JP6952554B2 - Printed matter paper - Google Patents

Description

The present invention relates to a printed matter sheet.

Newsprint is usually printed in large quantities and at high speed by an offset printing machine or the like (see Patent Documents 1 and 2). The newspapers printed by the printing machine are sequentially stacked, and a large number of printed newspapers are stacked. At this time, in order to prevent the bottom newspaper from being soiled or scratched, a newspaper is laid and the newspaper is stacked on the newspaper.

Japanese Unexamined Patent Publication No. 2009-013288 Japanese Unexamined Patent Publication No. 2008-302650

The above-mentioned laying paper for printed matter such as newspaper is required to have sufficient strength to withstand the friction between the heavy printed matter and the conveyor during transportation. However, if a strong sheet of paper is simply used, there is an inconvenience that the sheet of paper may be curled when it is used as the sheet of paper. Such curling of the paper sheet causes, for example, a paper jam (jamming) in the paper feeding device, a trouble of double feeding of the paper sheet itself, and the like.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a printed matter sheet in which curling is suppressed.

Invention was made to solve the aforementioned problems is a printed material laid paper comprising a bedding sheet when stacking a plurality of paper that has been printed, vertical Clark stiffness is, 8 cm ^3/100 or more 50 cm ³ / It is a paper sheet for printed matter, which is 100 or less and has a vertical elongation of 5% or more and 10% or less.

It is presumed that the curl of the paper sheet that occurs when the plurality of printed papers (printed matter) are laminated is caused by shrinkage / deformation due to the difference between the front and back sides of the water content of the paper sheet itself and the bias of the fiber orientation. That is, in the conventional paper, it is presumed that the paper is curled as the paper itself shrinks and deforms. On the other hand, in the printed matter paper, the rigidity (Clark stiffness) is low and the elongation is large, so that the deformation of the paper is minimized and the curl is absorbed by the elasticity of the paper itself. As a result, the occurrence of curl in the printed matter paper is suppressed. Further, the printed matter sheet in which the occurrence of curl is suppressed in this way is excellent in handleability when transporting the printed matter.

In the printed matter paper, the tensile strength in the vertical direction is preferably 2.8 kN / m or more and 10 kN / m or less, and the tear strength in the vertical direction is preferably 730 mN or more and 1,200 mN or less. When the printed matter sheet has such tensile strength and tear strength, sufficient strength is provided, and the suitability of a large amount of printed matter as a sheet material is further enhanced.

In the printed matter paper, the Beck smoothness is preferably 1 second or more and 30 seconds or less. When the printed matter sheet has such smoothness, the slippage of the printed matter can be suppressed, and the suitability of the printed matter as the sheet material is further enhanced.

The printed matter base paper preferably has a basis weight of 40 g / m ² or more and 100 g / m ² or less. When the basis weight is within the above range, it is possible to achieve both rigidity and strength in a better state.

In the printed matter paper, the sliding angle in the vertical direction is preferably 15 degrees or more and 35 degrees or less. When the sliding angle is within the above range, it is possible to prevent the load from collapsing when the stacked printed matter such as newspaper is conveyed on the belt conveyor.

It is preferable that the paper sheet for printed matter contains unbleached kraft pulp, and the content ratio of unbleached kraft pulp in the total pulp is 90% by mass or more. In this way, by using unbleached kraft pulp as the main component, the strength can be further increased.

According to the present invention, it is possible to provide a printed matter sheet in which the generation of curl is suppressed.

Printed material laid paper according to an embodiment of the present invention is a printed material laid paper comprising a bedding sheet when stacking a plurality of paper that has been printed, vertical Clark stiffness is, 8 cm ^3/100 over 50cm ^3/100 or less, the longitudinal elongation, characterized in that 10% or less than 5%. According to the printed matter paper, the occurrence of curl when used as the printed matter paper is suppressed, and the occurrence of troubles such as paper jams can be suppressed.

The plurality of printed papers are not particularly limited, but newspapers are preferable. Normally, newspapers are printed in large quantities at high speed by a high-speed printing machine, and a large amount of these are stacked on the paper sheet, so that the paper sheet is likely to be curled. The inconvenience that paper jams are likely to occur in automatic tailoring machines and the like becomes remarkable. Therefore, when the printed matter laying paper is used as the newspaper laying paper, there is a great advantage that the occurrence of curl of the laying paper itself can be suppressed.

(quality)
The upper limit of the longitudinal Clark stiffness of the printed material laid paper is 50 cm ^3/100, preferably ^{45cm 3/100, 40cm 3/} 100 is also more preferable, sometimes even more preferably 35 cm ^3/100 , it may further preferably 30 cm ^3/100. Since the paper for printed matter has such a low rigidity (Clark stiffness), the paper should alleviate the deformation of the printed matter made of paper such as newspaper piled on the paper in combination with the magnitude of elongation. It is possible to suppress the occurrence of curl of the paper sheet. On the other hand, the lower limit of the Clark stiffness ^is 8 cm 3/100, preferably 10 cm ^3/100, there may 20 cm ^3/100 are more preferred. If the clerk stiffness in the vertical direction is less than the above lower limit, the stiffness may become too weak and the handleability as a paper sheet may deteriorate. In addition, "Clark stiffness" means a value measured in accordance with JIS P8143 (2009).

The lower limit of the vertical elongation of the printed matter sheet is 5%, preferably 5.8%, and more preferably 7%. Since the printed matter sheet has such a large elongation, it is possible to alleviate the deformation of the sheet sheet itself in combination with the low rigidity, and it is possible to suppress the occurrence of curl of the sheet sheet. On the other hand, the upper limit of this growth is 10%, preferably 9.6%. If the elongation in the vertical direction exceeds the above upper limit, it may be too soft and the handleability as a paper sheet may be deteriorated, or conversely, curling may easily occur. “Elongation” refers to the value of tensile elongation at break measured in accordance with JIS P8113 (2006).

Clark stiffness and elongation in the printed matter paper can be adjusted by adjusting the degree of elongation using, for example, kraft stretched paper as described later.

The lower limit of the longitudinal tensile strength of the printed matter sheet is preferably 2.8 kN / m, more preferably 3.8 kN / m, and even more preferably 5 kN / m. By setting the tensile strength of the printing paper to be equal to or higher than the above lower limit, sufficient strength is provided, durability is increased, and the suitability of a large amount of printed matter as a paper is enhanced. On the other hand, as the upper limit of this tensile strength, 10 kN / m is preferable, and 8.1 kN / m is more preferable. The "tensile strength" refers to a value measured in accordance with JIS P8113 (2006).

The lower limit of the specific tensile strength in the vertical direction of the printed matter sheet is preferably 60 N · m / g, more preferably 65 N · m / g, and even more preferably 70 N · m / g. Further, the lower limit of the specific tensile strength in the lateral direction is preferably 28 N · m / g, more preferably 30 N · m / g, and even more preferably 32 N · m / g. By setting the specific tensile strength in the vertical and horizontal directions to be equal to or higher than the above lower limit, the strength of the paper sheet can be further increased. The upper limit of the specific tensile strength in the vertical direction may be, for example, 100 N · m / g. Further, the upper limit of the specific tensile strength in the lateral direction may be, for example, 50 N · m / g. The "specific tensile strength" refers to a value measured in accordance with JIS P8113 (2006).

The lower limit of the tear strength in the vertical direction of the printed matter paper is preferably 730 mN, more preferably 850 mN, and even more preferably 900 mN. By setting the tear strength of the printing paper to be equal to or higher than the above lower limit, sufficient strength is provided, durability is increased, and the suitability of a large amount of printed matter as a paper is enhanced. On the other hand, as the upper limit of the tear strength, 1,200 mN is preferable, and 1032 mN is more preferable. The “tear strength” refers to a value measured in accordance with JIS P8116 (2000).

Vertical lower limit of the ratio tear strength of the printed material laid paper is preferably from 12mN · ^m 2 / g, more preferably 13mN · ^m 2 / g, more preferably 14mN · ^m 2 / g. The lower limit of the ratio tear strength of the transverse direction is preferably 20mN · ^m 2 / g, more preferably 22mN · ^m 2 / g, more preferably 24mN · ^m 2 / g. By setting the specific tear strength in the vertical and horizontal directions to be equal to or higher than the above lower limit, the strength of the paper sheet can be further increased. The upper limit of the relative tear strength in the vertical direction may be, for example, 30 mN · m ² / g. Further, the upper limit of the specific tear strength in the lateral direction may be, for example, 50 mN · m ² / g. The "specific tear strength" refers to a value measured in accordance with JIS P8116 (2000).

The lower limit of the specific tensile stiffness in the vertical direction of the printed matter paper is preferably 4.0 kN · m / g, more preferably 4.2 kN · m / g, and even more preferably 4.4 kN · m / g. Further, the lower limit of the specific tensile stiffness in the lateral direction is preferably 2.8 kN · m / g, more preferably 3.0 kN · m / g, and even more preferably 3.2 kN · m / g. By setting the vertical and horizontal specific tensile stiffness to be equal to or higher than the above lower limit, handleability and workability can be improved. The upper limit of the specific tensile stiffness in the vertical direction may be, for example, 8 kN · m / g. Further, the upper limit of the specific tensile stiffness in the lateral direction may be, for example, 6 kN · m / g. The "specific tensile stiffness" refers to a value measured in accordance with ISO / DIS 1924-3.

As the lower limit of the Beck smoothness of the printed matter sheet, 1 second is preferable, and 5 seconds is more preferable. On the other hand, as the upper limit of the Beck smoothness, 30 seconds is preferable, 20 seconds is more preferable, and 18 seconds is further preferable. When the printed matter sheet has such smoothness, it is possible to suppress slippage of the printed matter and collapse of the stacked printed matter, and the suitability as the printed matter sheet is further enhanced. The "Beck smoothness" refers to a value measured in accordance with JIS P8119 (1998).

As the lower limit of the sliding angle in the vertical direction of the printed matter paper, 15 degrees is preferable, 18 degrees is more preferable, and 24 degrees is further preferable. When the sliding angle is at least the above lower limit, it is possible to prevent the load from collapsing when the stacked printed matter such as newspaper is conveyed on the belt conveyor. On the other hand, the upper limit of the sliding angle is preferably 35 degrees, more preferably 30 degrees. The "sliding angle" refers to a value measured in accordance with the inclination method described in JIS P8147 (2010).

As the lower limit of the basis weight of the printed matter sheet, 40 g / m ² is preferable, and 60 g / m ² is more preferable. On the other hand, as the upper limit of the basis weight, 100 g / m ² is preferable, and 80 g / m ² is more preferable. When the basis weight of the printed matter sheet is within the above range, it is possible to achieve both rigidity and strength in a better state. The "basis weight" refers to a value measured in accordance with JIS P8124 (2011).

(Manufacturing method, etc.)
The printed matter laying paper is not particularly limited in other configurations as long as it has the above-mentioned Clark stiffness and elongation, but it may be kraft paper from the viewpoint of having sufficient strength and the like. preferable. Among them, kraft stretched paper, which is kraft paper No. 5 type 1 specified in JIS P3401 (2000), can be preferably used. Kraft paper No. 5 type 1 is unbleached kraft stretched paper that is given stretchability in the flow direction of paper by finely shrinking the paper on a paper machine. By using the kraft stretched paper, it is possible to effectively obtain the printed matter laying paper having a relatively weak rigidity and sufficient stretch.

The kraft stretched paper as described above can be manufactured by a device called a kurpack device. The Kurupack device is a paper that is carried in between a roll and an endless rubber blanket, and while the paper is compressed by the nip bar and the rubber blanket, the pre-stretched blanket shrinks to shrink the paper. It is a facility that shrinks the animals and increases the elongation at break. As a result, the kraft paper can be sufficiently stretched. Further, by using such stretched paper, the rigidity is lowered.

In the Kurupak device, the breaking elongation of kraft paper in the vertical direction can be adjusted mainly by the ratio of the manufacturing speed on the side entering the Kurupak device to the manufacturing speed on the exit side of the Kurupak device and the pressing force by the nip bar.

The Kurupak device is usually installed in a group of dryers in a paper machine, and in the paper produced by such a paper machine, excess water is removed after the desired crepe formation. The moisture content of the wet paper at a certain position in the dryer fluctuates depending on the relationship between the paper making speed and the basis weight of the paper machine, but when installing the Kurupak device, if the moisture content of the paper to be passed is too low, the paper will stretch. It is difficult to make the paper, and if it is too high, paper breakage is likely to occur. Therefore, it is preferable to pass the wet paper between the Kurupak blanket and the Kurupak dryer cylinder in a state where the wet paper contains 20 to 45% of water. A more preferred water content is 30-45%.

If the nip pressure between the Kurupak blanket and the Kurupak dryer cylinder is too low, the contraction of the nip outlet will be small, so it is preferably 20 kN / m or more. The surface temperature of the Kurupak dryer cylinder is preferably 100 to 120 ° C. because elongation is likely to occur, and the temperature can be adjusted by controlling the vapor pressure at the inlet of the dryer cylinder.

The ratio of the manufacturing speed on the exit side of the Kurupak device to the manufacturing speed on the entry side of the Kurupak device is called a draw rate, and the ratio of making the manufacturing speed on the exit side slower than the manufacturing speed on the entry side is called a minus draw. In order to obtain a high-strength printed matter paper, it is preferable to set the minus draw range to -3% to -8% (preferably -4% to -7%).

(Pulp species, etc.)
The type of pulp constituting the printed matter sheet is not particularly limited, but it is preferable to include unbleached kraft pulp from the viewpoint of strength and the like. Further, the lower limit of the content ratio of unbleached kraft pulp in the total pulp forming the printed matter base paper is preferably 90% by mass, more preferably 99% by mass. The pulp forming the printed matter paper may be substantially only unbleached kraft pulp. By using unbleached kraft pulp in this way, high strength can be obtained.

In the printed matter paper, it is preferable to use softwood as a raw material because the fiber length is long and it is advantageous for improving the strength. The type of coniferous tree is not particularly limited, and examples thereof include Douglas fir, larch, spruce, and radiata pine, and these may be used alone or in combination of two or more. The ratio of softwood kraft pulp to the raw material pulp is preferably 50% by mass or more with respect to the total solid content weight of the raw material pulp. Further, by blending less than 50% by mass (preferably 5 to 30%) of hardwood kraft pulp having a fiber length shorter than that of the softwood pulp, it is possible to improve the texture of the lining paper. Further, unbleached softwood kraft pulp is preferably used, and as the unbleached kraft pulp, unbleached softwood kraft pulp having a copper value of 28 to 35 is preferably used at a ratio of 80% or more. Examples of raw material pulp that can be used in combination with kraft pulp include used paper pulp and mechanical pulp.

In the printed matter sheet, the dissociation freeness of pulp dissociated in accordance with JIS P8220 (1998) is preferably 400 to 700 ml, more preferably 500, as measured by the measuring method specified in JIS P8121 (1995). ~ 650 ml. By setting the dissociation freeness within the above range, the effect of the present invention can be further enhanced.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The measurement method and evaluation criteria of each measured value in Examples and Comparative Examples are as described below.
[Basis weight (g / m ² )]
Basis weight was measured according to JIS P8124 (2011).

[Clark stiffness ^(vertical) (cm ^3/100)]
Vertical Clark stiffness was measured according to JIS P8143 (2009).

[stretch(%)]
The tensile elongation at break in the longitudinal direction was measured according to JIS P8113 (2006).

[Tensile strength (vertical) (kN / m)]
The tensile strength in the vertical direction was measured according to JIS P8113 (2006).

[Tear strength (vertical) (mN)]
The tear strength in the vertical direction was measured according to JIS P8116 (2000).

[Beck smoothness (seconds)]
Beck smoothness was measured according to JIS P8119 (1998).

[Sliding angle (degrees)]
The slip angle was measured using a slip angle measuring device (manufactured by Toyo Seiki Co., Ltd.) in accordance with the tilt method described in JIS P8147 (2010).

[Curling]
A printed matter sheet having a size of 19 cm × 24 cm was placed under the condition of 38 ° C. × 80 RH% for 3 days, then settled under the condition of 23 ° C. × 50 RH% for 7 days, and then curl was measured. To measure the curl, place the paper sheet for printed matter on a flat surface, measure the height of 16 places (the height from the flat surface to the paperboard) obtained by dividing one side of the paperboard for printed matter into four equal parts with a caliper, and calculate the average value. rice field. The larger the value, the larger the curl.
(Evaluation criteria)
⊚: Curl average value is less than 1 mm 〇: Curl average value is 1 mm or more and less than 4 mm Δ: Curl average value is 4 mm or more and less than 6 mm ×: Curl average value is 6 mm or more

[Slip of printed matter]
On the surface of the printed matter paper (length 280 mm x width 410 mm), the printed newspaper (folded in four spreads: mass about 20 kg) is placed on a parallel conveyor belt made of polyurethane resin with an inclination angle of 30 degrees. When the newspaper was conveyed in a straight line distance of 10 m in the long side direction of the newspaper, and after use, the surface of the printed matter paper was visually observed and evaluated by the following judgment index.
⊚: There was no slippage, and twisting and generation of paper dust were hardly observed.
◯: There was no slippage, and twisting and generation of paper dust were slightly observed.
Δ: There was no slippage, twisting and generation of paper dust were observed, but there was no problem with continuous use.
X: Slip occurred, twisted or paper dust was generated, and continuous use was difficult.

[Handling]
On the surface of the printed matter paper (length 280 mm x width 410 mm), the printed newspaper (folded in four spreads: mass about 20 kg) is placed on a parallel conveyor belt made of polyurethane resin with an inclination angle of 30 degrees. The state during transportation when the product was transported at a linear distance of 10 m was evaluated by the following judgment index.
⊚: There was no particular problem.
◯: There was no problem in use, but there was a slight transfer noise and deformation.
Δ: Curling and meandering occurred during transportation, although the range was acceptable for use.
X: Excessive wrinkles and meandering occurred during transportation.

[Example 1]
Using unbleached kraft pulp as the raw material pulp, a paper machine equipped with a Kurupak device was used to obtain a printed matter sheet of Example 1 ^{having a basis weight of 40 g / m 2.}

[Examples 2 to 9, Comparative Examples 1 to 3]
Using the raw material pulp shown in Table 1, adjust the basis weight to the basis shown in Table 1, and adjust the ratio between the manufacturing speed on the side entering the Kurupak device and the manufacturing speed on the exit side of the Kurupak device, and the pressing force by the nip bar. Paper sheets for printed matter of Examples 2 to 9 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 except that they were appropriately changed and the degree of elongation was adjusted appropriately.

[evaluation]
For each of the obtained printed matter sheets, the basis weight, Clark stiffness (vertical), elongation (vertical), tensile strength (vertical), tear strength (vertical), Beck smoothness and slip angle were determined by the above method. It was measured and evaluated for curl generation, slippage of printed matter, and handleability. The results are shown in Table 1.

As shown in Table 1, each of the printed matter laying papers of Examples 1 to 9 has Clark stiffness and elongation within a predetermined range, and the generation of curl when used as the laying paper is suppressed. You can see that. Further, it can be seen that the printed matter sheets of Examples 1 to 9 can suppress slippage of the printed matter to be stacked and have good handleability.

The printed matter laying paper of the present invention can be suitably used as a laying paper to be laid on a plurality of printed and stacked papers such as newspaper.

Claims (4)

It is a printed matter laying paper that serves as a laying paper when stacking multiple printed papers.
Longitudinal Clark stiffness ^is, is at 8 cm 3/100 or more 45 cm ^3/100 or less,
Longitudinal elongation state, and are 8.5% less than 5% or less,
Beck smoothness is 5 seconds or more and 11 seconds or less,
Printed material laid paper slip angle in the vertical direction, characterized in der Rukoto than 35 degrees 21 degrees. The tensile strength in the vertical direction is 2.8 kN / m or more and 10 kN / m or less.
The printed matter sheet according to claim 1, wherein the tear strength in the vertical direction is 730 mN or more and 1,200 mN or less. The printed matter sheet according to claim 1 or ² , wherein the basis weight is 60 g / m 2 or more and 70 g / m ² or less. Contains unbleached kraft pulp,
The printed paper according to claim 1, claim 2 or claim 3 , wherein the content of unbleached kraft pulp in the total pulp is 90% by mass or more.