JP2017048475A - Fiber substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber substrate having reduced weight and improved rigidity.SOLUTION: A fiber substrate 10 comprises natural fiber 11 and synthetic resin-containing hollow fiber 13, and these fiber components are combined with a binder 15 made of resin. Preferably the content of the natural fiber 11 is 40 to 60 mass%, the content of the resin is 25 to 55 mass%, and the content of the hollow fiber 13 is 5 to 15 mass%, relative to 100 mass% of the fiber substrate 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber base material that achieves both weight reduction and improved rigidity. The fiber base material of the present invention is preferably used in the fields of vehicles, houses, daily necessities and the like.

BACKGROUND ART A fiber base material obtained by binding a large number of fibers including natural fibers with a binder is widely used from the viewpoint of the environment and applied in various industries.
For example, the following techniques are known for base materials for automobile interior parts. Patent Document 1 has a structure in which plant fibers are bound by a thermoplastic resin, and the plant fiber is 30 to 95% by mass when the total of the plant fiber and the thermoplastic resin is 100% by mass. A method for producing the contained vegetable fiber composite is disclosed. Patent Document 2 discloses a fiber layered body in which the blending ratio of natural fibers (such as kenaf fibers) and thermoplastic resins (such as polypropylene) gradually changes in the thickness direction.

JP 2009-234129 A JP 2002-105824 A

In the case of using a fiber base material containing a fiber material of the base material as a base material for interior parts of an automobile, further weight reduction of the base material is required in order to improve the fuel efficiency performance of the automobile. However, while it is possible to reduce the weight of the base material by reducing the basis weight of the fiber base material, as is apparent from the description of Patent Document 1, when the basis weight of the vegetable fiber composite material is reduced, the maximum bending load is reduced. Tend to decrease. Therefore, there has been a demand for a fiber base material that can reduce the basis weight while ensuring rigidity.
An object of the present invention is to provide a fiber base material in which weight reduction and improvement in rigidity are compatible.

The present inventors use natural fibers and hollow fibers having pores formed inside a cylindrical main body containing a thermoplastic resin and having a specific gravity smaller than that of natural fibers. The knowledge that the problem was solved was acquired.
The present invention is shown below.
(1) A fiber base material containing natural fibers and a resin serving as a binder, wherein the fiber base material contains hollow fibers containing a synthetic resin.
(2) The fiber substrate according to (1), wherein the fiber substrate is plate-shaped, and the content ratio of the resin, the natural fiber, and the hollow fiber is gradually changed in the thickness direction.
(3) The fiber base is plate-shaped, a central region mainly including the hollow fiber, an intermediate region mainly including the natural fiber located on both sides of the central region, and an outside of the intermediate region A surface region mainly composed of the resin located on a side surface, and the content ratio of the hollow fiber, the natural fiber, and the resin gradually changes in the thickness direction from the central region toward the surface region. The fiber substrate according to (1) above.
(4) When the said fiber base material is 100 mass%, content of the said natural fiber is 40-60 mass%, content of the said resin is 25-55 mass%, content of the said hollow fiber The fiber substrate according to any one of (1) to (3), wherein the amount is 5 to 15% by mass.
(5) The fiber substrate according to any one of (1) to (4), wherein the resin includes a thermoplastic resin.
(6) The fiber substrate according to any one of (1) to (5), wherein the basis weight is 0.5 to 1.0 kg / m ² .

  According to the fiber base material of the present invention, by combining natural fibers and hollow fibers, not only the weight of the base material can be reduced, but also rigidity superior to that of natural fibers alone can be obtained.

In the following, non-limiting examples of exemplary embodiments according to the present invention will be given and explained further in the detailed description with reference to the mentioned drawings, wherein like reference numerals are Similar parts are shown throughout the figure.
It is typical sectional drawing which shows one example of a plate-shaped base material as a fiber base material of this invention. It is typical sectional drawing which shows the other example of a plate-shaped base material as a fiber base material of this invention. It is typical sectional drawing which shows the other example of a plate-shaped base material as a fiber base material of this invention. It is typical sectional drawing which shows the other example of a plate-shaped base material as a fiber base material of this invention. It is a graph which shows the evaluation result of the rigidity in [Example].

  The items shown here are for illustrative purposes and exemplary embodiments of the present invention, and are the most effective and easy-to-understand explanations of the principles and conceptual features of the present invention. It is stated for the purpose of providing what seems to be. In this respect, it is not intended to illustrate the structural details of the present invention beyond what is necessary for a fundamental understanding of the present invention. It will be clear to those skilled in the art how it is actually implemented.

In the present specification, “mainly” expressing the content ratio of a specific component is preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more with respect to the object. Means that The unit is mass% or volume%.
The length of the fiber (fiber length) means the entire length regardless of the shape, and the outer diameter (fiber diameter) means the maximum diameter at a position corresponding to half the fiber length. These are lengths measured by an optical microscope or the like, and the average value is a value calculated for 200 fibers.

  The present invention is a fiber base material containing natural fibers and hollow fibers containing a synthetic resin, and is an integrated product in which a large number of contained fibers are bound by a binding material made of a resin.

  The natural fiber is a fiber derived from a plant or an animal. In the present invention, a fiber in which plant fiber and animal fiber are combined may be used.

  The natural fiber according to the present invention preferably contains a vegetable fiber.

The plant fiber may include fibers derived from stems, stems, branches, leaves, roots, etc. in plants as they are, and these are processed by heat treatment, drying treatment, pulverization treatment, chemical treatment, etc. Also good.
In the present invention, preferred plant fibers are kenaf, jute hemp, manila hemp, sisal hemp, cocoon, cocoon, cocoon, banana, pineapple, coconut, corn, sugar cane, bagasse, palm, papyrus, cocoon, esparto, surabigrass, wheat, rice It is a linear fibrous body derived from bamboo, conifers (cedar, firewood, etc.), hardwoods, cotton and the like. Among these, the mallow is a plant that has a woody stem, is an extremely fast growing annual plant, has an excellent carbon dioxide absorption, contributes to reducing the amount of carbon dioxide in the atmosphere, effective use of forest resources, etc. Particularly preferred is a linear fiber body (kenaf fiber) derived from kenaf. Examples of the kenaf include hibiscus cannabinus and hibiscus sabdariffa in scientific names, and red sesame, cuban kenaf, western hemp, taykenaf, mesta, bimli, ambari and bombay hemp in common names.

  As the above-mentioned animal fibers, human hair, pigs, sheep, goats, horses, deer, rabbits, rabbits, rabbits, etc. may be included as they are, and these include chemical treatment, heat treatment, drying treatment, grinding treatment, etc. May be processed.

  The natural fiber is usually solid, and its length (fiber length) and outer diameter (fiber diameter) are not particularly limited. The upper limit of the fiber length is preferably 100 mm. In addition, the average value of the fiber length is preferably 50 to 90 mm, and more preferably 60 to 80 mm. The upper limit of the fiber diameter is preferably 150 μm. The average fiber diameter is preferably 70 to 110 μm, more preferably 85 to 100 μm.

  The shape of the natural fiber contained in the fiber base material of the present invention is not particularly limited. The shape in the length direction can be a straight line, a broken line, a curved line, a spiral, or a deformed form thereof. The outer shape of the cross section may be a circle, an ellipse, a polygon, or a deformed shape thereof.

  The hollow fiber is a fiber having pores or hollow portions (hereinafter referred to as “pores” together) inside a main body portion containing a synthetic resin, and the pores penetrate from one end side to the other end side. , Fibers in which pores are intermittent, fibers in which pores are continuously distributed, and the like.

The synthetic resin constituting the hollow fiber main body is not particularly limited, and may be either a thermoplastic resin or a cured resin. The main body portion may be made of only a synthetic resin, and further contains additives such as an antioxidant, a plasticizer, an antistatic agent, a flame retardant, an antibacterial agent, an antifungal agent, and a colorant. But you can.
Examples of the hollow fibers include polyester fibers, polyarylate fibers, polyamide fibers, polyolefin fibers, acetate fibers, polysulfone fibers, and cellulose fibers having pores. These hollow fibers may be contained alone or in combination of two or more in the fiber base material of the present invention.
As the hollow fiber according to the present invention, a polyester fiber, a polyarylate fiber, a polyamide fiber or the like having pores inside the main body portion containing the thermoplastic resin is preferable.

  The length (fiber length) and outer diameter (fiber diameter) of the hollow fiber are not particularly limited. The upper limit of the fiber length is usually 100 mm. In addition, the average value of the fiber length is preferably 10 mm or more, and more preferably 30 to 70 mm. The upper limit of the fiber diameter is usually 150 μm. In addition, the average value of the said fiber diameter becomes like this. Preferably it is 20-100 micrometers, More preferably, it is 25-80 micrometers.

The shape of the hollow fiber contained in the fiber base material of the present invention is particularly limited when the shape of the hollow fiber used in manufacturing the fiber base material is maintained as it is or when it is deformed by pressure or the like. Not. The shape in the length direction can be a regular shape such as a straight line, a polygonal line, a curved line, a spiral, or a deformed form thereof. Moreover, the external shape of a cross section can be made into circular, an ellipse, a polygon, or these deformation | transformation shapes.
Moreover, the porosity of the hollow fiber contained in the fiber base material of the present invention is preferably 15 to 80% by volume, more preferably 20 to 60% by volume, from the viewpoint of rigidity in the fiber base material of the present invention.

  The fiber base material of the present invention contains other fibers such as solid fibers containing synthetic resin, solid fibers made of inorganic materials or hollow fibers, and other components such as foamed particles and rubber particles, if necessary. But you can. The upper limit of the content in the case of containing other fibers or other components is usually 100 parts by mass when the content of the natural fiber is 100 parts by mass.

  The fiber base material of the present invention is mainly composed of natural fibers and hollow fibers, and all the fibers, particles and the like are bonded by a binding material even when other components are included. The main component of the binder is not particularly limited, but is preferably a thermoplastic resin and a cured resin, and particularly preferably a thermoplastic resin.

  The thermoplastic resin may be the same as or different from the synthetic resin (in the case of a thermoplastic resin) constituting the hollow fiber, and may be a polyolefin resin, a saturated polyester resin, an aromatic vinyl resin, an acrylic resin, Examples include polyacetal resins, polyvinyl alcohol resins, urethane resins, and modified products thereof. In the case of a modified product, acid modification, amino modification, epoxy modification and the like can be performed.

  Examples of the polyolefin resin include propylene polymers such as polypropylene and ethylene / propylene (random) copolymers; polyethylene and the like. The modified product is preferably an acid-modified product (acid) such as maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride or the like having a carboxyl group or a derivative thereof (an acid anhydride group). Modified polyolefin).

  The saturated polyester resin is not particularly limited, and may be any of an aliphatic polyester resin, an alicyclic polyester resin, and an aromatic polyester resin. Of these, aliphatic polyester resins are preferred, for example, homopolymers of hydroxycarboxylic acids such as lactic acid, malic acid, glucose acid, 3-hydroxybutyric acid; and co-polymers using at least one of these hydroxycarboxylic acids. Hydroxycarboxylic acid polyesters such as polymers; polycaprolactone, caprolactone polyesters such as copolymers of at least one of the above hydroxycarboxylic acids and caprolactone; polybutylene succinate, polyethylene succinate, polybutylene adipate, etc. And dibasic acid polyesters.

The thermoplastic resin preferably has a melting point lower than the melting point or decomposition point of the synthetic resin constituting the hollow fiber. In this case, the temperature difference between the melting point of the thermoplastic resin and the melting point or decomposition point of the synthetic resin constituting the hollow fiber is preferably 30 ° C. or higher, more preferably 50 ° C. or higher. In addition, the upper limit of this temperature difference is 150 degreeC normally.
The thermoplastic resin is preferably a polyolefin resin, and more preferably a propylene polymer such as polypropylene or an ethylene / propylene copolymer, or a modification thereof, from the viewpoint of adhesiveness between natural fibers and hollow fibers. It is a thing. As the modified product, acid-modified polypropylene is preferable, and acid-modified polypropylene with maleic anhydride is particularly preferable.
In addition, when using the said polyolefin resin, it is preferable to use together non-modified resin and modified resin. The ratios of the non-modified resin and the modified resin at this time are preferably 80 to 99% by mass and 1 to 20% by mass, more preferably 85 to 98.5%, respectively, when the total of both is 100% by mass. % And 1.5 to 15% by mass, more preferably 90 to 97% by mass and 3 to 10% by mass.

  On the other hand, the cured resin may have a crosslinked structure or the like, and may be derived from an acrylic resin, a urethane resin, a vinyl ester resin, an unsaturated polyester resin, an epoxy resin, or the like.

  The binder may contain an antioxidant, a plasticizer, an antistatic agent, a flame retardant, an antibacterial agent, a fungicide, and the like in addition to the thermoplastic resin or the cured resin.

The content ratio of the natural fiber contained in the fiber base material of the present invention is preferably 40 to 60% by mass, more preferably 100% by mass when the fiber base material is 100% by mass without depending on the configuration of the fiber base material. Is 45-60 mass%, More preferably, it is 50-60 mass%.
The content ratio of the hollow fibers contained in the fiber base material of the present invention is preferably 5 to 15% by weight, more preferably, when the fiber base material is 100% by weight without depending on the configuration of the fiber base material. Is 5 to 14% by mass, more preferably 5 to 10% by mass.
The content ratio of the binder (resin) contained in the fiber base material of the present invention is not particularly limited, but from the viewpoint of shape stability and rigidity as an integrated product, when the fiber base material is 100% by mass, Preferably it is 25-55 mass%, More preferably, it is 26-50 mass%, More preferably, it is 30-45 mass%.

  In the fiber base material of the present invention, at least natural fibers and hollow fibers are bonded by a binder, and adjacent fibers are bonded by a binder as described above. In addition, although the manufacturing method of a fiber base material is mentioned later, depending on the method or the kind of hollow fiber, the hollow fiber with which the pores were filled with the binder may be included.

Basis weight of the fiber base material of the present invention, from the viewpoint of compatibility between improvement of weight reduction and rigidity, preferably 0.5~1.2kg / ^{m 2,} more preferably 0.55~1.0kg ^{/ m} 2, More preferably, it is 0.6-0.8 kg / m < ² >.

The shape of the fiber base material of the present invention can be a flat plate (FIGS. 1, 2, 3, 4), a curved plate, a block, a rod, an indeterminate shape, etc., depending on the purpose, application, etc. It is substantially a high density molded article. In the present invention, any shape has excellent rigidity. In the case of an article having a thin-walled fiber substrate or a thin-walled portion, the thickness of the thin-walled portion is preferably 1.5 mm or more. Need not be identical.
The orientation of the fiber contained in the fiber base material of the present invention is not particularly limited, and all the fibers may be oriented mainly in the length direction thereof or may be random. Moreover, the distribution form of a natural fiber and a hollow fiber is not specifically limited.
In the present invention, the natural fiber and the hollow fiber are uniformly distributed over the entire fiber base (hereinafter referred to as “first aspect”), and from one part of the fiber base to the other part. On the other hand, in any of the embodiments (hereinafter referred to as “second embodiment”) including a portion in which the ratio of the content of the natural fiber and the content of the hollow fiber is changed, the weight is reduced and the rigidity is excellent. Have In general, in a composite material containing a plurality of types of fibers, it is better that each fiber is uniformly distributed over the entire surface. However, in the present invention, natural fibers and hollow fibers are uniformly distributed. Even if it is a 2nd aspect which is not, it is excellent in rigidity.

Hereinafter, a plate-like substrate as a specific example of the fiber substrate of the present invention will be described.
The plate-like substrate having the configuration of the first aspect is shown in FIG. 1, for example. FIG. 1 is a cross-sectional view of a plate-like substrate 10 made of a flat plate that uniformly contains natural fibers 11 and hollow fibers 13 and in which the fibers are bonded together by a bonding material 15 made of resin. Although not shown in the figure, the plate-like substrate 10 of FIG. 1 may contain other fibers or other components. In this case, the other fibers or other components are made of resin (binding material) 15. , Natural fiber 11, hollow fiber 13 and the like. The binding material 15 made of resin normally enters the gaps between the fibers from the one surface side to the other surface side and binds the fibers, and the resin portion is formed in a continuous phase.
The thickness of the plate-like substrate 10 in FIG. 1 is preferably 1.5 to 6.0 mm, more preferably 1.8 to 4.0 mm, and still more preferably 2.3 to 3.5 mm from the viewpoint of rigidity. is there.

The plate-like substrate having the configuration of the second aspect is preferably a portion where the ratio of the content of the natural fiber and the content of the hollow fiber is changed in the thickness direction from the one surface side to the other surface side. In particular, a base material having an inclined structure in which the content ratios of resin (binding material), natural fiber, and hollow fiber are gradually changed from one surface side to the other surface side. .
The plate-like substrate of the second aspect is illustrated in FIGS.

2 substantially includes a resin layer 16 made of a resin (binding material) 15, a natural fiber layer 17 mainly composed of natural fibers 11, and a hollow fiber layer mainly composed of hollow fibers 13. 18 is a base material that is sequentially provided. In the natural fiber layer 17, adjacent natural fibers 11 are bonded together by a binder 15 made of resin, and in the hollow fiber layer 18, adjacent hollow fibers 13 are also bonded by a binder 15 made of resin. Has been. At the interface between the natural fiber layer 17 and the hollow fiber layer 18, adjacent natural fibers 11 and hollow fibers 13 are bonded together by a bonding material 15. The binding material 15 made of resin normally enters the gaps between the fibers from the one surface side to the other surface side and binds the fibers, and the resin portion is formed in a continuous phase.
The plate-like substrate of FIG. 2 can contain other fibers or other components, which may be contained uniformly or unevenly distributed.
The thickness of the plate-like substrate 10 in FIG. 2 is preferably 1.5 to 3.5 mm, more preferably 2.5 to 3.2 mm, and still more preferably 2.8 to 3.2 mm from the viewpoint of rigidity. is there.

3 is a hollow fiber layer (center region) 21 mainly including hollow fibers 13 and natural fibers mainly including natural fibers 11 located on both sides of this layer (center region) 21. A substrate provided with the layer 23. In the hollow fiber layer (center region) 21, adjacent hollow fibers 13 are bonded together by a binder 15 made of resin, and in the natural fiber layer 23, adjacent natural fibers 11 are bonded by resin. They are connected by a material 15. At the interface between the hollow fiber layer (center region) 21 and the natural fiber layer 23, the adjacent natural fibers 11 and the hollow fibers 13 are bonded by the bonding material 15. The binding material 15 made of resin normally enters the gaps between the fibers from the one surface side to the other surface side and binds the fibers, and the resin portion is formed in a continuous phase.
In the plate-like base material 10 of FIG. 3, since more excellent rigidity is obtained, the inclusion of the natural fibers 11 and the hollow fibers 13 from the hollow fiber layer (center region) 21 toward the natural fiber layer 23 on the surface layer side. It is preferable that the ratio is gradually changed.
The plate-like substrate of FIG. 3 can contain other fibers or other components, and these may be contained uniformly or unevenly distributed.
The thickness of the plate-like substrate 10 in FIG. 3 is preferably 1.5 to 3.5 mm, more preferably 2.5 to 3.2 mm, and still more preferably 2.8 to 3.2 mm from the viewpoint of rigidity. is there.

4 is positioned on both sides of the hollow fiber layer (center region) 21 mainly including the hollow fibers 13 and the hollow fiber layer (center region) 21, and the natural fibers 11 are mainly used. A natural fiber layer (intermediate region) 24, and a resin layer (surface region) 26 substantially consisting of a resin (binding material) 15 located outside the natural fiber layer (intermediate region) 24. It is a material. In the hollow fiber layer (center region) 21, adjacent hollow fibers 13 are bonded together by a binder 15 made of resin, and also in the natural fiber layer (intermediate region) 24, adjacent natural fibers 11 are Bonded by a bonding material 15 made of resin. At the interface between the hollow fiber layer (center region) 21 and the natural fiber layer (intermediate region) 24, the adjacent natural fibers 11 and hollow fibers 13 are bonded together by the bonding material 15. The binding material 15 made of resin normally enters the gaps between the fibers from the one surface side to the other surface side and binds the fibers, and the resin portion is formed in a continuous phase.
Also in the plate-like substrate 10 of FIG. 4, since more excellent rigidity is obtained, the natural fibers 11 and the hollow fibers 13 are directed from the hollow fiber layer (center region) 21 toward the natural fiber layer (intermediate region) 24. It is preferable that the content ratio is gradually changed.
The plate-like substrate of FIG. 4 can contain other fibers or other components, and these may be contained uniformly or unevenly distributed.
The thickness of the plate-like substrate 10 in FIG. 4 is preferably 1.5 to 3.5 mm, more preferably 2.5 to 3.2 mm, and still more preferably 2.8 to 3.2 mm from the viewpoint of rigidity. is there.

  As the plate-like substrate of the second embodiment, the plate-like substrates of FIGS. 3 and 4 are particularly preferable.

  The method for producing the fiber base material of the present invention is not particularly limited, and can be appropriately selected according to the shape, the layer configuration and the like. As described above, in the present invention, the fiber base material can have various shapes, but it is preferable to use a thermal bond method or a chemical bond method.

When manufacturing the plate-shaped base material 10 shown in FIG. 1 as a fiber base material of a 1st aspect, it can be set as the following methods.
(A1) A fiber made of a resin composition having a melting point lower than the melting point or decomposition point of the synthetic resin constituting the hollow fiber (heat fiber) After the resin fiber (heat-fusible resin fiber) is melted, the hollow fiber is hot-pressed at a temperature at which the fiber fiber is not melted and decomposed. // Method of molding while bonding adjacent fibers of hollow fiber with melt of resin fiber (heat-fusible resin fiber) (A2) After mixing natural fiber and hollow fiber, fiber mixture obtained A liquid binder composition, and then drying, heating, pressurizing, and the like, and forming the fibers while bonding adjacent fibers contained in the fiber mixture

As the fiber base material of the second aspect, a resin layer 16 substantially composed of a resin (binding material) 15, a natural fiber layer 17 mainly composed of natural fibers 11, and a hollow fiber layer 18 mainly composed of hollow fibers 13. In the embodiment of the plate-like base material 10 shown in FIG. 2, the ratio of the content of the natural fiber 11 and the content of the hollow fiber 13 gradually changed from the one surface side to the other surface side. When manufacturing the plate-shaped base material which consists of a plane plate which has an inclination structure, it can be set as the following method.
(B1) Resin fiber having a bonding action between fibers by melting and comprising a resin composition having a melting point lower than the melting point or decomposition point of the synthetic resin constituting the hollow fiber body (heat-fusible resin fiber) ) Only, and then deposited thereon so that the ratio of the content of natural fibers to the content of hollow fibers is gradually reduced to produce a fiber aggregate, then obtained The fiber assembly is heat-pressed at a temperature at which the resin fiber (heat-sealable resin fiber) melts while the heat-sealable resin fiber layer is the upper surface side, while the hollow fiber is not melted and decomposed. A method of forming fibers and / or hollow fibers adjacent to each other by a melt of resin fibers (heat-fusible resin fibers) (B2) A resin fiber having a bonding action between fibers by melting, Constructs hollow fiber body A fiber (heat-sealable resin fiber) having a melting point lower than the melting point or decomposition point of the synthetic resin, natural fiber, and hollow fiber, and at least the content of the natural fiber and the hollow fiber These were deposited to produce a fiber aggregate so that the ratio to the content gradually decreased and the resin fibers (heat-sealable resin fibers) were uniformly contained, and then obtained. The fiber aggregate is heated and pressed at a temperature at which the resin fibers (heat-bondable resin fibers) melt and the hollow fibers do not melt and decompose, and the adjacent fibers of the natural fibers and / or hollow fibers are resin fibers (heat (B3) A method of molding while being bonded by a melt of fusible resin fibers) (B3) Using natural fibers and hollow fibers, so that the ratio of the content of natural fibers and the content of hollow fibers gradually decreases These are deposited to create a fiber aggregate. Thereafter, a liquid binder composition is attached to the obtained fiber aggregate, and then drying, heating, pressing, etc. are performed to bond adjacent fibers contained in the fiber aggregate. how to

As a fiber base material of the second embodiment, a hollow fiber layer (center region) 21 mainly composed of hollow fibers 13 and a natural fiber mainly composed of natural fibers 11 located on both sides of the hollow fiber layer (center region) 21 In the embodiment of the plate-like substrate 10 shown in FIG. 3 including the fiber layer 23, the content ratios of the natural fiber and the hollow fiber gradually increase from the hollow fiber layer (center region) 21 toward the natural fiber layer 23 on the surface layer side. A flat plate having an inclined structure, or a hollow fiber layer (center region) 21 mainly composed of hollow fibers 13 and the both sides of the hollow fiber layer (center region) 21 and the natural fibers 11 A main layer (intermediate region) 24 and a resin layer (surface region) 26 substantially made of resin (binding material) 15 located outside the natural fiber layer (intermediate region) 24; 4, the hollow fiber layer ( When manufacturing a flat plate having an inclined structure in which the content ratios of the natural fibers 11 and the hollow fibers 13 are gradually changed from the core region 21 to the natural fiber layer (intermediate region) 24, the following method is used. Can do.
(C1) A fiber (bonding resin fiber having a melting point lower than the melting point or decomposition point of the synthetic resin constituting the hollow fiber main body part, which is a resin fiber having a bonding action between fibers by melting. ), Natural fiber, and hollow fiber, and at least the ratio of the content of the natural fiber and the content of the hollow fiber is gradually reduced, and the resin fiber (heat-fusible resin fiber) Are deposited so as to be uniformly contained, and then a fiber aggregate is produced. After that, the two fiber aggregates are laminated so that the layers having a high content of hollow fibers face each other to form a laminate, Subsequently, the laminate is heated and pressed to a temperature at which the resin fibers (heat-fusible resin fibers) are melted and the hollow fibers are not melted or decomposed, and the adjacent fibers of the natural fibers and / or hollow fibers are resin fibers. (Heat-fusion resin fiber) (C2) Resin fiber having a bonding action between fibers by melting, and comprising a resin composition having a melting point lower than the melting point or decomposition point of the synthetic resin constituting the main body of the hollow fiber After only the fibers (heat-fusible resin fibers) are deposited, the first fibers are deposited on the fibers so that the ratio of the content of natural fibers to the content of hollow fibers gradually decreases. On the other hand, a natural fiber and a hollow fiber are used without using resin fibers (heat-fusible resin fibers), and the ratio between the content of natural fibers and the content of hollow fibers is gradually increased. These are deposited so as to be smaller to produce a second fiber aggregate, and then the first fiber aggregate and the second fiber aggregate are stacked so that the layers having a high content of hollow fibers face each other. A laminate, and this laminate is then The resin fiber (heat-sealable resin fiber) melts while the product is in the upper layer side, while the hollow fiber is hot-pressed to a temperature at which it does not melt and decompose, and the adjacent fibers of the natural fiber and / or hollow fiber are Method of molding while bonding with melt of resin fiber (heat-fusible resin fiber) (C3) Melting point of synthetic resin constituting body of hollow fiber, which is a resin fiber having a binding action between fibers by melting Alternatively, after depositing only fibers (heat-sealable resin fibers) made of a resin composition having a melting point lower than the decomposition point, the ratio of the content of natural fibers and the content of hollow fibers gradually increases. These are deposited so as to be reduced to produce a first fiber aggregate, while only resin fibers (heat-fusible resin fibers) are deposited, and then the content of natural fibers and hollow fibers are deposited thereon. The ratio with the content of These are deposited to produce a third fiber aggregate, and then the first fiber aggregate and the third fiber aggregate are laminated to form a laminate so that the layers having a high content of hollow fibers are close to each other, Thereafter, the laminate is heated and pressed to a temperature at which the resin fibers (heat-fusible resin fibers) are melted while the first fiber aggregate is on the upper layer side, while the hollow fibers are not melted and decomposed. And / or a method of molding adjacent fibers of a hollow fiber with a melt of resin fibers (heat-fusible resin fibers) (C4) using natural fibers and hollow fibers, These are deposited so that the ratio with the content of the hollow fiber gradually decreases, and after obtaining the fiber aggregate, the two fiber aggregates are so that the layers with a high hollow fiber content ratio face each other. Overlay to make a laminate, then add liquid to this laminate How to a binder composition is deposited, dried, heated and subjected to pressurization and formed while binding the fibers to each other adjacent contained in stack

  In all the above methods, before the resin fibers (heat-bondable resin fibers) are melted and before the liquid mixture, fiber aggregate or laminate is brought into contact with the liquid binder composition, the fibers are preliminarily formed. Mixtures, fiber aggregates or laminates may be entangled. The entanglement method is not particularly limited, but needle punching is common.

The types of natural fibers used in all the above methods are as described above. When natural fibers are used, conventionally known pretreatments (for example, contact with an alkaline aqueous solution for removal of deposits or odor reduction, etc.) may be performed in advance.
The shape of the natural fiber is not particularly limited, and the shape in the length direction can be a straight line, a polygonal line, a curved line, a spiral, or the like. The cross-sectional outer shape can be circular, elliptical, polygonal, or the like.
The length (fiber length) of the natural fiber is preferably 10 to 150 mm, more preferably 30 to 100 mm, from the viewpoint of rigidity in the obtained fiber base material. Moreover, the outer diameter (fiber diameter) of the said natural fiber is 10-200 micrometers from a viewpoint of the rigidity in the fiber base material obtained, More preferably, it is 50-150 micrometers.

The constituent materials of the hollow fiber used in all the above methods are as described above. When using hollow fibers, conventionally known surface treatments (for example, oxidation treatment, roughening treatment, etc.) may be performed in advance. Further, the porosity is preferably 15 to 80% by volume, more preferably 20 to 60% by volume, from the viewpoint of rigidity in the obtained fiber base material.
The shape of the hollow fiber is not particularly limited, and the shape in the length direction can be linear, broken line, curved, spiral, or the like. The cross-sectional outer shape can be circular, elliptical, polygonal, or the like.
The length (fiber length) of the hollow fiber is preferably 10 mm or more, more preferably 10 to 150 mm, from the viewpoint of rigidity in the obtained fiber base material. Moreover, the outer diameter (fiber diameter) of the said hollow fiber is 10-300 micrometers from a viewpoint of the rigidity in the fiber base material obtained, More preferably, it is 20-150 micrometers.

Method (A1), (B1), (B2), (C1), (C2) and (Method for producing a plate-like fiber base material using natural fibers, hollow fibers and resin fibers (heat-fusible resin fibers) In C3), the temperature difference between the melting point or decomposition point of the synthetic resin constituting the hollow fiber main body and the melting point of the resin constituting the resin fiber (heat-fusible resin fiber) is such that the production of the fiber substrate is efficient. Therefore, it is preferably 30 ° C. or higher, more preferably 50 ° C. or higher. In addition, the upper limit of this temperature difference is 150 degreeC normally.
Moreover, the ratio of the usage-amount of a natural fiber, a hollow fiber, and a resin fiber (heat-fusible resin fiber), When these sum total is 100 mass%, Preferably it is 30-60 mass%, respectively 5-30. Mass% and 30-50 mass%.
In addition, when using the fiber mixture which consists of a natural fiber, a hollow fiber, and a resin fiber (heat-fusible resin fiber), the manufacturing method of this fiber mixture is not specifically limited, It is set as the method using a card machine, air raid, etc. be able to.

  The resin fibers (heat-fusible resin fibers) used in the above methods (A1), (B1), (B2), (C1), (C2) and (C3) may contain a thermoplastic resin or a curable resin. it can. Among these, a thermoplastic resin is preferable because the fiber base material is easy to manufacture. This thermoplastic resin may be the same as or different from the synthetic resin constituting the hollow fiber, but a polyolefin resin, a saturated polyester resin, an aromatic vinyl resin, an acrylic resin, a polyacetal resin, a polyvinyl alcohol resin, Urethane resins or their modified products are preferred. The thermoplastic resin contained in the resin fiber (heat-fusible resin fiber) may be only one type, or two or more types. A plurality of resin fibers (heat-bondable resin fibers) having different configurations may be used.

  The thermoplastic resin is preferably a polyolefin-based resin, and polypropylene, ethylene / propylene (random) copolymer are used from the viewpoint of adhesion between natural fibers, between hollow fibers, and between natural fibers and hollow fibers. Non-modified resins such as propylene polymers such as polymers, polyethylene, etc., and these resins can be converted to carboxyl groups or derivatives thereof (acid anhydride groups) such as maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, etc. An acid-modified product (acid-modified polyolefin) obtained by modification with a compound having (

As described above, the thermoplastic resin contained in the resin fiber (heat-fusible resin fiber) may be two or more kinds, and includes, for example, a non-modified polyolefin resin and a modified resin. Resin fibers (heat-fusible resin fibers) can be used, and in this case, natural fibers and hollow fibers can be more efficiently bonded. Moreover, the ratio of the content of the non-modified polyolefin resin and the modified resin is preferably 80 to 99% by mass and 1 to 20% by mass, and more preferably 85% when the total of both is 100% by mass. ˜98.5 mass% and 1.5 to 15 mass%, more preferably 90 to 97 mass% and 3 to 10 mass%. In the case of a resin fiber (heat-fusible resin fiber), a resin fiber obtained by spinning a plurality of resins after melt-kneading can be obtained.
In addition, since a plurality of resin fibers (heat-fusible resin fibers) having different structures may be used, for example, a resin fiber made of a non-modified polyolefin resin and a resin fiber made of a modified resin are used in combination. In this case, the proportions of the amounts used are preferably 80 to 99% by mass and 1 to 20% by mass, more preferably 85 to 98.5, respectively, when the total of both is 100% by mass. The mass% is 1.5 to 15 mass%, more preferably 90 to 97 mass% and 3 to 10 mass%.

The shape of the resin fiber (heat-fusible resin fiber) is not particularly limited, but the shape in the length direction can be linear, broken line, curved, spiral, or the like. In addition, the resin fiber (heat-sealable resin fiber) is preferably a solid fiber made of a resin component having a binding action between fibers by melting, but the melting point of the synthetic resin constituting the main body of the hollow fiber or As long as a portion having a melting point lower than the decomposition point is included, a composite fiber such as a core-sheath fiber or a side-by-side fiber may be used.
The length (fiber length) of the resin fiber (heat-fusible resin fiber) is preferably 10 mm or more, more preferably 10 to 150 mm, and still more preferably from the viewpoint of efficient adhesiveness such as natural fibers and hollow fibers. It is 20-100 mm, Most preferably, it is 30-80 mm. The fineness is preferably 1 to 50 dtex, more preferably 2 to 20 dtex, still more preferably 3 to 10 dtex. The outer diameter (fiber diameter) of the resin fiber (heat-fusible resin fiber) is preferably 0.001 to 1.0 mm, more preferably 0.005 to 0.7 mm, and still more preferably 0.007 to 0.5 mm. In a particularly preferred embodiment of the present invention, the resin fiber (heat-sealable resin fiber) having a fiber diameter of 0.001 to 1.0 mm is preferably used with respect to the entire resin fiber (heat-sealable resin fiber). It is used so as to contain 90% by mass or more, more preferably 95% by mass or more.

  The liquid binder composition used in the above methods (A2), (B3), and (C4) can be an aqueous composition, an organic solvent composition, or a liquid composition that does not use a medium. . In the case of an aqueous composition, an adhesive resin (polyolefin resin, acrylic resin, polyacetal resin, polyvinyl alcohol resin, urethane resin or a modified product thereof) or a precursor thereof is used as a medium mainly composed of water. A solution obtained by dissolution, an emulsion obtained by dispersing water in a main medium, or the like can be used. In the case of an organic solvent-based composition, an adhesive resin (polyolefin resin, saturated polyester resin, aromatic vinyl resin, acrylic resin, polyacetal resin or modified products thereof, urethane resin, epoxy resin, etc.) or a precursor thereof A solution obtained by dissolving the body in an organic solvent can be used. Moreover, as a liquid composition which does not use a medium, an acrylic resin, an unsaturated polyester resin, a urethane resin, an epoxy resin, or the like can be used.

As described above, the fiber base material of the present invention can contain other fibers. However, when each of the above methods is applied, the other fibers are solid fibers containing a synthetic resin and inorganic materials. It can be a real fiber or a hollow fiber.
In the above methods (A1), (B1), (B2), (C1), (C2) and (C3), when a solid fiber containing a synthetic resin is used as another fiber, the synthetic resin is a thermoplastic resin. Or it can be set as cured resin. It is essential for this synthetic resin to mainly contain components higher than the melting point and decomposition point of the synthetic resin constituting the hollow fiber, and the remainder can be a resin that can be a binder. Further, in the above methods (A2), (B3) and (C4), in addition to the solid fibers mainly composed of synthetic resins whose melting point and decomposition point are higher than those of the synthetic resins constituting the hollow fibers, Non-limiting solid fibers can also be used.
When other fibers are used as production raw materials, the upper limit of the amount used is usually 40 parts by mass when the amount of the natural fiber used is 100 parts by mass.

Hereinafter, each manufacturing method will be described in detail.
In the above method (A1), it is preferable that the fiber mixture before hot pressing is entangled in advance by needle punching or the like, and has a thickness of about 10 to 50 mm. And after adjusting an entangled thing to predetermined size by using for cutting etc. as needed, a hot press is performed. The heating press heats the entangled material, melts and compresses the resin fibers for the binder (in the case of the method (A1)), bonds at least natural fibers and hollow fibers with the molten resin, and forms a flat pre-board. It is the process of obtaining.
The heating press can be performed by a heating press apparatus using two heat-resistant metal plates, a heating calendar apparatus, or the like. The order of heating and compression is not particularly limited, and these may be performed simultaneously. The temperature at the time of the heating press is a temperature at which the resin fiber (heat-sealable resin fiber) for the binder is melted and the hollow fiber is not melted, preferably the resin fiber (heat-sealable resin fiber). Between a temperature about 40 ° C. higher than the melting temperature of the thermoplastic resin constituting the resin and a temperature about 30 ° C. lower than the melting temperature or decomposition temperature of the hollow fiber.
The pressure at the time of compression is appropriately set depending on the thickness of the entangled material, basis weight, etc., and is not particularly limited, but is preferably 0.8 to 3.2 MPa.

  When the thermoplastic resin constituting the resin fiber for the binder (heat-fusible resin fiber) is a propylene polymer or a modified product thereof, and the hollow fiber is a polyester fiber having pores, the temperature of the heating press is Preferably, they are 170 degreeC-250 degreeC, More preferably, it is 180 degreeC-240 degreeC, More preferably, it is 190 degreeC-230 degreeC.

The pre-board obtained by the heating press is an integrated product in which a melt of resin fibers (heat-fusible resin fibers) serves as a binder, and adjacent fibers of natural fibers and / or hollow fibers are combined, Usually, in the region inside the preboard excluding the joint portion between the fibers, a gap is formed between adjacent fibers. Moreover, the natural fiber and the hollow fiber inside the pre-board may be covered with a melt of resin fiber (heat-fusible resin fiber), or a part of the surface of the fiber may be exposed.
The density of the pre-board is preferably 0.15 to 1.5 g / cm ³ , more preferably 0.2 to 1.0 g / cm ³ .

  In the present invention, the preboard obtained by the above heating press can be used as a fiber substrate as it is, but the preheated flat plate preboard is subjected to a cooling press, and then, if necessary, by cutting or the like. It can also be set as the plate-shaped fiber base material obtained by adjusting to a predetermined size. In addition, the pressure at the time of the cooling press is appropriately set depending on the thickness of the flat preboard, the basis weight, and the like, and is not particularly limited, but is preferably 0.8 to 3.2 MPa.

The said method (A1) can be deform | transformed and the plate-shaped base material containing another fiber can be manufactured. That is, it is a composite fiber such as a natural fiber, a hollow fiber, a core-sheath fiber, a side-by-side fiber, etc., and has a melting point lower than the melting point or decomposition point of the synthetic resin constituting the hollow fiber, and can be a binder. After mixing the part containing the resin (low melting point part) and the composite fiber comprising the part containing the thermoplastic resin having a melting point higher than the melting point or decomposition point of the synthetic resin constituting the hollow fiber (high melting point part) The obtained fiber mixture is heated and pressed at a temperature at which the low melting point portion of the composite fiber melts while the high melting point portion does not melt, and the natural fiber and / or the hollow fiber and / or the high melting point fiber are adjacent to each other. In this method, fibers are bonded together by a melt of a low melting point portion.
The length (fiber length) of the composite fiber is preferably 10 mm or more, more preferably 10 to 150 mm, still more preferably 20 to 100 mm, particularly preferably from the viewpoint of efficient adhesiveness such as natural fibers and hollow fibers. 30 to 80 mm. The outer diameter (fiber diameter) of the composite fiber is preferably 0.001 to 1.0 mm, more preferably 0.005 to 0.7 mm, and still more preferably 0.007 to 0.5 mm. In a particularly preferred embodiment of the present invention, the composite fiber having a fiber diameter of 0.001 to 1.0 mm is preferably contained in an amount of 90% by mass or more, more preferably 95% by mass or more with respect to the entire composite fiber. It is used for.

  In the above method (A2), the fiber mixture before the liquid binder composition is adhered may be entangled in advance. Thereafter, the liquid binder composition is spread to adhere the composition to the fiber surface. The spreading method is not particularly limited, and can be performed by dipping, spraying, padding or the like. And in order to couple | bond together fibers, drying, a heating, etc. are performed according to the kind of composition. Simultaneously or immediately after these operations, pressurization may be performed as necessary. Thereby, the plate-shaped base material with which the adjacent fiber of the natural fiber and / or hollow fiber was couple | bonded by the binder containing a thermoplastic resin or a cured resin can be obtained.

In the method (B1), the method for obtaining the fiber aggregate is not particularly limited. For example, the first fiber raw material mainly composed of resin fibers (heat-fusible resin fibers), natural fibers on the conveyor surface of the belt conveyor The second fiber raw material, mainly natural fibers and hollow fibers, and the third fiber raw material to the third fiber raw material, which are mixed so that the ratio of the natural fiber content and the hollow fiber content gradually decreases. n-1 fiber raw material and n-th fiber raw material (n ≧ 4) mainly comprising hollow fibers are sequentially supplied and deposited; natural fiber, hollow fiber and resin fiber (heat-fusible) Resin fibers) are individually scattered from the storage section that accommodates them to the conveyor surface of the belt conveyor using an air blower or the like, and the specific gravity of each fiber is determined from the conveyor surface side using the difference in specific gravity of each fiber. In ascending order, that is, resin fiber (heat-bondable resin fiber), resin Fiber (heat-sealable resin fiber) and natural fiber, mixed fiber of natural fiber and hollow fiber, and method of depositing in order of hollow fiber; natural fiber, hollow fiber and resin fiber (heat-sealable resin) Fiber mixture) is scattered on the conveyor surface of the belt conveyor using an air blow device or the like, and the difference in specific gravity of each fiber is used to increase the specific gravity from the conveyor surface side, ie, resin fibers ( Examples thereof include a heat-sealable resin fiber), a resin fiber (heat-sealable resin fiber) and a natural fiber mixed fiber, a natural fiber and a hollow fiber mixed fiber, and a hollow fiber in this order.
Said 2nd fiber raw material and 3rd fiber raw material may also contain resin fiber (heat-fusible resin fiber).

Moreover, in the said method (B2), the method of obtaining a fiber accumulation is not specifically limited, For example, on the conveyance surface of a belt conveyor, the 1st fiber raw material mainly having resin fiber (heat-fusible resin fiber), These are made so that the content ratio of the second fiber raw material mainly composed of natural fibers and resin fibers (heat-fusible resin fibers) is constant, and the ratio of the content of natural fibers and the content of hollow fibers gradually decreases. And the third fiber raw material to n-1 fiber raw material mixed with each other, and the n-th fiber raw material (n ≧ 4) mainly composed of hollow fibers are sequentially supplied and deposited.
The second fiber raw material and the n-th fiber raw material may include resin fibers (heat-fusible resin fibers).

  In the above methods (B1) and (B2), it is preferable that the fiber aggregate before hot pressing is entangled in advance, and the thickness is about 10 to 50 mm. Then, after adjusting the entangled material to a predetermined size by subjecting it to cutting or the like, if necessary, it is subjected to a heating press or the like in the same manner as in the above method (A1) to thereby obtain a plate-like fiber base material. Can be obtained. In particular, in the above method (B2), the resin fiber (heat-fusible resin fiber) is melted by heating and pressing with the adhesive resin fiber layer on the upper surface side, and the molten resin is made between the fibers. Flow down the gap and integrate.

  In the method (B3), the method for obtaining the fiber aggregate is not particularly limited. For example, the first fiber raw material mainly composed of natural fibers, the content of the natural fibers, and the hollow fibers on the conveyor surface of the belt conveyor. The second fiber raw material to the n-1th fiber raw material, which are mixed so that the ratio to the content gradually decreases, and the nth fiber raw material (n ≧ 3) mainly including hollow fibers are sequentially supplied. The natural fiber and the hollow fiber are each scattered from the storage unit that accommodates them independently to the conveying surface of the belt conveyor using an air blow device or the like, and the difference in specific gravity of each fiber is utilized. , A method of depositing from the conveying surface side in the order of low specific gravity, that is, natural fibers, mixed fibers of natural fibers and hollow fibers, and hollow fibers in this order; a fiber mixture containing natural fibers and hollow fibers, an air blower, etc. Using Scattered onto the bear's transport surface, using the difference in specific gravity of each fiber, from the transport surface side, in descending order of specific gravity, that is, natural fibers, natural fibers and mixed fibers of hollow fibers, and hollow fibers in order. The method of making it deposit etc. is mentioned.

  In the above method (B3), the fiber aggregate when the liquid binder composition is adhered may be entangled in advance. Thereafter, a plate-like substrate in which natural fibers and hollow fibers are bonded by a binder containing a thermoplastic resin or a cured resin can be obtained by the same operation as in the above method (A2).

Next, in the method (C1), a laminate is obtained by using two fiber aggregates as in the method (B2). It is preferable that the laminate at the time of heat-pressing is entangled, and two entangled materials may be used, or two entangled fiber aggregates are laminated and then entangled. Also good.
The thickness of the laminate is preferably 10 to 400 mm, more preferably 15 to 300 mm, regardless of the presence or absence of entanglement. Then, after adjusting the laminate to a predetermined size by subjecting it to cutting or the like, if necessary, it is subjected to a heating press or the like in the same manner as in the above method (A1) to obtain a plate-like fiber base material. Can be obtained.

In the method (C2), the method for obtaining the first fiber aggregate is not particularly limited, and the method for obtaining the fiber aggregate in the method (B1) can be applied.
Moreover, the method for obtaining the second fiber aggregate is not particularly limited, and the method for obtaining the fiber aggregate in the above method (B3) can be applied.
The laminate composed of the first fiber aggregate and the second fiber aggregate is obtained by stacking the first fiber aggregate and the second fiber aggregate so that the layers having a high content of hollow fibers face each other. Therefore, the composition of the laminate used for the heating press is mainly composed of a layer mainly composed of natural fibers, a layer mainly composed of mixed fibers of natural fibers and hollow fibers, and hollow fibers from the lower side. It consists of a layer, a layer mainly composed of mixed fibers of natural fibers and hollow fibers, a layer mainly composed of natural fibers, and a layer mainly composed of resin fibers (heat-fusible resin fibers).

In the method (C3), the method for obtaining the first fiber aggregate is not particularly limited, and the method for obtaining the fiber aggregate in the method (B1) can be applied.
Also, the method for obtaining the third fiber aggregate is not particularly limited. For example, the first fiber raw material mainly including resin fibers (heat-fusible resin fiber), the second fiber raw material mainly including hollow fibers, natural 3rd fiber raw material-n-1 fiber raw material which mixed mainly so that the ratio of content of a natural fiber and content of a hollow fiber may mainly become large, and a natural fiber, and a natural fiber The n-th fiber raw material (n> = 4) which mainly has this is supplied sequentially, and the method of depositing these etc. is mentioned.
The laminate composed of the first fiber aggregate and the third fiber aggregate is obtained by stacking the first fiber aggregate and the third fiber aggregate so that the layers having a high content of hollow fibers are close to each other. Therefore, the composition of the laminate used for the heating press is mainly composed of a layer mainly composed of natural fibers, a layer mainly composed of mixed fibers of natural fibers and hollow fibers, and hollow fibers from the lower side. A layer mainly composed of resin fibers (heat-fusible resin fibers), a layer mainly composed of hollow fibers, a layer mainly composed of mixed fibers of natural fibers and hollow fibers, and mainly composed of natural fibers. It consists of a layer and a layer mainly composed of resin fibers (heat-fusible resin fibers).

  In the said method (C2) and (C3), it is preferable that the laminated body before performing a hot press is entangled beforehand, and thickness shall be about 10-50 mm. Then, after adjusting the entangled material to a predetermined size by subjecting it to cutting or the like, if necessary, as in the above method (B2), in a state where the adhesive resin fiber layer is the upper surface side, By providing, the resin fiber (heat-fusible resin fiber) is melted, and the molten resin flows down the gap between the fibers, so that an integrated plate-like fiber base material can be obtained.

  In the method (C4), a laminate is obtained by using two same fiber aggregates as in the method (B3). This laminate may or may not be entangled. Thereafter, a plate-like substrate in which natural fibers and hollow fibers are bonded by a binder containing a thermoplastic resin or a cured resin can be obtained by the same operation as in the above method (A2).

  The plate-like substrate made of a flat plate obtained by each of the above methods is further subjected to cold press processing or the like to obtain a fiber substrate made of a curved plate or a fiber substrate having a deep drawn portion. it can.

  The fiber base material of the present invention includes a binding material having the same mass ratio, and is obtained by binding only natural fibers with a binding material when viewed in substantially the same size (length, width and thickness) or basis weight. Compared with the integrated product, the weight can be reduced by 15 to 25%, and the rigidity can be improved by 15 to 30%.

Hereinafter, the production of the fiber base material and the performance thereof will be described specifically by way of examples.
The raw materials used in the following are as follows.
(1) Natural fiber A kenaf fiber having an average fiber length of 70 mm and an average fiber diameter of about 100 μm was used.
(2) Hollow fiber An average fiber length of 51 mm and an outer diameter of about 37 μm, having a shape in which pores with an inner diameter of about 16 μm penetrate from one end side to the other end side, the porosity is 20% by volume, A fiber containing a polyethylene terephthalate resin having a melting point of about 264 ° C. was used.
(3) Heat-fusible resin fiber 5% by mass of acid-modified polypropylene “Yumex 1001” manufactured by Sanyo Kasei Kogyo Co., Ltd. (Trade name) and 95% by mass of a mixture of ethylene polypropylene block copolymer resin “Novatech SA01” (trade name) manufactured by Nippon Polypro Co., Ltd., obtained by melt spinning, fineness 6.6 dtex, average fiber length 51 mm In addition, resin fibers having an average fiber diameter of 29 μm were used. The melting point of the heat-fusible resin fiber is 150 ° C. to 180 ° C.

Example 1
After mixing 60% by mass of natural fiber, 10% by mass of hollow fiber, and 30% by mass of heat-fusible resin fiber to obtain a fiber mixture (A), the fiber mixture (A) is carded. The apparatus was put into the apparatus to produce a web having a thickness of about 200 mm. And the entanglement by needle punching was performed and the mat about 20 mm thick was obtained.
Next, this mat was compressed at a pressure of 32 kgf / cm ² using a press machine in which the mold temperature was set to 235 ° C. until the internal temperature of the mat during compression became 180 ° C. or higher, and the thickness was 2.5 mm. A plate-like fiber substrate was obtained (see FIG. 1). By this method, five samples having a basis weight of 0.674 g / m ² , 0.692 g / m ² , 0.712 g / m ² , 0.731 g / m ² and 0.740 g / m ² were obtained.

  The rigidity of the obtained plate-like fiber substrate was evaluated by a bending elastic gradient. This bending elastic gradient supports a test piece having a size of 50 mm × 150 mm at two fulcrums (curvature radius of 3.2 mm) set at an interval of 100 mm in the measurement of the maximum bending load according to JIS K 7171. This is a load obtained by deforming 10 mm from the initial linear portion of the load / deflection curve obtained by applying a load at a speed of 50 mm / min from an action point (curvature radius of 3.2 mm) arranged at the center between the fulcrums. The bending elastic gradient of each sample is shown in FIG.

Example 2
A plate-like fiber substrate was obtained in the same manner as in Example 1 except that the thickness was 3.0 mm. The basis weight of ^{0.672g / m 2, 0.689g / m} 2, 0.697g / m 2, about 5 sample of 0.712 g / ^{m 2} and 0.735 g / ^{m 2,} to obtain a bending elasticity gradient. The result is shown in FIG.

Comparative Example 1
Example 1 except that instead of the fiber mixture (A), a fiber mixture (B) obtained by mixing 60% by mass of natural fiber and 40% by mass of heat-fusible resin fiber was used. Similarly, a plate-like fiber substrate having a thickness of 2.5 mm was obtained. The basis weight of ^{0.674g / m 2, 0.692g / m} 2, 0.712g / m 2, about 5 sample of 0.731 g / ^{m 2} and 0.740 g / ^{m 2,} to obtain a bending elasticity gradient. The result is shown in FIG.

As is clear from FIG. 5, in the fiber base material having a basis weight in the range of 0.60 to 0.80 kg / m ² , Examples 1 and 2 have a higher bending elastic gradient than Comparative Example 1 and are excellent in rigidity. I understand that.

  The foregoing examples are for illustrative purposes only and are not to be construed as limiting the invention. Although the invention has been described with reference to exemplary embodiments, it is understood that the language used in the description and illustration of the invention is illustrative and exemplary rather than limiting . As detailed herein, changes may be made in its form within the scope of the appended claims without departing from the scope or spirit of the invention. Although specific structures, materials and examples have been referred to in the detailed description of the invention herein, it is not intended to limit the invention to the disclosure herein, but rather, the invention is claimed. It covers all functionally equivalent structures, methods and uses within the scope of

The fiber base material of the present invention is suitable in the fields of vehicles, ships, aircraft, houses, daily necessities, and the like that require rigidity, strength, soundproofing, heat insulation and the like. Since the fiber base material of the present invention has high rigidity as compared with a base material obtained by using only plant fibers and bonded with a thermoplastic resin, the base material used for the interior material or the exterior material in the above field, It is suitable as a structural material. Hereinafter, application products using the fiber base material of the present invention will be exemplified. Some of these applied products have a surface layer.
In the vehicle field, for automobiles, door base materials, package trays, pillar garnishes, switch bases, quarter panels, armrest core materials, door trims, seat backboards and other seat structure materials, console boxes, dashboards, instrument panels, Deck trim, bumper, spoiler, cowling, etc.
In the marine field and the aircraft field, package trays, armrest cores, seat structure materials such as seat backboards, console boxes, dashboards, instrument panels, and the like.
Further, in the housing field, for furniture, cover materials or structural materials such as desks, chairs, shelves, and bags, cover materials or structural materials for doors, walls, or structural materials thereof may be used.
In addition, the present invention can also be applied to a package, a container, a protective member, a partition member, a shoe core, or an insole.

10: Fiber substrate, 11: Natural fiber, 13: Hollow fiber, 15: Binder, 16: Resin layer, 17: Natural fiber layer, 18: Hollow fiber layer, 21: Hollow fiber layer (central region), 23: Natural fiber layer, 24: natural fiber layer (intermediate region), 26: resin layer (surface region)

Claims (6)

  A fiber base material containing a natural fiber and a resin serving as a binder, and containing a hollow fiber containing a synthetic resin.   The fiber substrate according to claim 1, wherein the fiber substrate is plate-shaped, and the content ratios of the resin, the natural fiber, and the hollow fiber are gradually changed in the thickness direction.   The fiber base material is plate-shaped, and is located on a central region mainly composed of the hollow fibers, an intermediate region mainly composed of the natural fibers located on both sides of the central region, and an outer surface of the intermediate region. And a surface region mainly composed of the resin, wherein the hollow fiber, the natural fiber, and the resin content ratio gradually change in the thickness direction from the central region toward the surface region. Item 2. A fiber substrate according to Item 1.   When the said fiber base material is 100 mass%, content of the said natural fiber is 40-60 mass%, content of the said resin is 25-55 mass%, and content of the said hollow fiber is 5 The fiber base material according to any one of claims 1 to 3, which is -15 mass%.   The fiber substrate according to any one of claims 1 to 4, wherein the resin includes a thermoplastic resin. Fiber base material according to any one of claims 1 to 5 weight per unit area is 0.5~1.0kg / ^{m 2.}

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