JP2000159268A - Paper cushioning material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper cushioning material which is made up by interposing granular blowing agent capable of producing gas under heating between two sheets of paper and by sealing up the ends of overlaid two sheets of paper and is convenient for transportation, putting in storage and treatment while being available for developing cushioning capacity when the material is expanded by heating. SOLUTION: A paper cushioning material 10 is in a structure wherein blowing agent 21 is interposed between two sheets of paper 11 and 11. A thermal degradation type blowing agent is desirable as the blowing agent 21 which produces gas under heating, and a nitroso compound or the like is usable, for instance, out of organic compounds. For the paper cushioning material 10, the structure may be such a one wherein two pieces of laminated sheet, each made up by laminating a sheet of paper and a thermoplastic resin film, are put together with their paper surfaces positioned face to face, the blowing agent 21 which produces gas under heating is interposed between the laminated sheets, and ends of the overlaid two pieces of laminated sheet are sealed up. Thereby, cushioning capacity can be developed when the material is expanded by heating and at the same time, the paper cushioning materials 10 can be welded together to form a formed-up body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushioning material made of paper, and more particularly, to a cushioning material made of paper in which a foaming agent which generates gas by heating is enclosed.

[0002]

2. Description of the Related Art Hitherto, expanded polystyrene (hereinafter referred to as PS) has been used in various fields because of its excellent buffering properties, heat insulating properties, sound absorbing properties and the like. Above all, it is used in a large amount as a molded molded article of, for example, a television, a video, a food tray and the like, and a loose cushioning material.

However, PS lacks recyclability and easy processability. It is difficult to establish a collection route for recycling. The reason for this is that the low density results in a small amount of recovery by transportation, which increases the cost. In addition, there are places where a large amount of PS products can be collected, such as a fish market, as a place where they can be recycled after collection, but at present the situation is still not large.

After use, for example, when incineration is performed, high heat is generated during combustion, and damage to the incinerator is inevitable. Further, when the landfill is disposed, PS is not decomposed in the soil and remains, which causes a shortage of the landfill.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide a paper buffer material having the properties of PS beads, which can be used as a substitute for PS. Reuse without water. In other words, various applications and forms are provided with a primary expansion function and a secondary expansion function so that they can be molded using a molding machine that uses heating with a heater or pressurized steam. It is an object of the present invention to provide a cushioning material having easy transportability, easy storage and easy processing, and contributing to recycling of used paper.

[0006]

According to a first aspect of the present invention, a particulate foaming agent which generates a gas by heating is sandwiched between two sheets of paper, and the two sheets are stacked. Is a paper buffer material in which the end of the paper is sealed, characterized in that the material expands by heating to exhibit a buffer capacity.

[0007] A second invention is a particulate foaming agent which generates a gas by heating between laminated sheets in which the paper and the thermoplastic resin film layer are laminated face-to-face. Is a paper buffer material in which the ends of two stacked sheets are sealed, and the material expands by heating to exhibit a buffering capacity, and the paper buffer materials are welded to each other to form a molded body. It is a paper buffer material characterized by obtaining.

In a third aspect of the present invention, a laminated sheet in which paper and a thermoplastic resin film layer mixed with microcapsules having a diameter of 5 μm to 300 μm, which expands several tens times in volume, are laminated, face to face. A paper cushioning material in which a particulate foaming material that generates gas by heating is sandwiched between the laminated sheets and the ends of the two laminated sheets are sealed, and the material is heated. Expands to exhibit buffering capacity, and the microcapsules mixed in the thermoplastic resin layer expand while covering the thermoplastic resin, improving the adhesive strength between the paper buffer materials, and forming a hollow structure with itself. A paper cushioning material characterized in that it is possible to obtain a molded article.

A fourth invention provides a method according to the first, second or third aspect.
In the invention of the above, the foaming starting temperature of the foaming agent, the softening temperature of the thermoplastic resin film and the expansion starting temperature of the microcapsules are higher than 50 ° C and lower than 200 ° C. It is a buffer material.

[0010]

According to the present invention, as described above, a particulate foaming agent that generates gas by heating is sandwiched between two sheets of paper, and the ends of the two stacked sheets are sealed. As a result, the material expands and the buffering ability is developed.

[0011] Further, the paper sheet and the thermoplastic resin film layer are laminated on each other with the sheet surfaces facing each other,
Between the laminated sheets, a particulate foaming agent that generates a gas by heating is sandwiched, and the ends of the two laminated sheets are sealed, so that the material expands by heating and exhibits a buffering ability, The paper buffer materials are welded to each other to obtain a molded body having a buffering ability.

Further, a laminated sheet in which paper and a thermoplastic resin film layer mixed with microcapsules having a diameter of 5 μm to 300 μm, whose volume expands several tens times, is laminated with the paper surfaces facing each other. A paper foam material that sandwiches a particulate foam material that generates gas by heating between the laminated sheets and seals the ends of the two laminated sheets stacked together. In addition to developing, the microcapsules mixed in the thermoplastic resin layer expand while covering the thermoplastic resin, improve the adhesive strength between the buffer materials made of paper, and obtain a molded body that itself becomes a hollow structure Can be.

Further, the foaming start temperature of the foaming agent, the softening temperature of the thermoplastic resin film, and the expansion start temperature of the microcapsules are set at a temperature higher than 50 ° C. and lower than 200 ° C. Can be obtained in which the surfaces are strongly adhered to each other.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. FIG. 1 is a schematic explanatory view showing a cross section of one embodiment of a paper cushioning material 10 of the present invention.
It has a basic configuration in which a foaming agent 21 is interposed therebetween and sealed.

The paper 11 used has a basis weight of 30 to 150 g.
/ M ² pure white roll, Western paper such as high quality paper, 80-3
Paperboard and Japanese paper such as uncoated balls and uncoated manila of about 00 g / m ² , and those containing recycled papers thereof can be used. When the grammage is 30 g / m ² or less, even when the foaming agent is foamed to deform the paper, the stiffness of the paper is weakened and the buffering effect is weakened, and the grammage is 300 g / m 2.
^{If it is 2} or more, even if the foaming agent is foamed by heating, the stiffness of the paper is strong, the material is hardly deformed, the buffer effect is weakened, and the price is high. Although the shape and size of the material are arbitrary, the design may be made in consideration of the thickness and spreadability of the paper so that the paper material is not broken by the generation of gas.

As the foaming agent 21 that generates a gas upon heating, a pyrolytic foaming agent can be preferably used, and in the case of an organic compound, for example, an azo compound, a nitroso compound, a hydrazine derivative, a semicarbazide compound, an azide compound, a triazole compound, etc. are used. In the case of inorganic compounds, bicarbonates and carbonates, nitrites and hydroxides, and the like can be used.

Regardless of the means for sealing the ends of the two sheets of paper 11, 11, they may be simply folded or sealed with glue or the like.

A thermoplastic resin layer 12 is formed on one side of the paper 11.
Are laminated, the paper of the laminated sheet is faced to each other, a particulate foaming agent 21 that generates gas by heating is enclosed therein, and the material expands by heating and exhibits a buffering ability. A paper cushioning material 20 may be prepared, and the paper cushioning materials may be combined with each other to form a molded body 30 (see FIGS. 2 and 5). By providing the thermoplastic resin layer, the gas barrier property is improved, and the buffer material once expanded does not easily become dented.

For example, when a paper buffer material having a size of 3 cm × 3 cm is filled in a mold of 100 cm × 100 cm × 40 cm and heated, each paper buffer material is expanded by a gas of a foaming agent, and furthermore, the resin of the surface layer is expanded. The layers melt and the resin layers adhere to each other. After cooling, the resin layer is solidified and then taken out to obtain a molded product of 100 cm × 100 cm × 40 cm.

The thermoplastic resin used is 50 ° C.
It is not limited as long as it is a resin showing plasticity by heating at 200 ° C., but as an example, a low-density polyethylene resin,
Polyolefin resin represented by medium density polyethylene resin, high density polyethylene resin, polypropylene, etc.,
Polyester resins, polyacrylates, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, acrylic resins, polyvinylidene chloride, polyamide resins such as nylon, polyvinylpyrrolidone, and copolymers thereof, for example, ethylene-propylene copolymer Products, vinyl acetate-polyethylene copolymers, polyethylene-acrylic acid copolymers, etc., ethylene-α-olefin copolymers, and graft-modified or saponified products of these resins with acids, and ethylene-based resins. Wax, ethylene-butadiene-rubber resin, etc. can also be used favorably. It also includes biodegradable resins. These resins may be used alone or as a mixture. This thermoplastic resin causes adhesion between materials by heating during molding.

The means for laminating the paper and the thermoplastic resin layer is not particularly limited, and known methods such as an extrusion lamination method and a wet lamination method can be used.

Further, a laminated sheet in which a thermoplastic resin layer 13 mixed with microcapsules 31 having a diameter of 5 μm to 300 μm whose volume expands several tens times by heating on one side of the paper 11 is prepared, and the laminated sheet is formed. When the paper is faced to each other, and a particulate foaming agent 21 that generates a gas by heating is put therein, and the paper buffer material 40 in which the end surface of the laminated sheet is sealed is produced, the adhesive strength between the paper buffer materials and Buffer material with further improved cushioning performance and molded body 50 thereof
Can be produced.

As the microcapsules 31, use can be made of heat-expandable microcapsules in which a low-boiling solvent is encapsulated. That is, the polymer in the outer shell is softened by heating, the enclosed solvent is gasified, and the volume expands several tens times. Examples of the solvent to be encapsulated include organic solvents such as isobutane, pentane, petroleum ether, and hexane.

The outer shell polymer constituting the microcapsules can be exemplified by a thermoplastic resin comprising vinylidene chloride, acrylonitrile, acrylate, methacrylate, and the like. A heat-expandable microcapsule in which the above organic solvent is wrapped with a thermoplastic resin and the solvent is sealed can be preferably used.

The paper buffer material having this structure is, for example, 10
When filled in a mold having a size of 0 cm × 100 cm × 40 cm and heated, each of the buffer materials expands by the gas of the foaming agent, and further, the resin layer on the surface layer of the material melts and the buffer materials adhere to each other. The microcapsules in which the voids between the paper buffer materials are expanded fill the resin layer. After cooling, the resin layer was solidified and then taken out to obtain 100 cm × 100 cm × 40
cm of a compact is obtained.

In the step of the obtained molded body, first, the buffer material 40 made of paper is expanded by the foaming gas. This is also called primary expansion. Thereafter, the microcapsules 31 mixed in the resin layer 13 expand. This is what is called secondary expansion, and their intended purpose is different.

First, primary expansion is a large expansion like PS beads, and this material is present without bulk during storage or transportation before use, and the cost of storage and transportation is greatly reduced. Can be.

In the secondary expansion, the gap between the materials is filled by the expansion of the microcapsules covered with the resin layer, so that the adhesive strength between the materials is greatly improved. Furthermore, since the microcapsules that have expanded several tens of times are hollow structures, the buffering capacity of the microcapsules themselves is added, so that a significant improvement in the buffering capacity of the molded article can be obtained. In the present invention, a material capable of forming a shock absorber having extremely excellent shock absorbing ability has been developed.

As a result of studying the structure of the paper cushioning material,
The material used must have a foaming start temperature of more than 50 ° C, which generates the gas to be enclosed, which is a necessary condition to prevent expansion during storage and transportation when the material is not used. Was considered.

After the primary expansion, the softening temperature of the resin provided on the surface of the paper is set to be equal to or lower than the foaming start temperature of the foaming agent so that the cushioning material is bonded. If it is too far away, it expands well and does not adhere, so the temperature difference is preferably in the range of 0 ° C to 20 ° C.

If the expansion start temperature of the microcapsules is not set higher than the softening temperature of the resin layer, when the microcapsules expand when the resin layer does not melt, the expansion may not be successful with the thermoplastic resin layer covered. all right. The temperature difference is preferably in the range of 0 ° C to 20 ° C. If the expansion start temperature of the microcapsules is not lower than 200 ° C., the energy required at the time of molding increases, and there is no merit in cost.

[0032]

EXAMPLES Examples of the present invention will be described below in more detail. <Example 1> A coated ball having a basis weight of 310 g / m ² was used as the paper 11, and was stacked on two sheets, followed by 2 cm × 2 cm.
The sheet was cut into corners, and 1 microgram of Cell Micro 266 (trade name; manufactured by Sankyo Kasei Co., Ltd., foaming start temperature: 130 ° C.), which is 1 g of the inorganic compound-based foaming agent 21, was inserted between the edges. The edge was folded and sealed to produce a paper cushioning material 10 before foaming.

Then, the buffer material was placed in a drying oven at 140 ° C. for 1 minute to foam, and the paper buffer material 1 of Example 1 was foamed.
0 (see FIG. 4).

Example 2 First, a paper 11 having a basis weight of 8
1.4 g / m ² high-quality paper is used, and a 20 μm-thick opalescent polyethylene film as the thermoplastic resin layer 12 is laminated by extrusion lamination to form a laminated sheet.

Two sheets of the laminated sheet are stacked face-to-face, cut into 2 cm × 2 cm squares as in Example 1, and 1 g of Cell Micro 266, which is an inorganic compound-based foaming agent 21, is put in between. The edges of the two laminated sheets were folded and sealed to produce a paper cushioning material 20 before foaming (see FIG. 2).

Then, the buffer material was placed in a drying oven at 140 ° C. for 1 minute to foam, and the paper buffer material 1 of Example 2 was foamed.
0 (see FIG. 4).

This paper cushioning material 10 is 100 cm × 1
Fill into a 00 cm × 40 cm mold and at 140 ° C.
When heated for 20 seconds, each buffer material 10 made of paper is expanded by the gas of the foaming agent, and further the thermoplastic resin layer is melted and the resin layers adhere to each other. Thereafter, when the resin layer is cooled and the resin layer is solidified and taken out, a molded body 30 of 100 cm × 100 cm × 40 cm is obtained (see FIG. 5).

<Example 3> As the paper 11, a basis weight of 310 g
/ M ² of a coated ball, into which 5% of microcapsule 31 EXPANCEL 054 (trade name; manufactured by Sankyo Kasei Co., Ltd., expansion start temperature: 140 ° C.) is mixed. A milky white polyethylene film having a thickness of 30 μm is laminated by a wet lamination method to form a laminated sheet.

Two sheets of this laminated sheet are stacked face-to-face, cut into 2 cm × 2 cm squares as in Example 1, and 1 g of Cell Micro 266, which is an inorganic compound-based foaming agent 21, is put between them. Then, the edges of the two laminated sheets were folded and sealed to produce a paper cushioning material 40 before foaming (see FIG. 3).

This paper cushioning material 40 is 100 cm × 1
Fill into a 00cm x 100cm mold and at 140 ° C,
When heated for 120 seconds, each of the buffer materials 40 expands (primary expansion) with the gas of the foaming agent, and
The thermoplastic resin layer 13 of the surface layer of No. 0 melts and the buffer materials 40 adhere to each other. The microcapsules 31 in which the voids between the buffer materials are expanded fill the resin layer 13 (secondary expansion). 100cm x 100
A molded body 50 cm × 100 cm is obtained (see FIG. 6).

Comparative Example 1 A coated ball having a basis weight of 310 g / m ² was cut into a 2 cm × 2 cm square to obtain a paper cushioning material of Comparative Example 1.

<Comparative Example 2> A molded article was produced using the paper buffer material of Example 2 using the mold of Example 3 and used as a buffer material of Comparative Example 2 (detailed description is omitted).

COMPARATIVE EXAMPLE 3 One side of a coated ball having a basis weight of 310 g / m ² was coated with EXPAND
A 30 μm-thick opalescent polyethylene film mixed with 5% of EL-092 (trade name; manufactured by Sankyo Chemical Co., Ltd., expansion start temperature: 190 ° C.) is laminated by a wet lamination method to form a laminated sheet.

Two sheets of this laminated sheet are stacked face-to-face, cut into 2 cm × 2 cm squares as in Example 1, and 1 g of Cell Micro 496 (trade name; inorganic compound-based foaming agent) is interposed therebetween. A foaming start temperature: 180 ° C., manufactured by Sankyo Chemical Co., Ltd.) is put in, and the edges of the two laminated sheets are folded back to seal the paper, thereby forming a paper cushioning material before foaming.

This paper buffer material was used in the same manner as in Example 3 for 10 times.
Fill a mold of 0cm x 100cm x 100cm,
When heated at 0 ° C. for 120 seconds, each of the buffer materials expands with the gas of the foaming agent (primary expansion), and the thermoplastic resin layer on the surface layer of the buffer material melts and the foamable materials adhere to each other. The microcapsules in which the voids between the buffer materials are expanded fill the resin layer together (secondary expansion). 100cm x 100cm x 100c when removed from the mold after cooling
m of Comparative Example 3 are obtained.

The density, elasticity and buffering effect of the three types of paper cushioning materials thus produced, three examples and three comparative examples, were tested and evaluated by the following methods. Table 1 shows the results.

Density: 100% for Example 1 and Comparative Example 1.
A buffer material is put into a 0 ml measuring flask and measured from the weight. In Examples 2 and 3 and Comparative Examples 2 and 3, the density of the compact was measured from the volume and weight. Elasticity: The material is crushed with a finger, and the elasticity of the material is judged by feeling. Buffer effect: 20 cm × for Example 1 and Comparative Example 1.
Spread paper cushioning material in a 20cm x 15cm paper box,
The portable audio equipment was stored and dropped horizontally on a concrete floor from a height of 50 cm. For Example 2, 20 cm × 20 c
The inside of the m × 15 cm molded body was cut out, the camera was stored in the space, and the camera was dropped horizontally on a concrete floor from a height of 50 cm. 100 cm × 100 for Example 3 and Comparative Examples 2 and 3.
The inside of a molded body of cm × 100 cm was cut out, a notebook computer was stored in the space, and the notebook computer was dropped horizontally on a concrete floor from a height of 50 cm.

[0048]

[Table 1]

Considering from Table 1, first, the ability as a bulk buffer material was carried out in Example 1 and Comparative Example 1. As a result, in the drop test, the outer paper box was damaged at the corner, but the loose cushioning material was not damaged, and the portable audio equipment was not damaged. The loose cushioning material in Example 1 and Comparative Example 1 was not bulky at the time of transportation, and the storage cost and the transportation cost were almost the same. However, when the portable audio equipment was inserted, the material of Comparative Example 1 was used. Was damaged due to insufficient buffer capacity. And the weight was heavy. In the case of Example 1, the number of materials required to prevent breakage was small, so that the total weight was light and the buffering capacity was sufficient.

The performance as a molded body was performed in Examples 2 and 3 and Comparative Examples 2 and 3. In Example 2, in the drop test, neither the camera nor the buffer material was damaged. Also in Example 3, there was no damage to the computer in the drop test, and no damage to the buffer material. In Comparative Example 2,
There were no breaks in the computer, but there was delamination between the cushioning materials. In Comparative Example 3, a material in which the foaming temperature of the foaming agent added to the paper material was set higher than the melting temperature of the resin provided on the surface layer of the buffer material was placed in the mold of Example 4, and heated to obtain a molded article. However, the resin provided on the surface layer between the buffer materials flowed, and thereafter, the adhesion between the buffer materials did not work well.

[0051]

According to the present invention, the paper cushioning material of the present invention can be stored and transported densely before use, and the cost of storage and transport can be greatly reduced. Also, since recycled paper can be used, it has excellent recyclability, can be incinerated, and is easy to process. further,
When a resin layer in which microcapsules are mixed is provided, the structure can be appropriately selected according to the required buffer performance, such as further improvement in strength and buffer performance. .

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of a paper cushioning material of the present invention.

FIG. 2 is a schematic explanatory view showing another embodiment of the paper cushioning material of the present invention.

FIG. 3 is a schematic explanatory view showing still another embodiment of the paper cushioning material of the present invention.

FIG. 4 is a schematic explanatory view showing an example of a use state of the paper cushioning material of the present invention.

FIG. 5 is another schematic explanatory view showing an example of a use state of the paper buffer material of the present invention.

FIG. 6 is still another schematic explanatory view showing an example of a use state of the paper cushioning material of the present invention.

[Explanation of symbols]

 10, 20, 40 {paper buffer material 11} paper 12, 13 {thermoplastic resin layer 21} foaming agent 30, 50} molded object 31> microcapsule

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Koji Sakairi, Inventor F-term (reference), 1-5-1, Taito, Taito-ku, Tokyo 3E066 AA21 CA01 CA03 CB03 DA01 KA08

Claims (4)

[Claims] 1. A paper buffer material in which a particulate foaming agent which generates gas by heating is sandwiched between two sheets of paper, and the ends of two stacked sheets of paper are sealed. Is a paper cushioning material characterized in that it expands to exhibit a buffering capacity. 2. A laminated sheet in which paper and a thermoplastic resin film layer are laminated, with the paper surfaces facing each other, and a particulate foaming agent that generates gas by heating is sandwiched between the laminated sheets. A paper cushion material in which the ends of the two laminated sheets are sealed, wherein the material expands by heating to exhibit a buffering ability, and the paper buffer materials are welded to each other to obtain a molded article. Paper buffer material. 3. A paper having a diameter of 5 μm which expands several tens times in volume.
Laminated sheets laminated with a thermoplastic resin film layer mixed with microcapsules of ~ 300 μm are stacked face-to-face with each other, and between the laminated sheets, a particulate foam material that generates gas by heating is formed. 2 sandwiched
A buffer material made of paper in which the edges of two laminated sheets are sealed, and the material expands when heated to exhibit a buffering capacity, and the microcapsules mixed in the thermoplastic resin layer expand while covering the thermoplastic resin. A paper cushioning material characterized in that the adhesive strength between paper cushioning materials is improved, and that a molded article that itself becomes a hollow structure can be obtained. 4. The foaming agent according to claim 1, wherein the foaming start temperature, the softening temperature of the thermoplastic resin film and the expansion start temperature of the microcapsules are higher than 50 ° C. and lower than 200 ° C. Item 4. A paper buffer material according to Item 1, 2 or 3.