JP2001287288A - Method for manufacturing corrugated fiberboard sheet for printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable direct offset printing of a microflute corrugated fiberboard sheet. SOLUTION: A method for manufacturing an offset printing corrugated fiberboard comprises the step of collapsing flutes of the double faced microflute corrugated fiberboard sheet having a height of a flute of 1.0 mm or less and a number of flutes per 30 cm of 90 or more by a pressurizing means in a laminating unit or out of the laminating unit so that a sheet thickness at least at one edge of the sheet before printing after adhering is 0.3 to 0.8 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a corrugated cardboard sheet for printing, and in particular, to a corrugated cardboard sheet having excellent suitability for offset printing. More specifically, a packaging box for gift products, a box for food packaging such as pizza, and a corrugated cardboard sheet having improved printing workability in offset printing of a micro-flute corrugated cardboard sheet used for a paper container or the like requiring cosmetic printing. And a method for producing the same.

[0002]

2. Description of the Related Art As is well known, corrugated cardboard is a material in which a liner base paper is attached to a core having corrugated steps (flutes), and is a material used for a packaging box. Sheets made of corrugated cardboard are mainly used as container materials for the exterior of products (transportation packaging and unit packaging), as well as cushioning materials, pallets, advertising tools, core materials such as furniture and partitions, and automobiles. It is also used for ceiling materials.
By the way, the corrugated cardboard sheet is JIS standard (Z-010)
8) is divided into A, B and C stages according to the number of stages. In addition, although not specified in the standard, the E-stage is widespread. The height of the step is not a standard, but generally,
5 mm at A stage, 3 mm at B stage, 3.6 m at C stage
In the m and E stages, it is about 1.2 mm. Among them, the E-stage has the same use as a thick paperboard, and is used, for example, for gift boxes. In addition, it is sometimes laminated as a double corrugated cardboard sheet by being laminated with a material having a high corrugated height. In recent years, the number of steps is larger than E and the step height is 0.4
Corrugated boards as low as 1.0 mm have been developed and used, and are referred to as F-stage, G-stage, N-stage, mini-cardboard, micro-flute cardboard, and the like. Such micro-flute corrugated cardboard has begun to be used as a material for general paper containers, paper trays attached at four corners, and the like.

A corrugated cardboard sheet is usually manufactured by forming a single-faced corrugated cardboard at a single facer portion, and then laminating a liner base paper on the other front side at a double facer portion. Thereafter, the sheet is dried by pressing on a hot plate and then cut. Since the corrugated cardboard is a structure in which the corrugated core is sandwiched by the liner, it is lighter and more rigid than paperboard. Therefore, a paper container made of the above-mentioned micro-flute corrugated cardboard has an advantage that a lighter paper container can be obtained as compared with a paper container made of paperboard of the same rigidity. Microflute corrugated cardboard has the characteristic that the corrugation is inconspicuous, and is suitable for boxes of products that require beautiful and highly accurate surface decoration, such as gift boxes, individual boxes, and interior boxes. .

[0004] Printing on cardboard surfaces is often performed by flexographic printing presses (flexographic printer slotters).
When corrugated cardboard is used for gift wrapping, individual packaging or interior purposes, precise and beautiful printing (cosmetics) is required, so flexographic printing or gravure printing on the winding liner (both of the winding type) is performed by corrugator. It is performed by a preprinting method in which the sheets are cut one by one after they are bonded. In some cases, offset printing (sheet-fed type) or gravure printing on paper is pasted to single-sided cardboard one by one (sheet-fed bonding). Flexographic printing is suitable for relatively rough printing and multi-color printing is possible, but is not suitable for so-called full-color printing, so it is suitable for printing on cases where printing cost is to be kept low, for example, exterior cardboard boxes and the like. On the other hand, the pre-printing method and sheet-fed lamination method are printed at the liner stage, so they are more aesthetically pleasing than sheet printing, but these printing methods are more troublesome than direct printing on corrugated cardboard sheets and lack high speed. However, there is a problem that the material cost is high.

[0005]

Microflute corrugated cardboard used for gift wrapping, small packaging, individual packaging, interior decoration or as a tool material for advertisements of various varieties and small lots is required to be printed with high precision and aesthetics. It is desired that offset printing can be performed directly on the surface. However, most offset printing presses used for printing on paper containers are dedicated to paperboard, and most of them are based on single-sheet feeding (sheet feed).
It is. At present, there are no roll-off type offset printing machines in Japan. Therefore, when the microflute corrugated cardboard was printed using the above-described sheet-fed offset printing machine, as shown below, the paper feed did not go smoothly, curling occurred,
Various troubles such as irregularity when stacking paper in the paper discharge section of the printing machine have occurred.

The present inventors have studied the structure of an offset printing press in order to solve the above-mentioned trouble, and have investigated the cause of the trouble. According to the study results of the present inventors, "a phenomenon that sheets are not taken in one by one" in the sheet feeder of the printing press.
It has been found that the problem of "cannot be held by the holding claws of the printing unit" occurs because the cardboard is thick. That is, in the conventional sheet-fed offset printing press for paper containers, the allowable range of the base paper thickness is 0.3 to 0.8 mm, so that thick cardboards of A, B, and C stages cannot be used, and furthermore, It has been found that the microflute corrugated cardboard having a low corrugation height developed recently has the same problem as described above when the thickness of the entire sheet is 1 mm or more.

In the offset printing press, as shown in FIG. 1, the stacked paperboard blanks are taken out one by one from the upper surface by a vacuum soccer equipped with a suction cup, and then taken out. After that, it is transferred to the printing unit. For this reason, when looking at the printed paper, the mark on the front side of the paper is seen as a slight dent. That side is called the "mouth side". And the rear side is referred to as the “mouth butt”. The trail of the grip tells you in which direction the paper was fed to the printing press. In the above-described printing press, base paper having a sheet thickness of 1 mm or more causes poor feeding and causes trouble. The portion where the gripper grips the sheet is about 10 mm from the leading end of the sheet, and the printing pressure is applied 10 to 20 mm behind the grip (end). Therefore, it has been found that if the sheet edge portion of about 10 to 20 mm can be reduced to about 0.3 to 0.8 mm (optimally, 0.55 mm or less), trouble in feeding by an offset printing machine is reduced.

In the offset printing method, as shown in FIG. 1, after the ink is transferred to the plate surface, the ink on the plate is further transferred to a blanket cylinder called a blanket made of a soft material, and then the blanket is placed on the blanket. Is transferred to paper sandwiched between the roller and the impression cylinder. When printing on corrugated board with an offset printing machine, the printing pressure must be increased, the printing pressure must be applied to the total paper thickness of the back liner, the core, and the front liner to transfer the ink. Until the ink is applied, printing blur occurs and a washing plate-like step appears (this is noticeable with base paper having a surface liner of 140 g / m ² or less). When the printing pressure is increased, the micro flute corrugated cardboard sheet is 10 to 20 mm at the front end in the traveling direction.
Except for the edge of the sheet, the part in the vertical direction thereafter is blanketed and pressed by the blanket and impression cylinder, so to speak, the steps are crushed, thinned and curled at the same time as curling (curling) Often do.

[0009] Further, a continuously printed sheet is stacked in a sheet delivery (delivery) section of the printing press. Usually about 10
Stacked from 00 to 1500 sheets. If the edge portion is, for example, 0.2 mm thick, the height of the seat block increases from 200 to 300 mm, and the stacked sheet blocks are inclined. Therefore 500
The height must be adjusted by removing the frame or applying a padding for each sheet, which has been a problem in terms of workability and efficiency. Also, the printed microflute corrugated cardboard must be cut into a defined shape to make a paper container. Although the work is performed by a punching machine, it is very difficult to feed an inclined sheet block, and the punching register is likely to be misaligned. In addition, it is difficult to scrap off a punched sheet, which causes a problem in the entire processing process. Accordingly, the present invention proposes a method of manufacturing a corrugated cardboard sheet capable of performing offset printing directly on a sheet surface for the purpose of solving the above problems.

[0010]

A first aspect of the present invention is that a liner base paper is bonded to both sides of a stepped core base paper,
In the double-sided corrugated cardboard sheet that has been cut after lamination, after lamination, before printing, the sheet thickness near at least one edge is 0.3 mm to 0.8 mm,
A method for producing a corrugated cardboard sheet for printing, characterized in that the corrugated board is collapsed using a pressurizing means. Claim 2 of the present invention
The double-faced corrugated cardboard sheet has a corrugated height of 1.00 mm or less, 3
2. The method for producing a corrugated cardboard sheet for printing according to claim 1, wherein the corrugated cardboard sheet is a microflute double-faced corrugated cardboard having 90 or more steps per 0 cm. Claim 3 of the present invention is that, after bonding and before printing, both ends 10 in the flow direction of the double-faced corrugated cardboard sheet.
so that the thickness of the mm width is 0.3 mm to 0.8 mm,
2. The step of crushing a step using a pressurizing means.
3. A method for producing a corrugated cardboard sheet for printing according to any one of claims 1 to 2. According to a fourth aspect of the present invention, the thickness of the corrugated cardboard sheet is 0.7 to 1.1 mm, and the thickness of the crushed portion is 0.1 to 1.1 mm.
The method for producing a cardboard sheet for printing according to any one of claims 1 to 3, which is 3 to 0.55 mm. A fifth aspect of the present invention is a cardboard sheet for a paper container or an advertising tool, wherein the corrugated sheet produced by the method according to the first to fourth aspects is subjected to offset printing.

The pressurizing means for the corrugated cardboard sheet may be pressurized by upper and lower rolls, or may be arbitrarily selected according to the situation by pressurization by a lithographic press. In addition, the pressing may be performed in a process after pasting the corrugated cardboard sheet and before performing offset printing. Therefore, the pressing means may be provided in the corrugated cardboard laminating machine or provided outside the laminating machine. You may.

The portion to be crushed is a band-like region having a fixed width near the short edge of the sheet, and may be crushed on only one side as shown in FIG. 3A or on both sides as shown in FIG. . The crushing width L is preferably 10 mm or more, and crushing exceeding 20 mm is not very meaningful for the above-mentioned purpose. Further, it may be crushed in a direction parallel to the flow of the step, or may be crushed in a direction perpendicular to the flow of the machine (the running direction of the machine). In some cases, it is possible to crush the sheet before cutting the sheet on a corrugator. The thickness of the crushed part is
As described above, if it is 0.8 mm or less, it is compatible with the current offset printing machine, but in order to avoid a problem with more printing machines, it is more preferable to crush it to a thickness of 0.3 to 0.55 mm. preferable.

[0013]

According to the method of the present invention, it is possible to perform offset printing directly on corrugated cardboard by using a sheet-fed offset printing machine, and therefore, it is possible to perform precise and highly decorative printing. Further, there is no occurrence of various troubles such as a problem that the paper cannot be fed smoothly, a curl occurs, and the paper is unevenly stacked when the paper is stacked at a paper discharge unit of the printing press. By adopting this method, direct cosmetic printing can be performed with a so-called offset printing machine even with a microflute corrugated cardboard having a sheet thickness of about 1.0 mm bonded with a relatively thin base paper of about 100 g / m ² . In addition, in this specification, when referring to a micro flute cardboard,
A corrugated board having a corrugated height of 1 mm or less and 90 or more corrugations per 30 cm is assumed.

[0014]

Next, an embodiment of the present invention will be described. A preferred embodiment of the present invention is directed to a cardboard having more steps than the E step, and specifically, a step height of 1 mm.
The present invention is directed to a corrugated cardboard sheet having 90 or more steps per 30 cm, preferably a microflute cardboard having a step height of 0.55 or less and a step number of 120 or more. 0.7-1.1mm in terms of sheet thickness
Is the main object.

[0015]

[Embodiment 1] Hereinafter, the present invention will be described in detail with reference to embodiments. As a front liner / middle / back liner of a micro flute with a double-sided corrugated cardboard structure, "single-sided bleached kraft 100 g / m ² ", "double-sided bleached kraft 100 g /
m ² ”and“ both re-bleached craft 100 g / m ² ”
Laminated with a corrugator for cardboard. First, the middle core: “both re-bleached craft 100 g / m ² ” is molded with a step roll having a step height of 0.5 mm and a step number of 155 / (per 300 mm), and then a normal step mainly made of corn starch at the step top. After the paste used for the exterior cardboard is transferred by a paste roll, it is bonded to the back liner base paper “both re-bleached kraft 100 g / m ² ”. After that, after discharging to the bridge part by take-up conveyor, using a glue machine prepared separately,
After transferring the glue used for ordinary exterior corrugated cardboard mainly composed of corn starch to the top of the corrugated sheet, it is bonded to the surface liner base paper “100 g / m ^{2 of} single-glazed bleached kraft paper” and then heated to 120 ° C. to 180 ° C. using a hot plate unit. A microflute corrugated cardboard 1 having a double-faced corrugated cardboard structure is produced by heating and bonding at the surface temperature. After drying, the micro flute corrugated cardboard 1 having the thickness T ₁ shown in FIG. 2A is obtained as shown in FIG.
Upper and lower rolls 1 with roll clearance set to 0.4 mm
After crushing the width of about 10 mm at both ends of the micro flute corrugated cardboard 1 in the sheet flow direction according to 0a and 10b, the double-faced corrugated cardboard was punched into a rectangular predetermined size by a slitter and a cutter. The thickness T ₂ of the end of the post-busting was 0.5 mm. Sheet thickness T ₁ of the portion not crush treatment was 0.75 mm. further,
The part of the sheet subjected to the crushing processing was set on the grip side of the sheet feeding unit of the offset printing machine, and after printing on the front liner surface, the blank was punched into a predetermined blank size by a separately prepared punching machine. The thickness T ₃ of the sheet 2 after printing is 0.60m
m. The double-sided corrugated cardboard blanks punched by the above method had no particular problem in the required properties such as box making, despite the fact that each constituent base paper had a lower U.S.P.

[0016]

Example 2 Double-sided corrugated cardboard microflute front liner / middle core / back liner "100 g / m ² single-sided kraft", "80 g / m ² double-sided kraft",
“Both re-bleached craft 100 g / m ² ” was selected and bonded with a corrugator for cardboard. The difference from the first embodiment is that the step height during step molding is 0.6 mm, and the number of steps is 1 per 300 mm.
20. In this example, the thickness of the end of the sheet after being crushed was 0.55 mm. The sheet thickness of the portion not subjected to the crushing treatment was 0.82 mm. The crushing portion is crushed by the upper and lower rolls 10a and 10b set with a roll clearance of 0.45 mm to the width of about 10 mm at both ends in the sheet flow direction of the micro-flute corrugated cardboard 1, and set on the grip side of the sheet feeding unit. As in the first embodiment, printing was possible without any problem.

[0017]

Example 3 "Coated ball 190 g / m ² ", "Core base paper 115 g / m ² " and "Liner 160 g / m ² " were selected as the front liner / core / back liner of the microflute having a double-sided cardboard structure. Then, it was molded with a corrugator for corrugated cardboard using a corrugator with a corrugator height of 0.5 mm and a corrugation number of 155 / (per 300 mm), and bonded in the same manner as in Example 1. On the way, clearance 0.65mm by crushing roll
I crushed it. In the case of this example, the thickness of the uncrushed sheet was 0.96 mm. The crushed part is 0.7
As a result of the thickness of 5 mm, printing was possible without any problem in offset printing as in Example 1.

[0018]

[Comparative Example 1] A single-sided kraft 100 g / m ² , a double-sided kraft 80 g / m ² , respectively as a front liner / middle core / back liner of a microflute having a double-faced cardboard structure,
“Both re-bleached craft 100 g / m ² ” was selected and bonded with a corrugator for cardboard. The difference from the first embodiment is that the step height at the time of step molding is 0.6 mm and the number of steps is 120. In this case, the thickness of the sheet was 0.82 mm. In particular, since no crushing is performed, a phenomenon of “double”, which is one of the paper feeding failure and the printing failure, has occurred in offset printing.

[0019]

Comparative Example 2 "Coated ball 190 g / m ² ", "Core base paper 115 g / m ² ", and "Liner 160 g / m ² " were selected as the front liner / core / back liner of the microflute having a double-faced cardboard structure. The pieces were pasted together using a corrugator for corrugated board. No crushing was performed. In this case, the thickness of the sheet was 0.96 mm. Since the base paper, especially the base liner base paper, was relatively thick and made of paperboard, the color development was good in offset printing, but the phenomenon of feeding errors was the same as in Comparative Example 1.

The following table shows the suitability for feed in an offset printing machine and the effect of the direct printing finish performed on the examples and comparative examples of the present invention.

[0021]

[Table 1]

[0022]

By using the cardboard according to the present invention, it is possible to carry out offset printing directly on the cardboard by a sheet-fed offset printing machine, and it is possible to make the offset printing with high aesthetics on the cardboard. In addition, it is possible to improve the occurrence of various troubles such as difficulty in feeding paper, occurrence of curl, and irregularity in stacking paper at the discharge section of the printing press. According to the present invention,
Direct cosmetic printing can be performed with an offset printing machine even with a microflute corrugated cardboard having a sheet thickness of about 1.0 mm bonded with a relatively thin base paper of about 100 g / m ² .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an offset printing press.

FIG. 2A shows a state of the thickness T ₁ of the microflute corrugated cardboard 1 before being crushed, and FIG. 2B shows a state of the thickness T _{2 of the} end obtained by crushing the width of about 10 mm at both ends in the sheet flow direction. shown, (c) shows the thickness T ₃ state of the seat after the offset printing process.

FIG. 3 is a plan view in which a corrugated cardboard sheet is punched into a predetermined blank size, (a) shows a state where one side of the sheet edge is crushed with a width L, and (b) is a state where both sides of the sheet edge are crushed with a width L. FIG.

[Explanation of symbols]

 1 Micro flute corrugated cardboard before printing processing 2 Micro flute corrugated cardboard after printing processing 10a, 10b Upper and lower rolls

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Sadao Kanno 5-12-8 Ginza, Chuo-ku, Tokyo Oji Packaging F-term (reference) 3E078 AA17 BB03 BB46 BB48 CE08X DD18 4F100 BA03 BA06 BA10A BA10C DB08 DB15 DD12B DG10A DG10B DG10C EJ173 EJ263 GB16 HB31

Claims (5)

[Claims] 1. A double-faced corrugated cardboard sheet obtained by laminating liner base paper on both sides of a corrugated core base paper and cutting the sheet after laminating, wherein at least one edge near the edge after lamination and before printing A method for manufacturing a corrugated cardboard sheet for printing, characterized in that a step of crushing a step using a pressing means is performed so that the sheet thickness of the sheet becomes 0.3 mm to 0.8 mm. 2. The double-faced corrugated cardboard sheet has a corrugated height of 1.0.
2. The method for producing a corrugated cardboard sheet for printing according to claim 1, wherein the corrugated cardboard is a microflute double-faced corrugated cardboard having 0 mm or less and 90 or more steps per 30 cm. 3. After laminating and before printing, a thickness of 10 mm width at both ends in the flow direction of the double-faced corrugated cardboard sheet is 0.3 mm.
3. The method for producing a corrugated cardboard sheet for printing according to claim 1, wherein the corrugated board is crushed using a pressurizing means so that the corrugated board has a thickness of about 0.8 mm. 4. The corrugated cardboard sheet has a thickness of 0.7 to 1.1 m.
m, and the thickness of the crushed part is 0.3 to 0.55 mm
The method for producing a cardboard sheet for printing according to any one of claims 1 to 3, wherein 5. A corrugated cardboard sheet for an advertising container or an advertising tool, wherein a corrugated cardboard sheet produced by the method according to claim 1 is subjected to offset printing.