JP2000027099A - Production of uneven molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet molding method capable of applying even for pulp benign to the environment or the like and producing high strength molded products effectively. SOLUTION: This production method comprises using slurry consisting of pulp having >=550 ml Canadian standard freeness (CSF), removing an aqueous medium of the slurry through holes of a mold having many holes 11 and depositing small ingredients impassable the small holes so as to form a molded product 16 and drying the wet molded product in or out of the mold in the condition of blowing hot air through deposit layers. The drying is performed in the condition such as blowing hot air through deposit layers at >=2 L/cm2.min flow rate and high strength molded products are effectively produced by pressing the resultant so as to increase its density more than twice before pressing treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet molding method capable of efficiently producing a high-strength molded product from natural pulp or the like.

[0002]

2. Description of the Related Art In recent years, as interest in environmental problems has increased, pulp molds made of natural pulp, which is biodegradable and has no problems such as damage to incinerators due to high temperature generation such as plastic, have been packaged. It is attracting attention in the field of materials and the like.

In this pulp molding method, pulp in a slurry is deposited on a mold having a large number of small holes while sucking and dewatering, and then the obtained wet molded product is heated and dried in the mold. It is a wet molding method to obtain a molded product by drying inside, or by drying outside the mold by taking out a wet molded product from the mold and heating and drying, and from the manufacturing principle, if it can be sucked and dewatered as a slurry, Materials other than natural pulp, such as rice husk, bran, and beer lees, can also be used as raw materials.

[0004]

As described above, various materials can be selected as a raw material for the pulp molding method. However, if an environmentally friendly natural pulp is to be obtained as a raw material, a fiber-to-fiber mixture is required. It is common to select a pulp that is easily entangled with and easily forms a hydrogen bond. But,
Since such raw materials have poor drainage, as the pulp accumulation in the mold progresses, the adhesion between the pulp fibers progresses, the drainage becomes poor, and the accumulation is slowed down. In order to obtain such a material, a long time is required for the suction / dehydration step, and unless the production efficiency is neglected, a material having a deposited thickness exceeding 5 mm which can be used as a packaging material for heavy goods cannot be obtained. Further, as a special method, there is a method in which the slurry is forcibly dewatered by sending it under pressure during suction and dehydration to obtain a slurry having a thickness of about 10 mm, but this method also requires a considerable amount of time for dehydration. Furthermore, wet molded products obtained using such raw materials having poor drainage are inferior in dryness. Among them, when the thickness of the molded products is large, the internal drying is poor, and using a high-performance drying device. However, there was a problem that the drying speed did not increase.
Also, when drying the wet molded product with poor drying properties in the mold,
Since the time to stop in the mold becomes particularly long, productivity cannot be improved unless a large number of special and expensive molds are prepared.
Products from industries with fast model changes or industries with small lots and many varieties cannot be manufactured at low cost. In particular, the present invention has a problem that it is particularly prominent in the case of a thick product. It is to provide a molding method.

[0005]

In view of the current situation, the present inventors have conducted intensive studies on a wet molding method capable of efficiently producing a high-strength molded product, and as a result, have conventionally selected a raw material for a high-strength molded product. By selecting a material with high drainage, which did not have any problem, as a raw material, and further employing a method not conventionally employed as a processing method, it has been found that this can be achieved, and the present invention has been completed. That is, the present invention uses a slurry comprising a composition having a Canadian Standard Freeness (CSF) of 550 ml or more to remove water, which is a medium of the slurry, from the pores of a mold having a large number of pores. A small component that does not pass through the pores in the slurry is deposited on the molding die to form a molded product. Then, the molded product in a wet state is heated inside or outside the mold by a heating air flow rate of 2 in the deposition layer.
It is a method for producing a concavo-convex molded body, characterized by drying under conditions that flow at a rate of not less than liter / cm ² · min, and then increasing the density to at least twice the density before pressing by applying a pressure treatment. . In the present invention, it is preferable that the concavo-convex molded body has a portion having a thickness of 10 mm or more. In the present invention, the heat treatment is preferably performed during or after the pressure treatment. In the present invention, the slurry composition preferably contains a heat-fusible component. In the present invention, it is preferable to supply the adhesive from the surface of the molded product before or after the pressure treatment. In the present invention, the main component of the slurry composition is preferably a cellulosic fiber. Above all, it is preferable that the cellulosic fiber is used paper fiber which has been subjected to at least one of water repellency, water resistance, and curing. Especially, it is preferable that the cellulosic fiber is a curled fiber. In the present invention, it is preferable that the main component of the slurry composition is a cellulosic coarse powder. Above all, it is preferable that the cellulosic coarse powder is obtained by mechanically pulverizing wood.

The first cause of the success of the present invention is to replace the fiber which is conventionally used as a raw material for obtaining a high-strength product with a fiber which is easily entangled and easily forms a hydrogen bond but has poor drainage. The fact that the fibers are not easily entangled and hydrogen bonds are unlikely to occur, but have good drainage properties is selected as the raw material for the slurry. It has been produced efficiently. In addition, the second cause of the success of the present invention is that the drying of wet molded products is extremely fast by performing aeration drying under specific conditions that can make use of the porous nature of the molded products obtained from the raw materials. It is in. The third cause of the success of the present invention is to apply a pressure treatment to the molded product after drying, to increase the density more than twice, to reduce the voids between the compositions, and to improve the adhesion to each other. Is that the strength can be greatly improved. A fourth cause of the success of the present invention is that, by combining the above-described methods, a high-strength molded product that could not be achieved by the conventional method,
The point is that it has been found that the system can be produced extremely efficiently.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses a slurry comprising a composition having a Canadian Standard Freeness (CSF) of 550 ml or more, and removes water as a medium of the slurry. The passing fine components are deposited to form a wet molded product, and then the wet molded product is dried in a mold or outside the mold under conditions such that heated air flows through the deposition layer at a flow rate of 2 liter / cm ² · min or more. Subsequently, a pressure treatment is performed to increase the density to at least twice that before the pressure, thereby obtaining a high-strength uneven molded body.

In the present invention, a composition having a Canadian Standard Freeness (CSF) of 550 ml or more is used.
When the volume is 0 ml or more, the effect of the present invention is particularly remarkable. The main ingredient of the composition is Canadian Standard Freeness (CS
Any material can be used as long as F) is 550 ml or more and most of the fine particles are impervious to the small holes of the mold. Among them, fibers made of natural organic polymers, which are environmentally friendly materials, can be used. Coarse powder and fine particles are particularly preferable because they can be easily disposed after use of the molded article. The size of the raw material is not particularly limited, and the dispersibility when making a slurry,
Considering the raw material yield during molding, usually 0.1 to 50mm
Are used. These raw materials may be used in combination of two or more. Naturally, raw materials recovered for recycling can also be used. The following are more specific examples of the raw material.

Examples of the natural organic polymer fibers include cellulose fibers such as pulp, protein fibers such as wool, silk and collagen fibers, and complex sugar chain fibers such as chitin / chitosan fibers and alginic acid fibers. . Examples of the natural organic polymer coarse powder / fine particles include cellulose-based coarse powder. Among them, cellulosic materials such as cellulosic fibers and cellulosic coarse powder are most preferable because raw materials can be easily obtained. Among them, fibers or coarse powders made of wood are particularly preferable because they can easily obtain the raw materials and can obtain a molded article excellent in physical properties such as strength. Above all, in the manufacturing process, those whose freeness has been increased through a step of removing fine components such as at least once from a 30 to 200 mesh pass treatment, the drainage treatment at the time of manufacturing the molded body is easy, Raw material yield is good and preferable.

[0010] As the cellulosic fiber, specifically,
Unbleached or bleached chemical pulp obtained by kraft pulping, sulfite pulping, alkali pulping of coniferous or hardwood, or mechanical pulp such as GP, TMP (thermo-mechanical pulp), cotton pulp, linter pulp Liquid pulp, mercerized pulp, pulp that has been subjected to at least one of water repellency, water resistance, and curing, and pulp that has been curled. Among them, waste paper fibers that have been curled,
Alternatively, waste paper fibers that have been subjected to at least one of water repellency, water resistance, and curing, or those that have been further subjected to a curl treatment, have a high drainage rate and are significant in terms of dealing with environmental problems. Yes, particularly preferred. As the machine used for the curl processing, any machine can be used as long as it can apply a shape deformation to the fiber, for example,
Machines such as kneaders, refiners, fluffers and the like can be mentioned. Examples of the water-repellent, water-resistant, and curing treatments include a cellulose-reactive reagent, a water-repellent treatment reagent, a water-resistant treatment reagent, a waterproof treatment reagent, and the like, which are generally used for cellulose fiber processing. it can.

Examples of the fibrin reaction type reagent include a fiber cross-linking agent as described in US Pat. No. 2,971,815, and more specifically,
I. Aldehydes (formaldehyde and dialdehydes such as glyoxal and glutaraldehyde), b. N
-Hydroxymethyl compounds (formaldehyde, urea, cyclic urea, triazine, amide, acrylamide,
Reaction products with carbamates and the like, such as dimethylolurea, dimethylolethyleneurea, trimethylolmelamine, N-methylolamide, N-methylolacrylamide, ethylene-bis-N-methylolcarbamate, etc .; Divinyl compounds (such as divinyl sulfone),
D. Halogen compounds (dichloroacetone, 1,2-dichloropropanol, 2-chloromuconic acid, cyanuric chloride, dichloroacetic acid, etc.); Epoxy compounds (halohydrins such as epichlorohydrin, butadiene diepoxide, polyepoxides such as polyglycidyl ether, etc.),
F. Aziridinyl compounds (Tris- (aziridinyl) phosphine oxide, Tris- (aziridinyl) phosphine sulfide, carbonyl-bis-aziridine, etc.); Polycarboxylic acids (maleic acid, citric acid, tricarballylic acid, melitic acid, cyclopentanetetracarboxylic acid, etc.); Acid anhydrides (phthalic anhydride, maleic anhydride,
Succinic anhydride, etc.); Polyvalent isocyanates (hexamethylene diisocyanate, 2,4-tolylene diisocyanate, etc.); And quaternary ammonium salts (such as quaternary ammonium derivatives of Bis-chloromethyl ether).

The reagents used for water repellency, water resistance and waterproofing include, for example, chemical bond type and adhesive type. Examples of the chemical bond type include acid chloride type water repellent and isocyanate type water repellent. Agent, ketene dimer type water repellent, pyridine condensation type water repellent, ethylene urea type water repellent, methylol compound type water repellent, ethylene oxide type water repellent, silicon compound type water repellent, chromium complex type water repellent Agents, titanium-containing compound-type water repellents, zirconium-containing compound-type water repellents, and the like. Examples of the adhesive type include a fluorine compound type water repellent, a silicon compound type water repellent, a rosin resin, a terpene resin, a natural rubber, a synthetic rubber, a hydrocarbon resin, an acrylic resin, a vinyl acetate resin, and a vinyl chloride resin. , Polyamide resins, fats and oils (vegetable oil, animal oil, vegetable fat, animal fat), higher aliphatic compounds (saturated or unsaturated acids, alcohols, esters, amines,
Amides, salts), waxes (vegetable wax, animal wax, mineral wax, petroleum wax, modified wax) and the like.

The above treating agents can be used alone or in combination of two or more. In addition, these can be used as they are, in a molten state, or in a form dissolved, mixed, emulsified, or dispersed in a medium. Further, some chemicals can be used after being further modified. The amount of the treatment agent is not particularly limited, but is usually added in the range of 0.2 to 50 parts (solid content) based on 100 parts of dry waste paper.

The treatment of water repellency, water resistance, and curing is performed before, during, or after defibration.
The treatment is carried out by contacting the dried paper or the waste paper in the form of wet paper or waste paper fibrillated fiber with the above-mentioned treating agent to cause a reaction or adhere to the surface, and further performing a drying treatment or a reaction accelerating treatment as necessary. . As a method of contacting the used paper or the used fiber with the treating agent, for example, impregnation, coating, spraying, mixing, or the like can be used. At that time, in the process of water repellency, water resistance, and curing, the waste paper or waste paper defibrated fiber obtained at least once in a dry state having a solid content concentration of 90% or more is obtained as a fiber. The reaction state or adhesion state of the treatment agent is good, and particularly preferable.

As a method for performing both the water repellency, water resistance, curing treatment and curl treatment, the fiber is deformed while or after the above-mentioned treating agent is added to the used paper fiber during or after the defibration treatment. Mechanical stirring, followed by fluffing and heat treatment.

In the present invention, in the case where fibers obtained from waste paper are used, the freeness is increased through a step of removing fine components such as a 30-200 mesh pass treatment at least once in the fiber production process. What was given
It is preferable because the wastewater treatment during the production of the molded body is simple and the raw material yield during the production of the molded body is good. In addition, as used paper used as a raw material, there can be used those known in the art, such as used newspaper, used corrugated paper, used magazine and the like discharged from homes, factories, business establishments and the like.

As the cellulosic coarse powder, specifically,
Cellulose-based coarse powder obtained by coarsely pulverizing a cellulosic material such as wood chips, bacas, rice straw, and rice hulls, rice husk itself, sawdust, bran, beer lees, soybean lees, and the like. Among them, preferred are coarse powders obtained by roughly pulverizing wood chips as described above, and examples thereof include fiberboard raw materials obtained by a fiberboard industry known method such as asplund method. Among the coarse powders, 30 to 20
In the case where the freeness value is increased by removing a fine region by passing through a 0 mesh pass, the drainage treatment at the time of manufacturing a molded article is easy, and the yield of raw materials at the time of manufacturing a molded article is good, which is preferable.

A slurry is prepared from the above-mentioned raw materials. However, depending on the raw materials, the bonding strength between the raw materials is weak, and when the molded body is taken out of the molding die, the interlayer strength is insufficient to cause breakage. However, in such a case, if necessary, a component having an effect of increasing the interlayer strength, for example, an adhesive, fibers / fine fibers, heat-fusible particles, and the like are added to the slurry. Above all, it is particularly preferable that the component has heat fusibility, because the strength is remarkably improved during a pressure treatment or a heat treatment after the treatment in a post-process of the dried molded article.
Among these, heat-fusible fibers and fine fibers are particularly preferable because the effect of improving the strength is particularly remarkable and a molded article having a uniform strength is easily obtained. The compounding amount is usually in the range of 2 to 40% by dry weight with respect to the composition.

Examples of the adhesive include starch, processed starch, vegetable gum, gelatin, casein, PVA, CMC,
Hydroxyethyl cellulose, urea formaldehyde resin, melamine formaldehyde resin, polyamide urea formaldehyde resin, ketone resin, polyamide epichlorohydrin resin, polyamide polyamine epichlorohydrin resin, glycerol polyglycidyl ether resin,
Examples include a vinyl acetate resin emulsion, an acrylate resin emulsion, an ethylene-vinyl acetate copolymer emulsion, and a styrene-butadiene copolymer emulsion.

Examples of the fibers and fine fibers include synthetic fibers of polyethylene fiber, polypropylene fiber, polyethylene-polypropylene sheath fiber, polyacrylonitrile fiber, acrylic fiber, rayon fiber, aromatic polyester fiber, aliphatic polyester fiber, polyamide fiber and the like. Semi-synthetic polymer fibers such as polymer fibers and acetyl cellulose fibers, or these synthetic polymer fibers, semi-synthetic polymer fibers, and the above-mentioned natural polymer fibers are mixed with a medium stirring mill, a vibration mill, and a high-pressure homogenizer. Fibers obtained by wet processing with an apparatus, a colloid mill, a beating machine or the like can be used. Among synthetic polymer fibers or semi-synthetic polymer fibers, biodegradable fibers or water-soluble fibers are preferable because they have advantages such as environmental friendliness. Further, a synthetic polymer fiber or a semi-synthetic polymer fiber that has been subjected to a deformation treatment such as curling has an effect of increasing the drainage of the slurry composition, and is therefore preferable.

Examples of the heat fusible particles include polyethylene, polystyrene, polylactic acid, aliphatic polyester,
Resin particles such as acetylcellulose can be mentioned, and among them, those having biodegradability or water solubility are environmentally friendly and preferable.

The slurry composition may further contain a water-proofing agent, a water-repellent agent, a sizing agent, a dye, a pigment, a retention agent, a filler, a pH adjuster, a slime control agent, a thickener, if necessary. , Preservatives, fungicides, antibacterial agents, flame retardants, rodenticides, insecticides, moisturizers, freshness preservatives, oxygen absorbers, microcapsules, foamable microcapsules, foaming agents, surfactants, electromagnetic shielding materials, electrification Inhibitors, rust inhibitors, fragrances, deodorants and the like can be selected and blended. These may be used in combination of two or more. The compounding amount is usually in the range of 0 to 20% by dry weight based on the composition.

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 other organic solvents such as alcohol, acetone, ethyl acetate, and glycerin, or a mixture of water and an alcohol (methanol or ethanol) can also be used. . When a mixture of water and alcohol is used, there are merits such as good drying properties and an increase in productivity, and a high-precision molded article with little dimensional change during drying. Heating the medium has the effect of increasing the drying rate. 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.

As a molding die, an ordinary pulp molding die can be used. However, when it is desired to obtain a molded product having different shapes on the front surface and the back surface, for example, a deep bottom having a large number of small holes is used. A container (for example, a cylindrical container such as a cylinder or a square tube) or a split container is usually used. (Hereinafter, the mold is referred to as a molding container in the present invention.) The small hole of the molding container may be any shape such as a circle, an ellipse, a square, and a rectangle. The size of the small holes may be such that the dispersed components other than water, which is the medium of the slurry, hardly leak, and a circular hole having a diameter of 30 μm to 3 mm is usually used. Is not particularly limited. Usually, when the impervious component is large, a larger one is used, and when it is small, a smaller one is used. Like a mold used in a pulp mold, a fine mesh (usually 30 to 1) is formed on a molding container wall having relatively large holes.
50 mesh) can be used. It is also possible to use two metal meshes (40 mesh and 100 mesh) having different meshes which are superposed and attached. Further, the size of the small hole can be changed in the portion of the molding container. Also, the small holes need not necessarily be present on the entire surface of the molded container wall, and may be present only on the bottom in the case of a cylindrical container. However, in consideration of the dewatering efficiency and the like, it is preferable that small holes are present in a portion of 50% or more of the wall of the molding container, more preferably 80% or more. The number of parts to in pores small pores there is preferably made present one or more per cm ^2, and more preferably four or more per cm ^2.

In the case of a cylindrical container, the slurry is poured into the molding container having an open port upward by a pump from the open port, and the slurry is opened downward as in a normal pulp mold. The slurry is immersed in the tank and sucked into the forming container from the downward opening by sucking through the small hole. It is possible to take a method such as sucking it inside. In the case of a split mold container, a method such as press-fitting into a molded container using a slurry injection tube can be employed. As a method for removing the medium of the slurry from the small holes, there are 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 shape and surface of the wet molded product obtained by suction dehydration can be adjusted as necessary by using a water flow such as a water jet.

For drying the wet molded product, for example, hot air drying,
Known methods such as infrared drying and microwave drying can be used, but as a means for flowing heated air into the deposition layer at a flow rate of 2 liters / cm ² min or more, for example, Injecting air into the layer, suctioning air in the layer while supplying heated air at normal pressure or pressure from the opposite side of the molded product, applying infrared or microwave to the molded product, Means such as injecting room temperature air or heated air under pressure into the deposition layer while applying infrared rays or microwaves to the molded product (in some cases, further suctioning air in the deposition layer). Can be. Among them, a method involving pressurized supply of heated air is preferred from the viewpoint of drying efficiency. The pressing condition at that time is 1 kg / cm ²
And more preferably 2 kg / cm ² or more,
In particular, it is preferably 4 kg / cm ² or more. As a method of pressurization, if you raise it all at once, the density of the molded body will increase,
It is preferable to gradually increase. As a drying condition, an air flow rate of 2 liters / cm ² · min or more is sufficiently effective, but a flow rate of 5 liters / cm ² · min or more is particularly preferable. In particular, the flow rate is preferably 10 liters / cm ² · min or more. Another effective means for increasing the drying efficiency is to form a through-hole or non-through-hole in the molded product to improve the air flow. Injecting air into the hole is particularly effective. For example, a method in which a tapered cylindrical projection having a small hole on the wall is inserted into the hole at the time of injection, and hot air is blown into the molded body from the small hole is effective. A heating air having a temperature of 100 ° C. or higher is usually used, and a heating air having a temperature of 150 ° C. or higher is preferable in terms of drying efficiency. For drying, nitrogen gas, heated steam, or the like can be used in addition to air, but air is most preferable in terms of drying efficiency and cost.

As a means for forming a penetrating or non-penetrating hole in a molded product, a wet molded product inside or outside a molding die is post-processed by using a pressing press machine, a cutting machine, a water jet, an air jet, or the like. And a method in which the shape is imparted to a molded product simultaneously with molding using a molded container having projections. The projections preferably have a tapered structure so that the molded product can be easily taken out of the container. Drying of the molded article includes in-mold drying in which the molded article is dried, and out-of-mold drying in which the molded article is taken out of the mold and dried. In-mold drying is preferred in that a molded article having high dimensional accuracy is obtained.

The pressure treatment of the dried molded product is performed using a mold usually used for molding or another mold, and is performed so that the density of the molded product is twice or more than that before the treatment. By this treatment, the voids between the compositions are reduced, the adhesion is increased, and the strength of the molded body is improved. However, from the viewpoint of the effect, the density is more preferably three times or more. It is particularly preferably at least four times. In order to further enhance the effect, it is preferable to perform a heat treatment on the molded article during or after the pressure treatment. In particular, in the case of a system containing a heat-fusible component, the effect of improving strength is particularly remarkable.

Examples of the method of heating the molded body include known methods such as hot air injection, mold heating, infrared rays, and microwaves. Hot air injection is most effective. The heating temperature is usually in the range of 80 to 250 ° C.

In order to improve the strength of the molded article, a means for supplying an adhesive from the surface of the molded article before or after the pressure treatment is performed by the above-mentioned method in which an adhesive component is previously contained in the slurry composition. It is effective, though inferior in production efficiency. As the adhesive used, for example, starch, processed starch, vegetable gum, gelatin, casein, PVA, CM
C, hydroxyethyl cellulose, urea formaldehyde resin, melamine formaldehyde resin, polyamide urea formaldehyde resin, ketone resin, polyamide epichlorohydrin resin, polyamide polyamine epichlorohydrin resin, glycerol polyglycidyl ether resin, SBR resin, vinyl acetate resin, acrylic resin, rosin resin, Terpene-based resins, natural rubbers, synthetic rubbers, and other UV or EB-curable resins can be used, and these can be used alone or in combination. These are usually applied by dissolving in water or a solvent, or as an emulsion, or in the case of a liquid, as they are. Among them, the use of an aqueous system is preferred in terms of the working environment. The application is usually performed by spraying, brushing, impregnation or the like. The coating amount is usually 5 to 50 g / m in dry weight.
² (with respect to the surface of the molded body). After application, drying and curing are performed using hot air, infrared rays, microwaves, ultraviolet rays, electron beams, or the like, as necessary.

Further, before or after the pressurizing treatment, the molded article of the present invention may be appropriately removed from the surface of the molded article as necessary.
Waterproofing agents, water repellents, dyes, pigments, fillers, preservatives, fungicides, antibacterial agents, flame retardants, rodenticides, insecticides, humectants, antistatic agents, rust inhibitors, fragrances, deodorants, etc. Can be supplied. These can be applied together with the above-mentioned adhesive. Also, a plurality of types can be used in combination.

Although the manufacturing method of the present invention can be applied to a material having a thin deposited layer, the most remarkable productivity of the present invention is exhibited by a molded article having a portion having a thickness of 10 mm or more. Is the case.

FIGS. 1 to 4 shown below show one example of the embodiment of the present invention in a sectional view, but the present invention is not limited to this. Also, here, a description will be given using a mixed slurry of pulp having good drainage properties and heat-fusible fibers as a slurry, but the raw material of the present invention is not limited to this. The molding container 10 is, as shown in FIG.
This is a relatively shallow double-walled container with an open top, having a number of small holes 11 for dewatering at a position lowered to a predetermined depth from the inner edge of the side wall, and a lower mold (male mold) having an uneven shape at the bottom. A suction chamber 13 is formed by the lower die (male type) 12 and the outer wall, and a suction port 14 is attached to the bottom of the outer wall.
FIG. 1 shows that the pulp is put on the lower mold 12 by lowering the molded container 10 in a mixed slurry tank (not shown) with the open surface of the container facing upward, and by suction-dehydration through a lower suction port 14. This shows a state in which a mixed layer of heat-fusible fibers is deposited thickly. Reference numeral 15 denotes a water droplet that has exuded by suction, and reference numeral 16 denotes a wet deposited layer.

FIG. 2 shows the deposited layer 1 in the wet state according to FIG.
6 shows a state in which the upper die 17 of the press is overlaid on the lower die 12 on which 6 is formed. That is, after the surface of the deposition layer 16 is smoothened by lightly compressing with a press upper die 17 having an uneven bottom surface and a large number of small holes 18 in the bottom surface, hot air is injected from a hot air inlet 19 of the upper die 17. This shows a state where the sheet is fed and dried. At this time, if suction is performed from the suction port 14, drying proceeds more efficiently. FIG. 3 shows that the molded product 16a dried by hot air feeding as shown in FIG. 2 is further strongly compressed by the upper die 17 of the press while blowing hot air from the hot air injection port 19 to melt the heat-fusible fibers. Mold density of 2
It shows a state that is more than doubled. FIG. 4 shows a final molded product 20 obtained by subsequently removing the molded product from the molded container 10.

The molded product obtained by the method of the present invention is
Packaging materials, building materials, alone or in combination with other materials
It can be widely applied to automobile parts.

[0037]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but it should be understood that the present invention is not limited to these examples.
In Examples and Comparative Examples, “parts” and “%” refer to “parts by weight of solid content” and “% by weight” unless otherwise specified.
Is shown.

<Example 1> A non-formalin-based cross-linking agent (trade name: Sumitex NF-500K, manufactured by Sumitomo Chemical Co., Ltd.) and a cross-linking assistant (100 g) of 100% non-beaten softwood bleached kraft pulp were dried. Product Name: Sumitex AC
100 g of an aqueous solution containing 5 g and 2 g of CELERATOR MX (manufactured by Sumitomo Chemical Co., Ltd.)
Was added and mixed well. The crosslinked agent-impregnated pulp is kept in a wet state in a 1-liter double-arm kneader (model:
S1-1, manufactured by Moriyama Seisakusho), and the kneading treatment was performed for 40 minutes by rotating the double arms at 60 rpm and 100 rpm at room temperature. Next, the kneaded pulp was placed in a Warburg blender in a wet state and fibrillated. Further, the fiber is taken out of the bag, put in a stainless steel vat, and heated at 150 ° C.
The mixture was heated in a blow dryer for 30 minutes to complete the crosslinking reaction, and curled fibers were obtained. The Canadian standard freeness (hereinafter, abbreviated as freeness) of the curled fiber was measured to be 753 ml. Also, a water slurry of bleached hardwood kraft pulp having a solid content of 1% was prepared using an average particle size of 2 mmφ.
Is introduced at 350 ml / min into a 1.5 liter Dynomill (model: KDL-PILOT, manufactured by Shinmaru Enterprises) filled with 80% of glass beads at a flow rate of 350 ml / min. Was obtained. 65 parts of the curled fiber obtained as described above, 5 parts of fine fibers, 30 parts of 1.3 mm fiber length polyethylene fiber (trade name: SWP, E-600, manufactured by Mitsui Chemicals) and water were added. The raw material slurry was adjusted so as to have a solid concentration of 1%. The freeness of the three types of mixed fibers was 703 ml. In the slurry tank, the forming container 10 is sunk with the open surface of the container facing upward, and as shown in FIG. A molded product 16 having a thickness of 40 mm was formed. Then, with the vacuum pump removed from the lower part and the air flow meter attached, as shown in FIG. 2 [pressing and molding lightly with a press upper die 17 having an uneven bottom surface and a large number of small holes 18 in the bottom surface. After smoothing the surface of the material, the pressure was increased from the hot air inlet 19 of the upper mold 17 by a compressor at a pressure of ² kg / cm ² to 180 ° C.
Hot air was sent) to dry the molded body. The time required for complete drying was 9.4 minutes. Also,
The hot air flow rate immediately before drying was 4.3 liter / cm ² · min. When the physical properties of the obtained molded body were measured, the thickness was 4
1 mm and a density of 0.12 g / cm ³ . Next, FIG.
Then, while blowing hot air from the hot air injection port 19 into the dried molded product to melt the polyethylene fiber which is a heat-fusible fiber, the molded product is strongly compressed by the upper mold 17 to increase the density of the molded product. T), thickness 10 mm, density 0.49 g
/ Cm ³ of the final molded product 20 was obtained.

Example 2 100 g of used newspaper (absolute dry weight) was previously cut into small pieces of about 3 cm square, and then a non-formalin type crosslinking agent (trade name: Sumitex NF-500K, manufactured by Sumitomo Chemical Co., Ltd.) and its An aqueous solution 10 containing 5 g and 2 g of a cross-linking aid (trade name: Sumitex ACCELATOR MX, manufactured by Sumitomo Chemical Co., Ltd.)
0 g was added and mixed well. The used newspaper impregnated with the cross-linking agent is placed in a 1-liter double-arm kneader (model: S1-
1, Moriyama Seisakusho), 6 arms each at room temperature
The rotation was performed at 0 rpm and 100 rpm, and a kneading treatment was performed for 40 minutes. Next, the used newspaper that had been kneaded was placed in a Warburg blender in a wet state and fibrillated. Further, the fiber was taken out of the bag, put in a stainless steel vat, and heated in a blow dryer at 150 ° C. for 30 minutes to complete the crosslinking reaction.
A cross-linked curled used newspaper was obtained. When the freeness of this waste paper fiber was measured, it was 720 ml. Crosslinked curled used newspaper 7 obtained as described above
0 parts, 5 parts of the fine fibers used in Example 1, and a fiber length of 0.1 part.
9 mm polyethylene fiber (trade name: SWP, E-40)
0, manufactured by Mitsui Chemicals, Inc.)
The raw material slurry was adjusted so that The freeness of these three types of mixed fibers was 689 ml. In the slurry tank, the forming container 10 is sunk with the open surface of the container facing upward, and as shown in FIG. Thickness 4
A 1 mm molded article was formed. Then, with the vacuum pump removed from the lower part and the air flow meter attached, as shown in FIG. 2 [pressing and molding lightly with a press upper die 17 having an uneven bottom surface and a large number of small holes 18 in the bottom surface. After smoothing the surface of the product, the pressure was increased from the hot air inlet 19 of the upper mold 17 by a compressor at a pressure of 4 kg / cm ² ,
80 ° C. hot air was blown in) to dry the molded body. The time required for complete drying was 3.9 minutes.
The flow rate of hot air immediately before drying was 7.8 liters / cm ^2.
Minutes. When the physical properties of the obtained molded body were measured,
The thickness was 41 mm and the density was 0.13 g / cm ³ . Next, as shown in FIG. 3, [while hot air is further blown into the dried molded product from the hot air inlet 19 to melt the polyethylene fiber, the molded product is strongly compressed by the press upper die 17 to increase the density of the molded product]. A final molded product 20 having a thickness of 10 mm and a density of 0.53 g / cm ³ was obtained.

As shown in Examples 1 and 2, a raw material having an appropriate freeness was selected, and hot air was flown in the deposition layer at a flow rate of 2 liters / cm ² · min or more to efficiently form the material. The body can be dried and further compacted into a high density compact.

[0041]

As described above, according to the present invention, a slurry is poured into a mold having a large number of small holes for dewatering, and fine components that do not pass through the small holes in the slurry are deposited to form a molded product. When producing a molded article obtained by drying the molded article in or out of the mold, drying is performed under the condition that the heating air flows through the deposition layer at a flow rate of 2 liters / cm ² · min or more, Since the density is increased by the pressure treatment, a molded product with good production efficiency and high strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of the present invention, and shows a state in which a wet deposition layer is thickly deposited on a lower mold of a molding container.

FIG. 2 shows a state in which the upper die 17 of a press is superimposed on the lower die 12 on which the deposited layer in the wet state is formed as shown in FIG. 1 to make the surface of the deposited layer smooth, and then hot air is sent to dry the layer. It is sectional drawing.

FIG. 3 is a cross-sectional view showing a state in which hot air is sent from a hot air injection port to the molded product dried in FIG.

FIG. 4 is a cross-sectional view of the final molded product 20.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Forming container 11, 18 Small hole for dehydration 12 Lower mold 13 Suction chamber 14 Suction port 15 Water drop 16 Wet state deposition layer 17 Press upper mold 19 Hot air injection port 20 Final molded body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Ishikawa 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Shinonome Research Center (72) Inventor Shunsuke Shioi 4-7-1 Ginza, Chuo-ku, Tokyo No. 5 Inside Oji Paper Co., Ltd. (72) Inventor Hiroshi Iwasaki 6-4, Sotokanda, Chiyoda-ku, Tokyo F-term inside Oji Bag Co., Ltd. 4L055 AA11 AC09 AF09 AF16 AF44 AF46 AG46 AG59 AG63 AG77 AG82 AG96 AH23 AH37 AH50 BF07 BF08 EA05 EA25 EA26 FA13 FA19 FA20 FA22 FA30

Claims (6)

[Claims] The Canadian Standard Freeness (CSF) is 55
Using a slurry composed of 0 ml or more of the composition, water, which is a medium of the slurry, is removed from the pores of the mold having a large number of pores, thereby allowing the pores of the slurry to pass through the pores of the slurry. The molded article is deposited to form a molded article, and then the molded article in a wet state is dried in a mold or outside the mold under the condition that heated air flows at a flow rate of 2 liter / cm ² min or more in the deposited layer. A method for producing a concavo-convex molded body, wherein the density is increased to twice or more the density before pressurization by applying a pressure treatment. 2. The method according to claim 1, wherein a heat treatment is performed during or after the pressure treatment. 3. The method according to claim 1, wherein the slurry composition contains a heat-fusible component. 4. The method according to claim 1, wherein a main component of the slurry composition is a cellulosic fiber. 5. The method according to claim 4, wherein the cellulosic fibers are used paper fibers that have been subjected to at least one of water repellency, water resistance, and curing. 6. The method according to claim 1, wherein a main component of the slurry composition is a cellulosic coarse powder.