Classification and quality identification methods of door and window sealing strips!

The sealing strips of doors and windows are a crucial factor affecting their quality. They must play a vital role in waterproofing, sealing, and energy conservation, while also providing sound insulation, dustproofing, frost protection, and heat insulation. Furthermore, they need high tensile strength, good elasticity, and excellent temperature and aging resistance. Currently, the sealing strip market mainly offers modified PVC, vulcanized EPDM rubber, and thermoplastic EPDM/PP rubber strips. However, in this mixed market environment, how can one distinguish superior quality? Today, the editor from the door and window market is here to offer some tips!

Classification and Characteristics of Door and Window Sealing StripsAccording to statistics, building energy consumption in my country accounts for 27.5% of the total social energy consumption. Energy loss through gaps in poorly sealed doors and windows typically accounts for about 37-40% of building energy consumption. Therefore, improving the sealing performance between the sash and glass, especially between the window frame and the window sash, is extremely important.

1. Modified PVC Rubber Strips

Modified PVC rubber strips are relatively inexpensive. However, due to varying quality, low-end products often use waste materials, substitute plasticizers, and high filler content, resulting in poor elasticity, easy hardening, a pungent odor, easy migration causing yellowing of the frame material, and a short service life. Because PVC products contain halogens and stabilizers contain heavy metals, they are environmentally unfriendly. Therefore, developed countries abroad, as well as Beijing and coastal cities in China, have phased out or restricted the use of PVC rubber strips.

2. Vulcanized EPDM Sealing Strips

Vulcanized EPDM rubber sealing strips offer superior sealing elasticity and durability compared to PVC strips. However, due to the need for microwave vulcanization, processing energy consumption is high, typically more than 20 times that of PVC processing. The product is not reusable, is not environmentally friendly, and is not a product promoted by the state.

3. Thermoplastic EPDM Sealing Strips

Thermoplastic EPDM rubber sealing strips are a new material developed in recent years based on imported technology and domestic independent research. Primarily used for automotive door and window sealing strips, their performance and service life are comparable to vulcanized EPDM rubber sealing strips. They do not contain halogens or heavy metals such as lead, and are recyclable after several years, meeting green building material requirements. In recent years, they have begun to be used in building door and window sealing strips.

How to choose sealing strips? Buyers need to develop a discerning eye.

1. Burning Method (can distinguish between thermoplastic and rubber-based strips)A. Rubber-based strips burn to ash and cannot be drawn into threads. A. Silicone rubber has white ash; if the extinguished area remains white after rubbing on white paper, it is ethylene propylene diene monomer (EPDM) or chloroprene rubber. Natural rubber has black ash and the extinguished area feels sticky to the touch.

B. Thermoplastic elastic rubber strips, after burning, can be drawn into threads at the extinguished area. EVA (ethylene-vinyl acetate copolymer) has a distinct acetic acid smell. PE (polyethylene) and PP (polypropylene) have a distinct candle-like smell, continue to burn, and are accompanied by melting and dripping. PVC (polyvinyl chloride) strips are self-extinguishing and produce black smoke and a pungent odor.

C. TPV thermoplastic vulcanized rubber: matte surface, exhibits melting and threading, floats on the surface or is suspended in water.

D. SEBS thermoplastic elastomer sealing strips: matte surface, exhibits melting and threading, and slowly sinks in water. 2. Tensile Strength TestRelatively speaking, sealing strip materials should possess a certain tensile strength. The standard requirement is: strength ≥ 5 MPa. For the same material, a higher adhesive content generally results in better tensile strength, longer service life, and better sealing performance.

3. Odor Test

Smell for any unusual odors. Normal PVC material has a slight alcoholic smell, but almost no other odor.

4. Wrap the sealing strip tightly around the profile and place it under high temperature for a period of time (on a rooftop or in a sunny location).

Check if the contact surface between the profile and the sealing strip shows any dirt or discoloration. Check if the surface of the sealing strip is yellowed (oil easily attracts dirt), leaks oil, or is it sticky or dirty to the touch.

5. Some cheaper sealing strips contain a lot of filler, resulting in a less glossy surface. Avoid very cheap, dull-looking sealing strips.