Molded ceiling material for vehicle and manufacturing method therefor

Abstract

A molded ceiling material 10 for a vehicle disposed on the vehicle cabin inner side of a roof panel 2 in a vehicle 1 includes a base material layer 20, a first fiber reinforcement layer 21, a second fiber reinforcement layer 22, a skin layer 30, and a rear surface layer 40. The rear surface layer 40 has an air-impermeable film layer 41 and a nonwoven fabric layer 45 in order from the vehicle cabin inner side, and the nonwoven fabric layer 45 contains aluminum.

Description

Molded vehicle ceiling material and its manufacturing method

[0001] Cross-reference to related applications This application is based on Japanese Patent Application No. 2024-147947 filed on August 29, 2024 and Japanese Patent Application No. 2025-060855 filed on April 1, 2025, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a molded vehicle ceiling material used in vehicles such as automobiles, and a method for manufacturing the same.

[0003] A commonly known molded vehicle ceiling material is one that uses a base layer made of hard urethane or the like, with glass fiber reinforcement layers on both sides of the base layer, and a surface layer and a backing layer on the outside of each glass fiber reinforcement layer (Patent Document 1).

[0004] Also known is a vehicle ceiling molding material that has, as its back surface layer, a non-breathable synthetic resin film and an aluminum vapor deposition film formed by vapor-depositing aluminum onto the surface of the non-breathable film (Patent Document 2).

[0005] JP 2009-90548 A JP 2014-91442 A

[0006] In some cases, vehicle components such as harnesses are bonded to the back surface of a vehicle molded ceiling material. However, if the back surface is provided with an aluminum vapor deposition film, as in the vehicle molded ceiling material of Patent Document 2, there is a concern that the vehicle components bonded to the aluminum vapor deposition film may easily peel off.

[0007] An object of the present invention is to provide a molded vehicle ceiling material that can suppress peeling of vehicle parts, and a method for manufacturing the same.

[0008] The invention of claim 1 is a panel-shaped molded ceiling material for vehicles arranged on the interior side of a roof panel in a vehicle, comprising a base material layer, a first fiber reinforcement layer provided on the interior side of the base material layer, a second fiber reinforcement layer provided on the roof panel side of the base material layer, a skin layer provided on the interior side of the first fiber reinforcement layer, and a back layer provided on the roof panel side of the second fiber reinforcement layer, wherein the back layer has, in order from the interior side of the vehicle, a non-air-permeable membrane layer and a nonwoven fabric layer, and the nonwoven fabric layer has aluminum attached to its surface.

[0009] The invention of claim 2 is characterized in that, in the vehicle ceiling material of claim 1, the aluminum is aluminum powder, and the aluminum powder is dispersed and adhered to the surface of the nonwoven fabric layer.

[0010] The invention of claim 3 is characterized in that in the vehicle ceiling material of claim 2, the aluminum powder is derived from aluminum powder contained in ink.

[0011] The invention of claim 4 is characterized in that, in the method for manufacturing a molded vehicle ceiling material of claim 2, one side of a nonwoven fabric sheet that forms the nonwoven fabric layer is joined to the non-air-permeable membrane layer to form a back surface layer, the ink containing aluminum powder is printed on the other side of the nonwoven fabric sheet, a skin material that forms the skin layer, a first glass fiber reinforcement that forms the first fiber reinforcement layer, a core material that forms the base material layer, a second glass fiber reinforcement that forms the second fiber reinforcement layer, and the back surface layer are layered together, and molded by heating and compressing, to produce the molded vehicle ceiling material in which the skin layer, the first fiber reinforcement layer, the base material layer, the second fiber reinforcement layer, and the back surface layer are integrated together.

[0012] The invention of claim 5 is characterized in that, in the method for manufacturing a molded vehicle ceiling material of claim 2, ink containing the aluminum powder is printed on the surface of a nonwoven fabric sheet to form the nonwoven fabric layer having the aluminum powder adhered thereto, the surface of the nonwoven fabric layer on which the aluminum powder is not printed is joined to the non-air-permeable film layer to form the back surface layer, and a skin material that forms the surface layer, a first glass fiber reinforcement that forms the first fiber reinforcement layer, a core material that forms the base material layer, a second glass fiber reinforcement that forms the second fiber reinforcement layer, and the back surface layer are layered together and molded by heating and compressing, to produce the molded vehicle ceiling material in which the surface layer, the first fiber reinforcement layer, the base material layer, the second fiber reinforcement layer, and the back surface layer are integrated together.

[0013] The invention of claim 6 is characterized in that in the method for manufacturing a molded vehicle ceiling material of claim 4 or 5, the printing is intaglio printing.

[0014] A seventh aspect of the present invention is the method for manufacturing a molded vehicle ceiling material according to the sixth aspect, characterized in that the intaglio printing is gravure printing.

[0015] In the present invention, aluminum powder includes aluminum powder, aluminum particles, and flaky aluminum, and will be simply referred to as aluminum powder hereinafter.

[0016] According to the present invention, it is possible to provide a molded vehicle ceiling material that can suppress peeling of vehicle parts, and a method for manufacturing the same.

[0017] 3A to 3C 。 FIG. 3B is a perspective view of a vehicle equipped with a vehicle molded ceiling material according to an embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a cross-section of a vehicle molded ceiling material according to an embodiment of the present invention. FIG. 5 is an enlarged photograph of a cross-section of a vehicle molded ceiling material according to an embodiment of the present invention. FIG. 6 is an enlarged photograph of a cross-section of a vehicle molded ceiling material according to an embodiment of the present invention. FIG. 7 is an enlarged photograph of a cross-section of a vehicle molded ceiling material according to an embodiment of the present invention, taken at a larger magnification than FIGS. 3A to 3C . FIG. 8 is an enlarged photograph of a cross-section of a vehicle molded ceiling material according to an embodiment of the present invention, taken at a larger magnification than FIGS. 3A to 3C . FIG. 9 is a schematic diagram showing the adhesion state of aluminum powder to the fibers of a nonwoven fabric in a vehicle molded ceiling material according to an embodiment of the present invention. FIG. 10 is a schematic diagram showing a state in which driving stability is evaluated by driving each sample attached to a vehicle molded ceiling. FIG. 11 is a diagram schematically explaining the fluctuation state of positive ions in the driving state of FIG. 6. FIG. 12 is a diagram schematically explaining the fluctuation state of positive ions in the driving state of FIG. 6. FIG. 13 is a diagram showing the evaluation results of driving stability in a driving test for each sample.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the following description of the preferred embodiments is merely exemplary in nature.

[0019] FIG. 1 shows a vehicle 1 to which a vehicle molded ceiling material 10 of the present invention is applied. FIG. 2 is a cross-sectional view schematically illustrating the cross section of the vehicle molded ceiling material 10 of the present invention. As shown in FIG. 1, the vehicle molded ceiling material 10 is panel-shaped and is disposed on the interior side of a roof panel 2 of the vehicle 1. As shown in FIG. 2, the vehicle molded ceiling material 10 includes a first fiber reinforcement layer 21 on the interior side of a base material layer 20 and a skin layer 30 on the interior side of the first fiber reinforcement layer 21. The vehicle molded ceiling material 10 also includes a second fiber reinforcement layer 22 on the exterior side of the base material layer 20 (the roof panel 2 side) and a back surface layer 40 on the exterior side of the second fiber reinforcement layer 22 (the roof panel 2 side). Note that FIG. 2 shows a partial cross section of the vehicle molded ceiling material 10 in an exaggerated manner for clarity.

[0020] 2, the base layer 20 has a core material (not shown) that forms the base layer 20. The core material is preferably, for example, polyurethane foam, polyethylene foam, or the like, with rigid polyurethane foam being particularly preferred.

[0021] The first fiber reinforcement layer 21 and the second fiber reinforcement layer 22 are made of, for example, a commonly known glass fiber mat (first glass fiber reinforcement material, second glass fiber reinforcement material). When molding the vehicle molded ceiling material 10, the first fiber reinforcement layer 21 and the second fiber reinforcement layer 22 are coated with an isocyanate-based adhesive to bond them to the base layer 20 and the like.

[0022] The skin layer 30 includes a skin material 32 .

[0023] The skin material 32 is, for example, tricot, soft urethane foam, moldable knit, fabric, nonwoven fabric, suede-like synthetic leather, PVC (polyvinyl chloride) leather, TPE (thermoplastic elastomer) sheet, or the like.

[0024] The back surface layer 40 includes, for example, a non-air-permeable film layer 41 and a nonwoven fabric layer 45 in this order from the base material layer 20 side toward the outside of the vehicle cabin.

[0025] The breathable film layer 41 is made of a breathable film 43 (for example, a CPP film). The breathable film 43 may be made of a polyamide resin or the like.

[0026] The nonwoven fabric layer 45 is formed, for example, by applying aluminum powder 52 in a random, speckled pattern to the surface of a nonwoven fabric sheet 46 obtained by spunlacing a web of PET resin (polyethylene terephthalate resin). In this embodiment of the present invention, the aluminum powder 52 clings to the fibers 47 of the nonwoven fabric sheet 46. The nonwoven fabric sheet 46 may also be formed, for example, by spunbonding a web of PET resin.

[0027] The aluminum powder 52 is randomly and speckled on the surface of the nonwoven fabric sheet 46, making it non-conductive. Therefore, even if a wire harness or the like is attached to the surface of the nonwoven fabric sheet 46, there is no risk of it becoming conductive.

[0028] (Nonwoven Fabric Layer 45) The nonwoven fabric layer 45 is provided to prevent abnormal noise (for example, to prevent abnormal noise caused by interference between the back surface layer 40 and vehicle components). The nonwoven fabric layer 45 has a basis weight of 25 g / m ２ ~50g / m ２ It is preferable to set the following.

[0029] (Ink 50) The ink 50 is a general ink containing the aluminum powder 52 to be applied, and is not particularly limited. For example, in a wet state during application (printing), an ink containing 10 to 20% by weight of ink resin as the main component, 40 to 90% by weight of solvent, 3 to 5% by weight of aluminum powder, 1 to 5% by weight of auxiliary agent, and 1 to 5% by weight of hardener can be applied.

[0030] The ink 50 is a general ink containing the aluminum powder 52 to be applied, and is not particularly limited. For example, in a wet state during application (printing), an ink containing 10 to 20% by weight of ink resin as the main component, 40 to 90% by weight of solvent, 3 to 5% by weight of aluminum powder, 1 to 5% by weight of auxiliary agent, and 1 to 5% by weight of hardener can be applied.

[0031] The aluminum powder 52 originates from the aluminum powder 52 contained in the ink 50, and the amount of aluminum powder 52 to be attached to the nonwoven fabric sheet 46 may be adjusted as desired depending on the area of ​​the molded ceiling, the vehicle structure, etc. The ratio of the aluminum powder 52 in the ink 50 may be set according to the amount of aluminum powder 52. The amount of ink 50 to be applied may be set taking into consideration the ease of application and drying of the ink 50.

[0032] The aluminum powder 52 is not particularly limited as long as it is fine, such as clumped aluminum particles or aluminum flakes, but it is preferable that the size of the aluminum powder 52 is in the range of 1 to 150 μm, for example. Note that the size of the aluminum powder 52 may vary within the above range.

[0033] (Method of manufacturing the vehicle molded ceiling material 10) One side of the nonwoven fabric sheet 46 that forms the nonwoven fabric layer 45 is heat-welded to the non-air-permeable membrane layer 41 to form the back surface layer 40. Next, ink containing aluminum powder 52 is printed (intaglio printing) on ​​the other side of the nonwoven fabric sheet 46 of the back surface layer 40. A thermoformable rigid urethane foam sheet is prepared as the base layer 20. Sheets formed into a mat shape are prepared as the first fiber reinforcement layer 21 and the second fiber reinforcement layer 22. A surface layer 30 made of tricot and soft urethane foam is prepared.

[0034] Thereafter, the surface layer 30, the first fiber reinforcement layer 21, the base layer 20, the second fiber reinforcement layer 22, and the back surface layer 40 are stacked in this order, and then pressed with a heated mold to form the shape of the vehicle molded ceiling material 10. In other words, the surface material 32 that forms the surface layer 30, the first glass fiber reinforcement that forms the first fiber reinforcement layer 21, the core material that forms the base layer 20, the second glass fiber reinforcement that forms the second fiber reinforcement layer 22, and the back surface layer 40 are stacked, and then heated and compressed to form the vehicle molded ceiling material 10, in which the surface layer 30, the first fiber reinforcement layer 21, the base layer 20, the second fiber reinforcement layer 22, and the back surface layer 40 are integrated together. Note that the molding conditions for the vehicle molded ceiling material 10 are the same as those for normal molding, and therefore a description thereof will be omitted here.

[0035] In the present invention, aluminum powder is attached to or wrapped around the surface of the nonwoven fabric by a method such as printing ink containing aluminum powder directly onto the nonwoven fabric, so when a part is attached to such a surface, it sticks to or wraps around the uneven fibers of the nonwoven fabric and is therefore difficult to peel off.

[0036] In contrast, the prior art results in easy peeling. The reason for this is explained below. In the case of a film in which an aluminum vapor deposition film is applied, as in the prior art 1, the aluminum vapor deposition film forms a flat surface, resulting in easy peeling of components attached to the surface. Also, in the case of a film containing aluminum powder (aluminum film) adhered to another film, the aluminum powder particles are arranged in parallel with gaps. Furthermore, another aluminum film is layered on top so as to cover these gaps with aluminum powder, resulting in multiple layers of aluminum film. In plan view, it looks like aluminum powder is spread out. In this technology, too, the aluminum film layer forms a flat surface, resulting in easy peeling of components attached to the surface.

[0037] Furthermore, when the molded ceiling of the present invention was assembled into a vehicle and test-driven, it was found to be significantly easier to drive than conventional molded ceilings, allowing for smoother handling as intended. In other words, it was found that attaching aluminum powder to the surface of the nonwoven fabric not only made it harder for components such as wire harnesses and brackets to peel off, but also significantly improved the vehicle's handling stability. This is because, in the present invention, the aluminum powder attached to the nonwoven fabric is dispersed in a patchy pattern, functioning like a capacitor that temporarily stores an electric charge, and the edges of the separated and independent aluminum powder particles function like discharge terminals (or discharge points), resulting in excellent charge storage and discharge capabilities for the large amount of aluminum powder. As a result, the large amount of aluminum powder can repeatedly store and discharge electricity, which is believed to suppress airflow turbulence through the roof panel and contribute to improved handling stability.

[0038] As will be explained in detail later, in the present invention, the aluminum powder adheres to the surface of the nonwoven fabric, conforming to the uneven surface of the nonwoven fabric, resulting in the aluminum powder particles being dispersed and oriented in various directions in three dimensions. Because the individual aluminum powder particles are separated and independently attached to the surface of the nonwoven fabric, they exhibit excellent temporary power storage capabilities, and because each aluminum powder particle has edges, these edges function like discharge terminals. In particular, because the aluminum powder particles are oriented in various directions in three dimensions, many edges of the aluminum powder particles are raised, and each edge functions like a discharge terminal. Therefore, printing aluminum powder directly on the nonwoven fabric results in excellent power storage and discharge capabilities. As a result, when the molded roof of the present invention is used in a vehicle, turbulence of the air flowing inside and outside the roof panel of the vehicle body can be suppressed, resulting in stable driving stability, handling, and improved handling. The evaluation of handling stability will be explained in detail later.

[0039] Furthermore, since the nonwoven fabric layer 45 contains minute spaces, it functions as a heat insulating layer, so that when a heated mold is used to form the vehicle ceiling material 10, the heat from the mold is less likely to be transmitted to the breathable film 43 (breathable membrane layer 41). This prevents the breathable film 43, which has melted due to the heat transmitted from the mold, from adhering to the mold together with the aluminum powder 52. This makes it possible to reduce the time and cost required for maintenance such as cleaning of the mold.

[0040] (Example) As an example of the present invention, the following was produced. A nonwoven fabric sheet 46 (nonwoven fabric layer 45) made by spunlacing a polyester resin fiber web was used as a nonwoven fabric sheet with a basis weight of 50 g / m ２ One surface (interior side of the vehicle cabin) of the nonwoven fabric sheet 46 (nonwoven fabric layer 45) is joined to the non-air-permeable membrane layer 41, and the two are heated and fused to form the back surface layer 40. Next, ink 50 containing aluminum powder 52 is gravure printed on the other surface (exterior side of the vehicle cabin) of the nonwoven fabric sheet 46 of the back surface layer 40. The ink 50 used is from the LP Bio SX series manufactured by Toyo Ink Co., Ltd., and is a type containing flake aluminum as the aluminum powder 52. The amount of ink 50 applied (printed) to the nonwoven fabric sheet 46 in a wet state is 12 g / m ２The aluminum powder 52 is mainly composed of flake aluminum, and is contained in the ink 50 in a wet state at a concentration of 0.48 g / m ２ The nonwoven fabric layer 45 is heated and dried, for example, to dry the ink 50 and make it into a dry state.

[0041] A part of the back surface layer 40 was cut out and used as sample A. The amount of ink 50 printed on sample B was 24 g / m ２ , sample C is 34 g / m ２ The rest was the same as sample A.

[0042] 3A, 3B, and 3C are micrographs (magnification: 50 times) of the surfaces of the nonwoven fabric sheets 46 of the back layer 40 of the samples A, B, and C.

[0043] In sample A shown in Fig. 3A, the white parts are fibers 47. The shiny, particle-like parts are aluminum powder 52. As can be seen from Fig. 3A, aluminum powder 52 is partially dispersed among fibers 47 of nonwoven fabric sheet 46.

[0044] In sample B of FIG. 3B, the amount of aluminum powder 52 is increased compared to sample A of FIG. 3A, so there is a greater amount of aluminum powder 52 that appears to shine white.

[0045] In sample C of FIG. 3C, the amount of aluminum powder 52 is further increased compared to sample B of FIG. 3B, and therefore a large amount of white shining aluminum powder 52 is observed.

[0046] As the amount of aluminum powder 52 in the ink 50 increases, the amount of aluminum powder 52 adhering to the surface of the fibers 47 also increases, but the state in which the aluminum powder 52 is randomly dispersed and adhered to the surface of the fibers 47 remains unchanged. The fibers 47, which are tangled and oriented in various directions in a three-dimensional manner, form an uneven surface, so when the ink 50 containing aluminum powder 52 is gravure printed, the aluminum powder 52 is dispersed randomly and partially adheres to the convex and concave surfaces of the fibers 47. In particular, the ink 50 containing aluminum powder 52 adheres to the convex surfaces of the concave surfaces.

[0047] When the ink 50 is applied to the nonwoven fabric sheet 46 in a wet state and then dried to a dry state, the amount of ink 50 applied to the nonwoven fabric sheet 46 is 12 g / m ２to 2.6 g / m ２ and for sample B it is 24 g / m ２ to 5.3 g / m ２ and for sample C it is 34 g / m ２ to 7.5 g / m ２ It is believed that most of the ink components 51 in the ink 50 volatilize and disappear without adhering to the fibers 47 of the nonwoven fabric sheet 46. In the present invention, it is believed that some of the aluminum powder 52 also flows away without adhering to the fibers 47, but since it is difficult to measure how much aluminum powder 52 adheres to the fibers 47 and how much aluminum powder 52 does not adhere to the fibers 47, it is assumed that all of the aluminum powder 52 in the wet ink 50 adheres to the fibers 47.

[0048] A PET resin spunlace nonwoven fabric was used to observe the surface of the nonwoven fabric layer 45 in the back surface layer 40 in more detail. Sample D was prepared as a nonwoven fabric sheet 46 made of spunlace nonwoven fabric on the surface of which aluminum powder 52 was not intaglio printed, and Sample E was prepared as a nonwoven fabric sheet 46 on the surface of which aluminum powder 52 was intaglio printed.

[0049] A portion of the back surface layer 40 was cut out, and the surface of the nonwoven fabric sheet 46 was observed with a scanning electron microscope (magnification: 1,000 times). Fig. 4A shows the observation result of the surface of sample D. Fig. 4B shows the observation result of the surface of sample E.

[0050] In sample D of FIG. 4A , the fibers 47 of the nonwoven fabric sheet 46 are tangled in various directions, forming an uneven surface. In contrast, in sample E of FIG. 4B , the fibers 47 are tangled in various directions, but ink 50 containing aluminum powder 52 is applied to the surfaces of the fibers 47 in a partially random and patchy manner. In particular, in the outermost surface of the fibers 47 and in the areas where adjacent fibers 47 are close to each other, some areas of ink 50 containing aluminum powder 52 are observed, connecting the fibers in a bridge-like manner. However, even in the outermost surface of the fibers 47 where adjacent fibers 47 are far apart, no bridge-like application is observed, and only a thin layer of ink 50 or aluminum powder 52 is applied to the surfaces of the fibers 47, or almost none at all. Furthermore, most of the surfaces of the fibers 47 recessed from the outermost surface are free of ink 50 or aluminum powder 52. In other words, the amount of aluminum powder 52 applied to the concave surfaces is less than that of the convex surfaces. The aluminum powder 52 is dispersed and adheres to the surface of the fibers, with the most adhered to the outermost surface. This aluminum powder temporarily stores and then discharges the stored charge. In other words, it is capable of repeated charging and discharging. In particular, the fibers of the nonwoven fabric are intertwined in a three-dimensional, uneven pattern, and the aluminum powder adheres to the surface of these fibers. Therefore, the aluminum powder is not aligned in the same direction in a plane, but is adhered in various directions in a three-dimensional manner. Because the individual aluminum powder particles are oriented vertically, horizontally, or diagonally, the edges of the dispersed aluminum powder particles are exposed, functioning as if they were terminals for self-discharge. Because there is a large amount of aluminum powder that functions as a terminal for self-discharge, the molded ceiling of this embodiment of the present invention has excellent discharge properties.

[0051] The aluminum powder adheres or clings to the fiber surface of the nonwoven fabric, which is oriented in various directions and has a three-dimensional shape, as shown in Figure 5. The aluminum powder adheres in various directions, such as up and down, left and right, diagonally, etc. Furthermore, each aluminum powder particle is almost independent and separate, and each aluminum powder particle is not simply circular or oval, but has a sharp, flake-like shape, which can function as a discharge terminal.

[0052] (Peel Strength) Samples A, B, and C were prepared as examples of the present invention. In addition, sample H of Comparative Example 1 was prepared for comparison with the examples of the present invention.

[0053] Sample H of Comparative Example 1 was prepared by bonding an aluminum vapor-deposited film, which was formed by vapor-depositing aluminum powder onto a film, to a non-air-permeable film layer similar to that of the present invention.

[0054] The peel strength was measured using an Autograph AG-Xplus 10KN manufactured by Shimadzu Corporation, by holding the sample in a low-temperature bath at -30°C ± 2°C for 2 hours, and then peeling at a tensile speed of 200 mm / min in this temperature atmosphere. The peel strength (N) was measured as the average of three samples for each sample.

[0055] The peel strengths were 122.7 N for Sample A of the present invention, 122.3 N for Sample B, and 123.3 N for Sample C, and 51.6 N for Sample H of Comparative Example 1. The present invention clearly had superior peel strength (peel resistance) compared to Comparative Example 1. This indicates that the present invention, in which aluminum powder 52 is attached to the surface of nonwoven fabric sheet 46, exhibited an excellent effect of preventing peeling when vehicle components (not shown) such as brackets and wire harnesses were attached to nonwoven fabric layer 45 with an adhesive such as hot melt. This is thought to be because, in the cases of Samples A, B, and C of the present invention, the adhesive clung to fibers 47 of nonwoven fabric layer 45.

[0056] On the other hand, in sample H of Comparative Example 1, the aluminum vapor-deposited film was flat and therefore more susceptible to peeling than in the present invention. Thus, if the aluminum vapor-deposited film of Comparative Example 1 has a flat surface or a flat film rather than an uneven surface like nonwoven fabric layer 45 of the present invention, it can be said that when vehicle parts such as brackets and wire harnesses are attached with an adhesive, they are more likely to peel off.

[0057] Furthermore, Samples A, B, and C of the present invention were able to reduce the impact noise compared to Sample H. Although the detailed reasons for this are not clear, it is thought that this is because the aluminum powder is dispersed and adheres to and / or wraps around the nonwoven fabric in a mottled manner, thereby softening the impact noise or reducing reflected sound, and because the surface of the nonwoven fabric is uneven and this uneven state is maintained even after printing with aluminum powder, resulting in excellent soundproofing properties.

[0058] It is also known that a vehicle body becomes positively charged while in motion. This positive static electricity can cause positively charged airflow to separate from the flow along the charged vehicle body surface, resulting in poor driving performance and handling stability. One solution to this problem is reportedly to neutralize and neutralize the positive potential by self-discharge, which generates negative air ions in response to the positive potential. It is believed that significant results can be achieved by adopting this self-discharge method in a large-area molded ceiling that is positioned along the roof interior side of the roof. For example, metal pieces could be attached to almost the entire surface of the molded ceiling facing the roof panel. Specifically, the following methods could be considered: (a) attaching a film vapor-deposited with aluminum powder to almost the entire surface of the molded ceiling facing the roof panel; (b) attaching a film printed with ink containing aluminum powder; or (c) directly printing ink containing aluminum powder on the nonwoven fabric that forms the surface of the molded ceiling facing the roof panel, as in the present invention. We investigated which of these three methods would be more effective in improving handling stability.

[0059] Since the verification experiment used a commonly used molded ceiling, detailed description will be omitted. A vehicle was prepared with a rigid urethane foam base layer, reinforcement layers made of glass fiber mats on both sides of the base layer, a skin layer consisting of tricot and soft urethane foam on the surface of one of the reinforcement layers, and a non-air-permeable membrane layer as a backing layer. It would be best to prepare and test the following structures on almost the entire surface of the roof panel side of the molded ceiling: (a) a film with aluminum powder vapor-deposited on the surface of the non-air-permeable membrane layer; (b) a film with aluminum powder-containing ink printed on the surface of the non-air-permeable membrane layer; or (c) a non-woven fabric layer on the surface of the non-woven fabric layer with aluminum powder-containing ink printed directly on the surface of the non-woven fabric layer. However, at this time, a simple method was used to conduct the experiment shown in Figure 6. Figure 6 is a cross-sectional view showing a molded ceiling 10 and a roof panel 2, showing each sample S attached to the interior side of the molded ceiling with adhesive tape T. 3 denotes a reinforcement.

[0060] A 200 mm x 220 mm sample piece was attached to the interior side of the molded ceiling of a vehicle equipped with the above-mentioned molded ceiling, and the vehicle was driven to perform a sensory evaluation of the handling stability. The samples used were parts of the above-mentioned molded ceiling, and consisted of a non-permeable membrane layer and a spunlace nonwoven fabric as the backing layer. Sample D1 was used as the sample without aluminum powder intaglio printing on the outer surface of the nonwoven fabric, and samples E1, E2, and E3 were used as samples with aluminum powder intaglio printing on the surface of the nonwoven fabric sheet. F1 was an example in which a film vapor-deposited with aluminum powder was attached to the surface of only the non-permeable membrane layer without a nonwoven fabric sheet, and G1 was an example in which a film printed with ink containing aluminum powder was attached to the surface of only the non-permeable membrane layer without a nonwoven fabric sheet. The aluminum ink was 3 g / m for samples E1, E2, and E3. ２ , 5 g / m ２ , 9 g / m ２ When printing with this ink containing aluminum, the printed wet weight is 12 g / m ２ If the ink is made into aluminum powder, the density is 0.6 g / m ２ That is, samples E1, E2, and E3 each contain 0.6 g / m of aluminum powder. ２ , 1.0 g / m ２, 1.8 g / m ２ It includes.

[0061] Sample F1 was an aluminum-deposited film prepared by forming a 0.05 μm aluminum-deposited layer on a base film, while Sample G1 was a film prepared by gravure coating an OPET film with a coating material containing flaky aluminum flakes and a resin, with the flaky aluminum flakes aligned parallel to the surface of the coating.

[0062] Each sample S was then attached to the interior side of the molded ceiling 10 with adhesive tape T, as shown in Figure 6. The handling stability felt by the driver of the vehicle was evaluated when the vehicle was driven with each sample attached and when it was partially removed. The reason for conducting the experiment with the sample attached to the molded ceiling and when it was partially removed was to confirm the difference between when there is air flow between the molded ceiling and the sample and when there is no air flow.

[0063] Figures 7A to 7C are schematic diagrams showing the behavior of positive ions in each sample S (i.e., samples D1, E1, E2, E3, F1, and G1) when the vehicle is driven with the tape still attached and when the tape is partially removed. While it is impossible to actually measure the state in which positive ions are accumulated and released, we hypothesize that the behavior is as follows. As shown in Figure 7A, when sample S is attached, positive ions accumulate on the surface of the molded ceiling side of sample S. There was no significant difference in this state among samples E1, E2, E3, F1, and G1. Furthermore, no accumulation of positive ions was observed in sample D1. Then, when a portion of the adhesive tape T was peeled off, a gap was created between sample S and the molded ceiling, generating airflow. At this time, we observed whether the positive ions accumulated on the surface of sample S were released. Figure 7B shows samples E1, E2, and E3 of the present invention. As shown in Figure 7B, a large amount of positive ions appears to have been released in all cases. On the other hand, Figure 7C shows samples F1 and G1. As shown in FIG. 7C, it appears that the amount of positive ions released was small in samples F1 and G1.

[0064] The handling stability was evaluated on a five-point scale: "A" (particularly excellent), "B" (very good), "C" (slightly improved), "NC" (unchanged), and "D" (worsened). The results are shown in Figure 8.

[0065] As shown in Figure 8, for samples E1, E2, and E3, the handling stability was "A" or "B" whether the sample was attached or partially peeled off. For samples F1 and G1, the handling stability was "B" when the sample was attached, but "C" when it was partially peeled off. Furthermore, for sample D1, the handling stability was "NC" whether it was attached or partially peeled off. Since sample D1 only had nonwoven fabric on the surface and no metal pieces to discharge, self-discharge did not occur, and the handling stability was the same as before.

[0066] Furthermore, the reason why samples F1 and G1 showed such poor handling stability is that when a film with vapor-deposited aluminum powder or a film printed with ink containing aluminum powder is attached, the aluminum powder is arranged as a flat surface on the surface of the roof panel side of the molded ceiling. Therefore, when this type of film surface is used, the edge part where the discharge function of the aluminum pieces works is almost limited to the aluminum pieces on the periphery of the sample sheet, which weakens the discharge function and, as a result, it is thought that the handling stability was not as good as expected.

[0067] On the other hand, in samples E1, E2, and E3 of the present invention, as shown in Figure 5, aluminum powder is dispersed and independently attached to the three-dimensional fiber surface, and even in a planar view, the aluminum powder is present at intervals. Because the aluminum powder is attached or clings to the uneven fibers that are entangled with the nonwoven fabric fibers, the aluminum powder is dispersed and attached to the protruding parts of the uneven fibers and the parts that are arranged three-dimensionally at an angle. In other words, since the aluminum powder is dispersed and attached in many cases with individual edges that stand out, it is predicted that discharge from the edges occurs actively.

[0068] As mentioned above, when a film vapor-deposited with aluminum powder or a film printed with ink containing aluminum powder is attached to the entire surface of the roof panel side of a molded ceiling, if a vehicle part (not shown) such as a bracket or a wire harness is attached to the nonwoven fabric layer 45 with an adhesive such as a hot melt, the vehicle part may peel off if exposed to a harsh environment. In contrast, in the present invention, when a vehicle part (not shown) such as a bracket or a wire harness is attached to the nonwoven fabric layer 45 with an adhesive such as a hot melt, the aluminum powder adheres to the uneven surface of the nonwoven fabric and clings to it in some positions, thereby providing the excellent effect of preventing peeling.

[0069] As described above, the present invention not only provides the excellent function of preventing components such as wire harnesses and brackets from peeling off when attached to the back side of the molded ceiling, but also allows aluminum powder to adhere to the surface of the nonwoven fabric on the roof panel side of the molded ceiling, and in some cases even wrap around it. Because the fibers of the nonwoven fabric are entangled in a three-dimensional, uneven pattern, the aluminum powder also adheres to the fibers in a three-dimensional, uneven pattern according to the fibers of the nonwoven fabric. A high proportion of the individual aluminum powder particles adhere in a dispersed manner with sharp edges. Because the aluminum powder particles are dispersed, they have excellent temporary charge storage capabilities, and because the individual aluminum powder particles adhere with sharp edges, they also have excellent self-discharge capabilities. The aluminum powder of the present invention repeatedly stores and discharges electricity, thereby exhibiting excellent effects in preventing positively charged airflow from separating from the flow along the charged vehicle body surface, thereby exhibiting excellent functions such as maneuverability (e.g., handling) and driving stability.

[0070] These results suggest that when aluminum powder is applied to the surface of the nonwoven fabric of a molded ceiling facing the roof panel, the molded ceiling is neutralized and de-electrified, lowering the potential of the molded ceiling, ultimately lowering the potential of the roof formed of steel sheets. In other words, by applying aluminum powder to the molded ceiling, the potential of the roof is indirectly lowered via the air layer between the molded ceiling and the roof. As a result, separation of airflow from the outer surface of the roof can be suppressed, thereby suppressing a decrease in downforce that pushes down on the vehicle body. Furthermore, separation of airflow from the longitudinal direction of the vehicle in a direction inclined from the vehicle's longitudinal direction during cornering or when exposed to a crosswind can be suppressed, thereby suppressing changes in the aerodynamic characteristics in the yaw direction. As a result, handling stability and ride comfort can be improved.

[0071] Furthermore, in the above embodiment, an example was described in which the nonwoven fabric sheet 46 that forms the nonwoven fabric layer 45 and the non-air-permeable film layer 41 are joined to form the back surface layer 40, and the ink 50 containing aluminum powder 52 is printed on the back surface layer 40. However, it is also possible to print the ink 50 containing aluminum powder 52 on the surface of the nonwoven fabric sheet 46 to form the nonwoven fabric layer 45 having the aluminum powder 52 attached thereto, and then join the surface of the nonwoven fabric layer 45 on the side on which the aluminum powder 52 is not printed to the non-air-permeable film layer 41 to form the back surface layer 40.

[0072] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0073] The present invention is suitable for a molded vehicle ceiling material and a method for manufacturing the same.

Claims

1. A molded ceiling material for a vehicle in the form of a panel arranged on the interior side of a roof panel of a vehicle, comprising: a base layer; a first fiber reinforcement layer provided on the interior side of the base layer; a second fiber reinforcement layer provided on the roof panel side of the base layer; a skin layer provided on the interior side of the first fiber reinforcement layer; and a back layer provided on the roof panel side of the second fiber reinforcement layer, wherein the back layer has, in order from the interior side, a non-breathable membrane layer and a non-woven fabric layer, and the non-woven fabric layer has aluminum attached to its surface.

2. A molded ceiling material for vehicles according to claim 1, wherein the aluminum is aluminum powder, and the aluminum powder is dispersed and adhered to the surface of the nonwoven fabric layer.

3. A molded ceiling material for vehicles according to claim 2, characterized in that the aluminum powder is derived from aluminum powder contained in ink.

4. A method for manufacturing a molded vehicle ceiling material as set forth in claim 2, characterized in that one side of a nonwoven fabric sheet forming the nonwoven fabric layer is joined to the non-breathable film layer to form a back layer, the ink containing aluminum powder is printed on the other side of the nonwoven fabric sheet, a skin material forming the skin layer, a first glass fiber reinforcement material forming the first fiber reinforcement layer, a core material forming the base layer, a second glass fiber reinforcement material forming the second fiber reinforcement layer, and the back layer are layered together and molded by heating and compressing, to produce the molded vehicle ceiling material in which the skin layer, first fiber reinforcement layer, base layer, second fiber reinforcement layer, and back layer are integrated.

5. A method for manufacturing a molded vehicle ceiling material as claimed in claim 2, comprising printing ink containing the aluminum powder on the surface of a nonwoven fabric sheet to form the nonwoven fabric layer having the aluminum powder adhered thereto, joining the surface of the nonwoven fabric layer on which the aluminum powder is not printed with the nonwoven fabric layer to form the back layer, and stacking a skin material that forms the surface skin layer, a first glass fiber reinforcement material that forms the first fiber reinforcement layer, a core material that forms the base layer, a second glass fiber reinforcement material that forms the second fiber reinforcement layer, and the back layer, and molding by heating and compressing to produce the molded vehicle ceiling material in which the surface skin layer, the first fiber reinforcement layer, the base layer, the second fiber reinforcement layer, and the back layer are integrated.

6. A method for manufacturing a molded ceiling material for a vehicle according to claim 4 or 5, characterized in that the printing is intaglio printing.

7. A method for manufacturing a molded vehicle ceiling material according to claim 6, characterized in that the intaglio printing is gravure printing.

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