JP5648275B2 - Papermaking material for natural fiber molded article and method for producing the same - Google Patents

Description

  The present invention relates to a papermaking material for a natural fiber molded product and a method for producing the same, and more particularly, to a papermaking material for a molded product composed of natural fibers occupying a majority weight% content and a method for producing the same.

  Conventionally, fiber reinforced plastics or fiber reinforced plastics (FRP) in which a fiber material such as chemical fiber, glass fiber, metal fiber, carbon fiber or the like is contained in a base plastic as a reinforcing material are known. Such an FRP is obtained by kneading a fiber material having a relatively short fiber length (for example, 3 to 12 mm) in a thermoplastic plastic that has been made fluid by heating, and then forming the desired shape by a method such as injection molding or extrusion molding. Often finished into molded parts.

  For example, in Patent Document 1, a natural fiber is added to a thermoplastic resin as a reinforcing agent, and a compatibilizer is added to the thermoplastic resin, and then extruded, drawn, compressed, or the like to be molded into a predetermined shape and used for a vehicle body. Techniques for replacing wood have been proposed.

JP-A-10-235747

  However, in the technology disclosed in Patent Document 1, the composition ratio of the base material and the compatibilizers such as polypropylene and polyethylene and petroleum-derived resins is overwhelmingly larger than that of natural fibers that are reinforcing materials. In recent years when there is concern about soaring resources and depletion, it is not preferable in terms of cost and environment. In particular, when such a molded product becomes a waste, petroleum-derived resins are not biodegraded in nature, and thus there are significant environmental problems.

  In addition, it is necessary to use a natural fiber having a relatively short fiber length so as not to hinder the fluidity of the resin at the time of injection molding or extrusion molding. However, not only the natural fiber but also a relatively short fiber material is contained as a reinforcing material. In FRP, the orientation of the fiber material tends to be aligned with the flow direction of the resin during molding, and the mechanical strength of the molded product as the final product may vary depending on the direction.

  The object of the present invention is to provide a natural fiber material that is inexpensive and friendly to the natural environment due to its high content ratio of natural fiber materials, and that high mechanical strength can be obtained in any direction by binding natural fibers in an intertwined state. An object of the present invention is to provide a papermaking material for a fiber molded product and a method for producing the material.

The paper making material of the natural fiber molded product according to the present invention is a method for discharging the dispersion water in which a natural fiber having a binder resin powder attached around the fiber is dispersed into a paper making tank in which a paper making net is arranged, and discharging the water evenly. Temporarily stored on a net and drained from the lower part of the papermaking tank, the natural fibers are entangled with each other by the papermaking net, and then the papermaking taken on the net is dehydrated. And a papermaking material for a natural fiber molded product obtained by drying, wherein the natural fiber occupies a content exceeding 50% by weight in the molded product, and the binder resin powder is used for the heat compression molding in the subsequent step. entangled natural fibers are those which are coupled to each other at each junction point, wherein the natural fibers are relatively the first natural fibers long fibers occupying 70 to 80% by weight in the molded article, the remaining 10 Consists of a second natural fiber relatively short fibers account for 15 wt%, the second natural fiber is positioned so as to fill a gap between the first natural fiber entangled in the papermaking material, It functions effectively to keep the binder resin powder having a particle size of 1 to 100 μm in the papermaking product without flowing out during the drainage.

  In the papermaking material of the natural fiber molded product according to the present invention, the content of the natural fiber in the molded product is 70 wt% or more and less than 100 wt%, and the content of the binder resin powder in the molded product is 30 wt%. % Or less and preferably more than 0% by weight.

  Moreover, in the papermaking material of the natural fiber molded product according to the present invention, the content of the natural fiber in the molded product is 80 wt% or more and 95 wt% or less, and the content of the binder resin powder in the molded product is More preferably, it is 20% by weight or less and 5% by weight or more.

In the papermaking material for a natural fiber molded article according to the present invention, a thermodegradable or thermoplastic biodegradable resin may be used as the binder resin.

Furthermore, in the method for producing a papermaking material for a natural fiber molded article according to the present invention, the natural fiber occupying a content exceeding 50% by weight in the natural fiber molded article is obtained by intertwining each of the natural fibers during the heat compression molding in the subsequent step. Dispersed water dispersed with the binder resin powder bonding the bonding points is evenly discharged into the papermaking tank where the papermaking mesh is arranged and temporarily stored on the papermaking net, from the lower part of the papermaking tank. By draining the paper, the natural fibers are entangled with each other by the papermaking net, and then the papermaking material drawn on the papermaking net is dehydrated and dried to obtain the papermaking material, The natural fiber is composed of a first natural fiber having a relatively long fiber that occupies 70 to 80% by weight and a second natural fiber having a relatively short fiber that occupies the remaining 10 to 15% by weight. The second The natural fibers are positioned so as to fill the gaps between the first natural fibers entangled with each other in the papermaking material, and the binder resin powder having a particle size of 1 to 100 μm is not discharged in the drainage during the drainage. It works effectively to keep it in place.

  According to the papermaking material of the natural fiber molded product and the method for producing the same according to the present invention, the natural fiber in the molded product occupies a content exceeding 50% by weight, so that the amount of petroleum-derived resin used can be suppressed. It can provide natural fiber molded products that are lightweight, inexpensive and friendly to the natural environment.

  In addition, the paper product that is drawn on the paper net is made in a state where the natural fibers are intertwined with each other in three dimensions, and the natural fibers are intertwined during the subsequent heat compression molding by the binder resin powder attached around the fibers. In addition, since each joint point is coupled, the natural fiber molded product manufactured from the papermaking material can have high mechanical strength against bending and pulling in any direction.

  Furthermore, as described above, the molded product containing a large amount of natural fibers has an effect that the natural fibers have a surface property that can be seen on the appearance, and can appeal to the viewer that the product is friendly to the natural environment.

It is a whole schematic block diagram of a papermaking apparatus. It is a perspective view of a dispersion | distribution nozzle. It is a top view which shows the bottom face of a dispersion | distribution nozzle. It is a top view which shows the bottom face of a water storage tank. It is a top view which shows the on-off valve movably mounted on the bottom face of the water storage tank shown to FIG. 3A. It is process drawing which shows each process of a papermaking method in order. It is a figure which shows the motion of the dispersion water which fell to the upper papermaking tank from the water storage tank bottom face. It is a figure which shows a mode that the piled paper products are piled up in multiple steps with a paper net, and press-dehydrated. It is the partial side view of the papermaking thing or papermaking material, and its partial enlarged view. It is a figure which shows the surface property in which the natural fiber has appeared in the external appearance of a natural fiber molded article. It is a sectional side view showing a papermaking net and a papermaking holder for obtaining a papermaking product and papermaking material having a three-dimensional shape.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like.

  FIG. 1 is a schematic configuration diagram showing a papermaking apparatus 10 for producing a papermaking material for a natural fiber molded product according to an embodiment of the present invention. The paper making apparatus 10 disperses the first and second natural fibers 2 and 4 (see FIG. 7), which are measured raw materials, into a predetermined amount of water while being dispersed by stirring with a motor-driven stirrer 12. A tank 16, an additive tank 22 containing an additive 18 such as a nonionic surfactant and having a motor-driven stirrer 20, and a supply from the dispersion tank 16 and the additive tank 22 by opening the on-off valves 24 and 26, respectively. The dispersion tank 14 containing the dispersion water 14 and the additive 18 to be stirred and mixed by the motor driven stirrer 28 and the dispersion water 32 generated by adding the additive 18 to the dispersion water 14 in the mixing tank 30 A storage tank 34 that is discharged from the mixing tank 30 and temporarily stored, an upper papermaking tank 36 and a lower papermaking tank 38 that receive and temporarily store the dispersed water 32 dropped below the water storage tank 34, and an upper papermaking tank 36 and a lower papermaking. 38, a papermaking holder 42 for placing and supporting the papermaking mesh 40, and water 44 provided in the bottom of the lower papermaking tank 38 and filled in the lower papermaking tank 38. The water stop valve 46 is mainly configured. The upper portions of the water storage tank 34, the upper papermaking tank 36, and the lower papermaking tank 38 are formed in, for example, a rectangular shape in plan view having a size of about 950 mm in length and width. However, each tank is not limited to the planar shape of the square tube or the above dimensions.

  A dispersion nozzle 52 is connected to the lower part of the mixing tank 30 through a communication pipe 50 that is opened and closed by a water stop valve 48. The water stop valve 48 is opened and closed by a motor, for example. As shown in the perspective view of FIG. 2A, the dispersion nozzle 52 is formed of a box having a size of about 150 mm in length and about 400 mm in width and having a substantially semicircular shape in side view. A large number of fountain holes 56 are formed on the bottom surface 54 of the dispersion nozzle 52 as shown in the bottom view of FIG. 2B. The fountain hole 56 is formed as an elliptical through hole having a major axis of about 40 mm and a minor axis of about 20 mm, for example, and the dispersed water 32 in the mixing tank 30 is uniformly discharged toward the entire bottom surface 58 of the water storage tank 34. The bottom surface 54 is appropriately arranged, for example, in a staggered pattern or a matrix pattern.

  As shown in the top view of FIG. 3A, a large number of drain holes 60 are formed in the bottom surface 58 of the water storage tank 34. On the other hand, a rectangular plate-shaped on-off valve 62 is slidably mounted on the bottom surface 58 of the water storage tank 34. As shown in the top view of FIG. 3B, the on-off valve 62 has a shape equivalent to the drain hole 60 on the bottom surface 58 of the water storage tank 34 and a plurality of communication holes 64 formed at corresponding positions. The drain hole 60 and the communication hole 64 are formed as long holes having a short diameter of about 5 mm and a long diameter of about 20 mm, and the on-off valve 62 is movable in the short diameter direction of the communication hole 64.

  A guide rod 66 and a drive rod 70 connected to a drive shaft of an actuator 68 such as an air cylinder protrude from both side surfaces of the on-off valve 62. The guide rod 66 and the drive rod 70 are provided so as to penetrate the both side wall surfaces of the water storage tank 34, and are supported by the water seal bearings 72 so as to be movable in the axial direction while preventing water leakage.

  The upper papermaking tank 36 is formed in a rectangular tube shape having an upper surface opening and a lower surface opening. When the dispersed water 32 is received from the mixing tank 30, a space 74 is formed above the papermaking net 40 in the tank. The one with the size to get is used.

  The net 40 is a mesh body of about 60 mesh made of stainless steel, for example. The netting holder 42 for placing and supporting the netting net 40 is made of a so-called punching metal, a synthetic resin plate, or the like, and a large number of water passage holes 76 are formed over the entire surface.

  In the papermaking apparatus 10, the peripheral edge of the bottom surface 58 of the water storage tank 34 and the upper opening peripheral edge of the upper papermaking tank 36 that are assembled so as to be separable in the vertical direction are sealed with a sealing member (not shown). Further, the lower opening opening peripheral part of the upper paper making tank 36 assembled to be vertically separable, the peripheral part of the paper making net 40, the peripheral part of the paper making holder 42, and the upper opening opening peripheral part of the lower paper making tank 38 are not shown. It is sealed with water by a member.

  The bottom of the lower papermaking tank 38 is connected to a water storage tank 80 via a connecting pipe 78 provided with a water stop valve 46. The water drained from the lower papermaking tank 38 and stored in the water storage tank 80 is sent from the return pipe 84 to the dispersion tank 16 by the drive of the pump 82 and reused. Further, when water is unnecessary, the water is discharged from the drain pipe 86 to the outside of the system.

Then, the manufacturing process of the papermaking raw material 1 for natural fiber molded articles (refer FIG. 7) using the papermaking apparatus 10 which consists of the said structure is demonstrated with reference to FIG. In this embodiment, a cellulose fiber produced from kenaf and a bundle thereof (hereinafter simply referred to as “kenaf”) are used as the first natural fiber having a relatively long fiber length, and the second fiber having a relatively short fiber length is used. An example in which cellulose pulp obtained by chemical treatment of wood chips as natural fibers (hereinafter referred to as “wood pulp”) and phenol resin powder, which is a thermosetting resin, is used as binder resin powder will be described. The raw material formulation used here is shown below in terms of% by weight in the final molded product.
(1) Kenaf: 70-80% by weight
(2) Wood pulp: 10-15% by weight
(3) Phenol resin powder: 5 to 20% by weight

  Here, the first natural fiber having a relatively long fiber length, in addition to kenaf, for example, using cellulose fiber obtained from bagasse, rice straw, straw, bamboo, weeds, etc., which are waste materials after squeezing sugarcane Also good. The second natural fiber having a relatively short fiber length is not limited to wood pulp, and the same type of natural fiber obtained by cutting the first natural fiber may be used, or any other natural fiber. It may be.

  Moreover, although the phenol resin which is a thermosetting resin is illustrated as a binder resin in the above, a furan resin, unsaturated polyester resin, diallyl phthalate resin, a polyurethane resin, an epoxy resin etc. are mentioned other than a phenol resin, for example. Furthermore, a thermoplastic resin may be used as the binder resin, and examples thereof include polypropylene resin, polyethylene resin, polyamide resin, polycarbonate resin, polybutylene terephthalate resin, polystyrene resin, acrylonitrile-styrene resin, and the like. Furthermore, if a biodegradable resin having thermosetting or thermoplastic properties (for example, lactic acid, polylactic acid, etc.) is used as the binder resin, the natural fiber molded product as the final product is completely decomposed and disappears in nature. It becomes possible and becomes extremely environmentally friendly.

  When the paper making process is started, the paper making apparatus 10 is configured in advance so that an air layer is not formed between the bottom of the lower paper making tank 38 and the paper screen holder 42 or the paper screen 40 with the water stop valve 46 closed. Water 44 is filled. Thereby, since the water separated from the dispersed water 32 can be smoothly passed through the water passage hole 76 of the mesh making holder 42, the state of the dispersed water 32 stored on the mesh making network 40 is not disturbed. In this case, if the lower part of the papermaking net holder 42 is not filled with water, the air in the lower papermaking tank 38 flows through the netting net holder 42 when the water separated from the dispersed water 32 flows down the water passage hole 76. The dispersion water 32 that has been allowed to stand up in the upper papermaking tank 36 is stirred up through the holes 76 and the papermaking net 40, and a hollow portion of a trace of air passing through the finished papermaking material is generated. The wood pulp 4 (see FIG. 7) is not preferable because it is aligned in the direction of the cavity.

  As a first step of the paper making process, a predetermined amount of water is weighed and introduced into the dispersion tank 16 with the on-off valve 24 closed, and raw materials kenaf 2, wood pulp 4 and phenol resin powder 6 (FIG. 7). Are measured according to the above formulation so that the total weight of the raw materials (1) to (3) is about 5% by weight with respect to the input amount of water (100% by weight) Then, by stirring with the motor-driven stirrer 12, the dispersed water 14 in which the raw materials are uniformly dispersed is generated (step S10). In addition, in the additive tank 22 with the on-off valve 26 closed, 0.08% by weight of a nonionic surfactant (additive) 18, for example, trade name of Sumitomo Seika Co., Ltd., based on the total weight of the raw materials. “PEO-PF” containing polyethylene oxide as a main component is added and stirred with the motor-driven stirrer 20 (step S10).

  When the dispersion water 14 is generated and the nonionic surfactant 18 is ready, the on-off valves 24 and 26 are opened and the dispersion water 14 and the nonionic water are transferred from the dispersion tank 16 and the additive tank 22 to the mixing tank 30. Surfactant 18 is added and mixed (step S12). At this time, by operating the motor-driven stirrer 28 for a while, the dispersion water 14 containing the raw materials and the nonionic surfactant 18 are uniformly mixed in the mixing tank 30 to generate the dispersion water 32.

  In the dispersed water 32 in the mixing tank 30, the low concentration (0.08 wt%) nonionic surfactant functions as a polymer flocculant. Due to the function of this nonionic surfactant, the kenaf 2 and the wood pulp 4 are intertwined with each other in a state in which the phenol resin powder 6 is adhered to the fiber surface, and a large number of flocs F (Fig. 5), and the floc F floats in the dispersed water 32 and is stably dispersed. Subsequently, the water stop valve 48 is opened, so that the dispersed water 32 in the mixing tank 30 is evenly sprayed and stored from the fountain hole 56 of the dispersion nozzle 52 over the entire surface of the water storage tank 34 (step S14).

  Then, as shown in FIG. 5, while the floc F in the dispersed water 32 is drifting in the water (about several seconds), the actuator 68 drives the on-off valve 62 in the direction of arrow B to remove all of the water tank 34. The water holes 60 are simultaneously opened to release the dispersed water 32 (step S16). At this time, it is desirable to drop the dispersed water 32 almost uniformly over the entire bottom surface 58 of the water storage tank 34. At the same time, a part of the water may be extracted from the upper part of the water storage tank 34. In addition, if the disperse water 32 is left for a long time and the floc F settles in the water tank 34, the kenaf 2 and the wood pulp 4 forming the floc F will be entangled in a certain direction. There arises a disadvantage that the thickness of the resulting papermaking material 1 is not uniform.

  The dispersed water 32 dropped from the drain hole 60 of the water storage tank 34 is received and stored above the papermaking net 40 in the upper papermaking tank 36 through the space 74. Then, as the storage amount of the dispersed water 32 gradually increases, the vertical flow spiral flow 90 is generated by the momentum of the falling flow 88 falling through the space 74, and the natural fibers 2, 4 in the floc F, particularly The kenaf 2, which is a relatively long fiber, is randomly tangled in all three-dimensional directions, up, down, left, and right. Then, the dispersed water 32 temporarily stored in the upper papermaking tank 36 is allowed to stand for an appropriate time (step S18). As a result, the floc F sinks toward the papermaking net 40, and the natural fibers 2 and 4 are entangled with each other between the adjacent flocs F (see the partially enlarged view C in FIG. 7).

  Thereafter, water is drained from the lower papermaking tank 38 by opening the water stop valve 46 (step S20). Then, the natural fibers 2 and 4 in a state where the phenol resin powder 6 adheres to the periphery of the fiber are picked up by the paper making net 40 disposed between the upper paper making tank 36 and the lower paper making tank 38, A papermaking 96 (see FIG. 7) is formed (step S22).

  The above draining operation is preferably performed evenly from all the water passage holes 76 when the surface of the dispersed water 32 in the upper papermaking tank 36 is leveled. Incidentally, it is not preferable to drain water when the water surface of the dispersed water 32 on the papermaking net 40 is undulating because the upper surface of the papermaking product on the papermaking net 40 is undulated when viewed from the side.

  At the time of draining, the phenol resin powder 6 is firmly adsorbed on the surfaces of the kenaf 2 and the wood pulp 4 due to the function of the nonionic surfactant. Here, when wood pulp 4 of relatively short fibers is mixed as a raw material as in this embodiment, the wood pulp 4 is positioned so as to fill the gap between the entangled kenaf 2, so that only the kenaf 2 is natural. Compared to the case of using the fiber raw material, the phenol resin powder 6 is more effective in keeping it in the papermaking product without draining it together with draining water. However, even with only the phenol resin powder 6 adhering to the relatively long natural fibers such as kenaf 2, the binder effect of binding the natural fibers entangled with each other in each molding point in the molding step by the subsequent heat compression is obtained. Therefore, natural fibers having relatively short fibers can be omitted from the raw material.

  After draining as described above, the upper papermaking tank 36 is lifted by a lift mechanism (not shown) such as an air cylinder and separated from the lower papermaking tank 38. Then, the papermaking 96 containing a large amount of water (water content = about 85% by weight) is removed from the lower papermaking tank 38 with the papermaking mesh 40 attached. The steps S10 to S22 so far are performed at normal temperature and normal pressure.

  As shown in FIG. 6, the papermaking 96 and the papermaking net 40 removed from the lower papermaking tank 38 are stacked in a plurality of stages on the press stand 92 and are depressurized and dehydrated by the press plate 94 ( Step S24). After press dewatering, the papermaking 96 can be easily peeled off from the papermaking net 40. Then, the press-dehydrated paper product 96 is dried at an appropriate temperature and time (for example, about 110 ° C. for 90 minutes) (step S26), thereby forming a natural fiber molded product that forms a sheet as shown in FIG. Papermaking material 1 is completed.

  The papermaking material 1 thus manufactured is molded into a two-dimensional or three-dimensional molded product by compression molding at a high temperature of, for example, about 200 ° C. in a subsequent heat compression process. (S28). During the heat compression molding, the phenol resin powder 6 adhering to the natural fibers 2 and 4 is once melted and then cured to form a three-dimensional network structure with extremely high mechanical strength, and entangled with each other. Natural fibers 2 and 4 are firmly bonded at each joint point. As a result, the finished molded product has extremely high mechanical strength against external forces such as bending and pulling in any direction. Such natural fiber molded products can be used in a wide range of fields such as automobile interior parts, body parts, building materials, furniture materials, and machine parts.

  According to the papermaking material 1 of the natural fiber molded product manufactured as described above, the content of the natural fiber composed of kenaf 2 and wood pulp 4 in the final molded product is 80 to 95% by weight. Thus, the amount of petroleum-derived resin used can be significantly reduced compared to conventional FRP, etc., and it is lightweight, inexpensive, and is composed of natural fibers that are mostly biodegradable even when discarded. Therefore, it is possible to provide natural fiber molded products that are friendly to the natural environment.

  Further, the paper product 96 picked up on the paper screen 40 is made in a state where the natural fibers 2 and 4 are three-dimensionally entangled with each other, and is heated and compressed in the subsequent step by the phenol resin powder 6 attached around the fiber. Since each of the intertwined joints of the natural fibers 2 and 4 is firmly bonded at the time of molding, the natural fiber molded product manufactured from the papermaking material 1 has high mechanical strength against external forces such as bending and pulling in any direction. Can have strength.

  Furthermore, as shown in FIG. 8, the molded product containing a large amount of natural fibers 2 and 4 as described above has a surface property that allows natural fibers (here, kenaf 2) to be seen on the outside. It also has the effect of appealing that it is a product that is friendly to the natural environment.

  Although one embodiment according to the present invention has been sufficiently described above, the present invention is not limited to the above embodiment, and various changes and improvements can be made.

  For example, in the above embodiment, the papermaking is performed using the papermaking net 40 and the papermaking holder 42 each having a flat two-dimensional shape, but the papermaking mesh 40a and the papermaking holder 42a having the shapes shown in FIG. 9 are used. Then, it becomes possible to produce a three-dimensionally shaped paper product 96a having a concave portion 98 that is depressed downward, and consequently, it is possible to produce a three-dimensionally shaped paper material 1.

  Moreover, in the said embodiment, although content of the natural fiber comprised with kenaf and wood pulp was demonstrated as 80 to 95 weight%, and content of the binder resin illustrated with a phenol resin powder was 5 to 20 weight%, It is not limited to this. For example, the content of the natural fiber may be 70% by weight or more and less than 100% by weight, and the content of the binder resin may be 30% by weight or less and more than 0% by weight. Although it exists, the same effect as the said embodiment can be acquired. If this is expanded, it can be said that the natural fiber in the papermaking material for natural fiber molded article may be configured so that the natural fiber occupies more than the resin content derived from petroleum, that is, the content exceeding 50% by weight.

  Next, another embodiment will be described. In this embodiment, natural fiber as a raw material is the same as that in the above embodiment, and a papermaking material 1 is manufactured using a thermoplastic resin such as polybutylene terephthalate resin and polystyrene resin as a binder resin powder. An example in which a natural fiber molded article having a desired shape is finished by cold press molding will be described.

  In this embodiment, the weight ratio of the binder resin in the final molded product after cold press molding is preferably 5 to 20% by weight when the final molded product is applied to a product in which weight reduction is important. . This is because if the binder resin is less than 5% by weight, it is difficult to obtain sufficient bonding between natural fibers in the final molded product, while if it exceeds 20% by weight, the final molded product is increased in weight and cost.

  In the paper making process, when using a fibrillated one of the first natural fibers that are long fibers in order to make the natural fibers easily entangle with each other, a larger amount is within the range of 5 to 20% by weight. It is more preferable to select the amount of the binder resin in order to increase the bond strength between natural fibers. Moreover, it is preferable that the binder resin powder used for a raw material is 1-100 micrometers in particle size. Powders with a diameter smaller than 1 μm tend to agglomerate and become difficult to handle. On the other hand, when the diameter is larger than 100 μm, the binder resin powder does not adhere to the surroundings of the natural fibers during the paper making process and easily precipitates in the water tank. Because it becomes.

  Using the raw materials as described above, a papermaking material of a natural fiber molded product was manufactured by the papermaking process described above with reference to FIG. Then, using this papermaking material with an infrared heater or the like, the binder resin is sufficiently softened and heated to a temperature at which natural fibers can be bonded to each other, for example, 230 to 270 ° C., and then cold-molded or cold-molded at room temperature. Press molding is performed to finish a natural fiber molded product which is a final molded product having a desired shape. In addition, you may perform cold press molding in inert gas atmosphere, such as nitrogen, as needed.

  The cold press molding in this embodiment is not limited to once, and can be performed a plurality of times by reheating. This is because the first natural fibers, which are relatively long fibers, are three-dimensionally entangled with each other, so that the natural fibers constituting the papermaking material 1 are separated even when the resin is softened by heating and the binding force is reduced. This is because it will not be lost. For this reason, the final precision of the desired shape can be finished by performing press molding a plurality of times while sequentially increasing the mold accuracy for one papermaking material 1.

  Further, in cold press molding, a high density portion may be formed by partially applying at least one of the number of times of pressing and the pressing pressure to one papermaking material 1. The high-density part formed in this way has higher mechanical strength than other low-density parts, so the high-density part is fixed when the final molded product is bolted to another member. It is suitable for use as a part.

  In addition, conventionally, by adding a foaming agent, the entire foam was foamed during molding and the density was lowered to give cushioning properties to the resin molded product. However, in the papermaking material of this embodiment, the binder resin softens when heated. By doing so, the natural fiber swells in the thickness direction of the molded product by a restoring force due to its own elasticity, so that there is an advantage that cushioning properties are imparted to the molded product without using a foaming agent.

  In the present embodiment, it has been described that the weight ratio of the binder resin is preferably 5 to 20% by weight when weight reduction is important for the final molded product, but is not limited thereto. For example, the weight ratio of the binder resin to the final molded product after cold press molding is 20 to 70 wt., Preferably 30 to 70 wt.% When the final molded product is applied to a product that emphasizes flatness rather than weight reduction. % Is preferable. At this time, even when the weight ratio of the binder resin occupies the majority, it is possible to expect the reinforcing effect of the molded product by the natural fibers that are formed and bonded in a state of being entangled three-dimensionally.

  By the way, the papermaking material for natural fiber molded products is made by using the papermaking method similar to the above, using only the relatively long cellulose fibers obtained from bagasse and their bundles as raw materials (ie, bagasse 100% by weight). Then, when the papermaking material obtained by dehydrating and drying it was heat compression molded, it was confirmed that it could be molded without using a binder resin. This is considered to be because bagasse fibers that are intertwined with each other by the resin component that has oozed out of the bagasse itself at the time of molding are combined. However, since the properties such as mechanical strength are inferior to those of the natural fiber molded product containing the binder resin as in the above-described embodiment, it is preferably used for a component or product having a relatively small acting load and external force.

  1 Natural fiber molding material, 2 Kenaf (first natural fiber), 4 Wood pulp (second natural fiber), 6 Phenol resin powder (binder resin powder), 10 Paper making machine, 12, 20, 28 Motor Drive stirrer, 14 Dispersed water, 16 Dispersion tank, 18 Nonionic surfactant, 22 Additive tank, 24, 26 On-off valve, 30 Mixing tank, 32 Dispersed water, 34 Storage tank, 36 Upper papermaking tank, 38 Lower papermaking tank , 40, 40a paper making net, 42, 42a paper making net holder, 44 water, 46, 48 water stop valve, 50 communication pipe, 52 dispersion nozzle, 56 fountain hole, 58 water tank bottom, 60 water drain hole, 62 open / close valve, 64 communication holes, 66 guide rods, 68 actuators, 70 drive rods, 72 water seal bearings, 74 spaces, 76 water communication holes, 78 connection pipes, 80 water storage tanks, 82 pumps 84 return pipe, 86 drain pipe, 88 falling stream 90 spiral flow, 92 press table, 94 press plate, 96, 96a paper product, F floc.

Claims (14)

Dispersed water in which natural fibers with binder resin powder adhered around the fibers are dispersed evenly in the papermaking tank where the papermaking mesh is disposed and temporarily stored on the papermaking net, and the lower part of the papermaking tank. The natural fibers are tangled with each other by the paper making by draining from the paper, and then the paper made on the paper making is dehydrated and dried to make a natural fiber molded product. Material,
The natural fiber occupies a content of more than 50% by weight in the molded product, and the binder resin powder binds the entangled natural fibers to each other at each joining point during a subsequent heat compression molding,
The natural fiber is composed of a first natural fiber having a relatively long fiber that occupies 70 to 80% by weight and a second natural fiber having a relatively short fiber that occupies the remaining 10 to 15% by weight. The second natural fibers are positioned so as to fill the gaps between the first natural fibers entangled with each other in the papermaking material, and the binder resin powder having a particle size of 1 to 100 μm is caused to flow out during the drainage. A papermaking material for natural fiber molded products, which functions effectively to be kept in the paperwork without being damaged. In the papermaking material of the natural fiber molded product according to claim 1,
The content of the natural fiber in the molded product is 70% by weight or more and less than 100% by weight, and the content of the binder resin in the molded product is 30% by weight or less and more than 0% by weight. Papermaking material for natural fiber molded products. In the papermaking material of the natural fiber molded product according to claim 2,
The content of the natural fiber in the molded product is 80% by weight or more and 95% by weight or less, and the content of the binder resin in the molded product is 20% by weight or less and 5% by weight or more. Natural paper molding material. In the papermaking material of the natural fiber molded article according to any one of claims 1 to 3,
A papermaking material for a natural fiber molded article, wherein the binder resin is a thermodegradable or thermoplastic biodegradable resin. In the papermaking material of the natural fiber molded article according to any one of claims 1 to 4,
The first natural fiber is a cellulose fiber obtained from at least one of kenaf, bagasse, rice straw, and wheat straw, and the second natural fiber is wood pulp. Material. Dispersion in which natural fiber occupying a content exceeding 50% by weight in a natural fiber molded product is dispersed in a state in which a binder resin powder that binds each of the intertwined joint points of the natural fiber is attached at the time of subsequent heat compression molding Water is evenly discharged into the papermaking tank where the papermaking net is arranged, temporarily stored on the papermaking net, and drained from the lower part of the papermaking tank, so that the natural fibers are intertwined with each other by the papermaking net. The papermaking material is obtained by dewatering and drying the papermaking product, and then the papermaking product on the papermaking net,
The natural fiber is composed of a first natural fiber having a relatively long fiber that occupies 70 to 80% by weight and a second natural fiber having a relatively short fiber that occupies the remaining 10 to 15% by weight. The second natural fibers are positioned so as to fill the gaps between the first natural fibers entangled with each other in the papermaking material, and the binder resin powder having a particle size of 1 to 100 μm is caused to flow out during the drainage. A method for producing a papermaking material for a natural fiber molded article, which functions effectively to keep it in the papermaking product. In the manufacturing method of the papermaking raw material for natural fiber molded articles of Claim 6,
The content of the natural fiber in the molded product is 70% by weight or more and less than 100% by weight, and the content of the binder resin in the molded product is 30% by weight or less and more than 0% by weight. A method for producing a papermaking material for natural fiber molded products. In the manufacturing method of the papermaking raw material for natural fiber molded articles of Claim 7,
The content of the natural fiber in the molded product is 80% by weight or more and 95% by weight or less, and the content of the binder resin in the molded product is 20% by weight or less and 5% by weight or more. A method for producing a papermaking material for natural fiber molded products. In the manufacturing method of the papermaking raw material for natural fiber molded articles of any one of Claim 6 to 8 ,
A biodegradable resin having thermosetting or thermoplasticity is used as the binder resin, a method for producing a papermaking material for natural fiber molded products. In the manufacturing method of the papermaking raw material for natural fiber molded articles of any one of Claim 6 to 9,
The first natural fiber is a cellulose fiber obtained from at least one of kenaf, bagasse, rice straw, and wheat straw, and the second natural fiber is wood pulp. Material manufacturing method. A natural fiber composed of a paper product made of natural fibers drawn by a paper net in a state where the fibers are intertwined with each other, and a binder resin powder adhered around the natural fiber in the paper making process of the paper product A papermaking material for molded articles,
The natural fiber is composed of a first natural fiber having a relatively long fiber that occupies 70 to 80% by weight and a second natural fiber having a relatively short fiber that occupies the remaining 10 to 15% by weight. The second natural fiber is positioned so as to fill a gap between the first natural fibers entangled with each other in the papermaking material, and a binder resin powder having a particle size of 1 to 100 μm is added to the water during the papermaking process. It functions effectively to keep it in the paperwork without spilling along with it,
The binder resin is a thermoplastic resin, and the natural fibers entangled with each other by being cold press molded after being heated to a predetermined temperature are bound together by the binder resin, and the cold press molding is performed one or more times. A papermaking material for a natural fiber molded product, which is finished into a natural fiber molded product of a desired shape. In the papermaking material of the natural fiber molded product according to claim 11,
A natural fiber characterized in that a high density portion is formed in a natural fiber molded article by applying at least one of the number of times of pressing and the pressing pressure to one paper-making material partially at the time of cold press molding. Papermaking material for molded products. In the papermaking material of the natural fiber molded product according to claim 11,
When the natural fiber molded product after the press molding is applied to a product with an emphasis on weight reduction, the content of the binder resin in the molded product is 5 to 20% by weight. Material. In papermaking material natural fiber molded article according to any one of claims 11 to 1 3,
A papermaking material for a natural fiber molded article, wherein the binder resin is a thermodegradable or thermoplastic biodegradable resin.

Images