method for manufacturing a paper cushioning material described in Patent Document 1 has been studied for the method of manufacturing a paper cushioning material bent from paper pieces, but the cushioning paper itself used for the paper cushioning material has not been studied. An object of the present invention is to provide a cushioning paper for a cushioning material that can obtain a paper cushioning material having excellent cushioning properties, sufficient lamination properties and perforation retention properties, and excellent bending processability. Further, an object of the present invention is to provide a laminate and a paper cushioning material obtained from the cushioning paper. Note that “lamination property” means that when forming a laminate, the displacement of the horizontal positions of the cushioning papers can be suppressed. Further, “bending processability” means the processability when forming a fold by bending the cushioning paper to obtain a paper cushioning material.

Means for Solving the Problems

[0006] The inventors of the present invention have found that the above problems can be solved by setting the basis weight of the cushioning paper within a specific range, making the vertical distance between adjacent perforated portions the same, and further setting the longitudinal specific tensile strength excluding the perforated portion and the transverse specific tensile strength excluding the perforated portion. The geometric mean value, and the tensile strength of the longitudinal perforated portion within a specific range. That is, the present invention relates to the following <1> to <9>. <1> A cushioning paper having a plurality of perforated portions in the transverse direction, wherein the vertical distance between adjacent perforated portions is the same, the basis weight is 50 g / m 2 or more and 150 g / m 2 or less, The geometric mean value of the longitudinal specific tensile strength and the transverse specific tensile strength, excluding the stitch part, measured in accordance with JIS P 8113:2006 is 17.0 Nm / g or more and 70.0 Nm / g or less, A cushioning paper in which the longitudinal tensile strength of the stitch part, measured in accordance with JIS P 8113:2006, is 0.5 kN / m or more and 3.0 kN / m or less. <2> The cushioning paper according to <1>, wherein the length of the tie part of the stitch part is 0.3 mm or more and 3.2 mm or less. <3> The cushioning paper according to <1> or <2>, wherein the tie cut ratio (length of the tie part / length of the cut part) of the stitch part is 0.2 or more and 3.5 or less. <4> The cushioning paper according to any one of <1> to <3>, which contains a dry paper strength enhancer, and the content of the dry paper strength enhancer is 0.05% by mass or more and 2.50% by mass or less. <5> The cushioning paper according to any one of <1> to <4>, wherein the cushioning paper contains waste paper pulp as a raw material pulp. <6> The cushioning paper according to <5>, wherein the content of waste paper pulp in the raw material pulp is 80% by mass or more. <7> The cushioning paper according to any one of <1> to <6>, which has a thickness of 50 μm or more and 250 μm or less. <8> A laminate formed by alternately folding back the cushioning paper according to any one of <1> to <7> with a plurality of stitch parts provided in the transverse direction to form a bellows-like stack. <9> A paper cushioning material formed by bending the cushioning paper according to any one of <1> to <7> or the cushioning paper constituting the laminate according to <8>.

Advantages of the Invention

[0007] According to the present invention, a paper cushioning material excellent in cushioning properties is obtained, and a cushioning paper having sufficient laminating properties and stitch holding properties and excellent in bending processability is provided. Further, according to the present invention, a laminate and a paper cushioning material obtained from the cushioning paper are provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] [Paper for Cushioning Material] The cushioning material paper of the present embodiment has a plurality of perforation portions in the lateral direction, the vertical distance between adjacent perforation portions is the same, and the basis weight is 50 g / m 2 or more and 150 g / m 2 or less, and the geometric mean value of the specific tensile strength in the vertical direction excluding the perforation portion and the specific tensile strength in the lateral direction excluding the perforation portion, measured in accordance with JIS P 8113:2006, is 17.0 Nm / g or more and 70.0 Nm / g or less, and the tensile strength of the vertical perforation portion is 0.5 kN / m or more and 3.0 kN / m or less. According to the present embodiment, a paper cushioning material excellent in cushioning performance can be obtained, and a cushioning material paper having sufficient laminating property and perforation holding property and excellent in bendability is provided. Since the cushioning material paper has sufficient laminating property and perforation holding property, when storing or transporting a laminate obtained by accordion folding the cushioning material paper, it can be boxed without gaps, and the paper can be continuously supplied to a cushioning material manufacturing machine using the laminate, and the load on the cushioning material manufacturing machine can be reduced. The reason for obtaining the above effects is that the basis weight is 50 g / m 2 or more and 150 g / m 2The following is the case. By virtue of the fact that the geometric mean value of the longitudinal specific tensile strength excluding the perforation part and the transverse specific tensile strength excluding the perforation part is 17.0 Nm / g or more and 70.0 Nm / g or less, it is considered that a cushioning material paper excellent in cushioning properties and bendability is obtained. Further, by virtue of the fact that the longitudinal distance between adjacent perforation parts is the same and the tensile strength of the longitudinal perforation part is 0.5 kN / m or more and 3.0 kN / m or less, it is considered that the stacking property is excellent and the perforations can be held when supplied to a cushioning material manufacturing machine. Note that the reason for obtaining the above effects is not limited to this. Further, according to the cushioning material paper of the present embodiment, compared with a cushioning material formed from a conventional plastic, it is formed of paper mainly composed of pulp, and the environmental load is reduced. Hereinafter, the present invention will be described in more detail.

[0010] In this specification, the numerical range represented by "X to Y" means a numerical range including X as the lower limit value and Y as the upper limit value. When the numerical range is described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined. Further, the longitudinal direction of the cushioning material paper means the paper-making direction (MD), and the transverse direction means the direction (CD) orthogonal to the paper-making direction.

[0011] The cushioning material paper of the present embodiment includes a paper base material, and the paper base material includes pulp as a raw material. The manufacturing method and type of pulp are not particularly limited. Note that the cushioning material paper of the present embodiment may include at least a paper base material and may have a coating layer such as a resin layer or a laminate layer, etc., but it is preferably composed only of the paper base material. Further, the paper base material may have a single-layer structure or a multi-layer structure. In the case of multi-layer paper, the number of paper layers is not particularly limited, but for example, it is preferably 2 layers or more and 7 layers or less, more preferably 2 layers or more and 6 layers or less.

[0012] <Raw material pulp> In this embodiment, from the perspective of reducing environmental impact, natural pulp fibers are preferred as the pulp constituting the paper base material. As natural pulp fibers, wood fibers (chemical pulp, mechanical pulp), non-wood fibers, waste paper pulp, etc. can be arbitrarily used as needed. Among the wood fibers, examples of chemical pulp include kraft pulp using caustic soda and sodium sulfide during the cooking of wood chips, and sulfite pulp using sulfurous acid and bisulfite. These pulps may be unbleached or bleached (bleached products). Also, as mechanical pulp, groundwood pulp (GP) obtained by grinding logs with a grinder, refiner groundwood pulp (RGP) obtained by grinding waste materials from a sawmill with a refiner, thermomechanical pulp (TMP) obtained by heating and refining wood chips, etc. can be mentioned. Among these, waste paper pulp, unbleached softwood kraft pulp (NUKP), and unbleached hardwood kraft pulp (LUKP) are preferably used. Also, among these wood fiber pulps, examples of softwood trees used as raw materials for softwood pulp include pine, larch, cedar, fir, and cypress. Also, examples of hardwood trees used as raw materials for hardwood pulp include eucalyptus, acacia, oak, beech, maple, elm, and chestnut.

[0013] Also, examples of non-wood fibers that can be used in this embodiment include bast fibers such as kozo, mitsumata, ganpi, hemp, tilia, kenaf, choma, jute, and sunn hemp, seed hair fibers such as cotton and cotton linter, leaf fibers such as Manila hemp, sisal hemp, and esparto, and stem fibers such as bamboo, rice straw, wheat straw, and sugarcane bagasse. In particular, kozo, mitsumata, kenaf, Manila hemp, sisal hemp, cotton, and cotton linter are preferably used because they have long fiber lengths and can improve the strength of the base paper in this embodiment. The cooking of non-wood fibers can be performed in the same manner as that of wood fibers. Examples of waste paper pulp that can be used in this embodiment include cardboard waste paper and magazine waste paper.

[0014] These pulp fibers can be used alone or in combination of two or more. Further, synthetic resin fibers can be mixed as necessary within a range not impairing the effects of the present invention. Examples of the synthetic resin fibers that can be used include polyethylene fibers, polypropylene fibers, polyamide fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polylactic acid fibers, and the like.

[0015] In the present embodiment, from the viewpoints of obtaining a desired specific tensile strength and tensile strength described later and manufacturing the cushioning paper inexpensively, it is preferable that the raw material pulp contains at least wastepaper pulp, and in addition to the wastepaper pulp, softwood pulp and / or hardwood pulp may be contained. From the viewpoints of obtaining the desired specific tensile strength and tensile strength described later and manufacturing the cushioning paper inexpensively, the content of wastepaper pulp in the raw material pulp is preferably 80% by mass or more and 100% by mass or less, more preferably 85% by mass or more, still more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0016] <Optional component> The paper base material may contain, as necessary, for example, internal additives such as anionic, cationic, nonionic or amphoteric retention aids, drainage improvers, dry paper strength enhancers, wet paper strength enhancers, fillers, fixing agents (sulfate bands), sizing agents, etc., and optional components such as dyes and fluorescent brighteners, and preferably contains a dry paper strength enhancer. Examples of the dry paper strength enhancer include cationized starch, polyacrylamide, carboxymethyl cellulose, and the like. Among these, from the viewpoint of obtaining the desired specific tensile strength and tensile strength described later, a polyacrylamide-based dry paper strength enhancer is preferable. When the cushioning paper of the present embodiment contains a dry paper strength enhancer, the content of the dry paper strength enhancer is preferably 0.05% by mass or more and 2.50% by mass or less, more preferably 0.20% by mass or more, still more preferably 0.40% by mass or more, and then more preferably 1.90% by mass or less, still more preferably 1.30% by mass or less, and even more preferably 1.10% by mass or less from the viewpoints of obtaining the desired specific tensile strength and tensile strength described later.

[0017] Examples of the wet strength agent include polyamide polyamine epichlorohydrin, urea formaldehyde resin, melamine formaldehyde resin, and the like. Examples of the filler include inorganic fillers such as talc, kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, white carbon, bentonite, zeolite, sericite, and smectite, and organic fillers such as acrylic resins and vinylidene chloride resins. When the cushioning material paper of the present embodiment contains a wet strength agent, the content of the wet strength agent is preferably 0.01 part by mass or more and 3 parts by mass or less, more preferably 0.05 part by mass or more, still more preferably 0.1 part by mass or more, and more preferably 1.5 parts by mass or less, still more preferably 0.5 part by mass or less, based on 100 parts by mass of the raw material pulp. Note that the cushioning material paper of the present embodiment preferably does not contain a wet strength agent.

[0018] Examples of the sizing agent include internal sizing agents such as rosin sizing agents, synthetic sizing agents, and petroleum resin-based sizing agents, and surface sizing agents such as styrene / acrylic acid copolymers and styrene / methacrylic acid copolymers. When the cushioning material paper of the present embodiment contains a sizing agent, the content of the sizing agent is preferably 0.01 part by mass or more and 3 parts by mass or less, more preferably 0.05 part by mass or more, still more preferably 0.1 part by mass or more, and more preferably 1.5 parts by mass or less, still more preferably 0.5 part by mass or less, based on 100 parts by mass of the raw material pulp. Note that the cushioning material paper of the present embodiment preferably does not contain a sizing agent.

[0019] When the cushioning paper of the present embodiment contains a fixing agent, the content of the fixing agent is preferably 0.01 part by mass or more and 5 parts by mass or less, more preferably 0.1 part by mass or more, still more preferably 0.5 part by mass or more, and more preferably 3 parts by mass or less, still more preferably 1.5 parts by mass or less, based on 100 parts by mass of the raw material pulp.

[0020] <Method for manufacturing cushioning paper> The method for manufacturing cushioning paper preferably includes a step of forming a slurry containing the above raw material pulp into a sheet to obtain a cushioning base paper, and a step of perforating the cushioning base paper to obtain cushioning paper. The papermaking method is not particularly limited, and examples thereof include an acidic papermaking method in which papermaking is performed at a pH of around 4.5, a neutral papermaking method in which papermaking is performed at a pH of about 6 to about 9, and the like. In the papermaking step, if necessary, papermaking chemicals such as a pH adjuster, an antifoaming agent, a pitch control agent, and a slime control agent can be appropriately added. The paper machine is also not particularly limited, and examples thereof include a Fourdrinier machine, a cylinder machine, an inclined machine, and other continuous paper machines, or a multi-layer combined paper machine combining these.

[0021] In the present embodiment, in the papermaking step, the jet / wire ratio (J / W ratio), which is the ratio of the flow rate (J) of the stock ejected onto the wire to the running speed (W) of the papermaking wire, can be appropriately adjusted from the viewpoint of making the ratio (tensile strength in the longitudinal direction without perforations / tensile strength in the transverse direction without perforations) of the longitudinal specific tensile strength without the perforation part and the transverse specific tensile strength without the perforation part fall within a desired range.

[0022] Further, after papermaking, a coating step of applying a coating liquid containing at least one selected from the group consisting of a water-soluble resin and a water-suspensible resin on at least one surface may be included. The surface layer is formed by the above coating step. As the coating device, a size press machine or the like can be used.

[0023] The buffer material paper of the present embodiment can be obtained by performing perforation processing on the buffer material base paper obtained through the above papermaking process and, if necessary, the above coating process to form perforated portions. The perforation processing step can be carried out by a conventional method using, for example, a commercially available perforation processing machine. Examples of commercially available perforation processing machines include a business form rotary printing machine (MVF-18B manufactured by Miyakoshi), an automatic sewing machine (VP-66A manufactured by Horizon Japan), and a paperboard ruling device (E-888 manufactured by Nippon T.M.C.).

[0024] <Properties of the buffer material paper> (Grammage) From the viewpoints of cushioning properties and bendability when making a paper buffer material, the grammage of the buffer material paper is 50 g / m 2 or more and 150 g / m 2 or less. From the viewpoint of cushioning properties, the grammage of the buffer material paper is preferably 55 g / m 2 or more, and from the viewpoint of bendability when making a paper buffer material, it is preferably 135 g / m 2 or less, more preferably 110 g / m 2 or less, still more preferably 90 g / m 2 or less. The grammage of the buffer material paper is measured in accordance with JIS P 8124:2011. Specifically, it is measured by the method described in the examples.

[0025] (Thickness) From the viewpoints of cushioning properties and bendability when making a paper buffer material, the thickness of the buffer material paper is preferably 50 μm or more and 250 μm or less. From the viewpoint of cushioning properties, it is more preferably 65 μm or more, still more preferably 80 μm or more, even more preferably 95 μm or more, and still more preferably 110 μm or more. And from the viewpoint of bendability when making a paper buffer material, it is more preferably 220 μm or less, still more preferably 170 μm or less, and even more preferably 140 μm or less. The thickness of the buffer material paper is measured in accordance with JIS P 8118:2014, and specifically, it is measured by the method described in the examples.

[0026] (Density) From the viewpoints of cushioning performance and bendability when forming a paper cushioning material, the density of the cushioning paper of this embodiment is preferably 0.40 g / cm 3 or more and 0.90 g / cm 3 or less. Generally, for the same basis weight, a lower density results in a paper cushioning material with better cushioning performance. The density of the cushioning paper is more preferably 0.45 g / cm 3 or more, even more preferably 0.50 g / cm 3 or more, and still more preferably 0.55 g / cm 3 or more, and is more preferably 0.85 g / cm 3 or less, even more preferably 0.80 g / cm 3 or less, still more preferably 0.75 g / cm 3 or less, and even more preferably 0.70 g / cm 3 or less. The density of the cushioning paper can be appropriately adjusted by adjusting the press pressure in the papermaking process. Also, the density of the cushioning paper is calculated from the thickness and basis weight of the cushioning paper.

[0027] (Specific tensile strength) For the cushioning paper of this embodiment, the geometric mean value of the specific tensile strength in the longitudinal direction (excluding the perforation part) and the specific tensile strength in the transverse direction (excluding the perforation part), measured in accordance with JIS P 8113:2006, is 17.0 Nm / g or more and 70.0 Nm / g or less. When the geometric mean value is 17.0 Nm / g or more, it is preferable because of excellent cushioning performance. When the geometric mean value is 70.0 Nm / g or less, it is preferable because of excellent bendability when forming a paper cushioning material. Also, from the viewpoint of cushioning performance, the geometric mean value is preferably 20.0 Nm / g or more, more preferably 23.0 Nm / g or more, and even more preferably 26.0 Nm / g or more. From the viewpoint of bendability when forming a paper cushioning material, the geometric mean value is preferably 50.0 Nm / g or less, more preferably 45.0 Nm / g or less, and even more preferably 40.0 Nm / g or less. The longitudinal tensile strength of the buffer paper excluding the perforation part and the transverse tensile strength of the buffer paper excluding the perforation part are measured in accordance with JIS P 8113:2006 for a test paper without a perforation part obtained by separating the buffer paper with two adjacent perforations, and the product mean of the value obtained by dividing the longitudinal tensile strength by the basis weight (longitudinal specific tensile strength) and the value obtained by dividing the transverse tensile strength by the basis weight (transverse specific tensile strength) is calculated. Specifically, it is measured and calculated by the method described in the examples. The specific tensile strength can be adjusted to a desired range according to the type of raw material pulp, the blending ratio, the blending amount of a paper strengthening agent (dry paper strength enhancer), the density of the buffer paper, etc. When using waste paper pulp as the raw material pulp, when the blending amount of the paper strengthening agent is increased, the specific tensile strength tends to increase. Also, when using waste paper pulp, NUKP and LUKP, when the ratio of NUKP is increased, the specific tensile strength tends to increase.

[0028] The ratio of the longitudinal tensile strength of the buffer paper excluding the perforation part to the transverse tensile strength of the buffer paper excluding the perforation part (longitudinal tensile strength of the buffer paper excluding the perforation part / transverse tensile strength of the buffer paper excluding the perforation part) (hereinafter also referred to as the aspect ratio of the specific tensile strength) is preferably 1.0 or more and 5.5 or less. When the aspect ratio of the specific tensile strength is 1.0 or more, it is preferable because the bending processability is excellent. Also, when the aspect ratio of the specific tensile strength is 5.5 or less, it is preferable because the cushioning property is excellent. The aspect ratio of the specific tensile strength is more preferably 1.5 or more, still more preferably 1.8 or more, and more preferably 4.0 or less, still more preferably 3.0 or less. The aspect ratio of the specific tensile strength can be appropriately adjusted by adjusting the J / W ratio in the papermaking process.

[0029] (Tensile strength) The buffer material paper of this embodiment has a longitudinal tensile strength of 0.5 kN / m or more and 3.0 kN / m or less at the perforation part, which is measured in accordance with JIS P 8113:2006. From the perspective of perforation retention, the tensile strength of the buffer material paper of this embodiment is 0.5 kN / m or more. When the tensile strength is 0.5 kN / m or more, it is preferable because it is possible to suppress the breakage of the perforations and continuously supply the buffer material paper to the buffer material manufacturing machine using the laminate obtained by accordion folding the buffer material paper. From the perspective of lamination properties, the tensile strength of the buffer material paper of this embodiment is 3.0 kN / m or less. When the tensile strength is 3.0 kN / m or less, it is preferable because it is possible to suppress the displacement of the buffer material paper when manufacturing the laminate. The tensile strength is preferably 0.7 kN / m or more, more preferably 0.9 kN / m or more, still more preferably 1.1 kN / m or more, even more preferably 1.3 kN / m or more, and preferably 2.7 kN / m or less, more preferably 2.4 kN / m or less, still more preferably 2.1 kN / m or less, even more preferably 1.8 kN / m or less, and even more preferably 1.5 kN / m or less. The longitudinal tensile strength of the perforation part of the buffer material paper is measured in accordance with JIS P 8113:2006, and specifically, it is measured and determined by the method described in the examples. The tensile strength can be adjusted to a desired range by factors such as the type of raw material pulp, the blending ratio, the blending amount of paper strength agent (dry paper strength enhancer), the density of the buffer material paper, and the tie cut ratio (length of the tie part / length of the cut part) of the perforation part. When using waste paper pulp as the raw material pulp, increasing the blending amount of the paper strength agent tends to increase the tensile strength. Also, increasing the tie cut ratio tends to increase the tensile strength.

[0030] (Interval between perforation parts) The buffer material paper (reference numeral 10 in FIG. 1) of this embodiment has a plurality of perforation parts (reference numeral 1 in FIG. 1) in the lateral direction, and the longitudinal distance between adjacent perforation parts is the same. From the perspective of lamination properties, the plurality of perforation parts are preferably parallel. "The vertical distance between adjacent stitch portions being the same" means that the difference between the maximum value and the minimum value of the distances between adjacent stitch portions is 10% or less of the maximum value, preferably 5% or less, more preferably 1% or less, and even more preferably 0.5% or less. For example, in the cushioning material paper shown in FIG. 1, when the maximum value of the distances between adjacent stitch portions is 200 mm and the minimum value is 180 mm, the vertical distances between adjacent stitch portions are the same. Also, "a plurality of stitch portions being parallel" means that the angles formed by two stitch portions are all 5 degrees or less, preferably 3 degrees or less, and more preferably 1 degree or less. The interval of the stitch portions can be appropriately selected according to the size of the laminate, the size of the cushioning material paper that can be supplied to the cushioning material manufacturing machine, the shape of the paper cushioning material, etc. The interval of the stitch portions is, for example, 100 mm or more and 500 mm or less.

[0031] (Length of the tie portion) The length of the tie portion of the stitch portion (the length of each connecting portion) is preferably 0.3 mm or more and 3.2 mm or less, more preferably 0.6 mm or more, even more preferably 0.9 mm or more, and even more preferably 1.2 mm or more, and then, more preferably 2.7 mm or less, even more preferably 2.4 mm or less, even more preferably 2.1 mm or less, and still more preferably 1.8 mm or less. From the viewpoint of stitch holding property, it is preferable that the length of the tie portion of the stitch portion is equal to or more than the lower limit, and from the viewpoint of laminating property, it is preferable that the length of the tie portion of the stitch portion is equal to or less than the upper limit.

[0032] (Length of the cut portion) The length of the cut portion at the stitch portion (the length of each cut line portion (each solid line portion of reference numeral 1 in FIG. 1)) is preferably 0.3 mm or more and 5.2 mm or less, more preferably 0.6 mm or more, still more preferably 0.9 mm or more, even more preferably 1.2 mm or more, and more preferably 4.4 mm or less, still more preferably 3.8 mm or less, even more preferably 3.2 mm or less, still more preferably 2.7 mm or less, even more preferably 2.4 mm or less, still more preferably 2.1 mm or less, and particularly preferably 1.8 mm or less. From the viewpoint of stitch retention, it is preferable that the length of the tight portion at the stitch portion is equal to or greater than the lower limit, and from the viewpoint of lamination, it is preferable that the length of the tight portion at the stitch portion is equal to or less than the upper limit.

[0033] (Tight cut ratio) The tight cut ratio of the stitch portion (length of the tight portion / length of the cut portion) is preferably 0.2 or more and 3.5 or less, more preferably 0.4 or more, still more preferably 0.6 or more, even more preferably 0.8 or more, and more preferably 3.1 or less, still more preferably 2.7 or less, even more preferably 2.3 or less, still more preferably 1.9 or less, even more preferably 1.5 or less, and still more preferably 1.2 or less. From the viewpoint of stitch retention, it is preferable that the tight cut ratio of the stitch portion is equal to or greater than the lower limit, and from the viewpoint of lamination, it is preferable that the tight cut ratio of the stitch portion is equal to or less than the upper limit.

[0034] [Laminate] From a practical viewpoint such as storage, transportation, and continuously supplying paper to a buffer material manufacturing machine, it is preferable to form a laminate (reference numeral 20 in FIG. 2) by alternately folding back the buffer material paper at a plurality of stitch portions provided in the lateral direction to form a bellows shape. As shown in FIG. 2, the laminate 20 is formed by alternately folding back the buffer material paper 10 at the stitch portions 1 to form a bellows shape. The stitch portions are preferably provided in the CD direction of the buffer material paper. Note that the number of laminated sheets (number of stitch portions + 1) can be, for example, 30 or more and 1000 or less.

[0035] [Paper buffer material] The paper buffer material of this embodiment is formed by folding the buffer paper of this embodiment or the buffer paper constituting the laminate of this embodiment. The folding process is preferably performed along the MD direction (perpendicular to the CD direction) of the buffer paper so that creases are formed. As another aspect, the buffer paper may be subjected to uneven processing to form a paper buffer material, or it may be further folded to form a paper buffer material. When performing uneven processing, it is preferable to improve the elongation performance by performing a Kurapak process (a process of finely shrinking the paper in the longitudinal direction on a paper machine) or the like on the buffer paper. The folding of the buffer paper may be performed manually by a person, or may be performed manually or electrically by a buffer material manufacturing machine, and is not particularly limited. Even when the buffer paper is folded by an electric buffer material manufacturing machine to produce a paper buffer material, if a buffer paper with poor foldability is used, the load on the machine tends to increase, and problems such as the buffer paper getting clogged or torn may occur. Examples of commercially available buffer material manufacturing machines include the X-FILL series manufactured by Nuevopak, the X-PAD series manufactured by Nuevopak, the Padpak series manufactured by Ranpak, the FillPak series manufactured by Ranpak, the PAPERplus series manufactured by Storopack, the ProPad series manufactured by Sealed Air, the FasFill series manufactured by Sealed Air, and the like. Note that the shape of the buffer paper may be in the form of a roll or a single sheet in addition to the above-mentioned laminate. The paper buffer material of this embodiment is preferably used to fill the gap between a case such as a corrugated cardboard case for packaging and the contents such as goods, and thereby, it is preferably used to absorb vibrations, impacts, etc. applied to the contents during transportation.

Example

[0036] The features of the present invention will be described more specifically by way of Examples and Comparative Examples below. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following Examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0037] [Evaluation and Analysis] The following evaluations and analyses were performed on the cushioning paper and paper cushioning materials of the Examples and Comparative Examples.

[0038] [Cushioning Paper] [Content of Dry Paper Strength Enhancer] The cushioning base paper was cut into pieces with a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain cushioning paper. The perforation process was carried out in the same manner as the <Tensile Strength> described below. Approximately 150 μg of a sample was taken from the cushioning paper, and the content of the polyacrylamide-based internal paper strength enhancer contained in the cushioning paper was determined by mass spectrometry using a pyrolysis GC / MS analyzer (GC8890 / MSD5977B manufactured by Agilent Technologies).

[0039] [Grammage] The cushioning base paper was cut into pieces with a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain cushioning paper. The perforation process was carried out in the same manner as the <Tensile Strength> described below. The cushioning paper was conditioned for 24 hours in a humidity conditioning environment specified in JIS P 8111:1998. In accordance with JIS P 8124:2011, the grammage of the conditioned cushioning paper was measured.

[0040] [Thickness] The cushioning base paper was cut into pieces with a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain cushioning paper. The perforation process was carried out in the same manner as the <Tensile Strength> described below. The cushioning paper was conditioned for 24 hours in a humidity conditioning environment specified in JIS P 8111:1998. In accordance with JIS P 8118:2014, the thickness of the cushioning material paper after conditioning was measured.

[0041] <Density> From the measured basis weight and thickness, the density was calculated using the formula: basis weight (g / m 2 )÷thickness (μm).

[0042] <Specific tensile strength> The cushioning material base paper was cut into a length of 140,000 mm and a width of 380 mm. At intervals of 280 mm in the MD direction, perforations were made in the CD direction to obtain the cushioning material paper. The perforation process was carried out in the same manner as the <Tensile strength> described below. Two adjacent perforations were randomly selected to cut the cushioning material paper, and the paper without perforations was used as the test paper. Five test papers were prepared. After conditioning the test paper for 24 hours in the conditioning environment specified in JIS P 8111:1998, the tensile strength of the conditioned test paper was measured in accordance with JIS P 8113:2006. The tensile strengths in the MD direction and the CD direction were measured. The test was conducted using a horizontal tensile testing machine (manufactured by Lorentzen & Wattre, CODE SE - 064). The specific tensile strength was calculated by dividing the obtained tensile strength (the average value of the tensile strengths of five test pieces) by the basis weight.

[0043] <Tensile strength> The cushioning material base paper was cut into a length of 140,000 mm and a width of 380 mm. At intervals of 280 mm in the MD direction, perforation processing was carried out in the CD direction to obtain the cushioning material paper. The perforation processing was carried out by pressing with a business form rotary printing machine (manufactured by Miyakoshi, MVF - 18B) equipped with a perforating blade under the cutting conditions in Table 1 so that the line pressure was 9.5 mm / N. After conditioning the cushioning material paper for 24 hours in the conditioning environment specified in JIS P 8111:1998, the tensile strength of the conditioned cushioning material paper in the MD direction was measured in accordance with JIS P 8113:2006. In addition, a sample that was manually folded and then unfolded once along a randomly selected stitch was placed so that the stitch would be at the center of the measuring jig. The test was conducted using a horizontal tensile testing machine (manufactured by Lorentzen & Wattre, CODE SE-064). Similarly, measurements were taken for a total of five stitches, and the average value was used as the tensile strength of the buffer material paper in the MD direction.

[0044] <Laminability> The buffer material base paper was cut into a length of 140,000 mm and a width of 380 mm, and stitches were made in the CD direction at intervals of 280 mm in the MD direction to obtain buffer material paper. The buffer material paper was pleated to obtain a laminate. The stitch processing and the pleating were performed using a business form rotary printing machine (MVF-18B manufactured by Miyakoshi). The stitch cutting conditions of the sewing blade used for the stitch processing were as shown in Table 1, and the line pressure was 9.5 N / mm. The state of the folded part and the deviation of the buffer material paper constituting the laminate were observed and evaluated according to the following criteria. If the evaluation is A to C, there is no practical problem. Note that the deviation indicates the maximum difference in the position of the sides of the top and bottom papers. Regarding the "deviation", a supplementary explanation will be given taking the buffer material paper shown in Fig. 1 as an example. The buffer material paper shown in Fig. 1 is buffer material paper with stitches made in the CD direction at intervals of 280 mm in the MD direction and a width of 380 mm. Assuming that a laminate was produced using the buffer material paper shown in Fig. 1 (the number of stitch parts is, for example, 35), the "deviation" is the larger of the distances in the MD direction between measurement points 3a and 3c and the distances in the MD direction between measurement points 3b and 3d. A: No folding is observed in the non-stitch part, and the deviation is less than 5 mm B: No folding is observed in the non-stitch part, and the deviation is 5 mm or more and less than 10 mm C: No folding is observed in the non-stitch part, and the deviation is 10 mm or more and less than 15 mm D: Folding is observed in the non-stitch part, or no folding is observed in the non-stitch part, and the deviation is 15 mm or more

[0045] <Stitch retention> The base paper for the cushioning material was cut into a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain the cushioning material paper. The cushioning material paper was folded in a bellows shape to obtain a laminate. The perforation process and the bellows folding process were performed using a business form rotary printing machine (MVF-18B manufactured by Miyakoshi). The die-cutting conditions of the perforation blade used in the perforation process were as shown in Table 1, and the line pressure was 9.5 N / mm. The above laminate was installed in a cushioning material automatic manufacturing machine (manufactured by NUEVOPAK, X-FILLTMA type), and when it was fed out at a speed of 100 m / min, the frequency of breakage at the perforated part was evaluated according to the following criteria. If the evaluation is A to C, there is no practical problem. The frequency of breakage at the perforated part was counted as the number of perforated parts where breakage occurred among the perforated parts (total number 499) where perforation processing was performed in the CD direction, and was calculated by the following formula. Frequency of breakage at the perforated part (%) = 100 × Number of perforated parts where breakage occurred / Total number of perforated parts (499) A: Frequency of breakage at the perforated part is less than 0.3% B: Frequency of breakage at the perforated part is 0.3% or more and less than 1.0% C: Frequency of breakage at the perforated part is 1.0% or more and less than 2.0% D: Frequency of breakage at the perforated part is 2.0% or more

[0046] <Bending processability> The bending processability is the running and feeding stability in the bending process of the cushioning material manufacturing machine. In the examples, for simulation of practical production, evaluation was carried out by the following method using a laboratory machine. The base paper for the cushioning material was cut into a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain the cushioning material paper. The cushioning material paper was folded in a bellows shape to obtain a laminate. The tip part (about 5 cm) in the MD direction of this laminate was alternately folded back at intervals of 3 cm in the width direction to form a herringbone shape, and it was passed through the folding part of a manual paper cushioning material manufacturing machine (manufactured by NUEVOPAK, X-FILL TM MM type). Next, the manual paper buffer material manufacturing machine was installed under the tensile universal material testing machine (manufactured by A&D, model RTI1310) as shown in Figure 3. At this time, the discharge port of the manual paper buffer material manufacturing machine was set at an angle of 45°C from the test bench of the tensile universal material testing machine, with the height at the lower end of the upper chuck of the tensile universal material testing machine and the center of the discharge port being aligned, and the horizontal center of the discharge port and the center of the upper chuck being aligned. Finally, the harisen-shaped buffer material protruding from the discharge port was grasped by the upper chuck and pulled up at a speed of 1000 mm / min. The load when passing through the bending processing part was measured, and the bending processability was evaluated according to the following criteria based on the average value of 5 test times. If the evaluation is A - C, there is no practical problem. Note that the greater the load when passing through the processing part, the stronger the resistance during processing, which means that in practical use, paper jams are likely to occur, the running performance becomes unstable, and it is difficult to increase the processing speed. A: The average value of the maximum load is less than 8.0 N B: The average value of the maximum load is 8.0 N or more and less than 17.0 N C: The average value of the maximum load is 17.0 N or more and less than 22.0 N D: The average value of the maximum load is 22.0 N or more

[0047] 〔Buffer Material〕 <Shock Absorbing Property> The base paper for the buffer material was cut into a length of 140,000 mm and a width of 380 mm, and perforations were made in the CD direction at intervals of 280 mm in the MD direction to obtain the buffer material paper. The buffer material paper was pleated to obtain a laminate. This laminate was installed in an automatic paper buffer material manufacturing machine (manufactured by PACWELL, model NUEVOPAK TM X-FILL TM Type A), fed out at a speed of 100 m / min, and a paper buffer material with a length of 90 cm was obtained. Next, a 22.5 cm long × 18 cm wide × 10 cm high enclosure was placed on the concrete floor, and the obtained paper buffer material was folded every 22.5 cm and installed in a bellows shape to cover the bottom surface inside the enclosure (Figure 4). Subsequently, the beverage contained in the plastic container (manufactured by Yakult Honsha Co., Ltd., product name: New Yakult, 65 mL) was repeatedly vertically and freely dropped from a height of 40 cm with the bottom facing vertically downward onto the cushioning material within the above enclosure, and the number of times required until deformation such as dents or scratches occurred on the container was counted. The test was conducted 5 times each, and the cushioning performance was evaluated according to the following criteria based on the average number of drops (rounded to the first decimal place) until deformation occurred. If the evaluation is A or B, there is no practical problem. A: The average number of drops is 8 or more B: The average number of drops is 4 or more and less than 8 C: The average number of drops is less than 4

[0048] [Example 1] As a pulp raw material, a pulp slurry of waste paper (corrugated waste paper: magazine waste paper = 85:15 (mass ratio)) pulp was obtained. To 100 parts by mass of pulp (in terms of solid content), 0.40 part by mass (in terms of solid content) of a polyacrylamide-based internal paper strength enhancer (PS117, manufactured by Arakawa Chemical Industries, Ltd.) as an internal paper strength enhancer and 1.2 parts by mass (in terms of solid content) of aluminum sulfate were added to prepare a paper stock. Using this paper stock, a cushioning material base paper was obtained by papermaking using a three-layer long wire papermaking machine with a set basis weight of 80 g / m 2 At this time, the set basis weight of each layer was 22 g / m for the surface layer 2 , 23 g / m for the middle layer 2 , and 35 g / m for the back layer 2 . The cushioning material base paper was cut and perforated as described in the above [Evaluation and Analysis] to obtain a cushioning material paper.

[0049] [Example 2] A cushioning material base paper was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 0.70 part by mass (in terms of solid content). The cushioning material base paper was cut and perforated as described in the above [Evaluation and Analysis] to obtain a cushioning material paper.

[0050] [Example 3] A cushioning material base paper was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 1.30 part by mass (in terms of solid content). The cushioning material base paper was cut and perforated as described in the above [Evaluation and Analysis] to obtain a cushioning material paper.

[0051] [Example 4] A base paper for a cushioning material was obtained under the same conditions as in Example 1, except that 1.20 parts by mass (in terms of solid content) of an internal paper strength enhancer was used. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0052] [Example 5] A base paper for a cushioning material was obtained under the same conditions as in Example 1, except that 0.30 parts by mass (in terms of solid content) of an internal paper strength enhancer was used. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0053] [Example 6] A base paper for a cushioning material was obtained under the same conditions as in Example 2. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0054] [Example 7] A base paper for a cushioning material was obtained under the same conditions as in Example 2. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0055] [Example 8] An internal paper strength enhancer was 1.00 parts by mass (in terms of solid content), and a set basis weight was 60 g / m 2 (surface layer 17 g / m 2 , middle layer 17 g / m 2 , back layer 26 g / m 2 ). A base paper for a cushioning material was obtained under the same conditions as in Example 1. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0056] [Example 9] An internal paper strength enhancer was 0.10 parts by mass (in terms of solid content), and a set basis weight was 130 g / m 2 (surface layer 36 g / m 2 , middle layer 37 g / m 2 , back layer 57 g / m 2A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that [conditions]. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0057] [Example 10] A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 2.80 parts by mass (in terms of solid content). The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0058] [Comparative Example 1] A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 0.20 parts by mass (in terms of solid content). The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0059] [Comparative Example 2] A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 2.80 parts by mass (in terms of solid content). The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0060] [Comparative Example 3] The internal paper strength enhancer was 1.20 parts by mass (in terms of solid content), and the set basis weight was 40 g / m 2 (surface layer 11 g / m 2 , middle layer 12 g / m 2 , back layer 17 g / m 2 ). A base paper for a cushioning material was obtained under the same conditions as in Example 1. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for the cushioning material.

[0061] [Comparative Example 4] The internal paper strength enhancer was 0.10 parts by mass (in terms of solid content), and the set basis weight was 160 g / m 2 (surface layer 44 g / m 2 , middle layer 46 g / m 2 , back layer 70 g / m 2A base paper for a cushioning material was obtained under the same conditions as in Example 1 except as described. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for a cushioning material.

[0062] [Comparative Example 5] A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that no internal paper strength enhancer was added. Note that the "0.02 mass%" in Table 1 is derived from the dry paper strength enhancer derived from the raw material pulp. The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for a cushioning material.

[0063] [Comparative Example 6] A base paper for a cushioning material was obtained under the same conditions as in Example 1 except that the internal paper strength enhancer was 3.50 parts by mass (in terms of solid content). The base paper for the cushioning material was cut and perforated as described in the above [Evaluation and Analysis] to obtain a paper for a cushioning material.

[0064] The above-described evaluation was performed on the obtained paper for a cushioning material. The results are shown in the following table.

[0065]

Table 1

[0066] From the results of the examples and comparative examples, it can be seen that the paper for a cushioning material of the present invention can obtain a paper cushioning material having excellent cushioning properties, has sufficient lamination properties and perforation retention properties, and is excellent in bendability.

Industrial Applicability

[0067] The paper for a cushioning material of the present invention can obtain a paper cushioning material having excellent cushioning properties, has sufficient lamination properties and perforation retention properties, and is excellent in bendability. In particular, it is excellent in bendability and can obtain a paper cushioning material having excellent cushioning properties. Therefore, it is suitably used for paper cushioning materials.

Explanation of Signs

[0068] 1 Perforated part The uppermost surface when it is a laminate 2a The lowermost surface when it is a laminate 2b Measurement points for laminate property evaluation 3a, 3b, 3c, 3d Paper for cushioning material 10 Laminate 20

Claims

1. A buffer material paper having a plurality of perforated portions in the horizontal direction, wherein the vertical distance between adjacent perforated portions is the same, The basis weight is 50 g / m ２ or more and 150 g / m ２ or less, and the geometric mean value of the longitudinal specific tensile strength excluding the perforated portion and the transverse specific tensile strength excluding the perforated portion, measured in accordance with JIS P 8113:2006, is 17.0 Nm / g or more and 70.0 Nm / g or less, and the longitudinal tensile strength of the perforated portion, measured in accordance with JIS P 8113:2006, is 0.5 kN / m or more and 3.0 kN / m or less. A buffer material paper.

2. The buffer material paper according to claim 1, wherein the length of the tie portion of the perforated portion is 0.3 mm or more and 3.2 mm or less.

3. The buffer material paper according to claim 1, wherein the tie cut ratio (length of the tie portion / length of the cut portion) of the perforated portion is 0.2 or more and 3.5 or less.

4. The buffer material paper according to claim 1, which contains a dry paper strength enhancer, and the content of the dry paper strength enhancer is 0.05% by mass or more and 2.50% by mass or less.

5. The buffer material paper according to claim 1, wherein the buffer material paper contains waste paper pulp as a raw material pulp.

6. The buffer material paper according to claim 5, wherein the content of the waste paper pulp in the raw material pulp is 80% by mass or more.

7. The buffer material paper according to claim 1, having a thickness of 50 μm or more and 250 μm or less.

8. A laminate formed by alternately folding back the buffer material paper according to claim 1 with a plurality of perforated portions provided in the horizontal direction and laminating them in a bellows shape.

9. A paper buffer formed by bending the buffer material paper according to any one of claims 1 to 7 or the buffer material paper constituting the laminate according to claim 8.

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