Film, ceiling material, vehicle, and noise reduction method

Abstract

[PROBLEM] To reliably improve the steering stability of a vehicle. [SOLUTION] A film (50) is provided to a vehicle comprising: a plurality of electronic devices that control steering of the vehicle; and a body (2) that is conductive and that is electrically connected to at least one of the plurality of electronic devices. The film (50) comprises: a conductor layer (51) that is disposed facing the body (2) with an air layer (A1) interposed therebetween, and that includes a conductor; and a resin layer (52) that is laminated on the conductor layer (51).

Description

Film, ceiling material, vehicle, and noise reduction method

[0001] The present invention relates to a film, a ceiling material, a vehicle, and a noise reduction method.

[0002] In recent years, there have been increasing demands on vehicle components from various viewpoints. For example, Patent Document 1 discloses a vehicle in which a conductive coating is provided on the inside of a bumper cover, which is an example of an exterior component, in order to improve the vehicle's handling stability by neutralizing and eliminating static electricity that has accumulated on the vehicle.

[0003] Patent No. 6168157

[0004] A vehicle is equipped with electronic devices related to the vehicle's maneuverability. Noise may occur in the current flowing through the wiring of the electronic devices due to external or internal influences of the vehicle. If noise occurs in the current, the responsiveness of the electronic devices may decrease, which may affect the vehicle's maneuverability. The vehicle disclosed in Patent Document 1 does not anticipate the occurrence of noise in the current flowing through the wiring of the electronic devices. One aspect of the present invention aims to reliably improve the vehicle's maneuverability.

[0005] In order to solve the above problems, one embodiment of the present invention provides a film that is provided on a vehicle that includes a plurality of electronic devices that control the operation of the vehicle and a body that is electrically connected to at least one of the plurality of electronic devices and is conductive, and that includes: a conductor layer that is arranged opposite the body via an air layer and includes a conductor; and a resin layer that is laminated on the conductor layer.

[0006] Furthermore, a noise reduction method according to one aspect of the present invention is a noise reduction method for a vehicle having a plurality of electronic devices that control vehicle operation and a conductive body, which reduces noise from current flowing from an electronic device electrically connected to the body to the body among the plurality of electronic devices, and includes providing a film on the vehicle so that the film is positioned opposite the body with an air layer interposed between the film and the body.

[0007] According to one aspect of the present invention, a film having a conductive layer containing a conductor is disposed opposite a conductive body, with an air layer, which is an insulator, interposed between them. Therefore, the body, air layer, and conductive layer sandwich the insulator between the conductors, functioning like a capacitor. With this configuration, noise in the current flowing from electronic devices to the body, caused by external or internal influences of the vehicle, is reduced by the rectification action of the capacitor, stabilizing the ground potential of the body. This reduces the impact of noise on the electronic devices installed in the vehicle, improving the responsiveness of the electronic devices and reliably improving the vehicle's handling stability.

[0008] FIG. 1 is a schematic diagram showing the configuration of a vehicle according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an electric power steering device equipped in the vehicle shown in FIG. 1. FIG. 3 is a cross-sectional view showing the configuration of a ceiling material equipped in the vehicle shown in FIG. 1. FIG. 4 is a diagram showing a simulation test device for evaluating noise reduction, used in Example 1 of the present invention. FIG. 5 is a graph showing the results of measuring the surface potential of a sample using the simulation test device shown in FIG. 4. FIG. 6 is a graph showing the results of measuring the surface potential of a sample using the simulation test device shown in FIG. 4. FIG. 7 is a graph showing the average value (seconds) of the time constant in Examples 1-1 to 1-5 and Comparative Example 1-1.

[0009] <Configuration of Vehicle 1> Fig. 1 is a schematic diagram showing the configuration of a vehicle 1 according to an embodiment of the present invention. The vehicle 1 will be described below, but the following description also includes a description of a noise reduction method for reducing noise in a current flowing from an electronic device 4 to a body 2. As shown in Fig. 1, the vehicle 1 includes a body 2, a battery 3, an electronic device 4, a ceiling material 5, and a plurality of wheels 6. Note that the vehicle 1 includes a plurality of electronic devices 4, but for convenience of explanation, only one electronic device 4 is shown in Fig. 1. The vehicle 1 is formed with a vehicle compartment RM capable of accommodating a user.

[0010] The body 2 forms the passenger compartment RM of the vehicle 1 and is a cover that covers the battery 3, the plurality of electronic devices 4, and the ceiling material 5. The body 2 is electrically connected to at least one of the plurality of electronic devices 4 and is conductive. The body 2 functions as a ground for the plurality of electronic devices 4.

[0011] An electrical path R1 is provided inside the vehicle 1. The electrical path R1 is composed of wires W1 and W2, a battery 3, and multiple electronic devices 4. The positive terminal of the battery 3 is electrically connected to the positive terminals of each of the multiple electronic devices 4 by a wire W2. The battery 3 supplies power from its positive terminal to the multiple electronic devices 4. The negative terminal of the battery 3 is electrically connected to the negative terminal of at least one of the multiple electronic devices 4 by a wire W1 via a ceiling portion 22R of the body 2.

[0012] The electronic device 4 controls the operation of the vehicle 1, for example, controlling an electric power steering device 7 (described later). The electronic device 4 is, for example, an ECU (Electronic Control Unit). The ceiling material 5 is provided above the passenger compartment RM and is disposed opposite the ceiling portion 22R of the body 2. The ceiling material 5 constitutes the ceiling of the passenger compartment RM.

[0013] <Configuration of electric power steering device 7> Figure 2 is a schematic diagram showing the electric power steering device 7 provided in the vehicle 1 shown in Figure 1. As shown in Figure 2, the electric power steering device 7 includes a speed reducer 71, a torque sensor 72, a motor 73, universal joints 74 and 75, a pinion 76, a rack 77, and a tie rod 78. The vehicle 1 also includes a steering wheel H1. The electronic device 4 shown in Figure 2 is an ECU, among the multiple electronic devices 4, that controls the electric power steering device 7.

[0014] The handle H1 is connected to a reducer 71. The reducer 71 is a reduction gear that amplifies the output of the motor 73. The motor 73 is electrically connected to the electronic device 4 by a wiring W4, and assists the steering force of the handle H1 in accordance with the current supplied from the electronic device 4.

[0015] The torque sensor 72 detects the steering torque from the steering wheel H1 and transmits a sensor signal corresponding to the detected steering torque to the electronic device 4. The torque sensor 72 is electrically connected to the electronic device 4 by a wiring W3. Based on the sensor signal received from the torque sensor 72, the electronic device 4 supplies the motor 73 with a current necessary for the motor 73 to assist in the steering force of the steering wheel H1.

[0016] The reducer 71 is connected to a pinion 76 via universal joints 74 and 75. The universal joints 74 and 75 transmit the steering force from the steering wheel H1 to the pinion 76. The pinion 76 is a gear that meshes with a rack 77. The rotational motion of the steering wheel H1 transmitted to the pinion 76 is converted into linear motion by the rack 77. The rack 77 is connected to the wheels 6 via tie rods 78.

[0017] <Configuration of ceiling material 5> Figure 3 is a cross-sectional view showing the configuration of the ceiling material 5 provided in the vehicle 1 shown in Figure 1. As shown in Figure 3, the ceiling material 5 includes a film 50, a first intermediate layer 53, a second intermediate layer 54, a third intermediate layer 55, a substrate 56, and a skin material 57, and is provided in the vehicle 1. The body 2 has a steel plate 21 and a paint layer 22, and the paint layer 22 is applied to the surface of the steel plate 21, which is a conductor.

[0018] The film 50 is provided on the vehicle 1 and includes a conductor layer 51 and a resin layer 52. The film 50 is disposed opposite the steel plate 21 of the body 2 via an air layer A1, which is an insulator. The film 50 may be configured such that the conductor layer 51 is disposed opposite the body 2 via the air layer A1, and the resin layer 52 is laminated on the side of the conductor layer 51 opposite the body 2 side, or such that the resin layer 52 is disposed opposite the body 2 side via the air layer A1, and the conductor layer 51 is laminated on the side of the resin layer 52 opposite the body 2 side. Of these, it is more preferable that the conductor layer 51 is disposed opposite the body 2 via the air layer A1, and the resin layer 52 is laminated on the side of the conductor layer 51 opposite the body 2 side.

[0019] The conductor layer 51 refers to a layer containing a conductor. Examples of the conductor layer 51 include a metal foil layer made of a metal such as aluminum, a vapor-deposited layer on which a metal such as aluminum is vapor-deposited, and a coated layer formed by dispersing metal particles such as aluminum in a resin and coating the resin. The coated layer formed by dispersing metal particles such as aluminum in a resin has a high surface resistivity and is insulating (insulating here means a surface resistivity of 1×10 １２ The conductive layer referred to in the present invention is not problematic as long as it is a layer containing a conductor, and also includes cases where the conductive layer is insulating.

[0020] Among these, a coating layer formed by dispersing metal particles such as aluminum in a resin and applying the dispersed metal particles is particularly preferred, with aluminum particles being preferred as the metal particles dispersed in the resin. It is possible to obtain a dielectric loss in a predetermined frequency band by appropriately adjusting the content of metal particles such as aluminum. Furthermore, a coating layer formed by dispersing resin-coated metal particles in a resin and applying the dispersed metal particles is preferred because the resin coating of the metal particles makes it difficult for the metal particles to aggregate, allowing the metal particles to be uniformly dispersed in the conductor layer 51.

[0021] Examples of resin layer 52 include layers made of polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamide resins such as nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 12, and terpolymers of nylon 6, nylon 66, and nylon 12; polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins; cellulose resins such as triacetyl cellulose; polyimide resins; polycarbonate resins; acrylic resins; polyvinyl alcohol resins; and ethylene-vinyl alcohol copolymers. Among these, resins with a melting point of 200°C or higher, such as polyester resins and polyamide resins, are particularly preferred because they have heat resistance when heated to form the base material of the ceiling material. In particular, using an unstretched polyamide film (sometimes referred to as "unstretched nylon film," "CNY film," or "C nylon film") as a resin layer made of polyamide is particularly preferred because of its formability, especially when used in applications where post-processing is required.

[0022] A film 50 including a conductive layer 51 containing a conductor is disposed opposite a conductive body 2 via an insulating air layer A1. Therefore, the body 2, air layer A1, and conductive layer 51 sandwich an insulator between conductors, functioning like a capacitor. With this configuration, noise in the current flowing from the electronic device 4 to the body 2, caused by external or internal influences of the vehicle 1, is reduced by the rectifying action of the capacitor, stabilizing the ground potential of the body 2. This reduces the impact of noise on the electronic device 4 provided in the vehicle 1, improving the responsiveness of the electronic device 4 and enhancing the handling stability of the vehicle 1. In the case of a coating layer formed by dispersing resin-coated metal particles in a resin and applying the coating, the metal particles act as a conductor and the resin acts as an insulator, sandwiching the insulator between the conductors, thus functioning like a capacitor. It is presumed that the greater the number of capacitors, the greater the capacitance, and therefore the greater the rectifying action of the capacitor, contributing to noise reduction. Furthermore, the greater the coating amount (thicker the coating), the greater the number of capacitors and the greater the capacitance, which is thought to contribute to better noise reduction. Increasing the metal particle filling rate also contributes to noise reduction by reducing the average spacing between adjacent particles and increasing capacitance. However, an excessively high filling rate reduces the resin content, which may reduce moldability and insulation during post-processing. Furthermore, when the conductive layer is formed by dispersing resin-coated metal particles in a resin and applying the coating, the surface resistivity is high, making the surface insulating. This reduces the risk of short circuits due to contact with wire harnesses running above the ceiling, making it particularly suitable for ceiling applications.

[0023] Here, noise refers to unnecessary voltages and currents that are generated when external electromagnetic waves are applied to the wiring W1 to W4 and the electronic device 4, etc. There are three types of noise, for example. The first is radiation noise that occurs in the current output from the electronic device 4 when electromagnetic waves from outside or inside the vehicle 1 are radiated to the electronic device 4. The second is conduction noise that occurs in the current flowing through the wiring W1, W2 connected to the electronic device 4 due to electromagnetic waves from outside or inside the vehicle 1 or electromagnetic waves generated by the electronic device 4. The third is electromagnetic induction noise that occurs in the current flowing in wiring near the current-carrying wiring due to electromagnetic waves generated from the current-carrying wiring.

[0024] Radiation noise generated in the current output from electronic device 4 and flowing through wiring W1, W2 is reduced by film 50 of ceiling material 5. Conduction noise generated in the current flowing through wiring W1, W2 is also reduced by film 50 of ceiling material 5. Electromagnetic induction noise generated in the current flowing through wiring W1, W2 is also reduced by film 50 of ceiling material 5.

[0025] In this way, noise generated in the vehicle 1 is reduced by the film 50 before it reaches the body 2. Therefore, noise in the current flowing from the electronic device 4 electrically connected to the body 2 among the plurality of electronic devices 4 to the body 2 is also reduced.

[0026] Furthermore, by providing the vehicle 1 with a film 50 that is arranged opposite the body 2 via an air layer A1, the responsiveness of the electronic device 4 is improved, and the vehicle 1 can be configured to improve the handling stability of the vehicle 1.

[0027] The conductor layer 51 containing a conductor is preferably disposed opposite the ceiling portion 22R of the body 2. This allows the conductor layer 51 to reflect radiant heat generated between the body 2 and the conductor layer 51 when heat from the sun is transmitted to the body 2. This makes it possible to improve the handling stability of the vehicle 1 while reducing the temperature rise in the passenger compartment RM below the ceiling portion 22R of the body 2.

[0028] The first intermediate layer 53 is made of, for example, polyethylene resin and is laminated on the resin layer 52 on the side opposite to the conductor layer 51. The second intermediate layer 54 is made of, for example, a nonwoven fabric made of PET (polyethylene terephthalate) resin and is laminated on the first intermediate layer 53 on the side opposite to the resin layer 52. The third intermediate layer 55 is made of polypropylene resin and is laminated on the second intermediate layer 54 on the side opposite to the first intermediate layer 53.

[0029] The substrate 56 is a layer that serves as a support layer in the ceiling material and is made of, for example, a material obtained by adding glass fiber to polypropylene resin, and is provided on the side of the third intermediate layer 55 opposite the second intermediate layer 54. The skin material 57 is disposed on the side of the film 50 opposite the body 2 and forms the ceiling surface of the passenger compartment RM of the vehicle 1. Specifically, the skin material 57 is provided on the side of the substrate 56 opposite the third intermediate layer 55. The skin material 57 may be made of, for example, PET resin, or may be a woven (knitted) fabric or a nonwoven fabric.

[0030] The ceiling material 5 is provided with a film 50 arranged opposite the body 2 via an air layer A1, and a skin material 57 that forms the ceiling surface of the passenger compartment RM of the vehicle 1, thereby enabling the formation of a ceiling material 5 that can improve the handling stability of the vehicle 1.

[0031] The film 50 functions as a radiant heat reflecting film that reflects radiant heat by including the conductive layer 51. The distance L1 between the conductive layer 51 and the body 2 is preferably 10 cm or less, for example, 3 cm. The distance L1 is the distance between the conductive layer 51 and the body 2 at their farthest points.

[0032] 1 , the ceiling material 5 is provided between the electronic device 4 and the body 2, and therefore the film 50 is also provided between the electronic device 4 and the body 2. By providing the film 50 between the electronic device 4 and the body 2, noise in the current flowing from the electronic device 4 to the body 2 can be reduced.

[0033] 1, a portion of the wiring W1 is covered by the ceiling material 5, but this is not limiting, and a portion of the wiring W1 may not be covered by the ceiling material 5 or may not be in contact with the ceiling material 5. With regard to noise transmitted through the wiring W1, the film 50 can reduce noise from the body 2, which functions as a ground, to the battery 3. This can prevent malfunction of the electronic device 4 electrically connected to the battery 3, improving the responsiveness of the electronic device 4.

[0034] Since the responsiveness of the electronic device 4 can be improved, the electronic device 4 can quickly supply the current required to assist the steering force of the steering wheel H1 to the motor 73 after receiving the sensor signal from the torque sensor 72. Also, the movement of the wheels 6 when the steering wheel H1 is steered can be quickly reflected. Therefore, the handling stability of the vehicle 1 can be improved.

[0035] The area of ​​the portion of the conductive layer 51 facing the body 2 is preferably 100 cm 2 or more.

[0036] <Method of Manufacturing Ceiling Material 5> The ceiling material 5 is manufactured by the following procedure. Specifically, first, the conductor layer 51 is printed on the resin layer 52. Next, the first intermediate layer 53 and the second intermediate layer 54 are laminated on the resin layer 52 by extrusion lamination. After the first intermediate layer 53 and the second intermediate layer 54 are laminated on the resin layer 52, the base material 56 is bonded to the second intermediate layer 54 via the third intermediate layer 55. Then, the skin material 57 is bonded to the base material 56.

[0037] While the above description concerns a ceiling material whose base material is a material obtained by adding glass fiber to polypropylene resin, the present invention is not limited thereto. For example, the film of the present invention may be bonded to a ceiling material whose base material is urethane foam. Examples of a ceiling material using a urethane foam base material include a laminate of the following layers from the body side: film with a resin layer laminated on a conductive layer / glass fiber / urethane foam (base material) / glass fiber / skin material. This ceiling material using a urethane foam base material can be formed by bonding each layer together with an adhesive.

[0038] The film of the present invention is a film that is installed in a vehicle that has a plurality of electronic devices that control the vehicle's steering and a conductive body that is electrically connected to at least one of the plurality of electronic devices.The film is arranged opposite the body via an air gap, and has a conductive layer that contains a conductor and a resin layer that is laminated on the conductive layer.Since the film improves steering stability, it can also be used for applications other than ceiling materials, such as underfloor undercovers and door trims.

[0039] 4 is a diagram showing a simulation test device 31 used in Example 1 of the present invention for evaluating noise reduction. The configuration of Example 1 is included in the present invention, but the present invention is not limited to the configuration of Example 1. The simulation test device 31 is a device for performing a test to measure the time constant of sample M2. Sample M2 will be described later.

[0040] <Time Constant> The time constant indicates the speed at which noise is reduced, and is a measure of how long it takes for the noise to be reduced. As shown in Figure 4, the simulation test device 31 includes an outer frame 32, a mounting table 33, a jack 34, and a static electricity measuring device 35.

[0041] The outer frame 32 is box-shaped and open at the front in FIG. 4 , and is made of cardboard. A sample M1 of the body 2 is placed on the top surface of the outer frame 32, and a static electricity measuring device 35 is placed above the sample M1. The sample M1 is a polyethylene terephthalate film (thickness: 12 μm) that simulates the ceiling portion 22R of the body 2, where noise accumulates. The ceiling portion 22R of the body 2 is originally made of a steel plate. However, applying a potential to the steel plate resulted in variations in the measured time constant due to natural discharge. Therefore, polyethylene terephthalate film, which exhibits less natural discharge, was used for the sample M1. The size of the sample M1 is 20 cm × 20 cm. The size of the sample M2 is 18 cm × 18 cm. A mounting base 33 and a jack 34 are placed inside the outer frame 32. The mounting base 33 is made of an acrylic plate. The jack 34 supports the mounting base 33 and allows the position of the mounting base 33 to be adjusted vertically.

[0042] Sample M2 is placed on the upper surface of mounting table 33, and the position of mounting table 33 is adjusted with jacks 34 so that the distance between samples M1 and M2 is 2 cm. This distance is in the vertical direction. Here, a notch CT is formed in the upper surface of outer frame 32, and sample M2 is positioned so as to face sample M1 across notch CT. Therefore, the thickness of air layer A1 in the vertical direction is also 2 cm.

[0043] Sample M2 is placed below sample M1. As a result, sample M1 and sample M2 are placed with an air layer A1 between them. In this state, a voltage of -10,500 V is applied to sample M1 for 20 seconds using a DC stabilized power supply (not shown), thereby charging sample M1. Charging and measurement are performed in an environment of 23°C and 30% RH. Note that samples with dust or debris attached are likely to affect static electricity measurements, so if any dust or debris is present, remove it from sample M1 and sample M2 before use.

[0044] After the predetermined voltage was applied to the sample M1 for the predetermined time, that is, after the application of the voltage to the sample M1 was stopped, measurement of the surface potential of the sample M1 was started using the static electricity measuring instrument 35. As the static electricity measuring instrument 35, an "SK-1000" manufactured by Keyence Corporation was used.

[0045] <Surface Resistivity of Film> The surface resistivity was measured at two random points on a sample cut to 100 mm x 100 mm in accordance with JIS K6911-2006 using a Digital Ultra-High Resistivity Meter 5451 manufactured by ADC Corporation, at an applied voltage of 100 V in an environment of 23°C and 50% RH.

[0046] Example 1-1 Fig. 5 is a graph showing the results of measuring the surface potential of sample M1 using the simulation test device 31 shown in Fig. 4. In the graph shown in Fig. 5, the horizontal axis represents the elapsed time from the start of measurement, in which a predetermined voltage (voltage: -10,500 V) was applied to sample M1 for a predetermined time (time: 20 seconds) (to charge sample M1), and the vertical axis represents the surface potential of sample M1. Hereinafter, the time when sample M1 was charged will be referred to as the initial time point.

[0047] Graph G1, designated by reference numeral 501 in Fig. 5, shows the relationship between the surface potential of sample M1 measured by static electricity meter 35 and the elapsed time when sample M2 is a film 50 (the film of Example 1-1) including a conductive layer 51 (a coating layer (thickness 3 µm) in which resin-coated aluminum particles are dispersed in a resin) and a resin layer 52 made of a CNY film (thickness 20 µm). Regarding graph G1, the elapsed time indicated by the intersection P1 between a tangent G1' to graph G1 at the initial point and a straight line I1 along which the surface potential of sample M1 is 0 is defined as the time constant.

[0048] For graph G1, an experiment was conducted three times to measure the elapsed time indicated by the intersection P1 of the tangent G1' to graph G1 at the initial time point and the line I1, where the surface potential of sample M1 is 0, as the time constant. The average value of the time constant was 64 seconds, as shown in Figure 8. The surface resistivity of the conductive layer side of the film was 1.5 x 10 １４ It was Omega.

[0049] The tangent line G1' is a tangent to the approximate line of the graph G2 for 3 seconds from the start of measurement. Regarding the line I1, it is assumed that the graph G1 is in a balanced state when the surface potential of the sample M1 is 0.

[0050] Here, the smaller the time constant, the steeper the slope of the tangent line G1', and the faster the absolute value of the surface potential of sample M1 decreases in graph G1. In other words, the smaller the time constant, the faster the ground potential of sample M1 in body 2 can be stabilized, and the faster the noise to body 2 is reduced. Therefore, the time constant indicates the degree of noise reduction speed.

[0051] The film 50 is preferably a film having a time constant of 68 seconds or less, which is the elapsed time indicated by the intersection P1 of the tangent G1' to the graph G1 at the initial time point and the straight line I1, where the surface potential of the sample M1 is 0. The film 50 is more preferably a film having a time constant of 65 seconds or less.

[0052] The film 50 has a time constant, which indicates the speed at which it reduces noise, of 68 seconds or less when placed opposite the body 2 with the air layer A1 between them. Therefore, by placing the film 50 opposite the body 2, the time it takes for the film 50 to reduce noise can be sufficiently shortened. This allows the ground potential of the body 2 to be stabilized.

[0053] Example 1-2 Sample M2 of Example 1-2 is a film 50 (the film of Example 1-2) including a conductive layer 51 (a coating layer (thickness 6 μm) formed from a coating liquid in which resin-coated aluminum particles are dispersed in a resin) and a resin layer 52 made of a CNY film (thickness 20 μm). For graph G2 indicated by reference numeral 502 in FIG. 5 , an experiment was conducted three times to measure the elapsed time indicated by the intersection P2 of a tangent G2′ to graph G2 at the initial time point and a straight line I1, where the surface potential of sample M1 is 0, as a time constant. The average value of the time constant was 64 seconds, as shown in FIG. 8 .

[0054] Example 1-3 Sample M2 of Example 1-3 is a film 50 (film of Example 1-3) including a conductor layer 51 (a coating layer (thickness 10 μm) formed from a coating liquid in which resin-coated aluminum particles are dispersed in a resin) and a resin layer 52 composed of a CNY film (thickness 20 μm). For graph G3 indicated by reference numeral 601 in FIG. 6 , an experiment was conducted three times to measure the elapsed time indicated by the intersection P3 of the tangent G3′ to graph G3 at the initial time point and the straight line I1, where the surface potential of sample M1 is 0, as a time constant. The average value of the time constant was 63 seconds, as shown in FIG. 8 . Furthermore, the surface resistivity of the conductor layer side of the film was 2.1×10 １４ It was Omega.

[0055] Example 1-4 Sample M2 of Example 1-4 is a film 50 (film of Example 1-4) including a conductor layer 51 (a coating layer (thickness 3 μm) formed from a coating liquid in which non-resin-coated aluminum particles are dispersed in a resin) and a resin layer 52 composed of a CNY film (thickness 20 μm). For graph G4 indicated by reference numeral 602 in FIG. 6 , an experiment was conducted three times to measure the elapsed time indicated by the intersection P4 of the tangent G4′ to graph G4 at the initial time point and the line I1, where the surface potential of sample M1 is 0, as a time constant. The average value of the time constant was 66 seconds, as shown in FIG. 8 . Furthermore, the surface resistivity of the conductor layer side of the film was 3.5×10 １３ It was Omega.

[0056] Example 1-5 Sample M2 in Example 1-5 was a polyethylene terephthalate film with a vapor-deposited layer manufactured by Saichi Kogyo Co., Ltd. (VM-PET MWR2 (water-resistant, high-adhesion type)), the film of Example 1-5). For graph G5 indicated by reference numeral 701 in FIG. 7 , an experiment was conducted three times to measure the elapsed time indicated by the intersection P5 of the tangent G5' to graph G5 at the initial time point and the line I1, where the surface potential of sample M1 was 0, as the time constant. The average time constant was 61 seconds, as shown in FIG. 8. The surface resistivity of the conductive layer side of the film was 1.2 Ω.

[0057] <Comparative Example 1-1> Sample M2 of Comparative Example 1-1 is a film (film of Comparative Example 1-1) composed only of a resin layer 52 made of a CNY film (thickness 20 μm). For graph G6 indicated by reference numeral 702 in FIG. 7, an experiment was conducted three times to measure the elapsed time indicated by the intersection P6 of the tangent G6' of graph G6 at the initial time point and the line I1, where the surface potential of sample M1 is 0, as a time constant. The average value of the time constant was 69 seconds, as shown in FIG. 8. The surface resistivity of the conductive layer side of the film was 4.9×10 １４ It was Omega.

[0058] Because the films of Examples 1-1 to 1-5 have a conductor layer and a resin layer, their time constants are 68 seconds or less, which is considered to provide a fast noise reduction rate. Furthermore, although the time constant of the film of Example 1-5 is 68 seconds or less, due to the low surface resistivity of the conductor layer (not insulating), when used in ceiling materials, care must be taken in its application because the wire harness and the conductor layer (vapor deposition layer) may come into contact and cause a short circuit. Furthermore, because polyethylene terephthalate films are difficult to stretch, and the vapor deposition layer is also difficult to stretch and prone to cracking, care must be taken in some applications that require post-processing. Furthermore, comparing the films of Example 1-1 and Example 1-4, it can be seen that the time constant of the film of Example 1-1, in which the conductor layer is formed from a coating liquid in which resin-coated aluminum particles are dispersed in a resin, is smaller than that of the film of Example 1-4, in which the conductor layer is formed from a coating liquid in which non-resin-coated aluminum particles are dispersed in a resin. As mentioned above, this is because the resin-coated aluminum particles are more dispersed, with the aluminum particles acting as conductors and the resin acting as insulators, resulting in a configuration in which the conductors sandwich the insulators, functioning like a capacitor. The greater the number of capacitors, the greater the capacitance, which is presumably why the rectification effect of the capacitors also increases, contributing to the noise reduction effect. Furthermore, comparing the films of Examples 1-1, 1-2, and 1-3, it is presumed that increasing the thickness of the coating layer (increasing the amount of coating) increases the number of capacitors and the capacitance, further contributing to the noise reduction effect.

[0059] Example 2 and Comparative Example 2 A vehicle (Example 2) equipped with a ceiling material using Example 1-1 (specifically, a conductive layer-equipped ceiling material obtained by laminating the film of Example 1-1 / first intermediate layer (polyethylene resin layer) / second intermediate layer (PET nonwoven fabric) / third intermediate layer (polypropylene resin layer) / base material (glass fiber sheet with polypropylene resin added) / surface material in this order) and a vehicle (Comparative Example 2) equipped with a ceiling material using Comparative Example 1-1 (specifically, a conductive layer-equipped ceiling material obtained by laminating the PET spunbond nonwoven fabric / first intermediate layer (polyethylene resin layer) / second intermediate layer (nylon resin layer) / third intermediate layer (polyethylene resin layer) / base material (glass fiber sheet with polypropylene resin added) / surface material in this order) were prepared, and a running experiment was conducted. The running test involved a sensory evaluation in which the vehicle of Example 2 and the vehicle of Comparative Example 2 were driven on a highway and on an ordinary road (mountain road) to compare them. (Number of drivers: 2) As a result, both drivers felt that on ordinary roads, the vehicle of Example 2 had a faster response when turning the steering wheel, and felt a sense of stability when cornering on mountain roads. Also, on expressways, the vehicle of Example 2 required fewer steering corrections and was more stable when using the lane departure prevention support system.

[0060] From the above evaluation results, it is presumed that the use of a film with a conductive layer reduces noise both inside and outside the vehicle and speeds up the response of the electric steering device, thereby improving the handling stability of the vehicle.

[0061] <Summary> The film according to aspect 1 of the present invention is a film provided on a vehicle that includes a plurality of electronic devices that control the operation of the vehicle and a body that is electrically connected to at least one of the plurality of electronic devices and has conductivity, and is configured to include a conductor layer that is arranged opposite the body via an air layer and includes a conductor, and a resin layer that is laminated on the conductor layer.

[0062] A film according to aspect 2 of the present invention may be configured such that, in the above-mentioned aspect 1, the conductive layer is positioned opposite the body via an air layer, and the resin layer is laminated on the side of the conductive layer opposite the body side.

[0063] A film according to a third aspect of the present invention may be configured in the above-mentioned first or second aspect such that the film has a time constant of 68 seconds or less measured under the following conditions.

[0064] A film according to a fourth aspect of the present invention is the film of any one of the first to third aspects, wherein the surface resistivity of the surface side of the conductive layer of the film is 1×10 １２ It may be configured to be Ω or more.

[0065] A film according to a fifth aspect of the present invention may be configured in any one of the first to fourth aspects, wherein the conductive layer is disposed opposite a ceiling portion of the body.

[0066] A film according to a sixth aspect of the present invention may be configured as in any one of the first to fifth aspects, wherein the film is provided between the electronic device and the body.

[0067] A ceiling material according to aspect 7 of the present invention may be configured to include the film of any of aspects 1 to 6 above, and a skin material that is arranged on the side of the film opposite the body side and that forms the ceiling surface of the passenger compartment of the vehicle.

[0068] A vehicle according to an eighth aspect of the present invention may be configured to include the plurality of electronic devices and the body, and the film according to any one of the first to sixth aspects.

[0069] A noise reduction method according to aspect 9 of the present invention is a noise reduction method for a vehicle having a plurality of electronic devices that control vehicle operation and a conductive body, which reduces noise from current flowing from an electronic device electrically connected to the body to the body, and which comprises providing a film on the vehicle so that the film is positioned opposite the body with an air layer interposed between the film and the body.

[0070] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0071] REFERENCE SIGNS LIST 1 vehicle 2 body 4 electronic device 5 ceiling material 22R ceiling portion 35 static electricity measuring device 50 film 51 conductive layer 52 resin layer 57 skin material A1 air layer G1 tangent G1' graph I1 straight line M1 sample P1 intersection R1 electrical path

Claims

1. A film provided on a vehicle that includes a plurality of electronic devices that control the operation of the vehicle and a body that is electrically connected to at least one of the plurality of electronic devices and has electrical conductivity, the film being characterized in that it is disposed opposite the body with an air gap therebetween, and including a conductor layer that includes an electrical conductor, and a resin layer that is laminated on the conductor layer.

2. The film according to claim 1, characterized in that the conductive layer is disposed opposite the body with an air layer between them, and the resin layer is laminated on the conductive layer on the side opposite the body.

3. The film according to claim 1, characterized in that the film has a time constant of 68 seconds or less when measured under the following conditions. <Conditions> - Measurement is performed in an environment of 23°C and 30% RH. - The film and the body sample are arranged with an air layer between them. - A voltage of -10,500V is applied to the sample for 20 seconds, and then the surface potential of the sample is measured with a static electricity meter. - In a graph showing the relationship between the surface potential of the sample measured with the static electricity meter and the elapsed time from the start of measurement when a voltage of -10,500V is applied to the sample for 20 seconds, the elapsed time indicated by the intersection of the tangent to the graph at the time point and the straight line where the surface potential of the sample is 0 is defined as the time constant.

4. The surface resistivity of the surface side of the conductive layer of the film is 1×10 １２ 2. The film according to claim 1, wherein the elastic modulus is Ω or more.

5. The film according to claim 1, wherein the conductive layer is disposed opposite a ceiling portion of the body.

6. The film according to claim 1, wherein the film is provided between the electronic device and the body.

7. A ceiling material comprising the film according to any one of claims 1 to 6, and a skin material arranged on the side of the film opposite the body side and constituting the ceiling surface of the passenger compartment of the vehicle.

8. A vehicle comprising the plurality of electronic devices and the body, and comprising the film according to any one of claims 1 to 6.

9. A noise reduction method for a vehicle having a plurality of electronic devices for controlling vehicle operation and a conductive body, the method reducing noise of a current flowing from an electronic device electrically connected to the body among the plurality of electronic devices, the method comprising providing a film on the vehicle so that the film is positioned opposite the body with an air layer interposed therebetween. The film comprises a conductive layer including a conductor and a resin layer laminated on the conductive layer.

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