Automotive horizontal member and method for manufacturing same

Abstract

An automotive horizontal member comprising a resin layer (P1) containing a thermoplastic resin and reinforcing fibers having a weight-average fiber length of 5-100 mm; and a thermally conductive layer (P2) laminated on the resin layer (P1); wherein the thermal conductivity tc1 of the resin layer (P1) satisfies formula (2), and the thermal conductivity tc2 of the thermally conductive layer (P2) satisfies formula (3). Formula (2): 0.01 W / (m·K) < tc1 < 10 W / (m·K) Formula (3): 100 W / (m·K) < tc2 < 350 W / (m·K)

Description

Automotive horizontal member and method for manufacturing the same

[0001] The present invention relates to a horizontal member for automobiles, comprising a resin layer P1 containing reinforcing fibers and a thermoplastic resin, and a heat-conducting layer P2 laminated together.

[0002] Molding materials that use reinforcing fibers as a reinforcing material have high tensile strength and tensile modulus, and a low coefficient of linear expansion, resulting in excellent dimensional stability. Furthermore, they have superior heat resistance, chemical resistance, fatigue resistance, and abrasion resistance. For these reasons, molding materials using reinforcing fibers are widely applied in automotive, sports and leisure, aerospace, and general industrial applications.

[0003] Patent Document 1 describes an impact-resistant resin used in battery cases for electric vehicles and electric hybrid trucks. This battery case has multiple electromagnetic wave shielding sheets arranged on the inside and bonded together via a conductive adhesive. The arrangement of the electromagnetic wave shielding sheets can be selected from a first arrangement in which adjacent sheets are electrically connected with a conductive material, and a second arrangement in which conductive sheets are overlapped.

[0004] Patent Document 2 describes a stampable sheet and a stampable sheet molded product produced by a papermaking method that exhibits excellent flame retardancy.

[0005] Patent Document 3 states that the amount of work per basis in a tensile test using a 25 mm wide test piece is 1 × 10⁻¹⁶ －３ ~30 x 10 －３ [(N・mm) / (g / m ２ A carbon fiber composite material is described, in which a carbon fiber sheet is used as a reinforcing material and a thermoplastic resin is used as the matrix resin.

[0006] Japanese Unexamined Patent Publication No. 2012-186125 Japanese Unexamined Patent Publication No. 11-49869 WO2013 / 179891

[0007] However, the electromagnetic shielding sheet described in Patent Document 1 was not intended to improve fire resistance.

[0008] The invention described in Patent Document 2 is manufactured by a papermaking method, resulting in excessively high springback during molding and poor moldability. Furthermore, no consideration has been given to its use as a horizontal component for automobiles. Further problems with the invention described in Patent Document 2 include: (1) excessive addition of flame retardant leads to poor moldability and high manufacturing costs; (2) the inclusion of a large amount of metal hydrate as a flame retardant results in an excessively high specific gravity of the resulting molded article; (3) halogen-based flame retardants are highly toxic to living organisms, raising concerns about increased health risks; and (4) in the case of horizontal components for automobiles, it is necessary to prevent the component from sagging during combustion (sometimes called resin drip), and this problem becomes particularly pronounced when the size of the horizontal component for automobiles is large.

[0009] The invention described in Patent Document 3 does not consider the flame-retardant properties of the horizontal member for automobiles at all. Furthermore, because the work rate is increased by increasing the single-fiber ratio, the springback rate is too high, resulting in extremely poor moldability.

[0010] Therefore, the present invention provides a horizontal automotive component with improved flame resistance by using a resin layer that transitions to a solidified layer and an expanded layer after combustion, and laminating a heat-conducting layer thereon.

[0011] To solve the above problems, the present invention provides the following means: 1. A horizontal member for automobiles having a resin layer (P1) containing reinforcing fibers with a weight-average fiber length of 5 mm or more and 100 mm or less and a thermoplastic resin, and a heat-conducting layer (P2) laminated on the resin layer (P1), wherein the thermal conductivity tc1 of the resin layer (P1) satisfies the following formula (2), and the thermal conductivity tc2 of the heat-conducting layer P2 satisfies the following formula (3). Formula (2) 0.01 W / (m·K) < tc1 < 10 W / (m·K) Formula (3) 100 W / (m·K) < tc2 < 350 W / (m·K) 2. A horizontal automotive member as described in item 1 above, wherein the thickness t1 of the resin layer (P1) satisfies the following formula (4), the thickness t2 of the heat conductive layer (P2) satisfies the following formula (5), and when the horizontal automotive member is observed 600 seconds after being heated with a burner flame so that the surface on the resin layer (P1) side reaches 1000°C, the resin layer (P1) transitions into a solidified layer (P3) in which reinforcing fiber springback has not occurred and an expanded layer (P4) in which reinforcing fiber springback has occurred, the thickness t3 of the solidified layer (P3) satisfies the following formula (6), and the thickness t4 of the expanded layer (P4) satisfies the following formula (7). Formula (4) 1.3 mm < t1 < 10.0 mm Formula (5) 0.005 mm < t2 < 1.0 mm Formula (6) t1 × 0.1 < t3 < t1 × 0.7 Formula (7) t1 × 0.3 × 1.05 < t4 < t1 × 0.9 × 8 3. A horizontal member for automobiles according to either 1 or 2 above, wherein the thermal conductivity tc3 of the horizontal member for automobiles satisfies the following formulas (8) and (9). Formula (8) 0.8 < tc3 / tc1 < 1.2 Formula (9) 0.1 W / (m・K) < tc3 < 10 W / (m・K) 4. The horizontal automotive member according to any one of claims 1 to 3, wherein the surface of the horizontal automotive member on the resin layer P1 side is exposed to flame from a burner so that the flame surface reaches 1000°C, the temperature of the surface on the heat conduction layer P2 side is measured at a position 70 mm away from the center of the flame contact position, and the curve plotted of the temperature has a region in which the slope becomes negative between 900 seconds after the start of flame contact and before 1800 seconds have elapsed.5. The resin layer (P1) contains a flame retardant, and the flame retardant is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin, and satisfies the following (a) and (b). The automotive horizontal member according to any one of the above 1 to 4. (a) The tensile strength retention rate represented by the formula (a1) is more than 0.03%. Formula (a1) Tensile strength retention rate (%) = (tensile strength B after combustion ÷ tensile strength A before combustion) × 100 (b) The work per unit area in the tensile test of the test piece after the combustion test with a width of 25 mm is 0.1 × 10. －３ [(N·mm) / (g / m ２ )] or more and 300 × 10 －３ [(N·mm) / (g / m ２ )] or less, and the maximum load per unit area is 1.1 × 10 －３ [N / (g / m ２ )] or more. 6. The resin layer (P1) has a maximum load per unit area in the range of more than 0% and less than 5% of strain in the tensile test of the test piece after the combustion test with a width of 25 mm. The automotive horizontal member according to 5 above. 7. The resin layer (P1) satisfies the following (c). The automotive horizontal member according to any one of 5 or 6 above. (c) In the tensile test of the test piece after the combustion test with a width of 25 mm, the average change rate of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% is 0.05 × 10 －３ [N / (g / m ２ )] or more and less than 300 × 10 －３ [N / (g / m ２ )]. 8. The resin layer (P1) satisfies the following (c0). The automotive horizontal member according to any one of 5 or 6 above. (c0) In the tensile test of the test piece after the combustion test with a width of 25 mm, the change amount of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% is 0.05 × 10 －３ [N / (g / m ２ )] or more and less than 300 × 10 －３ [N / (g / m ２)] is in the range of less than ). 9. The resin layer (P1) is a horizontal automotive member according to any one of 5 to 8 above, satisfying (d) below. (d) In a tensile test of a test piece with a width of 25 mm after a combustion test, the load at a strain of 0.5% to 3% [N / (g / m ２ The average rate of change of ) ] is -3.0 × 10 －３ [N / (g / m2)] or more - 0.005×10 －３ [N / (g / m) ２ )] is within the following range. 10. The resin layer (P1) is a horizontal automotive member according to any one of 5 to 8 above, satisfying the following (d0): (d0) In a tensile test on a test piece with a width of 25 mm after a combustion test, the load [N / (g / m) at a strain of 0.5% to 3% ２ The change in ) is -7.5 × 10 －３ [N / (g / m) ２ ) ] Above - 0.0125 × 10 －３ [N / (g / m) ２ )] The range is as follows: 11. The automotive horizontal member according to any one of 1 to 10, wherein the thermoplastic resin is polypropylene resin and the reinforcing fiber is glass fiber. 12. The automotive horizontal member according to any one of 1 to 11, wherein the automotive horizontal member is a battery cover or a battery bottom protective cover. 13. The automotive horizontal member according to any one of 1 to 12, wherein the springback rate of the resin layer (P1) is 1.2 or more and 8.0 or less.

[0012] In the automotive horizontal member of the present invention, a resin layer (P1) and a thermal conductive layer (P2) are laminated together. According to equations (2) and (3), the thermal conductivity tc2 of the thermal conductive layer (P2) is more than 10 times greater than the thermal conductivity tc1 of the resin layer (P1) (10 < tc2 / tc1).

[0013] With this design, when the automotive horizontal member of the present invention is exposed to flames from the resin layer (P1) side, heat is conducted from the resin layer (P1) to the heat conduction layer (P2), and then dissipated into the air while spreading in the in-plane direction of the heat conduction layer (P1). As a result, fire resistance can be greatly improved compared to an automotive horizontal member made solely of the resin layer (P1).

[0014] A schematic diagram showing a test specimen undergoing a combustion test. A schematic diagram showing an example of a vehicle structure equipped with a battery bottom protective cover below the battery box, which is an example of using the horizontal member for automobiles of the present invention in a battery cover or battery tray. A graph showing the load-strain curve in a tensile test of a test specimen of Reference Example 1. A graph showing the load-strain curve in a tensile test of Reference Example 5. The upper mold is closed and pressing the metal plate. The metal plate alone is placed in the mold and being molded. The metal plate and molding material are laminated and molded as a single unit. The metal plate alone is placed in the mold and being molded. The metal plate and molding material are laminated and molded as a single unit. A plan view showing an example of a precursor for the heat conductive layer P2. A schematic diagram of an automobile horizontal member with a resin layer P1 and a heat conductive layer P2 laminated together. A schematic diagram showing how, after flame exposure, the resin layer P1 transitions to a solidified layer P3 and an expanded layer P4, resulting in the stacking of the heat conduction layer P2, solidified layer P3, and expanded layer P4. A side view photograph of an automotive horizontal member after flame exposure. A graph (Examples 1 and 2) showing the temperature of the surface on the heat conduction layer P2 side measured for 1800 seconds at a position 70 mm horizontally from the center of combustion, after the surface of the automotive horizontal member was exposed to a burner from the resin layer P1 side so that the flame surface reached 1000°C. A graph (Examples 1 and 2) showing the temperature of the surface on the heat conduction layer P2 side measured for 850 seconds at a position 70 mm horizontally from the center of combustion, after the surface of the automotive horizontal member was exposed to a burner from the resin layer P1 side so that the flame surface reached 1000°C. A graph (Examples 1 and 2, Comparative Example 1) showing the temperature of the surface on the heat conduction layer P2 side measured for 850 seconds at a position 70 mm horizontally from the center of combustion. A schematic diagram showing the heat conduction and heat dissipation when a combustion test is performed with a heat conduction layer P2. A schematic diagram showing the heat conduction and heat dissipation when a combustion test is conducted using only the resin layer P1, without the heat conduction layer P2.

[0015] The present invention will now be described in detail. Figure 9A is a schematic diagram of a horizontal member for an automobile according to this embodiment. As shown in Figure 9, the horizontal member for an automobile has a resin layer P1 and a heat conductive layer P2 laminated on the resin layer P1. The resin layer P1 contains reinforcing fibers with a weight-average fiber length of 5 mm to 100 mm and resin. The resin and reinforcing fibers used in the resin layer P1 and the heat conductive layer P2 will be described later.

[0016] In this specification, tc1, tc2, tc3, t1, t2, t3, and t4 are as follows: tc1: Thermal conductivity of resin layer P1 tc2: Thermal conductivity of heat conduction layer P2 tc3: Thermal conductivity in the thickness direction of the horizontal member for automobiles t1: Thickness of resin layer P1 t2: Thickness of heat conduction layer P2 t3: Thickness of solidified layer P3 t4: Thickness of expanded layer P4

[0017] [Various Thicknesses of Automotive Horizontal Members] 1. Thickness of Resin Layer P1 The thickness t1 of the resin layer P1 in the present invention is preferably 1.3 mm < t1 < 10.0 mm, as shown in formula (4). Formula (4) is preferably formula (4a), more preferably formula (4b), and even more preferably formula (4c). Formula (4a) is 1.4 mm < t1 < 8.0 mm, more preferably formula (4b) is 1.5 mm < t1 < 7.0 mm, and even more preferably formula (4c) is 1.5 mm < t1 < 6.0 mm. If t1 is 1.3 mm or more, there is sufficient margin for transition to the solidified layer P3 and the expanded layer P4 when exposed to flame. If t1 is 10.0 mm or less, the thickness of the automotive horizontal member can be reduced to make it lighter, and in the interior design of the automobile, the design space for the location where the automotive horizontal member is installed can be expanded.

[0018] 2. Thickness of the thermal conductive layer P2 The thickness t2 of the thermal conductive layer P2 in the present invention is preferably 0.005 mm < t2 < 1.0 mm, as shown in formula (5). Formula (5) is preferably formula (5a), more preferably formula (5b), and even more preferably formula (5c). Formula (5a) 0.01 mm < t2 < 0.8 mm Formula (5b) 0.02 mm < t2 < 0.7 mm Formula (5c) 0.03 mm < t2 < 0.6 mm The thermal conductive layer P2 is preferably a metal layer.

[0019] [Solidified and Expanded Layers After Combustion] 1. As shown in the schematic diagram 9B, it is preferable that a portion of the resin layer P1 expands when exposed to flame, forming a solidified layer P3 and an expanded layer P4. The formation of the expanded layer P4 is due to the softening of the thermoplastic resin when the resin layer P1 is exposed to flame, which causes springback of the reinforcing fibers. The resin layer P1 forms the expanded layer P4 sequentially from the flame-exposed side, and the solidified layer P3 transitions so that the original resin layer P1 remains. In other words, of the resin layer P1, the portion where the thermoplastic resin softens due to heating and springback of the reinforcing fibers occurs is the expanded layer P4, and the portion where springback has not occurred is the solidified layer P3.

[0020] In other words, when the surface of an automotive horizontal member is exposed to a flame from the resin layer P1 side with a burner so that the flame surface reaches 1000°C, and the automotive horizontal member is observed after 600 seconds, it is preferable that the resin layer P1 transitions into a solidified layer P3 and an expanded layer P4, and that the thickness t3 of the solidified layer P3 satisfies equation (6) and the thickness t4 of the expanded layer P4 satisfies equation (7) relative to the thickness t1 of the resin layer P1. Equation (6) t1 × 0.1 < t3 < t1 × 0.7 Equation (7) t1 × 0.3 × 1.05 < t4 < t1 × 0.9 × 8 If the automotive horizontal member ignites and burns after 600 seconds of exposure to a flame from the burner so that the flame surface reaches 1000°C, the flame should be extinguished after 600 seconds and then observed. The observation location should be the area that was directly exposed to the burner flame. Furthermore, even when a combustion test such as the UL 2596 BETR test is performed, where heat is applied instantaneously for a short period of time at the beginning, the solidified layer and the expanded layer can be observed.

[0021] 2. The solidification layer formula (6) refers to the range of thickness of the solidification layer, meaning that 600 seconds after the surface of the horizontal member for automobiles is flammed with a burner from the resin layer P1 side so that the flame surface reaches 1000°C, more than 10% and less than 70% of the thickness t1 of the resin layer P1 remains as a solidified layer. Formula (6) is preferably formula (6a), more preferably formula (6b), and even more preferably formula (6c). Formula (6a) t1 × 0.2 < t3 < t1 × 0.6 Formula (6b) t1 × 0.25 < t3 < t1 × 0.5 Formula (6c) t1 × 0.3 < t3 < t1 × 0.4 More specifically, the solidification layer t3 preferably satisfies the following formula (6d), and more preferably satisfies formula (6e). Formula (6d) 0.1 mm < t3 < 5 mm Formula (6e) 0.5 mm < t3 < 3 mm

[0022] 3. The expansion layer formula (7) refers to the range of thickness of the expansion layer, and means that 600 seconds after the surface of the horizontal member for automobiles is exposed to flame from the resin layer P1 side with a burner so that the flame surface reaches 1000°C, more than 30% and less than 90% of the thickness t1 of the resin layer P1 becomes the expansion layer, and that the portion of the thickness t1 of the resin layer P1 that is more than 30% and less than 90% expands in the thickness direction by more than 1.05 times and less than 8 times. Formula (7) is preferably formula (7a), more preferably formula (7b), and even more preferably formula (7c). Equation (7a) t1 × 0.4 × 1.05 < t4 < t1 × 0.8 × 8 Equation (7b) t1 × 0.5 × 1.05 < t4 < t1 × 0.75 × 8 Equation (7c) t1 × 0.6 × 1.05 < t4 < t1 × 0.7 × 8 More specifically, the expansion layer t4 preferably satisfies the following equation (6d), more preferably satisfies equation (6e), and even more preferably satisfies equation (6f). Equation (7d) 1 mm < t4 < 20 mm Equation (7e) 1.5 mm < t4 < 15 mm Equation (7f) 2 mm < t4 < 10 mm

[0023] The present invention provides an improved horizontal member for automobiles that enhances fire resistance during combustion. The inventors envision the following scheme: 1. The scheme envisioned by the inventors 1.1 Initial heating (The flame surface on the resin layer P1 is applied with a burner for 0 to 500 seconds so that it reaches 1000°C) (1) The resin layer P1 is heated and its temperature rises. The increased temperature is transferred to the heat conduction layer P2, and the heat dissipation effect from the heat conduction layer P2 suppresses the temperature rise of the resin layer P1. (2) The heat transferred to the heat conduction layer P2 is not only dissipated into the air but also conducted in the in-plane direction (XY direction in Figures 9A, 9B, 12A, and 12B). The length of the dashed arrow 1202 in Figure 12A indicates the in-plane heat conduction. The thermal conductivity in the in-plane direction is more than 10 times faster for the thermal conductivity tc2 of the heat conduction layer P2 than for the thermal conductivity tc1 of the resin layer P1 (Equation (1)). When explained schematically, the dashed arrow 1202 indicating heat conduction in Figure 12A (with heat conduction layer P2) is longer within the heat conduction layer P2 compared to the dashed arrow 1203 indicating heat conduction in Figure 12B (without heat conduction layer P2), indicating faster heat conduction in the in-plane direction. Therefore, compared to the case without heat conduction layer P2, the horizontal member for automobiles equipped with heat conduction layer P2 has a larger surface area that can dissipate heat into the air, and as a result, the amount of heat dissipated from the horizontal member for automobiles increases.

[0024] The heat dissipation process is shown by the solid arrows 1201 in Figures 12A and 12B. The number of arrows 1201 (heat dissipation) in Figure 12A (with the heat conductive layer P2) is greater than the number of arrows 1201 (heat dissipation) in Figure 12B (without the heat conductive layer P2).

[0025] 1.2 Mid-heating stage (500 seconds to 900 seconds after applying the burner flame so that the flame surface on the resin layer P1 side reaches 1000°C) As shown in Figure 9B, an expansion layer P4 begins to form from the flame surface on the resin layer P1 side due to the springback of the reinforcing fibers. This is because the thermoplastic resin that fixed the reinforcing fibers melts, releasing the residual stress in the reinforcing fibers in the resin layer P1. In the expansion layer P4 where springback has occurred, the gaps between the reinforcing fibers become larger, allowing air to flow into the interior. As a result, the thermal conductivity of the expansion layer P4 decreases. In other words, the role of the expansion layer P4 is to insulate the heat generated by the air barrier. On the other hand, the solidified layer P3, which is the part of the resin layer P1 where springback of the reinforcing fibers has not occurred, continues to transfer heat to the heat conduction layer P2. The heat conduction layer P2, which is in contact with the solidified layer P3, continues to dissipate some of the heat applied to the horizontal member of the automobile. Because heat is moderately dissipated from the horizontal member of the automobile, even if the resin layer P1 continues to heat up, it is insulated by the expansion layer P4 and heat is continuously dissipated by the heat conduction layer P2, thus preventing the occurrence of drape down, where the molten thermoplastic resin sags under its own weight.

[0026] 1.3 Final stages of heating (after 900 seconds and before 1800 seconds have passed since the burner was applied so that the flame surface on the resin layer P1 side reached 1000°C) The solidified layer P3 becomes minimal, and the insulating effect of the expanded layer P2 increases. Therefore, even if heat continues to be applied to the expanded layer P2, the heat dissipation from the horizontal member of the automobile decreases.

[0027] 2. Temperature drop during combustion The surface of the horizontal automotive member on the resin layer P1 side is exposed to a flame from a burner so that the flame surface reaches 1000°C. The temperature of the surface on the heat conduction layer P2 side is measured at a position 70 mm away from the center of the flame contact point. Preferably, the curve plotted to obtain the temperature has a region where the slope is negative between 900 seconds and 1800 seconds after the start of flame contact. There are no particular limitations on the method of measuring the temperature of the surface on the heat conduction layer P2 side; a contact thermometer or a non-contact thermometer may be used.

[0028] In the curve plotting the temperature on the heat conduction layer P2 side at a position 70 mm away from the center of the flame contact point, the presence of a region where the slope is negative between 900 seconds and 1800 seconds after the start of flame contact means that, in "1.3 Final stages of heating" above, there are times when the temperature of the surface on the heat conduction layer P2 side decreases at a position 70 mm away from the heating point.

[0029] [Thermal Conductivity] 1. Formula (1) The thermal conductivity tc1 of the resin layer P1 of the present invention and the thermal conductivity tc2 of the thermal conductivity layer P2 satisfy formula (1). Formula (1) 10 < tc2 / tc1 Formula (1) is preferably formula (1a), more preferably formula (1b), and even more preferably formula (1c). Formula (1a) 10 < tc2 / tc1 < 1500 Formula (1b) 100 < tc2 / tc1 < 1300 Formula (1c) 250 < tc2 / tc1 < 1000 By satisfying formula (1), when an automotive horizontal member is exposed to a flame, the heat dissipation that was insufficient with the resin layer P1 alone can be improved by the thermal conductivity layer P2, which conducts heat in the in-plane direction, thereby expanding the heat dissipation area.

[0030] 2. tc1 The thermal conductivity tc1 of the resin layer P1 of the present invention satisfies formula (2). Formula (2) 0.01 W / (m·K) < tc1 < 10 W / (m·K) Formula (2) is preferably formula (2a), more preferably formula (2b), and even more preferably formula (2c). Formula (2a) 0.05 W / (m·K) < tc1 < 5 W / (m·K) Formula (2b) 0.1 W / (m·K) < tc1 < 3 W / (m·K) Formula (2c) 0.2 W / (m·K) < tc1 < 0.6 W / (m·K)

[0031] 3. tc2 The thermal conductivity tc2 of the thermal conductive layer P2 of the present invention satisfies formula (3). Formula (3) 100 W / (m·K) < tc2 < 350 W / (m·K) Formula (3) is preferably formula (3a), and more preferably formula (3b). Formula (3a) 150 W / (m·K) < tc1 < 300 W / (m·K) Formula (3b) 200 W / (m·K) < tc1 < 250 W / (m·K)

[0032] 4. Formula (8) Preferably, the thermal conductivity tc3 in the thickness direction of the horizontal member for automobiles of the present invention and the thermal conductivity tc1 of the resin layer P1 satisfy formula (8). Formula (8) 0.8 < tc3 / tc1 < 1.2 Formula (8) is more preferably formula (8a). Formula (8a) 0.85 < tc3 / tc1 < 1.1 Satisfying formula (8) means that the thickness of the resin layer P1 is sufficient and the thickness of the thermal conductivity layer P2 is thin. This is intended to achieve both moldability and fire resistance.

[0033] 5. tc3 The thermal conductivity tc3 in the thickness direction of the horizontal member for automobiles of the present invention preferably satisfies formula (9). Formula (9) is preferably formula (9a), more preferably formula (9b), and even more preferably formula (9c). Formula (9) 0.1 W / (m·K) < tc3 < 10 W / (m·K) Formula (9a) 0.1 W / (m·K) < tc3 < 5 W / (m·K) Formula (9b) 0.1 W / (m·K) < tc3 < 3 W / (m·K) Formula (9c) 0.2 W / (m·K) < tc3 < 0.6 W / (m·K)

[0034] The reinforcing fibers, resin, and other components used in the resin layer P1 are described below. [Reinforcing Fibers] In this specification, the reinforcing fibers are preferably at least one selected from the group consisting of carbon fibers, aramid fibers, and glass fibers. More preferably, the reinforcing fibers are carbon fibers or glass fibers.

[0035] [Carbon Fibers] 1. General Information on Carbon Fibers As carbon fibers used in the resin layer P1, polyacrylonitrile (PAN) carbon fibers, petroleum / coal pitch carbon fibers, rayon carbon fibers, cellulose carbon fibers, lignin carbon fibers, and phenolic carbon fibers are generally known, but in the present invention, any of these carbon fibers can be suitably used. Among these, in the present invention, it is preferable to use polyacrylonitrile (PAN) carbon fibers because they have excellent tensile strength. As a PAN carbon fiber, for example, Teijin Limited's carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) can be used.

[0036] 2. Carbon fibers used in the resin layer P1 of the carbon fiber sizing agent may have a sizing agent attached to its surface. When using carbon fibers with a sizing agent attached, the type of sizing agent can be appropriately selected according to the type of carbon fiber and the type of resin used in the resin layer P1, and is not particularly limited.

[0037] [Glass Fibers] This section describes the case where glass fibers are used as reinforcing fibers in the resin layer P1. 1. Glass Fibers in General Any glass fiber that is generally referred to as glass fiber may be used in the resin layer P1. There are no particular limitations on the glass composition, such as A glass, C glass, E glass, etc., and TiO may be used depending on the case. ２ SO ３ , P ２ O ５ It may also contain components such as the above. As for glass fibers, for example, RV P204-4800TEX manufactured by Owens Corning can be used.

[0038] 2. Glass fibers used in the resin layer P1 of the glass fiber sizing agent may have a sizing agent attached to its surface. When using glass fibers with a sizing agent attached, the type of sizing agent can be appropriately selected according to the type of glass fiber and the type of resin, and is not particularly limited. Preferably, glass fibers that have been pre-treated with conventionally known coupling agents such as organosilane compounds, organotitanium compounds, organoborane compounds, and epoxy compounds can be used.

[0039] 3. To prepare the resin layer P1, it is preferable to mix single-end roving glass fibers GFs and multi-end roving glass fibers GFm in a volume ratio of GFm:GFs of 50:50 to 90:10. If the proportion of GFm is 50% or more, the work rate can be easily kept below the upper limit. If the proportion of GFm is 90% or less, the work rate can be kept below the lower limit.

[0040] Multi-end roving refers to roving where the ends of the glass strands are not aligned. In multi-end roving, the glass fibers have multiple ends. Single-end roving refers to roving where the ends of the glass strands are aligned to a single point. In single-end roving, the glass fibers have only one end.

[0041] [Dispersed in the in-plane direction] It is preferable that the reinforcing fibers contained in the resin layer P1 are dispersed in the in-plane direction. Furthermore, it is preferable that the resin layer P1 of the present invention be manufactured by cold pressing a molding material containing reinforcing fibers and a thermoplastic resin. In this case, it is even more preferable that the reinforcing fibers contained in the molding material are dispersed in the in-plane direction. Dispersion of reinforcing fibers in the in-plane direction means that the fiber axes of the reinforcing fibers are dispersed so as to be oriented in the in-plane direction. It is preferable that the angle that the fiber axes of the reinforcing fibers make with the in-plane direction is 45° or less.

[0042] 1. The molding material for manufacturing the in-plane oriented resin layer P1 is preferably a plate-shaped material. The in-plane direction refers to an undefined direction of parallel planes perpendicular to the thickness direction of the molding material. 2. The reinforcing fibers are preferably randomly dispersed in a two-dimensional direction in the in-plane direction. When the molding material is press-molded without flowing (non-flow molding), the shape of the reinforcing fibers is largely maintained before and after molding. In the case of non-flow molding, it is preferable to orient the reinforcing fibers contained in the molding material randomly in two dimensions so that the reinforcing fibers contained in the molded resin layer P1 (molded body) are similarly dispersed randomly in two dimensions in the in-plane direction.

[0043] Here, "randomly dispersed in two dimensions" means that the reinforcing fibers are oriented in a disordered manner within the in-plane direction of the molding material, rather than in a specific direction such as one direction, and are arranged within the sheet surface without exhibiting a specific direction overall. The molding material (or resin layer P1) obtained using these two-dimensionally randomly dispersed discontinuous fibers is a substantially isotropic molding material (or resin layer P1) that does not have anisotropy within the plane.

[0044] The degree of two-dimensional random orientation is evaluated by determining the ratio of the tensile moduli in two mutually orthogonal directions. If the ratio (Eδ) obtained by dividing the larger of the measured tensile moduli in any direction of the molding material (or resin layer P1) and in a direction orthogonal thereto by the smaller value is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less, then the reinforcing fibers can be evaluated as being dispersed randomly in two dimensions. If the resin layer P1 includes a curved surface, a good method for evaluating the two-dimensional random dispersion in the in-plane direction is to heat it above the softening temperature to return it to a flat plate shape and then solidify it. After that, by cutting out a test piece and determining the tensile modulus, the random dispersion state in the two-dimensional direction can be confirmed.

[0045] [Fiber Length of Reinforcement Fibers] The resin layer P1 contains reinforcement fibers with a weight-average fiber length of 5 mm to 100 mm. Since the weight-average fiber length of the molding material and the resin layer P1 (molded body) does not change before and after molding, the weight-average fiber length Lw of the reinforcement fibers contained in the molding material can be determined by examining the weight-average fiber length of the reinforcement fibers contained in the resin layer P1 (molded body).

[0046] The lower limit of the weight-average fiber length of the reinforcing fibers is preferably 7 mm or more, and more preferably 10 mm or more. Conversely, the upper limit of the weight-average fiber length is preferably 80 mm or less, and more preferably 70 mm or less. When the weight-average fiber length is 5 mm or more, the mechanical strength of the resulting resin layer P1 is less likely to decrease, which is preferable. When the weight-average fiber length is 100 mm or less, the fluidity of the material is less likely to decrease when the molding material is manufactured by press molding, and it is easier to create the resin layer P1 in the desired shape. The preferred weight-average fiber length range for the reinforcing fibers is 5 mm or more and 80 mm or less, and more preferably 10 mm or more and 60 mm or less.

[0047] [Resin layer P1: Number average fiber length Ln and weight average fiber length Lw] Generally, if the fiber length of each reinforcing fiber is Li, the number average fiber length Ln and the weight average fiber length Lw can be calculated using the following equations (X) and (Y). Note that the units of the number average fiber length Ln and the weight average fiber length Lw are mm.

[0048] Here, "I" indicates the number of reinforced fibers measured.

[0049] When the fiber length is constant, the number-average fiber length and the weight-average fiber length will be the same value. Reinforcement fibers from automotive horizontal members can be extracted, for example, by heat treatment at approximately 500°C for 1 hour and removing the resin in the furnace. The average fiber length can be determined, for example, by measuring the fiber length of 100 fibers randomly extracted from the resin layer P1 to the nearest 1 mm using a caliper or the like, and calculating it based on formula (X).

[0050] If short fibers that cannot be measured with calipers are present, the resin is removed, and the resulting reinforced fibers are placed in water containing a surfactant and thoroughly stirred using ultrasonic vibration. A random sample of the stirred dispersion is taken using a measuring spoon to obtain an evaluation sample, and the length of 3000 fibers is measured using a Nireco Luzex AP image analysis device. Using the measured fiber lengths, the number-average fiber length Ln and the weight-average fiber length Lw can be determined in the same manner as the above-mentioned equations (X) and (Y).

[0051] [Resin layer P1: Volume ratio of reinforcing fibers] The volume ratio of reinforcing fibers (Vf) contained in the resin layer P1 can be calculated using the following formula (10). Volume ratio of reinforcing fibers (Vf) = 100 × volume of reinforcing fibers / (volume of reinforcing fibers + volume of resin) Formula (10) There are no particular limitations on the volume ratio of reinforcing fibers, but the volume ratio of reinforcing fibers (Vf) is preferably 10 to 60 Vol%, more preferably 20 to 50 Vol%, and even more preferably 25 to 45 Vol%.

[0052] [Analysis of Reinforcement Fiber Volume Ratio (Vf)] There are no limitations to the analysis of the reinforcement fiber volume ratio, but it is recommended to measure it as follows. Cut a sample from the resin layer P1 of an automotive horizontal member, burn off the thermoplastic resin in a furnace at 500°C for 1 hour, and calculate the mass of the reinforcement fiber and resin by weighing the sample before and after treatment. Next, calculate the volume of the reinforcement fiber by dividing the mass of the reinforcement fiber by the density of the reinforcement fiber, and calculate the volume of the thermoplastic resin by dividing the mass of the thermoplastic resin by the density of the resin. Next, calculate the ratio Vf of the volume of the reinforcement fiber to the total volume of the reinforcement fiber and thermoplastic resin.

[0053] [Resin layer P1: Flame retardant] 1. The resin layer P1 of the present invention preferably contains a flame retardant. The flame retardant is not particularly limited and examples include phosphorus-based flame retardants, bromine-based flame retardants, antimony-based flame retardants, etc. Among these, phosphorus-based flame retardants are preferred from the viewpoint of improving flame resistance. Furthermore, in a classification that focuses on the mechanism of action of the flame retardant, it is preferable that the flame retardant be an intomessecent flame retardant from the viewpoint of improving flame resistance.

[0054] 2. Phosphorus-based flame retardants Phosphorus-based flame retardants are phosphorus compounds, that is, compounds that contain phosphorus atoms in their molecules. Phosphorus-based flame retardants exert their flame-retardant effect by forming char during the combustion of resin compositions.

[0055] The phosphorus-based flame retardant may be any known substance, such as (poly)phosphate or (poly)phosphate ester. Here, "(poly)phosphate" refers to a phosphate or polyphosphate, and "(poly)phosphate ester" refers to a phosphate ester or polyphosphate ester. It is preferable that the phosphorus-based flame retardant is solid at 80°C.

[0056] As a phosphorus-based flame retardant, (poly)phosphates are preferred in terms of flame retardancy. Examples of (poly)phosphates include ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, melamine orphosphate, calcium phosphate, and magnesium phosphate.

[0057] Furthermore, compounds in which melamine or piperazine is replaced with other nitrogen compounds in the above examples can also be used. Examples of other nitrogen compounds include N,N,N',N'-tetramethyldiaminomethane, ethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, and tetramethyl Diadiamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetoguanamine, benzoguanamine, acrylicguanamine, 2,4-diamino-6-nonyl-1,3,5-triamine Zin, 2,4-diamino-6-hydroxy-1,3,5-triazine, 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-mercapto-1, Examples include 3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammeline, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, melamine pyrophosphate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, and 1,3-hexylenedimelamine. These (poly)phosphates may be used individually or in combination of two or more.

[0058] Examples of commercially available phosphorus-based flame retardants include ADEKA® FP-2100J, FP-2200, FP-2500S (manufactured by ADEKA Corporation), ADEKA® FP-2100 JC, and Exolit® AP462 and Exolit OP1230 manufactured by Clariant.

[0059] 3. Intomessent Flame Retardants Intomessent flame retardants are flame retardants that suppress the combustion of materials by forming a surface expansion layer (intumescent) that prevents radiant heat from the combustion source and the diffusion of combustion gases and smoke from the burning material to the outside.

[0060] Intomessent flame retardants cause the resin composition to form a surface expansion layer (intomescent), which is a foamed char, during combustion. The formation of this surface expansion layer suppresses the diffusion of decomposition products and heat transfer, resulting in excellent flame retardancy. Examples of intomessent flame retardants include salts of (poly)phosphate and nitrogen compounds, specifically ammonium salts and amine salts of (poly)phosphate.

[0061] 4. Brominated Flame Retardants Examples of brominated flame retardants include decabromodiphenyl ether, tetrabromobisphenol A, tetrabromobisphenol S, 1,2-bis(2',3',4',5',6'-pentabromophenyl)ethane, 1,2-bis(2,4,6-tribromophenoxy)ethane, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, 2,6-dibromophenol, and 2,4-dibromophenoxy. Examples include polystyrene, brominated polystyrene, ethylenebistetrabromophthalimide, hexabromocyclododecane, hexabromobenzene, pentabromobenzyl acrylate, 2,2-bis[4'(2'',3''-dibromopropoxy)-3',5'-dibromophenyl]-propane, bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone, and tris(2,3-dibromopropyl) isocyanurate.

[0062] 5. Antimony-based flame retardants Examples of antimony-based flame retardants include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium pyroantimonate, antimony trichloride, antimony trisulfide, antimony oxychloride, antimony perchloropentane dichloride, and potassium antimonate, with antimony trioxide and antimony pentoxide being particularly preferred.

[0063] 6. Flame Retardant Scheme Figure 10 shows the temperature of the heat conduction layer P2 side surface at a distance of 70 mm from the heating position for 1800 seconds during combustion tests of the automotive horizontal members of Examples 1 and 2 described later. Figure 11 shows the temperature of the heat conduction layer P2 side surface at a distance of 70 mm from the heating position for 850 seconds during combustion tests of the automotive horizontal members of Examples 1, 2 and Comparative Example 1 described later. In Example 1, the temperature of the heat conduction layer P2 side surface at a distance of 70 mm from the heating position rapidly rises to 150°C approximately 250 seconds after the start of the experiment (start of flame contact with resin layer P1), but then gradually burns, with the maximum surface temperature reaching just under 180°C. This is because the combustion components are completely burned off in about 250 seconds, and the carbonization of the flame retardant components begins. When an intomessecent flame retardant is used, the carbonization of the intomessecent flame retardant is accelerated as it expands.

[0064] [Resin layer P1: Flame retardant content] The flame retardant content in the resin layer P1 is preferably 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of resin. More preferably, it is in the range of 1 part by mass or more and 30 parts by mass or less, and even more preferably, in the range of 5 parts by mass or more and 25 parts by mass. If it is 1 part by mass or more, good flame retardancy can be imparted to the resin layer P1 and good flame shielding properties can be obtained. On the other hand, if the flame retardant is 50 parts by mass or less, the moldability is further improved.

[0065] [Resin Layer P1: Dispersant] 1. Overview The dispersant does not need to be particularly limited as long as it can disperse the flame retardant in the resin, but polymer dispersants can be suitably used in terms of compatibility with the resin. Preferably, a dispersant that can disperse the flame retardant in the polypropylene resin can be used. As for polymer dispersants, polymer dispersants having functional groups are preferred, and from the viewpoint of dispersion stability, polymer dispersants having functional groups such as carboxyl groups, phosphate groups, sulfonic acid groups, primary, secondary or tertiary amino groups, quaternary ammonium bases, pyridine, pyrimidine, pyrazine, and other nitrogen-containing heterocycle-derived groups are preferred.

[0066] In the present invention, polymeric dispersants having carboxyl groups are preferred, and in particular, when using phosphorus-based flame retardants suitable as flame retardants, copolymers of α-olefins and unsaturated carboxylic acids are preferred. By using such dispersants, the dispersibility of phosphorus-based flame retardants can be improved, and the content of the flame retardant can be reduced.

[0067] 2. Necessity of Dispersant: Dispersant does not need to be added to the resin layer P1 in this invention. It is not necessarily required if flame retardancy can be ensured.

[0068] [Resin layer P1: Other agents] The resin layer P1 of the present invention may contain additives such as various fibrous or non-fibrous fillers of organic or inorganic fibers, UV resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, and surfactants, to the extent that the objectives of the present invention are not impaired.

[0069] [Method for Manufacturing Resin Layer P1] The molding material is the material used to create the resin layer P1, and the molding material is preferably in the form of a flat plate. On the other hand, the resin layer P1 is a molded body and has a defined shape. 1. Cold Press (Molding) Method As a molding method for manufacturing the resin layer P1 (molded body) of the present invention, press molding (sometimes called compression molding) is used, and in particular, press molding using cold press is preferred. In the cold press molding method, for example, a molding material heated to a first predetermined temperature is placed into a mold set to a second predetermined temperature, and then pressurized and cooled.

[0070] Specifically, if the thermoplastic resin constituting the molding material is crystalline, the first predetermined temperature is above the melting point of the thermoplastic resin, and the second predetermined temperature is below the melting point. If the thermoplastic resin is amorphous, the first predetermined temperature is above the glass transition temperature of the thermoplastic resin, and the second predetermined temperature is below the glass transition temperature. In other words, the cold press molding method includes at least the following steps A-1) to A-2).

[0071] Step A-1) A step of heating the molding material to a temperature above the melting point of the thermoplastic resin or below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is crystalline, or above the glass transition temperature or below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous. Step A-2) A step of placing the molding material heated in Step A-1) into a mold that has been temperature-controlled to below the melting point of the thermoplastic resin if the thermoplastic resin is crystalline, or below the glass transition temperature if the thermoplastic resin is amorphous, and applying pressure. By performing these steps, the molding of the molding material can be completed. The above steps must be performed in the order described above, but other steps may be included between each step. Other steps include, for example, a shaping step before Step A-2) in which a different shaping mold is used in addition to the mold used in Step A-2) to pre-shape the material to the shape of the mold cavity.

[0072] 2. Hot Pressing Method The hot pressing method involves, for example, placing a molding material into a mold, applying pressure while raising the temperature of the mold to a first predetermined temperature, and then cooling the mold to a second predetermined temperature. Specifically, if the thermoplastic resin constituting the molding material is crystalline, the first predetermined temperature is above the melting point of the thermoplastic resin, and the second predetermined temperature is below the melting point. If the thermoplastic resin constituting the molding material is amorphous, the first predetermined temperature is above the glass transition temperature of the thermoplastic resin, and the second predetermined temperature is below the glass transition temperature.

[0073] The hot press molding method preferably includes at least the following steps B-1) to B-4): B-1) A step of placing the molding material in the mold (lower mold). B-2) A step of heating and pressurizing the mold to a temperature above the melting point of the thermoplastic resin but below the thermal decomposition temperature if the thermoplastic resin is crystalline, or to a temperature above the glass transition temperature of the thermoplastic resin but below the thermal decomposition temperature if the thermoplastic resin is amorphous (first press step). B-3) A step of pressurizing in one or more stages, such that the pressure in the final stage is 1.2 times or more but 100 times or less the pressure in the first press step (second press step). B-4) A step of adjusting the mold temperature to below the melting point if the thermoplastic resin is crystalline, or below the glass transition temperature if the thermoplastic resin is amorphous. By performing these steps, the molding of the molding material can be completed.

[0074] 3. Common aspects of cold press molding and hot press molding Steps A-2) and B-3) are steps in which pressure is applied to the molding material to obtain a molded body of the desired shape. There are no particular limitations on the molding pressure at this time, but it is preferable to keep it as low as possible within the range in which the desired molded body shape can be obtained. Specifically, it is preferable to have a molding pressure of less than 30 MPa relative to the projected area of ​​the mold cavity, more preferably 20 MPa or less, and even more preferably 10 MPa or less. When the molding pressure is less than 30 MPa, it is preferable because it does not require capital investment or maintenance costs for the press machine. Also, naturally, various steps may be inserted between the above steps during compression molding, for example, vacuum compression molding, which is performed while compressing the material under vacuum, may be used.

[0075] [Resin Layer P1: Springback] 1. Springback of Molding Material In order to perform cold press molding using molding material, it is necessary to preheat and heat the molding material to a predetermined temperature to soften and melt it. When the thermoplastic resin becomes plastic during preheating of molding material containing reinforcing fibers with a weight-average fiber length of 5 mm to 100 mm (especially when it contains a mat state in which the reinforcing fibers are deposited), the preheated molding material expands due to the springback of the reinforcing fibers, and the bulk density of the molding material changes. When the bulk density changes during preheating, the molding material becomes porous, the surface area increases, and air flows into the interior of the molding material, promoting the thermal decomposition of the thermoplastic resin. The springback rate tends to increase when the reinforcing fiber bundles contained in the molding material are highly open (single-fiber rich) or when the fiber length is long. Here, the springback rate is the value obtained by dividing the plate thickness of the molding material after preheating by the plate thickness of the molding material before preheating.

[0076] In this invention, the springback rate of the molding material is 1.05 or more and 8.0 or less, preferably 1.2 or more and 8.0 or less. If the springback rate of the molding material is 8.0 or less, it is possible to prevent the horizontal member of an automobile from expanding too much when the resin layer P1 formed from the molding material is burned. Conversely, if the springback rate is 1.05 or more, the resin layer P1 made from the molding material expands easily when heated, thus providing an insulating effect.

[0077] A preferred springback ratio for the molding material is 3.0 to 8.0, a more preferred springback ratio for the molding material is 4.0 to 7.0, and an even more preferred springback ratio is 4.0 to 6.0.

[0078] 2. Springback of Resin Layer P1 The resin layer P1 (molded body) of the present invention, like the molding material, has a springback rate of 1.05 to 8.0, preferably 1.2 to 8.0. A preferred springback rate for the resin layer P1 is 3.0 to 8.0, a more preferred springback rate for the resin layer P1 is 4.0 to 7.0, and an even more preferred springback rate is 4.0 to 6.0. If the springback rate of the resin layer P1 is 1.2 or higher, the resin layer P1 tends to expand when heated, making it easier to obtain a heat insulating effect.

[0079] [Thermal Conductive Layer P2: Type] The thermal conductive layer P2 in the present invention is not particularly limited, and a filler with high thermal conductivity may be mixed into the resin, or a metal may be used as a layer. There is no particular limit to the type of thermal conductive layer P2, but examples of metallic materials that satisfy formula (3) include pure aluminum (Al); aluminum alloys containing magnesium (Mg), copper (Cu), zinc (Zn), silicon (Si), manganese (Mn), etc.; pure copper (Cu); copper alloys containing nickel (Ni), tin (Sn), zinc (Zn), aluminum (Al), lead (Pb), phosphorus (P), etc.; pure magnesium; magnesium alloys containing aluminum (Al), zinc (Zn), manganese (Mn), zirconium (Zr), etc.; and conductive carbon such as graphite foil. Pure aluminum, aluminum alloys, pure copper, and copper alloys are particularly preferred.

[0080] [Lamination Method (Manufacturing Method) of Thermal Conductive Layer P2] There are no particular limitations on the lamination method of the thermal conductive layer P2, but the lamination method when the thermal conductive layer P2 is a metal layer will be described below. 1. The horizontal member for automobiles, in which the resin layer P1 and the thermal conductive layer P2 (metal layer) are laminated, may be an integrally molded body. Here, an integrally molded body is one in which the resin layer P1 and the thermal conductive layer P2 are integrally molded. Integral molding means that the resin layer P1 and the thermal conductive layer P2 are molded continuously without seams, and are not formed by joining separate parts. Such an integrally molded body can be realized by creating the horizontal member for automobiles in a single molding, and can preferably be realized by press molding. By creating the horizontal member for automobiles by integral molding, separate parts can be processed into one horizontal member for automobiles, making it possible to reduce the unit cost of parts. In addition, the number of assembly processes is reduced, and inventory costs can also be reduced due to the reduction in the number of parts. Integral molding is sometimes called commolding.

[0081] When manufacturing an automotive horizontal member by integral molding using a molding material that will become a resin layer P1 and a metal plate (precursor of the heat conductive layer P2) that will become a heat conductive layer P2, it is preferable that the metal layer which is the heat conductive layer P2 has a fold pattern with a pitch of 1 mm or more and less than 50 mm, and it is more preferable that the metal layer is provided with an uneven shape with a pitch of 1 mm or more and less than 50 mm by embossing.

[0082] 1.1 Advantages of integral molding 1.1.1 Challenges when integral molding is not used When a heat conductive layer P2 is obtained by shaping a metal sheet separately without using integral molding, the corners of the metal sheet tend to tear due to the irregularities of the mold (irregularities for shaping the metal sheet). At the corners, the cause of tearing is that the metal sheet stretches more than the elongation at break of the metal sheet (e.g., aluminum foil). Figure 5 is a cross-sectional view showing the state of press molding of a metal sheet 502. The area of ​​the metal sheet 502 that is prone to tearing during press molding is indicated by reference numeral 501 in Figure 5. In order to improve yield, conventionally, it was necessary to reinforce the area shown by 501 in Figure 5 by applying cushioning or reinforcing material such as gummed tape to prevent tearing. In addition, not only the corners as shown by 501 in Figure 5, but also when deep drawing is attempted in the metal sheet 502, that area tends to wrinkle. Alternatively, it was necessary to devise a design for the metal layer that softens the sharpness of the corners.

[0083] 1.2. Effects of integral molding (i) On the other hand, when the resin layer P1 and the heat conductive layer P2 (metal layer) are integrally molded, the role of the cushioning material can be replaced by the molding material that becomes the resin layer P1. This is a synergistic effect of integral molding of the heat conductive layer P2 (preferably an embossed metal layer) and the molding material that becomes the resin layer P1, so that the corners of the mold do not come into contact with the metal plate and it is less likely to tear. For example, when molding only the metal plate 502 without laminating the molding material that becomes the resin layer P1 as shown in Figure 6A, it is necessary to provide a gentle curve at the corner α of the mold so that the corner α does not tear the metal plate 502. On the other hand, as shown in Figure 6B, when the molding material 601 that will become the resin layer P1 is placed in the lower mold and the metal plate 502 is laminated on top of the molding material 601 that will become the resin layer P1 to integrally mold the metal plate 502 and the molding material 601 that will become the resin layer P1, the molding material 601 that will become the resin layer P1 acts as a buffer, so the metal plate 502 is less likely to tear, and there is no need to provide a gentle curve at the corner β of the lower mold. The same can be said for Figures 7A and 7B. For example, as shown in Figure 7A, when molding is done with only the metal plate 502 without laminating the molding material that will become the resin layer P1, it is necessary to provide a gentle curve at the corner γ of the upper mold so that the corner γ does not tear the metal plate 502. On the other hand, when the metal plate 502 is placed in the lower mold as shown in Figure 7B, and the molding material 601 that will become the resin layer P1 is laminated on top of the metal plate 502 to integrally mold the metal plate 502 and the molding material 601 that will become the resin layer P1, the molding material 601 that will become the resin layer P1 acts as a buffer, so the metal plate 502 is less likely to tear, and there is no need to provide a gentle curve at the corner δ of the upper mold.

[0084] 1.3. Effects of integral molding (ii) When using cold press molding, as shown in Figure 7B, if a metal plate 502 is placed in the lower mold and the molding material 601 that will become the resin layer P1 is laminated so as to be in contact with the upper mold, the molding material 601 that will become the resin layer P1 is not cooled to the mold temperature until just before it comes into contact with the upper mold. Therefore, it becomes easier to add ribs and bosses to the resin layer P1, and the design quality is also improved.

[0085] 1.4. Effects of integral molding (iii) The heat conduction layer P2 is embedded in the automotive horizontal member (integrally molded body), and it is preferable that the surface of the integrally molded body and the surface of the heat conduction layer P2 coincide. In this case, there is no step at the interface between the automotive horizontal member and the heat conduction layer P2, resulting in a flat shape. The interface may coincide with the top surface or the vertical surface of the automotive horizontal member. Since the end of the heat conduction layer P2 is embedded with the resin of the molding material that becomes the resin layer P1 during integral molding, chipping of the end of the heat conduction layer P2 can also be reduced.

[0086] 1.5. The automotive horizontal member of the present invention is preferably manufactured by laminating a molding material containing reinforcing fibers and a thermoplastic resin with a precursor of the heat conductive layer P2, and press molding using upper and lower molds. In this case, it is preferable to manufacture the automotive horizontal member by going through steps C1 to C2. Step C1: Prepare the precursor of the heat conductive layer P2 and provide an uneven shape with a pitch of 1 mm or more and less than 50 mm by embossing. Step C2: Put the precursor of the heat conductive layer P2 and the molding material into the lower mold, close the upper mold and press mold so that the precursor of the heat conductive layer P2 becomes the heat conductive layer P2 and the molding material becomes the resin layer P1. As a method of press molding (sometimes called compression molding) by putting the precursor of the heat conductive layer P2 and the molding material into a mold, hot press molding and cold press molding methods can be used.

[0087] 2. Integral Molding Using an Assembly of Metal Strips The present invention provides an automotive horizontal member that is an integrally molded body having a resin layer P1 and a heat conductive layer P2, wherein the heat conductive layer P2 is a layer containing an assembly of metal strips and a second thermoplastic resin, and the assembly of metal strips preferably consists of a plurality of metal strips dispersed in the plane of the heat conductive layer P2.

[0088] In this case, the integrally molded body is preferably manufactured by laminating a molding material containing reinforcing fibers and thermoplastic resin with a precursor of the heat conduction layer P2, and then press-molding it using upper and lower molds. As a method of press-molding (sometimes called compression molding) by introducing the molding material and the precursor of the heat conduction layer P2 into a mold, hot press molding or cold press molding methods can be used. More specifically, the molding material and the precursor of the heat conduction layer P2 are heated, the heated molding material and the precursor of the heat conduction layer P2 are stacked on top of each other, and the integrally molded body is manufactured by simultaneously pressing them in the mold.

[0089] Furthermore, the precursor of the heat conductive layer P2 in this case is preferably a layer containing an aggregate of metal strips 802 and a second thermoplastic resin (not shown), as shown in Figure 8, and the aggregate of metal strips 802 preferably shields at least one of an electric field or a magnetic field. The metal strips 802 are dispersed inside the precursor of the heat conductive layer P2 (precursor 801 of the heat conductive layer P2) to form an aggregate.

[0090] 2.1 Advantages of using a metal strip assembly during molding 2.1.1. Challenges when not using a metal strip assembly When a metal sheet is formed separately from the molding material without using a metal strip assembly, as described above, the corners of the metal sheet tend to break due to the irregularities of the molding die.

[0091] 2.2 Effects of Metal Strip Assembly (i) On the other hand, when integral molding is performed using a metal strip assembly, the precursor of the heat conductive layer P2 is less likely to tear even if it comes into contact with the corner of the mold, and there is no need to provide a soft curve at the corner of the mold.

[0092] 2.3. Effects of Metal Strip Assembly (ii) When using cold press molding, if the precursor of the heat conductive layer P2 is placed in the lower mold and the molding material is laminated so as to come into contact with the upper mold, the molding material is not cooled to the mold temperature until just before it comes into contact with the upper mold. Therefore, it becomes easier to impart ribs and bosses to the resin layer P1, and the design quality is also improved.

[0093] 2.4. Effects of Metal Strip Assembly (iii) Furthermore, when using a metal strip assembly as a thermal conductive layer P2, it is preferable that the precursor of the thermal conductive layer P2 contains a second thermoplastic resin. The inclusion of the second thermoplastic resin makes it easier to easily impart ribs, bosses, etc., to the thermal conductive layer P2 when integrally molding the molding material and the precursor of the thermal conductive layer P2. If only metal plates are provided as separate parts, it is not possible to impart complex shapes such as ribs, bosses, etc., to the thermal conductive layer P2.

[0094] 2.5. Effects of the Metal Strip Assembly (iv) The heat conduction layer P2 is embedded in the automotive horizontal member (integrally molded body), and it is preferable that the surface of the integrated molded body and the surface of the heat conduction layer P2 coincide. In this case, there is no step at the interface between the automotive horizontal member and the heat conduction layer P2, resulting in a flat shape. The interface coincidence may be on the top surface or the vertical surface of the automotive horizontal member. Since the ends of the heat conduction layer P2 are embedded in the resin of the resin layer P1 during integral molding, chipping of the ends of the heat conduction layer P2 can also be reduced.

[0095] 2.6 Thermal Conductive Layer P2: Size of the Metal Strip The metal strip is preferably 1 mm to 40 mm wide, 1 mm to 100 mm long, and 100 μm thick or less. A width of 1 mm or more makes slitting easier. The metal strip is more preferably 1 mm to 40 mm wide, 1 mm to 40 mm long, and 100 μm thick or less.

[0096] The width of the metal strip is more preferably 2 mm to 20 mm, even more preferably 2 mm to 7 mm, and even more preferably 2 mm to 5 mm. The length of the metal strip is more preferably 2 mm to 20 mm, even more preferably 2 mm to 7 mm, and even more preferably 2 mm to 5 mm. The thickness of the metal strip is more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 30 μm or less. The lower limit of the thickness of the metal strip is preferably 12 μm or more, and more preferably 15 μm or more. The metal strip may also be in the form of strips.

[0097] The weight of each metal strip is preferably 0.001 g or more and 0.050 g or less, more preferably 0.003 g or more and 0.040 g or less, and even more preferably 0.005 g or more and 0.020 g or less. Specifically, if the aluminum metal strip is 5 mm wide x 20 mm long and 30 μm thick, it will be about 0.008 g. 2.6 When the thermal conductive layer P2 includes an assembly of metal strips, the mass ratio W (metal) of the metal strip assembly in the thermal conductive layer P2 is preferably 30% or more. The mass ratio W (metal) of the metal strip assembly is more preferably 50% or more, and even more preferably 70% or more. The mass ratio W (metal) of the metal strip assembly is the ratio of the mass of the metal strip to the total mass of the thermal conductive layer P2, which includes not only the metal strip and the second thermoplastic resin, but also other additives, etc.

[0098] The method for measuring the mass percentage W (metal) is as follows: When the second thermoplastic resin contained in the thermal conductive layer P2 is polypropylene resin, first, the mass of the thermal conductive layer P2 is measured. Next, the resin of the thermal conductive layer P2 is burned off in a furnace at 500°C for 1 hour, and the mass of the sample before and after treatment is weighed to calculate the mass of the metal strip assembly. Then, the mass of the metal strip assembly is divided by the mass of the thermal conductive layer P2 to calculate the mass percentage W (metal) = 100 × mass of the metal strip assembly / mass of the thermal conductive layer P2

[0099] 3. Adhesion using the formed thermal conductive layer P2 The thermal conductive layer P2 of the present invention may be formed by bonding the formed thermal conductive layer P2 to the resin layer P1 with an adhesive. There are no particular limitations on the type of adhesive, and epoxy resin adhesives, cyanoacrylate adhesives, etc., can be used. Furthermore, it is preferable that the main components of the adhesive are polyolefin resin and water, and that it also contains DMAE (dimethylaminoethanol), TEA (triethylamine), and IPA (isopropyl alcohol).

[0100] [Thermal Conducting Layer P2: Shielding of Electric or Magnetic Fields] The thermal conducting layer P2 preferably shields at least one of an electric field or a magnetic field. It is preferable that the shielding of at least one of an electric field or a magnetic field is 10 decibels or more in at least a part of the region between 0 MHz and 3000 MHz. It is more preferable that the shielding of the electric field or magnetic field is 20 decibels or more, and even more preferable that it is 30 decibels or more. Here, the shielding can be expressed as 10 times (decibels) the common logarithm of the ratio of the power of the electromagnetic wave before passing through the thermal conducting layer P2 to the power of the electromagnetic wave after passing through the thermal conducting layer P2.

[0101] The preferred range for each shielding region is that in at least 50% of the region between 0 MHz and 3000 MHz, the shielding of the electric or magnetic field is preferably 10 decibels or more. More preferably, the shielding of the electric or magnetic field is 20 decibels or more, and even more preferably 30 decibels or more. "In at least 50% of the region between 0 MHz and 3000 MHz" means that the shielding region may be continuous or discontinuous within the region between 0 MHz and 3000 MHz.

[0102] Regarding the preferred range for each shielding region, it is preferable that the shielding of the electric or magnetic field is 10 decibels or more in all regions from 0 MHz to 3000 MHz. It is more preferable that the shielding of the electric or magnetic field is 20 decibels or more, and even more preferable that it is 30 decibels or more. The more preferable shielding characteristics will be described below.

[0103] The thermal conductive layer P2 shields at least one of the electric field or magnetic field, and it is preferable that the shielding of the electric field or magnetic field is 10 decibels or more in at least a portion of the region between 0 MHz and 100 MHz. It is more preferable that the shielding of the electric field or magnetic field is 20 decibels or more, and even more preferable that it is 30 decibels or more.

[0104] The preferred range for each shielding region is that in at least 50% of the region between 0 MHz and 100 MHz, the shielding of the electric or magnetic field is preferably 10 decibels or more. More preferably, the shielding of the electric or magnetic field is 20 decibels or more, and even more preferably 30 decibels or more. "In at least 50% of the region between 0 and 100 MHz" means that the shielding region between 0 MHz and 100 MHz may be continuous or discontinuous.

[0105] The preferred range for each shielding region is that the shielding of the electric or magnetic field is 10 decibels or more in all regions from 0 MHz to 100 MHz. It is more preferable that the shielding of the electric or magnetic field is 20 decibels or more, and even more preferable that it is 30 decibels or more.

[0106] [Horizontal Member for Automobiles] 1. Overview The horizontal member for automobiles of the present invention is a horizontal member that is mounted horizontally when it becomes an automobile part, and is made by laminating a resin layer P1 and a heat conductive layer P2. Layers other than the resin layer P1 and the heat conductive layer P2, such as an adhesive layer, may also be laminated.

[0107] A horizontal component does not necessarily have to be entirely horizontal; it is sufficient if part or most of it is horizontal. Examples include battery covers, battery bottom protective covers, roofs, hoods, and rear door hoods. To improve the flame resistance of automotive horizontal components, it is necessary to prevent them from sagging during combustion.

[0108] 2. Battery tray, battery cover, battery bottom protective cover The automotive horizontal member in the present invention is preferably a component of the battery box. The component of the battery box is preferably one of the battery tray, battery cover, or battery bottom protective cover.

[0109] 2.1 Battery Tray and Battery Cover Figure 2 is a cross-sectional view showing an example of a battery box. As shown in Figure 2, the battery 206 is housed in a battery box comprising a battery tray 208 and a battery cover 207. It is preferable that the components of the battery box are for vehicle use.

[0110] 2.2 Battery Bottom Protection Cover 2.2.1 The horizontal member for automobiles in the present invention may be a battery bottom protection cover. An example of a battery bottom protection cover is shown in Figure 2. More specifically, the battery bottom protection cover 201 is preferably fastened to the battery tray 208 at least in one place by a fastening rod 202, and the battery tray 208 preferably has an insertion hole 203 for fastening integrally molded.

[0111] 2.2.2 The battery tray 208 with insertion holes preferably includes an insertion base 204 that protrudes toward the battery bottom protective cover 201, and the insertion holes 203 are preferably located inside the insertion base 204.

[0112] 2.2.3 Impact-absorbing material It is preferable to place an impact-absorbing material 205 between the battery tray 208 and the battery bottom protective cover 201. Furthermore, it is more preferable that the impact-absorbing material 205 has a honeycomb structure. By providing such an impact-absorbing material 205, the impact resistance from the underside of the vehicle is improved.

[0113] 3. Thickness of the horizontal member for automobiles The thickness of the horizontal member for automobiles, which is formed by laminating a resin layer P1 and a heat conductive layer P2, is preferably 1.5 mm or more, more preferably 3 mm or more, and even more preferably 5 mm or more.

[0114] [Tensile Test Before and After Fire Resistance] The resin layer P1 preferably satisfies the following (a): (a) The tensile strength retention rate, as shown by formula (a1), is greater than 0.03%. A preferred tensile strength retention rate is 0.05% or more, more preferably 0.06% or more, and even more preferably 0.1% or more. Furthermore, the range of the tensile strength retention rate is preferably 0.04% to 50%, more preferably 0.05% to 40%, even more preferably 0.06% to 30%, and even more preferably 1% to 25%. If the tensile strength retention rate is greater than 0.03%, it is possible to maintain the shape of the resin layer P1 after combustion without resin dripping. Tensile strength retention rate (%) = (Tensile strength B after combustion ÷ Tensile strength A before combustion) × 100 ... formula (a1)

[0115] 1. When the horizontal member for automobiles is a battery cover: When the horizontal member for automobiles of the present invention is a battery cover, fire resistance against flames from the battery located inside the battery box is required. Furthermore, in the event of an accident, if leaked gasoline burns, the battery cover may be exposed to flames of 700 to 800°C. Therefore, fire resistance under more stringent conditions than conventional battery covers is required. Thus, fire resistance is important for the interior of the battery box. In this case, if the tensile strength retention rate of the resin layer P1 is greater than 0.03%, the battery cover will not come into contact with the battery itself after combustion due to resin dripping. In the case of a battery cover, it is preferable that the tensile strength retention rate of the resin layer P1 is 0.05% or more, and even more preferable that it is 0.07% or more.

[0116] Furthermore, after combustion, the battery cover is preferably subjected to a stress of 100 N or more when pressed from the non-flame side (upper side) with a push-pull gauge, more preferably 150 N or more, and even more preferably 200 N or more.

[0117] 2. When the horizontal member for automobiles is a battery tray: When the horizontal member for automobiles of the present invention is a battery tray, fire resistance is required for the battery box against flames from outside the vehicle, so fire resistance performance toward the outside of the battery box becomes important. When the horizontal member for automobiles is a battery tray, it is preferable that the tensile strength retention rate of the resin layer P1 is 0.04% or more, more preferably 0.06% or more, and even more preferably 0.1% or more.

[0118] [Sampling of Test Specimens: Residual Tensile Strength] The method for measuring the tensile strength retention rate will be described later, but the heat conductive layer P2 is peeled off from the horizontal member of an automobile to remove the resin layer P1, and 10 test specimens measuring 25 mm in width and 150 mm in length are cut from the resin layer P1. The tensile strength of 5 of the cut test specimens is measured, and the measurement result is defined as the tensile strength A before the combustion test. The remaining 5 test specimens are subjected to a combustion test, and the tensile strength of the 5 test specimens after the combustion test is measured, and the measurement result is defined as the tensile strength B after the combustion test.

[0119] [Workload] The resin layer P1 of the automotive horizontal member of the present invention preferably satisfies the following (b): (b) The amount of work per unit area in the tensile test of a 25 mm wide test piece after a combustion test is 0.1 × 10 －３ [(N・mm) / (g / m ２ ) ] 300 x 10 －３ [(N・mm) / (g / m ２ The following applies: Here, work is the value obtained by integrating the tensile force in the tensile test with respect to the amount of strain. Work per unit weight in the tensile test is the value obtained by integrating the load per unit weight in the tensile test with respect to the strain displacement.

[0120] For example, in the load-strain [%] curve for a tensile test shown in Figure 3, the work done in the tensile test can be calculated by integrating the load per unit area with respect to the strain amount [mm] in the load-strain [%] curve obtained by converting the displacement ratio of the strain on the horizontal axis [unit: %] to the displacement amount (unit: mm).

[0121] If the work done is above the lower limit, the resin layer P1 of the automotive horizontal member will not sag or drape down during combustion. Conversely, if it is below the upper limit, large pressure will not be required during press molding, making it easy to mold the automotive horizontal member. The preferred work done per unit area in the tensile test of a 25 mm wide test piece after combustion testing is 0.5 × 10⁻⁶. －３ [(N・mm) / (g / m ２ ) ] 100 x 10 －３ [(N・mm) / (g / m ２ )] less than 0.5 × 10 －３ [(N・mm) / (g / m ２ ) ] 50 x 10 －３ [(N・mm) / (g / m ２ )] less than 1.0 × 10 －３ [(N・mm) / (g / m ２ ) ] 30 x 10 －３ [(N・mm) / (g / m ２ )] less than 1.5 × 10 －３ [(N・mm) / (g / m ２ ) ] 20 x 10 －３ [(N・mm) / (g / m ２ )] less than 1.5 × 10 －３ [(N・mm) / (g / m ２ ) ] 10 x 10 －３ [(N・mm) / (g / m ２ It is less than ).

[0122] [Change in Load] The resin layer P1 of the present invention preferably satisfies the following (c0): (c0) In a tensile test on a test piece with a width of 25 mm after a combustion test, the load [N / (g / m)] at a strain of 0.1% to 0.2% ２ The change in ) ] is 0.005 × 10 －３ [N / (g / m) ２ ) ] 30 x 10 －３ [N / (g / m) ２ It is preferable that the following conditions are met.

[0123] A more favorable change is 0.01 × 10⁻⁶. －３ [N / (g / m) ２) ] 10 x 10 －３ [N / (g / m) ２ )] is within the following range, and a more preferable change is 0.05 × 10 －３ [N / (g / m) ２ )] 0.9 x 10 －３ [N / (g / m) ２ )] The range is as follows, and a more preferable change is 0.15 × 10 －３ [N / (g / m) ２ )] 0.8 x 10 －３ [N / (g / m) ２ The range is as follows, and the most preferred change is 0.15 × 10 －３ [N / (g / m) ２ )] 0.7 x 10 －３ [N / (g / m) ２ ) ] The following:

[0124] Load [N / (g / m)] at strains of 0.1% to 0.2% ２ The change in ) ] is 0.005 × 10 －３ [N / (g / m) ２ A load of [N / (g / m²)] or more means that a certain amount of stress is required to deform the fiber. In other words, the load at a strain of 0.1% to 0.2% is [N / (g / m²)]. ２ The change in ) ] is 0.005 × 10 －３ [N / (g / m) ２ )] or higher is preferable because the fibers will not sag when the horizontal member for automobiles burns. Load at strain of 0.1% to 0.2% [N / (g / m ２ The change in ) ] is 30 × 10 －３ [N / (g / m) ２ If the result is below this value, it means that the material could be easily molded without requiring a large load in the initial stage of applying the load.

[0125] [Average rate of change of load] 1. The resin layer P1 of the present invention preferably satisfies the following (c): (c) In a tensile test on a test piece with a width of 25 mm after a combustion test, the load [N / (g / m) at a strain of 0.1% to 0.2% ２ The average value of the change in ) ] (average rate of change) is 0.05 × 10 －３ [N / (g / m) ２ ) ] 300 x 10－３ [N / (g / m ２ )] is preferably below.

[0126] A more preferable average rate of change is 0.1×10 －３ [N / (g / m ２ )] or more and 100×10 －３ [N / (g / m ２ )] or less, and a still more preferable average rate of change is 0.5×10 －３ [N / (g / m ２ )] or more and 9.0×10 －３ [N / (g / m ２ )] or less, and an even more preferable average rate of change is 1.5×10 －３ [N / (g / m ２ )] or more and 8.0×10 －３ [N / (g / m ２ )] or less, and the most preferable average rate of change is 1.5×10 －３ [N / (g / m ２ )] or more and 7.0×10 －３ [N / (g / m ２ )] or less.

[0127] The average rate of change of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% being 0.05×10 －３ [N / (g / m ２ )] or more means that a certain amount of stress is required to deform the fiber. That is, if the average rate of change of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% is 0.05×10 －３ [N / (g / m ２ )] or more, when the horizontal member for an automobile burns, it is preferable because the fiber does not sag. If the average rate of change of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% is 300×10 －３ [N / (g / m ２ )] or less, it means that in the initial stage when a load is applied, a large load is not required and it is a material that can be easily formed. Here, the average rate of change of the load [N / (g / m ２ )] at a strain of 0.1% to 0.2% means, for example, the load [N / (g / m２ This is the slope of the arrow indicated by symbol 301 in the strain [%] curve.

[0128] 2. The resin layer P1 of the horizontal member for automobiles of the present invention preferably satisfies the following (d0): (d0) In a tensile test of a test piece with a width of 25 mm after a combustion test, the load [N / (g / m)] at a strain of 0.5% to 3.0% ２ The change in ) is -7.5 × 10 －３ [N / (g / m) ２ ) ] Above - 0.0125 × 10 －３ [N / (g / m) ２ )] is within the following range. More preferably, -2.5 × 10 －３ [N / (g / m) ２ )] Above - 0.025 × 10 －３ [N / (g / m) ２ The range is as follows: Load [N / (g / m)] ２ ) ] If the amount of change is a negative value, and within this range, it means that no large load other than the initial load during molding is required, and the material can be easily molded. 2. The resin layer P1 of the automotive horizontal member of the present invention preferably satisfies the following (d). (d) In a tensile test on a test piece with a width of 25 mm after a combustion test, the load [N / (g / m) at strains from 0.5% to 3.0% ２ The average value of the change in ) ] (average rate of change) is -3.0 × 10 －３ [N / (g / m) ２ )] Above - 0.005 × 10 －３ [N / (g / m) ２ )] is within the following range. More preferably, -1.0 × 10 －３ [N / (g / m) ２ )] Above - 0.01 x 10 －３ [N / (g / m) ２ )] is within the following range. Here, the load at strains from 0.5% to 3.0% is [N / (g / m ２ The average rate of change of the load [N / (g / m)] in Figure 3 is, for example, the load [N / (g / m)]. ２ )] - Strain [%] curve, this is the slope of the arrow indicated by symbol 302. Load [N / (g / m ２If the average rate of change of ) is a negative value, it means that within this range, no large load other than the initial load during molding is required, and the material can be easily molded.

[0129] [Range of strain at which the load per unit area is maximum] The resin layer P1 of the automotive horizontal member of the present invention preferably satisfies the following (e): (e) In a tensile test on a test piece with a width of 25 mm after a combustion test, the maximum load value is in the range of strain greater than 0% and less than 5%. It is more preferable that the maximum load value is in the range of strain greater than 0% and less than 2%, even more preferable that the maximum load value is in the range of strain greater than 0% and less than 1%, and even more preferable that the maximum load value is in the range of strain greater than 0% and less than 0.5%.

[0130] Having a maximum load value in the range of 0% to less than 5% strain means that the load obtained in a tensile test on a 25 mm wide test specimen after a combustion test is [N / (g / m)]. ２ )] - Strain [%] curve means that the peak of the maximum load is in the range of strain greater than 0% and less than 5%. Load [N / (g / m) ２ The strain[%] curve preferably has a peak of maximum load in the strain range of over 0% and less than 1%, and more preferably has a peak of maximum load in the strain range of over 0% and less than 0.5%.

[0131] When press-molding the molding material that will become the resin layer P1 using upper and lower molding dies, it is possible to apply stress to the molding material immediately after closing the upper and lower molding dies and sandwiching the molding material between them. By designing the material to have a maximum load value within the above range (the initial stage in which strain is large), it is possible to mold the same molding material (resin layer P1) more easily, even if it has the same amount of work done.

[0132] [Maximum load per unit area] The resin layer P1 of the automotive horizontal member of the present invention preferably satisfies the following (f): (f) In a tensile test of a test piece with a width of 25 mm after a combustion test, the maximum load per unit area is 1.1 × 10 －３ [N / (g / m) ２ ) ] or more. The maximum load per unit area is 1.15 × 10 －３ [N / (g / m) ２It is more preferable that it be 1.5 × 10 －３ [N / (g / m) ２ It is even more preferable that it be 2.0 × 10 －３ [N / (g / m) ２ It is even more preferable that it be 3.0 × 10 －３ [N / (g / m) ２ It is most preferable that the maximum load per unit area be 1.1 × 10 －３ [N / (g / m) ２ ) ] ] is preferable because when the horizontal member for automobiles burns, the fibers do not sag. Also, the maximum load per unit area for the same amount of work is 1.1 × 10 －３ [N / (g / m) ２ By doing so, if a large load is applied at a specific molding stage, molding can be easily performed with a small load at other stages, eliminating the need to continuously apply a large load throughout the entire molding process.

[0133] On the other hand, the maximum load per unit area is 10 x 10 －３ [N / (g / m) ２ It is more preferable that the maximum load per unit area for the same amount of work is 10 × 10 －３ [N / (g / m) ２ If the following conditions are met, a large load is not required when forming the horizontal members for automobiles, and they can be easily formed.

[0134] [Air volume blown onto the reinforcing fibers after cutting] There are no particular limitations on the method for manufacturing a molding material that produces a resin layer P1 in which the thermal conductivity tc1 satisfies equation (2) and the above-mentioned [work done], [average rate of change of load], [range of strain where the load per unit weight is the maximum value], and [maximum load per unit weight] satisfy values ​​(b) to (f). However, after cutting the reinforcing fibers, compressed air can be supplied using a compressor directly below the cutting device, and the amount of this compressed air can be adjusted to the desired range of [work done], [average rate of change of load-strain curve], and [maximum load per unit weight].

[0135] [Preparation of Molding Material] [Materials] 1. Reinforcing Fiber Two types of reinforcing fibers were prepared: (1) Glass fiber multi-end roving (Owens Corning: OC Paneluxe® 2400Tex) (2) Glass fiber single-end roving (Owens Corning: SE2348 roving 2000Tex) 2. Resin Polypropylene resin: Novatec® PP BC03C manufactured by Nippon Polypropylene Co., Ltd. 3. Flame retardant ADEKA® FP2100-JC manufactured by ADEKA Corporation

[0136] [Example 1] 1. Preparation of molding material to become resin layer P1 As a thermoplastic resin, a mixture of polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.) and 11 parts by mass of flame retardant (Adekastab FP2100-JC) was prepared. A unidirectional, continuously moving, permeable support with a suction mechanism at its bottom was installed below the polypropylene resin dispenser. While moving the permeable support at 2 m / min, the polypropylene resin was sprayed from the dispenser onto the permeable support, and the polypropylene resin was fixed onto the permeable support to prepare a polypropylene resin assembly.

[0137] A rotary cutter was placed above the breathable support, and the glass fiber single-ended roving (2) was cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air was supplied directly below the rotary cutter, and the negative pressure generated in the airflow separated the glass fibers from the roll. The compressed air flow rate was 170 L / min.

[0138] Cut glass fibers were scattered onto a pre-fabricated polypropylene resin aggregate on a breathable support and fixed to create a composite composition consisting of glass fiber aggregates and polypropylene resin aggregates, with a width of 600 mm and a length of 3 m. The production speed of the composite composition was 2 m / min. The prepared composite composition consisting of glass fiber aggregates and polypropylene resin aggregates was heated in a continuous impregnation device to impregnate the glass fibers with polypropylene resin, and then cooled to obtain molding material 1. When cutting the glass fibers to a constant length of 20 mm using a rotary cutter, the supply amount of glass fibers was set so that the volume ratio of glass fibers was 40% of molding material 1, and the average thickness of molding material 1 was 3.0 mm.

[0139] 2. Preparation of heat conductive layer P2 A commercially available aluminum plate (UACJ A1050-O) was prepared with a thickness of 0.2 mm and dimensions of 300 mm x 300 mm. 3. Creation of automotive horizontal member (lamination) An anchor coating agent was applied to the above aluminum plate with adhesive (YA-6010), a 3.0 mm thick molding material 1 was prepared with dimensions of 300 mm x 300 mm and laminated, and the molding material 1 and the aluminum plate were pressed together to form an automotive horizontal member.

[0140] [Example 2] The heat conductive layer P2 has 25 holes with a diameter of 1 mm per 100 mm. ２ A horizontal member for an automobile was manufactured in the same manner as in Example 1, except that it was evenly distributed.

[0141] [Comparative Example 1] A molded component for automobiles was made using only the molding material 1 with a thickness of 3 mm, without providing the heat conductive layer P2.

[0142] [Thermal Conductivity] The thermal conductivity tc1 of the resin layer P1, the thermal conductivity tc2 of the thermal conductivity layer P2, and the thermal conductivity tc3 of the automotive horizontal member were measured as follows: (Disk Heat Flow Meter Method) The thermal conductivity was measured using the disk heat flow meter method in accordance with ASTM E1530. A Unithermo 2021 (manufactured by Antar Co., Ltd.) was used for the measurement. The measurement temperature was set to 120°C. A disk with a diameter of 50 mm was cut from a molded material 1 with a thickness of 3.0 mm to serve as the resin layer test piece. The measured thermal conductivity was defined as the thermal conductivity tc1 of the resin layer P1. The thermal conductivity tc1 was 0.331 [W / (m·K)]. A disk with a diameter of 50 mm was cut from a commercially available 300 mm × 300 mm aluminum plate (UACJ A1050-O) with a thickness of 0.2 mm to serve as the thermal conductivity layer test piece. The measured thermal conductivity was defined as the thermal conductivity tc2 of the thermal conductivity layer P2. The thermal conductivity tc2 was 237 [W / (m·K)]. With the resin layer test piece and the thermal conductivity layer test piece superimposed, the thermal conductivity was measured using a disc heat flow meter method with a Unithermo 2021 (manufactured by Antar Co., Ltd.). The measured thermal conductivity was defined as the thermal conductivity tc3 of the automotive horizontal member. The thermal conductivity tc3 was 0.338 [W / (m·K)].

[0143] [Evaluation Method] Combustion Test (1) Observation of Solidified Layer P3 and Expanded Layer P4 A test plate (300 mm x 300 mm) of the horizontal member for automobiles prepared in Examples 1 and 2 and Comparative Example 1 was prepared. This test plate was placed on a 300 mm square horizontal jig, and a combustion burner was set up so that the distance between the surface of the resin layer P1 and the nozzle of the combustion burner was 60 mm. The flame temperature was adjusted to be between 950°C and 1000°C, and while maintaining that temperature range, the surface of the resin layer P1 was burned for 10 minutes, and the surface temperature of the heat conduction layer P2 at a position 70 mm horizontally away from the center of the area where the flame of the combustion burner was applied (combustion center) was measured using a non-contact thermometer (A&D AD-5611A). After 600 seconds, extinguishing water was sprayed, and the sample was removed after the temperature of the horizontal member for automobiles had cooled down completely. For each sample taken, the overall thickness was measured, and the sum of the thicknesses of the solidified layer and the expanded layer was calculated by subtracting the thickness of the thermal conductive layer P2 from the overall thickness. Additionally, a 0.45 mm thick all-purpose M-type cutter knife (model number: 203B, manufactured by Olfa Corporation) was inserted from the side opposite to the thermal conductive layer P2, and the depth to which it could be inserted without resistance was defined as the thickness of the expanded layer. The difference between the sum of the thicknesses of the solidified layer and the expanded layer, minus the thickness of the expanded layer, was then defined as the thickness of the solidified layer.

[0144] (2) Surface Temperature Measurement A thermocouple was attached with adhesive to the surface of the heat conduction layer P2 on the non-flame side, at a position 70 mm away from the center of combustion, on a test plate (300 mm x 300 mm) of the automotive horizontal member prepared in Examples 1 and 2 and Comparative Example 1. This test plate was placed on a 300 mm square horizontal jig, and the combustion burner was set up so that the distance between the surface of the resin layer P1 and the nozzle of the combustion burner was 60 mm. The flame temperature was adjusted to be between 950°C and 1000°C, and while maintaining this temperature range, the surface of the resin layer P1 was burned for 1800 seconds, and the surface temperature of the heat conduction layer P2 at a position 70 mm horizontally away from the center of combustion was measured with a thermocouple. After 1800 seconds, extinguishing water was sprayed, and the sample was removed after the temperature of the automotive horizontal member had cooled completely.

[0145] Table 1 shows the evaluation results for the examples and comparative examples.

[0146]

[0147] [Reference Examples] The following reference examples and reference comparative examples are described for the purpose of evaluating only the resin layer P1.

[0148] [Reference Example 1] A polypropylene resin composition was prepared by adding 11 parts by mass of a flame retardant (Adekastab FP2100-JC) to polypropylene resin (PP) (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.). A unidirectional, continuously moving, permeable support having a suction mechanism at its bottom was installed below the polypropylene resin composition dispenser. While moving the permeable support at 2 m / min, the polypropylene resin composition was sprayed from the dispenser onto the permeable support, and the polypropylene resin composition was fixed onto the permeable support to prepare a polypropylene resin assembly.

[0149] A rotary cutter was placed above the breathable support, and the glass fiber multi-end roving (1) was cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air was supplied directly below the rotary cutter, and the negative pressure generated in the airflow separated the glass fibers from the roll. The compressed air flow rate was 170 L / min.

[0150] Cut glass fibers were scattered onto a pre-fabricated polypropylene resin aggregate on a breathable support and fixed to create a composite composition consisting of glass fiber aggregates and polypropylene resin aggregates, with a width of 600 mm and a length of 3 m. The manufacturing speed of the composite composition was 2 m / min. The composite composition consisting of the prepared glass fiber aggregates and polypropylene resin aggregates was heated in a continuous impregnation device to impregnate the glass fibers with the polypropylene resin aggregates, and then cooled to obtain reference molding material 1. When cutting the glass fibers to a constant length of 20 mm using a rotary cutter, the supply amount of glass fibers was set so that the volume ratio of glass fibers to reference molding material 1 was 40%, the volume ratio of polypropylene resin aggregates was 60%, and the average thickness of reference molding material 1 was 2.0 mm. The prepared reference molding material 1 was cold-pressed to form a resin layer P1.

[0151] [Reference Example 2] The resin layer P1 is prepared in the same manner as in Reference Example 1, except that the airflow rate when supplying compressed air is 50 L / min. [Reference Example 3] The resin layer P1 is prepared in the same manner as in Reference Example 1, except that the airflow rate when supplying compressed air is 230 L / min. [Reference Example 4] The resin layer P1 is prepared in the same manner as in Reference Example 1, except that the airflow rate when supplying compressed air is 300 L / min. [Reference Example 5] As the thermoplastic resin, a mixture of polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.) with 11 parts by mass of flame retardant (Adeka Stab FP2100-JC) added was prepared. Figure 5 shows a graph representing the load-strain curve in the tensile test of Reference Example 5.

[0152] A unidirectional, continuously moving, breathable support with a suction mechanism at its bottom was installed below the polypropylene resin supply machine. While moving the breathable support at 2 m / min, the polypropylene resin was sprayed from the supply machine onto the breathable support, fixing the polypropylene resin onto the breathable support to prepare a polypropylene resin assembly. The glass fiber multi-end roving (1) was slit to a target fiber width of 1 mm using a slitting device (cutting by pressing against a rubber roll) to separate the fibers. The slit glass fiber multi-end roving (1) and the glass fiber single-end roving (2) were supplied to a rotary cutter installed above the breathable support so that they were in a 1:1 volume ratio, and cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air was supplied directly below the rotary cutter, and the negative pressure generated by the airflow separated the glass fibers from the roll. The compressed air flow rate was 170 L / min. Cut glass fibers were scattered onto a pre-fabricated polypropylene resin aggregate on a breathable support and fixed to create a composite composition consisting of glass fiber aggregates and polypropylene resin aggregates, with a width of 600 mm and a length of 3 m. The manufacturing speed of the composite composition was 2 m / min. The prepared composite composition consisting of glass fiber aggregates and polypropylene resin aggregates was heated in a continuous impregnation device to impregnate the glass fibers with polypropylene resin, and then cooled to obtain a reference molding material 5. When cutting the glass fibers to a constant length of 20 mm using a rotary cutter, the supply amount of glass fibers was set so that the volume ratio of glass fibers to reference molding material 5 was 38%, the volume ratio of polypropylene resin aggregates was 62%, and the average thickness of reference molding material 5 was 2.0 mm. The prepared reference molding material 5 was cold-pressed to form a resin layer P1.

[0153] [Reference Example 1] This is prepared in the same manner as Reference Example 1, except that the airflow rate when supplying compressed air is set to 0 L / min.

[0154] Table 2 shows the materials, volume percentage or parts by mass, and compressed air volume for Reference Examples 1 to 5 and Reference Comparative Example 1.

[0155] [Evaluation of Reference Examples and Reference Comparative Examples] 1. Tensile Strength Retention Rate 1.1 Ten test pieces were cut from the resin layer P1 prepared in Reference Examples 1 to 5 and Reference Comparative Example 1, with a width of 25 mm and a length of 150 mm. 1.2 Tensile tests were performed on five of the obtained test pieces in accordance with ASTM D3039 (2019) at a loading speed of 1 mm / min., and the tensile strength was measured. The average value of the five pieces was taken as the tensile strength A before the combustion test. 1.3 Combustion Test A combustion test was performed on the remaining five test pieces. As shown in Figure 1, both ends of the test piece 101 were sandwiched between aluminum plates 105 with a 40 mm gap in the length direction, and the resin in the 40 mm lengthwise region (combustion region 102) in the center of the test piece 101 was directly burned with a flame 103 of a 1000°C gas burner. The burner nozzle 104 was kept 60 mm away from the test piece 101 during combustion. Depending on the test specimen, the temperature and time required to completely burn the resin in the combustion region 102 may vary. Therefore, the back surface temperature is measured using a non-contact thermometer (A&D AD-5611A, Inc.) at a distance of 30 cm from the back surface on the opposite side (upper side of Figure 1) from the gas burner flame 103 in the center of the test specimen 101. After confirming that the back surface temperature is 350 degrees Celsius or higher, the test specimen 101 is burned for 5 minutes. If the flame that ignited the test specimen 101 does not go out even after the gas burner flame 103 is extinguished after 5 minutes of burning, wait until it is completely extinguished and do not actively extinguish the flame. Depending on the type of resin, the resin in the combustion region 102 may not be completely burned off even under the above conditions. In this case, additional heating is recommended. 1.4 Tensile tests are performed on five test specimens after the combustion test in accordance with ASTM D3039 (2019) at a load rate of 1 mm / min. to measure the tensile strength. The average value of the five points is defined as the tensile strength B after the combustion test. 1.5 The tensile strength retention rate is calculated using formula (a1) from the tensile strength A before the combustion test and the tensile strength B after the combustion test.

[0156] 2. Work done and average rate of change after initial load application 2.1 Six test pieces, 25 mm wide and 150 mm long, are cut from an automotive horizontal member. 2.2 The test pieces are burned under the same conditions as in "1.3 Combustion Test" in "1. Tensile Strength Retention Rate" above. 2.3 Following Method A (strip method) of 8.14.1a) of JIS L 1096:2010, each of the six burnt test pieces is stretched at a tensile speed of 1 mm / min using a constant-speed elongation tensile testing machine with a grip spacing of 100 mm. The work done for each test piece is calculated by integrating the load in the tensile test with respect to the strain amount [mm], and the average value for the six test pieces is determined. Furthermore, by dividing the difference between the load at 0.2% strain and the load at 0.1% strain by the change in strain of 0.1%, the average value (average rate of change) of the load change per unit of strain change from 0.1% to 0.2% strain was calculated, and the average value for the six test specimens was determined. In addition, by dividing the difference between the load at 3.0% strain and the load at 0.5% strain by 2.5%, the average value (average rate of change) of the load change per unit of strain change from 0.5% to 3.0% strain was calculated, and the average value for the six test specimens was determined. Note that in Reference Comparative Example 1, the strain at which the load was maximum was less than 0.1%, and the loads at strains of 0.1%, 0.2%, 0.5%, and 3% were below the measurement limit.

[0157] 3. Springback Rate Two of the reference molding materials prepared in each of the reference examples are cut to 100 mm x 100 mm and stacked together. A thermocouple is inserted in the center of the joining surface, and the mixture is placed in a preheating furnace heated to 280°C (upper and lower heater temperature). Heating is continued until the thermocouple temperature reaches 275°C. When the thermocouple temperature reaches 210°C, the mixture is removed from the furnace, cooled and solidified, and the thickness after preheating is measured. The ratio of the thickness before preheating to the thickness after preheating, expressed by the following formula, is calculated as the springback rate: Springback rate = Thickness after preheating (mm) / Thickness before preheating (mm)

[0158] 4. For moldability, the reference molding material (flat plate) prepared in each of the reference examples is cut to a length of 205 mm x width of 95 mm, two plates are stacked to a thickness of 2 mm, and dried in a hot air dryer at 120°C for 4 hours, then heated to 240°C using an infrared heater. Next, a flat plate-shaped mold is prepared and set to 60°C, and the two stacked reference molding materials are placed on top of it so as to overlap the opening, and the mold is closed by clamping it using a mechanical servo press (ZENFormer® MPS4200, manufactured by Hodenshimitsu Kako Kenkyusho Co., Ltd.). The thickness of the obtained press-molded body is observed and the moldability is evaluated by comparing the thickness with that of the reference molding material prepared in the reference example to see how much it has decreased. Perfect: Thickness reduction rate of 30% or more Excellent: Thickness reduction rate of 20% or more and less than 30% Better: Thickness reduction rate of 10% or more and less than 20% Good: Thickness reduction rate of 5% or more and less than 10% Bad: Thickness reduction rate of less than 5%

[0159] 5. Prepare 10 test pieces of the resin layer P1 created in the reference example of thermal insulation, each 300 mm wide and 300 mm long. Place the test pieces on a frame-mounted test stand capable of accommodating a 300 mm square, and directly burn the center of each test piece with a 1000°C burner flame. Burn for 3 minutes with the burner nozzle 60 mm away from the test piece, and measure the temperature of the back surface opposite the burner flame at the center of the test piece using a non-contact thermometer (A&D AD-5611A, Inc.) at a distance of 30 cm from the test piece. Excellent: The back surface temperature during measurement is 200°C or less for 3 minutes from the start of flame contact. Very Good: The back surface temperature exceeds 200°C between 70 seconds and less than 3 minutes from the start of flame contact. Good: The back surface temperature exceeds 200°C between 10 seconds and 70 seconds from the start of flame contact. Unacceptable: The back surface temperature exceeds 200°C within 10 seconds of flame application. The evaluation results are shown in Table 3.

[0160]

Claims

1. A horizontal automotive member comprising a resin layer (P1) containing reinforcing fibers with a weight-average fiber length of 5 mm to 100 mm and resin, and a thermal conductive layer (P2) laminated on the resin layer (P1), wherein the thermal conductivity tc1 of the resin layer (P1) satisfies the following formula (2), and the thermal conductivity tc2 of the thermal conductive layer (P2) satisfies the following formula (3). Formula (2) 0.01 W / (m·K) < tc1 < 10 W / (m·K) Formula (3) 100 W / (m·K) < tc2 2. A horizontal automotive member according to claim 1, wherein the thickness t1 of the resin layer (P1) satisfies the following formula (4), the thickness t2 of the heat conductive layer (P2) satisfies the following formula (5), and when the horizontal automotive member is observed 600 seconds after the surface of the horizontal automotive member on the resin layer (P1) side is heated with a burner flame to 1000°C, the resin layer (P1) transitions into a solidified layer (P3) in which reinforcing fiber springback has not occurred and an expanded layer (P4) in which reinforcing fiber springback has occurred, the thickness t3 of the solidified layer (P3) satisfies the following formula (6), and the thickness t4 of the expanded layer (P4) satisfies the following formula (7). Equation (4) 1.3mm<t1<10.0mm Equation (5) 0.005mm<t2<1.0mm Equation (6) t1×0.1<t3<t1×0.7 Equation (7) t1×0.3×1.05<t4<t1×0.9×8 3. A horizontal automotive member according to either claim 1 or 2, wherein the thermal conductivity tc3 in the thickness direction of the horizontal automotive member satisfies the following formulas (8) and (9): Formula (8) 0.8 < tc3 / tc1 < 1.2 Formula (9) 0.1 W / (m·K) < tc3 < 10 W / (m·K) 4. The horizontal automotive member according to any one of claims 1 to 3, wherein the surface of the horizontal automotive member with the resin layer (P1) side is exposed to flame from a burner so that the flame surface reaches 1000°C, the temperature of the surface with the heat conduction layer (P2) side is measured at a position 70 mm away from the center of the flame contact position, and the curve plotted for the temperature has a region in which the slope becomes negative between 900 seconds after the start of flame contact and before 1800 seconds have elapsed.

5. The horizontal member for automobiles according to any one of claims 1 to 4, wherein the resin layer (P1) contains a flame retardant, and the flame retardant is in an amount of 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of thermoplastic resin, and satisfies the following (a) and (b): (a) The tensile strength retention rate shown by formula (a1) is greater than 0.03%. Formula (a1) Tensile strength retention rate (%) = (Tensile strength B after combustion ÷ Tensile strength A before combustion) × 100 (b) The amount of work per unit area in a tensile test on a test piece with a width of 25 mm after a combustion test is 0.1 × 10 －３ [(N・mm) / (g / m ２ ) ] 300 x 10 －３ [(N・mm) / (g / m ２ )] Below, and with a maximum load per unit area of ​​1.1 × 10 －３ [N / (g / m) ２ That's all.

6. The horizontal member for automobiles according to claim 5, wherein the resin layer (P1) has a maximum load per unit area in a tensile test of a 25 mm wide test piece after a combustion test, with the strain in the range of more than 0% and less than 5%.

7. The horizontal member for a vehicle according to any one of claims 5 or 6, wherein the resin layer (P1) satisfies the following (c). (c) In a tensile test on a test piece after a combustion test with a width of 25 mm, the average change rate of the load [N / (g / m ２ )] from a strain of 0.1% to 0.2% is in the range of 0.05×10 －３ [N / (g / m ２ )] or more and less than 300×10 －３ [N / (g / m ２ )].

8. The resin layer (P1) is a horizontal member for automobiles according to any one of claims 5 or 6, satisfying the following (c0): (c0) In a tensile test of a 25 mm wide test piece after a combustion test, the load [N / (g / m)] at a strain of 0.1% to 0.2% ２ The change in ) ] is 0.05 × 10 －３ [N / (g / m) ２ ) ] 300 x 10 －３ [N / (g / m) ２ It is in the range of less than ).

9. The resin layer (P1) is a horizontal member for automobiles according to any one of claims 5 to 8, satisfying (d) below: (d) In a tensile test of a test piece with a width of 25 mm after a combustion test, the load [N / (g / m)] at strains from 0.5% to 3% ２ The average rate of change of ) ] is -3.0 × 10 －３ [N / (g / m) ２ )] Above - 0.005 × 10 －３ [N / (g / m) ２ ) ] The range is as follows:

10. The resin layer (P1) satisfies the following (d0), the horizontal member for automobiles according to any one of claims 5 to 8: (d0) In a tensile test of a test piece with a width of 25 mm after a combustion test, the load [N / (g / m)] at strains of 0.5% to 3% ２ The change in ) is -7.5 × 10 －３ [N / (g / m) ２ ) ] Above - 0.0125 × 10 －３ [N / (g / m) ２ ) ] The range is as follows:

11. The horizontal member for an automobile according to any one of claims 1 to 10, wherein the thermoplastic resin is polypropylene resin and the reinforcing fiber is glass fiber.

12. The automotive horizontal member according to any one of claims 1 to 11, wherein the automotive horizontal member is a battery cover or a battery bottom protective cover.

13. The horizontal member for automobiles according to any one of claims 1 to 12, wherein the springback rate of the resin layer (P1) is 1.2 or more and 8.0 or less.

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