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

A manufacturer of complete sets of insulated glass equipment tells you: The sealing strips of doors and windows are one of the most important factors affecting their quality. They need to play a vital role in waterproofing, sealing, and energy conservation. They also possess functions such as sound insulation, dustproofing, frost protection, and heat insulation, while having high tensile strength, good elasticity, and good temperature resistance and aging resistance. Currently, the sealing strip market mainly uses modified PVC, vulcanized EPDM rubber sealing strips, and thermoplastic EPDM rubber (EPDM/PP) strips. However, in this mixed market environment, how can you 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 terminal energy consumption. Energy loss through gaps around 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 and major cities in China, such as Beijing, have phased out or restricted the use of PVC rubber strips.

2. Vulcanized EPDM Sealing Strips

Vulcanized EPDM rubber sealing strips offer stronger sealing elasticity and durability than PVC strips. However, they require microwave vulcanization for shaping, resulting in high processing energy consumption—typically more than 20 times that of PVC processing. These products are not reusable, are not environmentally friendly, and are not products promoted by the government.

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 and development. They are mainly 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. In addition, they can be recycled after several years, meeting the requirements of green building materials. In recent years, they have begun to be used for building door and window sealing strips.

Classification and Quality Identification Methods of Door and Window Sealing Strips!

1. Burning Method (Distinguishes between thermoplastic and rubber-based strips)A. Rubber-based strips burn to ash and cannot be drawn into threads. Silicone rubber has white ash, and if the extinguished area remains white after rubbing on white paper, it's likely silicone rubber. EPDM or neoprene rubber has black ash, and if the extinguished area remains black after rubbing on white paper, it's likely EPDM or neoprene rubber. Natural rubber has black ash and the extinguished area feels sticky to the touch.

B. Thermoplastic elastic 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 melt-stringing phenomenon, floats on the water surface or remains suspended.

D. SEBS thermoplastic elastomer sealing strip: Matte surface, exhibits melt-stringing phenomenon, slowly sinks in water.

2. Tensile Strength Test

Relatively speaking, sealing strip materials should possess a certain tensile strength. The standard requirement is: strength ≥ 5 MPa. For the same material, a higher rubber content generally results in better tensile strength, longer service life, and better sealing effect.

3. Odor Test

Smell for any unusual odor. 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 at a high temperature for a period of time (on a rooftop or in a sunny location).

Observe whether the contact surface between the profile and the sealing strip shows any dirt or discoloration, whether the dust on the sealing strip surface is yellowed (oil easily attracts dust), whether there is oil seepage, and whether it is sticky or dirty to the touch.

5. Some cheaper sealing strips contain a lot of filler, so the surface is not very shiny. Those cheap ones with a dull appearance are not recommended.