JP2001219971A - Composite cushioning material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cushioning material which is extremely resistive against deformation caused by load while maintaining excellent cushioning capacity by a method wherein a composite material is made up by combining an air- permeable low density molded matter with another material. SOLUTION: A composite cushioning material is made up by combining an air-permeable low density molded matter with a matter (called as a matter having benignant creep characteristic) which is less liable to deform by compression than the aforementioned low density molded matter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite cushioning material exhibiting excellent characteristics against heavy objects to be buffered (wrapped goods).

[0002]

2. Description of the Related Art Styrofoam conventionally used as a cushioning material for packaging has excellent shock absorbing properties, can be easily processed into an arbitrary shape, is inexpensive, lightweight, and has a good appearance. It has the following characteristics. However, in recent years,
As interest in environmental issues has increased, there has been an increasing demand for disposability after use, as with other so-called plastic products. In other words, it has been pointed out that when incinerated after use, damage to the furnace and generation of toxic gas due to generation of high temperature are pointed out. Further, when the landfill treatment is performed, it is considered to be one of the causes of shortage of the treatment plant because it is not decomposable and is bulky.

As a solution to the problem in the processing of styrofoam, the inventors of the present invention have proposed, before the filing of the present application, that “water, which is a medium of slurry, is passed through a small hole of a mold having a large number of small holes on a wall surface. Removing the porosity impervious component of the slurry into the mold by removing the slurry, forming a wet molded article using the slurry having a Canadian Standard Freeness (CSF) of 550 ml or more; Then, a method for producing a molded article obtained by drying the molded article in or out of the mold "and a pulp-based low-density molded article obtained by the wet method and having excellent thickness and cushioning property (trade name: Green Pal: manufactured by Oji) Various proposals have been made.

[0004]

However, the low-density molded article having a high air permeability obtained by depositing fine components such as pulp like the above-mentioned low-density molded article has a comparative advantage in terms of an object to be buffered (a product to be wrapped). If it is light and lightweight, it can exhibit excellent cushioning properties and be an excellent packaging material.
If is a heavy object, because the deformation of the molded body gradually progresses with the passage of time due to the load, when the packaged goods are stored in several stacked layers, so-called stacked storage, There is a problem that the cargo may fall down. SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite cushioning material of a gas-permeable low-density molding system having excellent cushioning properties and having less deformation even when a heavy material is used as a material to be buffered.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the present situation, and as a result, have maintained excellent cushioning properties by combining a gas permeable low density molded body with other materials to form a composite. As it was, they found that it was possible to improve the cushioning material with extremely little deformation under load, and completed the present invention. That is, the present invention is a breathable low-density molded article,
A composite cushioning material characterized by combining an object whose compression deformation is smaller than that of the low-density compact (referred to as an object having good creep characteristics). Among them, the air-permeable low-density molded body supplies slurry into a mold having a large number of small holes on a wall surface,
By removing water, which is a medium of the slurry, from the small holes, the small components that did not pass through the small holes in the slurry were deposited in a mold to form a wet molded product, and then subjected to a drying treatment. Preferably, it is In particular, the composition of the slurry used for producing the air-permeable low-density molded product has a Canadian Standard Freeness (CSF) of 550 ml or more.
It is preferable to have In the present invention, it is preferable that the air-permeable low-density molded article has a portion of a deposited layer having a thickness of 10 mm or more. In addition, a fiber is preferable as a main raw material of the air permeable low density molded body. Among them, natural organic polymer fibers are preferable, and particularly, cellulosic fibers are preferable. In the present invention, it is preferable that the good creep property object is a composite cushioning material incorporated in a portion of the deposited layer having a thickness of 10 mm or more of the air permeable low density molded body. Further, in the present invention, the good creep characteristic object is 0.1 kg / cm ²
It is preferable that the object has a compression deformation of 5% or less after a lapse of 100 hours under the above load. In particular, it is preferable that the good creep property object is made of a natural material. Further, it is preferable that the good creep property object is made of fiber as a raw material. Further, the good creep property object is preferably a paper tube, corrugated cardboard, laminated corrugated cardboard, paper honeycomb structure, waste paper board, fiber board, particle board, or wood.

The cause of the success of the present invention is that the air-permeable low-density molded article is not used alone as a cushioning material, but is combined with another material which is less deformable under load, thereby impairing the cushioning characteristics. In other words, the present invention has found that a molded article having very little deformation can be obtained even when a heavy object is used as a buffered object.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the air-permeable low-density molded article used in the composite cushioning material of the present invention, a low-density molded article formed by a dry process, for example, a cell mold (made by Rengo) can be mentioned. A low-density molded product obtained by a wet molding method is preferable in that a stable product having little variation in quality is easily obtained. Further, as a low-density molded body, one having a location of a deposited layer having a thickness of 10 mm or more is more preferable because it exhibits extremely good buffer characteristics.

Hereinafter, a low-density molded article formed by a wet method will be described in detail as a specific example, but the present invention is not limited to this. A gas-permeable low-density molded article formed by a wet method supplies slurry into a mold having a large number of small holes on a wall surface, and removes water, which is a medium of the slurry, from the small holes. It is obtained by depositing fine components in a mold to form a wet molded product and then performing a drying treatment. As the mold, a concave mold having one open surface is usually used. As the small hole of the molding die, a circular hole having a diameter of 1 to 10 mm is usually used, and the molding die has a surface of 15 to 200 mesh on the surface of the mold having the small hole like a pulp mold. A mold with a wire mesh is usually used.

As a main raw material of the slurry composition, fibers, coarse powders and fine particles composed of environmentally friendly natural organic polymers are usually used. In addition, synthetic organic polymers, semi-synthetic organic polymers, inorganic substances and The effect of the present invention can also be expected in the case of a molded article mainly composed of fibers, coarse powder, fine particles, etc. made of an organic-inorganic composite material. These raw materials are used alone or in combination. Among them, preferred as a main raw material are fibers from which a molded article with good performance can be obtained, and among them, natural organic polymer fibers are particularly preferred because they are also excellent in environmental aspects.

As natural organic polymer fibers, for example,
(1) Unbleached or bleached chemical pulp obtained by kraft pulping, sulfite pulping, alkali pulping of coniferous or hardwood, mechanical pulp such as GP, TMP (thermomechanical pulp), cotton pulp, linter Pulp, used paper pulp, liquid ammonia-treated pulp, mercerized pulp, and curled fiber which have been subjected to at least one of water repellency, water resistance, and curing described in Japanese Patent Application No. 10-0322920. Product name: HBA-FF, NHB405, NH, manufactured by Warehauser, USA
B416), cellulosic fibers such as hemp fiber described in Japanese Patent Application No. 10-377923, (2) protein fibers such as wool, silk, and collagen fibers, (3) chitin / chitosan fibers and alginic acid fibers. And the like. Among them, cellulosic fibers are particularly preferable because they are excellent in performance and easy to procure.

In the slurry composition, materials are appropriately selected and blended according to the required characteristics of the molded article. When it is desired to increase the interlayer strength of the molded article, the number average fiber length obtained by fibrillating cellulose fibers with a sand grinder or the like is fine fibers having a range of 0.01 to 0.80 mm, or polyethylene fibers or polypropylene fibers. It is effective to mix thermoplastic synthetic fibers such as polyethylene-polypropylene sheath core fibers and biodegradable aliphatic polyester fibers. Above all, as the synthetic fiber, a short fiber having a number average fiber length in a range of 2 to 20 mm, which is easily dispersed at the time of slurry preparation, is particularly preferable. The fine fibers or synthetic fibers are usually blended in a range of 2 to 40% by dry weight with respect to the composition.

The slurry composition may further contain an adhesive, a waterproofing agent, a water repellent, a dye, a pigment, a drainage improver, a pH adjuster, a slime control agent, a thickener, and the like, if necessary.
Preservatives, fungicides, antibacterial agents, flame retardants, rodenticides, insecticides, humectants, freshness preservatives, oxygen scavengers, foaming agents, surfactants, electromagnetic shielding materials, antistatic agents, rust inhibitors, fragrances ,Deodorants,
Various microcapsules having foaming properties and aromatic properties can be selected and blended. These may be used in combination of two or more.

As the slurry composition of the present invention, a slurry composition having a good drainage of 550 ml or more of Canadian Standard Freeness (CSF), which can efficiently form a molded article having a thick sedimentary layer with excellent buffering property, is preferable. By the way, Canadian Standard Freeness is
Usually, it is a value indicating the drainage of pulp specified in JIS-P-8121. In the present invention, the drainage of the slurry composition was determined by the same measuring method.

The slurry is usually prepared batchwise or continuously by using an apparatus having a stirrer. Water is usually used as a medium used for forming a slurry, but a mixture of water and an alcohol (such as methanol or ethanol) can also be used. The concentration of the slurry is usually adjusted so that the dry solid content is in the range of 0.05 to 10% by weight, but preferably in the range of 0.05 to 3% by weight in terms of the dispersed state.

The injection of the slurry into the concave mold is performed by a known method. Examples of the method for removing the medium of the slurry from the small holes include a suction dehydration method, a gas pressure dehydration method, a mechanical pressure dehydration method, an electroosmotic dehydration method, and the like, and these can be combined. The dehydration conditions can be changed during the dehydration. The type of slurry used for injection is usually one type, but the injection of slurry is divided into two or more stages, and by changing the composition of the slurry used at that time, a state in which deposited layers of different compositions are sequentially laminated. Molded articles can also be obtained.

The wet molded product formed in the mold by dehydration is thereafter taken out of the mold or taken out of the mold and subjected to a drying treatment, but is dried in the mold to obtain a molded product with high dimensional accuracy. Is more preferred. Further, it is more preferable to apply a compression treatment to the molded product during drying in the mold or before the drying treatment, since a molded product which is less deformed by a load is obtained. As a drying method, for example, a known method such as hot-air drying, infrared drying, and microwave drying can be used. Above all, hot air ventilation drying, in which heating air is forcibly passed through the inside of a molded product by injecting heated air into a molded product in a wet state, or sucking in while applying heating air from the opposite side of the molded product, has a high drying speed. It is efficient. At that time, it is also effective to form a through hole or a non-through hole in the molded product to improve the air flow.

In the present invention, a composite is formed by combining the air-permeable low-density molded article obtained as described above and a good creep property object whose compression deformation is smaller than the low-density molded article. 0.1k as a good creep property object
An object having a compression deformation of 5% or less after 100 hours under a load of g / cm ² is preferable in terms of performance. In addition, as the composite cushioning material, a material in which a good creep property object is incorporated in a portion of a deposited layer having a thickness of 10 mm or more of a gas permeable low density molded body,
The balance between the buffering characteristics and the creep characteristics is particularly excellent and preferable. In addition, since the composite buffer material can be discarded or reused as a raw material without separation, a good creep property object made from a natural material or fiber is preferable. Specifically, paper tubes (square paper tubes, hollow L paper tubes, round paper tubes,
(Paper ring mat), cardboard, laminated cardboard, paper honeycomb structure, waste paper board, fiber board, particle board, wood, and the like.

The composite can be formed by a method such as bonding and / or fitting. Examples of adhesives and pressure-sensitive adhesives used for bonding include starch, processed starch, carboxymethylcellulose, hydroxyethylcellulose, vegetable gum, gelatin, casein, PVA, urea resin adhesive, melamine resin adhesive, and phenol resin adhesive. Agent,
Epoxy resin adhesive, vinyl acetate resin adhesive, cyanoacrylate adhesive, polyurethane adhesive, α-olefin-maleic anhydride resin adhesive, aqueous polymer-
Isocyanate adhesive, Reactive acrylic resin adhesive, Vinyl acetate resin emulsion adhesive, Vinyl acetate copolymer resin emulsion adhesive, EVA resin emulsion adhesive, Acrylic resin emulsion adhesive, Reaction Type hot melt adhesive, EVA type hot melt type adhesive, elastomer type hot melt type adhesive, polyamide type hot melt type adhesive, chloroprene rubber type solvent type adhesive, synthetic rubber type solvent type adhesive, synthetic rubber type latex Adhesives, acrylic resin-based emulsion-type adhesives, and the like, and these can be used alone or in combination. These are usually applied to the joint surface by dissolving in water or a solvent, or as an emulsion, or in a liquid state as it is, or in the case of a hot melt type, by heat melting. The coating amount is usually 0.1 to 30 g / m ² in terms of dry weight.

The composite cushioning material of the present invention or the fibrous molded product before composite can contain the above-mentioned adhesive by means of spraying, impregnation, coating or the like in order to prevent the fiber from falling off and to increase the strength. In addition, if necessary, a water-proofing agent, a water-repellent agent, a dye, a pigment, a preservative, a fungicide, an antibacterial agent, a flame retardant, a rodenticide, an insecticide, a freshness-retaining agent, a deoxidizer, an electromagnetic shielding material , An antistatic agent, a rust preventive, a fragrance, a deodorant and the like can be incorporated by the same means.

The composite cushioning material obtained by the present invention can be used by bonding other materials such as synthetic resin film, synthetic paper, water-resistant paper, water-repellent paper, and metal foil such as aluminum. Processing such as cutting and printing can be performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
In addition, here, description will be made using pulp slurry, but the raw material of the present invention is not limited to this. FIG.
FIG. 2 is a perspective view showing a pulp-based molded body 10 used as a material of the composite cushioning material of the present invention and a particle board 11 which is an object having good creep characteristics. FIG. 2 shows the two materials shown in FIG. FIG. 3 is a perspective view showing a composite cushioning material 12 of the present invention obtained by fixing the composite cushioning material. FIG.
FIG. 4 is a perspective view showing a concave mold 13 used for manufacturing the pulp-based molded body 10 of FIG. 1, and FIG. 4 is a cross-sectional view of the concave mold 13 shown in FIG. As shown in FIG. 4, the molding die used is a concave shape having an open top with a double wall, and has a large number of small holes 14 for dehydration on the inner wall. In addition, a suction chamber 16 is formed by the inner and outer double walls,
A suction port 15 is attached to the bottom of the outer wall.

FIGS. 5 to 8 are sectional views showing the steps of preparing a pulp-based molded product used in the present invention using the concave molding die 13 shown in FIG. In the present invention, after the surrounding frame 17 for slurry storage is attached to the upper part of the molding die 13,
As shown in FIG. 5, the molding die 13 and the slurry storage enclosure 1
A pulp slurry 19 having good drainage is supplied from a guide 18 into the cavity formed by the pulp slurry 19. Next, as shown in FIG. 6, the pulp deposit 20 is formed in the mold by suction dehydration through the suction port 15 provided at the lower part of the mold 13. At that time, the pulp is deposited so as to protrude from the open surface of the mold as shown in the figure and rise. Reference numeral 21 denotes water droplets that have oozed out by suction.

Next, as shown in FIG. 7, unnecessary portions deposited so as to swell on the open surface of the mold are cut off with a water jet 22 to prepare the surface. At that time, the suction port 15
, The suction is continued. Subsequently, as shown in FIG. 8, a press upper die 23 having a flat bottom surface and a plurality of small holes 24 for hot air injection on the bottom surface is provided on the smooth surface of the wet molded product whose surface has been cut and smoothed. After applying lightly, hot air is sent from the hot air injection port 25 of the upper die 23 while being sucked from the suction port 15 and dried. Reference numeral 26 denotes a molded product during drying. Thus, the pulp-based molded body 10 shown in FIG. 1 is obtained. The composite cushioning material 12 as shown in FIG. 2 is obtained by fitting and bonding and fixing the particle board 11 which is a good creep characteristic object.

As an effect similar to that of the composite cushioning material 12 shown in FIG. 2, a composite cushioning material 27 having a form as shown in FIG. 9 can be given. Hereinafter, the present invention will be described more specifically with reference to examples. However, needless to say, the present invention is not limited to these examples. In Examples and Comparative Examples, “part” and “%” are used.
Unless otherwise specified, "parts by weight" and "% by weight"
Is shown.

<Example 1> A jute hemp bag was cut with a cutting machine for 20 minutes.
After cutting to a cm square, a crusher (V-36, manufactured by Horai)
0), followed by a treatment for softening the fibers with a grinder mill (manufactured by Glow Engineering, GM4-25) to obtain hemp fibers having a number average fiber length of 7 mm. The Canadian standard freeness of this fiber was measured to be 728.
ml. Further, a water slurry of used newspaper pulp having a solid content of 1% was mixed with glass beads having an average particle size of 2 mmΦ by 8%.
Sand grinder for 1.5 liters filled with 0% (Dynomill KDL manufactured by Shinmaru Enterprises)
-PILOT) at a flow rate of 350 ml / min to obtain fine fibers having a number average fiber length of 0.31 mm.
The solid content concentration was adjusted to 2% by adding water to a mixture of 95 parts (dry weight) of hemp fibers and 5 parts (dry weight) of fine fibers obtained as above, and the slurry was sufficiently stirred to form a slurry. Obtained. The Canadian standard freeness of the slurry composition was 682 ml. Next, a circular hole having a diameter of 0.5 mm was formed on the entire inner wall so that the porosity was 15%, and a wire mesh of 40 mesh was further attached on the entire inner wall. A concave mold 13 as shown in a sectional view was prepared. Further, a slurry storage enclosure 15 is mounted on the molding die 13, and the slurry is supplied from a guide 16 into a cavity formed by the molding die 13 and the slurry storage enclosure 17 as shown in FIG. did. Subsequently, as shown in FIG. 6, dehydration was performed by suction through a suction port 15 provided at a lower portion of the molding die 13, and hemp fibers were deposited so as to swell on the open surface of the molding die. Next, FIG.
As shown in (2), unnecessary portions deposited so as to swell on the open surface of the mold are cut off with a water jet 22 to prepare the surface. Subsequently, as shown in FIG. 8, the upper surface of the press machine 23 having a flat bottom surface and a large number of small holes 24 for injecting hot air into the smooth surface of the wet molded product whose surface has been cut and smoothed. Was lightly applied, and hot air was sent from the hot air injection port 25 of the upper mold 23 to dry. A particle board, which is a good creep property object, was fitted into the hemp fiber-based low-density compact thus obtained, and was adhered and fixed with a vinyl acetate-based adhesive to obtain a composite cushioning material as shown in FIG. As a result of packing and evaluating a heavy material with the obtained composite cushioning material, it was found that the composite cushioning material had excellent cushioning properties and was hardly deformed.

[0026]

As described above, the air-permeable low-density molded article has:
By combining and combining an object whose compression deformation is smaller than that of the low-density compact (good creep characteristic object), a cushioning material exhibiting excellent characteristics with respect to a heavy buffered object (enclosed product) can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing materials (a molded body and an object having good creep characteristics) used for a composite cushioning material.

FIG. 2 is a perspective view showing a composite cushioning material obtained by combining the materials of FIG. 1;

FIG. 3 is a perspective view showing a concave mold used for manufacturing the molded body of FIG. 1;

FIG. 4 is a cross-sectional view of the mold of FIG. 3 taken along the line AA.

FIG. 5 is a cross-sectional view showing a state in which a slurry storage enclosure is set on the mold of FIG. 4 and then a slurry is supplied from a guide to fill the upper part.

FIG. 6 is a cross-sectional view showing a state in which pulp is deposited in a mold by suction dehydration from the state of FIG. 5 and an unnecessary portion is formed on an open surface of the mold.

FIG. 7 is a cross-sectional view showing a state in which unnecessary portions accumulated on the mold opening surface of the molded product after dehydration are cut off.

FIG. 8 is a cross-sectional view showing a state where hot air is injected into a wet pulp molded product in a molding die and dried.

FIG. 9 is a perspective view showing a composite cushioning member having a form different from that of FIG. 2;

[Explanation of symbols]

10: pulp-based molded article, 11: particle board (good creep property object), 12: composite cushioning material, 13: concave mold, 14: small hole, 15: suction port, 16: suction chamber, 1
7: Enclosure frame for slurry reservoir, 18: Guide, 19: Pulp slurry, 20: Wet pulp deposit, 21: Water drop, 22: Water jet (cutting device), 23: Press machine upper mold, 24: Small hole (For hot air injection), 25: hot air port, 26: molded product during drying, 27: composite cushioning material of another form

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shunsuke Shioi 4-7-5 Ginza, Chuo-ku, Tokyo Oji Paper Co., Ltd. F term (reference) 3E066 AA05 BA02 CA04 CA05 CA06 CA08 CB02 DA10 JA01 KA20 LA30 MA05

Claims (6)

[Claims] 1. A composite cushioning material comprising a combination of an air-permeable low-density molded article and an object whose compression deformation is smaller than the low-density molded article (referred to as an object having good creep characteristics). 2. The air-permeable low-density molded body supplies a slurry into a mold having a large number of small holes in a wall surface, and removes water as a medium of the slurry from the small holes to thereby reduce the size of the slurry. The composite cushioning material according to claim 1, wherein the composite buffer material is obtained by depositing a fine component that does not pass through the pores in a mold to form a wet molded product, and then performing a drying treatment. 3. The composite cushioning material according to claim 2, wherein the composition of the slurry used for producing the air-permeable low-density molded product has a Canadian Standard Freeness (CSF) of 550 ml or more. 4. The composite cushioning material according to claim 1, wherein a main raw material of the air-permeable low-density molded product is a cellulosic fiber. 5. The composite cushioning material according to claim 1, wherein the good creep property object is incorporated at a location of a deposition layer having a thickness of 10 mm or more of the air permeable low density molded body. 6. The good creep characteristic object is 0.1 kg /
5% compressive deformation after 100 hours under a load of cm ²
The composite cushioning material according to any one of claims 1 to 5, which is the following object.