CN112878083A

CN112878083A - Method and apparatus for producing fiber formed product, bonding material and method for producing the same

Info

Publication number: CN112878083A
Application number: CN202011334341.4A
Authority: CN
Inventors: 若林繁美
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2019-11-29
Filing date: 2020-11-25
Publication date: 2021-06-01
Also published as: JP2021085127A; US20210164162A1

Abstract

Provided are a method and an apparatus for producing a fiber formed product, a bonding material, and a method for producing the bonding material, wherein the amount of petroleum-derived materials used is reduced, and the mechanical strength and paper strength of stretching, tearing, and the like are sufficient. In the method for producing a fiber molded product, a plurality of first fibers are bonded by a bonding material, which is a mixture of a defibrated first fiber and a bonding material in which a plant-derived thermoplastic resin and a natural fiber are integrated, by heating the mixture in a mixed state.

Description

Method and apparatus for producing fiber formed product, bonding material and method for producing the same

Technical Field

The present invention relates to a method and an apparatus for producing a fiber formed product, and a bonding material and a method for producing the same.

Background

As a method for producing a fiber formed product such as paper, a method using water at all or almost no amount, which is called a dry method, is desired. For example, patent document 1 discloses an apparatus for producing a fiber formed product, the apparatus comprising: a mixing unit that mixes the first fibers with a powder that integrally includes at least natural fibers and a resin; and a bonding section that bonds the first fibers and the powder, wherein the powder has a volume average particle diameter of 3 μm or more and 50 μm or less.

In the technique disclosed in patent document 1, a regenerated sheet is produced by mixing a binding material made of a thermoplastic resin with defibrated cotton obtained by defibrating waste paper and heating the mixture under pressure. However, as the thermoplastic resin constituting the binder, a petroleum-derived resin such as polyester is used. Further, when a resin other than a petroleum-derived resin is used as a binder and applied to a fiber molded product, the mechanical strength and paper force of the fiber molded product such as stretching and tearing may be insufficient.

Patent document 1: japanese laid-open patent publication No. 2015-168255

Disclosure of Invention

In one embodiment of the method for producing a fiber molded product according to the present invention, a plurality of first fibers are bonded by a bonding material, which is a mixture of a defibrated first fiber and a bonding material in which a plant-derived thermoplastic resin and a natural fiber are integrated, by heating the mixture in a mixed state.

In the aspect of the method for producing a fiber formed product, the natural fibers may be cellulose fibers.

In any one of the above-described methods for producing a fiber molded product, the plant-derived thermoplastic resin may be one or more selected from polylactic acid, biological polyamide, polyhydroxyalkanoate, and an isosorbide-containing resin.

In any of the above-described methods for producing a fiber molded product, the mass ratio of the plant-derived thermoplastic resin to the natural fiber in the binder (plant-derived thermoplastic resin/natural fiber) may be 1/3 or more and 4/1 or less.

In any one of the above-described methods for producing a fiber molded product, the natural fibers in the binder may have an average fiber length of 0.8mm to 2.0 mm.

One embodiment of a device for producing a fiber molded product according to the present invention includes a heating section that heats a first fiber that has been defibrated, and a bonding material in which a plant-derived thermoplastic resin and a natural fiber are integrated, and bonds a plurality of the first fibers together with the bonding material.

In the above aspect of the apparatus for producing a fiber molded product, the apparatus may further include a defibering unit that performs defibering of a raw material including fibers to obtain the first fibers, and a mixing unit that mixes the first fibers and the binder.

In the above aspect of the apparatus for producing a fiber molded product, the apparatus may further include a stacking unit that stacks the first fibers and the binder mixed in the mixing unit.

In any one of the above-described apparatus for producing a fiber molded product, a mass ratio of the plant-derived thermoplastic resin to the natural fiber in the binder (plant-derived thermoplastic resin/natural fiber) may be 1/3 or more and 4/1 or less.

In any one aspect of the apparatus for producing a fiber formed product, the apparatus may further include a pressing section that presses the first fibers that have passed through the heating section and have been bonded by the bonding material.

In any one embodiment of the apparatus for producing a fiber molded product, the plant-derived thermoplastic resin may be one or more selected from the group consisting of polylactic acid, biological polyamide, polyhydroxyalkanoate, and isosorbide-containing resin.

In any one of the above-described apparatus for producing a fiber molded product, the natural fibers in the binder may have an average fiber length of 0.8mm to 2.0 mm.

In one embodiment of the bonding material according to the present invention, the plant-derived thermoplastic resin is integrated with the natural fiber.

In one embodiment of the method for producing a bonding material according to the present invention, the method includes kneading the plant-derived thermoplastic resin and the natural fiber to integrate the plant-derived thermoplastic resin and the natural fiber.

Drawings

Fig. 1 is a schematic view of a fiber-formed product manufacturing apparatus according to an embodiment.

Detailed Description

Hereinafter, several embodiments of the present invention will be explained. The embodiments described below are embodiments for explaining examples of the present invention. The present invention is not limited to the following embodiments, and various modifications may be made without departing from the scope of the present invention. It is to be noted that not all of the structures described below are necessarily essential to the present invention.

1. Bonding material

The bonding material according to the present embodiment is integrated with a plant-derived thermoplastic resin and natural fibers. The binder can be suitably used in a method for producing a fiber formed product and an apparatus for producing a fiber formed product, which will be described later.

1.1. Thermoplastic resin derived from plant

The thermoplastic resin derived from a plant has thermoplastic properties. In addition, the raw material of the plant-derived thermoplastic resin is not derived from petroleum, but derived from plants, bacteria, algae, and the like.

The thermoplastic property is a property of being softened by heating, and for example, deformation or flow can be observed when the thermal properties are observed. The plant-derived thermoplastic resin may be amorphous or crystalline.

Examples of the plant-derived thermoplastic resin include polylactic acid, biological polyamide, polyhydroxyalkanoate, and isosorbide-containing resin. These substances are resins mainly composed of lactic acid, amino acid, hydroxy acid and isosorbide. The plant-derived thermoplastic resin may be derived from the plant as a whole, or 60.0% or more, preferably 80.0% or more, more preferably 90% or more, and even more preferably 95.0% or more of the plant-derived thermoplastic resin may be derived from the plant.

As a result of the fact that the bonding material of the present embodiment contains a plant-derived thermoplastic resin, the amount of petroleum-derived material used in a fiber molded product using a thermoplastic resin can be reduced, thereby reducing the environmental load. Further, since the plant-derived thermoplastic resin has thermoplastic properties, the fiber-molded product is further defibrated and used as a raw material, thereby facilitating recycling.

The plant-derived thermoplastic resin can be confirmed by examining, for example, the resin component is a biosynthesized resin. That is, the determination can be made by utilizing the fact that the optical anisotropy of the monomer unit is largely different between the chemical synthesis and the biosynthesis. For example, in the case of polylactic acid, when chemically synthesized lactic acid is used as a raw material, the raw material is a racemic body, whereas when plant-derived lactic acid is used as a raw material, the ratio of L-form or D-form is high. Therefore, by analyzing the monomer unit of polylactic acid by an analysis method having optical sensitivity, it is possible to determine whether the raw material of polylactic acid is chemically synthesized or derived from a plant.

The plant-derived thermoplastic resin is preferably polylactic acid, biological polyamide, polyhydroxyalkanoate, and isosorbide-containing resin, and particularly preferably polylactic acid, polyhydroxyalkanoate, and isosorbide-containing resin, from the viewpoint of good affinity with the first fiber described later, good adhesiveness, and the like. Various thermoplastic resins derived from plants can also be used.

The content of the plant-derived thermoplastic resin with respect to the entire binder is not particularly limited, but is, for example, 40% by mass or more and 98% by mass or less, preferably 50% by mass or more and 95% by mass or less, and more preferably 70% by mass or more and 90% by mass or less.

Although neither the glass transition temperature (Tg) nor the melting point (Tm) of the plant-derived thermoplastic resin is particularly limited, it is preferably in a rubbery state or a fluid state at a temperature such that the fibers described later are not damaged, and this temperature is, for example, 25 ℃ or higher and 150 ℃ or lower, preferably 30 ℃ or higher and 120 ℃ or lower, and more preferably 40 ℃ or higher and 100 ℃ or lower. The Tg and Tm of the plant-derived thermoplastic resin can be measured by, for example, Differential Scanning Calorimetry (DSC).

1.2. Natural fiber

The bonding material of this embodiment comprises natural fibers. The natural fiber is not particularly limited as long as it is derived from nature, and examples thereof include fibers made of cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, abaca, sisal, conifer, and broadleaf tree, and these fibers may be used alone, may be used by appropriately mixing them, and may be used as a regenerated fiber subjected to refining treatment or the like. When the fibrous formed product is a sheet such as paper, the natural fibers are more preferably cellulose fibers.

Examples of the raw material of the natural fiber include waste paper, waste cloth, and the like, but at least one of these fibers may be included. In addition, various surface treatments may also be performed. The material of the fiber may be pure, or may be a material containing a plurality of components such as impurities, additives, and other components.

When the natural fiber is an independent single fiber, the average diameter (the maximum length in the direction perpendicular to the longitudinal direction when the cross section is not a circle, or the diameter of a circle (equivalent circle diameter) when a circle having an area equal to the cross-sectional area is assumed) is 1 μm or more and 1000 μm or less, preferably 2 μm or more and 500 μm or less, and more preferably 3 μm or more and 200 μm or less, on average.

The average fiber length of the natural fiber is not particularly limited, but the length of one independent fiber along the longitudinal direction of the fiber is 1 μm or more and 5mm or less, preferably 2 μm or more and 3mm or less, and more preferably 3 μm or more and 2mm or less. When the binder is used as a raw material of a fiber molded product described later, the average fiber length of the natural fibers in the binder is preferably 0.5mm or more and 3.0mm or less, more preferably 0.8mm or more and 2.0mm or less, and further preferably 0.9mm or more and 1.8mm or less, from the viewpoint of improving the mechanical strength of the obtained fiber molded product.

1.3. Properties, structures and compositions of the bonding materials

The binder of the present embodiment can be in the form of powder. In the case of a powder, the particle diameter (volume-based average particle diameter) of the particles of the binder is, for example, 10.0mm or less, preferably 5.0mm or less, and more preferably 1.0mm or less. When the binder is used as a raw material of a fibrous molded article to be described later, the particle diameter (volume-based average particle diameter) of the binder particles is preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, and particularly preferably 20 μm or less. In this case, when the average particle diameter is small, the gravity acting on the binder becomes small when a fiber formed product described later is formed, and therefore, the separation from the first fibers due to its own weight can be suppressed. Further, if the binder is within the above particle diameter range, it is difficult to sufficiently detach from the first fibers, and the first fibers can be bonded to the first fibers.

The outer shape of the particles of the binder is preferably approximately spherical, but is not particularly limited, and may be disk-shaped, spindle-shaped, amorphous, or the like. Although the volume average particle diameter of the entire particles as the binder is appropriately set, the volume average particle diameter, the particle diameter distribution, and the like of the particles of the binder can be adjusted by a classification operation or the like.

The volume average particle diameter of the particles of the binding material can be directly observed with a digital micro-meter (VHK-7000, Keyence), and the particle diameter can be directly measured and calculated by image processing.

The bonding material of the present embodiment is integrated with the plant-derived thermoplastic resin and the natural fiber. Here, the state in which the plant-derived thermoplastic resin and the natural fiber are integrally formed means a state in which the plant-derived thermoplastic resin or the natural fiber is hardly separated from the particles of the binding material. That is, the state in which the plant-derived thermoplastic resin and the natural fiber are integrally formed in the particles of the binding material means a state in which the natural fibers are bonded to each other by the plant-derived thermoplastic resin, a state in which the natural fibers are structurally (mechanically) fixed to the plant-derived thermoplastic resin, a state in which the plant-derived thermoplastic resin and the natural fibers are aggregated by electrostatic force, van der waals force, or the like, and a state in which the plant-derived thermoplastic resin and the natural fibers are chemically bound.

In addition, the state in which the plant-derived thermoplastic resin and the natural fiber are integrally formed in the particles of the binding material may be a state in which the natural fiber is wrapped in the plant-derived thermoplastic resin, a state in which the natural fiber is attached to the plant-derived thermoplastic resin, or a state in which both states coexist.

The mass ratio of the plant-derived thermoplastic resin to the natural fiber in the binder (plant-derived thermoplastic resin/natural fiber) is 1/5 or more and 10/1 or less, preferably 1/4 or more and 6/1 or less, and more preferably 1/3 or more and 4/1 or less. When the mass ratio is in the above range, the function of bonding the first fibers described later can be further improved, and the function of maintaining and improving the mechanical strength and paper force of the fiber molded product such as stretching and tearing can be further improved.

1.4. Other ingredients

The binder may contain other components as long as the effects of the thermoplastic resin derived from a plant and the natural fibers are not impaired. Examples of such components include synthetic resins, colorants, coagulation inhibitors, ultraviolet absorbers, flame retardants, antistatic agents, static control agents, organic solvents, surfactants, antibacterial agents, preservatives, antioxidants, and oxygen absorbers. These components may be blended as one component of the binder, or may be blended separately from the particles of the binder.

Examples of the synthetic resin include polyethylene, polypropylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyethylene succinate, polybutylene succinate, polyhydroxybutyrate, polylactic acid, polyphenylene sulfide, polyether ether ketone, polyvinyl chloride, polystyrene, polymethyl (meth) acrylate, acrylonitrile-butadiene-styrene resin, polycarbonate, modified polyphenylene ether, polyether sulfone, polyether imide, and polyamide imide. Further, the synthetic resin may be copolymerized or modified, or a styrene-based resin, an acrylic resin, a styrene-acrylic copolymer resin, an olefin-based resin, a vinyl chloride-based resin, a polyester-based resin, a polyamide-based resin, a polyurethane-based resin, a polyvinyl alcohol-based resin, a vinyl ether-based resin, an N-vinyl-based resin, a styrene-butadiene-based resin, or the like, which is converted to amorphous by copolymerization or modification, may be used.

The binder has a function of binding first fibers described later when used as a raw material of a fiber molded product. In addition, the binder has a function of maintaining and improving mechanical strength and paper force of the fiber formed product such as stretching and tearing when used as a raw material of the fiber formed product. Whether or not such a binder is contained in the fiber-formed product can be confirmed by, for example, IR (infrared spectroscopy), NMR (nuclear magnetic resonance), MS (mass spectrometry), various chromatographies, and the like.

1.5. Action and Effect, etc

When the binder of the present embodiment is applied to a fiber formed product, the mechanical strength and paper strength of the fiber formed product such as stretching and tearing can be sufficiently obtained.

Further, since the conventional petroleum-derived resins have the same monomer structure, secondary crystallization may progress with the passage of time to embrittle the resin itself. However, since the thermoplastic resin derived from a plant has a certain degree of variation in the monomer structure, the thermoplastic resin is less likely to undergo secondary crystallization and is less likely to become brittle, and, for example, when a fiber molded product is applied, the thermoplastic resin can maintain quality such as mechanical strength for a long period of time.

2. Method for producing bonding material

The method for producing the bonding material of the present embodiment includes kneading the plant-derived thermoplastic resin and the natural fiber to integrate the plant-derived thermoplastic resin and the natural fiber.

The method for producing the bonding material of the present embodiment includes, for example: a kneading step of melt kneading a plant-derived thermoplastic resin and a natural fiber to form a binder; a granulating step of granulating the binder; and a pulverization step of pulverizing the granulated binder.

In the kneading step, a thermoplastic resin derived from a plant and a natural fiber are melt-kneaded. The plant-derived thermoplastic resin and the natural fiber can be prepared in any form. In the kneading step, the content of the plant-derived thermoplastic resin and the natural fiber relative to the total amount of the binder can be adjusted.

When a plant-derived thermoplastic resin and a natural fiber are melt-kneaded, a bonding material in which both are integrated can be obtained. The temperature for melt-kneading can be appropriately set by adjusting the melting temperature of the plant-derived thermoplastic resin or the like, the conditions of the apparatus for melt-kneading, and the like. The binder formed by melt-kneading may be directly pulverized into a powdery binder, or may be granulated into a granular binder through a granulation step after extrusion molding. When the binder is formed by melt kneading, the binder can be obtained by granulating, pulverizing, or a combination thereof, and the like, and has a predetermined volume average particle diameter.

The melt mixing and kneading can be carried out using, for example, a kneader, a banbury mixer, a single-screw extruder, a multi-screw extruder, a twin-roll, a three-roll, a continuous kneader, a continuous twin-roll, or the like. The pulverization can be carried out by a pulverizer such as a hammer mill, a pin mill, a cutter, a pulper, a turbo mill, a disc mill, a screen mill, or a jet mill. By appropriately combining them, particles or powder of the binder can be obtained.

The step of pulverizing may be performed in stages such as a coarse pulverizing step so that the particle diameter is approximately 1mm, and a fine pulverizing step so that the particle diameter is the target particle diameter. Even in such a case, the devices shown in the examples can be used in each stage. In order to further improve the efficiency of grinding the binder, a freeze grinding method may be used. The powder of the bonding material obtained in this way may be used as the bonding material, and may contain powders having various particle diameters. Therefore, classification may be performed using a known classification device as needed.

3. Method for producing fiber formed article

The method for producing a fiber molded product according to the present embodiment is a method for producing a fiber molded product in which a plurality of first fibers are bonded by a bonding material by heating the first fibers subjected to defibration and the bonding material in which the plant-derived thermoplastic resin and the natural fibers are integrated in a mixed state.

The fiber formed product of the present embodiment includes the above-described binder and the plurality of first fibers, and is a substance in which the plurality of first fibers are bonded by the binder. The fiber molding is mainly formed into a sheet. However, the sheet-like shape is not limited to the sheet-like shape, and may be a plate-like shape, a sheet-like shape, or a shape having concavities and convexities. Typical examples of the fiber formed product in the present specification include paper and nonwoven fabric. The paper includes, for example, a form in which pulp and waste paper are used as raw materials and formed into a sheet, and includes recording paper, wallpaper, wrapping paper, colored paper, drawing paper, kenter paper, and the like for writing or printing. The nonwoven fabric is thick or low in strength compared with paper, and includes general nonwoven fabrics, fiberboards, toilet paper, kitchen paper, cleaning materials, filter papers, liquid absorbing materials, sound absorbers, cushioning materials, mats, and the like.

The first fibers contained in the fiber formed product of the present embodiment are not particularly limited, and a wide range of fiber materials can be used. Examples of the fibers include natural fibers (animal fibers and plant fibers), chemical fibers (organic fibers, inorganic fibers, and organic-inorganic composite fibers), and more specifically, fibers made of cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, abaca, sisal, coniferous tree, and broadleaf tree, and the like, and these fibers may be used alone, or they may be used by appropriately mixing them, or they may be used as regenerated fibers subjected to refining treatment or the like.

As the raw material of the first fibers, for example, waste paper, waste cloth, and the like are cited, but at least one of fibers obtained from them may be included. In addition, various surface treatments may also be performed. The material of the first fibers may be pure, or may be a material containing a plurality of components such as impurities, additives, and other components.

When the first fibers are independent fibers, the average diameter (the maximum length in the direction perpendicular to the longitudinal direction when the cross section is not a circle, or the diameter (equivalent circle diameter) of a circle when a circle having an area equal to the area of the cross section is assumed) is 1 μm or more and 1000 μm or less, preferably 2 μm or more and 500 μm or less, and more preferably 3 μm or more and 200 μm or less.

Although the length of the first fiber is not particularly limited, the length of one individual fiber in the longitudinal direction of the fiber is 1 μm or more and 5mm or less, preferably 2 μm or more and 3mm or less, and more preferably 3 μm or more and 2mm or less.

The method of producing a fiber molded product according to the present embodiment includes a mixing step of mixing the above-described binder and the first fibers, a stacking step of stacking the mixed first fibers and the binder, and a bonding step of bonding the fibers of the stacked product and the binder.

The mixing process can be performed, for example, by mixing the first fibers with the binder in air. The deposition step can be performed by depositing the mixture mixed in the mixing step on a net or the like while dropping the mixture in the air. The adhesion step can be performed by heating the deposit obtained in the deposition step with a hot press, a hot roll, or the like to melt the bonding material.

The method for producing a fiber formed product according to the present embodiment may include, as necessary, at least one step selected from the group consisting of: cutting pulp sheets, waste paper and the like as raw materials in the air; a defibering step of defibering the raw material in air into a fibrous form; a classification step of classifying the foreign matter or the fiber shortened by the defibering in the air from the defibered material; a screening step of screening long fibers (long fibers) or an undeveloped sheet that has not been sufficiently defibered from the defibered product in air; a pressing step of pressing at least one of the deposit and the fiber-formed product; a cutting step of cutting the fiber molded product; and a packaging step for packaging the fiber molded product.

In the fiber formed product, the mixing ratio of the first fibers and the binder can be appropriately adjusted according to the strength, the application, and the like of the fiber formed product to be manufactured. If the fiber molded article is office paper such as copy paper, the ratio of the binder to the fibers is, for example, 5% by mass or more and 70% by mass or less.

According to the method for producing a fiber formed product of the present embodiment, since the above-described binder is used, even if the amount of the petroleum-derived material used is reduced, a fiber formed product having sufficient mechanical strength such as tensile strength and tear strength and sufficient paper strength can be produced. Further, the obtained fiber-formed product is also easily recycled.

4. Apparatus for producing fiber formed article

The apparatus for producing a fiber molded product according to the present embodiment includes at least a heating section that heats the first fibers that have been defibrated and the bonding material that is a combination of the plant-derived thermoplastic resin and the natural fibers, and bonds the plurality of first fibers together with the bonding material.

An example of a fiber formed product manufacturing apparatus according to the present embodiment will be described with reference to the drawings. Fig. 1 is a schematic view of a fiber-formed product manufacturing apparatus 100 according to the present embodiment. In the fiber molded product manufacturing apparatus 100, the first fibers that have been defibrated and the bonding material that integrates the plant-derived thermoplastic resin and the natural fibers are heated to produce the sheet S as the fiber molded product, and the plurality of first fibers are bonded to each other by the bonding material.

As shown in fig. 1, the fiber formed product manufacturing apparatus 100 includes, for example, a supply section 10, a rough crushing section 12, a defibration section 20, a screening section 40, a first web forming section 45, a rotating body 49, a mixing section 50, a stacking section 60, a second web forming section 70, a sheet forming section 80, and a cutting section 90.

The supply unit 10 supplies the raw material to the coarse crushing unit 12. The supply unit 10 is, for example, an automatic charging unit for continuously charging the raw material into the coarse crushing unit 12. The raw material supplied through the supply portion 10 includes, for example, the above-described first fibers such as waste paper or pulp sheets.

The rough crushing section 12 cuts the raw material supplied through the supply section 10 in an atmosphere or the like to form chips. The shape and size of the chips are, for example, chips in a few cm square. In the illustrated example, the rough crush portion 12 has a rough crush blade 14, and can cut the charged raw material by the rough crush blade 14. As the rough crush portion 12, a shredder is used, for example. The raw material cut by the rough crushing section 12 is received by the hopper 1 and then transferred to the defibration section 20 through the pipe 2.

The defibering unit 20 performs defibering of the raw material cut by the rough crushing unit 12. Here, "defibering" means that a raw material obtained by bonding a plurality of fibers is separated into fibers one by one. The defibration section 20 also has a function of separating substances such as resin particles, ink, toner, and a bleeding inhibitor, which are attached to the raw material, from the fibers.

The substance passing through the defibration section 20 is referred to as "defiberized substance". The "defibrinated product" may include, in addition to the defibrinated product fiber, resin particles separated from the fiber during defibrination, coloring materials such as ink and toner, a barrier material, and additives such as a paper strength enhancer. The shape of the defibrinated object after being disassembled is rope-shaped. The defibered product may be present in a state of not being entangled with other defibered fibers, that is, in a state of being independent of each other, or may be present in a state of being entangled with other defibered products in a lump, that is, in a state of being formed into a lump.

The defibration unit 20 performs defibration in a dry manner. Here, a method of performing a treatment such as defibration in a gas such as air, not in a liquid, is referred to as a dry method. As the defibration section 20, for example, an impeller mill is used. The defibration section 20 has a function of generating a gas flow such that the raw material is sucked and the defibrated material is discharged. In this way, the defibration section 20 sucks the raw material from the inlet 22 together with the air flow by the air flow generated by itself to perform the defibration process, and conveys the defibrated material to the outlet 24. The defibered product having passed through the defibering unit 20 is transferred to the screen unit 40 through the pipe 3. The air flow for conveying the defibered material from the defibering unit 20 to the screening unit 40 may be the air flow generated by the defibering unit 20, or may be an air flow generating device such as a blower, and the air flow may be used.

The screening section 40 introduces the defibered material, which has been defibered by the defibering section 20, from the introduction port 42, and screens the defibered material according to the length of the fiber. The screening portion 40 includes a drum portion 41 and a housing portion 43 that houses the drum portion 41. As the drum part 41, for example, a sieve is used. The drum portion 41 has a net, and can distinguish a first sorted material in which fibers or particles smaller than the mesh size of the net, that is, a material passing through the net, from a second sorted material in which fibers, undeveloped pieces, or clumps larger than the mesh size of the net, that is, a material not passing through the net. For example, the first sorted material is transferred to the stacking unit 60 through the pipe 7. The second screened material is returned from the discharge port 44 to the defibration section 20 via the tube 8. Specifically, the drum portion 41 is a cylindrical screen that is rotationally driven by a motor. As the net of the drum portion 41, for example, a wire mesh, a porous metal net obtained by drawing a metal plate provided with a slit, and a punched metal plate obtained by forming a hole in a metal plate by a press or the like are used.

The first web forming section 45 conveys the first screen passed through the screen section 40 to the tube 7. The first web forming section 45 includes a mesh belt 46, a tension roller 47, and a suction mechanism 48.

The suction mechanism 48 is capable of sucking the first screen dispersed in the air through the opening of the screen section 40 onto the mesh belt 46. The first screen is stacked on the moving mesh belt 46 and forms the web V. The basic structures of the mesh belt 46, the tension roller 47, and the suction mechanism 48 are the same as those of the mesh belt 72, the tension roller 74, and the suction mechanism 76 of the second web forming portion 70 described below.

The web V passes through the screen 40 and the first web forming section 45, and is formed into a state of being rich in air and being soft and fluffy. The web V stacked on the mesh belt 46 is thrown into the tube 7 and conveyed to the stacking portion 60.

The rotating body 49 can cut the web V. In the illustrated example, the rotating body 49 has a base portion 49a and a protrusion portion 49b protruding from the base portion 49 a. The projection 49b has a plate-like shape, for example. In the illustrated example, four protrusions 49b are provided, and four protrusions 49b are provided at equal intervals. The base portion 49a is rotated in the direction R, so that the projection portion 49b can be rotated about the base portion 49 a. By cutting the web V with the rotating body 49, for example, the variation in the amount of the defibrated material per unit time supplied to the accumulating portion 60 can be reduced.

The rotator 49 is provided in the vicinity of the first web forming portion 45. In the illustrated example, the rotating body 49 is provided in the vicinity of the tension roller 47a located on the downstream side in the path of the web V. The rotating body 49 is provided at a position where the protrusions 49b can contact the web V and are not in contact with the web 46 on which the web V is stacked. This can suppress the wear of the mesh belt 46 due to the projection 49 b. The shortest distance between the projection 49b and the mesh belt 46 is, for example, 0.05mm or more and 0.5mm or less. This is the distance that the web sheet V can be cut by the web tape 46 without being damaged.

The mixing part 50 mixes the first screen passing through the screen part 40 with the additive including the binding material. The mixing section 50 includes an additive supply section 52 for supplying an additive, a pipe 54 for transporting the first sorted material and the additive, and a blower 56. In the illustrated example, the additive is supplied from the additive supply portion 52 to the pipe 54 via the hopper 9. The tube 54 is continuous with the tube 7.

In the mixing section 50, an air flow is generated by the blower 56, and the first screen material and the additive can be mixed and conveyed in the pipe 54. The mechanism for mixing the first screen material and the additive is not particularly limited, and may be a device that performs stirring by a blade rotating at a high speed, or a device that uses rotation of a container such as a V-shaped stirrer.

As the additive supply unit 52, a screw feeder as shown in fig. 1, a disk feeder not shown, or the like is used. The additive supplied from the additive supply part 52 includes a binder. At the point in time when the bonding material is supplied, the plurality of first fibers are not bonded together. The bonding material melts as it passes through the sheet forming portion 80, thereby bonding the plurality of fibers together.

The additive supplied from the additive supply portion 52 may contain, in addition to the binder, a colorant for coloring the first fibers, a coagulation inhibitor for inhibiting coagulation of the first fibers or coagulation of the binder, and a flame retardant for making the fibers or the like difficult to burn, depending on the type of the sheet to be manufactured. The mixture having passed through the mixing section 50 is transferred to the stacking section 60 via the pipe 54.

The stacking section 60 introduces the mixture passing through the mixing section 50 from the inlet 62, unwinds the entangled object, and drops the object while dispersing the object in the air. This enables the accumulation section 60 to accumulate the mixture on the second web forming section 70 with good uniformity.

The stacking portion 60 includes a roller portion 61 and a housing portion 63 for housing the roller portion 61. A rotating cylindrical screen is used as the drum portion 61. The drum portion 61 has a net, and drops fibers or particles contained in the mixture passing through the mixing portion 50 and smaller than the mesh size of the net. The structure of the drum portion 61 is, for example, the same as that of the drum portion 41.

The "screen" of the drum portion 61 may not have a function of screening a specific object. That is, the "sieve" used as the drum part 61 means a member having a net, and the drum part 61 may drop all the mixture introduced into the drum part 61.

The second web forming portion 70 stacks the passage passed through the stacking portion 60, thereby forming the web W. The second web forming section 70 has, for example, a mesh belt 72, a tension roller 74, a suction mechanism 76.

The mesh belt 72 moves while accumulating the passing objects passing through the opening of the accumulation section 60. The mesh belt 72 is stretched by the stretching roller 74, and air passes through the mesh belt with difficulty. The mesh belt 72 is rotated and moved by the tension roller 74. The web W is formed on the mesh belt 72 by continuously accumulating the passes passing through the accumulation section 60 while the mesh belt 72 is continuously moving.

The suction mechanism 76 is disposed below the mesh belt 72. The suction mechanism 76 is capable of generating a downward-directed airflow. The mixture dispersed in the air by the accumulation section 60 is sucked onto the mesh belt 72 by the suction mechanism 76. This can increase the discharge speed of the discharge from the stacking unit 60. Further, by the suction mechanism 76, a down-flow can be formed on the falling path of the mixture, and the fluff or the additive can be prevented from being entangled during the falling.

As described above, the web W in a soft and fluffy state rich in air is formed by passing through the stacking portion 60 and the second web forming portion 70. The web W stacked on the mesh belt 72 is conveyed toward the sheet forming portion 80.

In the illustrated example, a humidity control unit 78 for performing humidity control of the web W is provided. The humidifying section 78 can adjust the amount ratio of the web W to water by adding water or water vapor to the web W.

The sheet forming section 80 applies pressure and heat to the web W stacked on the mesh belt 72, thereby forming the sheet S. In the sheet forming section 80, the plurality of fibers in the mixture can be bonded to each other via the additive by applying heat to the mixture of the defibrinated material and the additive mixed together in the web W.

The sheet forming section 80 includes a pressing section 82 that presses the web W, and a heating section 84 that heats the web W pressed by the pressing section 82. The pressing portion 82 is constituted by a pair of reduction rollers 85, and applies pressure to the web W. The web W is made smaller in thickness by being pressed, and the bulk density of the web W is increased. As the heating section 84, for example, a heating roller, a hot press molding machine, a hot plate, a warm air blower, an infrared heater, and a flash fixing device are used. In the illustrated example, the heating unit 84 includes a pair of heating rollers 86. By using the heating section 84 as the heating roller 86, the sheet S can be formed while continuously conveying the web W, as compared with the case where the heating section 84 is configured as a plate-like pressing device. The reduction roll 85 and the heating roll 86 are disposed such that their rotation axes are parallel to each other, for example. Here, the calender rolls 85 can apply a higher pressure to the web W than the pressure applied to the web W by the heating roll 86. The number of the reduction rolls 85 and the heating rolls 86 is not particularly limited.

The cutting section 90 cuts the sheet S formed by the sheet forming section 80. In the illustrated example, the cutting section 90 has a first cutting section 92 that cuts the sheet S in a direction intersecting the conveying direction of the sheet S, and a second cutting section 94 that cuts the sheet S in a direction parallel to the conveying direction. The second cutting portion 94 cuts the sheet S passing through the first cutting portion 92, for example.

In this manner, a single sheet S of a predetermined size is formed. The cut sheet S is discharged to the discharge section 96.

According to the apparatus for producing a fiber formed product of the present embodiment, since the above-described binder is used, the amount of the petroleum-derived material used can be reduced, and the mechanical strength such as tensile strength and tear strength and paper strength of the obtained fiber formed product can be sufficiently obtained. The fiber formed product obtained is also easily reused.

5. Examples and comparative examples

Although the present invention will be further described below by way of examples and comparative examples, the present invention is not limited to the following examples.

5.1. Manufacture of bonding materials

Production examples 1 to 12

A heating stirrer (upper blade: kneading type, lower blade: high-cycle/high-load type, heater and thermometer attached, capacity 20L, product name Henschel stirrer FM20C/I, manufactured by Mitsui mine Co., Ltd.) was heated to 140 ℃ to charge cellulose flakes (obtained by cutting a pulp NDP-T manufactured by Nippon paper-making Co., Ltd., an average fiber diameter of 25 μm, an average fiber length of 1.8mm, a flake having a width of 60cm, a length of 80cm and a thickness of 1.1mm and composed of 90% of an alpha-cellulose content into flakes having a width of 20cm and a length of 80 cm), and kneading was performed at an average circumferential velocity of 50 m/sec. At the point of about 2 minutes, the cellulose fiber product changed to a flocculent form (fiber powder 1). The fiber lengths of the cellulose raw materials and the kneading time were changed by adjusting the fiber powders 3 to 5 as follows.

Then, after the resins 1 to 4 were charged into the heating stirrer (see below), kneading was continued at an average peripheral speed of 50 m/sec. The power of the motor at this time was 2.5 kW. When the temperature of the stirrer reached 120 ℃, MPP (maleic acid-modified polypropylene: MG-670P, manufactured by Rakikai vitamin Co., Ltd.) was charged and kneading was continued.

At the point in time when about 10 minutes has elapsed, the power begins to rise. After another 1 minute, the peripheral speed dropped to a low speed of 25m/sec, since the power rose to 4 kW. Then, the power starts to rise again by continuing the low-speed kneading. After starting the low speed rotation for 1 minute and 30 seconds, the discharge port of the agitator was opened and discharged to the connected cooling agitator since the power reached 5 kW.

The cooling mixer (rotating blade: standard cooling blade, water cooling unit (20 ℃ C.) and thermometer, capacity 45L, product name cooling mixer FD20℃/K, manufactured by Mitsui mine Co., Ltd.) started kneading at an average circumferential speed of 10m/sec, and ended kneading at a point when the temperature in the mixer reached 80 ℃. The mixture of cellulose fibers and resin is cured to obtain various pellets having a diameter of about several millimeters to 2 cm.

Resin 1: "TERRAMAC TE-2000" manufactured by Unitika corporation, polylactic acid

Resin 2: "Zytel HTN510EFT NC 010" manufactured by Dupont, Inc., Bio-Polyamide

Resin 3: PHBH, a polyhydroxyalkanoate, manufactured by Bell chemical Co., Ltd

Resin 4: "PLANEXT H-5000" manufactured by DIREN corporation, containing isosorbide resin

Fiber powder 1: the length of the fiber is 1.5mm

Fiber powder 2: fiber length 3.0mm (used without kneading treatment of linter pulp.)

Fiber powder 3: the fiber length was 0.5mm (the kneading time was changed to 20 minutes, and the production was carried out in the same manner as in the production example.)

Fiber powder 4: the fiber length was 0.8mm (the kneading time was changed to 10 minutes, and the production was carried out in the same manner as in the production example.)

Fiber powder 5: the fiber length was 2.0mm (the kneading time was changed to 20 minutes for cellulose fibers changed to linter pulp), and the fibers were produced in the same manner as in production example.)

Fiber powder 6: fiber length 1.7mm (Kevlar, Dupont)

Comparative production example 1

The cellulose sheet of production example 1 was replaced with Kevlar (petroleum aramid fiber, fiber length 1.7 mm: non-natural fiber: fiber powder 6) manufactured by Toray corporation, and the same production was carried out as follows.

Comparative production example 2

The cellulose sheet of production example 1 was not loaded, and the production was carried out in the same manner.

Comparative production example 3

The resin of production example 1 was replaced with polyethylene terephthalate (made by Tekken Co., Ltd., titanium-based catalyst grade) (resin 5: a petroleum-derived thermoplastic resin), and the production was carried out in the same manner as described below.

Comparative production example 4

The resin of production example 1 was replaced with an alphatized cationized starch (M-350B, Trillia corporation) (resin 6: a plant-derived thermosetting resin), and the production was carried out in the same manner as described below.

Comparative production example 5

The resin of production example 1 was replaced with a rosin ester (AA-V, manufactured by Mitsukawa chemical industries, Ltd.) (resin 7: a plant-derived thermosetting resin), and the production was carried out in the same manner as described below.

TABLE 1

5.2. Production of fiber-formed article

The particles of the binder obtained in each example were pulverized to prepare a binder powder having a volume average particle size of 20 μm. 22.5g of 2 softwood bleached kraft pulp and 7.5g of the binder material of each example were weighed out, and put into a clean wide-mouthed paste bottle (capacity 1000ml) made of polyethylene in this order, and the lid was closed. When the bottle was mounted on the ball mill rotation mount, the rotational speed was adjusted so that the peripheral speed of the bottle became 15m/min, and each example was rotated for 8 minutes. The obtained mixtures of the respective examples were taken out so as to be free from vibration and air flow as much as possible, and hot-pressed at a temperature of 150 ℃ and a pressure of 15MPa for 30 seconds to melt and cool the resins, thereby obtaining fiber molded articles of the respective examples and comparative examples shown in table 2.

5.3. Evaluation of paper force (immediately after production)

The fiber formed article of each example was cut into 60mm × 100mm, arranged so that the length of the cut fiber formed article in the vertical direction became 60mm by a universal testing machine (AGS-10N manufactured by shimadzu corporation), and stretched in the vertical direction by fixing the upper and lower sides of the fiber formed article with a jig, thereby measuring the specific tensile strength. The evaluation was performed according to the following criteria, and the results are shown in table 2.

A: 30Nm/s or more

B: 27Nm/s or more and less than 30Nm/s

C: 23Nm/s or more and less than 27Nm/s

D: 20Nm/s or more and less than 23Nm/s

E: less than 20Nm/s

5.4. Evaluation of paper Strength (after Heat resistance test)

The fiber formed article of each example was stored at 90 ℃ for 30 days, and then the paper strength was evaluated in the same manner as described above. The evaluation was performed according to the following criteria, and the results are shown in table 2.

A: the specific tensile strength is maintained at 99% or more as compared with the initial stage

B: the specific tensile strength is maintained at 97% or more and less than 99% compared with the initial stage

C: the specific tensile strength is maintained at 95% or more and less than 97% compared with the initial stage

D: the specific tensile strength is maintained at 90% or more and less than 95% compared with the initial stage

E: the specific tensile strength is maintained at less than 90% compared to the initial stage

5.5. Evaluation of repeated regeneration

The fiber formed product obtained in each example was subjected to dry defibration as a raw material, and the fiber formed product was regenerated without adding another raw material. This operation was carried out three times for each example, thereby obtaining each example regenerated fiber formed article. After that, the paper strength was evaluated in the same manner as described above. The evaluation was performed according to the following criteria, and the results are shown in table 2.

A: the specific tensile strength is maintained at 90% or more compared with the initial stage

B: the specific tensile strength is maintained at 80% or more and less than 90% compared with the initial stage

C: the specific tensile strength is maintained at 70% or more and less than 80% compared with the initial stage

D: the specific tensile strength is maintained at 60% or more and less than 50% compared with the initial stage

E: the specific tensile strength is maintained at less than 50% compared to the initial stage

5.6. Evaluation of fiber stain

The presence of black spots on the surface of the fiber-molded product was visually observed and evaluated, and the total absence of black spots was evaluated as a, the marginal observation was evaluated as B, and the clear observation was evaluated as C.

TABLE 2

5.7. Evaluation of JI fruit

As is clear from table 2, the first fibers obtained by defibration and the binder in which the plant-derived thermoplastic resin and the natural fibers are integrated are heated in a mixed state, and the plurality of first fibers are bonded by the binder, whereby the fiber molded products of the respective examples have excellent paper strength and recyclability.

The present invention is not limited to the above-described embodiments, and various modifications can be further implemented. For example, the present invention includes substantially the same structures (structures having the same functions, methods, and results, or structures having the same objects and effects) as those described in the embodiments. The present invention includes a structure in which the nonessential portions of the structures described in the embodiments are replaced. The present invention includes a structure that achieves the same operational effects or the same objects as the structures described in the embodiments. The present invention includes a configuration in which a known technique is added to the configurations described in the embodiments.

Description of the symbols

1 … hopper; 2. 3, 7, 8 … tubes; 9 … hopper; 10 … supply part; 12 … coarse crushing part; 14 … coarse crushing blade; 20 … defibering part; 22 … introduction port; 24 … discharge ports; 40 … screening part; 41 … a roller portion; 42 … introduction port; 43 … housing portion; 44 … discharge port; 45 … a first web forming portion; 46 … mesh belt; 47. 47a … tension roller; 48 … suction mechanism; 49 … a rotating body; 49a … base; 49b … projection; a 50 … mixing section; 52 … an additive supply part; 54 … tubes; a 56 … blower; 60 … stacking part; 61 … roller part; 62 … introduction port; 63 … housing portion; 70 … second web forming portion; 72 … mesh belt; 74 … tension roller; 76 … suction mechanism; 78 … humidity conditioning section; 80 … sheet forming part; 82 … pressure part; 84 … heating section; 85 … calender rolls; 86 … heated roller; a 90 … cut-off portion; 92 … a first cut-out; 94 … second cut-out; 96 … discharge; 100 … fiber forming object manufacturing device.

Claims

1. A method for producing a fiber-formed product, wherein,

the method for manufacturing the composite fiber comprises the steps of heating a first fiber subjected to defibration and a bonding material in which a plant-derived thermoplastic resin and a natural fiber are integrated in a mixed state, and bonding a plurality of the first fibers with the bonding material.

2. The method for producing a fiber formed article according to claim 1,

the natural fibers are cellulose fibers.

3. The method of producing a fiber formed article according to claim 1 or 2,

the plant-derived thermoplastic resin is selected from at least one of polylactic acid, biological polyamide, polyhydroxyalkanoate and isosorbide-containing resin.

4. The method for producing a fiber formed article according to claim 1,

the mass ratio of the plant-derived thermoplastic resin to the natural fiber in the binder, i.e., the plant-derived thermoplastic resin/natural fiber, is from 1/3 to 4/1.

5. The method for producing a fiber formed article according to claim 1,

the natural fibers in the binding material have an average fiber length of 0.8mm to 2.0 mm.

6. An apparatus for producing a fiber-formed product, wherein,

the fiber processing apparatus is provided with a heating section that heats a first fiber that has been defibrated and a bonding material in which a plant-derived thermoplastic resin and a natural fiber are integrated, thereby bonding a plurality of the first fibers together with the bonding material.

7. The apparatus for manufacturing a fiber formed article according to claim 6,

the fiber-separating device is provided with a fiber-separating unit that separates a raw material containing fibers to obtain the first fibers, and a mixing unit that mixes the first fibers with the binder.

8. The apparatus for manufacturing a fiber formed article according to claim 7,

the fiber bundle is provided with a stacking section for stacking the first fibers and the bonding material mixed in the mixing section.

9. The apparatus for producing a fiber formed article according to any one of claims 6 to 8,

10. The apparatus for producing a fiber formed product according to claim 6,

and a pressing section that presses the first fibers that have passed through the heating section and have been bonded by the bonding material.

11. The apparatus for manufacturing a fiber formed article according to claim 6,

12. The apparatus for manufacturing a fiber formed article according to claim 6,

13. A bonding material, wherein,

the thermoplastic resin derived from a plant is integrated with the natural fiber.

14. A method for producing a bonding material, wherein,

comprising kneading a plant-derived thermoplastic resin and a natural fiber to integrate the plant-derived thermoplastic resin and the natural fiber.