JPH11107186A - Sheathing liner for base paper for corrugated cardboard, and production of paper stock for its surface layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheathing liner for base paper for corrugated cardboard, having a strength which makes it suitable as the one for base paper for high- quality corrugated cardboard and low in impurity content, and also to provide a method for producing paper stock for its surface layer. SOLUTION: This paper stock for surface layer of a sheathing liner for base paper for corrugated cardboard is obtained by including pulp recovered from old paper produced by a method comprising maceration of old corrugated cardboard by a pulper 1, separation of the fibrous portion from foreign matter by screens 3 and 3a, enrichment/drying of the separated fibrous portion by a drier 4, remaceration of the treated fibrous portion by a high-speed macerator 5 to subdivide the residual foreign matter, and separation of the finely subdivided fibers from the finely subdivided foreign matter by a double nip thickener 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered exterior liner for corrugated ball base paper and a method for producing a surface material for the liner.

[0002]

2. Description of the Related Art In recent years, due to the technological innovation of waste paper pulp, the production of so-called pseudo liners containing corrugated ball waste paper, which maintains strength, has been increasing as exterior liners for corrugated ball. Conventionally, corrugated ball pulp is manufactured by the following process (see FIG. 3). That is, the corrugated ball waste paper is disintegrated with a pulp and then sieved with a rough screening screen and a fine screening screen to separate the fiber component from foreign matter (undisintegrated material, dust, etc.), and to accept (fiber component). ) To the cleaner. The cleaner removes heavy foreign substances (for example, sand, iron rust, etc.) and lightweight foreign substances (for example, plastic, wax, pitch, etc.) in the fiber slurry by utilizing the specific gravity difference, and accepts (the fiber content). To the thickener. In a thickener, a pulp mud formation (filtration sedimentary layer) is formed on a rotating cylindrical wire mesh and concentrated and dewatered.

[0003] The freeness of corrugated ball pulp obtained by such a process is usually 400 mlc. s. below f
About 35% of fine fibers (fibers with a length of 0.5 mm or less), 190 pieces of heat eluate / about 100 g of BD, 2 pieces of white undisintegrated
It contains about%. The specific rupture, which indicates the strength level of pulp, is around 2.4, which is less than 38% of that of NUKP. As described above, the corrugated ball pulp obtained by the conventional method has low strength and contains a large amount of heat-eluting substances and white undisintegrated substances. The use for A-class, C-class liners of low grade was limited to AA,
Classified into A, B, and C grades. ).

[0004]

As described above, the corrugated paper pulp produced by the conventional method has the drawback that it has low strength and contains a large amount of heat-eluting substances and white undisintegrated substances. As an outer liner for corrugated board base paper, only a low-grade C-class liner has been used.

Accordingly, the present invention provides an exterior liner for corrugated ball base paper having a strength suitable for use as an exterior liner for high-level corrugated base paper and containing few impurities, and a surface layer thereof. An object of the present invention is to provide a method for producing a manufacturing paper charge.

[0006]

The pulp strength is determined by the strength of a single fiber and the bonding strength between fibers. The pulp is fibrillated by beating, and as the freeness decreases, the entanglement of the fibers improves, and the fiber surface is chemically activated. It is said that the strength is improved. When the liner for the exterior of the corrugated ball base paper is formed, the freeness of the surface layer is 450 ml. s. f degree,
390-410 ml for the middle layer. s. The range of f is said to be preferred. If the freeness is higher than this range, the strength decreases, and if it is low, the operability deteriorates.

The corrugated ball pulp obtained by the conventional method has a freeness of 400 mlc. s. f. Such low freeness does not mean that the entanglement of the fibers is good, and the cut ends of the fibers that do not contribute to the strength generated between the papermaking and the reprocessing of the waste paper, so-called fine fibers, are about 35%. Is also included.

Since the freeness of corrugated paper pulp by the conventional method is already close to the lower limit of the freeness suitable for the surface layer of the outer liner of the corrugated ball base paper, the freeness of the pulp during papermaking is low. It cannot be beaten further to improve the entanglement of the fibers. Therefore, in order to improve the strength of the wastepaper pulp for the exterior liner of the corrugated ball, it is important to remove as much as possible the fine fibers which deteriorate the drainage.

The hot-eluted material is mainly composed of hot-melt adhesives and gum tapes used for laminating step balls, and it is considered that hot-melt adhesives occupy a large specific gravity as thermal-eluted materials. Have been. These heat effluents are pulverized at the time of defibration with a pulp and become granular and scattered in waste paper pulp. It is desirable to remove the heat-eluted material in the form of granules as long as possible.

[0010] The heat-eluting substances in the wastepaper pulp are melted in the drying step of the paper machine and become spot-like stains, which significantly impairs the appearance of the product. Further, the white undisintegrated product is mainly used white paperboard paper that has not been disintegrated by the pulper, and causes white spots on the paper product to deteriorate the appearance quality. It is desirable to remove the white undissociated matter as much as possible, as well as the thermally eluted matter.

Since corrugated ball pulp produced by the conventional method has the above properties, it cannot be used as a surface layer of high-grade corrugated ball base paper requiring strength and appearance quality.
The present inventors have been considered to be unusable by efficiently removing excess fine fibers that cause a decrease in the strength of waste paper pulp, heat-eluting substances that reduce appearance quality, and white undisintegrated substances. The present inventors have found that it is possible to use a corrugated ball waste paper as a surface layer of a high-grade corrugated ball base paper, and completed the present invention.

That is, according to the present invention, a corrugated ball waste paper is
After fibrillation, the fiber and foreign matter are separated by a screen, the separated fiber content is concentrated and dewatered by a dehydrator, and then re-disintegrated by a high-speed disintegrator to subdivide residual foreign matter, and then to a double nip thickener. The present invention proposes a method for producing a surface layer for a liner for the exterior of a corrugated base paper, characterized by containing waste paper pulp obtained by separating fine foreign matter and fine fibers through the process.

The present invention also provides a method for separating the surface layer into fibers and foreign matter after disintegrating the corrugated ball waste paper, concentrating and dewatering the separated fiber content, re-disintegrating, and finely dividing the remaining foreign matter. The present invention proposes an outer liner for corrugated ball base paper, wherein the liner is made of a stock containing a part of waste paper pulp obtained by separating fine foreign matter and fine fibers.

[0014]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a system diagram of a Japanese-stage used paper production system, wherein the upper stage is a system diagram of the production method according to the present invention, the middle stage is a production diagram for a middle layer of an exterior liner, and the lower stage is a reject (a mixture of usable components and foreign matter). It is a system processing system diagram.

In the present invention, waste paper is first disintegrated in a pulper (low-concentration pulper) 1 by being stirred with water. Here, the hot melt adhesive and the gum
The heat-eluting material such as pulp is pulverized, becomes granular, and is scattered in the waste paper pulp.

As described above, it is desirable to remove the heat-eluted matter and the white undissociated matter while the particle size is large. Therefore, in the present invention, a plurality of types of screens are arranged immediately after the disaggregation step in the pulper 1 to perform a rough selection and a fine selection treatment, thereby removing the heat-eluted matter and the white undisintegrated matter before miniaturization.

As the screen, for example, a diameter of 2.4 is used.
mm coarsely selected screen (hole screen) 2 and a finely selected screen with different slit width (slit screen)
It is preferable to arrange 3, 3a and process in order. The screen width of the preselected screening 3 is, for example, 8 cuts (0.20 mm), and the screen width of the subsequent selected secondary screen 3a is, for example, 6 cuts (0.15 mm). The multi-stage treatment with these screens 2, 3, 3a removes about 88% of the hot eluate and about 99% of the white undissociated matter.

The atomized residual foreign matters of 0.15 mm or less which cannot be removed by the screens 2, 3, and 3a are led to a dehydrator 4 connected to a selected secondary screen 3a to temporarily remove them. After being concentrated and dewatered, it is re-dispersed by a high-speed disintegrator 5, preferably after being subjected to dust removal treatment by a heavy foreign matter cleaner 6 and a light foreign matter cleaner 7, and then subjected to a double nip thickener (hereinafter referred to as "DN thickener"). Dehydration treatment at 8). The rough screen 2 and the fine screen 3
The cleaner 9 is interposed between them.

FIG. 2 shows the structure of the DN thickener 8. In the figure, reference numeral 11 denotes a stand, on which a main roll 13 and a slave roll 14 around which a wire belt 12 is hung are supported by a shaft. ing. Numeral 15 designates the object to be processed as the main roll 13 and the wire belt 1.
A head box that blows between the two and is located inside the wire-belt 12. Reference numeral 16 denotes a screw-type discharge conveyor set in the vicinity of the slave roll 14, and one end of a cover 17 holding the scraper is a scraper 18 to serve as a scraper 18.
And is close to the nozzle 14 with a slight gap. Reference numeral 19 denotes a pan for covering the lower half of the apparatus, and 19a is a hood for covering the upper half of the apparatus. The pan 19 has a drain 20 and the hood 19a has a shower 21 for cleaning the wire belt 12.

The fiber material sent to the DN thickener 8 directly from the high-speed disintegrator 5 or through the two cleaners 6 and 7 is fed from the head box 15 to the main roll 13 and the wire belt 12. Because of the above structure, the DN thickener 8 is a normal cylindrical wire mesh thickener.
Unlike the formation of mud formation (filtration layer), only the long fibers in the waste paper pulp are selectively concentrated and dehydrated, and the fine fibers, finely divided heat-eluted matter and white undisintegrated matter are filtrated. And is efficiently removed from the system (i.e., through the wire belt 12 and the hood 19).
a, falls and accumulates in the pan 19. ).

Thus, in the method according to the present invention,
The method is characterized in that dehydration is performed once by passing through a plurality of screens 2, 3, and 3a through a dehydrator 4 and then fine particles of residual foreign matter are refined by a high-speed disintegrator 5, which is also characterized by a DN thickener.
8 is characterized in that it is removed together with the fine fibers. The waste paper pulp thus obtained has a relatively high freeness due to a low content of fine fibers, and can be beaten during papermaking to increase the strength. Then, the waste paper pulp is sent to the paper machine 23 as a part of the stock for producing the surface layer. The upper limit of the compounding ratio is usually 20%.

The following table shows the fiber length distribution and freeness after treatment at each outlet of the selected secondary screen 3a, dehydrator 4, high-speed disintegrator 5, lightweight foreign matter cleaner 7 and DN thickener 8. This shows the transition of According to this, after the treatment with the DN thickener-8, the ratio of the fine fibers of the 100 mesh pass to the whole is a very small value of 14.1%. This means that after passing through the DN thickener-8, drainage was good and freeness was high (improvement of freeness).

[0023]

[Table 1]

Actually, the freeness after passing through the DN thickener-8 was 570 mlc. s. f. 338 ml of freeness when passing through the lightweight foreign matter cleaner 7 at the preceding stage. s.
f. It can be seen from FIG. This indicates that fine foreign matter and fine fibers were sufficiently separated in the DN thickener 8 in the method according to the present invention. As a result, it can be understood that the corrugated ball waste paper which was conventionally unusable can be used for the surface layer production of the high-grade corrugated ball base paper.

By improving the freeness in this way, beating becomes possible, and as a result, a strength (specific burst) sufficiently suitable as a surface layer of the exterior liner of the corrugated ball base paper can be obtained. The following Table 2 is a strength comparison table between the waste paper pulp according to the present invention and the waste paper pulp according to the conventional method. According to the table, there is a remarkable difference between the two in the specific burst, and the effectiveness of the present invention is clear. I have. The reason why the values before and after the beating of the used paper pulp by the conventional method in the table does not change is that the conventional method cannot be beaten because of the low freeness as described above.

[0026]

[Table 2]

Separation processing step using the rough screening screen 2, the fine screening screen 3 and the fine screening screen 3a in the production line of the surface layer production paper material, and a heavy foreign substance cleaner.
The reject R containing usable fiber separated and recovered in the dust removal step by Step 6 is used for producing middle layer waste paper pulp for an exterior liner.

That is, the reject R separated and recovered
Is passed through a dehydrator 24 of a reject-type treatment system to be dehydrated, then disintegrated in a high-concentration pulper 25 and passed through a rough screening screen 26 and a fine screening screen 27 to be a cleaner.
Washed at 28. After passing through a dewatering process by a dewatering machine 29 and a beating process by a beating machine 30, it is introduced into the completed chest 31 of the middle layer production system as a part of the middle layer production stock.

In the production system for the middle layer, a part of the accept passing through the above-mentioned selected screen 3 is dehydrated by the dehydrator 33 and then guided to the completed chest 31, where the reject is beaten by the beating machine 30. The mixture is sent to the middle layer paper machine 32.

[0030]

The present invention is as described above. In the method according to the present invention, the re-disintegration step of subdividing residual contaminants by a high-speed disintegrator, which was not in the conventional process of manufacturing corrugated paper pulp in the related art And a step of separating fine fibers by a DN thickener, so that the fine fibers are largely removed. As a result, corrugated ball pulp having a high freeness is obtained, which is then further beaten in a papermaking process. Thus, there is an effect that a high-grade liner for the exterior of the corrugated ball base paper can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of manufacturing Japanese-stage waste paper including a method according to the present invention.

FIG. 2 is a configuration diagram of a DN thickener used in the present invention.

FIG. 3 is a process chart of a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulper 2 Rough screen 3 Fine screen (8 cuts) 3a Fine secondary screen (6 cuts) 4 Dehydrator 5 High-speed disintegrator 6 Heavy foreign matter cleaner 7 Light foreign matter cleaner 8 DN thickener 23 paper machine

Claims (4)

[Claims] 1. A corrugated ball waste paper is disintegrated with a pulper, then fibers and foreign matter are separated by a screen, the separated fibers are concentrated and dewatered by a dehydrator, and then re-disintegrated by a high-speed disintegrator. The method for producing a surface layer of an exterior liner for corrugated board base paper, comprising waste paper pulp obtained by finely separating residual foreign matters by a double nip thickener and then separating the fine foreign matters and fine fibers through a double nip thickener. How to make paper stock. 2. The corrugated ball according to claim 1, wherein the residual foreign matter fragmented by the re-disaggregation is supplied to the double nip thickener after being subjected to a dust removal treatment through a cleaner. A method of producing a surface material for a surface layer of a base paper exterior liner. 3. A heavy foreign matter cleaner in which the cleaner is disposed at the front stage and a light foreign matter cleaner disposed at the rear stage.
3. The method for producing a surface material for a corrugated ball base paper exterior liner according to claim 2, comprising: 4. The surface layer is obtained by defibrating waste paper from a corrugated ball, separating fibers and foreign matter, concentrating and dewatering the separated fiber, re-disaggregating to separate remaining foreign matter, A corrugated board made of a stock containing a part of waste paper pulp obtained by separating fine fibers.
Liner for exterior of base paper.