JPH0444974A - Moisture and water absorbing corrugated packaging material - Google Patents

Abstract

PURPOSE:To avoid an easy loss of cushioning performance of a packaging material when it is wet or moistened and avoid a direct restriction of the water absorbing amount by the surface area of a liner by a method wherein a packaging material consists of at least an inner part and a liner in contact with the spaced ridges of the corrugated inner part and the inner part is formed of a fiber base material having a high water absorbing polymer fixed thereto. CONSTITUTION:A corrugated cardboard 1 consists of a liner 2 and an inner part 3 attached thereto in a corrugated form by a joining means 4 consisting an alkali starch paste. Concerning the fiber-like base material 6 having a high water absorbing polymer 5 fixed thereto for use in the inner part 3, the base material having two- or three-dimensional networks consisting of fiber 7 and the foam plastic sheet base material such as foam urethane sheet having the similar networks are available. Preferably, the base material 6 and the polymer 5 having some water absorbed therein are pressed into a one-piece structure under emboss roller to fix the polymer 5 more firmly to the fiber 7 so as to form a fiber-like material 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to packaging materials, and more particularly to packaging materials with excellent water absorption properties that utilize superabsorbent polymers.

(Prior art) Corrugated board, which is a type of packaging material, is usually made of paper by shaping a core base paper into a corrugated shape and bonding it to a liner base paper using an alkali/starch glue.
In terms of shape, it can be divided into single-sided corrugated cardboard, double-sided corrugated cardboard, multi-sided corrugated cardboard, etc. In terms of raw materials, plastic corrugated boards are also known that are obtained by extrusion molding a thermoplastic plastic instead of the base paper.

However, the above-mentioned paper cardboard generally has poor water resistance, and if it leaks into water or absorbs moisture, the paper will soften and the elasticity of the core will decrease, causing the cardboard to lose its original shape, strength, and cushioning performance. , it becomes useless as a packaging material. It has also been proposed to make cardboard using base paper mixed with activated carbon.

In this case, a large amount of water absorption cannot be expected, and it is difficult to prevent the base paper from absorbing water and softening. Although the use of plastic cardboard has no problems with water resistance, it is mostly limited to repeated use due to its cost, and its high rigidity makes it suitable for use as cardboard boxes, but paper cardboard It is unsuitable for use as a mere cushioning material, and an alternative must be provided.

(Problem to be solved by the invention) As mentioned above, paper cardboard can be used in cases where there is a high possibility of getting wet with water or absorbing moisture.An alternative cushioning material or packaging material should be provided. is preferred.

One of the techniques for providing a water-absorbing layer on a single-layer cardboard box is disclosed in JP-A No. 60-240679, which involves providing a water-gelling layer using a water-absorbing gelling agent on the inner surface of the top lid of the box. There is a problem in that the amount of agent used is limited by the inner area of the lid, and therefore the amount of water absorbed by the box is also limited by the inner area of the lid. It can be used in place of a cardboard box, and does not easily lose its cushioning performance even if it gets wet or absorbs moisture.
Moreover, the purpose of the present invention is to provide a corrugated packaging material with excellent moisture absorption and water absorption performance, whose water absorption amount is not directly limited by the surface area of the liner.

(Means for Solving the Problems) In order to achieve the above object, the gist of the present invention is that the core comprises at least a core and a liner to which the core is intermittently joined in a corrugated shape, the core is An object of the present invention is to provide a moisture-absorbent corrugated packaging material characterized by a fibrous base material to which a super-absorbent polymer is fixed.
Other important points will be clarified in the description below.

(Functions and Effects) In the present invention, a fibrous base material to which a superabsorbent polymer is fixed is used as a core, and this is intermittently joined to the liner in a corrugated shape. If the fibrous base material is joined in a corrugated shape, it becomes possible to use the fibrous base material over a wide area that is not restricted by the area of the liner, and accordingly, the amount of the superabsorbent polymer can be used without being restricted by the area. becomes possible.

The corrugated bonding itself gives the packaging material of the present invention cushioning performance, but in addition, the superabsorbent polymer absorbs moisture and water, swells and becomes a gel, and the gelled superabsorbent polymer becomes flexible. Since it is rich in cushioning properties, it contributes to further improving the cushioning performance of the packaging material of the present invention when it absorbs moisture.

5 Liners can be selected depending on the intended use of the packaging material of the present invention.Thick paper or plastic sheets with strong stiffness are suitable for making boxes, while thin paper or plastic films with weak stiffness are suitable for making boxes. , suitable for use as a packaging material with buffering properties. In addition, when joining the liner and the core, the liner and/or the core may be given heat-sealing properties in advance at least at the joint portion, and if this is heat-sealed, a water-resistant joint can be achieved. easily obtained.

(Examples) Next, the details of the present invention will be explained using examples as follows.

[Example 1] Fig. 1 is a perspective view of a single-sided corrugated board l which is an example of the packaging material according to the present invention. Cardboard I is liner 2,
It is composed of a core 3 which is joined to the liner 2 in a corrugated shape using an alkali/starch glue as a joining means 4.

2 and 3 show end faces of a fibrous base material 6 to which a superabsorbent polymer 5 is fixed, to be used as the core 3. FIG. Examples of the fibrous base material 6 include a base material having a two-dimensional or three-dimensional network structure made of fibers 7, and a foamed plastic sheet base material such as a foamed urethane sheet that also has a network structure. More specifically, preferred examples include a carded web made of fibers 7, a woven nonwoven fabric 5, and the like. Fiber 7 is short fiber,
Regardless of the long fibers, natural fibers such as rayon fibers, thermoplastic synthetic fibers such as polyethylene, polypropylene, nylon, polyester, and mixtures thereof can be used. The fibers 7 preferably include thermoplastic synthetic fibers in order to enable thermal fusion of the fiber base material 6 to the liner 2 as described below.

As the superabsorbent polymer 5, a known superabsorbent polymer can be used, but when superabsorbent polymer particles or powder are used, they are sprinkled on the fibrous base material 6. More preferably, the base material 6 and the polymer 5 are integrated under pressure with an embossing roller or the like while the polymer 5 absorbs a small amount of water, so that the polymer 5 is more firmly fixed to the fibers 7, and the polymer 5 is formed into a fibrous shape as shown in FIG. Let it be the base material 6. More preferably, such pressure-
Before incorporation, an air-permeable and water-permeable coating 8 is applied to at least one side, preferably both sides, of the base material 6 to form a fibrous base material 6 as shown in FIG. In FIG. 1, such a base material 6 is used.

Another promising method for fixing the superabsorbent polymer 5 is to coat the base material 6 with the monomer of the polymer 5 by roller coating, spray coating, etc., and then polymerize it by heating, electron beam irradiation, etc. be.

With this method, the polymer 5 is polymerized and cured so as to wrap around the fibers [7], and is extremely strongly fixed on the base material 6, so that the possibility of the polymer 5 falling off from the base material 6 can be significantly suppressed. However, even in this case, the base material 6
It is more preferable that the coating 8 be provided by a suitable bonding means such as crimping or adhesive to prevent the polymer 5 from falling off the base material 6. The covering 8 may be made of thermoplastic synthetic fibers to enable thermal fusion to the fibers 7 and the liner 2, preferably nonwoven fabric or tissue paper containing hydrophilized thermoplastic synthetic fibers.

The joining means 4 can be appropriately selected in consideration of the properties of the materials such as the liner 2, the fibrous base material 6, and the coating 8.
Preferred specific examples include bonding using alkali/starch glue, which is well known in corrugated board manufacturing, as well as true melt bonding, heat fusion bonding, and the like. As mentioned above, in order to enable the heat fusion, it is preferable that the III fiber 7 and the coating 8 contain thermoplastic synthetic fibers, and the liner 2 should be laminated with a thermoplastic synthetic resin film. I can do it.

FIG. 4 shows an example in which the single-sided corrugated board 1 shown in 1st @ is manufactured by a known corrugated board manufacturing process.

The fibrous base material 6 wound up on a roll is fed between a pair of tooth-shaped rolls 10.11, and pasted through a pasting roll 12 while being punched into a corrugated shape. The material 6 is adhered to the liner 2 under pressure to form the core 3, and the single-sided corrugated board 1 is completed.

The obtained single-sided corrugated board 1 can be used by adjusting the amount of the fibrous base material 6 used depending on the height of the corrugated core 3, and accordingly adjust the maximum water absorption amount of the single-sided corrugated board 1, and is also different from the paper corrugated board. Similarly, it can be used as a packaging material with high cushioning performance. In this case, an example of when the superabsorbent polymer 5 absorbs moisture and swells is shown by the chain [I4] in FIG. The fibrous base material 6, which is the core 3, swells in the directions of arrows A and B, and in particular, in the direction of A, there are no obstacles and the fibrous base material 6 can freely swell.

[Example 2, Figures 5A-5B, and Figure 6 show that in the fibrous base material 6,
An example will be shown in which the superabsorbent polymer 6 is unevenly distributed and fixed. FIG. 5A shows a case where the amount of fixed polymer 5 changes in the longitudinal direction of the fibrous base material 6. Area 15 is the area where the amount of polymer 5 is large; Area 16 is the area where there is no polymer 5. FIG. 5B shows a corrugated board 1 having a core 6 of FIG. This is the top of one.

FIG. 6 shows an example in which the superabsorbent polymer 5 is unevenly distributed and fixed near the outer surface of the fibrous base material 6 and used for the core 3.

In all of the present examples, the distribution density of the super absorbent polymer 5 should be varied in the core 3, but especially in the example shown in FIG. 6, the liner 1 of the core 3 2
Bor on the opposite side.

The mer 5 is distributed at a low density, and the other outer surface side 6 is distributed at a high density. In this way, polymer 5
It is possible to more effectively utilize the material economically, improve part of the moisture absorption/water absorption efficiency, and secure heat fusion between the inner core 3 and the liner 2.

C Example 3] FIG. 7 shows an example in which a water-repellent coach ink 17 is applied to a part of the outer surface of the core 3 along the line of the bond 4 to the liner 2. If the joint 4 is made by an adhesive with poor water resistance, it is preferred that such a coating 17 protects the joint 4 from water leakage.

[Embodiment 4] FIGS. 8 and 9 show an example in which the present invention is implemented as a screen cardboard 20. Such a corrugated board 20 is advantageous when making a water-absorbing corrugated box according to the present invention. The corrugated board 20 has a liner 2-21 and a core 3. For example, it is preferable that the liner 2I have air permeability and water permeability. A large number of through holes 22 in the liner 2I
An example is shown below.

[Embodiment 5] FIG. 10 shows an example in which the present invention is implemented as a double-sided corrugated board 25. Here, if the two-layer core 3.3' and the three-layer liner 2.26.27 are used in this embodiment, the strength of the corrugated board can be further improved compared to Example 4. By providing appropriate through holes (not shown) in the liner 2, 25° 27, the water absorption of the cardboard 25 can be greatly increased.

[Example 6 and Figure 11 show an example in which cores 3 and 3' are provided on both sides of the liner 2, and the liner 2 is used as a packaging material 30 with much better water absorption and cushioning performance than in Example 1. can.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a single-sided corrugated board showing an embodiment of the present invention;
FIGS. 2 and 3 are end views and oblique i! l! Figure 4 shows the outline of the manufacturing process for single-sided corrugated cardboard (1).
A. Figures 5A and 5B are a plan view of the w & cross-shaped substrate and an end view of a single-sided corrugated board showing another embodiment, and Figures 6 and 7 are an end view of a single-sided corrugated board showing another embodiment. Figure, Figure 8,
FIG. 9 is an end view and a perspective view showing an example using double-sided corrugated cardboard, and FIG. 10 is an end view showing an example using double-sided corrugated cardboard.
FIG. 11 is an end view showing still another embodiment. l... Single-sided corrugated pole (hygroscopic/water-absorbent corrugated packaging material) 2, 21.26.27...liner 3.3'...core 4...joint 5.super absorbent polymer 6.-fibrous group Material 7 Fiber
8...Coating 20...Double-sided cardboard
22...Through hole diagram diagram diagram diagram diagram diagram

Claims (6)

[Claims] (1) A moisture absorbing material comprising at least a core and a corrugated liner to which the core is intermittently joined, the core being a fibrous base material to which a superabsorbent polymer is fixed. Water absorbent corrugated packaging material. (2) The moisture absorbing material according to claim 1, wherein the core is formed by bonding a covering sheet to at least one side of the fibrous base material.
Water absorbent corrugated packaging material. (3) The moisture-absorbing corrugated packaging material according to claim 1, wherein the core and the liner are joined by thermally melting the core and/or the liner. (4) The hygroscopic/water-absorbing corrugated packaging material according to claim 1, wherein the superabsorbent polymer is unevenly distributed and fixed to the fibrous base material. (5) The moisture-absorbent corrugated packaging material according to claim 1, wherein the liner has air permeable through holes on its surface. (6) The hygroscopic/water-absorbing corrugate packaging material according to claim 1, wherein the liner has the core joined to each of both surfaces thereof.