JP2021098297A - Method for manufacturing fiber board and fogging reduction method of vehicle interior material - Google Patents

Abstract

To provide a method for manufacturing a fiber board, and a fogging reduction method of a vehicle interior material using the fiber board which can suppress fogging.SOLUTION: A manufacture method includes the steps of: forming a fiber mat 10 containing vegetable fibers 10a and resin fibers 10b; heating and pressing the fiber mat 10 to obtain a fiber board; and reducing moisture contained in the fiber mat 10 and/or the fiber board. A reduction method is a fogging reduction method of a vehicle interior material having a substrate layer obtained by bonding vegetable fibers by a binder resin and includes a step of reducing moisture contained in the substrate layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a fiber board and a method for reducing fogging of vehicle interior materials. More specifically, the present invention relates to a method for producing a fiber board using plant fiber as a reinforcing fiber, and a method for reducing fogging of a vehicle interior material using such a fiber board as a base material layer.

In recent years, a fiber board having a structure in which plant fibers are bound to each other with a binding resin has been known as a lightweight base material while having high rigidity. And such a fiber board is used as a vehicle interior material. Further, conventionally, while various characteristics are required for vehicle interior materials, there is a demand for fogging characteristics. That is, in a vehicle that becomes hot, various components may be volatilized, and the volatilized components may be subsequently cooled to fog the inner surface of the window glass. Such a phenomenon is called fogging, and it is generally required to suppress fogging.
The following Patent Document 1 refers to fogging in a fiber board using plant fibers as described above.

Japanese Unexamined Patent Publication No. 2014-233769

As described above, when the presence or absence of fogging and the degree of fogging were measured for a fiber board having a structure in which plant fibers were bound to each other with a binding resin, it was found that fogging may occur at a level requiring improvement. In such cases, conventionally, it has been dealt with by identifying the volatile component that causes the problem and considering a method of not using the volatile component, or by substituting with another component of the volatile component. It was. In this respect, the same applies to Patent Document 1. That is, when the base material layer 3 and the skin layer 5 are bonded together, fogging is prevented by not using an adhesive containing a volatile component.

However, in this case, it was found that it was difficult to identify the volatile components. That is, the fiber board as described above is obtained by heating and compressing a fiber mat obtained by mixing plant fibers and resin fibers serving as a binder resin, and each of the plant fibers and the resin fibers is used. Almost no fogging was observed even when subjected to the fogging test. That is, the result was obtained that the raw material of the fiber board did not contain the causative substance that causes fogging, while the result was that fogging was observed in the fiber board using these raw materials.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a fiber board capable of suppressing fogging. Another object of the present invention is to provide a method for reducing fogging of vehicle interior materials using a fiber board.

That is, the present invention is as shown below.
[1] The method for producing a fiber board of the present invention includes a mat forming step of forming a fiber mat containing plant fibers and resin fibers, and a mat forming step.
A board forming step of heating and pressurizing the fiber mat to obtain a fiber board,
It is characterized by comprising a reduction step of reducing the water content contained in the fiber mat and / or the fiber board.
[2] In the method for producing a fiber board of the present invention, the reduction step can be a step of reducing water content by heating.
[3] In the method for producing a fiber board of the present invention, the reduction step can be a step of reducing the water content of the fiber mat or the fiber board to less than 3%.
[4] The method for reducing fogging of a vehicle interior material of the present invention is a method for reducing fogging of a vehicle interior material having a base material layer in which plant fibers are bound to each other by a binder resin.
It is characterized by comprising a reduction step of reducing the water content contained in the base material layer.
[5] In the method for reducing fogging of vehicle interior materials of the present invention, the reduction step can be a step of reducing moisture by heating.
[6] In the method for reducing fogging of vehicle interior materials of the present invention, the reduction step can be a step of reducing the water content of the base material layer to less than 3%.

According to the method for producing a fiber board of the present invention, fogging can be suppressed. According to the method for reducing fogging of a vehicle interior material of the present invention, it is possible to suppress fogging of a vehicle interior material provided with a fiber board having a structure in which plant fibers are bound to each other with a binding resin as a base material layer.

It is explanatory drawing explaining the fiber mat. It is explanatory drawing explaining the fiber board. It is explanatory drawing explaining the vehicle interior material. It is explanatory drawing explaining the reduction process with respect to the fiber mat. It is explanatory drawing explaining the reduction process with respect to a fiber board. It is explanatory drawing explaining the reduction process with respect to the vehicle interior material. It is explanatory drawing explaining the manufacturing process of a fiber board. It is explanatory drawing explaining the manufacturing process of the vehicle interior material. It is explanatory drawing explaining the evaluation method of the fogging characteristic.

Hereinafter, the present invention will be described with reference to the drawings. The matters shown here are for exemplifying and exemplifying embodiments of the present invention, and are considered to be the most effective and effortless explanations for understanding the principles and conceptual features of the present invention. It is stated for the purpose of providing what is to be done. In this regard, it is necessary for a fundamental understanding of the present invention and is not intended to provide structural details of the present invention beyond a certain degree, and some embodiments of the present invention will be provided by description in conjunction with the drawings. It reveals to those skilled in the art how is actually embodied.

[1] Method for Manufacturing Fiber Board The method for manufacturing a fiber board of the present invention is characterized by having a mat forming step (R1), a board forming step (R2), and a reducing step (R3) (FIGS. 1 to 1). 2. See FIGS. 4-5 and 7).

As described above, this method includes a reduction step R3 for reducing the water content contained in the fiber mat and / or the fiber board. By providing this reduction step R3, it is considered that fogging can be suppressed extremely effectively in the present invention. The mechanism is not clear, but it is considered that the fogging-causing component existing or existing on the surface of the resin fiber constituting the fiber mat 10 can be volatilized together with water.
More specifically, in various devices that allow the resin fibers to pass through until the resin fibers reach the fiber mat, a surface active component may be imparted to the surface of the resin fibers for the purpose of improving the slipperiness. .. It is considered that this surfactant component alone does not cause fogging. However, when water is present, it is considered that it is dissolved in the water, volatilized together with the water, and precipitated by being cooled. Then, it is considered that the water brought in by the plant fiber is used as the water at this time. Therefore, it is considered that the fogging-causing component can be removed at the same time by removing the water to the outside of the system when the component to be removed is sufficiently dissolved in the water.

The above-mentioned "mat forming step (R1)" is a step of forming a fiber mat 10 containing plant fibers 10a and resin fibers 10b.

The fiber mat 10 may be formed in any way. Specifically, it can be formed by using a web making device such as an air array or a card. For example, when an air array is used, the fibers are blown off by blowing air so that the plant fibers 10a and the resin fibers 10b are mixed in a desired ratio, and the fibers are deposited to a desired thickness to obtain a web (coarse web 11A and a coarse web 11A and a web). 11B) can be obtained. The webs (11A and 11B) may be used as the fiber mat 10 as they are, but the laminated web (11C) obtained by stacking a plurality of webs can be used as the fiber mat 10. Further, when the laminated web (11C) is used, the laminated web (11C) can be needle punched (a needle punching machine 5 can be used) to strengthen the entanglement. Further, the obtained laminated web (11C) can be cut into a desired size and shape using a cutting machine 6 to obtain a fiber mat 10 (see FIG. 7).

The basis weight and thickness of the fiber mat 10 are not limited, but for example, the basis weight can be 400 to 3000 g / m ^2, and further can be 600 to 2000 g / m ² . Further, the thickness can be 5 mm or more (usually 50 mm or less), and further can be 8 to 40 mm, particularly 10 to 30 mm.

The ratio of the plant fiber 10a and the resin fiber 10b in the fiber mat 10 is not limited, but when the total of the plant fiber 10a and the resin fiber 10b is 100% by mass, the plant fiber 10a is 30 to 95% by mass. Preferably, 32 to 85% by mass is more preferable, 33 to 75% by mass is further preferable, and 35 to 70% by mass is particularly preferable. Further, when the total amount of the fiber mat 10 is 100% by mass, the total amount of the plant fiber 10a and the resin fiber 10b is preferably 70% by mass or more, more preferably 80 to 100% by mass, and 85 to 100% by mass. Is more preferable, and 90 to 100% by mass is particularly preferable.

The plant fiber 10a is a fiber derived from a plant. The part of the plant body containing the plant fiber is not limited, and may be any part such as a woody part, a non-woody part, a leaf part, a stem part and a root part. Further, only a specific part may be used, or two or more different parts may be used in combination.
The fiber taken out from the plant may be used as it is as a plant fiber, or may be processed into various processes and then used as a plant fiber. Examples of various processes include letting (including letting using microorganisms, letting using enzymes, etc.), boiling, steaming, heating, drying, cutting, tapping, washing, chemical treatment, and the like. Only one of these may be used, or two or more thereof may be used in combination.

The plant species from which plant fibers are extracted are not limited, but for example, kenaf, jute hemp, Manila hemp, sisal hemp, ganpi, mitsumata, mulberry, banana, pineapple, coconut palm, corn, sugar cane, bagasse, palm, papyrus, reed, esparto, survivorgrass. , Wheat, rice, bamboo, conifers (sugi, cypress, etc.), broadleaf trees, cotton, etc. Only one of these may be used, or two or more thereof may be used in combination. Of these, kenaf and / or jute hemp is preferred.
Kenaf is a plant that has a woody stem and is classified in the Malvaceae family. This kenaf includes hibiscus cannabinus and hibiscus sabdarifa in the scientific name, and includes red hemp, cuba kenaf, western hemp, taikenaf, mesta, bimuri, ambari hemp, bombay hemp and the like in the common names.
In addition, jute hemp includes plants of the family Tiliaceae and hemp, including corchorus capsularis (Corchorus capsularis L.), and nalta jute, Nalta jute and Moroheiya.

The fiber length and diameter of plant fibers are not limited. From the viewpoint of the mechanical properties required for the obtained fiber mat, the fiber board obtained by using the fiber mat, and the vehicle interior material obtained by using the fiber board, the ratio of the fiber length to the fiber diameter is 10 to 10. 15000 is preferable. Further, the fiber length is preferably 10 mm or more. As a result, high strength (flexural strength, flexural modulus, etc., the same applies hereinafter) can be obtained. The fiber length is more preferably 10 to 150 mm, further preferably 20 to 100 mm, and particularly preferably 30 to 80 mm.
The fiber diameter is preferably 1 mm or less, more preferably 0.01 to 1 mm, further preferably 0.02 to 0.7 mm, and particularly preferably 0.03 to 0.5 mm. In this range, high strength can be obtained in the obtained fiber board and the vehicle interior material using the fiber board. The plant fiber may contain a fiber that deviates from the fiber length and the fiber diameter, but the content thereof is preferably 10% by mass (particularly 3% by volume) or less with respect to the total plant fiber.

The fiber length means the average fiber length (the same applies hereinafter), and in accordance with JIS L1015, single fibers are randomly taken out one by one by a direct method, and the fiber lengths are measured on a scale and totaled. It is an average value measured for 200 fibers. Further, the fiber diameter means an average fiber diameter (the same applies hereinafter), and single fibers are randomly taken out one by one, and the fiber diameter at the center in the length direction of the fibers is measured using an optical microscope, and a total of 200 fibers are measured. It is an average value measured for a book.

On the other hand, the resin fiber 10b is a resin molded into a fibrous form. The resin type constituting the resin fiber 10b is not limited, but a polyrefin resin is preferable from various viewpoints such as mechanical properties, distribution amount, cost, and the like. Examples of the olefin monomer constituting the polyolefin resin include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene and 1-. Examples include hexene and 1-octene. Only one of these may be used, or two or more thereof may be used in combination.

Therefore, examples of the polyolefin resin include polypropylene resins such as a propylene homopolymer, a propylene / ethylene copolymer, and a propylene / 1-butene copolymer. These polypropylene resins are resin in which 50% or more of the total number of constituent units is derived from propylene. Further, polyethylene resins such as an ethylene homopolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and an ethylene / 4-methyl-1-pentene copolymer can be mentioned. These polyethylene resins are resin in which 50% or more of the total number of constituent units is derived from ethylene.
The molecular weight of the polyolefin resin is not limited, but for example, the weight average molecular weight (according to the GPC method) is preferably 1000 to 20000, more preferably 1500 to 100,000, further preferably 20000 to 60000, and particularly preferably 2500 to 45000.

Further, the above-mentioned polyolefin resin constituting the resin fiber 10b may consist only of a non-modified polyolefin resin, but may include an acid-modified polyolefin resin. When the acid-modified polyolefin resin is contained, the binding property between the melted resin fiber 10b and the plant fiber 10a can be improved, and the mechanical properties of the obtained fiber board 20 can be improved.
The acid-modified polyolefin resin is a resin in which an acid-modified group is introduced into a polyolefin resin which is a skeleton resin. Examples of the acid-modifying group include an anhydrous carboxylic acid group (-CO-O-OC-) and a carboxylic acid group (-COOH). Only one of these may be used, or two or more thereof may be used in combination.
Further, the acid-modifying group may be introduced using any compound, for example, maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, maleic acid, itaconic acid, fumaric acid. It can be introduced using an acid, acrylic acid, methacrylic acid or the like. Only one of these may be used, or two or more thereof may be used in combination. Among these, maleic anhydride and itaconic anhydride are preferable, and maleic anhydride is particularly preferable.

The molecular weight of the acid-modified polyolefin resin is not limited, but for example, the weight average molecular weight (according to the GPC method) is preferably 1000 to 20000, more preferably 1500 to 100,000, further preferably 2000 to 60000, and particularly preferably 2500 to 45000. The acid value (according to JIS K0070) is preferably 15 or more (usually 80 or less), more preferably 15 to 70, further preferably 20 to 60, and particularly preferably 23 to 30. Among these, in the present invention, maleic anhydride-modified polypropylene having a weight average molecular weight of 2500 to 45000 and an acid value of 20 to 60 is preferable.

When the resin fiber 10b contains an acid-modified polyolefin resin, the ratio of the non-modified polyolefin resin to the acid-modified polyolefin resin is not limited, but when the total of these is 100% by mass, the ratio of the acid-modified polyolefin resin is 50. It is preferably 0% by mass or less (usually 0.1% by mass or more), more preferably 0.5 to 40% by mass, further preferably 1 to 30% by mass, particularly preferably 2 to 20% by mass, and 3 to 20% by mass. 10% by mass is particularly preferable.

The fiber length and fiber diameter of the resin fiber 10b are not limited, but the ratio of the fiber length to the fiber diameter is preferably in the range of 10 to 15000. More specifically, the fiber length is preferably 10 mm or more, more preferably 10 to 150 mm, further preferably 20 to 100 mm, and particularly preferably 30 to 80 mm.
The fiber diameter is preferably 1 mm or less, more preferably 0.001 to 1.5 mm, further preferably 0.005 to 0.7 mm, further preferably 0.008 to 0.5 mm, and 0.01 to 0.3 mm. Is particularly preferable.
The resin fiber 10b may include a resin fiber having a form outside the above-mentioned fiber length and fiber diameter. When the resin fiber 10b in the out-of-form form is contained, the content thereof is preferably 10% by mass (particularly 3% by volume) or less with respect to the entire resin fiber 10b. The method for measuring the fiber length and the fiber diameter is the same as that for the plant fiber 10a.

The fineness of the resin fiber 10b is not limited, but is preferably 15 dtex or less, for example. By suppressing the fineness of the resin fiber 10b to 15 dtex or less, a form that is more easily used as a fiber mat raw material can be obtained. That is, it is possible to make it easier to mix the fiber with the plant fiber 10a. The fineness is further preferably 1 to 15 dtex, more preferably 3 to 11 dtex, and even more preferably 4 to 10 dtex.

The resin fiber 10b may be composed of only a polyolefin resin (non-modified polyolefin resin, acid-modified polyolefin resin), but may contain other thermoplastic resins. When another thermoplastic resin is contained, the amount of the other thermoplastic resin is preferably 30% by mass or less, preferably 15% by mass, when the total amount of the thermoplastic resin constituting the resin fiber 10b is 100% by mass. The following is more preferable, and 5% by mass or less is particularly preferable.

Other thermoplastic resins include modified polyolefins having no acid-modifying groups (polyamides modified by groups other than acid-modifying groups), polyester resins (aliphatic polyester resins, aromatic polyester resins), and aromatic vinyl resins. (Polyester resin), acrylic resin, polyamide resin (aliphatic polyamide resin, aromatic polyamide resin), polycarbonate resin, polyacetal resin, ABS resin and the like can be mentioned. Only one of these may be used, or two or more thereof may be used in combination.
Further, the resin fiber 10b may contain, for example, a bulking agent, a coloring agent, an inorganic flame retardant, or the like, in addition to the resin, if necessary.

In addition to the plant fiber 10a and the resin fiber 10b, the fiber mat 10 can include, for example, a heat-expanding capsule and other reinforcing fibers other than the plant fiber 10a. Examples of other reinforcing fibers include metal fibers, carbon fibers, glass fibers, resin fibers (resin fibers excluding the above-mentioned resin fibers 10b, for example, polyamide resin fibers, polyester resin fibers, etc.) and the like. Only one of these may be used, or two or more thereof may be used in combination.
When other reinforcing fibers are included, when the total of the plant fiber 10a, the other reinforcing fibers and the resin fiber 10b is 100% by mass, the ratio of the other reinforcing fibers is usually 50% by mass or less, which is 20% by mass. % Or less is preferable, 10% by mass or less is more preferable, and 5% by mass or less is particularly preferable. The lower limit is not limited, but can be, for example, 0.1% by mass or more.

The above-mentioned "board forming step (R2)" is a step of heating and pressurizing a fiber mat to obtain a fiber board (see FIGS. 2 and 7).

In the board forming step R2, by heating and pressurizing the fiber mat 10, the resin fibers 10b are melted by heating to become a molten thermoplastic resin. Since the molten thermoplastic resin is pressurized, it also flows between the plant fibers 10a. Then, by stopping the heating, the molten thermoplastic resin is solidified, and the fiber mat 10 becomes the fiber board 20. Therefore, the fiber board 20 is formed into a plate shape by binding the plant fibers 20a to each other by the binding resin 20b.

The plant fiber 20a in the fiber board 20 is substantially the same as the plant fiber 10a in the fiber mat 10, but is it heated and pressurized when the fiber mat 10 is processed into the fiber board 20? It differs in whether or not. The binding resin 20b in the fiber board 20 is a resin obtained by solidifying the resin fibers 10b in the fiber mat 10 after being melted, and is a resin that binds the plant fibers 10a to each other. As for the details of the binder resin 20b, the description given in the resin fiber 10b can be applied except that it does not have a fiber shape.

The heating temperature in the board forming step R2 is not limited, and may be any temperature as long as the resin fibers 10b can be melted. Specifically, it is usually 150 to 280 ° C. In particular, when the resin fiber 10b is made of a non-modified polypropylene resin (which may further contain an acid-modified polypropylene resin), the heating temperature is preferably 170 to 250 ° C. It is more preferably 180 to 240 ° C., and particularly preferably 190 to 230 ° C. Further, when the molten thermoplastic resin is solidified, it is preferable to cool it to about 20 to 30 ° C. This cooling may be forced cooling or may be allowed to cool.

The pressurization in the board forming step R2 can be performed at the same time as or separately from the heating. By applying pressure, plant fibers can be bound more firmly. In addition, the thickness of the obtained fiber board 20 can be controlled. The pressure at this time is not particularly limited and can be changed according to desired characteristics, but for example, it can be 0.5 to 8 MPa, preferably 0.7 to 5 MPa, and more preferably 1 to 4 MPa.
As described above, heating and pressurization may be performed at the same time, or heating and pressurization may be performed separately. If done separately, the pressurization is usually performed before the molten thermoplastic resin is solidified. On the other hand, as a form of simultaneous operation, a hot press (hot press machine 7, see FIG. 7) can be used. By using the hot press, the plant fibers 20a (10a) can be restrained by the binding resin 20b in a compressed state, so that the thickness of the obtained fiber board 20 can be made smaller. be able to.

The basis weight and thickness of the fiber board 20 are not limited, but for example, the basis weight can be 400 to 3000 g / m ^2, and further can be 600 to 2000 g / m ² . Further, the thickness can be 0.5 mm or more (usually 50 mm or less), and further can be 1 to 25 mm, particularly 1.5 to 10 mm.

The above-mentioned "reduction step (R3)" is a step of reducing the water content contained in the fiber mat and / or the fiber board (see FIGS. 4 to 5).
That is, the reduction step R3 may be performed after the mat forming step R1, may be performed after the board forming step R2, or may be performed after both of these steps. Of these, it is preferable to perform the reduction step R3 after at least the board forming step R2. Further, the reduction step R3 may be performed only once, or may be performed a plurality of times of two or more times.

Moreover, the method for reducing the water content (moisture content) is not limited. For example, the water content may be reduced by placing it in a reduced pressure environment, or the water content may be reduced by placing it in a warming environment. Furthermore, the water content can be reduced by freeze-drying. Only one of these methods may be used, or two or more of these methods may be used in combination.

Among these, the reduction step R3 is preferably a step of reducing the water content by at least heating. By reducing the water content by heating, the efficiency of removing the fogging-causing component can be particularly improved. The reason for this is not clear, but by heating, the fogging-causing component (fatty acid ester, etc.) can be more efficiently dissolved in water, and by volatilizing the water containing more of the dissolved fogging-causing component, the water can be volatilized. It can be considered that the fogging-causing component can be more effectively removed from the system.

When the reduction step R3 is performed by heating, the temperature is not limited, but is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, further preferably 70 ° C. or higher, and particularly preferably 75 ° C. or higher. On the other hand, the upper limit of the temperature at the time of heating is not limited, but for example, 150 ° C. or lower is preferable, 120 ° C. or lower is more preferable, 100 ° C. or lower is further preferable, and 90 ° C. or lower is particularly preferable.
Further, the heating is preferably heating in a state where no pressure is applied, rather than heating in a pressurized environment such as a hot press. That is, for example, heating in an open system, heating in a constant temperature bath, or heating in a reduced pressure environment is preferable.

Further, in the reduction step R3, the water content may be reduced to any extent, and for example, the water content of the fiber mat and / or the fiber board to be water-reduced can be reduced to 5% or less. Further, the step is preferably a step of reducing to 4% or less, and further preferably a step of reducing to less than 3%. In the reduction step R3, when the water content is reduced to less than 3%, fogging can be suppressed particularly effectively.
It is not a problem that the water content intentionally or unavoidably increases after the reduction step R3 is performed. As described above, it is considered that the fogging-causing component is removed from the system as the water content decreases, so even if the water content increases thereafter, the fogging-causing component contained in the fiber mat or the fiber board is reduced. This is because it is possible to maintain the state of being used.

[2] Method for reducing fogging of vehicle interior material In the method for reducing fogging of vehicle interior material of the present invention, fogging of vehicle interior material 30 having a base material layer 31 formed by binding plant fibers 31a to each other by a binder resin 31b is performed. It is a method of reducing.
The method is characterized by including a reduction step R3 for reducing the water content contained in the base material layer 31 (see FIGS. 3 and 6).

The base material layer 31 is a layer forming a base material of the vehicle interior material 30. As the base material layer 31, the above-mentioned fiber board 20 and its processed product can be used. As for the matters relating to the fiber board 20, the above description can be applied as it is. Further, examples of the processed product of the fiber board 20 include those obtained by applying heating, pressurization and / or shaping to the fiber board 20. More specifically, as the vehicle interior material 30 according to the present invention, the fiber board 20 in which the binder resin 20b is softened or melted by heating (heating device 8) and the skin layer 32 are overlapped and cooled. Examples include those pressed (cold press machine 9) (that is, via a molding step R4 including a heating step R41 and a shaping step R42). As a result, the fiber board 20 (base material layer 31) and the skin layer 32 are bonded together to form a vehicle interior material 30 shaped as necessary (see FIG. 8).

As described above, the vehicle interior material 30 may include other layers, other parts, and the like in addition to the base material layer 31. For example, the epidermis layer 32 can be mentioned. Examples of the skin layer 32 include woven fabrics, knitted fabrics, non-woven fabrics, natural leathers, synthetic leathers, resin sheets, coating layers and the like. Only one of these may be used, or two or more thereof may be used in combination. Further, examples of the other layer include an adhesive layer and the like.

The specific type of vehicle interior material 30 is not limited, but for example, instrument panel, door trim, package tray, pillar garnish, switch base, quarter panel, armrest, seat, seat backboard, ceiling material, console box, dashboard. , Deck trim, etc. Only one of these may be used, or two or more thereof may be used in combination.

In this method, the reduction step R3 may be performed only on the base material layer 31, may be performed on the vehicle interior material 30, or may be performed on an intermediate object in the process of becoming the vehicle interior material 30. You may. The case where the reduction step R3 is performed only on the base material layer 31 is the case where the reduction step R3 is performed only on the base material layer 31 before adding another configuration in the process of obtaining the vehicle interior material 30. Can be mentioned. Further, the case where the reduction step R3 is performed on the vehicle interior material 30 includes the case where the reduction step R3 is performed on the entire obtained vehicle interior material 30 (that is, for example, the base material layer 31 and the skin). When the reduction step R3 is performed on the entire layer 32 in a bonded state). Further, the case where the reduction step R3 is performed on an intermediate object in the process of becoming the vehicle interior material 30 is a state in which another configuration is added to the fiber board 20 before the vehicle interior material 30 is obtained. , There is a case where the reduction step R3 is performed on the intermediate product.
Further, the reduction step R3 may be performed only once, or may be performed a plurality of times of two or more times.

Moreover, the method for reducing the water content (moisture content) is not limited. For example, the water content may be reduced by placing it in a reduced pressure environment, or the water content may be reduced by placing it in a warming environment. Furthermore, the water content can be reduced by freeze-drying. Only one of these methods may be used, or two or more of these methods may be used in combination.

Among these, the reduction step R3 is preferably a step of reducing the water content by at least heating. By reducing the water content by heating, the efficiency of removing the fogging-causing component can be particularly improved. The reason for this is not clear, but heating can more efficiently dissolve the fogging-causing component in water, and by volatilizing the water containing more of the dissolved fogging-causing component, the fogging-causing component can be more efficiently dissolved. It can be considered that it can be effectively removed from the system.

When the reduction step R3 is performed by heating, the temperature is not limited, but is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, further preferably 70 ° C. or higher, and particularly preferably 75 ° C. or higher. On the other hand, the upper limit of the temperature at the time of heating is not limited, but for example, 150 ° C. or lower is preferable, 120 ° C. or lower is more preferable, 100 ° C. or lower is further preferable, and 90 ° C. or lower is particularly preferable.
Further, the heating is preferably heating in a state where no pressure is applied, rather than heating in a pressurized environment such as a hot press. That is, for example, heating in an open system, heating in a constant temperature bath, or heating in a reduced pressure environment is preferable.

Further, in the reduction step R3, the water content may be reduced to any extent, and for example, the water content of the base material layer 31 to be reduced in water content can be reduced to 5% or less. The step is preferably a step of reducing to less than 3%, and more preferably a step of reducing to less than 3%. In the reduction step R3, when the water content is reduced to less than 3%, fogging can be suppressed particularly effectively.
It is not a problem that the water content intentionally or unavoidably increases after the reduction step R3 is performed. As described above, it is considered that the fogging-causing component is removed from the system as the water content is reduced, so that even if the water content is subsequently increased, the fogging-causing component contained in the base material layer 31 is reduced. This is because it is possible to maintain the state.

Hereinafter, the present invention will be specifically described with reference to Examples.
[1] Preparation of fiber board Kenaf fibers (average fiber length 70 mm, fineness 4 to 10 dtex) were prepared as plant fibers. Kenaf fiber is a plant fiber obtained by defibrating the bast taken out from kenaf by a letting treatment.
As the resin fiber, a fiber (average fiber length 50 mm) made of a non-modified polyolefin resin (homopolypropylene resin, melting point 165 ° C.) was prepared.
The kenaf fibers and the resin fibers were laminated using a card machine to obtain a fiber web (fiber aggregate) in which the mass ratio of the kenaf fibers to the resin fibers was 60:40.
The obtained fiber web was heated to 200 ° C. and then cooled to 25 ° C. (cooling press) while pressing to obtain a fiber board (molded product) having ^{a thickness of 2.4 mm and a basis weight of 1.0 kg / m 2.} ..

[2] Evaluation of Fogging Characteristics The kenaf fiber and resin fiber used in the above [1], and the fiber board obtained in the above [1] are measured for the fogging characteristics in accordance with ISO6452, and the glossiness is measured. Was evaluated using. The details are shown below.

(1) Measurement of pre-moisture content The moisture content of kenaf fiber, resin fiber, and fiber board was measured using a heat-drying moisture meter (manufactured by AND, model "MX-50"). As a result, the water content of each measurement target was as follows.
Experimental Example 1: Kenaf fiber 11.9%
Experimental example 2: Resin fiber 0.69%
Experimental example 3: Fiber board 5.67%

(2) Reduction of water content (reduction step R3)
The fiber board was placed in a constant temperature bath at a temperature of 80 ° C., and the water content after 24 hours was measured.
Experimental Example 4: Fiber board 1.16%

(3) Specific Evaluation of Fogging Using the device shown in FIG. 9, the tall beaker 42 containing the measurement sample 41 was submerged in an oil bath 43 at a temperature of 100 ° C., and the opening of the tall beaker 42 was closed with a glass plate 44. While cooling the glass plate 44, remove the glass plate 44 after 180 minutes, and after 4 hours, the glossiness of the surface of each glass plate 44 (glossiness meter: manufactured by Suga Test Instruments Co., Ltd., model "UGV-5DP"") Was measured. Then, the glossiness when the kenaf fiber of Experimental Example 1 was used was set to 1.00, and the glossiness of each measurement target of Experimental Examples 2 to 4 was expressed as a ratio (glossiness ratio). The results are shown in Table 1.

(4) Effect of Example As described above, the glossiness ratio shown in Table 1 is a relative ratio of the glossiness of other measurement targets when the glossiness of the kenaf fiber is 1.00. The glossiness, which is a measured value, is a value indicating that the larger the value (maximum value 100%), the less fogging. Further, among Experimental Examples 1 to 4, the glossiness was the largest value in Experimental Example 1, and no fogging was substantially caused. Therefore, the larger the glossiness ratio (maximum value 1.00), the less fogging is.
As a result of the test, the glossiness ratio of Experimental Example 1 using only kenaf fibers was 1.00, and the glossiness ratio of Experimental Example 2 using only resin fibers was 0.96. However, there is virtually no fogging. On the other hand, in Experimental Example 3 (fiber board having a water content of 5.67) in which kenaf fibers and resin fibers were used in combination, the gloss ratio decreased to 0.77, and fogging was confirmed. On the other hand, in Experimental Example 4 (fiber board having a moisture content of 1.16%) in which the moisture content was reduced via the reduction step R3, the glossiness ratio was 0.97, which was the same result as in Experimental Examples 1 and 2. The result was that there was virtually no fogging. From these results, it was shown that the water contained in the kenaf fiber induces fogging, and that the decrease in water content has a remarkable antifogging effect.

The present invention is widely used in vehicle-related fields such as automobiles, ship-related fields, aircraft-related fields, construction-related fields, and the like. The fiber board obtained by the present invention is suitable as an interior material, an exterior material, a structural material and the like in the above fields. Among the above-mentioned vehicle-related fields, examples of automobile supplies include automobile interior materials, automobile instrument panels, automobile exterior materials, and the like. Specifically, door base materials, package trays, pillar garnishes, switch bases, quarter panels, armrest core materials, automobile door trims, seat structural materials, seat backboards, ceiling materials, console boxes, automobile dashboards, etc. Instrument panels, deck trims, bumpers, spoilers, cowlings and the like. Further, for example, interior materials such as buildings and furniture, exterior materials and structural materials can be mentioned. That is, door surface materials, door structural materials, surface materials for various furniture (desks, chairs, shelves, chests of drawers, etc.), structural materials, and the like can be mentioned. Other examples include a packaging body, an accommodating body (tray, etc.), a protective member, and a partition member.

10; fiber mat, 10a; plant fiber, 10b; binder resin,
11A, 11B; web (coarse web), 11C; laminated web,
20; fiber board, 20a; plant fiber, 20b; binder resin,
30; Vehicle interior materials,
31; base material layer, 31a; plant fiber, 31b; binder resin,
32; epidermis layer,
41; Measurement sample, 42; Tall beaker, 43; Oil bath, 44; Glass plate,
5; Needle punch machine,
6; Cutting machine,
7; Hot press machine,
8; Heating device,
9; Cold press,
R1; mat forming process,
R2; board forming process,
R3; reduction process,
R4; molding step, R41; heating step, R42; shaping step.

Claims (6)

A mat forming process for forming a fiber mat containing plant fibers and resin fibers,
A board forming step of heating and pressurizing the fiber mat to obtain a fiber board,
A method for producing a fiber board, which comprises a reduction step of reducing the water content contained in the fiber mat and / or the fiber board. The method for manufacturing a fiber board according to claim 1, wherein the reduction step is a step of reducing water content by heating. The method for manufacturing a fiber board according to claim 1 or 2, wherein the reduction step is a step of reducing the moisture content of the fiber mat or the fiber board to less than 3%. A method for reducing fogging of vehicle interior materials having a base material layer in which plant fibers are bound to each other by a binding resin.
A method for reducing fogging of a vehicle interior material, which comprises a reduction step for reducing the water content contained in the base material layer. The fogging reduction method according to claim 4, wherein the reduction step is a step of reducing water content by heating. The fogging reduction method according to claim 4 or 5, wherein the reduction step is a step of reducing the water content of the base material layer to less than 3%.

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