Silicone sealants cure by condensation reactions with moisture in the air to remove volatile small molecules. Depending on the small molecules removed by chemical reactions, glass adhesives can be divided into three categories: acid adhesives, neutral ketoxime type adhesives and neutral alcohol type adhesives. So different glass adhesives have different restrictions on the applicable substrates.
Acetic Silicone Sealants
Acetic silicone sealants emits acetic acid when curing, which has obvious corrosion on concrete, porous stone and many metal materials, so it can only be used for sealing ordinary glass, toughened glass and ordinary aluminum. The range of application is also different depending on the grade. For example, TB252/TB352 can only be used for sealing ordinary aluminum doors and windows, while to bond large plate glass and fish tanks can only use TB053/TB054 for bonding and sealing, and the size of the applicable fish tank is 1.5m*0.6m*1m.
Neutral Ketoxime Silicone Sealant
The ketoxime silicone sealant emits ketoxime when curing, which is safe for most substrates, but it is also corrosive for a few substrates, especially copper, so it cannot use for copper substrates. When used for coated glass and mirror glass, due to the unknown nature of the coating, compatibility tests must carry out first, to confirm the qualified before use. Also due to the different properties, the scope of its application is different. For example, silicone sealant TB995 miscellaneous colors are suitable for joint widths of 3cm. Silicone sealant TB751 miscellaneous colors are suitable for joint widths of 1.5cm. Silicone sealant TB798 miscellaneous colors are suitable for joint widths of 0.8cm, and the depth of the joint is preferably between 6mm-12mm. For engineering needs, the joint design and selection of suitable sealant must be carry out according to the provisions of JGJ 102-2003 “Technical Specification for Glass Curtain Wall Engineering”. For project requirements, the joint design and selection of the appropriate sealant must be carry out according to JGJ 102-2003 Technical Specification for Glass Curtain Wall Engineering.
Neutral Alcohol-based Silicone Sealant
Alcohol-based silicone sealants emit alcohol when curing, are non-corrosive and have no irritating odor, are non-corrosive to most substrates and have no basic substrate limitations. The biggest advantage of alcohol silicone sealant over ketoxime silicone sealant is that they can bond copper substrates and silicone sealant TB541 can bond mirrors. Currently, the main alcohol-based adhesives are silicone sealant TB541 for mirror structures, silicone sealant TB798, and silicone sealant TB751 neutral miscellaneous alcohol-based silicone sealant.
In addition to the above restrictions, compatibility or bonding tests should be carried out first for unknown substrates to ensure that they are qualified before construction can be carried out to avoid abnormalities of poor bonding or cracking of the product.K