Double skinned epdm sheet, seal and method of manufacturing a seal

Abstract

The application discloses a double-skin EPDM sheet, a sealing element and a preparation method of the sealing element, which comprises an EPDM three-element ethylene propylene rubber open-cell foamed sheet layer and an EPDM film layer, and the surface of the EPDM three-element ethylene propylene rubber open-cell foamed sheet layer is exposed to a plurality of pores, the opening surface of the pores is connected with the EPDM film layer in a blocking mode, and the pores become closed-cell air elastic capsules. Through the above mode, the excellent characteristics of the EPDM three-element ethylene propylene rubber open-cell foamed sheet are reserved, the reliability of compression sealing of the sheet is ensured through the closed-cell air elastic capsule structure, the defects that the EPDM three-element ethylene propylene rubber open-cell foamed sheet is easy to be compressed and deformed to leak rainwater are eliminated, and the compression buffering performance is improved; the cost is 60% of that of the EPDM three-element ethylene propylene rubber closed-cell foamed sealing element, the price competitiveness is strong, and the technical performance indexes meet the requirements of automobile manufacturers.

Description

Technical Field

[0001] This invention relates to the field of composite materials, and in particular to a double-sided skinned EPDM sheet, a sealant, and a method for preparing the sealant. Background Technology

[0002] Open-cell foam materials (also known as interconnected-cell foams): The cells in open-cell foam materials are interconnected, or completely interconnected, allowing gas or liquid to pass through in one or three dimensions. The cell diameter varies from 0.5 to 3 mm. Due to its unique structure, open-cell foam materials possess the following characteristics:

[0003] 1. Superior compressibility: It can be compressed under low stress, has low rebound force, and is easy to recover.

[0004] 2. Thermal insulation: Although it has an open-cell structure, the pores are complex, and it has the same thermal insulation effect as closed-cell materials.

[0005] 3. Water-stopping and water-retaining properties: Water will not leak after compression, and internal moisture is not easily lost.

[0006] 4. Sound absorption: Due to its high porosity and complex internal pore structure, sound wave energy is attenuated, thus exhibiting excellent sound absorption performance.

[0007] Closed-cell foam materials: These materials have an independent cell structure, with each cell separated by a wall membrane and not interconnected. Closed-cell foam materials possess excellent impact resistance, resilience, flexibility, sound insulation, heat insulation, water resistance, and vapor resistance.

[0008] Ethylene-Propylene-Diene Monomer (EPDM) is a terpolymer of ethylene, propylene, and a non-conjugated diene. The diene has a unique structure; only one of its two bonds can copolymerize. The unsaturated double bond primarily serves as a crosslinking site. The other unsaturated bond does not become part of the polymer backbone but rather a side chain. The main polymer chain of EPDM is completely saturated. This characteristic makes EPDM resistant to heat, light, oxygen, and especially ozone. EPDM is inherently nonpolar, resistant to polar solutions and chemicals, has low water absorption, and possesses excellent insulating properties.

[0009] Today's consumers demand high-quality cars at low prices, requiring excellent value for money. OEMs are also pushing down the prices of auto parts, especially in automotive sealing materials. For example, using EPDM (ethylene propylene diene monomer) closed-cell foam sheets to develop headlight gaskets results in a higher cost for the gaskets than the OEMs would pay. This means that auto parts manufacturers will suffer losses and become unprofitable, making it difficult for downstream companies to survive. However, the OEMs' technical performance requirements have not decreased.

[0010] However, sealing components made from EPDM (ethylene propylene diene monomer) rubber open-cell foam sheets have many defects and are frequently the subject of customer complaints. The main reason for these complaints is that open-cell foam seals are prone to water leakage, especially during rain or car washes. When rainwater accumulates on the headlight housing, tiny amounts of moisture seep in through the defective seals, causing condensation and fogging inside the headlight. This affects the headlight's low beam performance, making it difficult to see the road ahead and creating a safety hazard. Summary of the Invention

[0011] The main technical problem solved by this invention is to provide a double-sided skinned EPDM sheet, a sealant, and a method for preparing the sealant, which can retain the original excellent properties of EPDM terephthalic acid rubber open-cell foamed sheet, overcome the defects of its surface open-cell structure, improve the pressure resistance and cushioning performance, prevent rainwater leakage and meet the requirements of engineering applications, and significantly reduce costs.

[0012] To solve the above-mentioned technical problems, the present invention adopts a technical solution as follows: providing a double-sided skinned EPDM sheet, comprising: an EPDM ethylene propylene diene monomer (EPDM) open-cell foam sheet layer and an EPDM film layer. The surface of the EPDM EPDM open-cell foam sheet layer has a plurality of exposed pores. The open surfaces of the pores are sealed and connected to the EPDM film layer, making the pores into closed-cell air elastic capsules, so that its compression resistance and resilience are comparable to those of the EPDM EPDM closed-cell foam sheet.

[0013] In a preferred embodiment of the present invention, the pores on both the upper and lower surfaces of the EPDM EPDM open-cell foam sheet are sealed and connected by an EPDM film layer. This film is fused to the sheet surface, sealing and firmly bonding all exposed pores on the open-cell foam sheet surface, preventing rainwater from penetrating into the interior of the open-cell foam material, thereby meeting the requirements of automotive headlight sealing components.

[0014] In a preferred embodiment of the present invention, the surface of the EPDM film layer used for sealing is provided with a vulcanizing agent sealing layer, and the vulcanizing agent sealing layer is firmly fused to the EPDM EPDM open-cell foam sheet layer.

[0015] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a sealing element made of EPDM sheet with double-sided skin, including any of the above-mentioned EPDM sheet with double-sided skin.

[0016] In a preferred embodiment of the present invention, an adhesive layer is attached to the surface of the double-sided skinned EPDM sheet, and the adhesive layer is connected to the surface of the EPDM film layer for bonding the sealing components. A release paper layer for transportation and storage is provided on the surface of the adhesive layer.

[0017] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is: to provide a method for preparing a sealing element, comprising the following steps:

[0018] 1) Prepare EPDM (ethylene propylene diene monomer) rubber open-cell foam sheets, EPDM film, and vulcanizing agent;

[0019] 2) Apply a vulcanizing agent to the surface of the EPDM membrane;

[0020] 3) Hot-press vulcanize the surface of the EPDM film with vulcanizing agent with EPDM EPDM rubber open-cell foam sheet to form a composite sheet with at least 3 layers.

[0021] 4) Apply adhesive backing to the composite sheet and then die-cut it into various shapes of seals.

[0022] In a preferred embodiment of the present invention, the vulcanization temperature of the hot pressing vulcanization is 160-180℃, the length of the vulcanization heat preservation section is 4-7 meters, the vulcanization time is 4-8 minutes, and the hot pressing feed speed is 1-3 m / min.

[0023] In a preferred embodiment of the present invention, the vulcanizing agent is a sulfur vulcanizing agent.

[0024] The beneficial effects of this invention are as follows: On the one hand, this invention retains the excellent weather resistance, ozone resistance, heat resistance, stability, and good thermal insulation, heat insulation, anti-slip, cushioning, shock absorption, sound absorption, sound insulation, and sealing properties of EPDM open-cell foam sheets. On the other hand, the closed-cell air elastic capsule structure ensures the reliability of the sheet's compression sealing, eliminates the defect of EPDM open-cell foam sheets being easily compressed and deformed, leading to rainwater leakage, and improves the compression and cushioning performance. The cost of this invention is 60% of that of EPDM closed-cell foam sealants, making it highly competitive in price and meeting the requirements of automotive OEMs in terms of both technical performance indicators. Attached Figure Description

[0025] 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 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, wherein:

[0026] Figure 1 This is a schematic diagram of a preferred embodiment of the sealing element made from EPDM sheet with double-sided skinning according to the present invention. Detailed Implementation

[0027] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this invention, it should be noted that the terms "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] The embodiments of the present invention include:

[0034] A double-sided skinned EPDM sheet includes: an EPDM EPDM open-cell foamed sheet layer 1 and an EPDM film layer 2. The surface of the EPDM EPDM open-cell foamed sheet layer 1 has a plurality of exposed pores 11. The open surfaces of the pores are sealed and connected to the EPDM film layer 2, so that the pores become closed-cell air elastic capsules.

[0035] In a preferred embodiment of the present invention, the pores on both the upper and lower surfaces of the EPDM ethylene propylene diene monomer (EPDM) rubber open-cell foamed sheet layer 1 are sealed and connected by an EPDM film layer 2, such as... Figure 1 As shown.

[0036] The EPDM film layer 2 has a vulcanizing agent sealing layer 21 on its sealing surface, which is firmly fused to the EPDM EPDM open-cell foam sheet layer 1. This prevents rainwater from penetrating into the open-cell foam material, thus ensuring the effective optical performance of the vehicle headlight and meeting the requirements for automotive headlight sealing components.

[0037] The present invention also relates to a sealing element comprising the aforementioned double-skinned EPDM sheet. An adhesive layer 3 is attached to the surface of the double-skinned EPDM sheet, and the adhesive layer 3 is connected to the surface of the EPDM film layer 2 for bonding and assembling the sealing element. A release liner 4 for transport and storage is provided on the surface of the adhesive layer.

[0038] The seal of this invention exhibits excellent aging resistance, weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical properties, oil filling properties, and room temperature flowability. It can be used continuously at 120°C and for short-term or intermittent use at 150-200°C. Adding suitable antioxidants can increase its operating temperature. Peroxide-crosslinked EPDM rubber can be used under harsh conditions. EPDM rubber can withstand ozone concentration of 50 pphm and 30% stretching without cracking for over 150 hours.

[0039] The sealing element of this invention has good corrosion resistance, lacks polarity, and has low unsaturation, thus exhibiting good resistance to various polar chemicals such as alcohols, acids, alkalis, oxidants, refrigerants, detergents, animal and vegetable oils, ketones, and esters.

[0040] The sealing element of this invention exhibits excellent water vapor resistance, surpassing even its heat resistance. After nearly 100 hours in superheated steam at 230°C, its appearance remains unchanged. In contrast, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, nitrile rubber, and natural rubber show significant deterioration in appearance within a shorter time under the same conditions.

[0041] The seal of this invention has good resistance to hot water, and the EPDM rubber also has good resistance to hot water. After being soaked in hot water at 125°C for 15 months, the mechanical properties change very little and the volume expansion rate is only 0.3%.

[0042] The sealing element of the present invention has good insulation performance, excellent electrical insulation performance and corona resistance, and its electrical performance is better than or close to that of styrene-butadiene rubber, chlorosulfonated polyethylene, polyethylene and cross-linked polyethylene.

[0043] The sealing element of the present invention has good flexibility. Because there are no polar substituents in the molecular structure of EPDM ethylene propylene diene monomer (EPDM) open-cell foam sheet, the molecular cohesive energy is low, and the molecular chain can maintain flexibility over a wide range, and can still maintain it at low temperatures.

[0044] This invention also relates to a method for preparing a seal, comprising the following steps:

[0045] 1) Prepare EPDM ethylene propylene diene monomer (EPDM) rubber open-cell foam sheets, EPDM film, and vulcanizing agent, wherein the vulcanizing agent is preferably a sulfur vulcanizing agent;

[0046] 2) Apply a vulcanizing agent to the surface of the EPDM membrane;

[0047] 3) Hot-press vulcanize the surface of the EPDM film with vulcanizing agent with EPDM EPDM rubber open-cell foam sheet to form a composite sheet with at least 3 layers.

[0048] 4) Adhesive backing is laminated onto composite sheets, and then die-cut into various shapes of seals, mainly used in automotive headlight seals.

[0049] The hot-press vulcanization process is characterized by a vulcanization temperature of 160-180℃, a vulcanization insulation section length of 4-7 meters (preferably 5 meters), a vulcanization time of 4-8 minutes (preferably 5 minutes), and a hot-press feeding speed of 1-3 m / min (preferably 1 m / min).

[0050] In summary, this invention retains the excellent weather resistance, ozone resistance, heat resistance, stability, and good thermal insulation, anti-slip, cushioning, shock absorption, sound absorption, sound insulation, and sealing properties of EPDM open-cell foam sheets. Furthermore, the closed-cell air elastic capsule structure ensures the reliability of the sheet's compression sealing, eliminating the defects of EPDM open-cell foam sheets that are prone to compression deformation and rainwater leakage, thus improving compression resistance and cushioning performance. The cost of this invention is 60% of that of EPDM closed-cell foam sealants, making it highly competitive in price and meeting the technical performance requirements of automotive OEMs.

[0051] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A seal prepared from a double skinned EPDM sheet material characterised in that, The application relates to a double-skin EPDM sheet, which comprises an EPDM three-element ethylene propylene rubber open-cell foam sheet layer and an EPDM film layer, the surface of the EPDM three-element ethylene propylene rubber open-cell foam sheet layer is exposed with a plurality of pores, the opening surface of the pores is connected with the EPDM film layer in a sealing mode, so that the pores become closed-cell air elastic capsules; the pores on the upper and lower surfaces of the EPDM three-element ethylene propylene rubber open-cell foam sheet layer are connected with the EPDM film layer in a sealing mode; the surface of the EPDM film layer used for sealing is provided with a vulcanizing agent sealing layer, and the vulcanizing agent sealing layer is firmly fused with the EPDM three-element ethylene propylene rubber open-cell foam sheet layer. The application further relates to a sealing element prepared from the double-skin EPDM sheet and a preparation method of the sealing element, which comprises the following steps: 1) preparing an EPDM three-element ethylene propylene rubber open-cell foam sheet, an EPDM film and a vulcanizing agent; 2) coating the surface of the EPDM film with the vulcanizing agent; 3) hot-pressing and vulcanizing the surface of the EPDM film with the vulcanizing agent and the EPDM three-element ethylene propylene rubber open-cell foam sheet to form a composite sheet with at least three layers; the vulcanization temperature of the hot-pressing and vulcanization is 160-180 DEG C, the vulcanization holding section is 4-7 meters long, the vulcanization time is 4-8 minutes, and the hot-pressing feeding speed is 1-3 m / min; 4) compounding a back adhesive on the composite sheet, and then die-cutting and forming the back adhesive into various shapes of sealing elements. The surface of the double-skin EPDM sheet is connected with an adhesive layer, the adhesive layer is connected with the surface of the EPDM film layer, is used for assembling and bonding the sealing element, and the surface of the adhesive layer is provided with a release paper layer for transportation and storage.

2. The seal of claim 1, wherein The vulcanizing agent is a sulfur vulcanizing agent.

3. The seal of claim 1, wherein ​

Images