Seal for body panel reinforcement

Abstract

A seal for vehicle body panel reinforcement includes a seal layer on a vehicle body panel and a skin disposed on the seal layer and comprising a glass fiber reinforced plastic.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0002474, filed with the Korean Intellectual Property Office on January 8, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to a seal for reinforcing body panels, used to enhance the rigidity of body panels (e.g., vehicle doors and rear roof side panels). Background Technology

[0004] The main body of a vehicle can be broadly divided into the body, the exterior, and the interior. The body, which forms the vehicle's exterior, can include outer panels, inner panels, reinforcing panels, and a subframe. Within the body, the side panels, door panels, floor, and roof, which form the central body, constitute the passenger seating space.

[0005] Seals used to enhance the rigidity of the vehicle body can be installed between the outer and inner panels.

[0006] When the flexural strength of the seals used to enhance the rigidity of the vehicle body is low, the rigidity is weak; when the flexural strength is high, the hardness increases, resulting in dents on the outer panel. Summary of the Invention

[0007] One embodiment provides a seal for reinforcing body panels that can further improve rigidity without creating dents in the outer panel, thereby reducing panel thickness and minimizing the number of added components / supports to reduce costs.

[0008] According to one embodiment, the seal for reinforcing body panels includes a sealing layer located on the body panel and a surface layer disposed on the sealing layer and comprising glass fiber reinforced plastic.

[0009] The glass fibers in glass fiber reinforced plastics can be from about 30 denier to about 60 denier.

[0010] The density (warp and weft density) of glass fibers in glass fiber reinforced plastics can be from about 60 to about 80 filaments.

[0011] Glass fiber reinforced plastics may contain glass fibers and a matrix resin bonded to the glass fibers.

[0012] Based on the total weight of the matrix resin, the matrix resin may contain about 50% to about 60% by weight of bisphenol A epoxy resin, about 30% to about 40% by weight of polyamide, and 5% to 10% by weight of urea.

[0013] The thickness of the surface layer can be from approximately 0.45 mm to approximately 0.75 mm.

[0014] The thickness of the sealing layer can be from about 1.0 mm to about 1.5 mm.

[0015] The sealing layer may comprise about 30% to about 50% by weight of epoxy resin, about 3% to about 10% by weight of curing agent, about 1% to about 5% by weight of tackifier, about 13% to about 35% by weight of filler, about 1% to about 10% by weight of hygroscopic agent, about 3% to about 5% by weight of flow inhibitor and about 1% to about 2% by weight of stabilizer.

[0016] The seals used for reinforcing body panels according to the implementation plan can further improve rigidity without creating dents in the outer panels, thereby reducing panel thickness and minimizing the number of added components / supports, thus reducing costs. Attached Figure Description

[0017] Figure 1 A cross-sectional view of a seal for reinforcing body panels according to one embodiment is shown schematically.

[0018] Figure 2 A plan view showing the specimen used to measure the low-temperature bending resistance of seals used for reinforcing body panels. Detailed Implementation

[0019] The advantages and features of this application, as well as the methods of implementing this application, will become apparent from the embodiments described below with reference to the accompanying drawings. However, the embodiments should not be construed as limiting oneself to the embodiments described herein. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. Terms as defined in general dictionaries should not be interpreted ideally or exaggeratedly unless explicitly defined otherwise. Furthermore, unless explicitly stated to the contrary, the terms “comprising” and variations such as “including” or “containing” should be understood to mean including the stated elements, but not excluding any other elements.

[0020] Furthermore, unless otherwise stated, the singular includes the plural.

[0021] In the accompanying drawings, the thickness of layers, films, sheets, areas, etc., is exaggerated for clarity. Throughout the specification, the same reference numerals denote the same elements.

[0022] It should be understood that when an element (such as a layer, film, region, or substrate) is referred to as being "on" another element, it may be directly on the other element or there may be an intervening element present. Conversely, when an element is referred to as being "directly on another element," there is no intervening element present.

[0023] A seal for reinforcing body panels according to one embodiment includes a sealing layer on a body panel and a surface layer on the sealing layer.

[0024] Figure 1 A cross-sectional view of a seal for reinforcing body panels according to one embodiment is shown schematically. (Reference) Figure 1 It specifically describes seals used for reinforcing body panels.

[0025] The vehicle body can be formed by combining outer and inner panels. A seal 10 for reinforcing the body panels can be disposed between the outer and inner panels, or on the inner surface of the outer panel, to enhance the rigidity of the body and improve vibration damping properties.

[0026] The seal 10 for reinforcing body panels can be disposed on the panel 100 (e.g., an outer panel or an inner panel). The panel 100 can be, for example, a steel plate, but a panel 100 of any material can be used as long as it is usable as a body panel, and this application is not particularly limited thereto.

[0027] The sealing layer 200 can be manufactured by curing a composition for sealing containing epoxy resin.

[0028] Epoxy resin is used to improve the hardness and strength of the sealing layer 200. The composition used for the seal may contain, for example, bisphenol A epoxy resin as the epoxy resin.

[0029] Based on the total weight of the composition used for sealing, epoxy resin may be included in an amount of about 30% to about 50% by weight, for example, about 30% to about 40% by weight, about 40% to about 50% by weight, or about 35% to about 45% by weight. When the epoxy resin content is less than about 30% by weight, the shear strength may be reduced, and when it exceeds about 50% by weight, the discharge properties may be reduced, and indentations may occur in the plate 100.

[0030] The composition for the seal may contain a curing agent for curing epoxy resin. For example, the curing agent for curing epoxy resin may be dicyandiamide. Dicyandiamide can provide adhesion between the seal layer 200 and the plate 100.

[0031] Based on the total weight of the sealing composition, the curing agent may be included in an amount from about 3% to about 10% by weight, for example, from about 6% to about 10% by weight or from about 6% to about 7% by weight. When the content of the curing agent is less than about 3% by weight, the epoxy resin may not be cured, thereby reducing shear adhesion, while when it exceeds about 7% by weight, the epoxy resin may be over-cured and the impact resistance may be reduced.

[0032] The composition for the seal may also contain an tackifier that bonds the sealing layer 200 to the plate 100. The tackifier may be, for example, a silane. Based on the total weight of the composition for the seal, the tackifier may be included in an amount from about 1% to about 5% by weight, for example, from about 3% to about 5% by weight. When the tackifier content is less than about 1% by weight, the adhesion to the plate 100 may be poor, while when the tackifier content is greater than about 5% by weight, the cohesive force between the tackifiers may be reduced.

[0033] The composition for use in sealing elements may also contain calcium carbonate as a filler. The filler can impart filling properties, spraying properties, and flowability to the sealing composition. Based on the total weight of the composition for use in sealing elements, the filler may be included in an amount from about 13% by weight to about 35% by weight, for example, from about 17% by weight to about 35% by weight or from about 25% by weight to about 35% by weight. When the filler content is less than about 13% by weight, the spraying properties and flowability (processability) may decrease, and if it exceeds about 35% by weight, the shear strength may decrease.

[0034] The composition for use in sealing elements may also contain a hygroscopic agent for removing moisture from the composition. The hygroscopic agent may be, for example, calcium oxide (CaO). Based on the total weight of the composition for use in sealing elements, the hygroscopic agent may be included in an amount from about 1% to about 10% by weight, for example, from about 2% to about 10% by weight or from about 5% to about 10% by weight. When the content of the hygroscopic agent is less than about 1% by weight, moisture may not be sufficiently removed, and the composition for use in sealing elements may swell due to moisture; while when it exceeds about 10% by weight, adhesiveness and shear strength may decrease.

[0035] The composition for use in sealing components may also contain a flow inhibitor to prevent flow of the composition. The flow inhibitor may be, for example, bentonite. Based on the total weight of the composition for use in sealing components, the flow inhibitor may be included in an amount from about 3% to about 5% by weight. When the content of the flow inhibitor is less than about 3% by weight, the flowability may decrease, while when it exceeds about 5% by weight, the adhesion may decrease.

[0036] The composition for use in sealing may also contain a stabilizer for stabilizing heat resistance. The stabilizer may be, for example, tin oxide. Based on the total weight of the composition for use in sealing, the stabilizer may be included in an amount from about 1% to about 2% by weight. When the stabilizer content is less than about 1% by weight, it may be difficult to ensure sufficient heat resistance, while when it exceeds about 2% by weight, adhesion may decrease.

[0037] On the other hand, since the thickness of the sheet metal 100 has been reduced to lighten the vehicle body, increased rigidity is still required. However, when the rigidity of the sealing layer 200 is increased, dents may appear on the outer panel. Therefore, by providing a surface layer 300 on the sealing layer 200, rigidity can be further improved without causing dents on the outer panel.

[0038] In addition, the surface layer 300 can enhance the rigidity of the plate 100 without adding components / supports, and the thickness of the sealing layer 200 can be adjusted downwards due to the installation of the surface layer 300, thereby reducing costs.

[0039] Therefore, the thickness of the sealing layer 200 can be from about 1.0 mm to about 1.5 mm. When the thickness of the sealing layer is less than about 1.0 mm, the damping performance may be less than about 0.02 (0.02 is the required value), while when the thickness of the sealing layer 200 exceeds about 1.5 mm, dents may occur on the outer panel of the vehicle body.

[0040] The thickness of the surface layer 300 can be from about 0.45 mm to about 0.75 mm. When the thickness of the surface layer 300 is less than about 0.45 mm, the flexural strength may decrease, while when it exceeds about 0.75 mm, the vibration damping properties may not meet the requirements.

[0041] The surface layer 300 may comprise glass fiber reinforced plastic. The glass fiber reinforced plastic may comprise glass fibers and a matrix resin bonded to the glass fibers.

[0042] In this case, the vibration damping properties of the surface layer 300 are affected not only by the thickness of the surface layer 300, but also by the fineness and density of the glass fibers constituting the surface layer 300.

[0043] The fineness of the glass fiber can be from about 30 denier to about 60 denier, for example, from about 40 denier to about 50 denier. When the fineness of the glass fiber is less than about 30 denier, the flexural strength of the seal 10 used for reinforcing body panels may be less than 20 kgf, which may not meet the requirements. When it exceeds about 60 denier, the damping properties may be about 0.01 (less than the required value of 0.02). Here, fineness (denier) refers to the weight of 9000 meters of yarn (g / 9000m = D).

[0044] Furthermore, the density (warp and weft density) of the glass fiber can be from approximately 60 to approximately 80 filaments, for example, from approximately 70 to approximately 80 filaments. When the density of the glass fiber is less than approximately 60 filaments, the flexural strength of the seal 10 used for reinforcing body panels may be less than 20 kgf, which may not meet the requirements. When it exceeds approximately 80 filaments, the vibration damping properties may be approximately 0.01 (less than the required value of 0.02). Here, density (warp and weft density) refers to the number of weft yarns (horizontal filaments) and warp yarns (longitudinal filaments) woven per square inch.

[0045] The surface layer 300 can be manufactured by impregnating glass fiber into a matrix resin and then curing it. Therefore, the seal 10 used for body panel reinforcement does not produce problems of rusting and separation at the boundary.

[0046] Based on the total weight of the matrix resin, the matrix resin may contain about 50% to about 60% by weight of bisphenol A epoxy resin, about 30% to about 40% by weight of polyamide, and about 5% to about 10% by weight of urea.

[0047] Bisphenol A epoxy resin imparts fundamental physical properties to the matrix resin. When the content of bisphenol A epoxy resin is less than about 50% by weight, the hardness and adhesion of the matrix resin may decrease, and when it exceeds about 60% by weight, the hardness of the matrix resin increases and the impact resistance may decrease.

[0048] Polyamides can be used to cure epoxy resins. When the polyamide content is less than about 30% by weight, the matrix resin may not cure, and when it exceeds about 40% by weight, the matrix resin may over-cur.

[0049] Urea can be used to shorten the curing time of the matrix resin. When the urea content is less than about 5% by weight, the curing time may be too long, while when it exceeds about 10% by weight, the adhesive properties of the matrix resin may deteriorate.

[0050] The following illustrates specific embodiments of this application. However, the embodiments described below are for illustrative purposes only and do not limit the scope of this application.

[0051] Methods for evaluating physical properties

[0052] (1) Shear strength (MPa): A sealant composition was applied to a 100×25×1.6mm steel plate, and 12.5mm wide tape was applied to the ends. An identical steel plate was then stacked on top, overlapping only the areas coated with the sealant composition. The plates were then secured with clamps, and the sealant composition was subsequently cured. The stacked steel plates were left to stand at room temperature for 1 hour and then stretched at 5mm / min in a tensile testing machine to measure the maximum load.

[0053] (2) Flexural strength (kgf): Samples were prepared by coating and curing a 1.5 mm thick composition for sealing on a 25×150×0.75 mm steel plate, and then the samples were left to stand at room temperature for 1 hour or longer, and a load was applied at 5 mm / min to measure the flexural strength (kgf).

[0054] (3) Low-temperature bending resistance (mm): such as Figure 2 As shown, a sealing composition (S) was applied to the center of a 300×300×0.75mm steel sheet (T) in a dimension of 150×80×1.5mm, followed by heating and curing. The coated sheet was left to stand at room temperature for 1 hour or longer, and then at -30°C for 30 minutes, before being measured at -30°C. Figure 2 The deformation at the locations shown (P1 to P8) is used to determine the maximum value of the deformation as the outer plate dent property.

[0055] (4) Vibration reduction properties:

[0056] According to theoretical measurement methods, the smoothness of the slope (peak) at the secondary resonance point can be measured. When the composition has excellent dustproof properties, the amplitude at the resonance point decreases, and the slope becomes smoother. In other words, dustproof performance can be measured by measuring either the slope or the amplitude at the resonance point.

[0057] -Damping loss coefficient = Δf / f

[0058] In the above formula, f is the frequency of the second resonance point, and Δf is the frequency difference between the interval and the interval with an amplitude difference of 3dB from the second resonance point.

[0059] In addition, according to the measurement method of the equipment used, a sample of a 1.5 mm thick seal for body panel reinforcement was formed on a 20 mm × 200 mm steel plate, vibrated in an Exciter Tranducer, and then the amplitude was measured in a Motion Tranducer.

[0060] An analytical plot was obtained by analyzing the amplitude (dB) as a function of frequency (Hz) using PC. Similar to the theoretical measurement method, the frequency (f) at the secondary resonance point and the frequency difference (Δf) between the frequency (f) at the secondary resonance point and the frequencies in the interval 3 dB away from the secondary resonance point were calculated.

[0061] To achieve the objectives of this application, the target values ​​for the shear adhesion, flexural strength, low-temperature bending resistance and vibration damping properties of the seals used for body panel reinforcement are shown in Table 1.

[0062] Table 1

[0063] Test Project Target value Shear adhesion 8MPa or higher Flexural strength 20kgf or higher Low temperature bending resistance 1.7mm or smaller Vibration reduction properties 0.02 or higher

[0064] Experimental Example 1: Experiment on Surface Materials

[0065] When glass fiber (glass wool) and glass fiber reinforced plastic (GFRP) were used as the surface layer, the flexural strength, low-temperature bending resistance and vibration damping properties were evaluated, and the results are shown in Table 2.

[0066] Table 2

[0067]

[0068]

[0069] Compared to Comparative Example 1-1, Comparative Example 1-2 has an increased thickness. Referring to Comparative Examples 1-1 and 1-2, the increased thickness of the seal improves flexural strength and thus enhances rigidity; however, it reduces low-temperature bending resistance, which may lead to dents in the vehicle body.

[0070] Therefore, since seals with increased thickness cannot be applied to vehicles alone, a surface layer was introduced.

[0071] Comparative Examples 1-3 and 1-4 show the evaluation results using glass wool as the surface material, while Comparative Examples 1-5 and 1-6 show the evaluation results using GFRP as the surface material. Referring to Comparative Examples 1-3 and 1-4, the highest flexural strength was obtained when 0.32 mm thick GFRP was applied, which is closest to the target value of 20 kgf. Therefore, GFRP is more advantageous than glass wool in achieving the target flexural strength.

[0072] Experimental Example 2: Surface Thickness Experiment

[0073] When glass fiber reinforced plastic (GFRP) is used as the surface layer, its flexural strength, low-temperature bending resistance and vibration damping properties are evaluated by varying its thickness, and the results are shown in Table 3.

[0074] Table 3

[0075]

[0076] Referring to Table 3, the flexural strength increases with the increase of surface thickness, but it is difficult to find a trend related to the vibration reduction properties.

[0077] The surface layer exhibits sufficient damping properties at thicknesses of 0.45 mm and 0.75 mm (0.02), but insufficient damping properties at thicknesses of 0.60 mm and 0.90 mm (0.01, which does not meet the target value).

[0078] Therefore, the thickness of the surface layer alone cannot simultaneously improve flexural strength, low-temperature bending resistance, and vibration damping properties.

[0079] Experimental Example 3: Experiment on Surface Fineness and Density

[0080] When glass fiber reinforced plastic (GFRP) is used as the surface layer, the flexural strength, low-temperature bending resistance and vibration damping properties are evaluated by changing the fineness and density of the glass fibers as shown in Table 4, and the results are shown in Table 5.

[0081] Table 4

[0082]

[0083] Table 5

[0084]

[0085]

[0086] Referring to Tables 4 and 5, when the glass fiber fineness is 30 denier or less, the flexural strength is less than 20 kgf (not meeting the requirements). However, when the glass fiber fineness is 60 denier or higher, the vibration damping property is 0.01, which does not reach the target value of 0.02.

[0087] Furthermore, when the density of glass fiber is 60 filaments or less, the flexural strength is 20 kgf or less (which does not meet the requirements), but when the density of glass fiber is 90 filaments or more, the vibration damping property is 0.01, which does not meet the target value.

[0088] Therefore, the vibration damping properties of the seal are affected by the fineness and density of the glass fibers that make up the surface layer, as well as the thickness of the surface layer.

[0089] Although this application has been described in conjunction with embodiments now considered practical, it should be understood that this application is not limited to the disclosed embodiments. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the claims.

Claims

1. A seal for reinforcing body panels, the seal comprising: Sealing layer located on body panels; and A surface layer disposed on the sealing layer, the surface layer comprising glass fiber reinforced plastic; Among them, the fineness of the glass fibers in glass fiber reinforced plastics is in the range of 40 denier to 50 denier. The plate is a steel plate. The density of glass fibers in glass fiber reinforced plastics is 70 to 80 filaments. The thickness of the surface layer is 0.45 mm to 0.75 mm. The thickness of the sealing layer is 1.0 mm to 1.5 mm, and Glass fiber reinforced plastics comprise glass fibers and a matrix resin bonded to the glass fibers, and based on the total weight of the matrix resin, the matrix resin comprises 50% to 60% by weight of bisphenol A epoxy resin, 30% to 40% by weight of polyamide, and 5% to 10% by weight of urea.

2. The seal for reinforcing body panels according to claim 1, wherein, The sealing layer comprises 30% to 50% epoxy resin, 3% to 10% curing agent, 1% to 5% tackifier, 13% to 35% filler, 1% to 10% hygroscopic agent, 3% to 5% flow inhibitor and 1% to 2% stabilizer.

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