Paper towel and paper towel roll

Abstract

[Problem] To enhance the absorbency of a paper towel. [Solution] A paper towel wherein: the paper thickness is 1.5-4.5 mm / 5 units; the dry tensile strength in the longitudinal direction is 1000-3000 cN / 25 mm; the dry tensile strength in the lateral direction is 300-800 cN / 25 mm; the wet tensile strength in the lateral direction is 80-250 cN / 25 mm; the value expressed by (water absorption per unit basis weight) / (MMD) is 0.2-0.8; and the value expressed by (oil absorption per unit basis weight) / (MMD) is 0.2-0.8.

Description

Kitchen paper and kitchen paper rolls

[0001] This invention relates to kitchen paper and kitchen paper rolls in which strip-shaped kitchen paper is wound into a roll.

[0002] Kitchen paper is known to come in several forms: multiple sheets of square or rectangular paper stacked together and bundled, and rolls of strip-shaped kitchen paper wound into a roll. Some kitchen paper rolls have perforations at predetermined intervals along the length, and the number of sheets that can be torn off at the perforations is called the "cut count," which, along with the roll length, indicates the period or number of times the roll can be used.

[0003] In recent years, due to the need to reduce environmental impact, convenience, and changes in consumers' lifestyles, there has been a growing demand for everyday items such as kitchen paper rolls that are easy to store, easy to stock, and can be used for extended periods. For example, in the case of kitchen paper rolls, there has been an increase in products with longer rolls, such as those with more cuts or roll length. Also, in the case of bundled products, there are now products that have a larger number of sheets of kitchen paper in each bundle.

[0004] On the other hand, kitchen paper is mainly used in the kitchen for various purposes such as cooking, cleaning, wiping, and filtering oil. Its uses are diverse, but it is frequently used for draining water from food, wiping off moisture from dishes, and wiping up kitchen messes. For this reason, kitchen paper needs to be absorbent of water and oil, and resistant to tearing.

[0005] The absorbency of kitchen paper can be improved by increasing its basis weight, but simply increasing the basis weight not only increases costs but can also decrease its strength. In particular, simply increasing the basis weight increases the diameter of rolls and the size of bundles, which increases transportation costs.

[0006] In order to keep transportation costs similar to conventional methods, if the roll diameter and bundle size are kept to common sizes and diameters, it becomes necessary to roll them tightly and rigidly or compress them during packaging. This results in a decrease in paper thickness and bulk, making it difficult to improve absorbency.

[0007] Patent No. 5373208

[0008] Therefore, the main objective of the present invention is to provide a kitchen paper that can improve absorbency without increasing the basis weight and is suitable for long rolls and products with a large number of sheets.

[0009] The first solution to the above problem is a kitchen paper characterized by having a paper thickness of 1.5 to 4.5 mm / 5 sets, a dry tensile strength in the longitudinal direction of 1000 to 3000 cN / 25 mm, a dry tensile strength in the transverse direction of 300 to 800 cN / 25 mm, a wet tensile strength in the transverse direction of 80 to 250 cN / 25 mm, a value of (water absorption per unit basis weight) / (MMD) of 0.2 to 0.8, and a value of (oil absorption per unit basis weight) / (MMD) of 0.2 to 0.8.

[0010] The second method is a kitchen paper relating to the first method described above, wherein the vertical MMD is 5 to 30, the horizontal MMD is 7 to 60, and the aspect ratio of the MMD ((vertical MMD) / (horizontal MMD)) is 0.1 to 1.0.

[0011] The third method is a kitchen paper according to the first or second method, wherein the kitchen paper is two-ply and has a laminated structure in which sheets with embossed irregularities are laminated with their convex surfaces facing each other.

[0012] The fourth means is a kitchen paper roll in which the strip-shaped kitchen paper according to the first to third described above is wound into a roll shape, characterized in that the roll length is 10 to 30 m, the roll diameter is 90 to 130 mm, and the roll hardness is 0.4 kgf or more and 1.6 kgf or less.

[0013] According to the present invention, it is possible to improve absorbency without increasing the basis weight and provide kitchen paper suitable for long rolls and products with a large number of sheets.

[0014] This is a cross-sectional view of kitchen paper illustrating the form of double embossing according to this embodiment. This is a cross-sectional view of kitchen paper illustrating another form of double embossing according to this embodiment. This is a perspective view of a roll of kitchen paper according to this embodiment.

[0015] Next, embodiments of the kitchen paper and kitchen paper roll according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the illustrated shapes or embodiments. Modifications are possible as long as they do not impede the effects of the present invention.

[0016] The kitchen paper according to this embodiment is mainly composed of pulp and has a laminated structure in which one sheet is a single ply or two or more sheets are stacked together. The number of plies is not limited, but two plies are preferred.

[0017] Furthermore, the basis weight of the kitchen paper according to this embodiment is not necessarily limited, but is preferably 34 to 70 g / m² per set. ２ More preferably 38 to 66 g / m² ２ And, particularly preferably, 40 to 50 g / m ２ This is the case. Note that a set is defined as one ply for single-ply paper and multiple plies for multi-ply paper. The basis weight is measured according to the basis weight measurement method of JIS P 8124 (1998). The kitchen paper according to this embodiment can improve absorbency at least within this basis weight range. Furthermore, it can be made into a long-length product or a product with a large number of sheets. In particular, for the kitchen paper with the preferred number of plies mentioned above, which is two plies, the basis weight per sheet is preferably 17 to 34 g / m², although this is not necessarily limited to this. ２ More preferably, 19 to 33 g / m² ２ The most preferred amount is 20 to 25 g / m². ２ That is the case.

[0018] The kitchen paper according to this embodiment has a paper thickness of 1.5 to 4.5 mm per 5 sets. Preferably, it is 2.2 to 4.5 mm per 5 sets. This preferred range is particularly desirable in the case of 2-ply paper. Here, a set is defined as one ply for 1-ply paper or multiple plies for multi-ply paper. For example, in a 2-ply laminated structure, 5 sets consist of 10 sheets, and in a 3-ply laminated structure, 5 sets consist of 15 sheets. If the paper thickness is 1.5 to 4.5 mm per 5 sets, sufficient thickness and bulkiness can be felt, and sufficient absorbency can be obtained even with long rolls or a large number of sheets. The paper thickness is measured as follows: After thoroughly humidifying the test piece under the conditions of JIS P 8111 (1998) (usually for about 8 hours), the thickness is measured in the stacked state of 5 sets using a dial thickness gauge (thickness measuring instrument) "PEACOCK G type" (manufactured by Ozaki Seisakusho) under the same conditions. Specifically, after confirming that there is no dust or debris between the plunger and the measuring platform, lower the plunger onto the measuring platform, move the dial thickness gauge's scale to set the zero point, then raise the plunger and place the sample (5 stacked sets) on the test platform, slowly lower the plunger and read the gauge reading at that time. During measurement, the plunger should only be rested on the platform and not pressed down. The plunger's terminals are made of metal, and the circular surface with a diameter of 30 mm should be perpendicular to the paper surface. The paper thickness should be the average value obtained from 10 measurements.

[0019] Furthermore, the kitchen paper according to this embodiment has a dry tensile strength in the longitudinal direction of 1,000 to 3,000 cN / 25 mm, a dry tensile strength in the transverse direction of 300 to 800 cN / 25 mm, and a wet tensile strength in the transverse direction of 80 to 250 cN / 25 mm. A dry tensile strength in the longitudinal direction of 1,300 to 2,500 cN / 25 mm is preferred. This preferred range is particularly desirable when the constituent pulp is bleached pulp such as NBKP or LBKP. The longitudinal direction of the paper is also called the MD direction and is the flow direction during papermaking. The transverse direction of the paper is also called the CD direction and is the direction perpendicular to the flow direction (MD direction) during papermaking. When the dry tensile strength and wet tensile strength are within the above ranges, the kitchen paper can be sufficiently tear-resistant while also providing sufficient absorbency even in long rolls or with a large number of sheets. The dry tensile strength and wet tensile strength can be adjusted by the ratio of dry strength agent, wet strength agent, type of pulp fiber, and type of pulp fiber.

[0020] Dry tensile strength is measured according to JIS P 8113 (2006). Specifically, the test specimens used are cut from a single product set in both the longitudinal and transverse directions to approximately 25 mm wide (±0.5 mm) x 150 mm long. The testing machine used is a Minebea Co., Ltd. load cell tensile testing machine TG-200N or an equivalent machine. The gripping distance is set to 100 mm and the tensile speed to 100 mm / min. Five sets of samples are prepared in both longitudinal and transverse directions, and measurements are taken five times. The average of these measurements is taken as the dry tensile strength in each direction.

[0021] The wet tensile strength is measured according to JIS P 8135 (1998). Specifically, the test specimen is made from a single product set cut to approximately 25 mm wide (±0.5 mm) x 150 mm long. The testing machine used is a Minebea Co., Ltd. load cell tensile testing machine TG-200N or an equivalent machine. The grip spacing is set to 100 mm and the tensile speed to 100 mm / min. The test specimen is cured in a 105°C dryer for 10 minutes. After clamping both ends of the test specimen to the grips of the testing machine, water is applied horizontally to the center of the specimen in a width of approximately 10 mm using a water-soaked flat brush. Then, a tensile load is immediately applied to the paper piece in the vertical direction, and the measurement is performed by reading the indicated value (digital value) when the paper breaks. Five sets of samples are prepared and measured five times, and the average of the measured values ​​is taken as the wet tensile strength.

[0022] On the other hand, the kitchen paper according to this embodiment has a value of (water absorption per unit basis weight) / (MMD) of 0.2 to 0.8, and a value of (oil absorption per unit basis weight) / (MMD) of 0.2 to 0.8. MMD is the average deviation of the coefficient of friction and is a numerical value that represents the microscopic surface characteristics of the paper. The kitchen paper according to this embodiment determines the amount of absorption based on surface characteristics rather than basis weight. When the values ​​of (water absorption per unit basis weight) / (MMD) and (oil absorption per unit basis weight) / (MMD) are within the above range, the absorbency can be improved without increasing the basis weight, and kitchen paper suitable for long rolls or products with a large number of sheets can be made. Note that in the values ​​of (water absorption per unit basis weight) / (MMD) and (oil absorption per unit basis weight) / (MMD), MMD is 10 times the sum of the measured values ​​of MMD in the vertical direction and MMD in the horizontal direction.

[0023] On the other hand, the water absorption capacity per unit area of ​​the kitchen paper according to this embodiment is not necessarily limited, but is 350 to 800 g / m². ２ It is desirable that this be the case. Also, the amount of oil absorbed per unit area is not necessarily limited, but is generally between 400 and 800 g / m². ２ This is desirable. With these water and oil absorption capacities, it can be said that it has sufficient water absorption.

[0024] Furthermore, in this embodiment, the kitchen paper preferably has a vertical MMD of 5 to 30, a horizontal MMD of 7 to 60, and an MMD aspect ratio ((vertical MMD) / (horizontal MMD)) of 0.1 to 1.0. In particular, the MMD aspect ratio ((vertical MMD) / (horizontal MMD)) is preferably 0.1 to 0.9. Note that the vertical and horizontal MMD values ​​should be 10 times the measured MMD values ​​below. When the vertical and horizontal MMD values ​​and the MMD aspect ratio ((vertical MMD) / (horizontal MMD)) are within the above range, the paper has sufficient smoothness for use as kitchen paper, and its absorbency can be improved without increasing the basis weight, making it easy to produce kitchen paper suitable for long rolls or products with a large number of sheets. In particular, a characteristic feature of the kitchen paper according to this embodiment is that the MMD value in the lateral direction is high, and the MMD-to-aspect ratio ((vertical MMD) / (horizontal MMD)) is between 0.1 and 1.0. The sheet that makes up the kitchen paper is crepe paper with fine irregularities (crepe) on its surface. Generally, in order to increase the smoothness of this sheet, the MMD in the lateral direction is not increased, and only the MM in the vertical direction is increased. In the kitchen paper according to this embodiment, the MMD in the lateral direction is high, and the MMD-to-aspect ratio ((vertical MMD) / (horizontal MMD)) is 1 or less, resulting in a surface characteristic where the surface is roughened to a degree that does not feel rough. This surface characteristic adjusts the elongation and tensile strength of the sheet in both the vertical and horizontal directions, and also improves absorbency without increasing the basis weight by roughening the surface, making it easier to create kitchen paper suitable for long rolls or products with a large number of sheets. Here, the values ​​of the vertical and horizontal MMDs and the aspect ratio of the MMDs ((vertical MMD) / (horizontal MMD)) can be adjusted, for example, by selecting a known creping doctor blade for forming dry crepes, adjusting the blade angle and creping ratio. Alternatively, adjustments can be made by creating irregularities on the surface of the wet paper before dry crepe formation using wet creping or fabric press papermaking techniques.However, adding both wet and dry crepes increases costs, and the fabric press papermaking technology requires dedicated papermaking equipment. Therefore, it is desirable that the kitchen paper according to this embodiment does not use the fabric press papermaking technology and has only dry crepes. Surface characteristics are also related to the pulp fiber type, pulp blending ratio, and degree of beating, but these can be adjusted within known limits.

[0025] Here, (water absorption per unit basis weight) is the value measured as follows. The test environment is 23°C and 50% humidity, and the test specimen is cut to 100 mm in the vertical direction and 100 mm in the horizontal direction (±0.5 mm). Note that the test specimen is kept as a single set and not as a sheet. First, the mass of the test specimen before water absorption is measured. Distilled water at 23°C is placed in a tray larger than the test specimen (for example, inner dimensions: 215 mm x 160 mm) to a depth of about 20 mm, and the test specimen is spread out on a rigid flat mesh larger than the test specimen and placed in the tray with distilled water, so that the test specimen is in contact with the water surface without being submerged, and the test specimen is immersed. Note that the flat mesh on which the test specimen is placed has an outer frame made of wire measuring 120 mm x 120 mm, an inner frame made of wire measuring 20 mm grid arranged within this outer frame, and a handle for handling. Next, visually confirm that the water has sufficiently permeated the surface of the test specimen. Then, raise the flat mesh straight above the water surface and leave it still for 30 seconds. After that, grasp the test specimen with tweezers and transfer it to a container, and measure the mass of the test specimen after water absorption. Calculate the amount of water absorbed from the difference between the mass of the test specimen before water absorption and the mass of the test specimen after water absorption, and record it to one decimal place. Measure three times for samples from the same lot, and use the average value as the measured value. Multiply the measured value (amount of water absorbed) by 100 and divide by the basis weight of one set to convert it to the amount of water absorbed per basis weight.

[0026] The (oil absorption per unit basis weight) was measured as follows. The test environment was 23°C and 50% humidity, and the test specimen was cut to 100 mm in the vertical direction and 100 mm in the horizontal direction (±0.5 mm). The test specimen was kept as a single set, not as a sheet. First, the mass of the test specimen before oil absorption was measured. Next, a tray larger than the test specimen (for example, inner dimensions: 215 mm x 160 mm) was filled with 23°C salad oil (Nissin Salad Oil: manufactured by Nissin Oillio Group Ltd. (Type B viscosity at 23°C: 49 mPa·s)) to a depth of about 20 mm. The test specimen was spread out on a rigid flat mesh larger than the test specimen, lowered into the tray containing the salad oil, and immersed in the oil so that the test specimen was in contact with the liquid surface without being submerged. The flat mesh on which the test specimen was placed had an outer frame of wire measuring 120 mm x 120 mm and a 30 m wire mesh arranged within this outer frame. A mesh with an inner frame and handles for operation is used. Next, visually confirm that the salad oil has sufficiently permeated the surface of the test piece, raise the flat mesh straight up from the water surface, leave it still for 30 seconds, then grasp the test piece with tweezers and transfer it to a container, and measure the mass of the test piece after oil absorption. Calculate the amount of oil absorbed from the difference between the mass of the test piece before oil absorption and the mass of the test piece after oil absorption, and record it to one decimal place. Measure three times for samples from the same lot, and use the average value as the measured value. Multiply the measured value (amount of oil absorbed) by 100 and divide by the basis weight of one set to convert it to the amount of oil absorbed per basis weight.

[0027] MMD is a value measured as follows: MMD (variation in average coefficient of friction) is measured using a friction tester KES-SE manufactured by Kato Tech Co., Ltd. or an equivalent instrument with equivalent functionality. The measurement method involves moving the friction element 30 mm at a load of 200 gf and a speed of 1 mm / s while the contact surface of the friction element is in contact with the surface of the sample to be measured, and the effective measurement range is 20 mm, excluding the first and last 5 mm of movement. The sample to be measured is placed on the measuring stand and fixed in place by placing weights around its periphery to prevent movement. For example, a square-shaped weight that can be placed on the measuring stand to surround the measurement range is used. In this case, the weight of the weight can be approximately 130 g. The friction element is a 10 mm square piano wire sensor or an equivalent instrument that comes standard with the friction tester KES-SE manufactured by Kato Tech Co., Ltd. MMD is measured 10 times for each surface and the average value is taken. Measurements are taken 5 times each in the vertical and horizontal directions on both the front and back surfaces. The average value will be used as the MMD measurement value.

[0028] On the other hand, in this embodiment, it is desirable that the average difference in the height of the surface irregularities in the lateral direction of the kitchen paper is more than 10 μm and less than 110 μm, preferably more than 30 μm and less than 80 μm, and more preferably more than 40 μm and less than 50 μm. The above difference in the height of the surface irregularities in the lateral direction results in a suitable surface quality, making it easier to create the above-mentioned MMD in the vertical and horizontal directions. Note that the surface refers to both the front and back surfaces of one sheet or one set of kitchen paper.

[0029] The difference in height of surface irregularities in the lateral direction can be measured using the "One-Shot 3D Shape Measuring Machine VR-6000 (manufactured by Keyence Corporation)" (hereinafter also referred to as the "3D Microscope") and its equivalent (non-contact three-dimensional measuring instrument). The "3D Microscope" can measure the shape of an object from a striped projection image of the object displayed on a monochrome C-MOS camera using structured illumination light emitted from a light-emitting unit. In particular, the obtained striped projection image can be used to measure the height, length, angle, volume, area, etc. of any part. The software "VR-6000 Analysis Application" and its equivalent software can be used for observation, measurement, and image analysis of images obtained by the "3D Microscope". The measurement conditions are a high-magnification camera magnification of 40x, a field of view of 7.58 mm x 5.68 mm, and measurement mode set to full Auto. If there are recesses due to embossing, the line roughness measurement points should be in areas other than the recesses.

[0030] The height difference is determined by measuring line roughness. First, the height of each point in the image is displayed as a color image, and the presence and location of horizontal irregularities are visually confirmed by referring to the shading and color of the image. Next, line segments are drawn to intersect the horizontal irregularities that were visually confirmed, and the height profile curve of the line segment is obtained, and the slope is automatically corrected. In principle, the line segments intersecting the horizontal irregularities are drawn along the horizontal direction of the paper, but they can be adjusted within a range of ±5 degrees from the horizontal direction to avoid distortion of irregularities due to the characteristics of the crepe paper that makes up the kitchen paper, and to avoid overlapping crepe positions. In addition, one line segment is selected for each image to obtain the height profile curve. The length of the line segment is set to 1.0 to 1.4 mm. Next, in order to remove noise, a "contour curve" is obtained from the height profile curve, and the difference between the maximum and minimum values ​​of the "contour curve" is taken as the "height difference of irregularities". The "contour curve" is a curve obtained by removing surface roughness components with wavelengths shorter than λc:250 μm (where λc is the "filter that defines the boundary between roughness components and waviness components" as described in JIS B 0601 "3.1.1.2") from the height profile curve using a low-pass filter. The difference between the value at the position corresponding to the top of a convex area (maximum value) and the values ​​at the positions corresponding to the bottoms of the two concave areas on either side (minimum values) is measured, and the average of these is taken as the measured value. The value of the height difference of the lateral irregularities is the average value measured for five convex areas.

[0031] On the other hand, as shown in FIGS. 1 and 2, it is desirable that the kitchen paper according to the present embodiment has unevenness by embossing. In particular, a double embossing form in which a concave portion 31 is formed on one side and a convex portion 32 corresponding to the concave portion 31 is formed on the other side by embossing, and the sheets 30, 30 have a laminated structure in which the convex portion forming surfaces face each other is desirable. In the double embossing form, a gap is formed between the sheets, and the liquid absorption property and the liquid absorption amount of moisture and oil adhering to the surroundings of the kitchen such as food ingredients, tableware, and sink are improved. Further, due to the unevenness on the sheet surface, the scraping property of dust, dirt, and stains is improved, so that the convenience as the kitchen paper 11 is enhanced. As the double embossing form, as shown in FIG. 1, a laminated structure (Tip To Tip form) in which the convex portion 32 of one sheet 30 faces the convex portion 32 of the other sheet 30 may be used, or as shown in FIG. 2, the convex portion 32 of one sheet 30 faces a portion where the convex portion 32 of the other sheet 30 is not formed, and the convex portion 32 of the other sheet 30 faces a portion where the convex portion 32 of one sheet 30 is not formed (Nested form).

[0032] The area of one of the concave portions 31 formed in each sheet 30 is preferably more than 1.0 mm ２ and less than 2.0 mm ２ [[ID=�]]Further, the total area ratio of the concave portions 31 per one side of the kitchen paper 11 is preferably 10% or more. The area of the concave portion 31 is measured for any 10 concave portions, and the average value thereof is taken as the final area of the concave portion. When the area of one concave portion 31 and the total area of the concave portions 31 on one side are within the above ranges, it is particularly excellent in terms of the liquid absorption property and the liquid absorption amount of moisture and oil and the scraping property of dust, dirt, and stains. Further, since a sufficient number of convex portions are cross-linked between the sheets, it is also particularly excellent in improving the crushing of the kitchen paper roll 10. The upper limit value of the total area ratio of the concave portions 31 is not necessarily limited, but is at most 50%, preferably 25%, and particularly preferably 15%. Within this range, the balance between the portion where the concave portion 31 is formed by embossing and the rigidity is increased and the portion where the concave portion 31 is not formed and the rigidity is not increased becomes good.

[0033] In the kitchen paper 11 according to this embodiment, the shape of a single recess is not necessarily limited. It can be any suitable shape, such as a rectangle, circle, or ellipse. Multiple shapes may be mixed together. The pattern of the design formed by the multiple recesses is also not limited in this invention. It can be any suitable design considering aesthetic appeal.

[0034] The area of ​​the recess 31 can be measured using a Keyence Corporation VR-3200 one-shot 3D measuring microscope or an equivalent instrument with similar functionality, and the image analysis software "VR-H1A" or equivalent software with similar functionality. The measurement is performed under conditions of a magnification of 12x and a field of view of 24 mm x 18 mm. However, the magnification and field of view can be appropriately changed depending on the size of the emboss (recess). The specific measurement procedure involves using the above software to visually select one emboss (recess) 31 whose outline is clearly displayed to a measurable degree from the image shown in a planar view, and measuring the area inside the outline. In the case of the basis weight and roll length of the kitchen paper according to this embodiment, the recess 31 transferred to the sheet can be maintained without excessive collapse.

[0035] In the kitchen paper 11 according to this embodiment, the depth of the recesses 31 formed in each sheet 30 by embossing is not necessarily limited. Preferably, the sheet to be processed is embossed using an embossing roll in which the height of the protrusions for forming the recesses 31 in the sheet 30 is 0.20 mm to 0.55 mm, thereby creating a laminated structure.

[0036] Furthermore, in this embodiment, it is desirable that the kitchen paper 11 sheets 30, 30 are bonded together by an adhesive 33. Specifically, the adhesive may be applied to the entire surface of one sheet 30 or both sheets 30, 30 facing each other, and the sheets may be bonded together at the raised portions 32 created by embossing. Alternatively, the adhesive may be applied to the tops of the raised portions 32 created by embossing on one sheet 30 or both sheets 30, 30, and the sheets may be bonded together at the raised portions 32. In this case, the adhesive may be applied to only some of the raised portions 32, and the sheets 30, 30 may be bonded together by the adhesive applied to the tops of some of the raised portions 32. Because the sheets 30, 30 are bonded to each other, the sheets 30, 30 are less likely to shift, the convex portions 32 cross-linked between the sheets 30, 30 are less likely to be crushed, and the recessed portions 31 created by the embossing provide excellent moisture and oil absorption and absorption capacity, as well as the ability to scrape off dust, dirt, and grime.

[0037] The adhesive in this embodiment can be any known adhesive used in kitchen paper 11 having a laminated structure. Examples of such adhesives include hot melt adhesives, polyvinyl alcohol, starch, modified starch, carboxymethylcellulose, and the like. Furthermore, since the sheets constituting the kitchen paper are made of paper, the sheets can be weakly bonded to each other by applying water to the tops of the protrusions. Therefore, water or pure water can be used as the adhesive. A preferred adhesive is polyvinyl alcohol.

[0038] On the other hand, the constituent fibers in the kitchen paper 11 according to the present embodiment are not necessarily limited, but it is desirable that they be 100% by mass of pulp. In particular, in the case of 100% by mass of pulp, it is desirable that they be composed of pulp derived from coniferous trees (also referred to as N material) and pulp derived from broad-leaved trees (also referred to as L material). In this case, the ratio of L material to N material is desirably L material: 0 to 80%, and N material: 100 to 20%. The paper quality is easily adjusted to the range of the dry and wet tensile strengths, the value of (water absorption per unit basis weight) / (MMD), the value of (oil absorption per unit basis weight) / (MMD), and further the MMD in the longitudinal and transverse directions and the aspect ratio of MMD ((MMD in the longitudinal direction) / (MMD in the transverse direction)) according to the present embodiment. Examples of the pulp derived from coniferous trees (N material) include NBKP (coniferous kraft pulp) and NUKP (unbleached coniferous pulp). Examples of the pulp derived from broad-leaved trees (L material) include LBKP (broad-leaved kraft pulp) and LUKP (unbleached broad-leaved pulp).

[0039] The kitchen paper 11 according to the present embodiment desirably contains pulp fibers that are not unrefined. The beating degree of the papermaking raw material during production is not necessarily limited, but it is desirable to beat it so that the drop width of the Canadian standard drainage degree is 20 cc to 50 cc. The Canadian standard drainage degree of the papermaking raw material is desirably generally 500 cc or more. The paper quality is easily adjusted to the range of the dry and wet tensile strengths, the value of (water absorption per unit basis weight) / (MMD), the value of (oil absorption per unit basis weight) / (MMD), and further the MMD in the longitudinal and transverse directions and the aspect ratio of MMD ((MMD in the longitudinal direction) / (MMD in the transverse direction)) according to the present embodiment.

[0040] The kitchen paper according to the present embodiment can be in the form of a product in which a plurality of square or rectangular sheets are stacked and bundled, or in the form of a kitchen paper roll in which a strip-shaped kitchen paper is wound in a roll. In the form of a bundled product, it is desirable that the bundle be a pop-up type bundle in which when one sheet on the upper surface is taken out, the next sheet is pulled out.

[0041] The kitchen paper 11 according to this embodiment is particularly suitable for the form of the kitchen paper roll 10. Specifically, as shown in FIG. 3, it is a product in which a strip-shaped kitchen paper 11 is wound around a paper tube 12. Although not limited, the winding length is preferably 10 to 30 m, and the number of cuts is preferably 50 to 160 cuts. With this winding length and number of cuts, it can be said that it is a sufficient product as a kitchen paper roll. The number of cuts is the number of sheets that can be separated by perforations arranged at predetermined intervals in the longitudinal direction of the kitchen paper, and together with the winding length, it serves as a guide for the period and number of times that a user can use it. For the kitchen paper roll according to this embodiment, particularly, the winding length is preferably 10 to 24 m, and the number of cuts is preferably 50 to 120. With this winding length and number of cuts, it can be used about 1.5 to 2 times that of normal products, and consumers can recognize that it has excellent storage and stockpiling properties. The number of cuts is the number of sheets when separated by perforations.

[0042] The winding diameter (diameter) L3 of the kitchen paper roll 10 according to this embodiment is 90 to 130 mm, which is a general winding diameter, and the transportation cost can be the same as before. The winding diameter (diameter) is a value measured using a diameter rule manufactured by Muratec KDS Co., Ltd. or a comparable machine having an equivalent function. Also, it is desirable that the height (width) L2 of the kitchen paper roll 10 according to this embodiment is 200 to 235 mm, and the inner diameter (core diameter) L4 is 35 to 45 mm.

[0043] Furthermore, the winding hardness of the kitchen paper roll 10 according to this embodiment is set to be 0.4 kgf or more and 1.6 kgf or less. Within this range of winding hardness, sufficient absorbency can be achieved. Here, the winding hardness is a value measured by winding a diameter rule (manufactured by Muratec KDS Co., Ltd.) and its equivalent machine around the central portion between the end faces of the kitchen paper roll in the circumferential direction, and using a push-pull gauge (manufactured by IMADA Co., Ltd.) and its equivalent machine to measure the force required to subtract three graduations from the Π rule graduations.

[0044] Next, examples and comparative examples relating to the kitchen paper and kitchen paper roll of the present invention were prepared and their physical properties were measured. The physical properties and composition of the kitchen paper and kitchen paper roll relating to each example are shown in Table 1 below. The measurement method is as described above. Regarding the difference in height of the unevenness, in the comparative example, it was not possible to measure the unevenness in the lateral direction because no measurable unevenness could be visually confirmed.

[0045] In Examples 1, 2, and Comparative Example 1, the embossed laminated structure is of the Tip-to-Tip type, and the embossed pattern is the same. In Examples 3 to 7 and Comparative Examples 2 to 6, the embossed laminated structure is of the nested type, and the embossed pattern is the same. In Examples 1 to 4 and Comparative Examples 1 to 3, the winding length was 10 m. In Example 5 and Comparative Example 4, the winding length was 14 m. In Example 6 and Comparative Example 5, the winding diameter was 20 m. In Example 7 and Comparative Example 6, the winding length was 24 m. Examples 5 to 7 and Comparative Examples 4 to 6 are so-called long-length specifications. In addition, each example and comparative example was wound to a winding diameter within a general range, and all are within the general range of 101 to 120 mm.

[0046] Furthermore, each example and comparative example was manufactured without applying a wet crepe and without using a fabric press papermaking technique, but by a papermaking technique that applies a dry crepe using a doctor blade. In addition, the comparative examples used a doctor blade that tends to increase only the vertical MMD while not increasing the lateral MMD. Comparative Examples 1, 4, 5, and 6 used the same doctor blade, while Comparative Examples 2 and 3 used different doctor blades. Also, Examples 1 to 8 used a doctor blade that tends to increase the lateral MMD. In addition, Examples 1, 2, 5, and 6 used the same doctor blade, Examples 4 and 7 used the same doctor blade, while Example 3 used a different doctor blade. All doctor blades are commercially available products.

[0047]

[0048] As shown in Table 1, Examples 1 and 2 have lower basis weights than Comparative Example 1, but their water absorption and oil absorption are equivalent to or better than those of Comparative Example 1. In other words, absorbency is improved without increasing the basis weight. Comparing Examples 3 and 4, which are nested in a nested format, with Comparative Examples 2 and 3, Example 3, which has a lower basis weight than Comparative Examples 2 and 3, also shows improved absorbency, while Example 4, which has a similar basis weight, also achieves equivalent or better absorbency.

[0049] Furthermore, comparing Example 5 with Comparative Example 4, Example 5 exhibits superior absorbency, such as oil absorption and water absorption, despite having a lower basis weight than Comparative Example 4. Similarly, comparing Example 6 with Comparative Example 5, Example 6 exhibits almost the same absorbency, such as oil absorption and water absorption, as Comparative Example 5, despite having a lower basis weight.

[0050] Furthermore, comparing Example 7 with Comparative Example 6, Example 7 exhibits superior absorbency, including oil absorption and water absorption, despite having a slightly lower basis weight than Comparative Example 6. It should be noted that Examples 5 to 7 were long-length specifications, and the results indicated they are also suitable for long-length applications.

[0051] As described above, the kitchen paper and kitchen paper roll according to the present invention can improve absorbency without increasing the basis weight, and are suitable for products with long rolls or a large number of sheets.

[0052] 10...Kitchen paper roll, 11...Kitchen paper, 12...Paper tube, 30...Sheet, 31...Recess, 32...Convex part, 33...Adhesive, L2...Width of kitchen paper roll, L3...Diameter of kitchen paper roll winding, L4...Diameter of kitchen paper roll paper tube.

Claims

1. A kitchen paper characterized by having a paper thickness of 1.5 to 4.5 mm / 5 sets, a dry tensile strength in the longitudinal direction of 1000 to 3000 cN / 25 mm, a dry tensile strength in the transverse direction of 300 to 800 cN / 25 mm, a wet tensile strength in the transverse direction of 80 to 250 cN / 25 mm, a value of (water absorption per unit basis weight) / (MMD) of 0.2 to 0.8, and a value of (oil absorption per unit basis weight) / (MMD) of 0.2 to 0.

8.

2. The kitchen paper according to claim 1, wherein the vertical MMD is 5 to 30, the horizontal MMD is 7 to 60, and the aspect ratio of the MMD ((vertical MMD) / (horizontal MMD)) is 0.1 to 1.

0.

3. The kitchen paper according to claim 1 or 2, wherein the kitchen paper is two-ply and has a laminated structure in which sheets with embossed irregularities are laminated with their convex surfaces facing each other.

4. A kitchen paper roll obtained by winding the strip-shaped kitchen paper described in claims 1 to 3 into a roll, characterized in that the winding length is 10 to 30 m, the winding diameter is 90 to 130 mm, and the winding hardness is 0.4 kgf or more and 1.6 kgf or less.

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