As we all know, the service life of buildings is generally at least 50 years, so the materials required to be used must also have a long service life. Silicone sealant has been widely used in the field of building waterproof sealing due to its excellent resistance to high and low temperature, excellent weathering resistance and good bonding performance. However, for a period of time after construction, the problem of discoloration of the silicone sealant emerged one after another, drawing abrupt "lines" to the building.

Incompatibility of different sealant materials

Acid sealant, neutral alcohol sealant, and neutral oxime sealant cannot be used together. They will affect each other and change color. Acid glass glue will cause the oxime glue to turn yellow and neutral oxime. It will also turn yellow when used together with neutral alcohol glass glue.

Contact with rubber and other materials

Silicone sealant will turn yellow when it is in direct contact with most rubbers (natural rubber, neoprene, three-free ethylene propylene rubber). These rubbers are widely used in curtain walls and doors and windows (rubber strips, rubber pads, etc.). This type of discoloration It is characterized by non-uniformity, discoloration of the parts directly with the rubber, and no discoloration of other parts.

The sealant is overstretched causing discoloration

This phenomenon can easily be mistaken for the loss of sealant color. There are three common causes of this type of discoloration.

1) Adhesive for ultra-displacement capacity, joint displacement is too large, and the sealant is over-stretched;

2) The local thickness of the sealant is too thin, causing the discoloration of the sealant to concentrate on the thin part;

Sealant is affected by environmental factors

This type of discoloration mostly occurs in neutral oxime sealants. The main cause of discoloration is that the air contains acidic substances. There are many sources of acidic substances in the air, such as the curing acid silicone sealant and the acrylic paint under construction. , Sulfur dioxide in the atmosphere, plastic garbage burned nearby, burning asphalt, etc., these acidic substances in the air can cause discoloration of the oxime sealant.