JP2014073420A - Toilet paper product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toilet paper product which satisfies three properties of strength, bulk (specific volume) and softness, and to provide a method of producing the same.SOLUTION: There is provided a toilet paper product which mainly consists of pulp and is formed of one sheet or one set of two- or more-ply sheets, and in which a basis weight of one sheet is 10-25 g/m, a specific volume is 7-15 cm/g, (DMDT×DCDT)(DGMT) is 1.4-3.8 N/25 mm that is a square root of a product of DMDT (dry machine direction tensile strength) and DCDT (dry cross direction tensile strength) based on JIS P8113, and a height difference in a surface unevenness is 80-250 μm.

Description

  The present invention relates to a toilet paper product mainly composed of pulp and a method for producing the toilet paper product.

Rolled or sheet-like toilet paper products are manufactured by appropriately cutting a toilet paper web in which one or two or more toilet paper base papers are stacked into a predetermined size.
In a toilet paper product (web), a high bulk (specific volume) is an important factor in terms of quality in order to ensure moisture absorption capability. In addition, strength and softness (a total sensation of suppleness, smoothness, and volume) are also important.

As a method of obtaining a high-bulk and soft paper product, a chemical called debonder or bulking agent is added to the papermaking raw material in the papermaking process and chemically treated to suppress loosening of the fiber layer of the web by suppressing interfiber bonding of pulp fibers. A method of giving is known (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 processing on the wet paper web between the formation of the wet paper 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 above-mentioned chemical treatment method, there is a problem that the cost of the medicine is high and the strength of the web is lowered because the fiber-to-fiber bond of the pulp is lowered. Furthermore, the paper strength reduction due to the chemical treatment is compensated for by blending raw materials, changing the beating conditions, and adding a temporary wet paper strength agent. Although 3) is disclosed, there is a problem in that the water absorption rate decreases due to the use or beating of the drug. 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 by applying to this Yankee dryer. And even if it tries to suppress the bulk fall by creping by adding the above-mentioned bulking agent to a pulp raw material, only the bulkiness effect of about 3 to 5% is obtained at most, On the other hand, intensity | strength falls remarkably.
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 for 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 4). 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 5). 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.

In addition, when toilet paper is made using normal fabric without using the fabric press method, when the bulk (specific volume) is increased, either strength or hand feel is lowered. For example, a technique in which the specific volume is increased to about 9 cm ³ / g (density 0.11 g / cm 3) has been disclosed (Patent Document 6). ) Is inferior (see Comparative Examples 6, 12, and 13 of commercially available products in Tables 1 and 2 below).

Japanese Unexamined Patent Publication No. Hei 7-189171 JP-A-8-3890 JP 2004-209150 A JP-A-6-158578 Special table 2001-521999 gazette JP 2005-204868

However, even if the technique described in Patent Document 5 is used, it cannot be said that it is sufficient to satisfy all of the strength, bulk (specific volume), and softness of the toilet paper web and the toilet paper product.
Accordingly, an object of the present invention is to provide a toilet paper product satisfying three of strength, bulk (specific volume), and softness, and a method for producing the toilet paper product.

In order to solve the above-mentioned problems, the toilet paper product of the present invention is made of a paper material mainly composed of pulp, is subjected to calendering, and consists of a set of one sheet or two or more sheets, The basis weight of one sheet is 10 to 25 g / m ² , the specific volume is 7 to 15 cm ³ / g, and the longitudinal tensile strength DMDT of the toilet paper product when dried based on JIS P8113 The square root of the product of the tensile strength DCDT in the transverse direction when dried (DMDT × DCDT) ^1/2 (DGMT) is 1.4 to 3.8 N / 25 mm, and the field of view is 1.0-1.4 mm. The height difference of the unevenness of the surface is 80 to 250 μm, and the area ratio of the recesses on the surface performed under the condition of the scanning area of 4 cm × 4 cm is 5 to 15%.

The water absorption specified in the old JIS-S3104 method is 3.0 seconds / 0.01 mL or less when the one set consists of one sheet, and the one set consists of two or more sheets. It is 3.0 seconds / 0.1 mL or less, and the ease of loosening by JIS P4501 method is preferably 5 to 40 seconds.
It is preferable to perform calendar processing with a pair of rolls having a gap of 20 to 80% with respect to the paper thickness after drying and papermaking.

The method for producing a toilet paper product according to the present invention is a method for producing the toilet paper product, in which calendering is performed with a pair of rolls having a gap of 20 to 80% with respect to papermaking and a web thickness after drying.
The web thickness after the papermaking and drying and before the calendering is preferably 130 μm or more and 350 μm or less.

The method for producing a toilet paper product according to the present invention is a method for producing the toilet paper product, in which an uneven fabric is pressed against a wet paper web to perform unevenness simultaneously with dehydration, and then the web is dried.
It is preferable that the uneven fabric is made of a mesh-like wire in which metal or synthetic resin wires are knitted vertically and horizontally as warps and wefts.

  According to the present invention, a toilet paper product having improved strength, bulk (specific volume) and softness can be obtained.

It is a figure which shows an example of the manufacturing apparatus of the web of the toilet paper product which concerns on embodiment of this invention. It is a figure which shows the structure of the calendar part at the time of manufacturing the web of the toilet paper product which concerns on embodiment of this invention. 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 which crosses the observation visual field of an image. It is a figure which shows the image which took in the toilet paper surface with the image scanner.

Embodiments of the present invention will be described below.
The toilet paper product according to the embodiment of the present invention is composed of one sheet or a set of two or more sheets, and the basis weight of one sheet is 10 to 25 g / m ² and the specific volume is 7 to 15 cm ³ /. g, the DGMT of the toilet paper product is 1.4 to 3.8 N / 25 mm, and the height difference of the surface irregularities is 80 to 250 μm. The area ratio of the recesses on the surface of the toilet paper product is preferably 5 to 15%.

When the basis weight of one sheet is less than 10 g / m ² , the strength decreases, and when it exceeds 25 g / m ² , the cost increases and the softness is inferior. The basis weight is preferably 10 to 22 g / m ² , more preferably 13 to 19 g / m ² .
When the specific volume (per set) of the toilet paper product is less than 7 cm ³ / g, the soft feeling is poor and the softness (texture) is inferior. On the other hand, when the specific volume exceeds 15 cm ³ / g, the bulk (bulkiness) becomes high, but the smoothness is inferior and the smoothness (tactile feel) is deteriorated. The specific volume is preferably 7~12cm ³ / g, more preferably 7.5~10.5cm ³ / g.

Further, if the DGMT of the toilet paper product is less than 1.4 N / 25 mm, the toilet paper product is easily shaken and is not suitable for practical use. When DGMT exceeds 3.8 N / 25 mm, it becomes hard and the softness is impaired. The DGMT is preferably 1.4 to 3.4 N / 25 mm, more preferably 1.4 to 3.0 N / 25 mm.
Note that DGMT is the square root of the product of the tensile strength DMDT (Dry Machine Direction Tensile strength) in the dry direction and the tensile strength DCDT (Dry Cross Direction Tensile strength) in the horizontal direction during the drying based on JIS P8113. It is expressed by (DMDT × DCDT) ^1/2 (DGMT: Geometric Tensile Strength).
As an example of a method for managing the specific volume and DGMT within the above ranges, it is possible to set the basis weight to the above range, and press the uneven fabric to be described later against the wet paper web and perform unevenness simultaneously with dehydration.

Toilet paper contains pulp as a main component (50% by mass or more). Pulp includes wood pulp, waste paper pulp, and non-wood pulp, but the pulp constituting toilet paper may be composed of 100% wood pulp, and may include waste paper pulp and non-wood pulp. Examples of components other than pulp include fillers, synthetic fibers, and natural fibers. In order to obtain the target quality, it is preferable to use wood pulp of NBKP: LBKP = 10: 90 to 70:30 (mass ratio) as a raw material, and a more preferable range is NBKP: LBKP = 20: 80 to 70: 30 and a more preferable range is NBKP: LBKP = 20: 80 to 40:60. Pulp produced from Eucalyptus eucalyptus represented by Eucalyptus genus Grandis and Eucalyptus globulus is preferred as the grade of LBKP. Or waste paper pulp can be contained to about 50 mass% with respect to the wood pulp of this pulp ratio. 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 20% by mass or less with respect to the wood pulp.
In addition, in order to ensure an appropriate strength for the toilet paper, raw materials can be blended by ordinary means, and the strength can be adjusted by beating the pulp fibers. As the beating for obtaining the target quality, 0 to 200 ml, more preferably 50 to 200 ml, and still more preferably 50 to 150 ml filtered water with respect to a commercially available virgin pulp in Canadian standard freeness measured by JIS P8121. Reduce the degree. Moreover, you may use a wet paper strength enhancer suitably.

The height difference of the unevenness on the surface of the toilet paper product is 80 to 250 μm, preferably 90 to 220 μm, more preferably 100 to 220 μm. Further, the area ratio of the concave portions on the surface is preferably 5 to 15%, more preferably 7 to 15%, and further preferably 7 to 13%.
In addition, the surface means both sides facing the outside of the product (that is, the opposite side of the sheet overlapping surface) if the toilet paper 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 by a process other than the paper machine (for example, a roll winder).

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. 3 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. 3 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. 4 is a (measurement) cross-sectional curve S representing the unevenness of the actual sample surface, but noise (fiber lumps on the surface of the toilet paper or fibers extending like a beard) 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.
4 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 the above-mentioned 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 toilet paper, considering dark portions below a predetermined threshold as recesses, and calculating the area ratio.
Specifically, the surface of the toilet paper is captured as image data as shown in FIG. 5 using a commercially available image scanner (for example, GT-X770 manufactured by Epson), and a predetermined image analysis device (for example, manufactured by Nippon Paper Unitech Co., Ltd.). (Easy Scan))), the area ratio of the dark portion below a predetermined threshold value is obtained under the conditions of a resolution of 800 dpi and a scan area of 4 cm × 4 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. Thereafter, for the particles having a particle size of 200 to 799 μm, the area of each particle was integrated and converted into the area ratio of the dark part (recess) per 1 m ^{2 of} the image area (for example, particles having a measurement area of 0.0016 m ^{2 and} 200-799 μm) If the integrated area is 200mm2, the area ratio (%) is 200mm2 ÷ 0.0016m2 x 100 = 12.5%).
In measuring the area ratio, the toilet paper sample is placed along one side of the toilet paper so that no wrinkles, perforations, folds, or the like enter the sample, and image data is captured. Next, one side of the toilet paper is rotated by 90 ° C. with respect to the scanner, and each image data is captured (a total of four image data). 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 toilet paper 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.
In addition, if the 4cm x 4cm scan area (0.0016m2) cannot be secured due to the perforation or crease in the toilet paper 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 0.0016m2. For example, if two places of 2 cm × 4 cm (0.0008 m 2) are measured, the measurement area becomes 0.0016 m 2.

When the height difference of the unevenness and the area ratio of the recesses are within the above ranges, the toilet paper becomes appropriately bulky, and the softness (paper texture) is improved while ensuring the strength. In addition, water absorption is also improved.
On the other hand, if the height difference of the unevenness and the area ratio of the recesses are less than the above ranges, the unevenness of the surface of the toilet paper becomes too low, and the softness (paper texture) is inferior.
If the height difference of the unevenness and the area ratio of the recesses exceed the above range, the unevenness on the surface of the toilet paper becomes too high, the strength (DGMT) is reduced to less than 1.4 N / 25 mm, and it is easy to break and smoothness is reduced. 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.
In general, toilet paper is often mechanically embossed after paper making in a process other than the paper machine (for example, a roll winder). When embossing is performed, the bulk is increased and the softness is improved, but the strength is likely to decrease, so it is difficult to achieve both softness and strength.

When the water absorption specified in the old JIS-S3104 method of toilet paper products is composed of one sheet (one ply), it is preferably 1.0 to 3.0 seconds / 0.01 mL, More preferably, it is 1.0 to 2.0 seconds / 0.01 mL. When one set is composed of two or more sheets (two or more plies), the water absorption is preferably 1.0 to 3.0 seconds / 0.1 mL, and 1.0 to 2.0 seconds / 0. More preferably, it is 1 mL.
The smaller the water absorption, the better. However, since it is not possible to measure the water absorption of 1.0 second or less, the water absorption of 1.0 second or less is “1.0 second (in the following table,“ ≦ 1.0 ”). Therefore, the lower limit of water absorption is 1.0 second / 0.01 mL for 1 ply and 1.0 second / 0.1 mL for 2 plies or more. Become.
On the other hand, if the water absorption exceeds 3.0 seconds / 0.01 mL in the case of 1 ply, or exceeds 3.0 seconds / 0.1 mL in the case of 2 plies or more, the water absorption is slow and may not be practical. is there. In addition, a water absorption is prescribed | regulated by old JIS-S3104 method, and "0.1 mL (or 0.01 mL)" is the dripping amount of the water to a toilet paper product.

The ease of loosening of toilet paper products according to the JIS P4501 method is preferably 5 to 40 seconds, more preferably 5 to 35 seconds, and still more preferably 5 to 30 seconds.
If the ease of unraveling is less than the above range, it will be unraveled as soon as moisture adheres, and if the ease of unraveling exceeds the above range, it will be difficult to unravel.

  The toilet paper of the present invention is formed by stacking the above-mentioned sheets one by one, or by stacking two or more sheets. This toilet paper can be formed into, for example, a roll shape that is slit to the product width, or a sheet shape that is cut into a product width and a length, respectively, and then folded in a C shape.

Next, the manufacturing method of the web which comprises the sheet | seat of the toilet paper which concerns on embodiment of this invention is demonstrated using FIG. 1, FIG. FIG. 1 shows an example of a web manufacturing apparatus 50.
The apparatus 50 shown in FIG. 1 is a fabric press type paper machine, and can produce the web 103 with unevenness only by pressing means without using a ventilation drying (TAD) facility 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. 1, the main press 11 is a roll press and forms a twin roll in which the first and second pressing elements 12 and 13 face each other. The first press element (roll) 12 is located in the loop of the textured fabric 14, the second press element (roll) 13 is located in the forming felt 8 loop, and the forming felt 8 is formed at the press nip N1. And the uneven fabric 14 come into contact with each other. 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. And in the press nip N1, the uneven | corrugated fabric 14 dehydrates and uneven | corrugates the fibrous web 101, and forms the uneven | corrugated fibrous web 102. FIG. 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 section 3, the dryness of each of the webs 101, 102 can be in the range of fiber concentration 15-30% to 42-52%.

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. 1, 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. 1), 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 65 / 2.54 cm, and more preferably 25 to 60 / 2.54 cm. The wire diameter of the wire may be 0.21 to 0.70 mm, preferably 0.21 to 0.55 mm, and more preferably 0.21 to 0.45 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 toilet paper is also strong. The height difference of the unevenness and the area ratio of the recessed portion exceed the above range, the unevenness of the surface of the toilet paper becomes too high, the strength (DGMT) is lowered to less than 1.4 N / 25 mm, it is easily broken, and the smoothness is 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 on the surface of the uneven fabric 14 is too low, and the unevenness on the surface of the toilet paper is also low. The height difference of the unevenness and the area ratio of the recesses are less than the above range, and the softness (paper texture) is inferior.
As a general fabric, the number of warps and wefts is about 70 to 200 / 2.54 cm, respectively. The diameters of the warp and the 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).

Next, with reference to FIG. 2, an example of calendar processing in the method for manufacturing a toilet paper web according to the embodiment of the present invention will be described.
The calender part 60 is composed of a pair of opposed rolls 61 and 62, and the paper 103 and the web 103 with the unevenness after drying are inserted into the gap between the rolls 61 and 62 and calendered.
Here, by setting the gap distance t ₁ between the rolls 61 and 62 to 20 to 80% with respect to the thickness t ₀ of the web 103, a smoother and more flexible bulky web can be obtained.
When the distance t ₁ is less than 20% of the thickness t ₀ , the web becomes smooth, but valcross is generated, and a bulky and fluffy web with a specific volume of 7 to 15 cm ³ / g may not be obtained. If the distance t ₁ exceeds 80% of the thickness t ₀ , it may be difficult to smooth the web.
If the distance t ₁ is 20 to 80% of the thickness t ₀ , the caliper (thickness) of the web that has passed the rolls 61 and 62 is restored to some extent naturally, minimizing caliper reduction, flexibility, The surface property can be improved while minimizing the thickness reduction.
As the rolls 61 and 62, a steel roll, a chilled roll, a metallic roll such as a surface hard plating finish roll, or a cylinder coated with an elastic material can be used. A metal roll is preferable in that the web can be made smoother.
The web thickness t ₀ before calendering is 130 to 350 μm / sheet, preferably 150 to 350 μm / sheet, more preferably 200 to 300 μm / sheet. The web thickness after calendering is 80 to 280 μm / sheet, preferably 100 to 250 μm / sheet, more preferably 100 to 200 μm / sheet.
Furthermore, the thickness after processing the toilet paper product is 0.8 to 2.5 mm / 10 sheets, preferably 0.8 to 2.0 mm / 10 sheets, more preferably 0.85 to 2.0 mm / 10 sheets. .

  In toilet paper processing, the presence or absence of calendar processing, embossing, and the presence or absence of printing can be selected as appropriate.

  It goes without saying that the present invention is not limited to the above-described embodiments, and extends to various modifications and equivalents included in the spirit and scope of the present invention.

  A paper press of the fabric press system shown in FIG. 1 is used as a web of toilet paper of one and two sheets of sheets having the characteristics shown in Tables 1 and 2 with NBKP 30% and LBKP 70%. 50 was used to produce a web 103 with unevenness. Next, using the pull unit calender part 60 shown in FIG. 2, the paper 103 and the web 103 after drying were calendered. Table 1 shows the calendering conditions. As the concavo-convex fabric 14, a mesh-like plastic wire knitted longitudinally and laterally as warp and weft was used, and the warp and weft numbers and wire diameters of the wire were defined as shown in Tables 1 and 2.

Furthermore, the final web after the calendar processing was processed into toilet paper products of one and two layers, and the following evaluation was performed.
Basis weight: measured based on JIS P8124 and converted per sheet.
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. One measurement was performed by stacking 10 samples, and the measurement was repeated 10 times and the measurement results were averaged.
Specific volume: The thickness per sheet was divided by the basis weight per sheet, and expressed as a volume cm ³ per unit g.
DGMT (Geometric Tensile Strength): The square root of the product of the longitudinal tensile strength DMDT during drying and the lateral tensile strength DCDT during drying measured according to JIS P8113 was calculated.
Water absorption: 0.01 ml (in the case of 1 ply) or 0.1 ml (in the case of 2 plies) is dropped in accordance with the old JIS-S3104 method at a temperature of 23 ± 1 ° C and a humidity of 50 ± 2%. Then, the time (seconds) for the water droplets to be absorbed by the toilet paper product was measured.
The height difference of the unevenness on the front and back surfaces of the toilet paper and the area ratio of the recesses were measured as described above.
Unraveling ease: in accordance with JIS P4501.
The basis weight, DGMT, thickness, and ease of loosening were measured after maintaining the equilibrium state under the temperature and humidity conditions specified in JIS-P8111 (23 ± 1 ° C., 50 ± 2% RH).

Evaluation of softness, smoothness, and resistance to tearing was performed by sensory evaluation by 20 monitors. The evaluation criteria was a relative evaluation of each sample with a maximum score of 5 points. The evaluation criteria are as follows. If the evaluation is 3 points or more, the characteristics are excellent. In addition, 1ply was 1 to 4 points, and 2ply was 1 to 5 points.
○: 5 to 3 points ×: 2 to 1 points

  The obtained results are shown in Table 1 for the one-layer toilet paper and shown in Table 2 for the two-layer toilet paper.

As apparent from Tables 1 and 2, the basis weight of one sheet is 10 to 25 g / m ² , the specific volume is 7 to 15 cm ³ / g, and the strength (DGMT) of the toilet paper product is 1.4. In the case of each example of ˜3.8 N / 25 mm, a toilet paper product excellent in strength, bulk (specific volume), and softness was obtained.
In the case of each example, since a predetermined uneven fabric was pressed on the wet paper web and the unevenness was made at the same time as dehydration, the height difference of the unevenness on the front and back surfaces was 80 to 250 μm, and the area of the recesses on the front and back surfaces The rate was 5-15%.
In the case of Example 4 in which the number of warp and weft yarns of the uneven fabric is maximized and the wire diameter is the thinnest, the unevenness of the toilet paper surface is lower than that of the other examples, the unevenness level difference and the recesses Although the value of the area ratio is smaller than that of the other examples, there is no practical problem.
In Examples 7 and 8 in which the number of warp and weft yarns of the uneven fabric is minimized and the wire diameter is the thickest, the unevenness of the toilet paper surface is higher than in the other examples, the unevenness level difference and the recesses Although the value of the area ratio is larger than that of the other examples, there is no practical problem.

On the other hand, in the case of Comparative Example 1 in which the basis weight of one sheet was less than 10 g / m ² , the strength (DGMT) decreased to less than 1.4 N / 25 mm, and was easily broken. In the case of Comparative Example 1, the water absorption exceeded 3.0 seconds / 0.01 mL, which was not suitable for practical use.
In the case of Comparative Example 11 in which the basis weight of one sheet exceeded 25 g / m ² , the strength (DGMT) became too high exceeding 3.8 N / 25 mm, and the softness was inferior.
In the case of Comparative Example 2 in which calendering was performed with a pair of rolls having a gap of less than 20% with respect to the paper thickness after papermaking and drying, the calendering was excessively crushed and the specific volume was 7 cm ³ / g. The difference in height between the front and rear surface irregularities was less than 80 μm, and the softness was inferior.
In the case of Comparative Example 3 in which the papermaking and the web after drying were calendered with a pair of rolls having a gap exceeding 80%, the specific volume exceeded 15 cm ³ / g and became too bulky, resulting in poor smoothness.
In the case of Comparative Example 4 in which the number of warps and wefts of the uneven fabric is increased from that of the example and the wire diameter is made thinner than that of the example, the unevenness of the toilet paper surface becomes too low, and the level difference of the unevenness is in the above range. The softness was inferior.
In the case of Comparative Example 5 in which the number of warp and weft yarns 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 toilet paper surface becomes too high, The area ratio exceeded the above range, the strength (DGMT) decreased to less than 1.4 N / 25 mm, and it was easily broken, and the smoothness was inferior.
In the case of Comparative Examples 6, 12, and 13, which are commercially available toilet papers, the unevenness of the surface unevenness was less than 80 μm, and the softness was inferior. The DGMT (strength) can be appropriately adjusted depending on, for example, the raw material of pulp and the blending amount thereof, the beating degree, the presence / absence of addition of a paper strength agent, and papermaking conditions.

14 Concavity and convexity fabric 101 Fiber web

The present invention relates to toilet paper products composed mainly of pulp.

However, even if the technique described in Patent Document 5 is used, it cannot be said that it is sufficient to satisfy all of the strength, bulk (specific volume), and softness of the toilet paper web and the toilet paper product.
Accordingly, an object of the present invention is to provide a toilet paper product satisfying three of strength, bulk (specific volume), and softness.

In order to solve the above-mentioned problems, the toilet paper product of the present invention is made by making a paper material mainly composed of pulp, and the web thickness before paper making and drying and before calendering is 130 μm or more and 350 μm or less, It is calendered and consists of a set of one sheet or two or more sheets, the basis weight of one sheet is 10 to 25 g / m ² , the specific volume is 7 to 15 cm ³ / g, (DMDT × DCDT) ^1/2 (DGMT) is the square root of the product of the tensile strength DMDT in the longitudinal direction when dried according to JIS P8113 and the tensile strength DCDT in the transverse direction when dried of the toilet paper product. 1.4 to 3.8 N / 25 mm, the difference in height of the surface irregularities when measured with a field of view of 1.0 to 1.4 mm is 80 to 250 μm, and the surface recesses made under the conditions of a scanning area of 4 cm × 4 cm. surface The rate is 5-15%.

The water absorption specified in the old JIS-S3104 method is 3.0 seconds / 0.01 mL or less when the one set consists of one sheet, and the one set consists of two or more sheets. It is 3.0 seconds / 0.1 mL or less, and the ease of loosening by JIS P4501 method is preferably 5 to 40 seconds.
To Extract granulation and web thickness after drying is preferably made by performing the calendering at a pair of rolls having a gap of 20-80%.

Claims (7)

A paper material mainly composed of pulp is made, calendered, and composed of a set of one sheet or two or more sheets, and the basis weight of one sheet is 10 to 25 g / m ^2. A toilet paper product having a specific volume of 7 to 15 cm ³ / g,
(DMDT × DCDT) ^1/2 (DGMT) is the square root of the product of the tensile strength DMDT in the longitudinal direction when dried according to JIS P8113 and the tensile strength DCDT in the transverse direction when dried of the toilet paper product. 1.4 to 3.8 N / 25 mm,
Toilet paper products with a surface irregularity of 80-250 μm when measured with a field of view of 1.0-1.4 mm and an area ratio of recesses of the surface of 5-15% performed under conditions of a scanning area of 4 cm × 4 cm . The water absorption specified in the old JIS-S3104 method is 3.0 seconds / 0.01 mL or less when the one set consists of one sheet, and the one set consists of two or more sheets. 3.0 seconds / 0.1 mL or less,
The toilet paper product according to claim 1, wherein the ease of loosening according to JIS P4501 method is 5 to 40 seconds. The toilet paper product according to claim 1 or 2, wherein the toilet paper product is formed by calendering with a pair of rolls having a gap of 20 to 80% with respect to paper thickness and web thickness after drying. It is a manufacturing method of the toilet paper product in any one of Claims 1-3, Comprising: Toilet paper which performs a calendar process with a pair of roll which has a gap of 20 to 80% with respect to the paper thickness after papermaking and drying Product manufacturing method. The method for producing a toilet paper product according to claim 4, wherein the paper thickness after drying and before the calendering is 130 µm or more and 350 µm or less. It is a manufacturing method of the toilet paper product in any one of Claims 1-3, Comprising: The toilet paper product which dries a web after pressing an uneven | corrugated fabric to a wet paper web and performing unevenness | corrugation simultaneously with dehydration. Production method. The method for manufacturing a toilet paper product according to claim 6, wherein the uneven fabric is made of a mesh-like wire knitted in the vertical and horizontal directions using metal or synthetic resin wires as warps and wefts.