Rubber sealing strips, as functional accessories made of rubber as their core material, play a key role in preventing the intrusion of dust, moisture, and impurities in automobiles, machinery, doors and windows, and other applications. Their performance is determined by the material's properties, leading to a wide range of applications.

Mainstream Material Performance Comparison

Sealing strips made of different rubber materials vary significantly in terms of temperature resistance, weather resistance, and mechanical strength, as follows:

EPDM sealing strips: Offer excellent overall performance, including outstanding ozone resistance, excellent weather resistance, good resistance to high temperatures (+150°C) and low temperatures (-60°C), resistance to a wide range of polar solutes, and a low relative density. However, their disadvantages include significant swelling in common mineral oils and lubricants, and they are generally dark-colored. They are suitable for most common applications, such as automobiles, machinery, doors and windows.

Silicone rubber sealing strips: Offer unparalleled insulation properties, meet food hygiene standards, and have an extremely wide operating temperature range (-100°C to +300°C). They also offer adequate breathability and can be manufactured in a variety of colors. However, it has the lowest mechanical strength among rubber materials and is not oil-resistant. It is suitable for use in areas with high temperatures, cold temperatures, and strong UV radiation, as well as in mid- to high-rise buildings.

Thermoplastic elastomer sealant strips: They offer good elasticity, excellent abrasion resistance, good oil resistance, a wide adjustable hardness range (65-80 Shore A), superior mechanical properties (tensile strength and elongation at break), and excellent cold and chemical corrosion resistance. While recyclable, the raw material is relatively expensive. They are suitable for use in areas subject to strong vibration, such as earthquake-prone areas, near railways, or in factories with high-powered cranes, as well as in areas with strong UV radiation.

Thermoplastic vulcanizate sealant strips: They possess the flexibility and elasticity of rubber and can be produced using plastic processing methods without the need for vulcanization. Waste can be recycled. They offer good heat and cold resistance (operating temperature range -40-150°C), a low relative density, and oil and solvent resistance comparable to that of chloroprene rubber. However, their compression set and abrasion resistance are less favorable.

Classification by Location and Purpose

Depending on their installation location and function on various devices or structures, rubber sealing strips can be categorized as follows:

Window glass sealing strips: Used to seal window glass, preventing moisture and dust from entering the vehicle interior.

Door sealing strips: Used to seal vehicle doors, ensuring a tight seal when closed.

Decorative strips and moldings: Mainly used for decoration and auxiliary sealing.

Other sealing strips: These include trunk lid sealing strips, engine hood sealing strips, radiator sealing strips, and emergency door sealing strips, used for sealing various components.

Multi-Dimensional Classification System

In addition to being categorized by material, location, and purpose, rubber sealing strips can also be categorized as follows:

Classification by Hardness: They can be divided into solid sealing strips and foam sealing strips. Solid sealing strips generally have a hardness between 65 and 90 degrees and are suitable for applications requiring a higher degree of hardness. Foam sealing strips have a hardness between 15 and 35 degrees and are soft and resilient, making them suitable for applications requiring a good seal and comfortable fit. Classification by cross-sectional shape: Cross-sectional shape design is crucial to performance. Common cross-sectional shapes include the sealing lip, bottom, and outer lap. Factors such as glass lift resistance, sealing, and aesthetics must be considered during design.

Classification by curing method: There are two types of curing methods: discontinuous curing and continuous curing. Discontinuous curing involves cutting the extruded rubber strip into specific lengths and then curing it in an autoclave. This method is suitable for certain products. Continuous curing methods include microwave continuous curing, salt bath continuous curing, and hot air continuous curing. Microwave continuous curing is widely used due to its high efficiency, energy saving, and high product quality. Salt bath continuous curing is gradually being phased out due to environmental pollution concerns. Hot air curing uses high-temperature, high-velocity hot air to achieve curing, offering greater safety.

Industry Development Trends

Material Innovation: With increasing environmental protection requirements, recyclable and low-VOC (volatile organic compound) materials are becoming a trend. For example, thermoplastic elastomer (TPE) sealing strips are increasingly widely used due to their recyclability. Furthermore, silicone rubber sealants meet environmental protection requirements. Although not yet widely adopted, they hold great potential in areas such as energy-saving doors and windows for low-carbon buildings.

Performance Optimization: To meet the specific needs of different scenarios, the functionality of sealing strips is increasingly becoming more complex. For example, some sealing strips integrate multiple properties, including sound insulation, heat insulation, and waterproofing, in addition to their original sealing function, to meet the increasing demands for energy conservation and comfort in the automotive and construction sectors.

Process Improvement: In terms of production technology, microwave continuous vulcanization, a type of continuous vulcanization method, continues to dominate due to its high efficiency, energy efficiency, and high product quality. Traditional salt bath continuous vulcanization is being phased out due to environmental concerns, while hot air vulcanization is also gaining some application due to its higher safety.

Customization: Market demand for customized sealing strips is growing to meet the individual needs of different industries and equipment. Companies can develop and produce specialized sealing strips based on customer-specified cross-sectional shapes and performance requirements to improve sealing effectiveness and product compatibility.