Paper wiper

Abstract

To provide a wiper having high water absorbability and excellent usability, being tough and generating little dust.SOLUTION: A 3-ply paper wiper 1 is formed by superposing three pieces of base paper 11, 12 and 13, and the paper wiper 1 is embossed 20. The paper wiper 1 is so configured that a basis weight of the total of 3 plies of the paper wiper 1 is 56.0 g / m2 or greater and 80.0 g / m2 or less, the paper thickness of the total of 3 plies of the paper wiper 1 is 0.40 mm or greater and 0.62 mm or less, the vertical strength in a dry condition of the total of 3 plies of the paper wiper 1 is 31.4 N / 25 mm or greater and 54.9 N / 25 mm or less, and the lateral strength in the dry state of the total of 3 plies of the paper wiper 1 is 7.8 N / 25 mm or greater and 19.6 N / 25 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a paper wiper. [Background technology]

[0002] Paper wipers made from raw materials such as pulp and recycled paper are used as industrial wipers in, for example, medical facilities, corporate and university laboratories, various manufacturing plants, food manufacturing plants, food processing plants, etc. Such paper wipers typically have a ply count of 2 to 6, and are available in a variety of product forms.

[0003] For example, Patent Document 1 discloses industrial paper wipes that are made by adding 0.125 to 1.25 parts by mass of a wet strength agent and 0.01 to 0.5 parts by mass of a softener to 100 parts by mass of constituent fibers, and then calendering the paper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-209482 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the paper wipers described above are required to have water absorbency, a pleasant feel when used, such as a comfortable touch and wiping sensation, durability, and low dust generation (for example, low paper dust falling off the wiper), the reality is that conventional paper wipers do not satisfy all of these requirements. Therefore, there is a need for the development of a paper wiper that can meet all of these requirements at a high level.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper wiper that is highly absorbent, comfortable to use, durable, and generates little dust. [Means for solving the problem]

[0007] As a result of intensive research by the inventors to achieve the above-mentioned object, the inventors have found a three-ply paper wiper made of three layers of base paper, the paper wiper being embossed, and the total basis weight of the three plies of the paper wiper being 56.0 g / m 2 More than 80.0g / m 2 The inventors have found that the total paper thickness of the three plies of the paper wiper is 0.40 mm or more and 0.62 mm or less, the total vertical strength of the three plies of the paper wiper in a dry state is 31.4 N / 25 mm or more and 54.9 N / 25 mm or less, and the total horizontal strength of the three plies of the paper wiper in a dry state is 7.8 N / 25 mm or more and 19.6 N / 25 mm or less, and have completed the present invention based on this finding.

[0008] That is, the present invention is as follows.

[0009] (1) The wiper is a three-ply paper wiper made of three sheets of base paper stacked together, and an embossment is formed on the wiper. The total basis weight of the three plies of the wiper is 56.0 g / m. 2 More than 80.0g / m 2 The total paper thickness of the three plies of the paper wiper is 0.40 mm or more and 0.62 mm or less, the total longitudinal strength of the three plies of the paper wiper in a dry state is 31.4 N / 25 mm or more and 54.9 N / 25 mm or less, and the total transverse strength of the three plies of the paper wiper in a dry state is 7.8 N / 25 mm or more and 19.6 N / 25 mm or less. (2) The paper wiper according to (1), wherein the embossment is a pin embossment. (3) The paper wiper according to (1) or (2), wherein the embossing depth of the embossing is 300 μm or more and 850 μm or less. (4) The paper wiper according to any one of (1) to (3), wherein the embossed area ratio of the embossing is 0.42% or more and 1.40% or less. (5) The paper wiper according to any one of (1) to (4), wherein the pitch between adjacent embossments is 1.0 mm or more and 3.8 mm or less. (6) The basis weight of each sheet of base paper before plying is 18.7 g / m 2 More than 26.7g / m 2 The paper wiper is described in any one of (1) to (5) below. (7) The paper wiper according to any one of (1) to (6), wherein the thickness of each base paper sheet before plying is 0.78 mm / 10 plies or more and 1.25 mm / 10 plies or less. (8) The paper wiper is the paper wiper according to any one of (1) to (7), in which three sheets of the base paper are stacked and folded in four. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a paper wiper that is highly absorbent, has a good feel when used, is durable, and generates little dust. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of a paper wiper according to this embodiment. [Figure 2] FIG. 2 is a schematic top view of the paper wiper according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0013] In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0014] Furthermore, in this specification, terms with "abbreviation" attached indicate the meaning of the term excluding "abbreviation" within the scope of common technical knowledge of a person skilled in the art, and also include the meaning itself excluding "abbreviation."

[0015] (paper wiper)

[0016] FIG. 1 is a schematic cross-sectional view of the paper wiper according to the present embodiment, and FIG. 2 is a schematic top view of the paper wiper according to the present embodiment.

[0017] The paper wiper 1 according to this embodiment is a three-ply paper wiper 1 made by stacking three base papers 11, 12, and 13. The paper wiper 1 has an embossment 20 formed thereon, and the total basis weight of the three plies of the paper wiper 1 is 56.0 g / m 2 More than 80.0g / m 2 The paper wiper 1 has a total paper thickness of 0.40 mm or more and 0.62 mm or less, a total longitudinal strength of 31.4 N / 25 mm or more and 54.9 N / 25 mm or less in a dry state of the three plies of the paper wiper 1, and a total transverse strength of 7.8 N / 25 mm or more and 19.6 N / 25 mm or less in a dry state of the three plies of the paper wiper 1.

[0018] According to this embodiment, by forming three plies of base papers 11, 12, and 13 and embossing them to produce a paper wiper 1 with specific basis weight, thickness, longitudinal strength, and lateral strength, it is possible to meet all requirements at a high level, such as water absorption, usability such as feel and wiping comfort, durability, and low dust generation. Note that dust generation here refers to paper dust (shedded paper dust) that falls off the paper wiper 1 during use or production, and includes, for example, fiber pieces and filler powder from the paper wiper 1.

[0019] When the base papers 11, 12, and 13 are made using a papermaking machine capable of forming a dryer surface and a felt surface, it is preferable that the top and bottom surfaces of the three plies of base papers 11, 12, and 13 be arranged such that the dryer surface is the paper surface. In the case of Figure 1, it is preferable that the surface side of the top base paper 11 be the dryer surface, and the back surface of the bottom base paper 13 be the dryer surface. This arrangement improves the feel of both the surface (e.g., the surface of the base paper 11) and the back surface (e.g., the back surface of the base paper 13) of the paper wiper 1, and also makes wiping more comfortable. Note that the arrangement of the paper surface of the intermediate base paper 12 sandwiched between the top base paper 11 and the bottom base paper 13 need not be particularly limited.

[0020] The basis weight of the three plies of paper wiper 1 (the total of the three ply-up base papers 11, 12, and 13) is 56.0 g / m 2 More than 80.0g / m 2 The basis weight is 60.0 g / m 2 More than 76.0g / m 2 It is preferable that the basis weight is equal to or less than 10 ...

[0021] The total thickness of the three plies of the paper wiper 1 is 0.40 mm or more and 0.62 mm or less. This thickness is preferably 0.45 mm or more and 0.57 mm or less. This thickness is the product paper thickness of the paper wiper 1. By keeping the product basis weight and product paper thickness of the paper wiper 1 within the above ranges, the paper wiper will have good usability, such as water absorbency, feel, and wiping comfort, and will generate little dust.

[0022] The total longitudinal strength of the three plies of the paper wiper 1 in a dry state is 31.4 N / 25 mm or more and 54.9 N / 25 mm or less, and preferably 35.2 N / 25 mm or more and 51.0 N / 25 mm or less.

[0023] The longitudinal strength here refers to the tensile strength in the longitudinal width direction of the three plies of the paper wiper 1 when dry. The longitudinal strength can be measured in accordance with JIS P 8113. The longitudinal width direction refers to the machine direction (MD) of the paper wiper 1 during production.

[0024] The total lateral strength of the three plies of the paper wiper 1 in a dry state is 7.8 N / 25 mm or more and 19.6 N / 25 mm or less. This lateral strength is preferably 9.8 N / 25 mm or more and 15.7 N / 25 mm or less. By keeping the longitudinal strength and lateral strength of the paper wiper 1 within the above ranges, the paper wiper has a good feel in use, such as a good touch and wiping comfort, and is also durable.

[0025] The term "transverse strength" used herein refers to the tensile strength in the width direction of the three plies of the paper wiper 1 when dry. The width strength can be measured in accordance with JIS P 8113. The width direction refers to the direction perpendicular to the flow direction of the paper wiper 1 during production (CD; Cross Direction).

[0026] The paper wiper 1 has an embossment 20 formed on a base material 10 made of three stacked base papers 11, 12, and 13. As shown in Fig. 1, the embossment 20 is formed on the three base papers 11, 12, and 13. By forming the embossment on the paper wiper 1, the paper thickness and strength of the paper wiper 1 can be adjusted to an appropriate range, resulting in a paper wiper that has good usability in terms of absorbency, feel, and wiping comfort, and that is durable and generates little dust.

[0027] The shape of the embossing is not particularly limited, and examples thereof include pin embossing, dot embossing, and decorative embossing. Pin embossing refers to a concave shape formed by embossing three base papers 11, 12, and 13, respectively, to integrate them, and the shape is pin-shaped (approximately conical, pierced with a sharp needle). Dot embossing refers to a concave shape formed by embossing three base papers 11, 12, and 13, respectively, to integrate them, and the shape is not particularly limited, but includes embossing in the shape of a rectangular parallelepiped, cylindrical, triangular prism, etc. (a type pressed with a flat surface). Decorative embossing refers to an embossing in which the pressed shape is some kind of pattern (such as a flower, a company logo, or a character). Among these, pin embossing is preferred because it results in a thicker paper and a higher water absorption capacity when the three base papers are embossed and integrated.

[0028] The embossing depth D is preferably 300 μm or more and 850 μm or less, and more preferably 420 μm or more and 700 μm or less. By setting the embossing depth D within this range, it is possible to produce a paper wiper that is durable and has good usability, such as water absorbency, feel, and wiping comfort. The embossing depth D here refers to the depth from the bottom of the outer surface of the embossment 23 of the base paper 13, which is the bottom layer (lowest), to the outer surface of the base paper 11, which is the top layer (top) when three base papers 11, 12, and 13 are stacked together (see Figure 1). The embossing depth D can be measured in accordance with the method described in the Examples below.

[0029] In this embodiment, the surface of the paper wiper 1 may have portions with a shallow embossing depth D and portions with a deep embossing depth D. Alternatively, the embossing may be formed by sloping the surface so that the embossing depth D gradually becomes shallower (or deeper). In the case of a paper wiper 1 having different embossing depths D, it is sufficient that the paper wiper 1 has at least embossings that satisfy the above-mentioned conditions. Furthermore, according to this embodiment, it is preferable that 50% or more of the embossings on the paper wiper 1 satisfy the above-mentioned conditions, more preferably 70% or more of the embossings satisfy the above-mentioned conditions, even more preferably 90% or more of the embossings satisfy the above-mentioned conditions, and even more preferably 100% of the embossings (all embossings) satisfy the above-mentioned conditions.

[0030] The embossment area ratio of the embossments 20 is preferably 0.42% or more and 1.40% or less, and more preferably 0.57% or more and 1.05% or less. By setting the embossment area ratio within this range, it is possible to produce a paper wiper that is durable and has good usability, such as water absorbency, feel, and wiping comfort. The embossment area ratio refers to the percentage of the total area of ​​the embossments 20 per unit area when viewed from above the paper wiper 1 (see FIG. 2) (total number of embossed areas per unit area; %). Specifically, it is the area ratio of 30 embossments measured in accordance with the method described in the Examples below.

[0031] In this embodiment, the surface of the paper wiper 1 may have areas with a low embossed area ratio (sparsely arranged embossments) and areas with a high embossed area ratio (densely arranged embossments). Alternatively, the embossing may be formed with a gradient so that the embossed area ratio gradually decreases (or increases). In the case of a paper wiper 1 having areas with different embossed area ratios, it is sufficient that the embossed area ratios of 30 adjacent embossments in the embossed area of ​​the paper wiper 1 (the entire embossed area) satisfy the above-mentioned condition. Furthermore, according to this embodiment, it is preferable that 50% or more of the embossed area of ​​the paper wiper 1 satisfy the above-mentioned condition, more preferably 70% or more of the area satisfies the above-mentioned condition, even more preferably 90% or more of the area satisfies the above-mentioned condition, and even more preferably 100% of the area (the entire embossed area) satisfies the above-mentioned condition.

[0032] The pitch distance P between adjacent embossments 201, 202 of the embossments 20 is preferably 1.0 mm or more and 3.8 mm or less, and more preferably 1.5 mm or more and 3.2 mm or less. By setting the pitch distance P within this range, the paper wiper can be made durable and have good usability, such as water absorbency, feel, and wiping comfort. The pitch distance P here refers to the linear distance between the centers of gravity O1, O2 of adjacent embossments 201, 202, and is the minimum value of the pitch distance P between the embossments 20 arranged on the substrate 10. The pitch distance P can be measured in accordance with the method described in the Examples below.

[0033] In this embodiment, the surface of the paper wiper 1 may have areas with a small pitch interval P (where the embossments are densely arranged) and areas with a large pitch interval P (where the embossments are densely arranged). Alternatively, the embossing may be formed with an inclination so that the pitch interval P gradually decreases (or increases). In the case of a paper wiper 1 having areas with different pitch intervals P, it is sufficient that the smallest pitch interval P (minimum value of pitch interval P) in the embossed area of ​​the paper wiper 1 (the entire embossed area) satisfies the above-mentioned condition. Furthermore, according to this embodiment, it is preferable that 50% or more of the embossed area of ​​the paper wiper 1 satisfies the above-mentioned condition for the pitch interval P, more preferably 70% or more of the area satisfies the above-mentioned condition for the pitch interval P, even more preferably 90% or more of the area satisfies the above-mentioned condition for the pitch interval P, and even more preferably 100% of the area (the entire embossed area) satisfies the above-mentioned condition for the pitch interval P.

[0034] (base paper)

[0035] Next, the base papers 11, 12, and 13 before ply-up will be described.

[0036] The basis weight per sheet of base papers 11, 12, and 13 before plying is 18.7 g / m 2 More than 26.7g / m 2 Preferably, it is 20.0 g / m or less. 2 More than 25.3g / m 2 By setting the basis weight within this range, when the paper wiper 1 is made by stacking three sheets of base paper, it is possible to obtain a paper wiper that has good water absorbency, good feel in use, such as touch and wiping comfort, and generates little dust.

[0037] The thickness of each of the base papers 11, 12, and 13 before plying is preferably 0.78 mm / 10 plies or more and 1.25 mm / 10 plies or less, and more preferably 0.89 mm / 10 plies or more and 1.13 mm / 10 plies or less. By setting the paper thickness within this range, when three base papers are stacked to produce a paper wiper 1, the wiper has good water absorbency, a good feel when used, such as a good touch and wiping sensation, and generates little dust. Note that the paper thickness here refers to the thickness when ten sheets of base paper 11, 12, and 13 are stacked together, and corresponds to the thickness (10 plies) of ten sheets of base paper 11, 12, and 13 stacked together.

[0038] Materials that can be used for the base papers 11, 12, and 13 that make up the paper wiper 1 include, for example, wood pulp (such as bleached softwood kraft pulp (NBKP) and bleached hardwood kraft pulp (LBKP)), non-wood pulp (such as hemp pulp and bamboo pulp), and chemical fibers (such as cellulose-based fibers, olefin-based chemical fibers, and polyester-based fibers). Of these, it is preferable to use wood pulp, which has particularly excellent water absorption properties.

[0039] The wood species of hardwood bleached kraft pulp (LBKP) is preferably pulp made from hardwoods such as eucalyptus, poplar, acacia, and oak, while the wood species of softwood bleached kraft pulp (NBKP) is preferably pulp made from softwoods such as fir, pine, cedar, and cypress.

[0040] The base papers 11, 12, and 13 preferably have a wood pulp content of 70% by mass or more, and more preferably 90% by mass or more.

[0041] When the base papers 11, 12, and 13 contain NBKP, the content thereof is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0042] When the base papers 11, 12, and 13 contain LBKP, the content is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0043] Furthermore, the base papers 11, 12, and 13 may contain recycled paper pulp derived from milk cartons, but the recycled paper pulp content is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably none. By controlling the recycled paper pulp content within this range, the balance of water absorbency, strength, low dust generation, etc. of the paper wiper 1 is further improved.

[0044] In this embodiment, recycled paper pulp refers to recycled paper pulp derived from milk cartons. The recycled paper pulp derived from milk cartons is primarily made of softwood pulp, which makes it easy to ensure the strength of the paper wiper 1. However, the quality varies widely, and if the content is too high, it tends to affect the quality of the product. Therefore, it is preferable to keep the content within the above range. Therefore, for example, the above-mentioned NBKP and LBKP do not fall under the category of recycled paper pulp.

[0045] The color tone of the paper wiper 1 is not particularly limited, and may be white, obtained by using bleached pulp or the like for the base papers 11, 12, and 13, or brown, obtained by using unbleached pulp or the like for the base papers 11, 12, and 13.

[0046] The paper wiper 1 may also contain other additives as long as the effects of this embodiment are not impaired. Examples of such additives include softeners, wet strength agents, and dry strength agents. However, the total content of the additives is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less.

[0047] The base papers 11, 12, and 13 can be produced by a papermaking process using a papermaking machine. In the papermaking process, it is preferable to use a papermaking machine that can form a dryer surface and a felt surface. For example, it is preferable to perform a pressing process in which water is removed using a press roll and a felt, and a drying process in which drying is performed using a Yankee dryer, and it is preferable to use a papermaking machine equipped with such devices. This allows the base papers 11, 12, and 13 to be formed with a dryer surface and a felt surface, which improves the feel and makes them more comfortable to wipe.

[0048] In the papermaking process, for example, the basis weight of the base papers 11, 12, and 13 can be increased by, for example, increasing the amount of pulp used. The thickness of the base papers 11, 12, and 13 can be increased by, for example, increasing the amount of pulp used. The longitudinal strength and transverse strength can be increased by, for example, increasing the amount of pulp used, strengthening beating by DDR or the like, adding wet strength agents or dry strength agents, etc.

[0049] (Product form, etc.)

[0050] The above-mentioned paper wiper 1 may be formed by plying together base papers 11, 12, and 13 to form embossments 20, but may also be formed by folding the plyed-up base papers 11, 12, and 13 into multiple sheets (for example, folded into thirds or fourths) as necessary. One example of a suitable embodiment is a paper wiper 1 formed by stacking three sheets of base paper 11, 12, and 13 and folding them into fourths.

[0051] For example, folding into four can be achieved by folding the approximately rectangular paper wiper 1 in half and then folding it again vertically in half, such as a cross fold, a right-angle fold, or a crisscross fold. Other folding methods include an outward fold (such as a W fold), a rolled fold, a semi-rolled fold, or a gate fold. In this way, a suitable folding method can be selected depending on the intended use of the product.

[0052] The dimensions and shape of the paper wiper 1 as a product are not particularly limited, and it can be a shape suitable for the product, taking into consideration the manner of use, purpose of use, etc. For example, it may be rectangular (rectangular, square), circular, oval, polygonal, etc., but when used in a pop-up storage box for paper wipers, a rectangular shape is preferable.

[0053] For example, when the paper wiper 1 according to this embodiment is rectangular, the vertical width of the paper wiper 1 is preferably 320 mm to 350 mm, and more preferably 325 mm to 345 mm. The horizontal width of the paper wiper 1 is preferably 370 mm to 395 mm, and more preferably 375 mm to 390 mm. Furthermore, it is preferable that both the vertical width and the horizontal width are within the above-mentioned ranges.

[0054] As described above, the paper wiper 1 according to this embodiment is highly absorbent, comfortable to use, durable, and generates little dust. Therefore, the paper wiper 1 according to this embodiment can be suitably used in research laboratories and other laboratories, manufacturing plants for electronic components, cosmetics, pharmaceuticals, food, and various other materials and products, and medical facilities such as hospitals and nursing homes. [Example]

[0055] The present invention will be explained in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples in any way.

[0056] Example 1

[0057] (Preparation of Paper Wiper 1)

[0058] First, softwood bleached kraft pulp (NBKP) was used as the material, and a pressing process was performed in which it was dewatered using a press roll and a felt, and a drying process was performed in which it was dried using a Yankee dryer, to produce base papers 11, 12, and 13 using a papermaking machine that can form a dryer surface and a felt surface on the base paper. These base papers 11, 12, and 13 were then stacked in three plies to form a laminate. When stacking the three plies of base papers 11, 12, and 13, the paper surfaces were arranged so that both the top surface (the surface of the top base paper 11 in Figure 1) and the bottom surface (the back surface of the bottom base paper 13 in Figure 1) of the laminate were the dryer surfaces. Specifically, in Fig. 1, the uppermost base paper 11 (i.e., the outermost surface of the laminate) was the dryer surface and the lower surface was the felt surface, the middle base paper 12 was the felt surface and the lower surface was the dryer surface, and the lowermost base paper 13 was the felt surface and the lower surface (i.e., the back surface of the laminate) was the dryer surface. Next, this laminate was embossed by pin embossing or dot embossing and folded into four to produce paper wiper 1 having the structure shown in Figs. 1 and 2.

[0059] (Measurement of physical properties)

[0060] The product basis weight is the basis weight of the three plies of the paper wiper 1 (the total of the three ply-up base papers 11, 12, and 13), and was measured in accordance with JIS P 8124.

[0061] The product paper thickness is the total thickness of the three plies of paper wiper 1 (the total of the three ply-up base papers 11, 12, and 13), and was measured under the conditions of JIS P 8111 (23±1°C, 50±2% relative humidity) using a thickness gauge (Ozaki Seisakusho's upright dial thickness gauge "PEACOCK R1-B type"), applying a pressure of 3.7 kPa to the measuring probe.

[0062] The longitudinal strength of the three plies of paper wiper 1 in a dry state (longitudinal strength of product strength) is the tensile strength of paper wiper 1 (three plies of base paper 11, 12, and 13) in the longitudinal width direction when dry, and was measured in accordance with JIS P 8113. The longitudinal width direction here refers to the machine direction (MD) in which paper wiper 1 is manufactured, and refers to the strength in the short direction (longitudinal width direction) of paper wiper 1.

[0063] The total lateral strength of the three plies of paper wiper 1 in a dry state (lateral strength of product strength) is the tensile strength in the width direction of paper wiper 1 (the three plies of base paper 11, 12, and 13) when dry, and was measured in accordance with JIS P 8113. The width direction here refers to the direction perpendicular to the flow direction during the manufacture of paper wiper 1 (CD; Cross Direction), and refers to the strength in the longitudinal direction (width direction) of paper wiper 1.

[0064] Regarding the embossing shape, the "pin embossing" is a cone shape, and the "dot embossing" is a cylinder shape.

[0065] The pitch interval of the embossed shapes was measured by imaging the surface of the paper wiper 1, which was the object of measurement, from above (see Figure 2), using a microscope (Keyence Corporation, Digital Microscope "VHX-6000") at a magnification of 20x, and measuring the linear distance between the centers of gravity O1 and O2 of adjacent embossments 201 and 202 in the image obtained. In this way, the pitch interval was measured at 30 points, and the arithmetic average of these measurements was taken as the pitch interval.

[0066] The embossed area ratio of the embossed shape was measured by photographing the surface of the paper wiper 1, which was the object of measurement, viewed from above (see Figure 2), using a microscope (Keyence Corporation, digital microscope "VHX-6000") at a magnification of 20x, and in the photographed image, the area of ​​the embossments 21 formed on the outermost base paper 11 of the three base papers 11, 12, and 13, when viewed from above, was calculated. The total value of 30 points calculated in this way was converted into a ratio per unit area (area ratio %). Specifically, 30 adjacent embosses 21 were selected from the captured image, and the smallest circumscribing rectangle (rectangle or square) encompassing all 30 embosses was defined as the unit area. The emboss area ratio was then calculated using the following formula: Embossed area ratio (%) = Total area of ​​30 adjacent embossed points / Area of ​​the smallest circumscribed rectangle that includes all 30 embossed points x 100

[0067] The embossing depth of the embossed shape was measured by taking a cross-sectional image of the surface of the paper wiper 1 to be measured (see FIG. 1) using a one-shot 3D shape measuring machine (Keyence Corporation, digital microscope "VR-3000") at a magnification of 12x, and in the obtained image, with three sheets of base paper 11, 12, and 13 stacked together, the depth D was measured from the bottom of the outer surface of the embossment 23 of base paper 13, the bottommost layer (lowest), to the outer surface of base paper 11, the topmost layer (top). In this way, the embossing depth D was measured at 30 points, and the arithmetic average of these measurements was taken as the embossing depth.

[0068] The basis weight of one sheet of base papers 11, 12 and 13 was measured in accordance with JIS P 8124.

[0069] The thickness of each base paper sheet was measured for base papers 11, 12, and 13 under the conditions of JIS P 8111 (23±1°C, 50±2% relative humidity) using a thickness gauge (Ozaki Seisakusho's upright dial thickness gauge "PEACOCK R1-B type"), applying a pressure of 3.7 kPa to the measuring probe.

[0070] Unless otherwise specified, the measurements and evaluations in the examples were carried out after maintaining the sample in an equilibrium state under the temperature and humidity conditions specified in JIS P 8111 (23±1° C., 50±2% RH).

[0071] <Examples 2 to 8 and Comparative Examples 1 to 5>

[0072] Paper wipers were produced in the same manner as in Example 1, except that the conditions were changed to those shown in Tables 1 and 2.

[0073] <Evaluation>

[0074] (Total Water Absorbency (TWA) To measure the water absorbency (TWA), the obtained paper wiper 1 was first cut into a 76 x 76 mm square test piece, and the dry mass (W1) was measured. After immersing the test piece in distilled water for 2 minutes, the test piece was hung in a stretched state (RH 100%) with one corner of the test piece positioned at the top, and this top and the two adjacent corners were supported. After leaving the test piece for 30 minutes, the mass (W2) was measured. The value of (W2 - W1) was then calculated, and this value was used to measure the mass of the sample per 1 m. 2 Water retention capacity per unit (g / m 2 ) and used as the water absorption rate.

[0075] The following items were evaluated as part of a sensory evaluation by 60 people. For each item, 60 people rated the items on a scale of 1 to 5 based on the following criteria, and the average score was calculated. The average score was then used to evaluate the products based on the following criteria.

[0076] (Evaluation of wiping comfort) A sample prepared under the above conditions was used to wipe an object (a plastic desk on which 50 mL of water had been spilled) at 23±1°C and 50±2% RH, and the wiping feel was evaluated on a 5-point scale from 1 to 5. 4 and 5 points: The wiping experience was particularly good, and the object could be wiped smoothly. 3 points: The wiping was smooth and the object could be wiped smoothly. 1 point, 2 points: The object was difficult to wipe. comprehensive evaluation "◎": The average score of 60 people is 4.0 or higher "Good": The average score of 60 people is between 3.0 and 4.0 points "×": The average score of 60 people is less than 3.0 points

[0077] (Durability rating) Samples prepared under the above conditions were used to wipe an object (a plastic desk on which 50 mL of water had been spilled) at 23±1°C and 50±2% RH, and the durability of the samples was evaluated on a 5-point scale from 1 to 5. 4 and 5 points: It felt particularly hard to tear when wiping the object. 3 points: It felt less likely to tear when wiping the object. 1 point, 2 points: When wiping the object, it tore or felt like it was easily torn. comprehensive evaluation "◎": The average score of 60 people is 4.0 or higher "Good": The average score of 60 people is between 3.0 and 4.0 points "×": The average score of 60 people is less than 3.0 points

[0078] (Evaluation of low dust generation) A sample prepared under the above conditions was used to wipe an object (a plastic desk on which 50 mL of water had been spilled) at 23±1°C and 50±2% RH, and the presence or absence of dust was evaluated on a 5-point scale from 1 to 5. 4 and 5 points: There was very little fuzz when wiping the object. 3 points: There was little fuzz when wiping the object. 1 point, 2 points: When wiping the object, there was a lot of fluffing, and dust such as paper dust was observed on the object. comprehensive evaluation "◎": The average score of 60 people is 4.0 or higher "Good": The average score of 60 people is between 3.0 and 4.0 points "×": The average score of 60 people is less than 3.0 points

[0079] The conditions and evaluation results for each example and comparative example are shown in Tables 1 and 2. In the tables, "pin" means pin embossing, and "dot-like" means dot-like embossing (cylindrical shape).

[0080] [Table 1]

[0081] [Table 2]

[0082] From the above, it was at least confirmed that the paper wiper 1 of this example has high water absorption, a good feel when used, is durable, and generates little dust. [Explanation of symbols]

[0083] 1: Paper wiper, 10: Base material, 11,12,13: Original paper, 20,21,22,23,201,202: embossed, D: embossing depth, P: pitch interval, O1,O2: Center of gravity

Claims

1. It is a three-ply paper wiper made of three layers of base paper. The paper wiper has an embossment formed thereon, The total basis weight of the three plies of the paper wiper is 60.0 g / m ２ 76.0g / m or more ２ is as follows: The total thickness of the three plies of the paper wiper is 0.40 mm or more and 0.62 mm or less, The total longitudinal strength of the three plies of the paper wiper in a dry state is 31.4 N / 25 mm or more and 54.9 N / 25 mm or less, The total lateral strength of the three plies of the paper wiper in a dry state is 7.8 N / 25 mm or more and 19.6 N / 25 mm or less, The embossment is a pin embossment having a conical shape, The embossing depth of the embossing is 300 μm or more and 850 μm or less, The thickness of each base paper sheet before plying is 0.78 mm / 10 plies or more and 1.25 mm / 10 plies or less, The embossing area ratio of the embossing is 0.42% or more and 1.40% or less, the basis weight per sheet of the base paper before plying is 20.0 g / m 2 or more and 25.3 g / m 2 or less; Paper wiper.

2. The pitch between adjacent embossments is 1.0 mm or more and 3.8 mm or less. The paper wiper of claim 1 .

3. The paper wiper is made by stacking three sheets of the base paper and folding them into four. The paper wiper according to claim 1 or 2.

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