JP2002339300A - Compound formed body of low density and a method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low density formed body of a piled system of fine components having extremely small deformation even against a large load and a method for manufacturing the same. SOLUTION: The formed body having extremely small deformation against a heavy load while holding light-weight, is obtained by carrying out forming operation in a state where a skeletal body exists.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-density composite molded article of a fine component deposition system which is less deformed by a load and an efficient production method thereof.

[0002]

2. Description of the Related Art Styrofoam is lightweight, has excellent strength,
It has been widely used in various fields, including packaging cushioning materials, because of its excellent performance such as shock-absorbing properties and heat insulating properties, and its low cost. However, in recent years, as interest in environmental issues has increased, like other so-called plastic products, there has been an increasing demand for treating the processability after use. That is, after using
In the case of incineration, it has been pointed out that damage to the furnace and generation of toxic gas due to the generation of high temperatures. 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.

In order to solve the problems in the processing of styrofoam, recently, a low-density molded product obtained by depositing a fine component such as pulp, specifically, a wet-processed high-filtration fiber is formed into a molding die. Low-density molded body (trade name: Green Pal: manufactured by Oji Bag) formed by filling into a mold, and thick low-density molded body (trade name: Cell Mold: Rengo)) and the like.

[0004]

However, what is obtained by depositing fine components such as pulp, such as the above-mentioned low-density molded article, does not have fine closed cells such as styrene foam inside and has a high air permeability. Since the material is a material, it exhibits excellent performance in applications where the load applied thereto is relatively small, but has a problem in that when the load is large, the internal air escapes and is greatly deformed and cannot be used. For example, when the product to be wrapped is relatively lightweight when used as a cushioning material for packaging, it can exhibit excellent cushioning properties and can be an excellent packaging material. Due to the fact that the deformation of the molded article gradually progresses with the passage of time, when the packaged goods are stored in several layers, so-called stacked storage, the load may be tilted and fall down due to the deformation Also, when the low-density molded article is used in a form in which a person or furniture, such as a flooring material for a house, a flooring material for heating, a flooring material for an automobile, a core material of a tatami mat, etc. And the load causes deformation such as dents. An object of the present invention is to provide a low-density molded product that is extremely small in deformation even under a large load while being a fine component deposition system. Another object of the present invention is to provide a method for efficiently producing the molded article.

[0005]

Means for Solving the Problems The present inventors have made intensive studies in view of the present situation, and as a result, by including a skeleton in a low-density molded product, and in a state where the skeleton is present when obtaining the same. The present inventors have found that a molded body having a small deformation with respect to a load can be easily obtained while maintaining a light weight by employing a molding method, and the present invention has been completed. That is, the present invention is a low-density composite molded article obtained by depositing fine components in the presence of a skeleton, and a method for producing the same. Further, the low-density molded body,
After setting the skeleton in a mold having a large number of small holes on the wall surface, a slurry containing fine components that are not allowed to pass through the small holes is poured into the mold, and water as a medium of the slurry is removed from the small holes. By doing so, it is preferable that the fine component which has not passed through the small holes in the slurry is deposited in the mold, and then dried. Especially, it is preferable that the composition of the slurry used for manufacturing the low-density molded product has a Canadian standard freeness (CSF) of 550 ml or more. Further, it is preferable that the skeleton is an aggregate of cylindrical objects. Especially, it is preferable that the skeleton is a cylindrical object aggregate having a fixed pattern. The skeleton is preferably a honeycomb core, a roll core, a corrugated core, or a lattice. Further, it is preferable that the main raw material of the fine component of the low-density molded product is a cellulosic fiber.

The success of the present invention is based on the fact that the combination of the above-described air-permeable low-density molded article and the skeletal body has the characteristic that the low-density molded article, which is less deformable under a large load, cannot be obtained by the low-density molded article alone. The advantage is that the low-density molded product can be drawn out without impairing its light weight and other features. In addition, as a method of incorporating the skeleton, instead of a method of manufacturing a molded body having a void in which the skeleton can be fitted in advance and then fitting the molded body, a fine component is deposited with the skeleton set in advance. By adopting this method, it has been found that this can be easily achieved without using a special and expensive mold and without going through a complicated step of fitting. In addition, in the case of this method of depositing fine components in the presence of a skeleton, unlike the case of depositing without a skeleton, the deposition is slightly inhibited and the density is unexpectedly lowered. It is found that it has an unexpected effect.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the low-density molded product used in the present invention, a molded product such as a cell mold (made by Rengo) molded by a dry process or a green pal (made by Oji bag) molded by a wet process is used. And the like, but a low-density molded body obtained by a wet manufacturing method is preferable in that it is excellent in quality such as strength and a stable product having little variation in quality can be obtained. Although the density varies depending on the material of the molded body and is not particularly limited, it is usually 0.05 to
It is in the range of 0.5 g / cm ³ .

[0008] The skeleton is preferably a structure that does not hinder the deposition of fine components as much as possible during molding and that allows fine components to penetrate into every corner. Examples of the structure include a structure having a wall only in a direction perpendicular to the deposition surface. Specifically, the cross section is circular, square,
Hexagonal cylinders and the like, and aggregates of the cylinders can be mentioned. Above all, an aggregate of cylindrical objects is preferable in terms of the effects of the present invention, and a cylindrical object aggregate having a fixed pattern is most preferable in that a molded article having uniform strength is easily obtained. Preferable examples of the cylindrical object aggregate having a fixed pattern include a honeycomb core, a roll core, a corrugated core, and a lattice. The size of the cross section of one cylinder of the skeleton body is not particularly limited, but when the fine component used has a large particle size, it is difficult to enter into the cylinder, so it is necessary to select a large area. desirable. Usually, a material in the range of 1 to 50 cm ² is used. The material is not limited, but a natural type which is easy to dispose is preferable, and a paper type containing cellulose fiber as a component is preferable. The skeleton is preferably strong when wet with the slurry medium. When water is used as the medium, a relatively water-resistant skeleton is selected.

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. The low-density compact formed by the wet method is a method in which a slurry is supplied into a mold having a large number of small holes in a wall surface, and water as a medium of the slurry is removed from the small holes, whereby fine components that do not pass through the small holes in the slurry. Is formed in a mold to form a wet molded article, and then subjected to a drying treatment. As the mold, a concave mold having one open surface is usually used. In the present invention, at the time of molding, the skeleton is set in a mold. As the mold, a mold having a 15-200 mesh wire mesh attached to the surface of a mold having small holes like a mold of a pulp mold is usually used. As a small hole of the mold, usually 1 ~ 10mm in diameter
Are used.

[0010] As the main raw material of the slurry composition, fibers, coarse powder and fine particles composed of an environmentally friendly natural organic polymer are usually used. In addition, synthetic organic polymers, semi-synthetic organic polymers, inorganic substances and Some of the effects of the present invention can be expected even when fibers, coarse powders, fine particles, and the like made of an organic-inorganic composite material are used as main raw materials. 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, pulp that has been subjected to at least one of water repellency, water resistance, and curing, waste paper pulp that has been subjected to the treatment (Japanese Patent Application No. 10-0322920), liquid ammonia-treated pulp, and mercerization Pulp, curled fiber (product name: HBA-FF, manufactured by Warehauser, USA)
NHB405, NHB416), Japanese Patent Application No. 10-3779.
Cellulose fiber such as hemp fiber described in specification 23,
(2) protein fibers such as wool, silk and collagen fibers;
(3) Complex sugar chain fibers such as chitin / chitosan fibers and alginic acid fibers. 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 in accordance with the required characteristics of the molded article. When it is desired to increase the interlayer strength of the molded product, natural fibers such as pulp are refined with a sand grinder or the like, and the number average fiber length obtained by fibrillating the natural fibers is in the range of 0.01 to 0.80 mm. It is effective to mix fibers or thermoplastic synthetic fibers such as polyethylene fibers, polypropylene fibers, polyethylene-polypropylene sheath core fibers, and biodegradable aliphatic polyester fibers. The synthetic fiber has a number average fiber length of 2 to 20 mm that can be easily dispersed during slurry preparation.
Short fibers in the range are particularly preferred. These natural fine fibers and thermoplastic synthetic fibers are used alone or in combination of two or more, and are usually blended in a range of 2 to 40% by dry weight with respect to the composition.

The strip-shaped waste paper described in Japanese Patent Application No. 2000-105555 is excellent in performance and is preferable as a material used in combination with the above-mentioned cellulosic fiber. Usually, it is blended in a range of 5 to 80% by dry weight with respect to the composition. Further, a crushed rice hull is also preferable as a material used in combination with the cellulosic fiber, and is usually blended in a range of 5 to 60% 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,
A foamed resin pulverized product, various microcapsules having foaming properties, aromatic properties and the like can be selected and blended. These may be used in combination of two or more.

The slurry composition of the present invention is preferably a Canadian standard freeness of 550 ml or more, which can efficiently form a molded product having a thick sedimentary layer with excellent buffering properties, and has a good filterability. However, depending on the cylindrical cross section of the skeleton body or the shape and size of the core, the deposition of fine components may be greatly hindered. In such a case, it is necessary to select a fine material as a raw material at the expense of filterability. There is. Incidentally, the Canadian Standard Freeness is a value that normally indicates the drainage of pulp specified in JIS-P-8121. In the present invention, the drainage of the slurry composition was determined by the same measurement 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. Methods for removing the medium of the slurry from the small holes include, for example, a suction dehydration method, a gas pressure dehydration method, a mechanical pressure dehydration method, and an electroosmotic dehydration method, and a combination thereof.

The wet molded article formed in the mold by dehydration is then 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 article with high dimensional accuracy. Is more preferred. 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 heated air is forcibly passed inside the molded product by injecting heated air into a wet molded product or sucking in while applying heated air from the opposite side of the molded product, has a drying speed of Fast and efficient.

The shape of the molded article used in the present invention is not particularly limited, and examples thereof include those having a block shape, a board shape, those having an uneven shape, and those having no.
The thickness is not particularly limited, but usually a few mm
To tens of cm. In the present invention, in order to suppress deformation of the molded body under load, the skeleton is set at the time of molding, and the skeleton is incorporated into the molded body to form a composite. In addition to being present in the entire molded body, it can also be locally present in a place where no particular deformation is desired.

The molded body thus obtained is sprayed, impregnated, coated, etc. to increase the surface strength, etc., by using starch, PVA, CMC, vinyl acetate resin emulsion,
Adhesives such as acrylate resin-based emulsions, ethylene-vinyl acetate copolymer emulsions, styrene-butadiene copolymer emulsions, etc., or the above-mentioned natural fibers obtained by pulverizing natural fibers such as pulp with a sand grinder or the like. Surface treatment can be performed with fine fibers of the type. In addition, if necessary, a water resistance agent, a water repellent, a dye, a pigment, a preservative, a fungicide, an antibacterial agent, a flame retardant,
Raticides, insect repellents, freshness preserving agents, oxygen scavengers, electromagnetic shielding agents, antistatic agents, rust inhibitors, fragrances, deodorants, etc. can be contained by similar means. As a means for increasing the surface strength, it is also effective to attach a sheet such as a film or paper to the surface of the molded body.

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. 1 is a perspective view of a molding die 10 used for wet molding, and FIG. 2 is a cross-sectional view of the molding die 10 taken along the line A-A. As shown in FIG. 1, a molding die 10 is an open-top type having a large number of small holes 11 for dehydration on an inner wall, and a suction chamber 12 is formed by inner and outer double walls. A mouth 13 is attached.

FIG. 3 is a perspective view of a lattice (collection of cylindrical bodies having a square cross section) 14 serving as a skeleton, and FIG. It is a figure and the sectional view in the BB plane is FIG. In the present invention,
First, as shown in FIG. 5, the lattice-like skeleton 14 is fitted into the molding die 10, and then, as shown in FIG.
A slurry storage enclosure 15 is set on the top, and a pulp slurry 17 having good drainage is supplied from an upper guide 16 into a cavity formed by the molding die 10 and the slurry storage enclosure 15. Next, as shown in FIG. 7, pulp deposits 19 are formed in the mold by suction dehydration from the suction port 13 at the lower part of the mold 10. 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. Numeral 18 denotes a water droplet that has oozed out by suction.

Next, as shown in FIG. 8, the unnecessary portion protruding from the open surface of the forming die and deposited is cut off with a tip saw (disk-shaped blade) 20. Subsequently, as shown in FIG. 9, the upper surface of the press machine having a flat bottom surface and a large number of small holes 22 for hot air injection on the smooth surface of the wet molded product whose surface has been smoothed by cutting with a tip saw. After bringing the 21 into close contact, hot air is sent from the hot air inlet 23 of the upper mold 21 and dried. Numeral 24 is a molded product during drying.

FIG. 10 is a sectional view showing a state in which air is blown from the suction port 13 after the drying is completed to take out the molded product. FIG. 11 is a sectional view of the low-density composite molded body 25 thus obtained, and FIG. 12 is a perspective view thereof.

The following figures show a different type of skeleton used in the present invention. FIG. 13 is a perspective view showing a roll core 26, FIG. 14 is a perspective view showing a honeycomb core 27, and FIG. is there.

The obtained molded body is used in combination with another material as required. As an example, the sandwich panel 3 obtained by the method shown in the perspective view of FIG.
2 and the like. 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 into 20 pieces by a cutting machine.
After cutting to a cm square, a crusher (V-36, manufactured by Horai)
By pulverizing in 0), hemp fibers having a number average fiber length of 5 mm were obtained. The Canadian standard freeness of this fiber was measured to be 705.
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.
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 pulp fibers having a number average fiber length of 0.27 mm. 85 parts of the hemp fiber (dry weight) and 5 parts of the pulp-based fine fiber (dry weight) obtained as described above were further combined with a copolyester-polyethylene terephthalate sheath-core fiber (TSF. TJ04CN 2.2 ×, manufactured by Teijin Limited). 5) 10
(Dry weight), water was added to adjust the solid content concentration to 1.5%, and the mixture was sufficiently stirred to obtain a slurry.
The Canadian standard freeness of this slurry composition was measured and found to be 643 ml. Next, the inner wall is 250m
m having a square bottom surface and a depth of 40 mm, a circular hole having a diameter of 6 mm provided on the bottom surface, and a wire mesh of 40 mesh attached thereto, as shown in FIG. Was prepared. Next, as shown in FIG. 5, a roll core (manufactured by Hokuyo Paper, S-140) is fitted into the mold, and then, as shown in FIG. The guide 1 is located in the cavity formed by the mounting and molding die 10 and the slurry reservoir enclosure 15.
From 6 the above slurry was supplied. Subsequently, as shown in FIG. 7, suction dehydration was performed from the lower suction port 13 to deposit fibers so as to swell on the open surface of the mold. Next, as shown in FIG. 8, the tip saw 20 is moved horizontally to cut off unnecessary portions of the deposits to form a smooth surface. Subsequently, as shown in FIG. 9, the bottom surface is flat and many small holes are formed in the bottom surface. After the upper die 21 having a press 22 was brought into close contact with the smooth surface, hot air was fed from a hot air inlet 23 of the upper die and dried to obtain a molded body having a roll core as a skeleton. As a result of packing and evaluating a heavy object with the obtained composite molded body, it was found that the composite molded body had excellent cushioning properties and was extremely hard to be deformed by a load.

[0028]

As described above, the present invention obtains a low-density composite molded article by depositing fine components in the presence of a skeletal body. can get.

[Brief description of the drawings]

FIG. 1 is a perspective view of a mold used for wet molding.

FIG. 2 is a cross-sectional view of the mold of FIG. 1 taken along the line AA.

FIG. 3 is a perspective view of a lattice serving as a skeleton (an aggregate of cylindrical objects having a rectangular cross section).

FIG. 4 is a perspective view showing a state where the skeleton is set in a molding die.

FIG. 5 is a sectional view taken along the plane BB in FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which a surrounding space for slurry storage is set on a molding die, and then a slurry is supplied from a guide to fill the upper portion.

7 is a cross-sectional view showing a state in which the slurry is sucked and dehydrated from the state of FIG. 3 and pulp is deposited on a molding die.

FIG. 8 is a cross-sectional view showing a state in which an unnecessary portion deposited on the open surface of the mold is cut off with a tip saw.

FIG. 9 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. 10 is a cross-sectional view showing a state in which air is blown from a suction port to take out a molded product after drying is completed.

FIG. 11 is a cross-sectional view of a low-density composite formed body having a skeleton.

FIG. 12 is a perspective view of the low-density composite molded product of FIG. 11;

FIG. 13 is a perspective view showing a roll core.

FIG. 14 is a perspective view showing a honeycomb core.

FIG. 15 is a perspective view showing a corrugated core.

FIG. 16 is a perspective view showing that a sandwich panel is manufactured using the low-density composite molded article of the present invention.

[Explanation of symbols]

10: concave mold, 11: small hole, 12: suction chamber, 13:
Suction port, 14: skeletal body, 15: enclosure for slurry reservoir,
16: guide, 17: pulp slurry, 18: water drop, 1
9: wet pulp deposit, 20: tip saw, 2
1: Upper press machine, 22: Small hole, 23: Hot air inlet, 2
4: molded article during drying treatment, 25: low-density composite molded article, 2
6: roll core, 27: honeycomb core, 28: corrugated core, 29: surface material, 30: adhesive, 31: middle core of a low-density composite molded body having a skeleton, 32: sandwich panel.

Claims (6)

[Claims] 1. A low-density composite molded article obtained by depositing fine components in the presence of a skeleton, and a method for producing the same. 2. A mold having a large number of small holes in a wall surface.
After setting the skeleton, a slurry containing small pore non-passing fine components is poured into the mold, and water as a medium of the slurry is removed from the small pores to remove the small pore non-passing fine components in the slurry. 2. The low-density composite molded article according to claim 1, which is obtained by depositing in a mold and then drying. 3. The low-density composite molded article according to claim 1, wherein the skeleton is an aggregate of cylindrical articles, and a method for producing the same. 4. The low-density composite molded article according to claim 3, wherein the skeleton is a cylindrical pattern aggregate having a fixed pattern. 5. The low-density composite molded product according to claim 4, wherein the skeleton is a honeycomb core, a roll core, a corrugated core, or a lattice. 6. The low-density composite molded article according to claim 1, wherein a main component of a fine component of the low-density molded article is a cellulosic fiber.