Vehicle interior / exterior part and manufacturing method thereof

Abstract

To provide a vehicle interior / exterior article in which a body and a sound absorber are integrally molded without applying pre-processing of the sound absorber and post-processing after product molding and the sound absorber is hardly peeled, and to provide a production method of the same.SOLUTION: A vehicle interior / exterior article 10 comprises: a substrate layer 11 as a fiber molded body containing a thermoplastic synthetic resin 12; and a sound absorbing layer 15 in which a fiber web 16 entangled containing a thermoplastic synthetic fiber 18 and a cover layer 17 as a nonwoven fabric containing the thermoplastic synthetic fiber 18 are laminated. The sound absorbing layer 15 includes: an adhesion part 21 coagulated in a state that the fiber web 16 is laminated on one surface of the substrate layer 11, and the thermoplastic synthetic fiber 18 on a surface in contact with the substrate layer 11 and the thermoplastic synthetic resin 12 of the substrate layer 11 are thermally adhered; a sound absorbing part 22 retaining a fiber web state without fusing of the thermoplastic synthetic fiber 18; and a compressed part 23 heat-compressed in a state that the substrate layer 11, the fiber web 16, and the cover layer 17 are pressed in a thickness direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an interior or exterior vehicle part and a method for manufacturing an interior or exterior vehicle part. [Background technology]

[0002] Conventionally, interior and exterior vehicle parts are made using injection moldings, polyester fiber materials, glass fiber base materials, etc., and sound-absorbing materials are sometimes attached to the back side of the interior and exterior parts for the purpose of quieting the interior of the vehicle. Sound-absorbing materials include felt made of wool or polyester fiber, felt mainly made of polypropylene melt-blown fiber, etc. Also, ultrasonic spot welding is used to attach the sound-absorbing materials.

[0003] For example, Patent Document 1 discloses a sound absorbing material for automobiles, which is formed by laminating a needle-punched nonwoven fabric containing polyethylene terephthalate and polypropylene, and a melt-blown nonwoven fabric containing polypropylene. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6444569 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, sound-absorbing materials used in interior and exterior vehicle parts are laminated with a thin nonwoven fabric to protect against water, sand, wind pressure, etc., and may be crushed at the ends by hot pressing to prevent fraying and fraying. In this case, a pre-processing step is required in the manufacturing process of the interior and exterior parts to crush the cut ends of the sound-absorbing material in advance. In addition, spot welding is performed to bond (weld) the sound-absorbing material to the main body of the molded interior and exterior part as a post-processing step, but there is a concern that the sound-absorbing material may peel off from the interior and exterior part at the welded parts.

[0006] The present invention has been devised in consideration of these points, and the problem that the present invention aims to solve is to provide an interior or exterior vehicle part in which the sound-absorbing material is molded as an integrated part with the main body of the interior or exterior part, without the need for pretreatment of the sound-absorbing material or post-processing after molding of the interior or exterior part, and in which the sound-absorbing material is not easily peeled off, and a method for manufacturing the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention takes the following measures. First, a vehicle interior / exterior part according to a first invention has a sound absorbing layer in which a base layer which is a planar fiber molding containing a thermoplastic synthetic resin, a planar fiber web containing thermoplastic synthetic fibers and entangled, and a cover layer which is a planar nonwoven fabric containing thermoplastic synthetic fibers on at least one side of the fiber web are laminated, and the sound absorbing layer has an adhesive part in which the fiber web is laminated on one side of the base layer and the thermoplastic synthetic fibers on the side in contact with the base layer and the thermoplastic synthetic resin of the base layer are solidified in a state of being thermally bonded, a sound absorbing part in which the thermoplastic synthetic fibers are not melted and the fiber web state of being entangled is maintained at a position separated from the base layer from the adhesive part, and a compression part in which the base layer, the fiber web, and the cover layer are thermally compressed in a state of being compressed in the thickness direction.

[0008] According to the first invention, the interior and exterior product for a vehicle is formed by laminating a base material layer, which is a planar fiber molding containing a thermoplastic synthetic resin, and a sound absorbing layer having a planar fiber web containing thermoplastic synthetic fibers and a cover layer, and bonding the surfaces of these layers together at a predetermined location. In the bonding portion, the thermoplastic synthetic fibers on the surface of the sound absorbing layer that contacts the base material layer and the thermoplastic synthetic resin of the base material layer are solidified in a thermally bonded state. As a result, the surface where the base material layer and the sound absorbing layer contact is bonded over a wide area. In addition, the interior and exterior product for a vehicle is formed by molding a compression portion in which the base material layer, the fiber web, and the cover layer are thermally bonded in a state compressed in the thickness direction, and a sound absorbing portion is formed in which the thermoplastic synthetic fibers are not melted and the fiber web state in which they are intertwined is maintained. In this way, the product in which the laminated base material layer and the sound absorbing layer are integrally molded has the bonding portion and the compression portion, so that the base material layer and the sound absorbing layer are firmly bonded to each other. Therefore, it is possible to prevent the sound absorbing layer from fraying, fraying, and peeling from the interior and exterior product for a vehicle.

[0009] A second invention relates to an interior or exterior vehicle part according to the first invention, wherein the pressure-bonded portion is provided at a plurality of points in a dotted or linear manner on a plane of the laminated base material layer and sound-absorbing layer.

[0010] According to the second invention, the interior / exterior part for a vehicle has a plurality of pressure-bonded portions provided in a dot-like or linear manner on the plane of the base material layer and the sound-absorbing layer. Increasing the number of pressure-bonded portions in this manner can improve the function of preventing fraying and peeling of the sound-absorbing layer. Also, the adhesive strength of the adhesive portion of the product can be maintained while adjusting the degree of compression in the sound-absorbing portion. For example, by reducing the degree of compression in the sound-absorbing portion, the thickness of the base material layer and the sound-absorbing layer can be made thicker. In this case, the melting of the thermoplastic synthetic fiber of the sound-absorbing layer is reduced, so that the adhesive strength of the adhesive portion in the sound-absorbing portion is reduced, but the decrease in the sound absorption coefficient can be suppressed. On the other hand, the base material layer and the sound-absorbing layer are suitably compressed and thermocompressed in the pressure-bonded portion, ensuring the adhesive strength.

[0011] A third invention is an interior or exterior vehicle part according to the first or second invention, wherein the pressure-bonded portion is provided in a dotted or linear pattern at multiple locations along the periphery of the sound-absorbing layer, or around the entire circumference.

[0012] According to the third aspect of the present invention, the interior / exterior part for a vehicle has a pressure-bonded portion provided in a plurality of dots or lines along the periphery of the sound-absorbing layer, or over the entire periphery. This allows the sound-absorbing layer to be more firmly thermocompressed to the base layer at the periphery, preventing fibers from falling off from the ends of the sound-absorbing layer. Furthermore, it is possible to prevent fraying or peeling at the ends of the sound-absorbing layer, and to enhance protection of the product against dust, sand, water, etc.

[0013] A fourth invention is a method for manufacturing interior and exterior vehicle parts, the method including the steps of: heating a base layer which is a planar fiber molding containing thermoplastic synthetic resin; laminating an unheated sound absorbing layer, which is a laminate of a planar fiber web containing thermoplastic synthetic fibers and an intertwined cover layer which is a planar nonwoven fabric containing thermoplastic synthetic fibers on at least one side of the fiber web, onto the heated base layer, and thermally bonding the thermoplastic synthetic resin of the base layer and the thermoplastic synthetic fibers of the fiber web at surfaces where the layers contact each other; molding a molding step in which the laminated base layer and sound absorbing layer are sandwiched from both sides between a pair of molding dies having an upper die and a lower die, and pressurized while cooling to mold the laminate; and a pressing step in which the base layer, the fiber web, and the cover layer are compressed in the thickness direction and thermally pressed to form a pressed portion, thereby pressing the sound absorbing layer onto the base layer, the adhesion step and the pressing step can be performed together with the molding step.

[0014] According to the fourth invention, in the bonding step, the preheated base layer containing a thermoplastic synthetic resin and the sound absorbing layer containing a thermoplastic synthetic fiber are pressed from both sides by a mold in a laminated state. The heat of the base layer causes the thermoplastic synthetic resin contained in the base layer and the thermoplastic synthetic fiber contained in the sound absorbing layer to be thermally bonded, so that the surfaces of the base layer and the sound absorbing layer that contact each other are bonded over a wide area. In the molding step, the base layer and the sound absorbing layer are sandwiched between a pair of molds to be molded into a predetermined shape. In addition, in the pressure bonding step, the base layer, the fiber web, and the cover layer at a predetermined location of the sound absorbing layer are compressed in the thickness direction, so that a part of the thermoplastic synthetic fiber contained in the sound absorbing layer is melted and crushed by the heat of the base layer, and the pressure bonded part is formed. By performing these steps together, the process of bonding the sound absorbing layer to the base layer and the process of crushing the sound absorbing layer can be performed at the same time in the process of molding the interior and exterior product for a vehicle, and an interior and exterior product for a vehicle in which the sound absorbing material is not easily peeled off can be molded.

[0015] A fifth invention is a method for manufacturing interior and exterior vehicle parts according to the fourth invention, wherein one of the pair of molding dies has a recess in which the gap between the upper die and the lower die which face each other when the pair of molding dies are closed is larger than the thickness dimension of the base material layer, and a convex portion in which the gap is smaller than the thickness dimension of the base material layer, and a sound absorbing portion in which the thermoplastic synthetic fibers are not melted and are kept in an entangled fiber web state is molded in the recess, and the pressure-bonding portion is molded in the convex portion, and after the pair of molding dies are released, the thickness of the sound absorbing portion returns to a thickness greater than that of the pressure-bonding portion due to the repulsive force of the fibers contained in the fiber web.

[0016] According to the fifth invention, one of the pair of molds has a recess in which the gap between the upper and lower molds facing each other when the pair of molds is closed is larger than the thickness dimension of the base material layer, and a convex portion in which the gap is smaller than the thickness dimension of the base material layer. When the laminated base material layer and the sound absorbing layer are sandwiched from both sides by the molds, the sound absorbing layer is compressed together with the base material layer at the portion where it contacts the convex portion. Therefore, a part of the thermoplastic synthetic fiber contained in the sound absorbing layer is melted by the heat of the base material layer, and a pressure-bonded portion is formed. Also, at the portion where the sound absorbing layer contacts the concave portion, the compression of the sound absorbing layer is relatively small, and the heat of the base material layer is difficult to transmit. Therefore, the thermoplastic synthetic fiber contained in the sound absorbing layer does not melt, and the sound absorbing portion is formed in which the intertwined fiber web state is maintained. As a result, after the pair of molds are released, the thickness of the sound absorbing portion is restored by the repulsive force of the fiber contained in the fiber web, and the required thickness of the sound absorbing material can be maintained even after molding.

[0017] A sixth invention is a method for producing an interior or exterior vehicle part according to the fourth or fifth invention, wherein the pressure bonding step further comprises welding the pressure bonded portion by using another heat source.

[0018] According to the sixth aspect of the present invention, the pressure-bonded portion of the vehicle interior / exterior part is further heated to weld the pressure-bonded portion, thereby making it possible to further strengthen the adhesive bond between the base material layer and the sound absorbing layer. Effect of the Invention

[0019] By using the configurations or processes of each of the above-mentioned inventions, the present invention can provide an interior or exterior vehicle part in which the main body of the interior or exterior part and the sound-absorbing material are molded as an integrated unit, without the need for pretreatment of the sound-absorbing material or post-processing after molding of the interior or exterior part, and in which the sound-absorbing material is not easily peeled off, and a manufacturing method thereof. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a diagram showing a laminated state of a base material layer and a sound absorbing layer of the vehicle interior / exterior part according to the embodiment. [Diagram 2] 5 is a cross-sectional view showing a state in which a base layer and a sound absorbing layer are placed between an upper mold and a lower mold in a manufacturing process according to an embodiment. FIG. [Diagram 3] 5A to 5C are cross-sectional views each showing a state in which a base layer and a sound absorbing layer are pressed and molded by a molding die in a manufacturing process according to an embodiment. [Figure 4] 5 is a cross-sectional view showing a schematic state of the base layer and the sound absorbing layer after the molding die is opened in the manufacturing process according to the embodiment. FIG. [Diagram 5] 1 is a diagram showing a molded product of an interior or exterior vehicle part according to an embodiment of the present invention; [Figure 6] FIG. 2 is a diagram showing a typical lamination state of a base material layer and a sound absorbing layer in the measurement of the sound absorption coefficient of the vehicle interior / exterior parts according to Example 1 and the comparative example. [Figure 7] 4 is a diagram showing the sound absorbing performance of the vehicle interior / exterior part according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. As an interior or exterior vehicle part and a manufacturing method for an interior or exterior vehicle part of this embodiment, an undercover, which is an exterior material for a vehicle, will be described as an example of the interior or exterior vehicle part. The undercover 10 (exterior material for a vehicle) according to this embodiment has a base material layer 11 and a sound absorbing layer 15 laminated together.

[0022] <Composition of vehicle exterior materials> 1 and 5, the base layer 11 is a porous fibrous body containing a thermoplastic synthetic resin 12, and is a planar fibrous molded body that is heated and then cold-formed. The base layer 11 may contain a fiber reinforcing material. The base layer 11 can be manufactured by a known manufacturing method such as a dry method using needle punching or a wet papermaking method.

[0023] The thermoplastic synthetic resin 12 may be selected from olefins such as polypropylene, polyesters such as polyethylene terephthalate, polyamides, and the like.

[0024] As the fiber reinforcing material, glass fiber, basalt fiber, carbon fiber, as well as natural fibers such as kenaf (western hemp) and bamboo can be appropriately selected.

[0025] An example of the substrate layer 11 is a fiber substrate (LWRT=Low Weight Reinforced Thermoplastics) that uses polypropylene fiber, which is a thermoplastic synthetic resin 12, as a binder fiber and glass fiber as a fiber reinforcement. An example of the substrate layer 11 that does not contain a fiber reinforcement is a needle-punched nonwoven substrate (molded nonwoven substrate) that uses polyethylene terephthalate fiber and binder fibers such as low melting point polyester fiber. These substrates can also be made into a multi-layer structure by bonding a nonwoven substrate or film separately depending on the needs for design, durability, etc.

[0026] The sound absorbing layer 15 has a planar fiber web 16 containing thermoplastic synthetic fibers 18 and entangled therewith, and a cover layer 17 which is a planar nonwoven fabric containing thermoplastic synthetic fibers 18, and is configured such that the fiber web 16 is laminated on one side of the base material layer 11, and the cover layer 17 is further laminated thereon.

[0027] The thermoplastic synthetic fibers 18 in the fiber web 16 and cover layer 17 can be selected from the group consisting of polyethylene fibers, polypropylene fibers, polystyrene fibers, polyester fibers, and mixtures thereof. Examples of the fiber web 16 include laminated felts of polypropylene fibers, polyester fibers, and the like, needle punch mats, meltblown fiber bodies, and mixtures thereof. Products such as Thinsulate (registered trademark) may also be used. Polypropylene fibers are preferred because they are hydrophobic and therefore water does not easily penetrate between the fibers, and sound absorbing properties can be maintained during use.

[0028] The density and thickness of the sound absorbing layer 15 may vary depending on the location of the vehicle. When a high-density, thick nonwoven fabric is used for the sound absorbing layer 15, better sound absorbing performance is exhibited. The fiber diameter and fiber length of the thermoplastic synthetic fibers 18 used in the fiber web 16 can be appropriately selected.

[0029] The cover layer 17 is a planar nonwoven fabric containing thermoplastic synthetic fibers 18, and is laminated on the surface of the fiber web 16 that is not in contact with the base layer 11. The cover layer 17 protects the fiber web 16 of the sound absorbing layer 15. An example of the cover layer 17 is a polypropylene spunbond nonwoven fabric. Since polyolefins such as polyethylene and polypropylene have excellent chemical stability, the vehicle exterior material 10 in which the fiber web 16 of the sound absorbing layer 15 is protected by the cover layer 17 has high durability against exposure to the atmosphere outside the vehicle, exhaust gas, salt, corrosive gas, etc. In addition, by using a ventilation-controlled nonwoven fabric, the sound absorbing performance against the incidence of sound from the sound absorbing layer 15 side can be improved.

[0030] The cover layer 17 may be laminated on one side of the fiber web 16, or on both sides of the fiber web 16. By laminating the cover layer 17 on both sides of the fiber web 16, either side may be in contact with the base layer 11, and therefore the cover layer 17 can be used in a vehicle exterior material 10 having a left-right inverted shape.

[0031] The sound absorbing layer 15 has an adhesive portion 21 in which the thermoplastic synthetic resin 12 contained in the base material layer 11 and the thermoplastic synthetic fibers 18 contained in the fiber web 16 are solidified in a thermally bonded state on the surface in contact with the base material layer 11. As a result, the surfaces in contact with the base material layer 11 and the sound absorbing layer 15 are thermally bonded over a wide area. The adhesive portion 21 may also be configured to be thermally bonded over the entire surface in contact with the base material layer 11 and the sound absorbing layer 15. By bonding over a wide area of ​​the surface in this manner, it is possible to form a vehicle exterior material 10 that is less likely to peel off than when the sound absorbing layer 15 is spot-welded.

[0032] The sound absorbing layer 15 has a sound absorbing section 22 in which the thermoplastic synthetic fibers 18 are not melted and are kept in an entangled fiber web state at a position farther from the base layer 11 than the adhesive section 21. The sound absorbing layer 15 also has a pressure-bonded section 23 in which the base layer 11, the fiber web 16, and the cover layer 17 are heat-bonded in a state compressed in the thickness direction. Specifically, the fiber web 16 and the cover layer 17 of the sound absorbing layer 15 are heat-melted and solidified in a crushed state, and are heat-bonded integrally with the base layer 11. Therefore, the thickness of the pressure-bonded section 23 is thinner than the thickness of the base layer 11 in the sound absorbing section 22. The pressure-bonded section 23 may also be configured to be welded by another heat source such as ultrasonic welding. This allows the vehicle exterior material 10 to be formed in the pressure-bonded section 23 with stronger pressure bonding.

[0033] The pressure-bonded portion 23 is provided in a dot-like or linear manner at a plurality of locations on the plane of the laminated base layer 11 and sound-absorbing layer 15. Furthermore, the pressure-bonded portion 23 is provided along the entire periphery of the sound-absorbing layer 15. By providing the pressure-bonded portion 23 on the periphery of the sound-absorbing layer 15, fraying or peeling at the end of the sound-absorbing layer 15 can be suppressed, and the intrusion of dust, sand, water, and the like can be suppressed. The pressure-bonded portion 23 may be configured to be provided in a dot-like or linear manner at a plurality of locations along the periphery of the sound-absorbing layer 15. Furthermore, the pressure-bonded portion 23 may be provided in a fine protrusion-like shape at a plurality of locations. The pressure-bonded portion 23 can be provided at any location depending on the shape of the product, etc.

[0034] <Manufacturing process for vehicle exterior materials> Next, a method for producing the vehicle exterior material (vehicle interior / exterior product) according to this embodiment will be described. The method for producing the vehicle exterior material includes a heating step, a bonding step, a molding step, and a pressure bonding step.

[0035] In this embodiment, the molding dies 31, 32 used for molding the vehicle exterior material 10 are a pair, and have an upper die 31 and a lower die 32. The lower die 32 is provided with a recess 33 and a protrusion 34. The recess 33 is configured such that the gap La between the upper die 31 and the lower die 32 facing each other when the pair of molding dies 31, 32 are closed is larger than the thickness dimension of the base material layer 11, and the protrusion 34 is configured such that the gap Lb between the upper die 31 and the lower die 32 is smaller than the thickness dimension of the base material layer 11 (see FIG. 3). The gaps La, Lb between the upper die 31 and the lower die 32 of the molding dies are set so that an appropriate molding pressure is applied according to the material and basis weight of the base material layer 11 and the sound absorbing layer 15. For example, if the gap La in the recess 33 is made too small, the sound absorbing layer 15 is excessively compressed and the sound absorbing performance is reduced, and if the gap La is made large, the molding pressure on the base material layer 11 is reduced, so the size of the gap La is set within a range in which an appropriate molding pressure is applied while maintaining the required sound absorbing performance.

[0036] In the heating step, the base layer 11 is heated by a far-infrared heater, an oven, or the like.

[0037] Next, as shown in FIG. 2, the unheated sound absorbing layer 15 in which the fiber web 16 and the cover layer 17 are laminated is set in the lower die 32 of the molding die. The cover layer 17 of the set sound absorbing layer 15 is in contact with the lower die 32. The heated base layer 11 is laminated on the sound absorbing layer 15 between the molding dies 31 and 32. The thermoplastic synthetic resin 12 of the base layer 11 and the thermoplastic synthetic fiber 18 of the fiber web 16 are thermally bonded to the surfaces of the base layer 11 and the sound absorbing layer 15 that are in contact with each other. The process of thermally bonding the surfaces of the laminated base layer 11 and the sound absorbing layer 15 that are in contact with each other in this manner corresponds to the "bonding process" according to the present invention. The bonding process can be performed together with the molding process, since the sound absorbing layer 15 is set in the molding dies 31 and 32 and the base layer 11 is laminated.

[0038] As shown in FIG. 3, the laminated base material layer 11 and sound absorbing layer 15 are pressed while being cooled by being sandwiched between dies 31 and 32 from both sides. As a result, the vehicle exterior material 10 is molded into a predetermined shape. In addition, in the convex portion 34, since the gap Lb between the upper die 31 and the lower die 32 is smaller than the thickness of the base material layer 11, the base material layer 11, the fiber web 16, and the cover layer 17 are compressed in the thickness direction. As a result, when the gap Lb is sufficiently small, the heat of the heated base material layer 11 is transferred to the fiber web 16 and the cover layer 17, and a part of the thermoplastic synthetic fibers 18 contained therein is thermally melted. Due to this thermal melting, the sound absorbing layer 15 is thermally bonded to the base material layer 11 in a crushed state, and the bonded portion 23 is formed. The bonded portion 23 may further be ultrasonically welded. In this way, by welding the bonded portion 23 with a separate heat source, the bonded portion 23 becomes stronger. The welding using a different heat source may be, for example, infrared welding, welding using an electric heater, hot air, or the like.

[0039] Furthermore, in the recess 33, the gap La between the upper mold 31 and the lower mold 32 is larger than the thickness of the base layer 11, so the compression rate of the sound absorbing layer 15 is relatively small, and the heat of the base layer 11 is less likely to be transmitted to the sound absorbing layer 15. As a result, the thermoplastic synthetic fibers 18 do not melt and are maintained in an entangled fiber web state, and the sound absorbing section 22 is formed. The sound absorbing section 22 compressed to fit the gap La between the upper mold 31 and the lower mold 32 in the recess 33 is restored to its thickness by the repulsive force of the fibers contained in the fiber web 16 after the pair of molding dies 31, 32 are released, as shown in FIG. 4. The thickness of the sound absorbing section 22 becomes thinner than the original thickness. By maintaining the thickness of the sound absorbing section 22 at a constant level or more in this manner, it is possible to suppress a decrease in sound absorbing performance.

[0040] The dimensions of the gaps La and Lb between the upper mold 31 and the lower mold 32 are set arbitrarily. When the gap La in the recess 33 of the lower mold 32 is made small, the restoration of the thickness of the sound absorbing layer 15 is reduced and the thickness of the base layer 11 is reduced. On the other hand, when the gap La in the recess 33 is made large, the compression of the sound absorbing layer 15 is reduced, and the thickness of the sound absorbing layer 15 and the base layer 11 can be made thicker, but the adhesive strength of the adhesive portion 21 is weakened. Also, when the gap La in the recess 33 is made excessively large, the base layer 11 cannot be molded into an appropriate shape due to insufficient molding pressure applied to the base layer 11. Therefore, the size of the gap La is set within a range where an appropriate molding pressure is applied while maintaining the required sound absorbing performance. Here, when the gap Lb in the protrusion 34 of the lower mold 32 is made sufficiently small to compress the sound absorbing layer 15, the compression portion 23 in which the sound absorbing layer 15 and the base layer 11 are firmly compressed is formed. By providing the pressure-bonding portion 23 in this manner, the adhesive strength between the sound absorbing layer 15 and the base material layer 11 can be ensured.

[0041] As described above, the process of sandwiching the laminated base material layer 11 and sound absorbing layer 15 from both sides between a pair of molds 31 and 32 and applying pressure to mold the vehicle exterior material 10 corresponds to the "molding process" according to the present invention. The process of compressing the base material layer 11 and sound absorbing layer 15 in the thickness direction to mold the pressure-bonded portion 23 corresponds to the "pressure-bonding process" according to the present invention. The pressure-bonding process is performed in conjunction with the molding process to mold the pressure-bonded portion 23 on the base material layer 11 and sound absorbing layer 15 sandwiched between the molds 31 and 32. Therefore, the process of thermally bonding the sound absorbing layer 15 to the base material layer 11, the process of crushing the sound absorbing layer 15 and thermally pressing it to the base material layer 11, and the molding of the vehicle exterior material 10 can be performed at the same time.

[0042] The manufacturing process for the vehicle exterior material according to this embodiment produces a vehicle exterior material 10 in which the base material layer 11 and the sound absorbing layer 15 are integrally formed. The vehicle exterior material 10 is attached to the vehicle as an undercover in a state in which it is upside down as shown in FIG.

[0043] Thus, according to the vehicle exterior material 10 according to the embodiment, the base material layer 11, which is a planar fiber molding containing the thermoplastic synthetic resin 12, the sound absorbing layer 15 having the planar fiber web 16 containing the thermoplastic synthetic fibers 18, and the cover layer 17 are laminated, and their surfaces are thermally bonded to each other at a predetermined location. In the bonding portion 21, the thermoplastic synthetic fibers 18 on the surface of the sound absorbing layer 15 in contact with the base material layer 11 and the thermoplastic synthetic resin 12 of the base material layer 11 are solidified in a thermally bonded state. As a result, the surface where the base material layer 11 and the sound absorbing layer 15 are in contact is bonded over a wide area. In addition, the vehicle exterior material 10 is formed with a compression portion 23 in which the base material layer 11, the fiber web 16, and the cover layer 17 are thermally compressed in a state compressed in the thickness direction, and a sound absorbing portion 22 in which the thermoplastic synthetic fibers 18 are not melted and the fiber web state where they are entangled is maintained is formed. In this manner, the product in which the laminated base material layer 11 and sound absorbing layer 15 are integrally molded has the adhesive portion 21 and the pressure-bonded portion 23, so that the base material layer 11 and the sound absorbing layer 15 are firmly thermally bonded together. This makes it possible to prevent the sound absorbing layer 15 from becoming frayed or coming off from the vehicle exterior material 10.

[0044] In addition, the vehicle exterior material 10 has the pressure-bonded parts 23 provided in a dot-like or linear manner at multiple locations on the plane of the base material layer 11 and the sound-absorbing layer 15. Increasing the number of pressure-bonded parts 23 in this manner can improve the function of preventing the sound-absorbing layer 15 from fraying or peeling. In addition, the adhesive strength of the adhesive part 21 of the product can be maintained while adjusting the degree of compression in the sound-absorbing part 22. For example, the thickness of the base material layer 11 and the sound-absorbing layer 15 can be made thicker by reducing the degree of compression of the sound-absorbing part 22, that is, by increasing the gap La in the recess 33 of the molding dies 31 and 32. In this case, the adhesive strength of the adhesive part 21 of the sound-absorbing part 22 is reduced because the thermoplastic synthetic fiber 18 of the sound-absorbing layer 15 melts less, but the decrease in the sound absorption coefficient can be suppressed. On the other hand, the base material layer 11 and the sound-absorbing layer 15 are suitably compressed and thermocompressed in the pressure-bonded part 23, ensuring the adhesive strength.

[0045] Also, by providing the pressure-bonded portions 23 at a plurality of points or lines along the periphery of the sound absorbing layer 15, the sound absorbing layer 15 is more firmly thermocompressed to the base material layer 11 at the periphery, thereby preventing fraying or peeling at the ends of the sound absorbing layer 15 and improving product protection against dust, sand, water, etc. Furthermore, by providing the pressure-bonded portions 23 all around the periphery of the sound absorbing layer 15, it is possible to prevent fibers from spilling out from the ends of the sound absorbing layer 15.

[0046] In the manufacturing process of the vehicle exterior material 10 according to the embodiment, in the bonding step, the preheated base layer 11 containing the thermoplastic synthetic resin 12 and the sound absorbing layer 15 containing the thermoplastic synthetic fiber 18 are pressed from both sides by the molding dies 31, 32 in a laminated state. The thermoplastic synthetic resin 12 contained in the base layer 11 and the thermoplastic synthetic fiber 18 contained in the sound absorbing layer 15 are thermally bonded by the heat of the base layer 11, so that the contact surfaces of the base layer 11 and the sound absorbing layer 15 are bonded to each other over a wide range. In the molding step, the base layer 11 and the sound absorbing layer 15 are sandwiched between a pair of molding dies 31, 32 and cold molded into a predetermined shape. In addition, in the pressure bonding step, the base layer 11, the fiber web 16, and the cover layer 17 at a predetermined location of the sound absorbing layer 15 are compressed in the thickness direction, so that a part of the thermoplastic synthetic fiber 18 contained in the sound absorbing layer 15 is melted and crushed by the heat of the base layer 11, and the pressure bonding portion 23 is formed. By combining these steps, the process of adhering the sound-absorbing layer 15 to the base material layer 11 and the process of crushing the sound-absorbing layer 15 can be carried out simultaneously in the process of forming the vehicle exterior material 10, and a vehicle exterior material 10 can be formed in which the sound-absorbing layer 15 is less likely to peel off.

[0047] The lower die 32 of the mold has a recess 33 in which the gap La between the upper die 31 and the lower die 32 facing each other when the pair of molds 31, 32 are closed is larger than the thickness dimension of the base material layer 11, and a protrusion 34 in which the gap Lb is smaller than the thickness dimension of the base material layer 11. When the laminated base material layer 11 and the sound absorbing layer 15 are sandwiched from both sides by the molds 31, 32, the sound absorbing layer 15 is compressed together with the base material layer 11 at the portion contacting the protrusion 34. Therefore, a part of the thermoplastic synthetic fiber 18 contained in the sound absorbing layer 15 is melted by the heat of the base material layer 11, and the pressure-bonded portion 23 is formed. In addition, at the portion where the sound absorbing layer 15 is in contact with the recess 33, the compression of the sound absorbing layer 15 is relatively small, and the heat of the base material layer 11 is not easily transmitted. Therefore, the thermoplastic synthetic fiber 18 contained in the sound absorbing layer 15 does not melt, and the sound absorbing portion 22 in which the intertwined fiber web state is maintained is formed. As a result, after the pair of molding dies 31, 32 are released, the thickness of the sound absorbing section 22 is restored by the repulsive force of the fibers contained in the fiber web 16, and the required thickness of the sound absorbing layer 15 can be maintained even after molding.

[0048] The dimensions of the gaps La, Lb between the upper and lower dies 31, 32 of the molding dies 31, 32 are set according to the materials and basis weight of the base material layer 11 and the sound absorbing layer 15. Setting the dimensions of the gaps La, Lb within an appropriate range prevents the sound absorbing layer 15 from being excessively compressed, which would result in a decrease in sound absorbing performance, and allows an appropriate molding pressure to be applied to the base material layer 11. This makes it possible to mold a vehicle exterior material 10 that maintains sufficient sound absorbing performance and pressure bonding strength.

[0049] The pressure-bonded portion 23 of the vehicle exterior material 10 can be further welded by another heat source such as ultrasonic welding, thereby further strengthening the adhesive bond between the base material layer 11 and the sound-absorbing layer 15. Therefore, even if the base material layer 11 and the sound-absorbing layer 15 have different basis weights or different shapes, it is possible to prevent the occurrence of areas where the pressure bonding is insufficient.

[0050] By using the configuration and manufacturing process of the vehicle exterior material 10 according to the above embodiment, it is possible to provide a vehicle exterior material 10 in which the base material layer 11 and the sound-absorbing layer 15 of the vehicle exterior material 10 are molded in an integrated state, without the need for pretreatment of the sound-absorbing layer 15 or post-processing after the exterior material is molded, and in which the sound-absorbing layer 15 is not easily peeled off, and a manufacturing method thereof.

[0051] The present invention will be specifically described below with reference to examples and comparative examples.

[0052] [Example 1] A vehicle undercover material (1400 gsm basis weight) was used as the base material layer 11, which is a multilayer fiber base material in which a needle-punched nonwoven fabric was bonded to a needle-punched fiber base material of glass fiber and polypropylene fiber, and a sound-absorbing material (230 gsm basis weight, approximately 25 mm thick) mainly composed of melt-blown polypropylene fiber was used as the sound-absorbing layer 15. Polypropylene spunbond nonwoven fabric was laminated on both sides of the sound-absorbing layer 15 as the cover layer 17. Only the base layer 11 was heated to a surface temperature of 210° C., and the unheated sound absorbing layer 15 was laminated thereon, and compressed and molded at room temperature. Compression-bonded portions 23 were provided at four locations. The gaps La, Lb between the upper mold 31 and the lower mold 32 of the mold were 8 mm at the recessed portion 33 and 2 mm at the protruding portion . In the molded product of the vehicle exterior material 10, the thickness of the base material layer 11 is about 5 mm plus the thickness of the sound absorbing layer 15 is about 15 mm in the sound absorbing section 22. In addition, the thickness of the pressure-bonded section 23 is 2 mm because the base material layer 11 and the sound absorbing layer 15 are compressed, and they are appropriately pressure-bonded.

[0053] [Comparative Example] The base layer 41 was made of the same vehicle undercover material as in Example 1, and was molded to a thickness of 7 mm. The sound absorbing layer 45 was made of a sound absorbing material (basis weight 150 gsm, thickness approximately 13 mm) mainly made of polypropylene meltblown fibers (see FIG. 6). Polypropylene spunbond nonwoven fabric was laminated on both sides of the sound absorbing layer 45 as the cover layer 17. The sound absorbing layer 45 is simply laminated on the base material layer 41, and no pressure-bonded portion is provided. The thickness of the laminated fiber layer 40 (sound absorbing portion) is the sum of the thickness of the base material layer 41 (7 mm) and the thickness of the sound absorbing layer 45 (approximately 13 mm).

[0054] <Sound absorption rate> The sound absorption coefficients of the molded product of the vehicle exterior material 10 according to Example 1 and the fiber layer 40 according to the comparative example are measured and compared. Specifically, assuming an evaluation of the sound absorption performance of road noise as an undercover, the sound absorption coefficient is measured from the base material layer 11, 41 side. This sound absorption coefficient is measured by the reverberation room method sound absorption coefficient according to the standard of JIS A 1409. As shown in FIG. 6, a spacer 51 is arranged, and the surface position of the base material layer 11, 41 is set at a height of 20 mm from the floor surface. FIG. 7 shows the sound absorption coefficients of Example 1 and the comparative example. The sound absorption coefficient for each sound range of Example 1 changes in the same tendency as the comparative example in the sound range of 315 to 2500 Hz. Example 1 shows a higher sound absorption coefficient than the comparative example in the sound ranges of 315 to 630 Hz and 4000 to 6300 Hz. Moreover, from 800 Hz to 3150 Hz, the sound absorption rate of Example 1 is reduced by only about 13% compared to the comparative example, and from 800 to 1000 Hz, the reduction is limited to about 8%. Thus, a significant reduction in the sound absorption performance of the vehicle exterior material 10 according to Example 1 is suppressed.

[0055] [Example 2] A vehicle undercover material (basis weight 1200 gsm) which is a needle-punched nonwoven fabric base material (molded nonwoven fabric) using polyethylene terephthalate fiber and binder fiber such as low-melting point polyester fiber was used as the base material layer 11, and a felt (basis weight 340 gsm, thickness about 20 mm) of meltblown polypropylene fiber and polyethylene terephthalate fiber was used as the sound absorbing layer 15. Note that polypropylene spunbond nonwoven fabric is laminated on both sides of the sound absorbing layer 15 as the cover layer 17. Only the base layer 11 was heated to a surface temperature of 210° C., and the unheated sound absorbing layer 15 was laminated thereon, and compressed and molded at room temperature. Compression-bonded portions 23 were provided at four locations. The gaps La, Lb between the upper mold 31 and the lower mold 32 of the mold were set to 5.5 mm at the recessed portion 33 and 1.5 mm at the protruding portion . In the molded product of the vehicle exterior material 10, the thickness of the base material layer 11 is about 3.5 mm plus the thickness of the sound absorbing layer 15 is about 13 mm in the sound absorbing section 22. In addition, the thickness of the pressure-bonded section 23 is 1.5 mm because the base material layer 11 and the sound absorbing layer 15 are compressed, and they are appropriately pressure-bonded.

[0056] [Example 3] The base material layer 11 and the sound absorbing layer 15 were made of a vehicle undercover material (basis weight 1200 gsm) and felt (basis weight 340 gsm, thickness approximately 20 mm) having the same configuration as in Example 2. Note that polypropylene spunbond nonwoven fabric was laminated on both sides of the sound absorbing layer 15 as a cover layer 17. Only the base layer 11 was heated to a surface temperature of 210° C., and the unheated sound absorbing layer 15 was laminated thereon, and compressed and molded at room temperature. Compression-bonded portions 23 were provided at four locations. The gaps La, Lb between the upper and lower dies 31, 32 of the mold were set to 4 mm at the recessed portion 33 and 1.5 mm at the protruding portion . In the molded product of the vehicle exterior material 10, the thickness of the base material layer 11 is about 2.5 mm plus the thickness of the sound absorbing layer 15 is about 10 mm in the sound absorbing section 22. In addition, the thickness of the pressure-bonded section 23 is 1.5 mm due to the compression of the base material layer 11 and the sound absorbing layer 15, and they are appropriately pressure-bonded.

[0057] The vehicle interior / exterior product according to the present invention is not limited to the appearance and configuration described in the above embodiment, and can be embodied in various other forms by various modifications, additions, deletions, and combinations of configurations without departing from the gist of the present invention.

[0058] The vehicle interior / exterior product according to the above embodiment may include both vehicle interior products and vehicle exterior products. The vehicle interior products may be applied to, for example, luggage trim, door trim, rear parcel shelf, deck board, trunk trim, pillar garnish, roof trim, etc. The vehicle exterior products may be applied to, for example, undercovers (engine undercovers, floor covers, etc.) and wheel house protectors for vehicle underfloors. [Explanation of symbols]

[0059] 10 Undercover (exterior material for vehicles) 11 Base material layer 12 Thermoplastic synthetic resin 15 Sound absorbing layer 16 Fiber Web 17 Cover Layer 18 Thermoplastic synthetic fibers 21 Adhesive part 22 Sound absorbing section 23 Crimping section 31 Molding mold (upper mold) 32 Molding mold (lower mold) 33 Recess 34 Convex La Gap in the recess Lb Gap at convex part

Claims

1. A method for manufacturing an interior or exterior vehicle part, comprising the steps of: A heating step of heating a substrate layer which is a planar fiber molding containing a thermoplastic synthetic resin; a bonding step of laminating an unheated sound absorbing layer, which is a laminate of a planar fiber web containing thermoplastic synthetic fibers and an intertwined fiber web and a cover layer which is a planar nonwoven fabric containing thermoplastic synthetic fibers on at least one surface of the fiber web, on the heated base layer, and thermally bonding the thermoplastic synthetic resin of the base layer and the thermoplastic synthetic fibers of the fiber web on their mutually contacting surfaces; a molding step of sandwiching the laminated base layer and the sound absorbing layer from both sides between a pair of molding dies having an upper die and a lower die, and pressurizing and molding the laminated base layer and the sound absorbing layer while cooling the laminated base layer and the sound absorbing layer; a compression step of compressing and heat-compressing the base layer, the fiber web, and the cover layer in a thickness direction to form a compression-bonded portion, thereby compressing the sound absorbing layer onto the base layer, and further fusing the compression-bonded portion with another heat source; The method for producing an interior or exterior vehicle part, wherein the adhesion step and the pressure-bonding step can be carried out simultaneously with the molding step.

2. A method for manufacturing an interior or exterior vehicle part according to claim 1, comprising: one of the pair of molds has a recess in which a gap between the upper mold and the lower mold that face each other when the pair of molds are closed is larger than a thickness dimension of the base material layer, and a protrusion in which the gap is smaller than the thickness dimension of the base material layer; A sound absorbing portion is formed in the recessed portion, in which the thermoplastic synthetic fibers are not melted and are kept in an entangled fiber web state, and the pressure-bonding portion is formed in the protruding portion, A method for manufacturing interior and exterior vehicle parts, wherein after the pair of molding dies are released, the sound-absorbing portion restores its thickness to a thickness greater than that of the pressure-bonded portion due to the repulsive force of the fibers contained in the fiber web.

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