WO2014049840A1

WO2014049840A1 - Hand towel and method for manufacturing same

Info

Publication number: WO2014049840A1
Application number: PCT/JP2012/075117
Authority: WO
Inventors: 康伸大岡; 大篭　幸治
Original assignee: 日本製紙クレシア株式会社
Priority date: 2012-09-28
Filing date: 2012-09-28
Publication date: 2014-04-03
Also published as: JPWO2014049840A1; JP5468686B1

Abstract

[Problem] To provide a hand towel, which has an excellent water absorbing capacity even having a low basis weight and shows a high strength and a good feeling of use, and a method for manufacturing the same. [Solution] A hand towel which contains pulp as the main component and comprises a set consisting of one sheet or two or more stacked sheets, wherein: the set has a basis weight of 15-45 g/m²; when the set consists of one sheet, the water absorption rate is 60-230 water-g/m², and when the set consists of two or more sheets, the water absorption rate is 100-500 water-g/m²; and when the set consists of one sheet, the water absorption degree in accordance with old JIS-S3104 law is 25.0 sec/0.1 mL or below, and when the set consists of two or more sheets, the water absorption degree in accordance with the same is 3.0 sec/0.1 mL or below.

Description

Hand towel and method for manufacturing the same

The present invention relates to a hand towel and a manufacturing method thereof.

In offices and buildings, disposable paper towels are widely used for wiping after washing hands. This hand towel is required to have high water absorption, high bulk, and high strength even when wet. However, if the basis weight is increased in order to improve water absorption, there is a problem that the cost increases. On the other hand, if the strength becomes too high, the hand towel becomes hard and the touch and feeling of use may be lowered.

As a method of obtaining a paper product having a bulky feeling and a soft texture, a softening agent (cationic agent) is added to a raw material pulp having a fiber length and fiber roughness within a predetermined range, and then creping is performed. A method is known in which a bulky crepe paper is obtained by suppressing interfiber bonding of pulp fibers (Patent Document 1).
Further, as a mechanical treatment for obtaining a high-bulk paper product, a method TAD (through air drying) method (patent document 2) is a method in which wet paper is air-dried without press-dehydrating in the paper-making process. ), And a method of performing uneven treatment on the wet paper web between the wet paper formation and the drying process.
Furthermore, there is a method of mechanically treating the web after paper making by embossing or the like. Further, these methods may be combined.
However, in the case of the internal addition method using the softening agent described above, the chemical cost is high, and the fiber-to-fiber bond of the pulp is lowered, so that the strength of the web is lowered, the generation of paper dust is further increased, and the water absorption is lowered. There is a problem.
Further, in the case of the above TAD method, the cost of the drying energy becomes enormous. Furthermore, in the method of performing unevenness treatment after paper making, the bond between fibers and the paper layer structure are broken, the web strength is lowered, or the apparent bulk of the web is increased, but the paper layer bulk (caliper) of the web itself is increased ( There is a problem that it is difficult to produce a soft feeling).

On the other hand, in the paper making of conventional paper products, the wet paper web is dehydrated by pressing it with a Yankee dryer at one or two roll press nips through a felt, and further attached to a Yankee dryer (cylinder) and then dried. Creping (crease) is performed when the web is peeled off from the dryer. Moreover, in a press part, like a double felt machine, it presses with the top and bottom rolls of a wet part, and dehydrates, and it may press against a Yankee dryer by a roll press nip after that.
However, there is a problem that the web becomes relatively low bulk due to the pressing to the Yankee dryer. Even if the bulking agent described above is added to the pulp raw material to suppress the bulk drop due to creping, only a bulky effect of about 3 to 5% can be obtained, while the strength is significantly lowered.
In addition, the TAD method described above is a technique in which the final drying and creping are performed with a Yankee dryer and dehydrated with a vacuum, and preliminarily dried with a ventilating dryer. And a high bulk web is obtained. However, since the TAD method removes moisture equivalent to press nip dehydration by ventilation heat, it is said that about twice as much drying energy is required as compared with the conventional roll press nip method.

Therefore, as a method of performing high bulk processing in the wet paper process without using the TAD method, a method of adjusting pressure dehydration by a wide press nip called a shoe press method has been proposed (Patent Document 3). The shoe press method can obtain a higher bulk and softness than the conventional roll press nip method, but cannot obtain a higher bulk than the TAD method.
Furthermore, as a method for solving these problems, a paper machine called a fabric press system has been developed (Patent Document 4). The fabric press method follows the conventional press technology, but is provided with unevenness on the web by means of an uneven belt or fabric simultaneously with dewatering. This dewatering and roughening is performed in one or more press nips while the wet web is fed from the felt to the roughening belt, and then the web is transported to a Yankee dryer and dried.
According to the fabric press method, a high bulk equivalent to the TAD method can be obtained while the drying energy is equivalent to that of the conventional roll press nip method.

The structure of the web by the fabric press method is not a woven fabric, but forms a three-dimensional pattern similar to the woven fabric. This is considered because web unevenness is performed as follows. That is, during the pressing process, the fibrous network fills the three-dimensional pattern (pattern) of the concavo-convex belt, but at that time, the three-dimensional pattern of the concavo-convex layer forms a wet fibrous web. Is granted. The wet fibrous webs are moveable relative to each other, so that they take a new position and orientation relative to each other due to the elastic compression of the press felt. Press felt presses the wet fibrous web against the three-dimensional pattern of the textured belt, thereby increasing bulk and softness with the same basis weight and an improved structure.
The bulk of the web is then maintained uncompressed by receiving a fibrous network (network) in cavities in the belt structure while dewatering in the press nip.

JP 2006-97191 A JP-A-8-3890 JP-A-6-158578 Special table 2001-521999 gazette

However, even if the technique described in Patent Document 4 is used, there is a problem that the water absorption is reduced when the basis weight is lowered.
Accordingly, an object of the present invention is to provide a hand towel that is excellent in water absorption even when the basis weight is low, and that is excellent in strength, touch and feeling of use, and a method for producing the same.

In order to solve the above-mentioned problems, the hand towel of the present invention is composed of a set in which pulp is a main component and one sheet or two or more sheets are stacked, and the basis weight of the one set is 15 to 45 g / m ² . The water absorption when the one set is composed of one sheet is 60 to 230 water-g / m ² , and the water absorption when the one set is composed of two or more sheets is 100 to 500 water. -g / m ² and the water absorption specified in the old JIS-S3104 method is 25.0 seconds / 0.1 mL or less when the one set is composed of one sheet, and the one set is 2 When it is composed of at least one sheet, it is 3.0 seconds / 0.1 mL or less.

The height difference of the surface irregularities is preferably 100 to 600 μm.
The area ratio of the recesses on the surface is preferably 2 to 12%.
When the tissue softness measuring device TSA is used to push the sample of the hand towel placed on the specimen table from above with a pushing pressure of 100 mN and 600 mN without rotating the bladed rotor, the pushing pressure of 100 mN and 600 mN respectively. It is preferable that the measured value of rigidity (D), expressed by the amount of deformation displacement in the vertical direction of the sample in between, is 2.0 to 3.2 mm / N.
Using the tissue softness measuring device TSA, the bladed rotor was pushed in from the top as a pushing pressure of 100 mN on the sample of the hand towel placed on the sample table, and then rotated at a rotation speed of 2.0 (/ sec). When the vibration is measured by a vibration sensor, the spectrum with the maximum peak intensity (TS750) of 16-50 dBV ² rms from the low frequency side automatically acquired by software on the TSA and including 6500 Hz The maximum peak intensity (TS7) is preferably 19 to 40 dBV ² rms.
The specific volume is preferably 4.5 to 9.0 cm ³ / g.
It is the square root of the product of the tensile strength WMDT in the longitudinal direction when wet according to the former JIS S3104 and the tensile strength WCDT in the lateral direction when wet of the hand towel (WMDT × WCDT) ^1/2 (WGMT) Is preferably 2.0 to 6.0 N / 25 mm.

The method for producing a hand towel of the present invention is the above-described method for producing a hand towel, in which an uneven fabric is pressed against a wet paper web to perform unevenness simultaneously with dehydration, and then the web is dried.

According to this invention, even if the basis weight is low, it is possible to obtain a hand towel that is excellent in water absorption, and further excellent in strength, touch and usability.

It is a figure which shows an example of the image acquired with the shape measurement laser microscope. It is a figure which shows an example of the height profile of the line segment L which crosses the observation visual field of an image. It is a figure which shows the image which took in the hand towel surface with the image scanner. It is a figure which shows the measurement principle of tissue softness measuring apparatus TSA. It is a figure which shows an example of the analysis result of the vibration frequency of the paper sample sample by TSA. It is a figure which shows the measuring method of the rigidity D of the paper sample sample by TSA. It is a figure which shows an example of the manufacturing apparatus of the hand towel web which concerns on embodiment of this invention. It is a figure which shows the measuring method of water absorption.

Embodiments of the present invention will be described below.
The hand towel according to the embodiment of the present invention is composed of a set of pulp as a main component and one or two or more sheets stacked, and the basis weight of one set is 15 to 45 g / m ^2. Water absorption when one sheet (1 ply) is 60 to 230 water-g / m ² , and water absorption when one set is composed of two or more sheets (2 plies or more) is 100 to 500 water-g / m ² and the water absorption specified in the old JIS-S3104 method is 2.3 to 25.0 seconds / 0.1 mL for 1 ply and 0.0 for 2 plies or more. ~ 3.0 seconds / 0.1 mL.

When the basis weight of one set is less than 15 g / m ² , the strength and absorbency are lowered, and when it exceeds 45 g / m ² , it becomes hard and inferior in softness (hand). The basis weight is preferably 15 to 40 g / m ² , more preferably 15 to 35 g / m ² .

60 water-g / m less than ² when the water absorption is 1-ply, or the case of two-ply or more is less than 100water-g / m ^2, the not suitable for practical use low water absorption.
On the other hand, beyond the 230 water-g / m ² when water absorption is 1-ply, or in the case of two-ply or more than 500water-g / m ^2, although the water absorption amount is large, and the hand towel becomes stiffer Softness (feel and feel) is inferior.
In the case of 1 ply, the water absorption is preferably 80 to 230 water-g / m ² , and more preferably 100 to 230 water-g / m ² . In the case of 2 plies or more, the water absorption is preferably 200 to 500 water-g / m ² , and more preferably 250 to 500 water-g / m ² .
The amount of water absorption is measured as shown in FIG. First, a set of sheets collected from a hand towel is cut using a square template having a size of 7.62 cm (3 inches), and a rectangular test piece having a side of 7.62 cm is prepared. The mass of the test piece before water absorption is measured with an electronic balance. The test piece is set in a holder (a jig that fixes three points of the test piece, and the jig is made of a metal that does not absorb moisture).
Next, 1 cm of distilled water is put into a commercially available vat, and the test piece set in the holder is immersed in the distilled water of the vat for 2 minutes. After immersion for 2 minutes, the test piece is taken out of the water together with the holder, and a band 210 is attached to one corner 200d of the test piece 200 as shown in FIG. The band 210 is obtained by cutting a 1ply general hand towel product into a size of 2 mm wide × 15 mm long and affixing it to a 6 mm portion from the corner 200 d of the test piece toward the center. Next, the holder and the test piece 200 are hung on a stick installed in an empty water tank with the corner 200a facing the corner 200d facing upward, and the lid of the water tank is closed and left for 30 minutes. Thereafter, the holder 220 and the test piece 200 are taken out of the water tank, the band 210 and the holder 220 are removed, and the mass of the test piece 200 is measured with an electronic balance. The amount of water absorption (Water-g / m 2) per 1 m 2 of the test piece is calculated from the change in mass of the test piece 200 before and after being immersed in water. Further, the water absorption amount (Water-g / m2) / (g / m2) = Water-g / g is calculated by dividing the water absorption amount (Water-g / m2) by the basis weight of the test piece. The measurement was performed 5 times for each sample, and the average value was adopted.
This measurement is performed in accordance with JIS-P8111 method at a temperature of 23 ± 1 ° C. and a humidity of 50 ± 2%. Distilled water is kept at 23 ± 1 ° C.

The smaller the water absorption specified in the old JIS-S3104 method, the better. However, it is not possible to measure a water absorption of 1.0 second or less. I will consider it. Therefore, the lower limit of the water absorption is 0.0 second / 0.1 mL in the case of 1 ply in the measurement, and 0.0 second / 0.1 mL in the case of 2 plies or more. However, since it is generally difficult to make it less than 2.3 seconds / 0.1 mL in the case of 1 ply, the lower limit of water absorption in the case of 1 ply may be 2.3 seconds / 0.1 mL.
On the other hand, if the water absorption is more than 25.0 seconds / 0.1 mL in the case of 1 ply, or more than 3.0 seconds / 0.1 mL in the case of 2 plies or more, the water absorption is slow and not suitable for practical use. The water absorption is defined in the old JIS-S3104 method, and “0.1 mL” is the amount of water dripped onto the hand towel.
In the case of 1 ply, the water absorption is preferably 2.3 to 20.0 seconds / 0.1 mL, and more preferably 2.3 to 15.0 seconds / 0.1 mL. The water absorption in the case of 2 plies or more is preferably 0.0 to 2.5 seconds / 0.1 mL.

The hand towel may be made of 100% wood pulp and may contain waste paper pulp and non-wood pulp. In order to obtain the target quality, it is preferable to use wood pulp of NBKP: LBKP = 10: 90 to 90:10 (mass ratio) as a raw material, and a more preferable range is NBKP: LBKP = 20: 80 to 80: 20. A more preferable range is NBKP: LBKP = 30: 70 to 70:30. Pulp produced from Eucalyptus eucalyptus represented by Eucalyptus grandis and Eucalyptus globulus is preferred as the grade of LBKP. Moreover, a waste paper pulp mixing | blending can also be 100 mass%. Waste paper pulp has a large variation in quality, and as the blending ratio increases, the quality of the product, particularly the softness, is greatly affected. Therefore, it is desirable to blend 60% by weight or less with respect to the wood pulp.
In addition, in order to ensure an appropriate strength for the hand towel, raw materials can be blended by ordinary means, and the strength can be adjusted by beating the pulp fiber. As the beating to obtain the target quality, 0 to 300 ml, more preferably 0 to 250 ml, and still more preferably 50 to 250 ml of filtered water with respect to commercially available virgin pulp at a Canadian standard freeness measured by JIS P8121. Reduce the degree.
Details of the hand towel web manufacturing method will be described later.

In the hand towel according to the embodiment of the present invention, the average value of the height difference of the unevenness on the surface is 100 to 600 μm, preferably 100 to 550 μm, more preferably 150 to 500 μm, and the average value of the area ratio of the recesses on the surface is 2 to It is preferable that the amount is 12%, preferably 3 to 12%, more preferably 4 to 12%, because the above-described water absorption and water absorption can be obtained with certainty.
In addition, the surface means both sides facing the outside of the product (that is, the surface opposite to the overlapping surface of the sheets) if the hand towel is a product of 2 ply or more, and if it is a 1 ply product, Means both sides.
The height difference of the surface irregularities is measured using a shape measuring laser microscope. The shape measurement laser microscope scans a laser light source, which is a point light source, into pixels obtained by dividing an XY plane in an observation field into a plurality of pixels through an objective lens, and detects reflected light for each pixel with a light receiving element. . Then, the objective lens is driven in the height (Z-axis) direction, and the height information and the reflected light amount are detected with the Z-axis position having the highest reflected light amount as a focal point. By repeating the scanning in this way, an ultra-deep light amount image and a high / low image (information) focused on the whole can be obtained. Since the laser light source is a pinhole confocal optical system, the measurement accuracy is high.
As the shape measurement laser microscope, the product name “Ultra Deep Color 3D Shape Measurement Microscope VK-9510” manufactured by KEYENCE can be used. The product name “VK Viewer” can be used as the observation / measurement software. The measurement conditions are 200x magnification (standard objective lens uses 10x magnification), the measurement mode is color ultra-deep, the gain is adjusted automatically by Auto setting, the measurement pitch is 1μm, the distance (range in the Z-axis direction) Set (μm) to be equal to or greater than the sample paper thickness and measure. Note that the measurement is performed at a location other than the portion mechanically embossed in a process other than the paper machine (for example, an interfolder).

Thereafter, a height profile is acquired from the obtained image using image analysis software (VK Analyzer). First, a line segment L that crosses the observation visual field of the image shown in FIG. 1 is visually drawn so that a white portion and a black portion are adjacent to each other in the image. Since the white portion in FIG. 1 corresponds to the convex portion and the black portion corresponds to the concave portion, the line segment L may be determined so as to cross the portion where the white strong portion and the black strong portion are adjacent to each other. The height profile is acquired by selecting one line segment L for each image. The length of the line segment L is 1.0-1.4 mm. Then, a height profile is obtained as shown in FIG. Here, the height profile in FIG. 2 is a (measurement) cross-sectional curve S representing the actual unevenness of the sample surface, but noise (a fiber lump is present on the surface of the hand towel, or the fibers extend in a beard shape). In addition, it is necessary to remove such a noise peak when calculating the height difference of the unevenness.
Therefore, the “contour curve” W is calculated from the cross-sectional curve of the height profile, and the difference between the maximum value MAX and the minimum value MIN of the “contour curve” is defined as the “concave height difference”. Here, the “contour curve” is λc: 250 μm from the cross-sectional curve (where λc is a “filter that defines the boundary between roughness component and waviness component” described in JIS-B0601 “3.1.1.2”). It is a curve obtained by removing the surface roughness component of the above by a low-pass filter.
2 is based on the height of the pedestal on which the sample is placed on the shape measuring laser microscope. In the line segment L, for example, when there is one peak (convex portion) and two valleys (concave portions) adjacent to it, the smallest MIN of the concave portion is used. When there are two peaks (convex parts), the maximum convex MAX is used.
As described above, the field of view of the height profile (length of L) is 1.0-1.4 mm, and surface embossing can be sufficiently avoided during measurement.

The area ratio of the recesses on the surface is obtained by performing image analysis on the surface of the hand towel, considering dark portions below a predetermined threshold as recesses, and calculating the area ratio.
Specifically, the surface of the hand towel is captured as image data as shown in FIG. 3 by a commercially available image scanner (for example, Epson GT-X770), and a predetermined image analysis apparatus (for example, Nippon Paper Unitech) The area ratio of the dark part below a predetermined threshold is obtained under the conditions of a resolution of 800 dpi and a scan area of 6 cm × 6 cm. Here, the above threshold is set to 98% close to the white side when black is 0 bits and white is 255 bits, and each dark part (shadow part) obtained is treated as particles (contamination). The particle diameter (equivalent circle diameter) (μm) is measured. After that, for particles having a particle size of 200 to 999 μm, the area of each particle was integrated and converted to the area ratio of dark parts (recesses) per 1 m ^{2 of} image area (for example, particles having a measurement area of 0.0036 m ^{2 and} 200 to 999 μm) If the integrated area is 500mm2, the area ratio (%) is 500mm2 ÷ 0.0036m2 x 100 = 13.9%).
In measuring the area ratio, a hand towel sample is placed with one side of the hand towel along one side of the scanner so that no wrinkles, perforations, folds, or the like enter the sample, and image data is captured. Next, one side of this hand towel is rotated by 90 ° C. with respect to the scanner, and each image data is taken in (four image data in total). This operation is repeated twice, and a total of 8 pieces of image data are captured. Further, the same operation is performed 8 times on the other surface of the hand towel sample. The 16 image data of the two surfaces (both sides) of the product thus obtained are subjected to the image analysis described above, the area ratio of the dark part (concave part) is measured, and the average value of these 16 area ratios Is adopted.
If you cannot secure a 6cm x 6cm scan area (0.0036m2), such as a perforation or crease in the hand towel sample, the measurement area to be measured at one time may be reduced. Increase the number of measurement points so that the measurement area is at least 0.0036m2. For example, if two points of 3 cm × 6 cm (0.0018 m 2) are measured, the measurement area becomes 0.0036 m 2.

When the height difference of the unevenness and the area ratio of the recesses are in the above ranges, moderate unevenness is generated on the surface of the hand towel, and water is easily absorbed even if the basis weight is low.
On the other hand, if the height difference of the unevenness and the area ratio of the recesses are less than the above range, the unevenness of the surface of the hand towel becomes low and it becomes difficult to absorb water, and the water absorption amount may be less than the above range.
If the height difference of the unevenness and the area ratio of the recesses exceed the above range, it becomes easy to absorb water, but the smoothness (hand feeling and feeling of use) of the hand towel may be inferior.
In addition, as an example of the method of managing the height difference of the unevenness and the area ratio of the recessed portion within the above range, it is possible to press the uneven fabric described later against the wet paper web and perform unevenness simultaneously with dehydration.
Also, hand towels may be mechanically embossed after paper making in a process other than the paper machine (for example, an interfolder). Since the size of these embosses (the height difference of the unevenness and the period of the unevenness) is as large as several millimeters, the effect of improving the water absorption and the amount of water absorption hardly occurs.

When the hand towel according to the embodiment of the present invention is measured by a tissue softness measuring apparatus TSA (Tissue Softness Analyzer), the maximum peak of the first spectrum from the low frequency side automatically acquired by software on the TSA is obtained. The strength (TS750) is 16 to 50 dBV ² rms, preferably 16 to 45 dBV ² rms, more preferably 16 to 40 dBV ² rms. When TS750 is higher than 50 dBV ² rms, the smoothness is inferior, and when TS750 is lower than 16 dBV ² rms, only the smoothness is prominent, and a good tactile sensation may not be obtained.
Further, the intensity (TS7) of the maximum peak of the spectrum including 6500 Hz obtained automatically by software on the TSA is 19 to 40 dBV ² rms, preferably 19 to 36 dBV ² rms, more preferably 19 to 30 dBV ^2. rms. When TS7 is higher than 40 dBV ² rms, sufficient softness may not be obtained, and when TS7 is lower than 19 dBV ² rms, only softness may stand out and good tactile sensation may not be obtained.

In addition, when the tissue softness measuring device TSA is pressed into the hand towel sample placed on the sample table from above with a pressing force of 100 mN and 600 mN without rotating the bladed rotor, the pressing pressure is 100 mN and 600 mN, respectively. The measured value of the stiffness (D), expressed by the amount of deformation displacement in the vertical direction of the sample in between, is 2.0 to 3.2 mm / N, preferably 2.4 to 3.2 mm / N, More preferably, it is 2.5 to 3.2 mm / N. When the D measurement value is lower than 2.0 mm / N, the overall flexibility of the hand towel is inferior, and when it is higher than 3.2 mm / N, the flexibility is too conspicuous and the overall balance may be lacking.

Here, as shown in FIG. 4, the tissue softness measuring apparatus TSA 210 performs vibration analysis on vibration data detected by various sensors when the rotated bladed rotor 204 is pressed on the paper sample (sample) 206. By parameterizing (TS value), the softness of the paper (feel) is quantitatively evaluated. The product name of Emtec Electronic GmbH (Germany is Japan Luft Co., Ltd.) It is.
For specific measurement using TSA, (i) Install sample 206 (sample processed into a circle with a diameter of about 112.8 mm using emtec sample punch) to cover the circular sample stage 205 from the outside. The outer periphery of the sample 206 is held by the sample fixing ring 208. (ii) After the bladed rotor 204 is pushed from above the sample 206 with a pushing pressure of 100 mN, the rotor 204 is rotated at a rotation speed of 2.0 (/ sec). (iii) The vibration of the sample table 205 is measured by the vibration sensor 203 installed in the sample table 205, and the vibration frequency is analyzed. (iv) Next, when the indentation pressure is 100 mN and 600 mN, the amount of deformation (mm / N, rigidity D) in the vertical direction when the sample 206 is deformed without rotating the rotor 204 is measured. By the procedures (i) to (iv), the elements (smoothness, suppleness, volume) of the overall hand feel value of the hand towel can be quantified. The measurement is repeated 5 times for each sample and averaged. In addition, the front and back means both sides facing the outside of the product if the hand towel is a 2ply product (that is, the surface opposite to the overlapping surface of the sheets), and both sides of a single sheet if the product is a 1ply product.
The sample stage 205 is installed on the base plate 201, and a force sensor 202 is disposed between the sample stage 205 and the base plate 201. Then, the pushing pressure of the bladed rotor 204 is controlled by the detection value of the force sensor 202. The bladed rotor 204 is rotated by a motor 209.
In addition, emtec measurement system is used as software for analyzing vibration and parameterizing (TS value). This software is equipped with various algorithms (for example, Base Tissue, Facial, TP, etc.), TS7, TS750, D are automatically acquired on the software, and these TS7, TS750, D, basis weight, thickness The HF (hand feel) value is calculated according to the type of various algorithms from the Ply number and the like. In the present invention, only the TS7, TS750, and D are defined, not the HF values, and any algorithm may be used as long as the above measurement conditions are satisfied. The values of TS7, TS750, and D depend on the algorithm type. It will not change.

FIG. 5 shows an example of the analysis result of the vibration frequency of the paper sample sample by TSA. The intensity of the maximum peak A of the first spectrum from the low frequency side is TS750, and the intensity of the maximum peak B of the spectrum including 6500 Hz (around 6500 Hz) is TS7. The maximum peak B is usually located at about 6500 Hz.
FIG. 6 shows a method of measuring the stiffness D of a paper sample sample by TSA.

The vibration frequency of the paper sample sample depends on the paper structure and the number of rotations of the rotor 4, and the amplitude (spectrum intensity) depends on the height of the paper structure such as the height of the crepe. TS750 which is the first peak of the spectrum (A in FIG. 5) represents smoothness and roughness. On the other hand, the frequency at which TS7 appears (in the range of 5000 to 8000 Hz, usually around 6500 Hz) is the resonance frequency of the rotor 4. Due to vibration. The rigidity D correlates with the rigidity (tensile strength) of the paper.
The lower the TS7 value, the better the soft feeling (surface softness and bulk softness), and the lower the TS750 value, the better the smoothness. Moreover, the greater the value of D, the more flexible.
Further, based on the functions of TS7, TS750, and D, a comprehensive hand feel value (HF value) can be calculated.
For example, by setting a function of (HF value) = A × (TS7) + B × (TS750) + C × (D) + α, the total hand feel value can be objectively (quantitatively) quantified. Here, A, B, C, and α are coefficients. By appropriately setting these coefficients, softness and smoothness corresponding to the factors constituting the hand feel value (that is, TS7, TS750, and D, respectively). , Stiffness) weighting can be adjusted to match the actual softness sensory evaluation.
When A and B are negative values and C is a positive value, the larger the hand feel value, the better the overall softness.

The specific volume of the hand towel is preferably 4.5 to 9.0 cm ³ / g, and more preferably 5.0 to 9.0 cm ³ / g. When the specific volume is less than 4.5 cm ³ / g, the soft feeling is poor and the softness (texture) may be inferior. On the other hand, when the specific volume exceeds 9.0 cm ³ / g, the bulk (bulkness) becomes high, but the smoothness is inferior and the smoothness (tactile feel) may be deteriorated.
Further, the WGMT of the hand towel is preferably 2.0 to 6.0 N / 25 mm, and more preferably 2.5 to 6.0 N / 25 mm. If WGMT is less than 2.0 N / 25 mm, it may be easily shaken and not suitable for practical use. When WGMT exceeds 6.0 N / 25 mm, it becomes hard and softness may be impaired.
In addition, WGMT of a set of hand towels is based on the former tensile strength WMDT (Wet Machine Direction Tensile strength) when wet and the transverse tensile strength WCDT (Wet Cross Direction Tensile when wet) based on the former JIS S3104. It is the square root of the product with (strength) and is represented by (WMDT × WCDT) ^1/2 (WGMT: Wet Geometric Tensile Strength).

The hand towel of the present invention is formed by stacking hand towel webs in a single ply or multiple plies (preferably 1 to 3 plies), cutting them into sheets of a predetermined size, and folding them in C so that they can be taken out continuously. It can be manufactured by stacking each other to a predetermined number. Moreover, this laminated body can be stored in a polypack or a box.

Next, the manufacturing method of the hand towel web which concerns on embodiment of this invention is demonstrated using FIG. FIG. 7 shows an example of a hand towel web manufacturing apparatus 50.
The apparatus 50 shown in FIG. 7 is a fabric press type paper machine, and can produce the web 103 with the unevenness only by the pressing means without using the ventilation drying (TAD) equipment for preliminary dehydration. The apparatus 50 includes a wet part 2 for forming a continuous web, a press part 3 for dewatering the web to be patterned or uneven, and a drying part 4 for finally drying the web.

The wet section 2 forms a wet paper in the form of a crescent former, a head box 6 for supplying a stock made of fiber and water to the forming area, a forming felt 8 for dehydrating a part of the water of the web, and the forming. It has a wire 9, a plurality of guide rolls 10, and a forming roll 7.
The head box 6 discharges a paper jet at a molding portion 5 between the forming wire 9 and the forming felt 8. The forming wire 9 has an endless loop shape, travels around the plurality of guide rolls 10 and the forming roll 7, and contacts the forming felt 8 with the forming roll 7. Accordingly, the stock discharged to the position 5 is dehydrated by the forming wire 9 to form the fibrous web 101, and the fibrous web 101 is conveyed to the press unit 3 by the forming felt 8. The forming felt 8 is also in the form of an endless loop that travels around a plurality of guide rolls 18.
In addition, the shaping | molding part 5 can also be used as a suction breast roll former.

The press unit 3 includes a main press 11 and a textured fabric 14, and the main press 11 includes a first press element 12 and a second press element 13. The first and second

pressing elements

12, 13 are pressed together to form a press nip N1 therebetween. In the example of FIG. 7, the main press 11 is a roll press and forms a twin roll in which the first and

second press elements

12 and 13 face each other. And the 1st press element (roll) 12 is located in the loop of the uneven | corrugated fabric 14, the 2nd press element (roll) 13 is located in the loop of the forming felt 8, and forms felt at the press nip N1. 8 and the textured fabric 14 come into contact. The main press 11 may be a long nip press or a shoe press (not shown).
The uneven fabric 14 has an endless loop shape and runs around a plurality of guide rolls 15 and a smooth transfer roll 16 facing the drying unit 4. The uneven fabric 14 contacts with the fibrous web 101 conveyed by the forming felt 8 through the press nip N1 of the main press 11 when traveling around the first press element (roll) 12. Then, at the press nip N <b> 1, the uneven fabric 14 performs dehydration and uneven formation of the fibrous web 101 to form the uneven fibrous web 102. The uneven fibrous web 102 is conveyed to the transfer roll 16 by the uneven fabric 14.
The transfer roll 16 faces a drying cylinder 19 of the drying unit 4 described later, and forms a transfer nip N2 therebetween. And the uneven | corrugated fibrous web 102 conveyed by the transfer nip N2 is provided only to drying, without performing press and spin-drying | dehydration.

In the press section 3 (press nip N1), the forming felt 8 functions as a water-receiving press felt 17 that is elastically deformable and compressible in the z-direction (thickness direction). The water-receiving press felt 17 immediately separates the textured fibrous web 102 that has passed through the press nip N1, and prevents the web 102 from being wetted again.
While passing through the press unit 3, the dryness of each of the

webs

101 and 102 can be in the range of fiber concentration from 15 to 30% to 42 to 52%.

The drying unit 4 includes a drying cylinder 19, a creping doctor 21, and a hood 22 that covers the drying cylinder 19. In the example of FIG. 7, the drying cylinder 19 is a Yankee dryer, but other types of drying units (for example, an air-through dryer or a metal drying belt) can be applied. Further, the drying unit may be a single drying unit (for example, one cylinder as shown in FIG. 7), or may be constituted by a plurality of drying units.
The surface of the drying cylinder 19 forms a drying surface 20 for drying the textured fibrous web 102 in the vicinity of the transfer nip N2. The creping doctor 21 is also disposed downstream of the drying surface 20 and crepes the concavo-convex fibrous web 102 dried by the drying surface 20, thereby providing a final web that has been both concavo-convex and creped. 103 is obtained. With crepe is a known method in which paper is mechanically compressed in the machine direction (machine running direction) to form a wavy crease called crepe, and the paper is bulky, soft and water-absorbing. , Imparts surface smoothness, aesthetics (crepe shape), etc.
Then, the uneven fibrous web 102 is transferred from the uneven fabric 14 to the drying surface 20 of the drying cylinder 19 at the transfer nip N2. The pressure in the transfer nip N2 is 1 MPa or less, and the web 102 does not dehydrate at this pressure.
In order to reliably transfer the web 102 from the uneven fabric 14 to the dry surface 20 side, an adhesive may be applied to the dry surface 20 by the spray device 23. The spray device 23 can be placed between the creping doctor 21 and the transfer nip N2 at a position where the drying surface 20 is open.

Examples of the uneven fabric 14 include a mesh-like wire in which metal or synthetic resin (plastic) wires are knitted in the vertical and horizontal directions as warps and wefts. As the number of the wires, the number of warps and wefts may be 20 to 70 / 2.54 cm, preferably 20 to 60 / 2.54 cm, more preferably 20 to 50 / 2.54 cm, respectively. The wire diameter of this wire may be 0.21 to 0.80 mm, preferably 0.25 to 0.80 mm, more preferably 0.30 to 0.80 mm.
When the number of warps and wefts is less than the above range, or when the diameters of the warp and wefts exceed the above range, the unevenness of the surface of the uneven fabric 14 is too strong and the unevenness of the surface of the obtained web is also strong. It becomes too much and the touch (smoothness) may be inferior.
When the number of warps and wefts exceeds the above range, or when the diameters of the warp and weft are less than the above range, the unevenness of the surface of the uneven fabric 14 is too low, and the unevenness of the surface of the obtained web is also The water absorption becomes lower than the above range.
Note that a general fabric that is not a textured fabric has warp and weft numbers of about 70 to 200 / 2.54 cm, respectively. The diameters of the warp and weft are about 0.08 to 0.20 mm.
The number of wires and the wire diameter shown above are the values of the top surface of the wire (surface on which the wet paper and the wire are in contact).

In hand towel processing, the presence or absence of calendering and embossing and the presence or absence of printing can be selected as appropriate.

The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention covers various modifications and equivalents included in the concept and scope of the present invention.

The pulp composition (mass%) is set to NBKP 50% and LBKP 50%, and the fabric press type papermaking machine 50 shown in FIG. 7 is used for two-layered and one-layered hand towels having the characteristics shown in Table 1 and Table 2, respectively. An uneven fibrous web 103 was produced.
As the concavo-convex fabric 14, a mesh-like plastic wire knitted longitudinally and laterally as warp and weft was used, and the number of warp and weft meshes and the wire diameter of the wire were defined as shown in Tables 1 and 2.

Furthermore, the final web was processed into two-layered and one-layered hand towels, and the following evaluation was performed.
WGMT (Wet Geometric Tensile Strength): Based on the former JIS S3104, the wet tensile strength WMDT and the wet transverse tensile strength WCDT were measured, and the square root of these products was calculated.
Basis weight: measured based on JIS P8124.
Thickness: Measured using a thickness gauge (a dial thickness gauge “PEACOCK” manufactured by Ozaki Seisakusho). The measurement conditions were a measurement load of 250 gf and a probe diameter of 30 mm. A sample was placed between the probe and the measurement table, and the gauge was read when the probe was lowered at a speed of 1 mm or less per second. The measurement was performed at 10 different points by stacking 10 samples, and the measurement results were averaged. Then, the average value obtained was divided by the number of sheets to obtain the paper thickness per sheet.
Specific volume: The thickness per sheet was divided by the basis weight and expressed as a volume cm ³ per unit g.
Water absorption: In accordance with the old JIS-S3104 method, 0.1 ml of purified water was dropped in one-layer product and two-layer product at a temperature of 23 ± 1 ° C and humidity of 50 ± 2%. The time taken (seconds) was measured.
Water absorption: measured as described above.
Height difference of unevenness on the front and back surfaces of the kitchen towel and the area ratio of the recesses: measured as described above.

TS7, TS750, and D were measured using the tissue softness measuring apparatus TSA. The measurement conditions are also as described above.
Evaluation of wipeability, softness, smoothness, and resistance to tearing was performed by sensory evaluation by 20 monitors. Relative evaluation was performed with an evaluation standard of 10 points. The evaluation criteria are as follows. If the evaluation is 5 points or more, the characteristics are excellent.
The sensory evaluation of the wiping property is an evaluation of whether the hand moisture is wiped off with a hand towel after washing the hand, and the moisture can be wiped cleanly. The amount of water absorption greatly affects the water absorption.
◎: 9 to 10 points ○: 7 to 8 points △: 5 to 6 points ×: 1 to 4 points Note that basis weight, tensile strength (WGMT), thickness, specific volume, and tissue softness measuring device TSA The measurement was performed after maintaining the equilibrium state under the temperature and humidity conditions (23 ± 1 ° C., 50 ± 2% RH) specified in JIS-P8111.

The results obtained are shown in Table 1 for 1 ply hand towels and in Table 2 for 2 ply hand towels.

As is clear from Tables 1 and ² , in each example where the basis weight of one set is 15 to 45 g / m ² , the water absorption in the case of 1 ply is 60 to 230 water-g / m ² , The water absorption was 2.3 to 25.0 seconds / 0.1 mL. In the case of 2 plies, the water absorption was 100 to 500 water-g / m ² and the water absorption was 0.0 to 3.0 seconds / 0.1 mL. Thus, a hand towel excellent in water absorption (water absorption and water absorption) was obtained even when the basis weight was low.
In each of the examples, a predetermined uneven fabric was pressed onto the wet paper web and the unevenness was made at the same time as the dehydration. Therefore, the height difference of the unevenness on the front and back surfaces was 100 to 600 μm, and the area of the recesses on the front and back surfaces The average rate was 2-12%.
Further, in each of the examples of one ply, in Example 5 in which the number of warps and wefts of the uneven fabric is the largest and the wire diameter is the thinnest, the surface unevenness is lower than in the other examples. The height difference of the unevenness and the area ratio of the recesses are smaller than those of the other examples, but there is no practical problem.
In the case of Example 9 where the number of warp and weft yarns of the uneven fabric is minimized and the wire diameter is the thickest, the surface unevenness is higher than other examples, the height difference of the unevenness and the area ratio of the recesses Although the value is larger than that of the other examples, there is no practical problem.
Example 14 is a product obtained by further calendaring Example 12, and the difference in height of the unevenness is lower than that of Example 12, but there is no practical problem.

On the other hand, in the case of Comparative Example 1 in which one set of basis weights was less than 15 g / m ² , the water absorption of 1 ply was less than 60 water-g / m ² , and the water absorption (wiping property) was inferior. In the case of Comparative Example 1, the strength (WGMT) also decreased and it was easily broken.
In the case of one-ply comparative example 2 in which the basis weight of one set exceeds 45 g / m ² , the water absorption amount of 1 ply exceeds 230 water-g / m ² and is excellent in water absorption, but becomes hard and soft. inferior. Similarly, in the case of Comparative Example 11 with two plies in which the basis weight of one set exceeds 45 g / m ² , the water absorption of two plies exceeds 500 water-g / m ² and is excellent in water absorption, but becomes hard. The softness was inferior.
In Table 1 (one-ply hand towel), in the case of Comparative Example 3 in which the number of warps and wefts of the uneven fabric is larger than that of the example and the wire diameter is thinner than that of the example, the surface unevenness is too low, The level difference of the unevenness and the area ratio of the recesses were less than the above ranges, and the water absorption (water absorption and water absorption) and the wiping property were inferior.
In the case of Comparative Example 4 in which the number of warps and wefts of the uneven fabric is less than that of the example and the wire diameter is thicker than that of the example, the unevenness of the surface becomes too high, the level difference of the unevenness and the value of the area ratio of the recess However, the smoothness was inferior.
In the case of Comparative Examples 5 and 6 which are commercially available 1-ply hand towels, the unevenness of the surface becomes too low, the height difference of the unevenness is less than the above range, the bulk is reduced, and the water absorption is 25.0 seconds / 0. More than 1 mL, softness and smoothness were inferior. This is because in the case of Comparative Examples 5 and 6, the paper was made without using the uneven fabric 14 described above. In addition, although the unevenness | corrugation of the comparative example 6 is low, it is thought that the reason for being inferior in smoothness is having performed the embossing process mechanically in the process after papermaking. In the case of Comparative Examples 5 and 6, the specific volume was lower than that of the Example, so it became hard (D value was less than 2.0 mm / N) and the softness was inferior.
In the case of Comparative Example 11 in which one set of basis weight exceeded 45 g / m ² , it became hard (D value was less than 2.0 mm / N), and the softness was inferior.
In the case of Comparative Example 12, which is a commercially available two-ply hand towel, the basis weight of one set exceeds 45 g / m ² , becomes hard (D value is less than 2.0 mm / N), and the softness is inferior. . This is because, in the case of Comparative Example 12, paper was made without using the uneven fabric 14 described above. Moreover, in the case of the comparative example 12, the level difference of the unevenness | corrugation of the surface became less than the said range. Since Comparative Example 11 had a higher basis weight than the two-ply example, the softness was inferior and the smoothness was slightly inferior.
The WGMT (strength) can be appropriately adjusted depending on, for example, the raw material of the pulp and its blending amount, the beating degree, the presence / absence of addition of a paper strength agent, and papermaking conditions.

14 Concavity and convexity fabric 101 Fibrous web

Claims

It consists of a set of pulp as a main component and one or more sheets stacked, and the basis weight of the one set is 15 to 45 g / m 2 ,
When the one set is composed of one sheet, the water absorption is 60 to 230 water-g / m 2 , and when the one set is composed of two or more sheets, the water absorption is 100 to 500 water- g / m 2 ,
And the water absorption specified in the old JIS-S3104 method is 25.0 seconds / 0.1 mL or less when the one set consists of one sheet, and the one set consists of two or more sheets Hand towel that is 3.0 seconds / 0.1 mL or less.
The hand towel according to claim 1, wherein the unevenness of the surface unevenness is 100 to 600 µm.
The hand towel according to claim 1 or 2, wherein the area ratio of the recesses on the surface is 2 to 12%.
When the tissue softness measuring device TSA is pressed into the sample of the hand towel placed on the sample table from above with a pressing force of 100 mN and 600 mN without rotating the bladed rotor,
The measured value of rigidity (D), expressed by the amount of deformation in the vertical direction of the sample at an indentation pressure of 100 mN and 600 mN, respectively, is 2.0 to 3.2 mm / N. The hand towel described in crab.
Using the tissue softness measuring device TSA, the bladed rotor was pushed in from the top as a pushing pressure of 100 mN on the sample of the hand towel placed on the sample table, and then rotated at a rotation speed of 2.0 (/ sec). When measuring vibration with a vibration sensor,
The intensity of the maximum peak (TS750) of the first spectrum from the low frequency side automatically acquired by software on the TSA is 16 to 50 dBV 2 rms, and the intensity of the maximum peak (TS7) of the spectrum including 6500 Hz is The hand towel according to any one of claims 1 to 4, which is 19 to 40 dBV 2 rms.
The hand towel according to any one of claims 1 to 5, wherein the specific volume is 4.5 to 9.0 cm 3 / g.
It is the square root of the product of the tensile strength WMDT in the longitudinal direction when wet according to the former JIS S3104 and the tensile strength WCDT in the lateral direction when wet of the hand towel (WMDT × WCDT) 1/2 (WGMT) The hand towel according to any one of claims 1 to 6, wherein is 2.0 to 6.0 N / 25 mm.
The method for producing a hand towel according to any one of claims 1 to 7, wherein the web is dried after pressing the uneven fabric on the wet paper web to perform unevenness simultaneously with dehydration. .