JP4154779B2 - Multi-layer paperboard for printing punching - Google Patents

Description

【００１９】
【発明の効果】
本発明により、近年高速化している印刷・打ち抜き後の紙の排出部で紙詰まりを防止でき、更に、打ち抜きの見当制御ががし易く、即座に打ち抜き位置が直るような板紙が得られる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paperboard used for paper containers and the like. In particular, the present invention relates to a paperboard which is excellent in high-speed printing punching suitability in a paperboard which is printed in a wound state and subsequently punched to a predetermined size.
[0002]
[Prior art]
Since paperboard is usually used after being processed by printing, box making, etc., in addition to the basic characteristics of paperboard, processing suitability such as printability and boxing suitability is required. In particular, rigidity (strength of strength) is an important characteristic at the time of printing and box making so as not to cause a feed trouble at the time of stacking after punching.
It is also one of the important characteristics related to the strength against crushing of the box when filling and stacking the contents when packed in a box, and the strength against the blister of the box when packed with powder etc. . Therefore, it is desirable that the rigidity of the paperboard is as rigid as possible as long as it does not adversely affect other characteristics.
[0003]
Paperboard printing may be performed by a “print punching machine” in which the paperboard is supplied to the printing machine in a rolled-up state and punched after printing, or may be printed on a single sheet by supplying paperboard stacked in a sheet-fed state.
The present invention is intended to obtain a paperboard having excellent feedability in a “print punching machine”. In this case, the rigidity described above is an important requirement in order to prevent paper jamming.
[0004]
In recent years, the speed of printing punches has increased, and in this case, the following two points are particularly problematic.
The first problem is preventing paper jam at the paper discharge section after punching. This problem is generally solved by increasing the rigidity.
The second problem is the ease of punch registration control. The register control is as follows.
In the printing punching machine, the paperboard is supplied in a wound form, and is continuously printed while being unreeled. Subsequently, punching is performed at predetermined intervals while running the printed continuous paper. However, if the printing is performed for a long time, the printed pattern and punching are misaligned. When this deviation exceeds a certain level, the machine automatically detects and performs registration control by instantaneously increasing or decreasing the registration control drive roll.
[0005]
[Problems to be solved by the invention]
During the registration control described above, the tension applied to the paper changes instantaneously, so that it does not necessarily return to the punched position, and a large loss may occur, which is an adverse effect of speeding up.
The present invention provides a paperboard that is easy to register in a printing punching machine, immediately corrects the punching position, does not cause paper jamming, and can be operated even at a high paper speed of 150 m / min. This is the issue.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention adopts the following configuration. That is, the present invention is “in a multilayer paperboard having a layer structure of surface layer / surface layer / medium layer / back layer,
Surface layer having a basis weight of 30 to 80 g / ^{m 2,} a density 0.8~1.0g / cm ^3, the middle layer having a basis weight of 130 g / ^{m 2} or more, a density 0.6~0.7g / cm ^3, a basis weight of the backing layer 30 to 80 g / m ² , density 0.7 to 0.8 g / cm ³ , and the upper and lower layers have a total basis weight of 80 to 110 g / m ² of the surface layer and the lower layer ,
The bending elastic modulus Eb calculated by the following equation (1) from the Taber stiffness Ms according to JIS P 8125 measured in the winding traveling direction, and the tensile elastic modulus defined by the following (3) measured in the winding traveling direction. The value of Eb / Es divided by Es is 1.2 or more and 1.5 or less, the bending elastic modulus Eb is 330 to 460 kg / mm ² , and the tensile elastic modulus Es is 270 to 380 kg / mm ^2. it is a multi-layer Extract board "for printing beating characterized by.
(1) Formula: Eb = (Ms × L ² ) / (300 × I × δ)
However, the unit of Eb is kg / mm ² , I is the moment of inertia of the cross section represented by the following formula (2), and δ is 12.9 mm (L: deflection at a load length of 50 mm and an angle of 15 degrees). The unit of Taber stiffness Ms is g · cm.
(2) formula: ^{I =} Bt 3/12
Where B is the sample width 38.1 mm, and t is the sample thickness indicated in mm.
(3) Tensile elastic modulus: The tensile strength test specified in JIS P 8113 was conducted as specified for a sample with a paper width of 15 mm, and a load-elongation curve was recorded at the time of the measurement. The unit of Es, where Es is a value obtained by averaging the tensile moduli sometimes obtained, is kg / mm ² .
Further, all the samples measured in the above (1) and (3) are conditioned in an environment of 20 ° C. and a relative humidity of 65% according to JIS P 8111, and measured in the same environment.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The paperboard referred to in the present invention is a paperboard having a basis weight of 100 g / m ² or more and comprising at least three layers of a surface layer, a middle layer and a back layer. Preferably, the middle layer is composed of a plurality of layers in the structure of the surface layer, the surface lower layer, the middle layer, and the back layer, and the total is 4 layers or more and the US basis weight is 200 g / m ² or more.
The surface layer, using a virgin pulp or whiteness and strength or higher DIP (deinked waste paper pulp), the basis weight of the surface layer only 30g / m ² ~80g / m ² degree or desirable.
A pigment coating may be applied on the surface layer as necessary.
In the middle layer, a large amount of waste paper pulp is blended, and if possible, 100% waste paper pulp is desirable.
The back layer is mainly waste paper, and when the surface strength or size is required, size press coating or the like is performed. Moreover, when the whiteness of both surfaces is desired, the back layer has the same structure as the surface layer.
The surface lower layer is a layer for concealing the blackness of the middle layer, and uses a pulp having a slightly lower whiteness than the surface layer.
In general, the above layers themselves are often laminated to form a total of 5 to 11 layers.
[0009]
The flexural modulus Eb referred to in the present invention is calculated from the Taber stiffness Ms, and the value of Ms is measured according to JIS P8125 as described above. In the present invention, the winding traveling direction of 10 samples is measured. The average of the values measured for (vertical direction) is adopted.
[0010]
As described above, the tensile elastic modulus referred to in the present invention is Es, which is obtained by averaging the tensile elastic modulus calculated when the load is 0.75 kg and 1.5 kg, but is calculated when the load is 0.75 kg. The tensile modulus is the modulus of elasticity calculated as the slope of the straight line connecting the point and the origin at a load of 0.75 kg on the load-elongation curve. The tensile modulus calculated when the load is 1.5 kg is the load-elongation curve. It is the tensile modulus calculated as the slope of a straight line connecting the point and the origin at a curve load of 1.5 kg.
For each sample, the value at 0.75 kg and the value at 1.5 kg are averaged, and the value obtained by averaging the same measurement for 10 samples is Es.
[0011]
In order to achieve the object of the present invention, it is necessary to adjust Eb / Es to 1.2 or more and 1.5 or less.
If Es is too high, the above-described registration control in the operation of the “printing punch” will deteriorate. In addition, if Eb is too low, the register control that causes paper jam in the paper discharge unit after punching is deteriorated. Specifically, when the speed of the register control drive roll is increased or decreased, the change in tension is reduced. This is because the abruptly occurs and control becomes impossible as predicted by the reaction.
Therefore, Es is low and Eb needs to be high. However, if Es is low, generally Eb is low. If Es is made too low, the dimensional stability of the paper itself against environmental changes becomes poor.
Furthermore, when Eb is increased, Es is generally increased, and when Eb is too high, there is another problem that curling becomes difficult.
While balancing both, it is necessary to lower Es and increase Eb than general paperboard and not to impair other physical properties. As a result, Eb / Es is 1.2 to 1 The paperboard that is in a very narrow range of .5 has an unexpected effect that the operating efficiency of the high-speed “print punching machine” is significantly improved.
When controlling Eb / Es within the above range, it is desirable that Eb is 330 to 460 kg / mm ² and Es is 270 to 380 kg / mm ² in view of balance with other properties.
[0012]
As a specific method for producing the paperboard of the present invention, a large amount of NBKP (coniferous bleached kraft pulp) is blended in the surface layer or a large amount of paper strength enhancer is blended. In addition, there is a method such as using a pulp that has been thoroughly washed to remove fine fibers and fillers and further beaten.
In addition, lowering the density of the middle layer is one means. For example, a bulking agent or a synthetic fiber can be blended in the middle layer.
Furthermore, when making paper, it is also one means that the middle layer weakens the fiber orientation in the running direction (so-called machine direction) and the outer layers (surface layer, back layer) increase the fiber orientation in the running direction.
[0013]
When the layer structure is classified as surface layer / undersurface layer / middle layer / back layer, the following ranges are preferable as the physical property values of each layer specifically recommended in order to make Eb / Es within the scope of the present invention. .
For the surface layer, the basis weight is 30 to 80 g / m ² , more desirably 40 to 70 g / m ² , the density is 0.8 to 1.0 g / cm ³ , the tensile elastic modulus is 660 to 900 kg / mm ² , and the middle layer is The amount is 130 g / m ² or more, more preferably 230 to 300 g / m ² , the density 0.6 to 0.7 g / cm ³ , the tensile modulus 160 to 350 kg / mm ² , and the back layer has a basis weight of 30 to 80 g / m ^2. The range of m ² , density 0.7 to 0.8 g / cm ³ , and tensile modulus 390 to 500 kg / mm ² is optimal.
The surface layer is an intermediate value between the surface layer and the middle layer, and the total basis weight of the surface layer and the surface layer is preferably set to 80 to 110 g / m ² .
[0014]
【Example】
<Example 1>
The surface layer contains 50% by weight of LBKP and 50% by weight of used newspaper DIP, and pulp adjusted to Canadian standard freeness (hereinafter referred to as CSF) 350 cc is used. The density was 0.83 and the basis weight was 50 g / m ² . The front and lower layers had a DIP of 100%, a density of 0.75, and a basis weight of 40 g / m ² .
The middle layer uses CSF 200cc miscellaneous paper pulp, the basis weight is 235 g / m ^2, and the density of the middle layer is 0.67.
For the back layer, the same pulp as the middle layer was washed and classified to make CSF 400 cc, and then beaten and used as CSF 300 cc. The basis weight of the back layer was 60 g / m ² .
The above-mentioned method was used to measure the Taber stiffness Ms and the tensile elastic modulus of the above-mentioned total paper weight of 385 g / m ² and a density of 0.71, and the result of calculating Eb / Es according to the calculation method described above was 1.25. It was. The results are shown in Table 1 together with other measurements.
Further, winding of 1000 mm in width and 5000 m in length was applied to a printing punch, the operation status was observed, and registration control failure and paper jam evaluation in the paper discharge unit are shown in Table 1. These evaluations were based on the maximum speed of the punching machine that did not cause registration errors and paper jams. If the maximum speed (paper running speed: m / min) that can be operated without causing paper jams or registration defects is less than 150 m, the capability of the high-speed printing punching machine cannot be fully exhibited.
[0015]
<Example 2>
In Example 1, LBKP in the surface layer pulp was changed to NBKP, the surface layer density was changed to 0.86, and the basis weight was changed to 60 g / m ² . Also, the basis weight and 0.75 density table lower was 30 g / m ^2. Further, a paperboard was produced in the same manner as in Example 1 except that the density of the middle layer was changed to 0.64. Various measured values are shown in Table 1.
[0016]
<Comparative Example 1>
In Example 1, the ratio of NBKP / DIP was changed to 60/40, and the basis weight of the surface layer was changed to 40 g / m ² . Moreover, the front and lower layers were changed to a basis weight of 50 g / m ² . Further, 30% of the middle-layer magazine waste paper pulp was changed to corrugated waste paper, the basis weight was 247 g / m ² and the density was increased to 0.69.
As described above, a board having a stronger overall strength than that of Example 1 was manufactured. However, this paperboard had an Eb / Es value of 1.1, a registration control failure occurred, the paper jam was not good, and the suitability of the high speed punching machine was not excellent.
[0017]
<Comparative example 2>
The surface layer was the same as Example 2, and the surface layer was the same as Example 2 except that the density was reduced to 0.71. The middle layer used the magazine waste paper pulp like Example 1, and made basis weight 235g / m < ² >. However, the surfactant was blended in the middle layer by 0.3% with respect to the pulp, and the papermaking conditions were changed to greatly reduce the density to 0.58. The back layer was the same as in Example 1. This paperboard is characterized by a low density of 0.65 and very high stiffness, but a low tensile elastic modulus, but Eb / Es becomes too large at 1.6, resulting in poor registration control. However, the paper jam was not good and the suitability of the high speed punching machine was not excellent.
[0018]
[Table 1]

[0019]
【The invention's effect】
According to the present invention, it is possible to prevent a paper jam at a paper discharge section after printing and punching, which has been accelerated in recent years. Further, it is easy to perform punching registration control, and it is possible to obtain a paperboard whose punching position is immediately corrected.

Claims (1)

In the multilayer paperboard consisting of the layer structure of surface layer / front layer / lower layer / middle layer / back layer,
Surface layer having a basis weight of 30 to 80 g / ^{m 2,} a density 0.8~1.0g / cm ^3, the middle layer having a basis weight of 130 g / ^{m 2} or more, a density 0.6~0.7g / cm ^3, a basis weight of the backing layer 30 to 80 g / m ² , density 0.7 to 0.8 g / cm ³ , and the upper and lower layers have a total basis weight of 80 to 110 g / m ² of the surface layer and the lower layer ,
The bending elastic modulus Eb calculated by the following equation (1) from the Taber stiffness Ms according to JIS P 8125 measured in the winding traveling direction, and the tensile elastic modulus defined by the following (3) measured in the winding traveling direction. The value of Eb / Es divided by Es is 1.2 or more and 1.5 or less, the bending elastic modulus Eb is 330 to 460 kg / mm ² , and the tensile elastic modulus Es is 270 to 380 kg / mm ^2. multilayer Extract paperboard for printing punching characterized by.
(1) Formula: Eb = (Ms × L ² ) / (300 × I × δ)
However, the unit of Eb is kg / mm ² , I is the moment of inertia of the cross section represented by the following formula (2), and δ is 12.9 mm (L: deflection at a load length of 50 mm and an angle of 15 degrees). The unit of Taber stiffness Ms is g · cm.
(2) formula: ^{I =} Bt 3/12
Where B is the sample width 38.1 mm, and t is the sample thickness indicated in mm.
(3) Tensile elastic modulus: The tensile strength test specified in JIS P 8113 was conducted as specified for a sample with a paper width of 15 mm, and a load-elongation curve was recorded at the time of the measurement. The unit of Es, where Es is a value obtained by averaging the tensile moduli sometimes obtained, is kg / mm ² .
Further, all the samples measured in the above (1) and (3) are conditioned in an environment of 20 ° C. and a relative humidity of 65% according to JIS P 8111, and measured in the same environment.