JPS633945A - Closed cell projection sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a plastic sheet having a plurality of independent bubble protrusions formed on its surface, and more particularly, the present invention relates to a plastic sheet having a plurality of independent bubble protrusions formed on its surface, and more specifically, the bubble protrusions are robust and resistant to bursting. Various cushioning core materials with excellent gas impermeability.

This invention relates to a closed cell projection sheet that can be applied to packaging materials, etc.

(Prior Art) When transporting items such as valuables that should not be damaged, it has been conventional practice to package these items using sheets in which a large number of closed cell protrusions are formed.

Such a sheet consists of one smooth film made of a plastic material such as polystyrene or polyethylene, and a film made of a plastic material with many small depressions formed on the surface. The surface other than the recess is heat-sealed.

By doing this, when looking at the entire sheet, depressions are formed as protrusions on the surface, and gas (
air) will be enclosed.

Therefore, the applied external force is alleviated by the elastic force of the gas within the protrusions, and the sheet functions as a cushioning material.

(Problems to be Solved by the Invention) However, the conventionally known sheets of this type are composed of plastic materials such as polystyrene and polyethylene, and their mechanical strength is not very high. When a large external force is applied, the above-mentioned protrusions are likely to be crushed or burst and lose their function as a cushioning material.

In order to solve this problem, the plastic material constituting the sheet should be made of a material with high mechanical strength, such as polyamide resin. However, plastic materials such as those described above are generally difficult to self-fuse, and thermal fusing does not proceed sufficiently. As a result, complete airtightness is not maintained at the heat-sealed portions between the films, and the gas sealed in the protrusions leaks, which also tends to cause the cushioning material to lose its function.

In addition, one side of a polyethylene sheet that is easy to self-fuse, for example, may be coated with a resin having excellent gas impermeability, such as polyvinylidene chloride, to increase the gas impermeability of the entire sheet. However, this is not practical because the gas-impermeable resin coating wears out and peels off during use, causing the gas-impermeability to disappear.

The present invention aims to solve the above-mentioned problems and provide a novel protrusion sheet whose protrusions have high mechanical strength and excellent gas impermeability.

(Means and effects for solving the problem) The closed cell projection sheet of the present invention has a smooth first laminate sheet formed by integrally laminating a plurality of plastic films, and on one side thereof,
A second laminate sheet is formed by integrally laminating a plurality of plastic films and forming a plurality of independent depressions on the surface thereof, and the surface facing the depressions is adhered to the second laminate sheet. do.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The sheet of the present invention will be explained in more detail below based on the drawings showing one embodiment of the sheet.

FIG. 1 is a partially cutaway perspective view of the sheet of the present invention, and FIG. 2 is a sectional view showing the state near the protrusion.

In the figure, 1 is a smooth first laminate sheet,
Multiple sheets of plastic film la.

It is constructed by integrally stacking lbs. FIG. 2 illustrates the case of two sheets.

2 is a second laminate sheet, which is made by laminating a plurality of plastic films in the same way as the first laminate sheet. For example, in the case of FIG. 2, two plastic films 2a and 2b are laminated. Although it is composed of integral layers,
A plurality of mutually independent recesses 2C are formed on the surface of this sheet.

The surfaces of the first laminate sheet 1 and the second laminate sheet 2 on the depression side are bonded to each other via an adhesive 3. In this manner, the protrusions 4 are formed by standing the depressions erected on the surface of the entire sheet in a state in which gas is enclosed.

Moreover, FIG. 3 illustrates a case where each laminate sheet is made by integrally laminating three plastic films.

The first laminate sheet and the second laminate sheet are sheets formed by laminating two or more sheets of various plastic films. In this case, it is preferable that at least one of the plastic films used has excellent gas impermeability.

Examples of plastic films include polyamide resin films and high-density polyethylene resin films9.
Suitable examples include linear low density polyethylene resin films, polyvinyl chloride resin films, polyvinylidene chloride resin films, and ethylene vinyl acetate saponified resin films. These films are 2
A suitable combination of two or more sheets may be used. The mechanical strength of the resulting laminate sheet is thus improved compared to that of the individual films that constitute the sheet as a whole.

At the time of this combination, the first. It is preferable that the surfaces of the second laminate sheets to be adhered to each other be made of the same type of plastic film, since this improves the adhesion effect.

The adhesive to be used may be any adhesive that can airtightly and firmly bond both sheets together; for example, acrylic pressure-sensitive adhesive, 6-nylon dissolved in alcohol together with calcium chloride, etc. , polyamide resin acid adhesives obtained by the reaction of dimer acid and ethylenediamine, thermoplastic resin adhesives such as those obtained by copolymerizing vinyl chloride and vinylidene chloride, and Araldite (trade name) made of epoxy resins. Olivaline MSR (product name) made of thermosetting resin adhesive and nitrile rubber
Rubber adhesives such as

The sheet of the present invention can be manufactured, for example, in the following manner.

First, the first laminate sheet and the second laminate sheet before forming the recess.
The laminate sheet can be formed by, for example, an inflation molding method using a commonly used multilayer die or a laminate molding method.

After that, the sheet to be made into the second laminate sheet is passed through a heating roll to soften it, and then wound around a suction drum for forming recesses while reducing the pressure inside the drum to form recesses.
Then, an adhesive is applied to the surface of the sheet using an adhesive application roll, and the first laminate sheet is roll-pressed thereon using a pressing roll to produce the protrusion sheet of the present invention.

(Example) A high-density polyethylene resin film with a thickness of 0.04 mm and a polyvinylidene chloride resin film with a thickness of 0.01 m+m were integrally laminated by a laminate molding method to produce 2
A laminate of layers was made into a sheet. This is used as a first laminate sheet. The tensile strength of this sheet is approximately 250 kg/c
i+2. Air permeability is 6.0cc/m*24br
It was e-atm.

Using high-density polyethylene resin and ethylene vinyl acetate resin, it is an inflation molding method using a two-layer die, with the former resin film having a thickness of 0.08 mm and the latter resin film having a thickness of 0.02 mm. A laminate sheet was molded.

The tensile strength of this sheet is approximately 250 kg/crs”
.

Air permeability is 3.0cc/m” * 24hre a
It was tm.

By applying the conventional concave molding method to this sheet, a diameter of 10 m was formed regularly on the entire surface of the ethylene vinyl acetate cured resin film side.
m, and a depression with a depth of 5 mm was formed. This is used as a second laminate sheet.

Next, a rubber adhesive (trade name, Olivarin MSR) was applied to the surface of the second laminate sheet other than the recesses to a thickness of 0.0.
The polyvinylidene chloride resin film side of the first laminate sheet was pressed against the surface of the first laminate sheet to bond the two sheets together.

The obtained sheet was sandwiched between iron plates with a surface area of about 150 cm2 (100 bubble protrusions were sandwiched between the iron plates), and then pressure was applied to the iron plates at a strain rate of 10 cm/min.
The state of collapse of the bubble protrusions and the state of leakage of enclosed air from the bubble protrusions were observed.

As a result, neither collapse nor air leakage was observed up to a pressure of 20 kg/c+i2. Until that pressure was reached, when the pressure was released, the bubble protrusions immediately returned to their original state.

In addition, a load of 7.5 kg (pressure crab 50 g/c) was placed on the iron plate.
When the state where m2) was applied continued for 3 months, the thickness loss due to air leakage in the protrusions was less than 10%.

For comparison, a similar test was conducted on a commercially available protrusion sheet (product name: Airbag #42, manufactured by Shudo Sangyo Co., Ltd.), and the result was a pressure of 2 kg/cm2 (strain of 80
%), and the thickness loss under the conditions described was about 60%.

(Effect of the invention) As is clear from the above explanation, the protrusion sheet of the present invention has the following features:
The bubble protrusions are robust and there is little air leakage from the adhesive surface or the protrusions themselves.

Therefore, even if a large external force is applied, the collapse of the bubble protrusions and the leakage of the enclosed air are significantly reduced, so that the function of the sheet as a cushioning material is improved.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of the closed cell projection sheet of the present invention, and FIG. 2 is a sectional view of the cell projection portion. Third
The figure is a partial cross-sectional view of a three-layer laminate sheet. 1 □ First laminate sheet la, lb □ Plastic film 2 □ Second laminate sheet 2 a, 2b □ Plastic film 2c - depressed recess 3 □ Adhesive 4 □ Closed cell protrusion Figure 2

Claims (1)

[Claims] A plurality of plastic films are integrally laminated on one side of a smooth first laminate sheet formed by integrally laminating a plurality of plastic films, and the surface has independent depressions. 1. A sheet with closed cell projections, characterized in that it is formed by bonding the surface of a second laminate sheet formed with a plurality of recesses on the side of the recesses.