What are the performance standards for rubber sealing tapes in the automotive industry?

　　The automotive industry has stringent performance standards for rubber sealing tapes, requiring a balance of core attributes such as sealing performance, durability, and environmental resistance, while also meeting the testing specifications of vehicle manufacturers and industry-wide standards (such as GB, ISO, and SAE). The following are the key performance standards and their corresponding test requirements:

　　I. Basic Physical Performance Standards

　　1. Hardness and Elasticity Indices

　　Hardness: Tested according to GB/T 531.1 (Shore hardness), automotive sealing tapes typically require a Shore A hardness of 40–70 degrees (for EPDM materials) or 30–50 degrees (for foamed rubber). The hardness must be matched to the compression requirements of the sealing area—for example, door frame seals need to be soft and resilient, while sheet-metal joints require a certain level of hardness for structural support.

　　Tensile Strength and Elongation at Break: Tested according to GB/T 528, the EPDM tape has a tensile strength ≥5 MPa and an elongation at break ≥300%; the butyl rubber tape has a tensile strength ≥3 MPa and an elongation at break ≥400%, ensuring that the tapes will not tear during assembly or deformation.

　　Compression Set: Tested according to GB/T 7759 (compression ratio of 25% under conditions of 70℃ × 22 hours). The deformation rate shall be ≤20% for EPDM or ≤30% for butyl rubber. The key assessment criterion is the ability of the adhesive tape to return to its original shape after prolonged compression (for example, if a car door seal deforms excessively, it may result in poor sealing and leakage of air or water).

　　2. Bonding Performance Standards

　　Bonding Strength: Tested according to GB/T 2792 (Peel Adhesion) or GB/T 11211 (Tensile Bond Strength), the peel adhesion to substrates such as automotive sheet metal, glass, and plastics shall be ≥1.0 N/mm (for butyl double-sided adhesive tapes); the bonding strength shall be ≥1.0 MPa (for structural sealing tapes). This ensures that the tapes remain firmly adhered and do not lift or curl at the edges.

　　Adhesive tack: Tested according to GB/T 4851, under a 1 kg load at 23℃, the tape displacement shall be ≤2 mm/24 h (static); under high temperature (70℃), the displacement shall be ≤5 mm/24 h (dynamic), thereby preventing the tape from loosening due to vehicle vibration during driving.

　　II. Environmental Resistance Performance Standards

　　1. Temperature Resistance Standard

　　High- and low-temperature cycling test: According to GB/T 2423.22 (Temperature Change), the tape undergoes a cycle of -40℃ × 2 hours → room temperature × 30 minutes → 120℃ × 2 hours (≥100 cycles). After the test, the tape shows no cracking and no loss of adhesion; its tensile strength retention rate is ≥80%.

　　Long-term high/low temperature resistance:

　　Normal-temperature areas (such as car doors): Temperature resistance: -40℃ to 80℃; no significant performance degradation after testing.

　　High-temperature areas in the engine compartment (such as around the turbine): The silicone rubber tape must withstand 150℃ for 1000 hours or 200℃ for 24 hours without softening or cracking.

　　2. Weathering (Aging) Standards

　　Xenon lamp aging test: Tested according to GB/T 16422.2 (1000 h, blackboard temperature 65℃, relative humidity 50%). Adhesive tape after aging:

　　Color difference ΔE ≤ 4 (no noticeable discoloration in appearance);

　　Tensile strength retention rate ≥ 70%; elongation at break retention rate ≥ 70%.

　　Bond strength retention rate ≥ 80% (a core requirement for outdoor exposed areas such as sunroofs and exterior body seams).

　　Ozone Aging Test: Tested according to GB/T 7762 (40℃, ozone concentration 50 ppm, 20% elongation, 100 hours). The adhesive tape shows no cracking (EPDM material requires particular attention to ensure it does not crack due to ozone aging when exposed outdoors).

　　3. Medium Resistance Standard

　　Oil, Coolant, and Fuel Resistance: Tested according to GB/T 1690, after immersion in engine oil (100℃ × 72h), coolant (80℃ × 168h), or gasoline (23℃ × 48h):

　　Volume change rate ≤ ±10%; weight change rate ≤ ±8%.

　　Tensile strength retention ≥70%, with no swelling, no hardening, and no bonding failure (key indicators for underbody and engine compartment tapes).

　　Water-resistant / Salt-spray resistant:

　　Water Resistance: Tested according to GB/T 1690, after immersion in distilled water (70℃ × 168 h), the volume change rate is ≤ ±5%, and the bond strength shows no reduction.

　　Salt Spray Test: Tested according to GB/T 10125 (5% NaCl solution, 35℃, 1000 hours). No rust or delamination at the bond with the metal substrate (required for vehicles used in the underbody area or coastal regions).

　　III. Sealing Performance Standards

　　1. Waterproofness test

　　Hydrostatic Pressure Test: Conducted according to IPX7 standard (water depth of 1 m for 30 minutes) or a full-vehicle rain test (water pressure of 0.05 MPa for 30 minutes), with no water seepage or leakage at sealed areas (such as the front and rear windshields and headlight seals).

　　Air-tightness test: Tested according to GB/T 12480, the vehicle’s overall air tightness shall be ≤20 m³/h (@500 Pa pressure difference). There shall be no air leakage at the tape joints (which could affect in-vehicle sound insulation and air conditioning energy efficiency).

　　2. Soundproofing and Vibration Reduction Performance

　　Sound insulation performance: According to GB/T 19889.3 testing, the tape must reduce in-vehicle noise by ≥3 dB(A) (e.g., for door and sunroof seals), and achieve a high-frequency noise reduction (2000–4000 Hz) of ≥5 dB(A).

　　Shock-absorbing performance: Tested according to GB/T 18941, the dynamic compression modulus is ≤10 MPa (for foam tape), ensuring cushioning and noise reduction when doors are closed and reducing vibration transmission during driving.

　　IV. Industry- and OEM-Specific Standards

　　1. General industry standards

　　GB (Chinese National Standard): GB/T 12363 (General Requirements for Rubber Sealing Products), GB/T 214 (Rubber Seals);

　　ISO (International Standards): ISO 815 (Compression Set), ISO 188 (Thermal Air Aging), ISO 1431 (Ozone Aging);

　　SAE (Society of Automotive Engineers): SAE J2260 (Fluid Resistance Test for Automotive Rubber Components), SAE J1970 (Weathering Resistance of Automotive Seals).

　　2. Vehicle manufacturer’s enterprise standards

　　Leading automakers (such as Volkswagen VW 50115, Toyota TSM 0500G, and General Motors GM 6042M) will set even stricter requirements based on industry standards:

　　VW 50115: The sealing tape shall have a bond failure area of ≤5% after being subjected to a temperature cycle ranging from -40℃ to 100℃.

　　Toyota TSM 0500G: The aging test time for xenon lamps has been extended to 2000 hours, with a strength retention rate of ≥75%.

　　New energy vehicle companies (such as Tesla): Battery pack sealing tapes must meet IP67/IP68 waterproof ratings, UL94 V-0 flame-retardant grade, and withstand high and low temperatures from -40℃ to 85℃ (1000 hours).

　　V. Environmental and Safety Standards

　　VOCs (Volatile Organic Compounds): Tested according to GB/T 27630 (Indoor Air Quality) or VDA 277, total VOCs ≤ 1000 μg/m³, formaldehyde ≤ 50 μg/m³, benzene series compounds ≤ 50 μg/m³, to prevent unpleasant odors and the release of harmful substances inside the vehicle.

　　ELV (End-of-Life Vehicles Directive): Complies with the EU ELV Directive and China’s GB/T 30512. Prohibits the use of heavy metals such as lead, cadmium, and mercury; tape materials must be recyclable (e.g., TPE/TPV materials).