Automotive underfloor insulation mat and method of manufacturing the same

Abstract

The present application relates to a kind of automobile lower heat insulation pad and its manufacturing method, it includes: glass fiber cotton layer;First aluminum foil layer, it is located in one side of the glass fiber cotton layer;Composite felt layer is bonded to the side of the first aluminum foil layer away from the glass fiber cotton layer, the side of the composite felt layer away from the first aluminum foil layer is fluffy.Partially fused bonded composite felt layer and first aluminum foil layer form reflective layer structure, when engine noise, radiant heat passes through composite felt, noise and radiant heat are reflected in first aluminum foil layer, in the fiber with sound-absorbing effect that still maintains certain fluffy and the fiber with sound-insulating effect that is fused and bonded together in primary attenuation, and into glass fiber cotton is transmitted, vibrates, adheres, scatters and attenuates, glass fiber cotton has very good heat insulation characteristics, noise and heat are greatly attenuated in this structure, significantly improve the soundproof effect, while achieving better heat insulation effect.

Description

Technical Field

[0001] This invention relates to the field of sound and heat insulation technology for automotive body systems, and particularly to an underbody heat insulation pad for automobiles and its manufacturing method. Background Technology

[0002] With the development of the automotive industry and increasingly fierce market competition, commercial vehicles are paying more and more attention to comfort. The heat insulation pad under the floor of the commercial vehicle is fixed to the outside of the cab floor and covers the engine. It plays a role in blocking or reducing the transmission of radiant heat and noise from the engine to the cab, thereby improving the driving experience for customers.

[0003] In related technologies, the mainstream heat insulation pad structure for commercial vehicles is "aluminum foil or non-woven fabric + fiberglass wool + non-woven fabric or waste felt," with the aluminum foil layer facing the engine. While this ensures basic reflection of engine radiant heat and noise, aluminum foil is also a good conductor of heat and sound. Furthermore, the aluminum foil is thin, relying solely on the outer layer of aluminum foil and fluffy fiberglass wool, along with waste felt (which also provides insulation, offering some effect in thicker areas), while the insulation effect in other compacted areas remains relatively unsatisfactory. Importantly, the overall sound insulation and noise reduction of the lower heat insulation pad is quite poor. For example, the traditional lower heat insulation pad for a certain vehicle model has a main body thickness of 5mm to 14mm and a surface density of approximately 1400 to 1600 g / m³. 2 The component weighs approximately 3.45 kg. Under a standard thermal test environment of 80℃, its heat insulation was measured to be ΔT = 51℃. The sound insulation range using the standing wave tube method (100Hz~5000Hz, the same below) was 6.2~15.0 dB, with an average sound insulation of 10.3 dB. Therefore, to further improve the heat and sound insulation effects, it is necessary to increase the amount of fiberglass insulation and the thickness of the heat insulation pad. This results in a significant increase in the component's weight. For example, the heat insulation pad under a certain Volvo model, under a standard thermal test environment of 80℃, showed a noticeable improvement in heat insulation (ΔT = 55℃). The sound insulation range using the standing wave tube method was 9.2~18.8 dB, with an average sound insulation of 14.4 dB, indicating some improvement in sound insulation, but not significant. Furthermore, its surface density reached 3000~3800 g / m². 2 The main body thickness is 23mm to 35mm, and the parts weigh more than 8kg, resulting in low cost-effectiveness due to the increased weight. Summary of the Invention

[0004] This invention provides an automotive underbody heat insulation pad and its manufacturing method to solve the problems of unsatisfactory heat insulation and sound insulation effects, heavy weight, and low cost-effectiveness in related technologies.

[0005] Firstly, an automotive underbody heat insulation pad is provided, comprising: a fiberglass wool layer; a first aluminum foil layer disposed on one side of the fiberglass wool layer; and a composite felt layer bonded to the side of the first aluminum foil layer opposite to the fiberglass wool layer, wherein the side of the composite felt layer opposite to the first aluminum foil layer is fluffy. When engine noise and radiant heat pass through the composite felt, the noise and radiant heat are reflected by the first aluminum foil layer, undergo initial attenuation in the sound-absorbing fibers that still maintain a certain fluffy shape and the sound-insulating fibers that are fused together, and then enter the fiberglass wool for transmission, vibration, adhesion, and scattering, resulting in further attenuation. The fiberglass wool has excellent heat insulation properties, and noise and heat are significantly attenuated in this structure, significantly improving the sound insulation effect while achieving better heat insulation.

[0006] In some embodiments, a second aluminum foil layer is provided on the side of the glass fiber cotton layer opposite to the first aluminum foil layer.

[0007] In some embodiments, both the first aluminum foil layer and the second aluminum foil layer are non-porous aluminum foils with a film thickness of 20–60 mm and an areal density of 50–160 g / m³. 2 .

[0008] In some embodiments, a nonwoven fabric layer is provided on the side of the second aluminum foil layer opposite to the glass fiber cotton layer, and the areal density of the nonwoven fabric layer is 130±40 g / m³. 2 .

[0009] In some embodiments, the composite felt layer is formed by needle punching a blend of pre-oxidized filament fiber and thermoplastic organic fiber in a ratio of 80%:20% to 40%:60%.

[0010] In some embodiments, the composite felt layer includes at least one of pre-oxidized fiber composite felt, carbon fiber composite felt, and thermoplastic organic fiber composite felt.

[0011] In some embodiments, the content of the composite felt layer gradually increases from the side away from the first aluminum foil layer to the side closer to the first aluminum foil layer.

[0012] In some embodiments, the thickness of the glass fiber cotton layer is 5–25 mm, and the areal density is 350–1600 g / m³. 2 .

[0013] In some embodiments, the thickness of the composite felt layer is 3mm to 8mm, and the areal density is 200 to 520g / m³. 2 .

[0014] Secondly, a method for manufacturing an automotive underbody heat insulation pad is provided, comprising the following steps: laying a non-woven fabric layer → a second aluminum foil layer → a fiberglass wool layer → a first aluminum foil layer → a composite felt layer sequentially on a mold, such that the non-woven fabric layer, the second aluminum foil layer, the fiberglass wool layer, the first aluminum foil layer, and the composite felt layer are stacked sequentially; closing the mold and simultaneously heating the material from both top and bottom; applying pressure to thermally bond and shape each layer, forming the automotive underbody heat insulation pad, wherein the side of the composite felt layer opposite to the first aluminum foil layer is fluffy. By pre-laying the composite felt layer, the first aluminum foil layer, the fiberglass wool layer, the second aluminum foil layer, and the non-woven fabric layer in a mold and then heating and shaping them into an integrated structure, the resulting underbody heat insulation pad, at the same areal density, not only improves heat insulation performance but also provides better sound absorption and insulation.

[0015] The beneficial effects of the technical solution provided by this invention include:

[0016] This invention provides an automotive underbody heat insulation pad and its manufacturing method. Utilizing the high sound and heat reflectivity of the uneven surface of aluminum foil and the properties of glass fiber, a partially fused and bonded composite felt layer forms a reflective layer structure with the first aluminum foil layer. When engine noise and radiant heat pass through the composite felt, the noise and radiant heat are reflected in the first aluminum foil layer. Initial attenuation occurs in the sound-absorbing fibers (which still maintain a certain degree of fluffiness) and the sound-insulating fibers (which are fused together). The noise and heat are then attenuated through transmission, vibration, adhesion, and scattering within the glass fiber cotton. The glass fiber cotton has excellent heat insulation properties, and noise and heat are significantly attenuated in this structure, significantly improving sound insulation while achieving better heat insulation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the composite material layup structure of the automotive underbody heat insulation pad provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the automotive under-heat insulation pad provided in an embodiment of the present invention.

[0020] Numbering on the map:

[0021] 1. Fiberglass wool layer; 2. First aluminum foil layer; 3. Composite felt layer; 4. Second aluminum foil layer; 5. Non-woven fabric layer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] CN203957446U discloses a heat insulation pad for commercial vehicles, comprising fiberglass cloth with an aluminum foil layer (surface) and a waste textile felt layer (backing) on ​​its upper and lower surfaces, respectively. The waste textile felt replaces non-woven fabric, resulting in a compact structure after compression, thus improving upon the shortcomings of CN201900756U. It also enhances the strength of the lower heat insulation pad components to some extent, prevents fiberglass dust from falling off, and, being flame-retardant, improves sound absorption and heat insulation performance. This patented structure has been applied to heat insulation pads in Dongfeng commercial vehicles; for example, in one of the aforementioned models, its surface density is approximately 1400–1600 g / m³. 2 The heat insulation was measured to be ΔT = 51℃ under the standard test thermal environment of 80℃. The sound insulation range of the standing wave tube method (100Hz~5000Hz) was 6.2~15.0dB, with an average sound insulation of 10.3dB. It has a certain heat insulation and sound insulation effect. However, the customer has put forward higher requirements for the thermal and noise environment of the cab. In order to meet the requirements, we can only gradually increase the amount and thickness of the intermediate glass fiber cotton.

[0024] This invention provides an automotive underbody heat insulation pad and its manufacturing method, which can solve the problems of unsatisfactory heat insulation and sound insulation effects, heavy weight, and low cost performance in related technologies.

[0025] See Figure 1As shown in the illustration, an automotive underbody heat insulation pad provided in this embodiment of the invention may include: a glass fiber cotton layer 1; a first aluminum foil layer 2 disposed on one side of the glass fiber cotton layer 1; and a composite felt layer 3 bonded to the side of the first aluminum foil layer 2 opposite to the glass fiber cotton layer 1. The side of the composite felt layer 3 opposite to the first aluminum foil layer 2 is fluffy. In this embodiment, by utilizing the mirror-like properties of the uneven aluminum foil and its high reflectivity for sound and heat, as well as the properties of glass fiber, the partially fused and bonded composite felt layer forms a reflective layer structure with the first aluminum foil layer. When engine noise and radiant heat pass through the composite felt, the noise and radiant heat are reflected in the first aluminum foil layer. They undergo initial attenuation in the still fluffy, sound-absorbing fibers and the fused and bonded, sound-insulating fibers, and then enter the glass fiber cotton for transmission, vibration, adhesion, and scattering, resulting in further attenuation. The glass fiber cotton has excellent heat insulation properties, and noise and heat are significantly attenuated in this structure, significantly improving the sound insulation effect while achieving better heat insulation.

[0026] See Figure 1 As shown, in some embodiments, a second aluminum foil layer 4 is provided on the side of the glass fiber cotton layer 1 facing away from the first aluminum foil layer 2. In this embodiment, from the engine to the cab direction, a double aluminum foil reflective cavity structure is formed by adhering a layer of aluminum foil to each side of the glass fiber cotton and cooperating with the glass fiber cotton layer 1. The two structures improve the heat insulation and sound insulation performance of the composite material, greatly reduce the heat and noise transmission rate, and play a blocking role. When engine noise and radiant heat pass through the composite felt, the noise and radiant heat are reflected by the first aluminum foil layer, and undergo initial attenuation in the sound-absorbing fibers that still maintain a certain fluffy shape and the sound-insulating fibers that are fused together. The penetrating noise and heat enter the double aluminum foil reflective cavity structure, are reflected back and forth between the two layers of aluminum foil, and are continuously transmitted, vibrated, adhered, and scattered in the glass fiber cotton for attenuation. Moreover, the glass fiber cotton itself has good heat insulation properties, and the noise and heat are greatly attenuated in this structure, significantly improving the sound insulation effect and achieving a better heat insulation effect.

[0027] See Figure 1 As shown, in some embodiments, both the first aluminum foil layer 2 and the second aluminum foil layer 4 are non-porous aluminum foils with a film thickness of 20–60 mm and an areal density of 50–160 g / m³. 2 In this embodiment, if the aluminum foil layer 4 is too thin, it will be fragile; if it is too thick, it will be too rigid and difficult to bond during forming. Therefore, the film thickness is approximately 20–60 mm, preferably 20 mm, and the areal density is approximately 50–160 g / m³. 2 65g / m 2 .

[0028] In some embodiments, aluminum foil may be replaced by other film materials such as PE film.

[0029] See Figure 1 As shown, in some embodiments, a nonwoven fabric layer 5 is provided on the side of the second aluminum foil layer 4 opposite to the glass fiber cotton layer 1, and the areal density of the nonwoven fabric layer 5 is 130±40 g / m². 2 In this embodiment, the nonwoven fabric layer is made of polyester fiber (also known as PET fiber, polyester) or polypropylene fiber (also known as PP fiber, polypropylene), with a thickness of approximately 1.3 mm and an areal density of 130±40 g / m³. 2 It can constrain the stability of the double aluminum foil cavity structure and has a certain aesthetic appeal.

[0030] See Figure 1 As shown, in some embodiments, the composite felt layer 3 is formed by needle punching a blend of pre-oxidized filament fiber and thermoplastic organic fiber, with a ratio of 80%:20% to 40%:60%. In this embodiment, the composite felt layer 3 can be formed by needle punching a blend of pre-oxidized filament fiber and thermoplastic organic fiber (which can be polypropylene fiber or polyester fiber, etc.) in a certain proportion. The appropriate blending ratio of pre-oxidized filament fiber and thermoplastic fiber is 80%:20% to 40%:60% (if there is too little thermoplastic fiber, the adhesion to the aluminum foil will be poor; conversely, it will not be easy to achieve a semi-rigid and semi-fluffy state). The content is gradually increased from the engine-facing side to the other side to ensure that the fibers exposed on the outside after molding have a certain fluffiness, the whole has sufficient rigidity, and has adhesion to the aluminum foil bonding surface.

[0031] In some embodiments, the free thickness of the composite felt layer 3 can be 3 mm to 8 mm (preferably 5 mm), and the areal density is about 200 to 520 g / m³. 2 (Preferred 260g / m) 2 The pre-oxidized fiber has non-combustible properties, providing flame retardancy for the engine, and its fiber state exhibits good sound absorption performance. The thermoplastic organic fiber has melt-plastic properties at high temperatures, serving as a rigid layer and bonding aluminum foil. Under hot pressing, the internal thermoplastic fiber of the pre-oxidized fiber composite felt layer melts and combines with some of the pre-oxidized fiber to form a relatively dense layer. After cooling and shaping, it forms an integral structure with other layers, providing sufficient component rigidity while also providing sound absorption and good sound and heat insulation effects. After molding, its semi-rigid and semi-fluffy shape also provides shock absorption. Furthermore, the pre-oxidized fiber composite felt partially replaces the amount of glass fiber wool, resulting in weight reduction.

[0032] See Figure 1 As shown, in some embodiments, the composite felt layer 3 includes at least one of pre-oxidized fiber composite felt, carbon fiber composite felt, and thermoplastic organic fiber composite felt. In this embodiment, the pre-oxidized fiber composite felt layer can be other composite felts such as carbon fiber composite felt, or it can be composed of one or more composite felts of pre-oxidized fiber, carbon fiber, and thermoplastic organic fiber, which can more effectively improve the heat insulation effect and the sound absorption and insulation effect in different frequency bands.

[0033] Similarly, the nonwoven layer 5 can also be other composite felts such as pre-oxidized fiber composite felt or carbon fiber composite felt, or composed of one or more composite felts of pre-oxidized fiber, carbon fiber, and thermoplastic organic fiber, to further improve heat insulation and sound absorption performance.

[0034] Similarly, glass fiber wool layer 1 can also be replaced by organic fiber felts or composite felts such as pre-oxidized fiber felt or carbon fiber felt, which is more environmentally friendly and lightweight.

[0035] See Figure 1 As shown, in some embodiments, the content of the composite felt layer 3 gradually increases from the side away from the first aluminum foil layer 2 to the side closer to the first aluminum foil layer 2. In this embodiment, by gradually increasing the content of the composite felt layer 3 from the side facing the engine to the other side, it is ensured that the fibers exposed to the outside after molding have a certain degree of fluffiness, the whole has sufficient rigidity, and has adhesion to the aluminum foil bonding surface.

[0036] See Figure 1 As shown, in some embodiments, the thickness of the glass fiber cotton layer 1 is 5–25 mm, and the areal density is 350–1600 g / m³. 2 In this embodiment, the fibers of the glass fiber cotton layer 1 contain a small amount of thermosetting resin adhesive, which can play a role in shaping and bonding the aluminum foil during hot pressing. The free thickness of the glass fiber cotton layer 1 is 5-25mm (preferably 15mm), and the areal density is 350-1600g / m³. 2 (preferred 940g / m) 2 ).

[0037] In some embodiments, the thickness requirements of different parts of the product vary, and the fineness of the glass fiber cotton layup is slightly different in actual operation. The pre-oxidized fiber composite felt, non-woven fabric and aluminum foil are evenly distributed in the same part, and the product thickness is achieved by adjusting the mold.

[0038] In some embodiments, the bonding between other layers, namely the nonwoven fabric and the aluminum foil, and the pre-oxidized fiber composite felt and the aluminum foil, is done without adhesive. It mainly relies on the micro-melting of the nonwoven fabric surface at high temperature during molding and the melting of the polypropylene fibers in the pre-oxidized fiber composite felt, which then bond to the aluminum foil under pressure.

[0039] See Figure 1As shown, this embodiment of the invention also provides a method for manufacturing an automotive underbody heat insulation pad, which may include the following steps: laying nonwoven fabric layer 5 → second aluminum foil layer 4 → glass fiber cotton layer 1 → first aluminum foil layer 2 → composite felt layer 3 sequentially on a mold, so that the nonwoven fabric layer 5, second aluminum foil layer 4, glass fiber cotton layer 1, first aluminum foil layer 2 and composite felt layer 3 are stacked sequentially; closing the mold, heating the material from both top and bottom simultaneously; applying pressure to thermally bond and shape each layer to form an automotive underbody heat insulation pad, wherein the side of the composite felt layer 3 facing away from the first aluminum foil layer 2 is fluffy. By pre-laying the composite felt layer 3, first aluminum foil layer 2, glass fiber cotton layer 1, second aluminum foil layer 4 and nonwoven fabric layer 5 in a mold and then heating and shaping them into an integrated structure, the underbody heat insulation pad obtained, at the same areal density, not only improves the heat insulation performance, but also has better sound absorption and insulation effects.

[0040] The specific implementation process is as follows:

[0041] (1) Cutting: Cut each layer of material to the required size according to the product size and shape of the heat insulation pad.

[0042] (2) Laying out layers: Lay the layers on the mold in the following order: “non-woven fabric layer 5 → second aluminum foil layer 4 → glass fiber cotton layer 1 → first aluminum foil layer 2 → composite felt layer 3”.

[0043] (3) Heating: Close the mold and preheat the material from both the top and bottom sides simultaneously. Set the temperature of the upper and lower molds to 235℃ and the heating time to 30min.

[0044] (4) Pressing and punching: After heating, the temperature of the upper and lower molds is still maintained at 235℃. Then, 16 MPa pressure is applied for pressing, and the pressure holding time is 5 minutes, so that each layer is thermally bonded and plasticized into an integrated structure. After shaping, the excess parts such as mounting holes are punched out in the mold.

[0045] (5) Trimming: After opening the mold and taking out the pre-made product, the final step is to trim the rough edges.

[0046] The present invention, specifically the automotive underbody heat insulation pad and its manufacturing method, will be further described below with reference to specific embodiments.

[0047] Example 1:

[0048] A novel composite material, consisting of a pre-oxidized fiber composite felt layer, an aluminum foil layer, a glass fiber cotton layer, another aluminum foil layer, and a non-woven fabric layer (facing the cab) arranged sequentially from the engine to the cab, is characterized by having a "reflective layer structure formed by the pre-oxidized fiber composite felt layer and the first aluminum foil layer" and "a layer of aluminum foil adhered to each side of the glass fiber cotton layer, forming a double aluminum foil cavity structure with the glass fiber cotton layer itself." The material is pre-laid into a mold, heated, and then molded into a single unit, thermally bonding and shaping each layer to produce a heat insulation pad for the cab of a commercial vehicle. The specific method is as follows:

[0049] The novel structural composite material combination in Example 1 is as follows:

[0050] The pre-oxidized fiber composite felt layer is made of pre-oxidized fiber and polypropylene fiber blended and needle-punched in a 70%:30% ratio, with a free thickness of approximately (5±1) mm and a surface density of approximately 260 g / m³. 2 The polypropylene fiber content gradually increases from the engine-facing side to the other side, ensuring that the exposed fibers after molding have a certain degree of fluffiness, sufficient overall rigidity, and adhesion to the aluminum foil bonding surface.

[0051] The aluminum foil layer is a non-porous aluminum foil with a film thickness of approximately 20 μm and an areal density of 65 g / m³. 2 .

[0052] The fiberglass wool layer contains a small amount of thermosetting resin adhesive on the fibers. During hot pressing, it serves to shape and bond the aluminum foil. The free thickness is approximately 15mm, and the areal density is 940g / m³. 2 .

[0053] The non-woven fabric layer is made of polypropylene fiber non-woven fabric, with a thickness of approximately 1.3 mm and a surface density of 130 g / m³. 2 It constrains the stability of the double aluminum foil cavity structure and has a certain aesthetic appeal.

[0054] The specific process of Example 1 is as follows:

[0055] (1) Cutting: Cut each layer of material to the required size according to the product size and shape of the heat insulation pad.

[0056] (2) Laying out layers: Lay the non-woven fabric layer → second aluminum foil layer → glass fiber cotton layer → first aluminum foil layer → pre-oxidized fiber composite felt layer on the mold in sequence.

[0057] (3) Heating: Close the mold and preheat the material from both the top and bottom sides simultaneously. The temperature of the upper and lower molds is set to 235℃ and the heating time is 30min.

[0058] (4) Pressing and punching: After heating, the temperature of the upper and lower molds is still maintained at 235℃. Then, 16 MPa pressure is applied for pressing, and the pressure holding time is 5 minutes, so that each layer is thermally bonded and plasticized into an integrated structure. After shaping, the excess parts such as mounting holes are punched out in the mold.

[0059] (5) Trimming: After opening the mold and taking out the pre-made product, the final step is to trim the rough edges.

[0060] In this embodiment, the actual measured thickness of the finished product of the commercial vehicle's underbody heat insulation pad is 6mm to 15mm (excluding the thinnest and final parts at the edge sealing area), and the areal density is approximately 1400 to 1650 g / m³. 2 (Theoretical value 1560g / m³) 2 The component weighs 2.83 kg. The heat insulation temperature measured under the standard test thermal environment of 80℃ is △T=54.0℃. The sound insulation range of the standing wave tube method (100Hz~5000Hz, the same below) is 11.8~42.7dB, with an average sound insulation of 30.4dB. The stiffness meets the technical requirements of the heat insulation pad under commercial vehicles.

[0061] The aforementioned commercial vehicle under-heat insulation pad, with the same surface density, not only improves heat insulation but also significantly enhances sound absorption and insulation.

[0062] Example 2:

[0063] Based on Example 1, the material combination was modified as follows: 1) The non-woven fabric layer was replaced with a carbon fiber composite felt layer; 2) The areal density of the glass fiber cotton was 780 g / m³. 2 ; and the resulting changes.

[0064] The specific description is as follows:

[0065] A novel composite material, consisting of a pre-oxidized fiber composite felt layer, an aluminum foil layer, a glass fiber cotton layer, an aluminum foil layer, and a carbon fiber composite felt layer (facing the cab) arranged sequentially from the engine to the cab, is characterized by having a "reflective layer structure formed by the pre-oxidized fiber composite felt and the first aluminum foil layer" and "a layer of aluminum foil adhered to each side of the glass fiber cotton, which, together with the glass fiber cotton layer itself, forms a double aluminum foil cavity structure." The non-woven fabric layer on the back is replaced with a carbon fiber composite felt layer to further improve rigidity, heat insulation, and sound absorption and insulation performance. The material is pre-laid in a mold, heated, and then molded into an integrated unit, allowing each layer to be thermally bonded and shaped. This process produces a heat insulation pad for the cab of a commercial vehicle. The specific method is as follows.

[0066] Example 2 Material Combination Description:

[0067] The pre-oxidized fiber composite felt layer is made of pre-oxidized fiber and polypropylene fiber blended and needle-punched in a 70%:30% ratio, with a free thickness of approximately (5±1) mm and a surface density of approximately 260 g / m³. 2The polypropylene fiber content gradually increases from the engine-facing side to the other side, ensuring that the exposed fibers after molding have a certain degree of fluffiness, sufficient overall rigidity, and adhesion to the aluminum foil bonding surface.

[0068] The aluminum foil layer is a non-porous aluminum foil with a film thickness of approximately 20 μm and an areal density of 65 g / m³. 2 .

[0069] The fiberglass wool layer contains a small amount of thermosetting resin adhesive on the fibers. During hot pressing, it can serve to shape and bond the aluminum foil. The free thickness is approximately 12mm, and the areal density is 780g / m³. 2 .

[0070] The carbon fiber composite felt layer is made of recycled carbon fiber short filaments and polypropylene fibers blended and needle-punched in a 40%:60% ratio, with a free thickness of approximately (4±1) mm and a surface density of 200 g / m³. 2 The polypropylene fiber content gradually increases from the side facing the cab to the other side, ensuring that the fibers exposed on the outside after molding have a certain degree of fluffiness, the whole has sufficient rigidity, and the bonding surface with aluminum foil has adhesiveness, constraining the stability of the double aluminum foil cavity structure and having a certain degree of aesthetics, while further improving rigidity, heat insulation and sound absorption performance.

[0071] The specific process of Example 2 is as follows:

[0072] (1) Cutting: Cut each layer of material to the required size according to the product size and shape of the heat insulation pad.

[0073] (2) Laying out layers: Lay the non-woven fabric layer → second aluminum foil layer → glass fiber cotton layer → first aluminum foil layer → pre-oxidized fiber composite felt layer on the mold in sequence.

[0074] (3) Heating: Close the mold and preheat the material from both the top and bottom sides simultaneously. The temperature of the upper and lower molds is set to 235℃ and the heating time is 30min.

[0075] (4) Pressing and punching: After heating, the temperature of the upper and lower molds is still maintained at 235℃. Then, 16 MPa pressure is applied for pressing, and the pressure holding time is 5 minutes, so that each layer is thermally bonded and plasticized into an integrated structure. After shaping, the excess parts such as mounting holes are punched out in the mold.

[0076] (5) Trimming: After opening the mold and taking out the pre-made product, the final step is to trim the rough edges.

[0077] In this embodiment, the actual measured thickness of the finished product of the commercial vehicle's underbody heat insulation pad is 6mm to 15mm (excluding the thinnest and final parts at the edge sealing area), and the areal density is approximately 1360 to 1530 g / m³. 2 (Theoretical value 1470g / m³) 2The component weighs 2.76 kg. The heat insulation temperature measured under the standard test thermal environment of 80℃ is △T=54.8℃. The sound insulation range of the standing wave tube method (100Hz~5000Hz, the same below) is 12.5~45.3dB, with an average sound insulation of 31.4dB. The stiffness meets the technical requirements of the heat insulation pad under commercial vehicles.

[0078] The aforementioned commercial vehicle underbody heat insulation pads, with the same surface density, further enhance heat insulation and sound absorption / insulation effects, but at the cost of increased costs.

[0079] Comparative Example 1:

[0080] Example 1: Reduce the first aluminum foil layer.

[0081] Comparative Example 2

[0082] The existing technology uses a structure of "aluminum foil + glass fiber wool + waste felt", with a main body thickness of 5mm to 14mm and a surface density of approximately 1400 to 1600 g / m³. 2 .

[0083] Comparative Example 3

[0084] The existing technology uses a structure of "non-woven fabric + glass fiber wool + non-woven fabric", with a main body thickness of 13mm to 22mm and a surface density of approximately 2200 to 2600 g / m³. 2 .

[0085] The test data of implementation cases 1 and 2 and comparative examples 1 and 3, which are samples of similar thickness or the same part of the parts, are shown in Tables 1 and 2 below:

[0086] Table 1 shows the thermal insulation measured under a standard test thermal environment at 80℃.

[0087] Implementation Case 1 <![CDATA[1563g / m 2 ]]> 15mm 54.0℃ Implementation Case 2 <![CDATA[1490g / m 2 ]]> 15mm 54.8℃ Comparison 1 <![CDATA[1510g / m 2 ]]> 15mm 52.5℃ Comparison 2 <![CDATA[1534g / m 2 ]]> 14mm 51.1℃ Comparison 3 <![CDATA[2351g / m 2 ]]> 22mm 53.6℃

[0088] Table 2

[0089]

[0090]

[0091] Therefore, it can be seen that the lower heat insulation pad provided in the embodiments of the present invention significantly improves the sound insulation effect while achieving a better heat insulation effect.

[0092] The principle of the automotive underbody heat insulation pad and its manufacturing method provided in this invention is as follows:

[0093] A novel composite material, arranged sequentially from the engine to the cab, consists of a composite felt layer 3 (facing the engine), a first aluminum foil layer 2, a glass fiber cotton layer 1, a second aluminum foil layer 4, and a non-woven fabric layer 5 (facing the cab). Its key features include a reflective layer structure formed by the composite felt layer 3 and the first aluminum foil layer 2, and a double aluminum foil cavity structure formed by two aluminum foil layers adhered to each side of the glass fiber cotton layer 1. The main interlayer bonding, namely between the non-woven fabric layer 5 and the aluminum foil layer, and between the composite felt layer 3 and the aluminum foil layer, relies primarily on the micro-melting of the non-woven fabric surface during molding at high temperatures, and the bonding of the melted polypropylene fibers in the pre-oxidized composite felt to the aluminum foil under pressure. Utilizing the mirror-like properties of the uneven aluminum foil and its high reflectivity for sound and heat, as well as the characteristics of glass fiber, the partially fused and bonded composite felt layer 3 forms a reflective layer structure with the first aluminum foil layer 2. A layer of aluminum foil is adhered to each side of the glass fiber cotton layer 1 to form a double aluminum foil reflective cavity structure. The two structures improve the heat insulation and sound insulation performance of the composite material, greatly reduce the heat and noise transmission rate, and play a blocking role.

[0094] When engine noise and radiant heat pass through the pre-oxidized fiber composite felt, the noise and radiant heat are reflected in the first aluminum foil layer. They undergo initial attenuation in the pre-oxidized fiber, which still maintains a certain degree of fluffiness and has a sound-absorbing effect, and in the polypropylene, which has a sound-insulating effect, after being fused together. The penetrating noise and heat enter the double aluminum foil reflective cavity structure, where they are reflected back and forth between the two aluminum foil layers. They then enter the glass fiber wool and are continuously transmitted, vibrated, adhered, and scattered, thus attenuating. Moreover, the glass fiber wool itself has excellent heat insulation properties. The noise and heat are greatly attenuated in this structure, significantly improving the sound insulation effect while achieving a better heat insulation effect.

[0095] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0096] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0097] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A car underbody heat insulation pad, characterized in that, It includes: Glass fiber cotton layer (1); The first aluminum foil layer (2) is disposed on one side of the glass fiber cotton layer (1); The composite felt layer (3) is bonded to the side of the first aluminum foil layer (2) away from the glass fiber cotton layer (1), and the side of the composite felt layer (3) away from the first aluminum foil layer (2) is fluffy. The glass fiber cotton layer (1) has a second aluminum foil layer (4) on the side opposite to the first aluminum foil layer (2); The second aluminum foil layer (4) has a non-woven fabric layer (5) on the side opposite to the glass fiber cotton layer (1); The composite felt layer (3) is a pre-oxidized fiber composite felt layer, which is made by needle punching a blend of pre-oxidized fiber and polypropylene fiber in a ratio of 70%:30%, with a free thickness of (5±1) mm and a surface density of 260 g / m³. 2 ; The polypropylene fiber content in the composite felt layer (3) gradually increases from the engine-facing side to the other side; The first aluminum foil layer (2) and the second aluminum foil layer (4) are both non-porous aluminum foils with a film thickness of 20 μm and an areal density of 65 g / m³. 2 ; The glass fiber cotton layer (1) has a free thickness of 12 mm and a surface density of 780 g / m³. 2 ; The nonwoven fabric layer (5) is a carbon fiber composite felt layer, which is made by needle punching recycled carbon fiber short filaments and polypropylene fibers in a ratio of 40%:60%, with a free thickness of (4±1) mm and a surface density of 200 g / m³. 2 The polypropylene fiber content in the carbon fiber composite felt layer gradually increases from the side facing the cab to the other side; The manufacturing method of the automotive underbody heat insulation pad includes: The carbon fiber composite felt layer → second aluminum foil layer (4) → glass fiber cotton layer (1) → first aluminum foil layer (2) → pre-oxidized fiber composite felt layer are laid on the mold in sequence; The mold is closed, and the material is preheated from both the top and bottom sides simultaneously. The temperature of the upper and lower molds is set to 235℃, and the heating time is 30 minutes. After heating, the temperature of the upper and lower molds is maintained at 235℃. Then, a pressure of 16 MPa is applied for pressing, and the pressure holding time is 5 minutes, so that the layers are thermally bonded and plasticized into an integrated structure. After shaping, the excess parts of each mounting hole are punched out in the mold.

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