JP2000119999A - Low density article using waste paper as raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low density article having a low density, excellent cushioning property and producibility by using waste paper as a raw material. SOLUTION: This low density article having 0.02-0.30 g/cm3 is obtained by dehydrating and drying a slurry mainly composed of fibers having >=550 ml Canadian standard freeness(CSF) and obtained by opening waste paper having <=20 sec Oken type drainage speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a low-density body made of waste paper and having excellent low-density, buffering properties and productivity.

[0002]

2. Description of the Related Art Styrofoam conventionally used as a cushioning material has excellent characteristics such as excellent shock absorption, easy processing into an arbitrary shape, low cost, light weight, and good appearance. have. 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. In other words, it has been pointed out that in the case of incineration after use, damage to the furnace and generation of toxic gas due to generation of high temperature. 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, pulp has been manufactured using a raw material, which is given a cushioning property and strength by devising its shape. Pulp molds that can be easily processed have attracted attention and are increasingly used as substitutes for styrene. In particular, waste paper such as newspapers and magazines is discharged in large quantities in recent years, but due to the performance and poor appearance of the fibers obtained by defibration, the range of use is narrow, demand is not growing, and inventory is in excess. Pulp molds used as raw materials are ideal when viewed from environmental issues.

[0004]

However, the pulp in the slurry is deposited on a mold having a large number of small holes while sucking and dewatering, and then dried to obtain a molded product. When waste paper fiber is formed as a raw material, as the accumulation of pulp in the mold progresses, the adhesion between the pulp fibers progresses, resulting in poor water drainage. Time is required, and unless the production efficiency is neglected,
m could not be obtained. For this reason, the obtained product was inferior in buffering properties, was not sufficiently strong, and lacked suitability as a packaging material. An object of the present invention is to provide a low-density body that is made of waste paper and has excellent low-density, buffering properties, and productivity.

[0005]

In view of the above situation, the present inventors have conducted intensive studies on molded articles made of waste paper, which have excellent low density and cushioning properties, and have high productivity. By using certain waste paper fibers as raw materials,
They have found that this can be achieved and have completed the present invention. That is, the present invention provides a Canadian Standard Freeness (CSF) obtained by fibrillating waste paper having a dewatering speed value of 20 seconds or less, a Canadian Standard Freeness (CSF) slurry containing 550 ml or more as a main raw material is dewatered and dried. And the density is 0.02-
It is a low-density body characterized by being 0.30 g / cm ³ . By the way, the Oken type dehydration rate value is 400 m in length, which is used as the bottom plate of 80 mesh stainless steel wire.
m, 24.3 g (dry weight) of fibers obtained by dry-fibrillating paper into a single fiber in an acrylic resin cylindrical container having an inner diameter of 83 mmφ, and a solid content concentration of 1 prepared by well stirring and dispersing in 1596 cc of water. It is expressed by the time (second) until the liquid surface reaches a height of 100 mm from the bottom plate after putting a 0.5% slurry after holding it for 30 minutes after the preparation and sucking and dewatering it from the bottom at 350 mHg. In the present invention, it is preferable that the waste paper is a waste paper containing 3% by weight or more of a curable, water-repellent, or water-resistant component based on the dry solid content based on the pulp. Further, the thickness of the low-density body is preferably 10 mm or more. Further, it is preferable that other fibers are further added to the slurry. In particular, the other fiber is preferably a fiber having a bond reinforcing factor of 0.15 or more, or a fiber having a Canadian Standard Freeness (CSF) of 550 ml or more. Further, it is preferable that a non-fiber material of 550 ml or more of Canadian Standard Freeness (CSF) is added to the slurry.

[0006] The first cause of the success of the present invention is to use, as a raw material, a fiber obtained by defibrating waste paper having an Oken-type dewatering speed value of 20 seconds or less, which is excellent in dewatering property at the time of forming a thick material. By
The point is that it has been found that the adhesion between fibers during suction and dehydration is suppressed, and the resulting molded article has a lower density than expected. The second cause is that the following merits arise when a molded product having a sufficient thickness and excellent cushioning properties is efficiently obtained from the raw material. A molded article applicable to heavy objects is obtained. A molded article exhibiting excellent shock-absorbing properties against the second or subsequent drop impact is obtained. In addition, since there is no need to devise structural measures such as the rib structure, complicated molds such as the conventional pulp molding method are not required, and the time required for mold design and manufacturing can be greatly reduced. The mold can be manufactured at low cost. Since it can be manufactured with an inexpensive mold, the productivity can be increased by preparing many molds, and the production cost can be suppressed to a relatively low production cost even for a small lot and a wide variety of products.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As used paper used in the present invention and having an Oken-type dehydration rate of 20 seconds or less, for example, pulp treated with a curing agent, a water-proofing agent, a water-repellent agent, etc. is used as a raw material. A sheet obtained by applying or impregnating a liquid containing a curing agent, a water-proofing agent, a water-repellent agent, etc. to the used paper and base paper of the sheet obtained by laminating a film on the used paper and paper. Waste paper of a sheet, waste paper of a sheet obtained by mixing pulp and a synthetic polymer fiber, and the like are included. In the present invention, besides, a non-woven fabric such as a nonwoven fabric having a Oken-type dehydration rate value of 20 seconds or less can be used as a raw material.

Examples of the curing agent include aldehydes (formaldehyde, dialdehydes such as glyoxal, glutaraldehyde, etc.), N-hydroxymethyl compounds (formaldehyde and urea, cyclic urea, triazine, amide, acrylamide, carbamate, etc.). Reaction products such as dimethylol urea, dimethylol ethylene urea, trimethylol melamine, N-methylolamide, N-methylolacrylamide, ethylene-b
is- (N-methylol carbamate and the like), divinyl compound (divinyl sulfone and the like), halogen compound (dichloroacetone, 1,3-dichloropropanol-2,
Chloromuconic acid, cyanuric chloride, dichloroacetic acid, etc.),
Epoxy compounds (halohydrins such as epichlorohydrin, polyepoxides such as butadiene diepoxide, polyglycidyl ether, etc.), aziridinyl compounds (Tr
is- (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, anhydride) Maleic acid, succinic anhydride, etc.), polyvalent isocyanates (hexamethylene diisocyanate, 2,
4-tolylene diisocyanate), and quaternary ammonium salts (such as quaternary ammonium derivatives of Bis-chloromethyl ether).

As the water repellent, for example, acid chloride type water repellent, isocyanate type water repellent, 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 compound type water repellent, titanium containing compound type water repellent, zirconium containing compound type water repellent, fluorine compound type water repellent Agents, silicon compound type water repellents and the like. Other water repellents include 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.

As the water-proofing agent, the above-mentioned cellulose-reactive chemicals and waxes can be used, and further, water-insoluble resins can be used. Examples thereof include rosin-based resins, terpene-based resins, natural rubber, synthetic rubber, thermoplastic synthetic resins, thermosetting resins, and the like. Examples of the thermoplastic resin include a hydrocarbon resin, an acrylic resin, a vinyl acetate resin, a vinyl chloride resin, a polyamide resin, and a polyester resin. Examples of the thermosetting resin include an epoxy resin, a urethane resin, a melamine resin, a urea resin, a formalin resin, and a phenol resin.

Examples of the film used for lamination include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, aromatic polyester, aliphatic polyester, polylactic acid, nylon, polystyrene, polycarbonate, polyvinyl alcohol, and ethylene vinyl acetate. Coalescence, saponified ethylene-vinyl acetate copolymer, aluminum vacuum-deposited film, and the like.

Examples of the synthetic polymer fiber include aromatic polyester fiber, aliphatic polyester fiber, polyethylene fiber, polypropylene fiber, polyethylene-polypropylene sheath core fiber, polyacrylonitrile fiber, acrylic fiber, polyamide fiber and the like.

The curable or water-repellent or water-resistant component such as the above-mentioned curing agent, water-proofing agent, water-repellent agent, film, synthetic polymer fiber, etc. is added to the pulp at 3% by weight per solid content.
The waste paper fibers having the above are preferred.
Specific examples thereof include water-resistant paper, water-resistant cardboard, wax paper, resin-processed paper, milk carton paper, paper cup paper, release paper for adhesive paper of a laminate type, shopping back paper, and the like. Among the above-mentioned curable, water-repellent, or water-resistant components, those which are degradable, particularly biodegradable, are preferable in terms of environment.

The used paper used in the present invention has a sufficient curing or water-repellent or water-resistant component such as a curing agent, a water-proofing agent, a water-repellent agent, a film, or a synthetic polymer fiber to react with the pulp fiber. Heat treatment or pressurization treatment is also included in order to improve the quality of the pulp fiber, or to promote penetration into the pulp fiber, or to improve the familiarity with the pulp fiber.

The defibration of the used paper can be performed by a dry method or a wet method. Examples of machines used for defibration include, for example, pocket grinders, chain grinders, grinders such as ring grinders, single disc refiners, double disc refiners, refiners such as conical type refiners, other beating machines such as beaters, blenders, and the like. Stirrers such as deflakers, wood chip defibration machines such as defibrators and defibrizers, and flash-dried pulp manufacturing facilities such as hammer mills, pin mills, and fluffers. In the present invention, dry defibration is preferred in terms of low density.
Among the defibration machines used for dry defibration, hammer mills,
Pin mills and disc refiners are preferred. Specific examples include a fiber riser manufactured by Sumikura Kogyo / Nishi Nippon R & D Co., Ltd., an impact mill manufactured by Dalton, a free crusher manufactured by Nara Machinery Works, a hammer mill, a cage mill, and an MK hammer mill manufactured by Masuko Sangyo.

As a means for improving the low density property, a mechanical force (and, if necessary, heat) is applied to the waste paper fiber to deform the fiber into a curl shape, or to granulate the fiber into a lump. It is valid. Further, as described in Japanese Patent Application No. 10-32920, it is also effective to further treat the used paper fiber with the above-mentioned curing agent, water-proofing agent and water-repellent agent.

The slurry of the present invention is usually prepared batchwise or continuously using an apparatus having a stirrer. When dry defibrated fibers are used, the longer the wetting time, the lower the stiffness of the fibers, and the lower the density, the cushioning, and the productivity. It is preferably used for molding. In particular, it is preferably within one hour.
In addition, the continuous preparation method in which the slurry preparation is performed in conjunction with the molding step is preferable because the wet time is always kept almost constant and the quality of the low-density body is easily stabilized. Water is usually used as a dispersion medium used for forming a slurry, but a mixture of water and an alcohol may be used. When a mixed solution of water and alcohol is used, there are advantages such as good drying properties and increased productivity. Heating the medium also 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 0.03 to 10% by weight, but preferably in the range of 0.03 to 5% by weight in terms of the dispersed state.

The Canadian Standard Freeness (CSF) obtained by defibrating waste paper having a Oken-type dewatering speed value of 20 seconds or less is 55.
The desired low-density body can be obtained with only 0 ml or more of the fiber alone, but if improvement in interlaminar strength or low-density is required, take measures to add other materials to the slurry composition Can be done. As a material having a large effect of improving the low-density interlayer strength, a fibrous material having a bond reinforcing factor of 0.15 or more can be given. The one that has the great effect of improving the low density property is Canadian Standard Freeness (CSF) 550ml.
The above-mentioned fibrous materials and non-fibrous materials are mentioned. As the fiber material having a bond reinforcing factor of 0.15 or more, a natural polymer fiber, a synthetic polymer fiber, a semi-synthetic polymer fiber, or a material obtained by treating them and having a bond reinforcing factor of 0.15 or more is used. Things.

Examples of the natural polymer fiber include unbleached or bleached chemical pulp obtained by converting softwood or hardwood into kraft pulping, sulfite pulping, alkali pulping, or the like, or GP, RMP, TMP, CTMP or the like. Examples thereof include mechanical fibers, cellulosic fibers such as cotton pulp and linter pulp, protein fibers such as wool, silk, and collagen fibers, and complex sugar chain fibers such as chitin / chitosan fibers and alginic acid fibers. As the synthetic polymer fiber, for example, aromatic polyester fiber, aliphatic polyester fiber, polyethylene fiber, polypropylene fiber,
Polyethylene-polypropylene sheath core fiber, polyacrylonitrile fiber, acrylic fiber, polyamide fiber, and the like are included. Examples of the semi-synthetic polymer fiber include a fiber obtained by chemically modifying a natural product, such as an acetylcellulose fiber. Incidentally, a recycled product such as waste paper can also be used as the fibrous material.

Among them, those having biodegradability such as cellulosic fibers, aliphatic polyester fibers, and acetylcellulose fibers are preferably used.
Specific examples include fibers such as Bionole (Showa Kobunshi), Lacia (Mitsui Chemicals), Lunar ZT (Nippon Shokubai), and general-purpose pulp. Above all, from the viewpoints of stability of raw material supply and cost, cellulose fibers or those obtained by treating the same are preferred.

Among fibers having a bond reinforcing factor of 0.15 or more, fine fibers obtained by subjecting fibers to mechanical treatment are more preferable. Those subjected to mechanical treatment tend to have a branched shape, and the effect of increasing the interlayer strength is extremely large.
Above all, from the size of the effect of increasing the interlayer strength and the ease of manufacture, coniferous and hardwood are made into kraft pulp,
Unbleached or bleached chemical pulp obtained by sulfite pulping, alkali pulping, etc., GP, RMP, TM
Mechanical pulp such as P, CTMP, or cotton pulp,
A cellulosic fiber known as a papermaking raw material such as linter pulp or waste paper pulp is mixed with a medium stirring mill (JP-A-4-181).
No. 86), a vibration mill (Japanese Patent Application Laid-Open No. 6-10286), a high-pressure homogenizer, a colloid mill, a beating machine and the like obtained by wet mechanical treatment are particularly preferable. The size of the fine fibers is not particularly limited, but usually, those having a number average fiber length in the range of 0.01 to 0.80 mm and a fiber width in the range of 0.1 to 30 μm are preferably used.

The binding enhancement factor (BF) referred to in the present invention.
Is calculated by (E2−E1) / E1. However, E1
Is a mixture of bleached hardwood kraft pulp 50% by weight and softwood bleached kraft pulp 50% by weight to form an aqueous slurry,
After beaten to 500 ml of Canadian Standard Freeness (CSF), dewatered and air-dried with a hand making machine according to JIS-P-8209 to produce a sheet having a basis weight of 60 g / m ² ,
The figure shows the ultrasonic elastic modulus measured after heat treatment at 30 ° C. for 2 minutes and humidity control at 20 ° C. and 65% RH. E2 indicates the ultrasonic elastic modulus when an aqueous slurry was prepared by replacing 50% of the pulp fibers with fine fibers, and a sheet was prepared and measured in the same manner as in the measurement of E1.

The amount of the fibrous material having a bond reinforcing factor of 0.15 or more in the composition is not particularly limited, but is usually in the range of 1 to 40% by dry weight with respect to the composition.

When fibers having a bond reinforcing factor of less than 0.15 are used in the present invention, the effect of improving the interlaminar strength is weak when blended in a small amount, and the interlaminar strength is increased but the low density is slightly inferior when blended in a large amount. Become. However, it can be blended depending on the application.

The fiber material having a large effect of improving the low density property and having a Canadian Standard Freeness (CSF) of 550 ml or more can be obtained by treating natural polymer fibers, synthetic polymer fibers, semi-synthetic polymer fibers, or those. And 550 ml or more of Canadian Standard Freeness (CSF).

The natural polymer fibers include, for example, unbleached or bleached chemical pulp obtained by kraft pulping, sulfite pulping, alkali pulping of coniferous or hardwood, or GP, RMP, TMP, CTMP or the like. Cellulosic fibers such as mechanical pulp, cotton pulp, linter pulp, liquid ammonia treated pulp, mercerized pulp, pulp subjected to at least one of water repellency, water resistance, hardening, and curling treatments, wool And protein fibers such as silk fibers and collagen fibers, and complex sugar chain fibers such as chitin / chitosan fibers and alginate fibers. Examples of the synthetic polymer fiber include an aromatic polyester fiber, an aliphatic polyester fiber, a polyethylene fiber, a polypropylene fiber, a polyethylene-polypropylene sheath core fiber, a polyacrylonitrile fiber, an acrylic fiber, and a polyamide fiber. Examples of the semi-synthetic polymer fiber include a fiber obtained by chemically modifying a natural product, such as an acetylcellulose fiber. Incidentally, a recycled product can be used as the fiber cord material.

Among them, those having biodegradability such as cellulosic fibers, aliphatic polyester fibers, and acetylcellulose fibers are preferably used.
Specific examples include fibers such as Bionole (Showa Kobunshi), Lacia (Mitsui Chemicals), Lunar ZT (Nippon Shokubai), and general-purpose pulp. Above all, from the viewpoints of stability of raw material supply and cost, cellulose fibers or those obtained by treating the same are preferred. From the viewpoint of the effect of improving the low density property, curled fibers obtained by subjecting fibers to a deformation treatment are preferable, and examples thereof include HBA-FF, NHB405, and NHB416 (trade names, manufactured by Warehauser, USA).

Canadian Standard Freeness (CSF) 550 m
The amount of the fibrous material of at least 1 in the composition is not particularly limited, but is usually in the range of 5 to 60% by dry weight with respect to the composition.

550m Canadian Standard Freeness (CSF)
l or more non-fibrous materials include, for example, natural organic materials such as cellulosic coarse powder, sawdust, chaff, soybean meal, etc. obtained by coarsely pulverizing cellulosic materials such as wood, bagasse, rice straw, and coconut shell fibers. Synthetic organic polymers such as coarse polymer powder, synthetic resin beads such as polyethylene and polystyrene, coarsely crushed foamed resin such as expanded polystyrene, crushed old tires, etc. 550ml of Canadian Standard Freeness (CSF)
Those showing the above are mentioned. Among them, coarsely ground natural organic polymer coarse powder and acetyl cellulose are preferable because they have biodegradability and are environmentally friendly. Above all, a cellulose-based coarse powder obtained by mechanically defibrating wood and used as a raw material for fiberboard is particularly excellent in the effect of improving the low-density property, and the raw material is easily procured. Examples of the defibration method include those known in the fiberboard industry, such as the asplund method. Among them, those that are defibrated at a high temperature of 110 ° C or more, particularly 130 ° C or more, are better than those processed at a lower temperature. This is preferable because it tends to have high rigidity, and therefore tends to have excellent effects of improving low density and cushioning property. In addition, as a means for increasing the rigidity, a method of performing a crosslinking reaction treatment, a hydrophobic treatment, and a surface resin treatment after the defibration treatment of the wood chips is effective. Further, the above-mentioned pulverized product or a product obtained by further curling the processed product with a kneader or the like is particularly preferable because the effect of improving the buffering property is more remarkable. The amount of the above components in the composition is not limited to this range, but is usually in the range of 10 to 60% by dry weight with respect to the composition.

Incidentally, the Canadian standard freeness is based on JIS.
It is a value indicating the drainage of pulp usually specified in -P-8121. In the present invention, the drainage of the non-fibrous material was determined based on the same measuring method.

The slurry composition may further contain, as necessary, ordinary waste paper fiber, a paper strength enhancer, a water-proofing agent, a water-repellent,
Foamable microcapsules, inorganic fibers, metal fibers, sizing agents, dyes, pigments, retention aids, fillers, pH regulators, slime control agents, thickeners, preservatives, fungicides, antibacterial agents, flame retardants, Select preservatives, rodenticides, insecticides, moisturizers, fresheners, deoxidizers, microcapsules, foaming agents, surfactants, electromagnetic shielding materials, antistatic agents, rust inhibitors, fragrances, deodorants, etc. Can be blended. These may be used in combination of two or more.

Examples of ordinary waste paper fibers include used newspapers, books, magazines, telephone directories, catalogs, high-quality paper, and the like.
Packaging boxes, cardboard boxes, pulp molds, paper cushioning materials,
Alternatively, a fiber obtained by fibrillating cut or waste paper discharged from a factory or business site such as papermaking, printing, bookbinding, boxmaking, or corrugated cardboard in a dry or wet process is exemplified.

As the composition used for forming the slurry, those having a Canadian standard freeness (CSF) of 550 ml or more are preferred because of their excellent low-density productivity and low-density.

Hereinafter, the production of a molded article in which the effects of the present invention are particularly remarkable will be mainly described. As a molding die used for the production of a molded product, a normal pulp molding die can be used as it is, but when a block-shaped molded product having better cushioning properties is required, a large number of A deep-bottomed container having a small hole, for example, a cylindrical container such as a cylinder or a square tube, or a split container is usually used. (Hereinafter, in the present invention, the mold is referred to as a mold container)

The small holes formed in the molding container may have any shape such as a circle, an ellipse, a square, and a rectangle. The size of the small holes may be such that the pulp fiber hardly leaks, and usually has a diameter or a side of 30 μm to 3 μm.
A circular or square shape in the range of mm is used, but is not particularly limited in the present invention. Usually, when the pulp fiber is large, a large one is used, and when it is small, a small one is used. It is also possible to use a molding container wall having relatively large holes, such as a mold used for pulp molding, with a fine mesh attached to the wall. Also, the size of the small holes can be changed in each part 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. In consideration of the dehydration efficiency and the like, it is preferable that small holes are present in a portion of 20% or more of the wall of the molding container, more preferably 35% or more. The number of parts to in pores small pores there is preferably made present one or more per 1 cm ^2, more preferably 4 or more per 1 cm ^2.

The slurry is injected into the molding container by injecting the slurry from the opening into the molding container with the opening facing upward by a pump. The slurry is immersed in a slurry tank with the opening facing downward as in a normal pulp mold. By sucking more, the slurry is sucked into the molding container from the downward opening port, suction is performed while sinking the molding container into the slurry tank with the opening port facing upward, and the slurry is sucked into the molding container from the opening port. You can take the method. As a method for removing water as a 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 wet molded product formed in the molding container by removing the water of the dispersion medium from the small holes is thereafter taken out of the container or taken out of the container and dried. In the case of drying in a container, a molded product having high dimensional accuracy can be obtained, but the productivity is poor. On the other hand, in the case of drying outside the container, the dimensional accuracy is slightly inferior, but the productivity is excellent. As an intermediate proposal, a method may be employed in which after drying in a container is performed halfway, the container is taken out and dried outside the container.

As a drying method, for example, known methods such as hot air drying, infrared drying and microwave drying can be used alone or in combination. Heating steam can be used instead of hot air for drying halfway. Among them, the hot air drying method is preferred because the apparatus is inexpensive and the molded product is less likely to burn. Above all, air drying in which the flow of air in the inter-fiber voids is improved by injecting heated air (gas) into a wet molded product or by suction while inserting heated air from the opposite side of the molded product,
Drying is quick and the production efficiency of the molded product is extremely high, which is particularly preferable. In hot air drying, hot air in a temperature range of usually 80 to 400 ° C. is used. The air flow rate of air drying is 2
Liter / cm ² min or more is preferable in terms of drying efficiency,
Particularly preferred is 5 liters / cm ² · min or more. This through drying is particularly effective when drying a molded product having a thickness of 10 mm or more, particularly 40 mm or more. In order to increase the drying speed of the molded body, the surface of the molded body is intentionally made uneven to increase the surface area, or a hole is formed in the molded body to penetrate or non-penetrate so that air can easily enter the interfiber space. Is also effective. As a good drying method for a molded body having a portion having a thickness of 40 mm or more, specifically, a molded body having a thickness of 30 m
m or more, non-through holes are provided at intervals of 10 to 30 mm, and hot air at a temperature of 200 to 300 ° C. is
A method of injecting at a pressure of g / cm ² can be given. As a method of intentionally forming irregularities on the surface of the molded body, a method of providing an irregular pattern on a molding die is effective, and a method of providing a through hole or a non-through hole in a molded body is effective using a water flow such as a water jet. It is. In addition, a method in which the forming container is heated before pouring the slurry has an effect of increasing the drying speed.

Hereinafter, the molding method used in the present invention will be described in detail with reference to the drawings in order to show the method more specifically, but the present invention is not limited thereto.

1 to 4 are sectional views showing one molding method used in the present invention. The molding container 10 is shown in FIG.
As shown in the figure, a double-walled container having a cylindrical shape with an open top,
The inner wall has a large number of small holes 11 for dehydration, the inner wall has a convex lower mold 12 having a step at the inner periphery of the bottom, and a suction chamber 13 is formed by inner and outer double walls. Has a suction port 1
4 are attached. Although the shape of the lower mold 12 is schematically illustrated as a simple one with a stepped portion, the shape of the unevenness may be more complicated according to the shape of the product protected by the cushioning material.

FIG. 1 shows the slurry 1 from the upper guide 15.
6 shows a state in which the fibers are deposited so as to swell on the open surface of the container by suction dehydration from the lower suction port 14 while injecting 6, and the filling into the container 10 is completed. Reference numeral 17 denotes water droplets that have oozed out by suction, and reference numeral 18 denotes a filling of wet fibers.

FIG. 2 shows a state in which an unnecessary portion raised and deposited on the open surface of the molding container of FIG. The cutting is performed while moving the water jet nozzle. FIG. 3 shows a press machine 20 having a flat bottom and a large number of small holes 21 on the bottom, which is lightly compressed to make the surface smooth, and then hot air is sent from a hot air port 22 of the upper mold 20 to be dried. It shows the state where it is. At this time, if suction is performed from the suction port 14, drying proceeds more efficiently. FIG. 4 shows a final molded product 23 obtained by taking out from the molding container 10 after drying. By the way,
If the bottom of the press upper die 20 of FIG. 3 is used in a special shape, a molded product having a more complicated surface shape can be obtained.

The molding method is not limited to the above-mentioned method, and the water in the split mold is gradually extruded while the slurry is poured under pressure into a split mold filled with water, and the split mold is filled with fibers. Then, a method of blowing out hot air from a pipe inserted into the center of the split mold to dry the split mold is also effective.

[0044] The molded article may contain a paper strength enhancer, a water-proofing agent, a water repellent, a dye, a pigment, a preservative, a fungicide, an antibacterial agent, a flame retardant, a rodenticide, an insect repellent, a freshness-retaining agent, a deoxidizer, As a method of incorporating an electromagnetic shielding material, an antistatic agent, a rust preventive, an aromatic agent, a deodorant, etc., other than the internal addition method of adding and mixing these in a slurry as described above, the surface of the molded body may be prepared after manufacturing. A coating method, that is, an external addition method can also be used. Means such as impregnation, brushing, and spraying can be used for this surface application. Of course, both internal and external additions may be used. In the case of external addition, the above fine fibers can also be used. The external addition method has a feature that more additive components can be distributed on the surface than the internal addition method. In addition, high quality paper, cellophane paper, water resistant paper, oil resistant paper, evaporated paper, coated paper, synthetic paper, nonwoven fabric, cloth,
Synthetic film, metal foil, wood board, synthetic resin board, glass board,
Other materials, such as a metal plate, can also be used by being completely or partially pasted. Also, cardboard, paperboard, board, synthetic resin board,
It can also be used by sandwiching, affixing, fitting, and the like on a processed product such as a metal plate or a box. Further, the obtained molded bodies can be bonded together. As a means for providing a film layer on the surface of the molded product, shrink packaging technology can be used. As materials used in combination, environmentally friendly materials such as biodegradable materials are preferable. In addition, the molded body may be subjected to processing such as cutting and printing.

The molded article thus obtained is characterized by its low density, cushioning property, heat insulation, sound insulation, moisture absorption, biodegradability, etc. It can be widely applied to the field. In addition, it can be used in the field of filters by taking advantage of air permeability. In addition, fields such as mannequins are also promising because of their low density.

The most remarkable effect of the present invention is a molded product, but it is also effective for sheets and boards.
This is briefly described below. When a sheet is obtained by the present invention, the sheet can be produced using a paper machine known in the papermaking industry such as a round paper machine, a fourdrinier paper machine, an inclined wire paper machine, and a twin wire paper machine. The thickness of the sheet is usually 30 μm to 5 m
m. The density of the obtained sheet is affected by the raw material and composition of the slurry composition. In addition, the pressure applied to the sheet during the production stage is important. It is necessary to keep the dewatering pressure of the wire part low and the press pressure of the wet press part low. The press linear pressure at that time is 30 kgf / cm or less, and in particular 20 kf / cm.
gf / cm or less is preferable. For the drying step, any method known in the art can be used. Among them, hot-air ventilation drying in which a heated air jet is blown on the paper surface is preferable because the drying speed is increased.

The obtained low-density sheet takes advantage of its features such as light weight, heat insulating properties, cushioning properties, air permeability, etc., and is unprocessed, or is subjected to post-processing such as surface coating or impregnation to produce high quality paper, fine coated paper. Base paper, art paper, coated paper, base paper for thermal recording, base paper for thermal transfer receiving paper, base paper for sublimation transfer receiving paper, base paper for pressure-sensitive copying paper,
Base paper for paper cups, base paper for lamination, base paper for vapor deposition,
It can be used as electrophotographic copying paper, wrapping paper, heat insulating paper, filters, fancy paper and the like. In the field where surface smoothness, stiffness and whiteness are required, it is effective to use a Yankee machine, or to make a multi-layer papermaking using a fiber having a higher surface smoothness or a fiber having a higher whiteness. is there.
Also, an ultra-lightweight coated paper can be obtained by applying a hollow plastic pigment-containing paint or a bubble-containing paint on the low-density sheet. In addition, other materials can be attached and used according to the purpose.

The board usually has a thickness of 5 mm to several cm, and is a paper machine known in the paper industry, a machine known in the board industry, and a relative rotary twin mesh, which can make thick materials such as an inclined wire paper machine and a twin wire paper machine. It can be manufactured by an apparatus having a cylinder partially. The density of the resulting board is affected by the raw material and formulation of the slurry composition,
Besides that, the pressure on the board during the manufacturing stage is important,
In order to keep the density as low as possible, the degree of vacuum of the suction roll is suppressed to keep the dehydration pressure of the wire part low.
Alternatively, it is necessary to keep the press pressure of the wet press part low. The press linear pressure at that time is 30 kgf /
cm or less, especially 20 kgf / cm or less.
Water cutting is effective for cutting off the edge or cutting the wafer into a single sheet. For the drying step, any method known in the art can be used. Among them, a method of injecting heated air (gas) into a wet board, or suctioning while injecting heated air from the opposite side of the board, is used. The through-flow drying in which the air flow in the inter-fiber voids is improved is particularly preferable because the drying is quick and the production efficiency of the molded product is extremely high. 80-400 for hot air drying
Hot air in the temperature range of ° C is used. The amount of ventilation in the through-air drying is preferably 2 liters / cm ² · min or more in the early stage of drying from the viewpoint of drying efficiency, and particularly preferably 5 liters / cm ² · min or more. This through drying is particularly effective when drying a board having a thickness of 10 mm or more, especially 40 mm or more. In order to increase the drying speed of the board, it is also effective to intentionally make unevenness on the surface of the board to increase the surface area, or to make a hole that penetrates or non-penetrates the board to make it easier for air to enter the interfiber space. is there. As a method of providing the board with irregularities or through holes or non-through holes, it is effective to use a device having an irregular wire.

The obtained low-density board utilizes the features such as light weight, heat insulating property, cushioning property, soundproofing property, moisture absorbing property, air permeability, etc., and can be used as it is, unprocessed, or bonded, surface coated, impregnated or cut. It can be used in fields where foamed resins have been used so far, for example, building materials, packaging materials, automotive ceiling materials, etc., and filters.

[0050]

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 “%” indicate “parts by weight” and “% by weight” unless otherwise specified.

<Example> A polyethylene laminate type release paper for adhesive paper obtained by sequentially laminating a 13 μm polyethylene layer and a 0.5 g / m ² silicone layer on 74 g high quality paper was used as a fiber riser (Sakura Kogyo / Nishi Nippon Technology Co., Ltd.). It was defibrated by a dry defibrillator (developed by R & D) to obtain used paper fibers. The Oken-type dewatering rate value of this waste paper was measured to be 10 seconds. Further, the Canadian Standard Freeness (CSF) of this waste paper fiber was measured and found to be 650 ml or more. Next, a raw material slurry was prepared by dispersing the waste paper fiber in water to have a solid content concentration of 2%, and the slurry was charged into a tank.
This is a molding machine equipped with a disk-shaped female mold (suction from the bottom only) with an inner diameter of 200 mm and a depth of 20 mm.
Under the condition of 00 mHg, the fibers were deposited by suction for 8 seconds,
Thereafter, the portion protruding from the female mold was cut with a water jet to obtain a wet molded product. Subsequently, the molded product was dried by sending hot air at 150 ° C. pressurized to 1 kg / cm ² from the opening of the female mold. When the physical properties of the obtained molded body were measured, the density was 0.11 g / cm ³ .

[0052]

As described above, according to the present invention, a slurry mainly composed of fibers having a Canadian standard freeness (CSF) of 550 ml or more, obtained by defibrating waste paper having an Oken-type dewatering rate of 20 seconds or less, is used. Since it is molded by using, a material having a low density and excellent cushioning properties can be obtained efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a molding container used for producing a molded article of the present invention, in which a solid content of a slurry is deposited on the molding container.

FIG. 2 is a cross-sectional view showing a state in which unnecessary portions accumulated on an open surface of the molding container of FIG. 1 are cut.

FIG. 3 is a cross-sectional view illustrating a state where a wet deposit in FIG. 2 is dried.

FIG. 4 is a cross-sectional view of the final product obtained according to FIG.

[Explanation of symbols]

10: Mold (molding container), 11: Small hole, 12: Lower mold,
13: suction chamber, 14: suction port, 15: guide, 16: fiber slurry, 17: water droplet, 18: fiber deposit, 19: water jet, 20: upper die, 21: small hole,
22: hot air port, 23: final molded product

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisao Ishikawa 4-7-5 Ginza, Chuo-ku, Tokyo Oji Paper F-term (reference) 4L055 AA11 AH23 AH50 BF01 BF06 EA05 EA25 EA32 EA40 FA13 FA16 FA22 GA04 GA24

Claims (2)

[Claims] 1. Canadian Standard Freeness (CSF) obtained by defibrating waste paper whose Oken-type dewatering speed value is 20 seconds or less.
Is obtained by dehydrating and drying a slurry containing 550 ml or more of fibers as a main raw material, and having a density of 0.02 to 0.30 g.
/ Cm ³ . 2. The low-density body according to claim 1, wherein the waste paper is a waste paper containing at least 3% by weight, based on dry solid content, of pulp of a curable, water-repellent or water-resistant component.