JP7129762B2 - toilet roll - Google Patents

Description

The present invention relates to a toilet roll wound with one-ply toilet paper.

Toilet paper is commercially available mainly in units of 4 rolls, 12 rolls, or the like. Since these packages are bulky, the amount that can be carried at the time of purchase is limited, and the amount that can be purchased at one time is naturally limited. Storage space is also limited in homes, workplaces, public facilities, and the like.
For this reason, a (long) toilet roll has been developed in which the basis weight per sheet of toilet paper is reduced to 14 g/m ² or less and the roll length is increased (Patent Documents 1 and 2). .
In addition, the applicant of the present application has developed a toilet roll in which the basis weight per sheet of toilet paper is higher than 13 g/m ² and the winding length is increased while improving the texture and feeling of use (Patent Documents 3 and 4). ).

Japanese Patent Application Laid-Open No. 2006-087703 JP 2013-208297 A JP 2014-188342 A JP 2014-233363 A

By the way, in general, toilet rolls are produced by winding a log with a product length and a width of several meters, then cutting the log into round slices in the product width in the axial direction with a log saw, and making a number of toilet rolls from one log. manufacturing.
On the other hand, in order to make a long toilet roll with a limited winding diameter, it should be tightly wound, but if it is wound too tightly, the core will be crushed when cut with a log saw. In addition, when the toilet paper sheet is not embossed, there are no gaps between the sheets, so the roll becomes tighter and the tactile sensation is inferior. Of course, if the toilet roll is wound softly, the core will not be crushed even if it is cut with a log saw, but the diameter of the roll will increase, making it difficult to attach it to the paper holder.

On the other hand, if the log is wound to the product width, cutting with a log saw is not necessary, and the problem of crushing of the core is solved.
In addition, if the diameter of the core is increased, it becomes difficult for the sheet to slack at the beginning of the sheet winding (at the point where it is wound around the core) during log production, so it is possible to increase the processing speed and improve productivity. easily crushed.

On the other hand, if a toilet roll without a core is used, the core will not be crushed, but the amount of glue used at the beginning of the sheet tends to be uneven, and when the roll is used to the end, the last part (start of winding) part) is hard and does not unravel, making it difficult to unwind, and the roll is crushed when cut with a log saw. Also, if the diameter of the core is made small, it becomes difficult to attach it to the toilet holder.
Further, increasing the mass of the core (increasing the basis weight of the core) makes the core less likely to be crushed, but the core becomes harder, leading to a decrease in core productivity and an increase in cost.
As described above, when manufacturing a long toilet roll having a core, it has been difficult to make the core less likely to collapse without impairing cost and productivity.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a long toilet roll that has a good feel to the touch and that has a core that is less likely to be crushed without impairing cost and productivity.

The present inventors have found that the roll density is important as a factor for making the core less crushable when producing toilet rolls. In other words, if the roll density is too high, the core will be tightly wound (high mass per volume) and the core will be easily crushed. It becomes difficult to fit in.
In addition, by specifying the apparent basis weight of the core, the productivity of the toilet roll is improved while suppressing the decrease in productivity and the increase in cost of the core and preventing the crushing of the core.

In order to solve the above-mentioned problems, the toilet roll of the present invention is a toilet roll obtained by winding one-ply toilet paper in a roll shape, which has a plurality of unevennesses in which one surface is a convex portion and the corresponding opposite surface is a concave portion. , the roll length is 105 to 210 m, the roll diameter is 100 to 142 mm, the apparent basis weight of the core is 220 to 570 g/m ² , the roll density is 0.17 to 0.38 g/cm ³ , and the above per 114 mm roll width The mass of the core is 3.5 to 6.4 g, the core is placed horizontally on a hard table so that the axis is horizontal, and a compressor (area 2.0 cm ² ) is placed in the center of the outer surface of the core, and the speed is 10 mm. / min, the pushing depth when the pressure applied by the compressor is 0.5 gf/cm ^{2 is T0, the pushing depth when the pressure is 250 gf/cm 2 is} Tm, and (Tm- T0) is the hardness of the core, and the hardness of the core is 0.4 to 6.9 mm (excluding 0.6 to 4.8 mm).

It is preferable that the depth of the concave portion of the unevenness is 0.01 to 0.42 mm .
The ratio represented by (hardness of the core)/(roll density) is preferably 1.4 to 23.0 mm/(g/cm ³ ).
The dry longitudinal tensile strength DMDT of the toilet paper according to JIS P8113 is preferably 2.5 to 7.5 N/25 mm.
The dry transverse tensile strength DCDT of the toilet paper according to JIS P8113 is preferably 0.7 to 2.3 N/25 mm.
The unevenness is preferably embossed.

ADVANTAGE OF THE INVENTION According to this invention, it is possible to obtain a long toilet roll that has a good tactile feel and a core that is hard to be crushed without impairing cost and productivity.

It is a perspective view showing the appearance of the toilet roll concerning the embodiment of the present invention. It is sectional drawing which shows the embossing provided in the roll surface and the back surface. It is a figure which shows an example of a roll winding machine. It is a figure which shows the measuring method of embossing depth. It is another figure which shows the measuring method of embossing depth. FIG. 6 is a diagram following FIG. 5 ; It is a figure which shows an example of a machine winder. FIG. 11 shows the measurement of embossing depth when the embossing continues in the machine direction (MD direction);

Preferred embodiments of the invention are described below, which are given for the purpose of illustration and are not intended to limit the invention.
As shown in FIG. 1, the toilet roll 10 according to the embodiment of the present invention is a toilet roll obtained by winding one-ply toilet paper 10x having a plurality of unevennesses around a core 5, and the roll length ( Winding length) is 105 to 210 m, and winding diameter DR is 100 to 142 mm.
The roll outer surface of the toilet paper 10x is referred to as a roll surface (or toilet paper surface) 10a, and the roll inner surface is referred to as a roll back surface (or toilet paper back surface) 10b.

If the roll length of the toilet roll 10 is less than 105 m, the roll length per roll becomes short, and space saving during storage cannot be achieved. If the roll length exceeds 210 m, the roll diameter DR becomes too large to fit in a toilet paper holder or the like.
The winding length is preferably 130-190 mm, more preferably 145-170 mm.

When the winding diameter DR is less than 100 mm, the winding length is also shortened to less than 105 m. When the winding diameter DR exceeds 142 mm, it becomes difficult to fit in a toilet paper holder or the like.
The winding diameter DR is preferably 112-135 mm, more preferably 117-125 mm.

The core has an apparent basis weight of 220-570 g/m ² .
If the apparent basis weight of the core is less than 220 g/m ² , the core will collapse when the toilet roll is manufactured. On the other hand, if the apparent mass of the core exceeds 570 g/m ² , the strength of the core becomes unnecessarily high, leading to an increase in core cost and poor core productivity.
The apparent basis weight of the core is expressed by (mass of core)÷(outer surface area of core). The mass and outer surface area of the core are the mass and outer surface area of the core converted per roll width of 114 mm. For example, when the mass of the core per roll width of 114 mm is 4.7 g and the outer diameter of the core is 39 mm, the apparent basis weight of the core = 4.7 g ÷ {(3.14 × 39 mm / 1000) × (114 mm / 1000 )}=337 g/m ² . Here, the core is usually made by bonding two sheets of core base paper together with an adhesive or the like. Since it is different from the rolled one, the "apparent" basis weight was used.
The apparent basis weight of the core is preferably 250-470 g/m ² , more preferably 300-370 g/m ² .

The roll weight not including the core (winding core) 5 per roll width W of 114 mm is preferably 190 to 450 g. Here, when the roll width W is different from 114 mm, W is converted to 114 mm to obtain the roll mass. For example, when the roll width W is 105 mm, the mass obtained by multiplying the roll mass by a coefficient (114/105) is the roll mass per 114 mm of W.
When the roll mass is less than 190 g, the winding length per roll becomes short, and the roll replacement frequency increases. When the roll mass exceeds 450 g, the roll diameter becomes large and it becomes difficult to fit in the toilet paper holder.
The roll mass is more preferably 240 to 400 g, more preferably 260 to 350 g.

It is preferable that the mass of the core 5 per roll width W of 114 mm is 2.8 to 7.9 g. The mass of the core 5 when the roll width W is different from 114 mm is obtained by converting W to 114 mm.
When the mass of the core 5 is less than 2.8 g, the basis weight of the core 5 is small, and the core may easily be crushed during the production of the toilet roll (log). When the mass of the core 5 exceeds 7.9 g, the basis weight of the core 5 becomes high, so that the core is less likely to be crushed, but the core becomes hard, which may lead to a decrease in core productivity and an increase in cost. be.
The mass of the core 5 is preferably 3.5-6.4 g, more preferably 4.4-5.2 g.

The outer diameter of the core 5 is preferably 20-52 mm. When the outer diameter of the core 5 is less than 20 mm, the core is less likely to be crushed, but it may be difficult to attach the toilet roll to the toilet holder. If the outer diameter of the core 5 exceeds 52 mm, the core may be easily crushed during manufacturing of the toilet roll (log).
The outer diameter of the core 5 is preferably 25-48 mm, more preferably 37-43 mm.

The roll density is 0.17-0.38 g/cm ³ , preferably 0.20-0.34 g/cm ³ , more preferably 0.23-0.30 g/cm ³ .
If the roll is wound too tightly (roll density is too high), the core will be easily crushed due to tight winding (high mass per volume). On the other hand, if the roll is wound too weakly, the embossment will not be crushed, but the diameter of the roll will increase, making it difficult to attach to the paper holder, or the winding force of the inner roll will be too weak, and the inner side of the roll will be in the axial direction. There is a risk that it may pop out and cause defective products. For this reason, the roll density was defined as a factor for expressing the winding strength of the roll.

Roll density is expressed as (roll mass without core)/(roll volume). The roll mass is the mass of the toilet roll 10 converted per roll width W of 114 mm. The roll volume is expressed by [{cross-sectional area of roll outer diameter (winding diameter DR) portion}-(core outer diameter portion cross-sectional area)]×roll width (assumed to be 114 mm). For example, when the roll mass per roll width of 114 mm is 328 g, the winding diameter is 118 mm, and the core outer diameter is 39 mm, the roll density = 328 g ÷ [{3.14 × (118 mm ÷ 2 ÷ 10) ² -3.14 × ( 39 mm÷2÷10) ² }×(114 mm÷10)]=0.30 g/cm ³ .
If the roll density is less than 0.17 g/cm ³ , the roll diameter DR exceeds 142 mm, making it difficult to fit in a toilet paper holder or the like, and the winding force of the inner roll becomes too weak, causing the inner roll side of the roll to become too weak. It may protrude in the axial direction (poor shape retention of the roll), resulting in a defective product. When the roll density exceeds 0.38 g/cm ³ , the core is easily crushed due to tight winding. In addition, the softness of the sheet may deteriorate, or the embossing provided on the toilet paper may be crushed, resulting in a decrease in cosmeticity during use.

<Unevenness>
The toilet roll 10 (toilet paper 10x) of the present invention has a plurality of irregularities. The unevenness can be applied, for example, by embossing. In the present invention, since the sheet is 1 ply, single embossing is performed.
Also, the emboss pattern (emboss size, depth, number, area ratio) can be changed as appropriate.

Hereinafter, embossing will be described as an example of unevenness.
Single embossing is formed by pressing the embossing projections of the embossing roll 151 only from one surface of the toilet paper 10x, as shown in FIG.
FIG. 2 is a cross-sectional view showing single embossments 2 provided on the toilet roll 10 (toilet paper 10x). In addition, in the example of FIG. 2, the toilet paper 10x consists of 1 ply, and the upper part of FIG. 2 corresponds to the roll surface 10a side. An embossing (single embossing) 2 is formed in which a concave portion 2R appears on the surface of the toilet paper 10x against which the embossing roll 151 is pressed (the surface in FIG. 2) and a convex portion 2P appears on the back surface.
In addition, Fig.2 (a) is the case where the embossing depth is deep, and FIG.2(b) is the case where the embossing depth is shallow.

In this case, the paper thickness t2 of the toilet paper 10x after embossing (this paper thickness reflects the distance between the non-embossed portion on the front surface of the toilet paper 10x and the embossed convex portion 2P on the back surface) is the same. However, the sheet obtained by calendering the base paper to a thickness of t1 is embossed so that the embossing depth (corresponding to the depth of the recessed portion of the unevenness) D is deepened. is soft and has an excellent texture. This is probably because the embossed unevenness in FIG. 2(a) is more pronounced, and the base paper has a higher bulk (lower density) relative to the thickness of the base paper, making it easier to deform and improving the softness of the sheet. .
In the case of FIG. 2(a), in order to increase the embossing depth D, it is necessary to reduce the paper thickness t1 per sheet by that amount to make the unevenness noticeable. The softness of the sheet is improved due to the strong performance.
Of course, embossing may be performed without performing calendering. In this case, the paper thickness of the sheet before embossing can be controlled by adjusting the pulp composition, beating conditions, crepe ratio, etc., so as to ensure the embossing depth.

On the other hand, if the surface of the toilet paper 10x is smoothed without being embossed, the surface is too smooth and crunchy, and the softness of the sheet is inferior. It should be noted that if the embossed concave portions 2R are provided on the roll outer side (roll surface 10a side) of the toilet paper 10x to which water tends to adhere when a warm-water washing toilet seat is used, etc., the concave portions 2R have a better feel than the convex portions. Improves sheet softness.

In addition, the means for ensuring the softness of the toilet paper (sheet) 10x is not limited to embossing, as long as it provides unevenness to the surface. good. Also, in this case, the depth of the concave portion of the unevenness should be in the range corresponding to the embossing depth D.

Further, the depth D of the concave portion of the unevenness is obtained by measuring using a microscope.
As a microscope, the product name "One-shot 3D measurement macroscope VR-3100" manufactured by KEYENCE can be used. The product name "VR-H1A" can be used as the observation/measurement/image analysis software for the image of the microscope. Measurement conditions are a magnification of 12 times and a visual field area of 24 mm×18 mm. Note that the measurement magnification and the visual field area may be appropriately changed depending on the size of the desired emboss.

First, as shown in FIG. 4, the longest part a of the fringe fr of the embossment is obtained. FIG. 5(a) shows the height profile on the XY plane by a microscope, and it can be seen that the height of the surface of the toilet paper is represented by shading. The dark colored portions in FIG. 5(a) indicate the individual embossments 2, and the longest part a of one embossment 2 can be discerned from FIG. 5(a). By drawing a line segment AB across this longest portion a, the height (measured cross-sectional curve) profile of the embossment 2 is obtained as shown in FIG. 5(b). Here, since the embossed convex portion (non-embossed portion) and concave portion can be identified from the color density of the XY plane image, the line segment AB should be determined so as to cross the portion where the convex portion and concave portion are adjacent to each other. Just do it.

Here, the height profile in FIG. 5(b) is a (measurement) cross-sectional curve S representing the unevenness of the actual toilet paper sample surface, but noise (such as the presence of fiber clumps on the surface of the toilet paper or the presence of fibers) It also includes sharp peaks that extend like whiskers and are caused by areas without fibers), and it is necessary to remove such noise peaks when calculating the height difference of unevenness.
Therefore, as shown in FIG. 6, a "contour curve" W is calculated from the cross-sectional curve S of the height profile. The minimum value sandwiched between points P1 and P2 is obtained and taken as the minimum depth value Min. Further, the average value of the depth values of the inflection points P1 and P2 is set as the maximum depth value Max.

In this way, the depth D of the concave portion of the unevenness is set to be the maximum value Max−the minimum value Min. Also, the distance (length) on the XY plane between the points of inflection P1 and P2 is defined as the length of the longest portion a. In addition, the "contour curve" is a shorter wavelength than λc: 800 μm from the cross-sectional curve (where λc is the "filter that defines the boundary between the roughness component and the waviness component" described in JIS-B0601 "3.1.1.2"). It is a curve obtained by removing the surface roughness component with a low-pass filter. Note that if λc is set equal to or greater than the interval P1 between adjacent embosses (this is called an emboss pitch), peaks may be recognized as noise, so λc is set to be less than the emboss pitch. For example, if the emboss pitch is 800 μm or less, λc is set to 250 μm. For the interval P1 between adjacent embosses, similarly obtain P1 and P2 for the next emboss connected to the left or right in FIG. be.

Similarly, in FIG. 5(a), the depth D of the concave portion of the unevenness is measured for the longest portion b in the direction perpendicular to the longest portion a, and the depth D of the concave portion of each unevenness of the longest portions a and b Among them, the larger value is adopted as the depth D of the concave portion of the unevenness. The above measurements are performed for arbitrary ten embossments 2 on the surface 10a of the toilet paper 10x, and the average value is adopted as the final depth D of the concave portion of the unevenness.
However, as shown in FIG. 8, when the embossment 2 is continuous in the flow direction (MD direction), the longest part a becomes the same as the winding length, and the height difference cannot be obtained, and the depth D of the recess is Cannot measure. Therefore, the depth D of the recess can be measured by drawing a line segment AB so as to straddle the emboss 2 in the width W direction perpendicular to the direction (MD direction) where the emboss 2 is connected.
Similarly, when the embossment 2 is continuous in the width W direction (CD direction), a line segment AB is drawn across the embossment 2 in the flow direction (MD direction) to measure the depth D of the recess.

In addition, when measuring the depth D of the recessed part of unevenness|corrugation, let the measuring surface be the surface 10a side.
Also, when determining the depth D of the recessed portion of the unevenness, when selecting any ten embossments (unevennesses) 2, from the end of the outer roll of the toilet roll 10 (the position where the toilet paper starts to be used), Any 10 of the embossments 2 arranged along the width direction in a portion corresponding to 10% of the roll length of the toilet roll 10 (for example, when the roll length is 150 m, the portion of 150 m × 10% = 15 m from the end) choose. Moreover, when there are less than ten embossments 2 in the width direction W, the embossments 2 of the insufficient number may be selected from the group of the embossments 2 adjacent to the embossment 2 on the outer winding side or the inner winding side. In addition, when the embossing 2 to be measured hits the perforation, the group of the embossing 2 on the outer winding side adjacent to the perforation is measured.

The depth D of the concave portion of the unevenness is preferably 0.01 to 0.42 mm, more preferably 0.04 to 0.37 mm, still more preferably 0.08 to 0.32 mm.
If the depth D is smaller than the above range, the degree of unevenness is reduced, the bulk is lowered (the density is increased), and it may be difficult to improve the softness of the sheet. If the depth D exceeds the above range, the unevenness becomes too pronounced, the bulk becomes too high (the density becomes too low), the roll diameter DR becomes too large, and it becomes difficult to attach the toilet roll 10 to the paper holder. There is

The hardness of the core 5 is preferably 0.4-6.9 mm, more preferably 0.6-4.4 mm, still more preferably 1.7-2.9 mm.
If the hardness of the core is less than 0.4 mm, the productivity of the core may deteriorate. This is because the basis weight of the core is too high and the strength becomes too high, making it difficult to bend the core sheet into a cylindrical shape. If the hardness of the core exceeds 6.9 mm, the core may be crushed when the toilet roll is manufactured. This is because the strength of the core becomes too low due to reasons such as a low basis weight of the core, and the core is likely to be crushed.

The hardness of the core 5 is measured using a compression tester (handy compression tester KES-G5 manufactured by Kato Tech Co., Ltd.) as follows. First, the core 5 is placed horizontally on a hard stand so that the axis is horizontal. Next, the KES-G5 compressor (area 2.0 cm ² ) is pushed into the center of the outer surface of the core 5 from above at a speed of 10 mm/min. The pressing depth when the pressure of the compressor pressing the roll is 0.5 gf/cm ² is T0, the pressing depth when the pressure is 250 gf/cm ² is Tm, and (Tm−T0) is the hardness of the core 5. do. If this value is large, it means that the core is easily crushed. The measurement is performed 5 times using 5 cores (each core is measured once), and the measurement results are averaged.

The ratio represented by (hardness of core)/(roll density) is preferably 1.4 to 23.0 mm/(g/cm ³ ), more preferably 2.5 to 16.0 mm/(g/cm 3 ). cm ³ ), more preferably 4.0 to 12.0 mm/(g/cm ³ ).
When the roll density is within the above range and the ratio is less than 1.4 mm/(g/cm ³ ), the hardness of the core relative to the roll density is low and the strength of the core is unnecessarily high. This may result in an increase in the cost of the core.
When the roll density is within the above range and the ratio exceeds 23.0 mm/(g/cm ³ ), the hardness of the core relative to the roll density is high, and the core may be easily crushed.

The sheet (toilet paper) 10x has a dry machine direction (MD) tensile strength DMDT (Dry Machine Direction Tensile strength) based on JIS P8113, preferably 2.5 to 7.5 N / 25 mm, more preferably 3.0. ~6.0 N/25 mm, more preferably 3.5 to 4.5 N/25 mm.
DMDT is measured by cutting out a strip-shaped test piece having a width W of 25 mm and a length of 250 mm in which the MD direction (longitudinal direction perpendicular to the width W) of the sheet (toilet paper) 10x is the longitudinal direction. The distance between the grips of the tensile tester is set to 100 mm, and the tension is measured in the MD direction at a tensile speed of 300 mm/min. At this time, perforations should not be included in the 100 mm gap between grippers.

The DCDT (Dry Cross Direction Tensile strength) of the toilet paper 10x in the dry cross direction (CD) based on JIS P8113 is preferably 0.7 to 2.3 N/25 mm, more preferably 0.8 to 1.5 mm. 8 N/25 mm, more preferably 1.0 to 1.5 N/25 mm.
DCDT is a strip-shaped test piece with a length of 114 mm (sheet width) with the CD direction (longitudinal direction parallel to the width W) of the sheet (toilet paper) 10x as the longitudinal direction, and the width W is 25 mm. do. The distance between the grips of the tensile tester is set to 100 mm, and the tension is measured in the CD direction at a tensile speed of 300 mm/min. Moreover, when the roll width (sheet width) is small and 114 mm cannot be secured, the length of the test piece may be used as the roll width. In addition, if the roll width (sheet width) is small and it is not possible to secure a gap of 100 mm between the grippers, this gap should be {(roll width) - (length of the sheet held by the grips x 2)} mm. Also good.

If the DMDT or DCDT is less than the above value, it may be easily broken and not suitable for practical use. If the DMDT or DCDT is higher than the above values, the sheet becomes hard and the softness of the sheet may be impaired.
The flow direction of the toilet paper is defined as "longitudinal direction", and the direction perpendicular to the flow direction is defined as "lateral direction".

The basis weight per sheet of the toilet paper 10x is preferably 12-22 g/m ² , more preferably 15-21 g/m ² , still more preferably 17-20 g/m ² .
The sheet thickness is preferably 0.4 to 1.3 mm/10 sheets, more preferably 0.5 to 1.2 mm/10 sheets, and still more preferably 0.6 to 1.1 mm/10 sheets.
When the grammage and paper thickness of the sheet are set within the above ranges, the roll length and roll diameter DR can be easily adjusted within the above ranges, which is preferable. In addition, the tactile sensation when using the toilet paper is improved.
As a method for adjusting the grammage and paper thickness of the sheet within the above ranges, the calendering conditions (paper thickness and specific volume after calendering) and embossing conditions of the base paper web are defined.

If the basis weight per sheet of toilet paper 10x is less than 12 g/m ² or the paper thickness is less than 0.4 mm/10 sheets, the strength and usability (bulkiness) will decrease. Sometimes. When the basis weight per sheet of toilet paper 10x exceeds 22 g/m ² or the paper thickness exceeds 1.3 mm/10 sheets, the toilet paper becomes thick, the winding diameter DR of the roll exceeds 142 mm, and the toilet paper It may be difficult to fit in the paper holder.

The specific volume of the toilet paper is preferably 2.5-6.9 cm ³ /g, more preferably 2.8-6.4 cm ³ /g, still more preferably 3.1-5.9 cm ³ /g.
If the specific volume is less than 2.5 cm ³ /g, the softness of the sheet may be poor, or the bulk (bulkiness) may be lowered, resulting in poor moisture absorption. On the other hand, when the specific volume exceeds 6.9 cm ³ /g, the bulk of the sheet increases, but the thickness of the sheet increases and the winding diameter may increase.

FIG. 3 shows an example of the roll winding machine 150 . The base paper roll is calendered to become a base paper 114 (sheet thickness t1). This original roll 114 is set in a roll winding machine 150, subjected to single embossing by an embossing unit (embossing roll) 151, and then wound by a winding mechanism 153 around the wide toilet paper raw roll 10W having a winding diameter. captured and logged. After that, the original roll 10W is cut into a predetermined width (114 mm, etc.) by a log saw to obtain the toilet roll 10 .

The speed at which a log (raw roll 10W) is cut to a predetermined width (114 mm, etc.) with a log saw is preferably 10 to 150 cuts/min, more preferably 20 to 100 cuts/min, and still more preferably 25 to 70 cuts/min. is. Here, the log saw is a disk-shaped rotary blade that sequentially cuts one end of the log that is sent out. indicate what to do.
Since the toilet roll of the present invention is long and the roll density is defined in the above range, if the cutting speed of the log saw is less than 10 cuts/min, bias cut (the roll is cut obliquely) may occur, resulting in poor quality. . On the other hand, when the cutting speed of the log saw exceeds 100 cuts/min, the blade of the log saw tends to generate heat, the blade is deformed, and the toilet roll is bias-cut, resulting in poor quality.

In addition, a plurality of logs may be arranged in parallel in the axial direction and cut at once with a log saw. There are three. If the number of logs exceeds 5, the blade of the log saw tends to heat up, the blade is deformed, and the toilet roll is bias-cut, resulting in poor quality.
Since the cutting speed of the log saw is the number of cuts, it does not change even if the number of logs changes.

The degree of bias cut is preferably 5 mm or less, more preferably 4 mm or less, even more preferably 3 mm or less, and most preferably 2 mm or less.
The degree of bias cut is measured as follows. First, the width of the roll is measured at one position in the circumferential direction of the roll. Next, the roll is rotated 90 degrees in the circumferential direction from the initial measurement position, and the width of the roll is similarly measured. In this manner, four locations are measured at 90-degree intervals in the circumferential direction of the roll, and the difference between the maximum value and the minimum value of the roll width is taken as the degree of bias cut. In addition, an average value obtained by measuring 10 rolls is used.

It should be noted that the diameter of the log saw blade is reduced as it is used, but the diameter when cut with the log saw is preferably 80% or more, more preferably 90% or more, more preferably 90% or more of the unused (new) blade. Keep above 95%. Since the toilet roll of the present invention is long and the roll density is defined within the above range, the core tends to be crushed when the blade diameter becomes smaller due to continued use of the blade.

The roll winding machine 150 is roughly classified into two types, a surface type and a center type. The surface method is a method of winding while supporting a roll to be wound from the outside by a plurality of separate driving rolls, and the wound toilet roll 10 can be easily controlled in diameter and can be produced at a higher speed. The center method is a method of winding by driving a shaft passed through the center of the winding roll, and the wound toilet roll 10 becomes a relatively soft product and is suitable for delicate embossed products. In the present invention, the film can be wound by any method, but the surface method is preferred.
In addition, the machine winder 100 of FIG. 7 is incorporated in the roll winding machine 150, or both (2 stacks) or one (1 stack) of the calendars 101 and 102 are incorporated in the roll winding machine 150, and the roll winding processing is performed. Calendering and embossing may be performed on the machine in this order.

The depth D of the concave portion of the unevenness can be controlled by appropriately adjusting the nip width of the rubber roll (see FIG. 3) facing the embossing roll 151 . The nip width is preferably 20 to 50 mm, more preferably 25 to 45 mm, still more preferably 30 to 40 mm, although it varies depending on the properties of the roll. If the nip width exceeds 50 mm, the embossing becomes too strong and the difference between the front and back becomes large, or the paper thickness becomes large and the winding diameter DR of the roll becomes large. On the other hand, if the nip width is less than 20 mm, the embossing may become weak and the softness of the sheet may deteriorate. The nip width can be measured using carbon paper. As for the measurement method, first, the nip of the embossing roll is released, and carbon paper and general copy paper are placed on top of each other. The embossing roll is then nipped. Then release the nip and remove the carbon paper and copy paper. Since the color of the carbon paper that was nipped by the embossing roll is transferred to the copy paper, the nip width can be measured.
The depth D of the concave portion of the unevenness can be adjusted by narrowing the nip width if the unevenness of the embossing roll is deep and widening the nip width if the unevenness of the embossing roll is shallow.

Printing, embossing, perforation, tail sealing, and cutting to a predetermined width (114 mm, etc.) can be simultaneously performed by the roll winding machine, and the toilet roll 10 can be manufactured. Furthermore, after that, it can be film-wrapped to produce a toilet roll package.

The toilet paper may consist of 100% by weight wood pulp and may contain waste paper pulp, non-wood pulp and deinked pulp. In order to obtain the target quality, the content of NBKP (softwood bleached kraft pulp) is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, and still more preferably 0 to 10% by mass. Also, the content of LBKP (bleached hardwood kraft pulp) is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and still more preferably 50 to 70% by mass.
In addition, the content of waste paper pulp derived from liquid beverage cartons (milk cartons, sake packs, etc.) is preferably 0 to 60% by mass, more preferably 10 to 50% by mass, and still more preferably 20 to 45% by mass. is preferably 40 to 100% by mass, more preferably 50 to 90% by mass, still more preferably 55 to 80% by mass.
Waste paper pulp derived from liquid drink cartons (milk cartons, sake cartons, etc.) is mainly softwood pulp, which has the advantage of making it easy to ensure the strength of toilet paper. Since it affects the quality, it is preferable to set the content in the above range.
Pulp produced from the genus Eucalyptus of the family Myrtaceae, typified by Eucalyptus grandis and Eucalyptus globulus, is preferable as the LBKP material.

In addition, 25 parts by mass or less of deinked pulp derived from newspapers, magazines, etc. can be blended with 100 parts by mass of waste paper pulp derived from NBKP, LBKP and milk cartons. The content of deinked pulp in toilet paper (sheet) when 25 parts by mass of deinked pulp is added is 25 parts by mass/(100 parts by mass + 25 parts by mass) x 100 = 20% by mass. The content of deinked pulp is 0 to 20% by mass, preferably 0 to 10% by mass, more preferably 0 to 5% by mass or less, most preferably 0% by mass. Since the deinked pulp is also waste paper, the quality varies widely. Moreover, deinked pulp usually contains a fluorescent dye, and if the content exceeds 20% by mass, the fluorescent dye is contained in a large amount, which is not preferable.

When the deinked pulp contains a fluorescent dye, the difference Δ between the whiteness value of toilet paper (sheet) under UV-in conditions and the whiteness value under UV-cut conditions increases. Here, UV-in is the whiteness in conformity with ISO 2470 when the C light source (including ultraviolet light) specified by CIE (International Commission on Illumination) is applied to the surface side of the sheet. UV-cut is the degree of whiteness conforming to ISO 2470 when the surface side of the sheet is irradiated with a C light source through a filter that cuts ultraviolet light with a wavelength of 420 nm or less. The difference Δ=(whiteness UV-in)−(whiteness UV-cut).
The difference Δ is preferably 0.0 to 2.5 points, more preferably 0.0 to 1.5 points, still more preferably 0.0 to 1.0 points, and most preferably 0.0 to 0.5 points. is. The whiteness can be measured according to ISO 2470 using a high-speed spectrophotometer CMS-35SPX manufactured by Murakami Color Research Laboratory.

In order to ensure proper strength of the toilet paper, it is possible to adjust the strength by blending the raw materials and beating the pulp fibers by ordinary means. For beating to obtain the target quality, commercially available virgin pulp is subjected to a Canadian standard freeness measured by JIS-P8121 of 0 to 200 ml, more preferably 0 to 150 ml, and still more preferably 10 to 100 ml. Reduce water content.

Toilet paper can be made by blending softwood kraft pulp and broadleaf kraft pulp having a certain range of fiber length and fiber roughness in the case of using a virgin raw material for the stock. Depending on the quality required for the final product, additives to paper materials include softening agents including debonder softening agents, bulking agents, dyes, dispersants, dry paper strength agents, drainage improvers, pitch control agents, absorbency Enhancers and the like can be used. Also, it is preferable not to use a wet paper strength agent.
When waste paper raw materials are used as toilet paper, the same treatment as in the case of the virgin system is performed.
The details of the toilet paper manufacturing method will be described later.

Toilet paper can be manufactured, for example, in the order of (1) papermaking and creping, (2) calendering, and (3) embossing and roll winding, as follows. Of these, (3) has already been explained, so its explanation is omitted.

(1) papermaking and creping;
First, a web is made from the stock on the wire part of a known paper machine and transferred to the felt of the press part. Examples of the wire part system include a round mesh system, a fourdrinier system, a suction breast system, a short mesh system, a twin wire system, and a crescent former system.
Then, the web is mechanically compressed with a suction pressure roll, a pressure roll without suction, a press roll, or the like, or dehydration is continued by a dehydration method such as through-drying with hot air. Suction pressure rolls or pressure rolls without suction are also used as a means of moving the web from the press part to the Yankee dryer.

The web transferred to the Yankee dryer is dried by the Yankee dryer and the Yankee dryer hood, creped by a creping doctor, and wound up on a reel part.
Creping is the mechanical compression of paper in the machine direction (the direction of sheet travel on the paper machine). When the toilet paper web is manufactured, the web on the Yankee dryer is peeled off by the creping doctor and wound on the reel part. ) forms a crepe with a creping doctor.
The quality required for toilet paper, that is, bulkiness, softness, water absorbency, surface smoothness, aesthetics (crepe shape), etc., are affected by the speed difference. Depending on conditions such as the speed difference, the basis weight of the web on the reel after creping is approximately 13 to 24 g/m ² , which is higher than the basis weight of the web on the Yankee dryer before creping. The basis weight is preferably 16-23 g/m ² , more preferably 18-22 g/m ² . When the above range is exceeded, the paper may become stiff due to its high strength, and when it is less than the above range, the strength may be weak and the paper may be easily torn.

Here, the crepe ratio based on the speed difference between the Yankee dryer and the reel is defined by the following equation.
Crepe rate (%) = 100 x (Yankee dryer speed (m/min) - reel speed (m/min)) / reel speed (m/min)
Quality and workability are largely determined by the creping conditions, and operating conditions that optimize the creping conditions are important matters for those skilled in the art. The crepe rate when producing toilet paper in the present invention is preferably 10-50%, more preferably 15-40%, and most preferably 20-35%.

(2) Calender Processing FIG. 7 shows an example of the machine winder 100 . As described above, the reel 112 wound by the reel part after creping is set in the machine winder 100 and calendered in two stages in the order of the calender 101 for the first stack and the calender 102 for the second stack. Of course, either the calender machine 101 of the first stack or the calender machine 102 of the second stack may carry out the calendering process at only one stage. It is also possible to perform calendar processing with an on-machine calendar.
The thickness of the toilet paper before embossing (after calendering) is preferably 0.5 to 1.5 mm/10 sheets, more preferably 0.6 to 1.3 mm/10 sheets, still more preferably 0.7 to 1 .1 mm/10 sheets. In addition, the specific volume of the toilet paper in the original fabric 114 before embossing (after calendering) is preferably 2.7 to 6.8 cm ³ /g, more preferably 3.0 to 6.5 cm ³ /g, and even more preferably. is 3.2 to 6.0 cm ³ /g.

Note that the thickness of the toilet paper before embossing is the thickness of the roll 114 after calendering in FIG. 7, and corresponds to the thickness t1 in FIG. However, as will be described later, since the paper thickness is a value measured with a measurement load of 3.7 kPa, it does not accurately reflect the paper thickness t1 in FIG.
The thickness of the toilet paper after embossing shown in Tables 1 and 2 corresponds to the thickness t2 of FIG. It's not what I did.
On the other hand, the depth (embossing depth) D of the concave portion of the unevenness is measured in the state where the embossing is not compressed. Therefore, the depth D of the concave portion of the unevenness is significantly larger than the value calculated from the paper thicknesses t1 and t2 (this value is the value obtained by compressing the emboss with a measurement load of 3.7 kPa).

Each of the calenders 101 and 102 preferably consists of two metal rolls, but one of the two rolls may be an elastic roll so that soft calendering can be performed.
The linear pressure of the calender is preferably 2.5 to 7.5 kgf/cm, more preferably 3.0 to 7.0 kgf/cm. If the linear pressure exceeds the above range, the bulk becomes small and the softness may be inferior. Moreover, when the wire thickness is less than the above range, the bulk becomes large, and the winding diameter DR of the roll becomes large. Also, it is preferable that the linear pressure is higher in the second stack than in the first stack.
During calendering, the draw can be adjusted accordingly. The draw between the reel 112 before ply-up and the web 114 after calendering is preferably 100-110%.

The roll 114 after calendering is embossed by, for example, the roll winding machine 150 shown in FIG. 3 to obtain the toilet roll 10 . In the roll winding machine 150 shown in FIG. 3, the roll density is used to sequentially wind the sheet by pressing the raw roll 10W from the outer peripheral side when winding the wide toilet paper raw roll 10W by the winding mechanism 153. The pressing force of the rider roll 154 can be adjusted by setting it within a predetermined range.

It is needless to say that the present invention is not limited to the embodiments described above, but extends to various modifications and equivalents within the spirit and scope of the present invention.

The content of the pulp composition (% by mass) was 10% NBKP, 60% LBKP, and 30% waste paper pulp derived from liquid beverage cartons, and no deinked pulp was included. -Toilet paper and toilet rolls shown in Table 3 were produced.

The following evaluations were performed.
Dry longitudinal tensile strength DMDT and dry transverse tensile strength DCDT: Based on JIS P8113, the maximum load until breakage was measured for toilet paper (one ply). Specific test pieces and measurement methods are as described above.
Basis weight: Measured based on JIS P8124 and taken as per sheet.
Paper thickness: Measured using a thickness gauge (dial thickness gauge "PEACOCK" manufactured by Ozaki Seisakusho). The measurement conditions were a measurement load of 3.7 kPa and a probe diameter of 30 mm. For both webs and rolls before and after calendering, 10 sheets were piled up and measured. Also, the measurement was repeated 10 times and the measurement results were averaged.

Specific volume: The paper thickness per sheet was divided by the basis weight per sheet, and expressed as volume cm ³ per unit g.
Weight of roll without core and weight of core: Measured using an electronic balance. First, the weight of the roll containing the core was measured, then the sheet was removed from the roll and the weight of the remaining core was measured. The weight of the core was subtracted from the weight of the roll containing the core to obtain the weight of the roll without the core. The roll mass was obtained by measuring 10 rolls and averaging the measurement results to obtain a value per roll.
Roll winding diameter DR, core outer diameter DI: Measured using a diameter meter rule manufactured by Muratec KDS Co., Ltd. Ten rolls were measured and the measurement results were averaged.
The roll density, embossing depth D, core apparent basis weight, and core hardness were measured by the methods described above. For the roll density, 10 rolls used for measuring the winding diameter DR of the roll were measured, and the measurement results were averaged.
Winding length: The length of 10 sheets between perforations was actually measured. After that, the number of sheets in the roll was actually measured. After that, it was determined by proportional calculation from the length of 10 sheets and the number of sheets. For example, if the length of 10 sheets is 2.275 m and the number of sheets is 660, then 2.275 m×(660/10)=150 m.

Sensory evaluation was performed by 20 monitors. Evaluation criteria were performed on a scale of 5 points. It is good if the evaluation criteria is 3 points or more.
Basis weight, tensile strength, thickness (paper thickness), roll mass and core mass, specific volume, roll diameter DR, core outer diameter DI, core hardness, roll density, roll length, emboss depth was measured after being kept in an equilibrium state under the temperature and humidity conditions (23±1° C., 50±2% RH) specified in JIS-P8111.

The results obtained are shown in Tables 1-3.

As is clear from Tables 1 to 3, in the case of each example in which the roll length, roll diameter, apparent basis weight of the core, and roll density of the toilet roll are within predetermined ranges, the tactile sensation is good and per roll It was possible to lengthen the winding length of the core and to prevent the core from collapsing without impairing the cost and productivity.
Furthermore, in each example in which the sheet strength (DMDT) was 2.5 to 7.5 N/25 mm, compared to Example 22 in which the sheet strength (DMDT) was less than 2.5 N/25 mm, the sheet was less likely to tear. The bitterness was excellent. However, Example 22 also poses no practical problem.
In addition, in each example in which the sheet strength (DMDT) was 2.5 to 7.5 N/25 mm, the sheet was softer than Example 23 in which the sheet strength (DMDT) exceeded 7.5 N/25 mm. was excellent. However, Example 23 also poses no practical problem.

On the other hand, in the case of Comparative Example 1 in which the winding length was less than 105 m and the winding diameter was less than 100 mm, the roll replacement frequency increased.
In the case of Comparative Example 2 in which the winding length exceeded 210 m and the winding diameter exceeded 142 mm, the diameter of the roll increased and it became difficult to fit in the toilet paper holder.

In Comparative Example 3, in which the apparent basis weight of the core was less than 220 g/m ² , the core collapsed during roll production.
In Comparative Example 4, in which the apparent basis weight of the core exceeded 570 g/m ² , the strength of the core was unnecessarily high, leading to an increase in core cost and poor core productivity.

In the case of Comparative Example 5, which was manufactured under the same manufacturing conditions as in Example 18 except that no embossing was provided, the sheet was harder and inferior in softness than in Example 18 because there was no embossing. Moreover, the roll density exceeded 0.38 g/cm ³ and the core was crushed.

In the case of Comparative Example 6 in which the embossing depth exceeded 0.42 mm, the roll diameter exceeded 142 mm due to excessive bulkiness, and the roll diameter became too large to fit in the toilet paper holder. In addition, in the case of Comparative Example 6, the roll density was less than 0.17 g/cm ³ .

In addition, in the case of Comparative Example 3, the ratio exceeded 23.0 mm/(g/cm ³ ), and the core was easily crushed. Moreover, in the case of Comparative Example 4, the ratio was less than 1.4 mm/(g/cm ³ ), and the productivity and cost of the core were inferior.

When commercial products 1 and 2 were similarly evaluated, the winding length was less than 105 m, and the frequency of roll replacement increased.

2 Emboss (unevenness)
10 toilet roll 10x toilet paper D embossing depth (depth of recesses)

Claims (6)

A toilet roll obtained by winding one-ply toilet paper in a roll shape having a plurality of unevennesses in which one surface is a convex portion and the corresponding opposite surface is a concave portion,
The winding length is 105 to 210 m, the winding diameter is 100 to 142 mm, the apparent basis weight of the core is 220 to 570 g/m ² ,
a roll density of 0.17 to 0.38 g/cm ³ ;
The mass of the core per roll width of 114 mm is 3.5 to 6.4 g,
The core is placed horizontally on a hard stand so that the axis is horizontal, and a compressor (area 2.0 cm ² ) is pushed into the center of the outer surface of the core from above at a speed of 10 mm/min. T0 is the pushing depth when the pressure is 0.5 gf/cm ² , Tm is the pushing depth when the pressure is 250 gf/cm ² , and (Tm−T0) is the hardness of the core. A toilet roll having a hardness of 0.4 to 6.9 mm (excluding 0.6 to 4.8 mm). 2. The toilet roll according to claim 1, wherein the recesses of the unevenness have a depth of 0.01 to 0.42 mm. 3. The toilet roll according to claim 1, wherein the ratio represented by (hardness of core)/(roll density) is 1.4 to 23.0 mm/(g/cm ³ ) . The toilet roll according to any one of claims 1 to 3, wherein the dry longitudinal tensile strength DMDT of the toilet paper based on JIS P8113 is 2.5 to 7.5 N/25 mm . The toilet roll according to any one of claims 1 to 4, wherein the dry transverse tensile strength DCDT of the toilet paper based on JIS P8113 is 0.7 to 2.3 N/25 mm . The toilet roll according to any one of claims 1 to 5 , wherein the unevenness is embossed .

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