Vehicle undercover and manufacturing method thereof

Abstract

To provide a lightweight undercover for vehicles that exhibits excellent durability against contact of a foreign matter and excellent sound absorbency at a low cost.SOLUTION: An integrally molded undercover 1 for vehicles comprises a base material layer 10, a first resin film layer 20, and a second resin film layer 30. The base material layer 10 includes inorganic fibers 11 and a solidified thermoplastic binder 12. The first resin film layer 20 is integrated with a surface 13a on the side of a road surface of the base material layer 10. The second resin film layer 30 exhibits air permeability and is integrated with a surface 13b on the side of a vehicle body of the base material layer 10. The first resin film layer 20 is thicker than the second resin film layer 30, and has plural orifices 21 through which air passes in a thickness direction D1. The undercover 1 for vehicles exhibits air permeability.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an integrally molded vehicle undercover and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art Vehicle undercovers such as engine undercovers and floor undercovers are attached to the underside of a vehicle body in order to improve the quietness inside the vehicle. The vehicle undercover disclosed in Patent Document 1 includes a base layer containing inorganic fibers and a solidified thermoplastic binder, an outer layer containing synthetic resin fibers and a solidified thermoplastic binder and integrated with the surface of the base layer facing the road surface, and a breathable synthetic resin layer that is integrated with the surface of the base layer facing the vehicle body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-44963 Summary of the Invention [Problem to be solved by the invention]

[0004] Vehicle undercovers must be durable against contact with stones and other foreign objects, have sound absorption properties against road and engine noise, and be lightweight to improve fuel economy.In addition, vehicle undercovers must also be cost-effective.

[0005] The present invention discloses a technology for providing a lightweight vehicle undercover at low cost that has good durability against contact with foreign objects and good sound absorption properties. [Means for solving the problem]

[0006] The vehicle undercover of the present invention is an integrally molded vehicle undercover, a substrate layer including inorganic fibers and a solidified thermoplastic binder; a first resin film layer integrated with the road surface side surface of the base material layer; a second resin film layer that is breathable and integrated with the vehicle body side surface of the base material layer, the first resin film layer is thicker than the second resin film layer and has a plurality of openings that allow air to circulate in a thickness direction; It has breathable properties.

[0007] Further, the present invention provides a method for producing an undercover for a vehicle, the undercover having breathability, the method comprising: a base material layer; a first resin film layer integrated with a surface of the base material layer facing a road surface; and a second resin film layer integrated with a surface of the base material layer facing a vehicle body, the method comprising: The present invention has an embodiment in which a laminated material is formed by stacking in this order a first resin film including a thermoplastic main resin film having a plurality of main openings and a thermoplastic secondary resin film thinner than the main resin film, a substrate including inorganic fibers and a thermoplastic binder, and a thermoplastic second resin film thinner than the first resin film, and the laminate is heated and press-molded to form a substrate layer from the substrate, a first resin film layer having openings in areas of the secondary resin film corresponding to the plurality of main openings is formed from the first resin film, and a breathable second resin film layer is formed from the second resin film. [Effects of the Invention]

[0008] According to the present invention, a lightweight vehicle undercover having good durability against contact with foreign objects and good sound absorption properties can be provided at low cost. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view schematically showing an example of an automobile having an undercover. [Figure 2] FIG. 1 is a bottom view schematically illustrating an example of a vehicle having an undercover. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an example of a vertical cross section of the undercover. [Figure 4] FIG. 2 is a cross-sectional view schematically showing an example of a vertical cross section of a substrate. [Figure 5] FIG. 2 is a cross-sectional view schematically showing an example of a vertical cross section of an undercover having a main resin film layer between a base material layer and a secondary resin film layer. [Figure 6] FIG. 2 is a cross-sectional view schematically showing an example of a vertical cross section of an undercover having a secondary resin film layer between a base material layer and a primary resin film layer. [Figure 7] FIG. 4 is a bottom view illustrating a schematic example of a main part of the road-facing surface of the undercover. [Figure 8] 5A to 5C are diagrams schematically showing an example of a manufacturing method for the undercover. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention. Of course, the following embodiments are merely examples of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution of the invention.

[0011] (1) Overview of the technology included in this invention: First, an overview of the technology included in the present invention will be described with reference to the examples shown in Figures 1 to 8. Note that the figures in this application are diagrams showing schematic examples, and the magnifications in the directions shown in these figures may differ, and the figures may not be consistent. Of course, each element of the present technology is not limited to the specific example indicated by the symbol. In addition, in the present application, a numerical range "Min to Max" means a value equal to or greater than the minimum value Min and equal to or less than the maximum value Max.

[0012] [Aspect 1] A vehicle undercover 1 according to one aspect of the present technology is an integrally molded vehicle undercover 1 and includes a base material layer 10, a first resin film layer 20, and a second resin film layer 30. The base material layer 10 includes inorganic fibers 11 and a solidified thermoplastic binder 12. The first resin film layer 20 is integrated with a surface 13a of the base material layer 10 facing the road surface. The second resin film layer 30 is breathable and is integrated with a surface 13b of the base material layer 10 facing the vehicle body. The first resin film layer 20 is thicker than the second resin film layer 30 and has a plurality of openings 21 that allow air to circulate in a thickness direction D1. The vehicle undercover 1 is breathable.

[0013] In the above embodiment, the first resin film layer 20 on the road surface side is thicker than the second resin film layer 30 on the vehicle body side, thereby providing good durability against contact with foreign objects such as stones. Furthermore, the first resin film layer 20 on the road surface side has a plurality of openings 21 that allow air to circulate in the thickness direction D1, providing good breathability. This provides good sound absorption. Furthermore, since the layer integrated with the road surface side surface 13a of the base material layer 10 is only a resin film layer, the vehicle undercover 1 can be lightweight and inexpensive. Therefore, the above embodiment can provide a lightweight vehicle undercover that has good durability against contact with foreign objects and good sound absorption at low cost.

[0014] Here, inorganic fibers include glass fibers, carbon fibers, silicon carbide fibers, alumina fibers, ceramic fibers, rock fibers, slag fibers, and the like. The thermoplastic binder may be fibrous or non-fibrous. The substrate layer may contain materials other than inorganic fibers and a thermoplastic binder. The substrate layer may be a needle-punched layer or may include multiple layers. At least a portion of the first resin film layer integrated with the road surface side of the base layer may be impregnated into the road surface side of the base layer. The first resin film layer may include a plurality of layers. At least a portion of the second resin film layer integrated with the surface of the base material layer facing the vehicle body may be impregnated into the surface of the base material layer facing the vehicle body. The second resin film layer may include a plurality of layers. The second resin film layer having breathability means that air can flow from one side to the other side of the second resin film layer. The vehicle undercover having breathability means that air can flow from one side to the other side of the vehicle undercover. The vehicle undercover may have other layers than those described above, such as an extremely thin breathable fiber layer. The above remarks also apply to the following aspects.

[0015] [Aspect 2] 5 to 7, the first resin film layer 20 may include a main resin film layer 22 having a plurality of main openings 23. The first resin film layer 20 may include a secondary resin film layer 24 that is thinner than the main resin film layer 22 and has a plurality of secondary openings 25. The plurality of main openings 23 and the plurality of secondary openings 25 may form the plurality of openings 21. The secondary resin film layer 24 may be present in a part of the region of the road-side surface 13a of the base material layer 10 that corresponds to the plurality of main openings 23 so as to have breathability. In the above case, the secondary resin film layer 24 is present in a breathable manner in a part of the main opening corresponding area A1 of the road surface side surface 13a of the base material layer 10 that corresponds to the plurality of main openings 23 of the primary resin film layer 22, thereby reducing the exposed portion of the road surface side surface 13a of the base material layer 10. Therefore, the above embodiment can improve ice accretion resistance.

[0016] [Aspect 3] The MFR of the main resin film layer 22 may be 0.1 to 10 g / 10 min. The MFR of the secondary resin film layer 24 may be 0.5 to 30 g / 10 min, which is greater than the MFR of the main resin film layer 22. Here, MFR is the melt mass-flow rate specified in JIS K7210-1:2014 (Plastics - Determination of melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics - Part 1: Standard test method). In the above cases, the MFR of the main resin film layer 22, which is thicker than the secondary resin film layer 24, is relatively small, thereby suppressing collapse of the main opening 23 in the main resin film layer 22. Furthermore, the MFR of the secondary resin film layer 24, which is thinner than the main resin film layer 22, is relatively large, thereby suppressing blockage of the main opening 23 by the secondary resin film layer 24. Therefore, the above embodiment can provide a suitable example for improving ice accretion resistance.

[0017] [Aspect 4] 5 and 6, the second resin film layer 30 may be thicker than the secondary resin film layer 24 and may have a plurality of openings 31 for allowing air to circulate in the thickness direction D1. The MFR of the second resin film layer 30 may be smaller than the MFR of the secondary resin film layer 24. In the above cases, the MFR of the second resin film layer 30, which is thicker than the secondary resin film layer 24, is relatively small, thereby suppressing crushing of the openings 31 in the second resin film layer 30. Therefore, the above embodiment can provide a suitable example of a vehicle undercover with good sound absorption properties.

[0018] [Aspect 5] The secondary resin film layer 24 may contain a colorant. In the above cases, the base material layer 10 is difficult to see through the plurality of openings 21 of the first resin film layer 20. Therefore, the above embodiment can improve the appearance of the vehicle undercover.

[0019] [Aspect 6] 8 , a manufacturing method of a vehicle undercover 1 according to one embodiment of the present technology manufactures the vehicle undercover 1 from a laminated material 50 in which a first resin film 70 including a thermoplastic main resin film 72 having a plurality of main openings 73 and a thermoplastic secondary resin film 74 thinner than the main resin film 72, a substrate 60 including inorganic fibers 11 and a thermoplastic binder 12, and a thermoplastic second resin film 80 thinner than the first resin film 70 are stacked in this order. In this manufacturing method, the laminated material 50 is heated and press-molded to form a substrate layer 10 from the substrate 60, the first resin film layer 20 in which regions of the secondary resin film 74 corresponding to the plurality of main openings 73 (e.g., main opening corresponding regions A1) are partially opened is formed from the first resin film 70, and the breathable second resin film layer 30 is formed from the second resin film 80.

[0020] In the above embodiment, the first resin film layer 20 is formed from the first resin film 70, in which a portion of an area (A1) of the secondary resin film 74 corresponding to the plurality of main openings 73 of the primary resin film 72 is opened to provide breathability upon heating. The secondary resin film 74 is present in a breathable manner in a portion of the main opening corresponding area A1 of the road surface side surface 13a of the base material layer 10 that corresponds to the plurality of main openings 73 of the primary resin film 72, thereby reducing the exposed portion of the road surface side surface 13a of the base material layer 10 (for example, the base material layer exposed area A3). Therefore, the above embodiment can improve the icing resistance of a lightweight vehicle undercover 1 that has good durability against contact with foreign objects and good sound absorption properties at low cost.

[0021] (2) Specific examples of the configuration of a vehicle having a vehicle undercover: 1 and 2 are schematic diagrams illustrating an example of an automobile having an undercover. The automobile 100 shown in FIGS. 1 and 2 is a road vehicle designed and equipped for use on roads, and is a passenger automobile having a cabin CA1 surrounded by a vehicle body 101. In these drawings, FRONT, REAR, LEFT, RIGHT, UP, and DOWN indicate the front, rear, left, right, top, and bottom, respectively. The left-right positional relationship is based on the direction looking forward while sitting in the driver's seat in the cabin CA1. In the automobile 100 shown in FIG. 1, a front tire 111 and a rear tire 112 are in contact with a road surface 200.

[0022] A vehicle undercover 1 is attached under the vehicle body 101 so as not to come into contact with the road surface 200. The undercover 1 has the functions of reducing the air resistance that occurs under the vehicle body 101 when the vehicle is traveling (improving fuel efficiency), protecting the vehicle body 101 from foreign objects such as stones that are kicked up when the vehicle is traveling, and sound absorbing and sound insulating functions that improve the quietness of the vehicle interior CA1.

[0023] The undercover 1 shown in FIG. 2 is divided into multiple undercovers 1a, 1b, 1c, 1c, 1d, and 1d. The engine undercover 1a is disposed under the engine of the automobile 100 between the left and right front tires 111, 111. The mission cover 1b is disposed under the transmission of the automobile 100 rearward of the engine undercover 1a. The left and right front floor undercovers 1c, 1c are disposed under the floor panel of the automobile 100 rearward of the front tire 111, 111. The left and right rear floor undercovers 1d, 1d are disposed under the floor panel of the automobile 100 forward of the rear tire 112, 112 and rearward of the front floor undercover 1c, 1c.

[0024] Fig. 3 shows a schematic vertical cross section of the undercover 1. Fig. 4 shows a schematic vertical cross section of a substrate 60 for forming the substrate layer 10. The cross sections of the examples shown in Figs. 3 and 4 are exaggerated for clarity. Reference symbol D1 shown in Figs. 3 and 4 indicates the thickness direction of the undercover 1, the thickness direction of each layer 10, 20, 30, and the thickness direction of the substrate 60.

[0025] The press-molded base layer 10 contains inorganic fibers 11 and a solidified thermoplastic binder 12. In FIG. 3, the inorganic fibers 11 are shown by thin lines, and the solidified thermoplastic binder 12 is located around the inorganic fibers 11. The base layer 10 is breathable, allowing air to circulate in the thickness direction D1. Note that breathability refers to a permeability of 0.05 cc / cm. 2 / sec or more (more preferably 1cc / cm 2 / sec or more, more preferably 3cc / cm 2 / sec or more). Here, the air permeability is determined according to Method A (Fragile method) specified in JIS L1096:2010 (Testing methods for woven and knitted fabrics). The base material layer 10, which contains air between the inorganic fibers 11 and the thermoplastic binder 12, exhibits sound absorbing properties.

[0026] A first resin film layer 20 having a plurality of openings 21 that allow air to circulate in the thickness direction D1 is formed on the road-side surface 2a of the integrally press-molded undercover 1. The first resin film layer 20 is integrated with the road-side surface 13a of the base layer 10. Part or all of the first resin film layer 20 may be impregnated into the road-side surface 13a of the base layer 10. This provides good chipping resistance (resistance to peeling) for the first resin film layer 20. In many cases, the road-side surface 2a of the undercover 1 is formed with unevenness. The first resin film layer 20 has breathability due to the plurality of openings 21, allowing air to circulate in the thickness direction D1. Sound that passes through the first resin film layer 20 from the road-side surface 2a is absorbed by the base layer 10. Furthermore, the presence of the first resin film layer 20 on the road-side surface 2a of the undercover 1 provides good durability against contact with foreign objects such as stones.

[0027] A second resin film layer 30 having a plurality of openings 31 that allow air to circulate in the thickness direction D1 is formed on the vehicle body 101-side surface 2b of the integrally press-molded undercover 1. The second resin film layer 30 is integrated with the vehicle body-side surface 13b of the base layer 10. Part or all of the second resin film layer 30 may be impregnated into the vehicle body-side surface 13b of the base layer 10. This provides good chipping resistance for the second resin film layer 30. In many cases, the vehicle body-side surface 2b of the undercover 1 is formed with unevenness. The second resin film layer 30 has breathability due to the plurality of openings 31, allowing air to circulate in the thickness direction D1. Sound that passes through the second resin film layer 30 from the vehicle body-side surface 2b is absorbed by the base layer 10. Furthermore, the presence of the second resin film layer 30 on the vehicle body-side surface 2b of the undercover 1 provides good durability for the vehicle body-side surface 2b of the undercover 1 despite its light weight.

[0028] Each of the layers 10, 20, and 30 will be described in detail below. The inorganic fibers 11 of the substrate layer 10 are fibers primarily containing inorganic substances and are a material that does not melt even when the substrate 60 for forming the substrate layer 10 is heated, thereby maintaining a fibrous state. Therefore, the inorganic fibers 11 of the substrate 60 remain after press molding. Examples of inorganic fibers that can be used include glass fibers, carbon fibers, silicon carbide fibers, alumina fibers, ceramic fibers, rock fibers, and slag fibers, with relatively inexpensive glass fibers being particularly preferred. The diameter of the inorganic fibers is not particularly limited, but can be, for example, 5 to 14 μm. The length of the inorganic fibers is not particularly limited, but can be, for example, 5 to 200 mm. The cross-sectional shape of the inorganic fibers is not particularly limited, and can be, for example, an ellipse including a perfect circle, a triangle, or a flattened shape. A combination of multiple types of inorganic fibers may be used as the inorganic fibers 11.

[0029] The thermoplastic binder 12 of the base layer 10 is a binder primarily containing a thermoplastic adhesive component such as a thermoplastic resin. It softens when the base 60 is heated and melts when further heated. When melted, the thermoplastic binder 12 bonds the inorganic fibers 11 together, bonds the base layer 10 to the first resin film layer 20, and bonds the base layer 10 to the second resin film layer 30. Examples of thermoplastic resins (including thermoplastic elastomers) for the thermoplastic binder include polyolefin resins such as PP (polypropylene) resin and PE (polyethylene) resin, modified resins obtained by adding elastomers to these synthetic resins, and materials obtained by adding additives such as colorants to these synthetic resins. PP resin, which is relatively inexpensive, is particularly preferred. A combination of multiple types of thermoplastic binders may be used for the thermoplastic binder 12.

[0030] The thermoplastic binder 12 of the substrate 60 for forming the substrate layer 10 may be a thermoplastic adhesive fiber such as a thermoplastic resin fiber. Therefore, the fibrous thermoplastic binder 12 of the substrate 60 may lose its fibrous form after press molding due to melting. The adhesive fiber may be the above-mentioned thermoplastic resin fiber (e.g., polyolefin fiber such as PP (polypropylene) fiber or PE (polyethylene) fiber), or a fiber having a conjugate structure such as a core-sheath structure or a side-by-side structure, or a combination of multiple types of adhesive fibers. The melting point of the adhesive fiber may be, for example, 100 to 220°C. The fineness of the adhesive fiber is not particularly limited, but may be, for example, 2.2 to 16 dtex (decitex). Here, the unit "dtex" means the number of grams of mass per 10 km of length. The length of the adhesive fiber is not particularly limited, but may be, for example, 27 to 76 mm. The cross-sectional shape of the adhesive fiber is not particularly limited, and may be elliptical (including perfect circle), triangular, flat, etc. The base material 60 is breathable, and therefore allows air to circulate in the thickness direction D1. The present technology also includes a case where the thermoplastic binder 12 of the substrate 60 is not a fiber.

[0031] The compounding ratio (referred to as R1) of the inorganic fibers 11 to the substrate 60 (i.e., the substrate layer 10) can be, for example, 10 to 90% by weight. The compounding ratio (referred to as R2) of the thermoplastic binder 12 to the substrate 60 can be, for example, 10 to 90% by weight, provided that R1+R2≦100% by weight. Other materials (e.g., fibers) may be added to the substrate 60 at a compounding ratio in the range of R1+R2 or less (preferably in the range where R1+R2≧75% by weight).

[0032] The weight per unit area of the substrate 60 (i.e., the substrate layer 10) is 500 to 3000 g / m 2 The weight of the substrate 60 is preferably about 3000 g / m 2 When the weight per unit area of the base material 60 is 500 g / m or less, the weight of the undercover 1 can be reduced. 2 In this way, an undercover 1 having favorable durability against contact with foreign matter can be manufactured. The substrate 60 may be a needle-punched material. In this case, for example, the substrate 60 can be formed by mixing a fibrous material containing inorganic fibers 11 and a fibrous thermoplastic binder 12, arranging the mixture in a mat shape, and needle-punching the mixture with a needle-punching machine. The substrate 60 may also be a material in which multiple needle-punched fibrous materials are layered, as shown in JP 2018-69813 A.

[0033] The air permeability of the base layer 10 is 3 to 200 cc / cm 2 The air permeability of the base layer 10 is preferably about 3 cc / cm 2 When the air permeability of the base material layer 10 is 200 cc / cm or more, the air permeability of the undercover 1 is increased, and better sound absorption properties can be obtained for noise of about 500 to 2000 Hz. 2 / sec or less, the peak frequency of the sound absorption characteristics of the undercover 1 becomes lower, and therefore even better sound absorption properties can be obtained for noise of about 500 to 2000 Hz.

[0034] The breathability of the base layer 10 can be adjusted, for example, as follows. To increase the breathability of the base layer 10, the compounding ratio R2 of the thermoplastic binder 12 to the substrate 60 may be decreased, or the basis weight of the substrate 60 may be decreased. To decrease the breathability of the base layer 10, the compounding ratio R2 of the thermoplastic binder 12 to the substrate 60 may be increased, or the basis weight of the substrate 60 may be increased.

[0035] The first resin film layer 20 is a film-like layer formed from a first resin film 70 (see FIG. 8 ), and the second resin film layer 30 is a layer formed from a second resin film 80 (see FIG. 8 ). The resin films 70, 80 can be made of a material containing at least a synthetic resin such as a thermoplastic resin. Examples of thermoplastic resins (including thermoplastic elastomers) for the resin films 70, 80 include polyolefin resins such as PE resin and PP resin, ethylene vinyl acetate resin, modified resins obtained by adding elastomers to these resins, and materials obtained by adding additives such as colorants to these resins. Low-fluidity polyolefin resins such as linear low-density polyethylene (LLDPE) are particularly suitable. When the low-fluidity resin films 70, 80 have multiple openings, the multiple openings remain even when the resin films 70, 80 melt and partially or completely impregnate the base layer 10. This facilitates the formation of a first resin film layer 20 having multiple openings 21, and a second resin film layer 30 having multiple openings 31. Furthermore, multiple openings 21 may be formed when the first resin film 70 superimposed on the substrate 60 melts, or multiple openings 31 may be formed when the second resin film 80 superimposed on the substrate 60 melts.

[0036] When the resin film layers 20, 30 (resin films 70, 80) exhibit thermoplasticity, the MFR of the resin film layers 20, 30 (resin films 70, 80) can be, for example, about 0.1 to 30 g / 10 min, more preferably about 0.3 to 20 g / 10 min.

[0037] The thickness of the first resin film 70 is preferably 50 to 350 μm, more preferably 100 to 300 μm, thicker than the second resin film 80. Because the first resin film layer 20 may be impregnated into the base material layer 10, the thickness T1 of the first resin film layer 20 is preferably 50 to 700 μm, more preferably 100 to 600 μm, thicker than the second resin film layer 30. Here, when the resin film layers 20, 30 are impregnated into the base material layer 10, the thicknesses T1, T2 of the resin film layers 20, 30 refer to the thicknesses of the resin film layers 20, 30 in a state where they have impregnated into the base material layer 10. The thicknesses T1, T2 are the arithmetic mean values of the thicknesses of the resin film layers 20, 30 measured at multiple locations (e.g., 10 locations) by observing the cross section of the undercover 1 under a microscope. When the thickness T1 of the first resin film layer 20 is 700 μm or less, the weight of the undercover 1 can be reduced. When the thickness T1 of the first resin film layer 20 is 50 μm or more, the air permeability of the undercover 1 is reduced to a certain extent, and therefore better sound absorption properties against noise can be obtained.

[0038] The thickness of the second resin film 80 is preferably 10 to 200 μm, more preferably 30 to 100 μm, in the range thinner than that of the first resin film 70. Because the second resin film layer 30 may be impregnated into the base material layer 10, the thickness T2 of the second resin film layer 30 is preferably 10 to 400 μm, more preferably 30 to 200 μm, in the range thinner than that of the first resin film layer 20. When the thickness T2 of the second resin film layer 30 is 400 μm or less, the weight of the undercover 1 can be reduced. When the thickness T2 of the second resin film layer 30 is 10 μm or more, the breathability of the undercover 1 is reduced to a certain extent, thereby achieving even better sound absorption properties against noise.

[0039] The basis weight of the first resin film layer 20 (first resin film 70) is in the range of 50 to 350 g / m 2 , which is larger than the basis weight of the second resin film layer 30 (second resin film 80). 2 is preferable, and 100 to 300 g / m 2 It is more preferable that the basis weight of the first resin film layer 20 is 350 g / m 2When the basis weight of the first resin film layer 20 is 50 g / m or less, the weight of the undercover 1 can be reduced. 2 If this is the case, the air permeability of the undercover 1 is reduced to a certain extent, and therefore even better sound absorption properties against noise can be obtained.

[0040] The basis weight of the second resin film layer 30 (second resin film 80) is in the range of 10 to 200 g / m 2 , which is smaller than the basis weight of the first resin film layer 20 (first resin film 70). 2 is preferable, and 30 to 100 g / m 2 It is more preferable that the basis weight of the second resin film layer 30 is 200 g / m 2 When the basis weight of the second resin film layer 30 is 10 g / m or less, the weight of the undercover 1 can be preferably reduced. 2 If this is the case, the air permeability of the undercover 1 is reduced to a certain extent, and therefore even better sound absorption properties against noise can be obtained.

[0041] The resin film layers 20 and 30 have an air permeability of 0.1 to 200 cc / cm 2 The resin film layers 20 and 30 preferably have an air permeability of 0.1 cc / cm 2 When the air permeability of the resin film layers 20, 30 is 200 cc / cm or more, the air permeability of the undercover 1 is increased, thereby achieving better sound absorption properties for noise of about 500 to 2000 Hz. 2 / sec or less, the peak frequency of the sound absorption characteristics of the undercover 1 becomes lower, and therefore even better sound absorption properties can be obtained for noise of about 500 to 2000 Hz.

[0042] The breathability of the thermoplastic resin film layers 20, 30 can be adjusted, for example, as follows. In order to increase the breathability of the resin film layers 20, 30, the MFR of the resin film layers 20, 30 may be increased or the basis weight of the resin films 70, 80 may be reduced. This makes it easier for the openings 21, 31 in the resin film layers 20, 30 to become larger after press molding, thereby increasing the breathability of the resin film layers 20, 30. In order to decrease the breathability of the resin film layers 20, 30, the MFR of the resin film layers 20, 30 may be decreased or the basis weight of the resin films 70, 80 may be increased. This makes it easier for the openings 21, 31 in the resin film layers 20, 30 to become smaller after press molding, thereby decreasing the breathability of the resin film layers 20, 30.

[0043] The press-molded undercover 1 can have a thickness of, for example, 1 to 17 mm. The thickness T0 of the general portion of the undercover 1 can be, for example, 3 to 17 mm. The density of the press-molded undercover 1 is, for example, 0.05 to 0.5 g / cm 3 , more preferably 0.1 to 0.3 g / cm 3 It can be said that:

[0044] The basis weight of the undercover 1 is 560~3550g / m 2 It is preferable that the basis weight of the undercover 1 is 560 g / m 2 When the weight per unit area is 3550 g / m or more, an undercover 1 having preferable durability against contact with foreign matter can be obtained. 2 Thus, an undercover 1 having good durability can be obtained while being lightweight at less than 100 mm.

[0045] The undercover 1 is breathable due to the breathability of the base material layer 10 and the resin film layers 20, 30. The breathability of the undercover 1 is 0.05 to 70 cc / cm 2 / sec is preferred, and 1 to 50cc / cm 2 / sec is more preferable, and 2 to 30cc / cm 2 / sec is more preferable, and 3 to 15cc / cm2 / sec is particularly preferable. 2 / sec or more, even better sound absorption is achieved for noises of about 500 to 2000 Hz. 2 / sec or less, the peak frequency of the sound absorption characteristics of the undercover 1 becomes lower, and therefore even better sound absorption properties can be obtained for noise of about 500 to 2000 Hz.

[0046] The press-molded undercover 1 may have a general portion as well as a partially thinned thickness-reduced portion. The thickness-reduced portion is set in a position on the undercover 1 that is likely to be pinched between a vehicle component and an obstacle, such as an end portion or a fastening portion to a vehicle component, when the vehicle runs over an obstacle such as a curb. The thickness of the thickness-reduced portion is thinner than the thickness of the general portion, and can be, for example, 1 to 3 mm.

[0047] As illustrated in Figures 5 and 6, the first resin film layer 20 may include a main resin film layer 22 and a secondary resin film layer 24. Figure 5 schematically illustrates a vertical cross section of an undercover 1A having the main resin film layer 22 between the base material layer 10 and the secondary resin film layer 24. Figure 6 schematically illustrates a vertical cross section of an undercover 1B having the secondary resin film layer 24 between the base material layer 10 and the main resin film layer 22. The concepts of the undercovers 1A and 1B are included in the concept of the undercover 1. The main resin film layer 22 is a film-like layer formed from the main resin film 72, and the secondary resin film layer 24 is a film-like layer formed from the secondary resin film 74.

[0048] 5 and 6 is thicker than the secondary resin film layer 24 and has a plurality of primary openings 23. The secondary resin film layer 24 is thinner than the primary resin film layer 22 and has a plurality of secondary openings 25. The primary openings 23 and the secondary openings 25 constitute the plurality of openings 21 of the first resin film layer 20.

[0049] FIG. 7 shows a schematic example of a main part of the road-side surface 2a of the undercover 1A. As shown in FIGS. 5 to 7 , the secondary resin film layer 24 is present in a breathable portion of a main opening corresponding region A1 on the road surface-facing surface 13a of the base material layer 10, corresponding to the multiple main openings 23. For convenience of illustration in FIG. 5 , the secondary resin film layer 24 is depicted as being separated from the base material layer 10 in the main opening corresponding region A1. However, the press-molded secondary resin film layer 24 is integrated with the road surface-facing surface 13a of the base material layer 10 in the main opening corresponding region A1. The main opening corresponding region A1 includes a secondary resin presence region A2 where the secondary resin film layer 24 is present and a base material layer exposed region A3 where the base material layer 10 is exposed. Because FIG. 7 shows the regions A1 to A3 schematically, the regions A1 to A3 do not necessarily have the shapes shown in FIG. 7 . The main opening corresponding region A1 is not limited to a circular shape; multiple base material layer exposed regions A3 may be present in the main opening corresponding region A1, or a secondary resin presence region A2 independent of the surroundings may be present in the main opening corresponding region A1. The road-side surface 2a of the undercover 1B appears the same as the road-side surface 2a of the undercover 1A, except that the main resin film layer 22 is visible except in the main opening corresponding region A1.

[0050] The main resin film 72 and the secondary resin film 74 can be made of thermoplastic resin films. However, the secondary resin film 74 is thinner than the main resin film 72 and has a higher MFR than the main resin film 72. As a result, the secondary resin film 74 melts when heated and partially opens in the main opening corresponding area A1, forming a secondary resin film layer 24 that exists in part of the main opening corresponding area A1 and has breathability. This reduces the exposed portion of the road surface side surface 13a of the base material layer 10, improving ice resistance. Furthermore, if the secondary resin film 74 contains a colorant, the secondary resin film layer 24 present in part of the main opening corresponding area A1 makes it difficult to see the base material layer 10 through the multiple openings 21 in the first resin film layer 20. Therefore, when the secondary resin film layer 24 contains a colorant, the appearance of the undercover 1 is improved.

[0051] The MFR of the thermoplastic main resin film layer 22 (main resin film 72) is smaller than the MFR of the secondary resin film layer 24 (secondary resin film 74), and is preferably 0.1 to 10 g / 10 min, and more preferably 0.3 to 5 g / 10 min. This causes the main resin film 72 to exhibit low fluidity when heated, and the multiple main openings provided in the main resin film 72 are not blocked by the main resin film 72 when heated, so that main openings 23 are formed in the main resin film layer 22. The MFR of the thermoplastic secondary resin film layer 24 (secondary resin film 74) is greater than the MFR of the primary resin film layer 22 (main resin film 72), and is preferably 0.5 to 30 g / 10 min, and more preferably 0.6 to 20 g / 10 min. Because the secondary resin film 74 exhibits higher fluidity than the primary resin film 72 when heated, the molten secondary resin film 74 partially opens in the main opening corresponding region A1, forming the secondary resin film layer 24 having a plurality of secondary openings 25 smaller than the main openings 23. It is preferable that the second resin film layer 30 (second resin film 80) on the vehicle body side has a higher MFR than the secondary resin film layer 24 (second resin film 74). This causes the second resin film 80 to exhibit low fluidity when heated, and the multiple openings provided in the second resin film 80 are not blocked by the second resin film 80 when heated, so that openings 31 are formed in the second resin film layer 30.

[0052] The thickness of the main resin film 72 is preferably in the range of 50 to 250 μm, more preferably 100 to 200 μm, which is thicker than the second resin film 80 and the sub-resin film 74. Since the main resin film layer 22 may impregnate the base material layer 10, the thickness T3 of the main resin film layer 22 is preferably in the range of 50 to 500 μm, more preferably 100 to 400 μm, which is thicker than the second resin film layer 30 and the sub-resin film layer 24. Here, the thicknesses T3 and T4 of the resin film layers 22 and 24 are the thicknesses of the resin film layers 22 and 24 in the state of impregnating the base material layer 10 when the resin film layers 22 and 24 impregnate the base material layer 10. The thicknesses T3 and T4 are the arithmetic mean values of the measured values when the cross-section of the under-cover 1 is observed with a microscope and the thicknesses of the resin film layers 22 and 24 are measured at a plurality of locations (for example, 10 locations). In the examples shown in FIGS. 5 and 6, the thickness T1 of the first resin film 70 is T3 + T4, and T4 < T2 < T3. When the thickness T3 of the main resin film layer 22 is 500 μm or less, the under-cover 1 can be preferably lightened. When the thickness T3 of the main resin film layer 22 is 50 μm or more, the air permeability of the under-cover 1 is suppressed to a certain extent, so that better sound absorption performance against noise can be obtained.

[0053] The thickness of the sub-resin film 74 is preferably in the range of 5 to 100 μm, more preferably 10 to 50 μm, which is thinner than the main resin film 72. Since the sub-resin film layer 24 may impregnate the base material layer 10, the thickness T4 of the sub-resin film layer 24 is preferably in the range of 5 to 200 μm, more preferably 10 to 100 μm, which is thinner than the main resin film layer 22. When the thickness T4 of the sub-resin film layer 24 is 200 μm or less, a plurality of suitable sub-openings 25 are formed in the sub-resin film layer 24.

[0054] The basis weight of the main resin film layer 22 (main resin film 72) is preferably in the range of 50 to 250 g / m 2 which is larger than the basis weights of the second resin film layer 30 and the sub-resin film layer 24, and more preferably 100 to 200 g / m 2 When the basis weight of the main resin film layer 22 is 250 g / m 2When the weight of the main resin film layer 22 is 50 g / m or less, the weight of the undercover 1 can be reduced. 2 If this is the case, the air permeability of the undercover 1 is reduced to a certain extent, and therefore even better sound absorption properties against noise can be obtained.

[0055] The weight of the secondary resin film layer 24 (secondary resin film 74) is in the range of 5 to 100 g / m 2 , which is smaller than the weight of the primary resin film layer 22 (primary resin film 72) 2 is preferable, and 10 to 50 g / m 2 It is more preferable that the weight of the secondary resin film layer 24 is 100 g / m 2 In the following manner, a suitable plurality of secondary openings 25 are formed in the secondary resin film layer 24.

[0056] (3) Specific examples of manufacturing methods for vehicle undercovers, and their actions and effects: Next, an example of a method for manufacturing the undercover 1 will be described with reference to FIG. 8 and other figures. FIG. 8 shows a specific example of manufacturing the undercover 1. In the manufacturing method shown in FIG. 8, a material laminating step S1 is first performed, in which a first resin film 70, a substrate 60, and a second resin film 80 are stacked in this order to form the layers 20, 10, and 30 shown in FIGS. 3, 5, and 6, thereby forming the laminate 50. As described above, the first resin film 70 is thicker than the second resin film 80. The first resin film 70 may be formed by extruding a molten or liquid synthetic resin into a film shape through a T-die (flat die) of an extrusion molding machine and then perforating multiple openings (corresponding to the openings 21) with a perforator. The first resin film 70 may also include a thermoplastic main resin film 72 having multiple main openings 73 and a thermoplastic secondary resin film 74 thinner than the main resin film 72. Note that if the main resin film 72 is located between the secondary resin film 74 and the substrate 60 as shown in FIG. 8, an undercover 1A such as that shown in FIG. 5 is formed. When the secondary resin film 74 is located between the primary resin film 72 and the substrate 60, an undercover 1B as shown in FIG. 6 is formed. The primary resin film 72 may be formed by extruding a molten resin into a film shape from a T-die of an extruder and punching a plurality of primary openings 73 with a perforator. The secondary resin film 74 may be formed by extruding a molten resin into a film shape from a T-die of an extruder. The substrate 60 may be formed by carding a fibrous material containing inorganic fibers 11 and a fibrous thermoplastic binder 12 into a mat shape and needle-punching it with a needle-punch processing machine. The second resin film 80 may be formed by extruding a molten resin into a film shape from a T-die of an extruder and punching a plurality of openings 81 with a perforator.

[0057] In this example, the laminate 50 obtained in the material lamination step S1 is heated to above the melting point of the thermoplastic binder 12 and the resin films 70, 80 in a preheating device and pressed in the thickness direction D1 in a prepressing device in a prepressing step S2. This melts at least a portion of the thermoplastic binder 12 and the resin films 70, 80, bonding the materials 70, 60, 80 together, unifying the laminate 50 for easier handling. Furthermore, the secondary resin film 74 may be partially opened in areas corresponding to the multiple main openings 73 in the primary resin film 72, forming multiple secondary openings 75 to provide breathability to the secondary resin film 74. Furthermore, at least a portion of the second resin film 80 may be impregnated into the surface of the substrate 60, forming multiple openings 81. Therefore, a second resin film 80 without openings 81 may be laminated on the substrate 60 in the material lamination step S1. When the integrated laminated material 50 reaches a temperature lower than the softening temperature of the thermoplastic binder 12 and the resin films 70, 80, the thermoplastic binder 12 and the resin films 70, 80 solidify, and the laminated material 50 remains integrated.

[0058] Thereafter, a laminate material heating step S3 is performed in which the integrated laminate material 50 is heated in a heating device to a temperature equal to or higher than the melting points of the thermoplastic binder 12 and the resin films 70, 80. As a result, at least a portion of the thermoplastic binder 12 and the resin films 70, 80 melt, and the base material 60 expands in the thickness direction D1 due to the restoring force of the inorganic fibers 11 of the base material 60, which had been compressed in the thickness direction D1. Furthermore, a portion of the secondary resin film 74 in an area corresponding to the multiple primary openings 73 of the primary resin film 72 may be opened, thereby forming multiple secondary openings 75 in the secondary resin film 74 to provide breathability. Furthermore, at least a portion of the second resin film 80 may impregnate the surface of the base material 60, thereby forming multiple openings 81. The heating in the preliminary pressing step S2 and the laminate material heating step S3 can be performed by radiant heating using an infrared heater, hot air heating using a suction heater (hot air circulation heater), contact heating using a hot press, or a combination of these.

[0059] After the laminate material heating step S3, a press-molding step S4 is performed in which the heated laminate 50 is press-molded using a press-molding device 300. The press-molding device 300 has a mold 310 that forms the uneven surface 2a of the undercover 1 that faces the road surface, and a mold 320 that forms the uneven surface 2b of the undercover 1 that faces the vehicle body 101. In FIG. 8, mold 310 is the lower mold and mold 320 is the upper mold, but mold 310 may be the upper mold and mold 320 may be the lower mold. The press-molding may be cold pressing or hot pressing. When the undercover 1 reaches a temperature lower than the softening temperatures of the thermoplastic binder 12 and the resin films 70, 80, the thermoplastic binder 12 and the resin films 70, 80 solidify, and the shape of the undercover 1 is maintained. By press molding, a base material layer 10 is formed from the substrate 60, a first resin film layer 20 having a portion of an opening in a main opening corresponding area A1 (see Figure 7) corresponding to the multiple main openings 73 of the secondary resin film 74 is formed from the first resin film 70, and a breathable second resin film layer 30 is formed from the second resin film 80.

[0060] If necessary, a cutting step S5 may be performed in which the outer periphery of the press-molded product is cut using a cutting machine. The cutting method may be cutting using a cutting blade, water jet cutting, manual cutting using a cutter, or the like. As described above, the undercover 1 having the layers 20, 10, and 30 as shown in FIGS. 3, 5, and 6 can be manufactured.

[0061] The undercover 1 of this example has good durability against contact with foreign objects such as stones because the first resin film layer 20 on the road surface side is thicker than the second resin film layer 30 on the vehicle body side. Furthermore, the first resin film layer 20 on the road surface side has a plurality of openings 21 that allow air to circulate in the thickness direction D1, making it breathable. This gives the undercover 1 good sound absorption properties. Furthermore, because the layer integrated with the road surface side surface 13a of the base material layer 10 is only a resin film layer, the undercover 1 can be lightweight and inexpensive. Therefore, this example can provide a lightweight vehicle undercover that has good durability against contact with foreign objects and good sound absorption properties at low cost.

[0062] When the first resin film 70 includes a main resin film 72 and a secondary resin film 74, a first resin film layer 20 is formed from the first resin film 70, in which a portion of a main opening corresponding region A1 of the secondary resin film 74 that corresponds to the plurality of main openings 73 of the primary resin film 72 is opened to have breathability upon heating. The presence of the secondary resin film 74 in a portion of the main opening corresponding region A1 on the road-side surface 13a of the base material layer 10 in a breathable manner reduces the exposed base material layer region A3 (see FIG. 7 ) on the road-side surface 13a of the base material layer 10. Therefore, the manufacturing method of this specific example can improve the ice accretion resistance of a lightweight vehicle undercover that has good durability against contact with foreign objects and good sound absorption properties at low cost.

[0063] Furthermore, even if the vehicle undercover 1 does not have the second resin film layer 30 on the vehicle body side, the secondary resin film 74 is present in part of the main opening corresponding area A1 so as to have breathability, thereby achieving the effect of improving the ice resistance of the vehicle undercover 1.

[0064] As described above, the vehicle undercover 1 of the present technology is an integrally molded vehicle undercover 1, a substrate layer 10 including inorganic fibers 11 and a solidified thermoplastic binder 12; a resin film layer having a plurality of openings 21 for allowing air to circulate in a thickness direction D1 and integrated with one surface (13a) of the base material layer 10; The resin film layer is a main resin film layer 22 having a plurality of main openings 23; a secondary resin film layer (24) that is thinner than the primary resin film layer (22) and has a plurality of secondary openings (25); the plurality of main openings 23 and the plurality of sub-openings 25 constitute the plurality of openings 21; The secondary resin film layer 24 has a configuration in which it is present in a part of the region (A1) on the one surface of the base material layer 10 that corresponds to the plurality of main openings 23 so as to have breathability. The above embodiment can improve the ice accretion resistance of the vehicle undercover 1.

[0065] In addition, a manufacturing method of a vehicle undercover 1 according to the present technology is a manufacturing method of a breathable vehicle undercover 1 including a base material layer 10 and a resin film layer (20) integrated with one surface (13a) of the base material layer 10, The present invention has an embodiment in which a base material layer 10 is formed from the base material 60 by heating and press-molding a laminated material 50 including a base material 60 containing inorganic fibers 11 and a thermoplastic binder 12, and a resin film (70) including a thermoplastic main resin film 72 having a plurality of main openings 73 and a thermoplastic secondary resin film 74 that is thinner than the main resin film 72, and the base material layer 10 is formed from the resin film (70), and the resin film layer (20) is formed from the resin film (70) in which a portion of the secondary resin film 74 in an area (A1) corresponding to the plurality of main openings 73 is opened. The above embodiment can improve the ice accretion resistance of the vehicle undercover 1.

[0066] The present invention will be specifically explained below by showing more detailed examples, but the present invention is not limited to the following examples.

[0067] [Example 1] The substrate 60 is a needle-punched fiber material (basis weight 525 g / m) containing glass fiber (an example of inorganic fiber 11) and PP fiber (an example of thermoplastic binder 12). 2 The main resin film 72 was a 150 μm thick (150 g / m2) fiber material made of LLDPE with an MFR of 0.64 g / 10 min. 2 The secondary resin film 74 was a 30 μm thick (30 g / m2) LLDPE film with main openings 73 of 1.5 mm diameter formed at intervals of 10 mm vertically and 10 mm horizontally. 2 ) black film without apertures was used. According to the manufacturing method shown in FIG. 8, a sample of the breathable undercover 1A shown in FIG. 5 was produced.

[0068] [Example 2] The substrate 60 and the main resin film 72 were the same as those in Example 1. The secondary resin film 74 was a 20 μm thick (basis weight 20 g / m) LLDPE film with an MFR of 0.68 g / 10 min containing a black colorant. 2 ) black film without apertures was used. According to the manufacturing method shown in FIG. 8, a sample of the breathable undercover 1A shown in FIG. 5 was produced.

[0069] [Example 3] The substrate 60, the main resin film 72, and the secondary resin film 74 were the same as those in Example 3. According to the manufacturing method shown in FIG. 8, a sample of the breathable undercover 1B as shown in FIG. 6 was produced.

[0070] [Example 4] The substrate 60 used was the same as in Examples 1 to 3. The first resin film 70 was a 150 μm thick (basis weight 150 g / m) LLDPE film containing a black colorant and having an MFR of 0.64 g / 10 min. 2 The film used was a black film with 1.5 mm diameter openings formed at intervals of 10 mm vertically and 10 mm horizontally. According to the manufacturing method shown in FIG. 8, a sample of the breathable undercover 1 shown in FIG. 3 was produced.

[0071] [Comparative Example 1] The substrate 60 used was the same as in Examples 1 to 4. Instead of the first resin film 70, a 200 g / m2 polyester fiber-based film containing PET (polyethylene terephthalate) fibers and PP fibers was used. 2 A breathable undercover sample was made using the nonwoven fabric.

[0072] [evaluation] The samples of Examples 1 to 4 are slightly lighter than the sample of Comparative Example 1. Furthermore, the samples of Examples 1 to 4 have almost the same performance in terms of durability against contact with foreign objects and sound absorption as the sample of Comparative Example 1. Since the layer integrated with the road-side surface 13a of the base material layer 10 can be a resin film layer, the vehicle undercover can be manufactured at low cost. Moreover, the samples of Examples 1 to 3 have good ice resistance.

[0073] (4) Variation: The present invention can be modified in various other ways. For example, when a plurality of fiber materials are layered as the substrate 60, at least one of the inorganic fibers 11 and the thermoplastic binder 12 may be different between one fiber material and another fiber material. In other words, when the substrate layer 10 includes a plurality of layers, at least one of the inorganic fibers 11 and the thermoplastic binder 12 may be different between one layer and another layer.

[0074] (5) Conclusion: As explained above, according to various aspects of the present invention, it is possible to provide a technology for providing a lightweight vehicle undercover at low cost that has good durability against contact with foreign objects and good sound absorption properties, a technology for improving the ice resistance of a vehicle undercover, etc. Of course, even a technology consisting only of the constituent elements according to the independent claims (including aspects described in the embodiments) can obtain the basic actions and effects described above. Furthermore, it is possible to implement configurations in which the components disclosed in the above examples are substituted with each other or the combination is changed, or configurations in which the components disclosed in the publicly known techniques and the above examples are substituted with each other or the combination is changed, etc. The present invention also includes these configurations. [Explanation of symbols]

[0075] 1,1A,1B...Undercover, 2a...road surface side, 2b...car body side surface, 10...base material layer, 11...inorganic fiber, 12...thermoplastic binder, 13a...road surface side, 13b...car body side surface, 20...first resin film layer, 21...opening, 22...main resin film layer, 23...main opening, 24...secondary resin film layer, 25...secondary opening, 30... second resin film layer, 31... opening, 50...Laminated material, 60...Base material, 70...first resin film, 72...main resin film, 73...main opening, 74...secondary resin film, 75...secondary opening, 80... second resin film, 81... opening, 100...Automobile, 101...Car body, 111, 112...Tire, 200...Road surface, 300...press molding device, 310, 320...mold, A1...Main opening corresponding area, A2...Sub-resin presence area, A3...Base material layer exposed area, CA1...cabin, D1...thickness direction.

Claims

1. An integrally molded vehicle undercover, a substrate layer including inorganic fibers and a solidified thermoplastic binder; a first resin film layer integrated with the road surface side surface of the base material layer; a second resin film layer that is breathable and integrated with the vehicle body side surface of the base material layer, the first resin film layer is thicker than the second resin film layer and has a plurality of openings that allow air to circulate in a thickness direction; A breathable vehicle undercover.

2. The first resin film layer is a main resin film layer having a plurality of main openings; a secondary resin film layer that is thinner than the primary resin film layer and has a plurality of secondary openings; the plurality of main openings and the plurality of sub-openings constitute the plurality of openings, The vehicle undercover according to claim 1 , wherein the secondary resin film layer is present in a breathable manner in a part of an area of the road-side surface of the base material layer that corresponds to the plurality of main openings.

3. the melt mass flow rate of the main resin film layer is 0.1 to 10 g / 10 min; 3. The vehicle undercover according to claim 2, wherein the melt mass flow rate of the secondary resin film layer is in the range of 0.5 to 30 g / 10 min, which is greater than the melt mass flow rate of the primary resin film layer.

4. the second resin film layer is thicker than the secondary resin film layer and has a plurality of openings that allow air to circulate in a thickness direction; The vehicle undercover according to claim 3 , wherein the second resin film layer has a melt mass-flow rate smaller than the melt mass-flow rate of the secondary resin film layer.

5. The vehicle undercover according to any one of claims 2 to 4, wherein the secondary resin film layer contains a colorant.

6. A method for manufacturing a breathable vehicle undercover, comprising: a base material layer; a first resin film layer integrated with a surface of the base material layer facing a road surface; and a second resin film layer integrated with a surface of the base material layer facing a vehicle body, A method for manufacturing a vehicle undercover, comprising: heating and press-molding a laminate obtained by stacking, in this order, a first resin film including a thermoplastic main resin film having a plurality of main openings and a thermoplastic secondary resin film thinner than the main resin film, a substrate including inorganic fibers and a thermoplastic binder, and a thermoplastic second resin film thinner than the first resin film; forming a substrate layer from the substrate; forming, from the first resin film, the first resin film layer, in which regions of the secondary resin film corresponding to the plurality of main openings are partially opened, and forming, from the second resin film, the second resin film layer, which is breathable.

Images