JPS60906B2 - Liner for cardboard - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liner for producing a strong ball with excellent moisture resistance, impact resistance, bending strength, tensile strength, tear strength, and puncture strength. .

Corrugated cardboard is usually made of a corrugated core with liners made of kraft paper attached to both sides, and it is well known that it is often used as a packaging material, such as in the form of boxes.

However, conventional corrugated cardboard made of a core and kraft paper can maintain sufficient mechanical strength if the surrounding area is dry, but when it gets wet or in a humid atmosphere. The material becomes soft when moisture penetrates into the middle, and a damp package cannot be wrapped in corrugated cardboard. Therefore, a corrugated board with excellent moisture resistance was required, and one solution was to laminate a cloth sheet made of thermoplastic synthetic resin on the surface of the kraft paper to provide at least one liner (attached to the core). Therefore, a product was devised in which this liner was attached to a core with the cloth sheet facing outward.
Although the above-mentioned corrugated board is highly waterproof, has no water permeability, and has excellent moisture resistance, various problems remain. That is, compared to conventional cardboard pasted with kraft paper, it has the drawbacks of lower productivity and pressure resistance, and poor cutting and printing finishes. When producing corrugated cardboard with kraft paper attached, use a corrugating machine to paste kraft paper into the core with cornstarch glue at 150 to 180 ml.
It is produced by applying heat at ℃ and pasting at a speed of 80 to 150 skins per minute.

However, in the case of using a liner in which a cloth sheet is stacked on one side of the kraft paper described above, applying high heat as described above may cause the cloth sheet to be thermally deformed and peel off, so it must be processed at a low temperature and at a reduced speed. There is a need.
However, due to the low temperature, moisture remains in inexpensive cornstarch glue, resulting in a decrease in pressure resistance. Therefore, it is manufactured by pasting it using a water-soluble synthetic resin adhesive, such as vinyl acetate resin, but because the speed is reduced and the heating temperature is low, the adhesive remains in the product and is not sturdy. becomes. In addition, when cutting, the cross sheet tends to peel off from the cut edge, resulting in poor finish at the cut end.Also, when printing, the surface of the cloth sheet is uneven, which reduces clarity and makes it difficult to use. There was also a problem. This invention takes into account the above points and develops a liner that can produce strong corrugated cardboard under conventional manufacturing conditions, and has moisture resistance, impact resistance, bending strength, tensile strength, and tear strength. In order to form a corrugated board that improves puncture strength, the corrugated paper is made of paper such as kraft paper and laminated resin is applied to the surface of the paper to facilitate adhesion to the corrugated core. A cloth sheet made of thermoplastic synthetic resin fibers that improves puncture strength through the coating layer is provided on the surface of the cloth sheet, which prevents heat dissipation during cardboard molding and stabilizes the cross sheet and laminated resin coating layer. Paper such as kraft paper, which serves as a cover for the design, is attached via a laminated resin coating layer.

Therefore, it is a 5-layer liner, which provides many effects that cannot be imagined from conventional cloth sheets in which kraft paper is laminated on only one side. Hereinafter, embodiments of the liner according to the present invention will be described in detail with reference to the drawings.The cloth sheet 1 is a plain-woven fabric made of flat yarns of polypropylene resin or polyethylene resin, and its structure is, for example, 1000 denier, with flat yarns on the middle 3 sides being 1 If you factor in 8 lines per inch, 3
×8 = 24 legs, so we used one with almost no gaps in the weave.

If it is necessary to further improve the strength, increase the number of flat yarns or increase the thickness of the flat yarn.
On the other hand, if such strength is not required, a medium-hexapod flat yarn with four threads per inch may be used. That is, the cloth sheet has a small number of openings, and it is not preferable to use a cloth sheet with openings like a net. Paper 2 and 3 such as kraft paper are layered on the front and back sides of the cloth sheet with laminated resins of the same type as the material of the cloth sheet, for example, paper 2 and 3 are layered on the cloth sheet made of polypropylene resin fibers. ,3
When laminating the sheets, the papers 2 and 3 are heated and corona treated, a polypropylene laminate resin is injected between the overlapping cross sheets and both papers 2 and 3, and the three are pressed together using a cooled roller. .

- As shown in Fig. 2, the product produced in this way has a laminated resin coating layer 4 formed between the cloth sheet 1 and both papers 2 and 3, and the coating layer 4 covers both sides of each flat yarn of the cloth sheet 1. In addition, the valleys between the warp and twill yarns are filled with a laminated resin coating layer to form a flat plate, and in reality, the cross sheet 1
, a pair of laminated resin coating layers 4, 4 and a pair of paper 2,
3, resulting in a product exhibiting 5 layers. Note that the cloth sheet 1 is not necessarily limited to flat yarn; multifilament yarn made of long fibers, monofilament yarn, or spun yarn may be used.

In addition, for example, a sheet of mixed weave may be used in which the warp is a flat yarn and the weft is a different type of yarn. Since the liner according to the present invention has the above structure, water permeability is completely sealed by the cloth sheet 1 and the laminated resin coating layer 4, resulting in a product with excellent water resistance.

In addition, the processing heat (1
Even if heat of 50 to 180 degrees is applied, the papers 2 and 3 do not peel off from the cloth sheet 1, and the cloth sheet 1 does not shrink and maintains its plate state when formed. This has been confirmed through experiments, and since the cloth sheet is fixed with paper from both sides through a coating layer, the flat yarn does not fray from the cut end, resulting in a beautiful cut. Therefore, when manufacturing corrugated board using the five-layer liner of the present invention, an attempt was made to manufacture it under the conditions of the conventional manufacturing method in which kraft paper is pasted on both sides of the core with cornstarch glue, and a corrugated core was used. After pasting one sheet of kraft paper on each core 5 with cornstarch glue, the five-layer liner of the present invention was pasted on the other side of the core 5 with cornstarch glue, and the rate of rotation was approximately 100 per minute.
When manufactured by applying heat of 16,000 ℃ at skin speed, the cross sheet in the liner of the present invention did not peel off, but on the contrary, it was protected by the paper 2 on the opposite side from the side that was bonded to the core. It has been demonstrated that the product can be manufactured in an extremely stable state without shrinkage.

Furthermore, we conducted water resistance tests, bursting strength tests, and puncture strength tests on the cardboard manufactured in this way, and the results were exactly as expected.A box was made with the side to which the liner of the present invention was pasted on the inside, and water was poured into the box. 2. Uniquely, even if you leave it for a long time, water will not seep into the inner core, and when you drain the water and dry it, the paper on the wet side will not peel off, and it can be easily sewn or nailed. However, the cardboard was of extremely good quality and did not burst. Incidentally, the shape of the packaging box is generally rectangular in many cases, and in such cases, it is preferable that the cloth sheet is woven with a larger number of threads on the short side than on the long side. As described above, the corrugated board liner according to the present invention has a paper that can be bonded with cornstarch glue on one side of a cloth sheet through a laminated resin coating layer, and a cloth sheet with a laminated resin coating layer on the other side. The sheet is laminated with a box filter paper to stabilize it.
It is able to withstand the heat of corrugated board manufacturing without shrinking or peeling, and has further increased water resistance and bursting strength over the entire surface, making it ideal as a corrugated liner. It is also widely used not only for cardboard, but also for construction materials, for example.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a liner according to the present invention in a partially peeled state, FIG. 2 is an enlarged cross-sectional view, and FIG. 3 is a cross-sectional view of a corrugated board using the liner according to the present invention. 1...Cross sheet, 2, 3...Paper, 4...Fuminate resin coating layer, 5...Center core. Figure 2 Figure 3

Claims (1)

[Claims] 1 Paper is applied to the front and back surfaces of a cross sheet made of thermoplastic synthetic resin fibers woven with almost no gaps in the apparent weave, through a laminated resin coating layer that covers the entire front and back surfaces with a resin similar to the cloth sheet material. A cardboard liner made of laminated layers.