Brief Introduction Of Polyurethane Foam Joint Filler

1、 Main composition of polyurethane foam sealant
Foam adhesive is composed of polyurethane prepolymer, foam sealant, catalyst, cross-linking agent, etc., filled into high-pressure iron cans, and propane and other gases. It is a type of adhesive with foaming and bonding properties, mainly used for filling, sealing, and bonding edge joints of building doors and windows, expansion joints of components, and holes. It is a polyurethane elastic sealing foam material that relies on moisture curing.
There are two types of foam sealant: gun type and tube type. The gun type can only be used with a special polyurethane foam gun, and the tube type is equipped with disposable rubber hose.
2、 What is MDI (pure mdi, aggregated mdi), TDI, and the difference between the two?
The main raw material for prepolymers is isocyanate, which is MDI or TDI. MDI, also known as diphenylmethane diisocyanate, is a very important type of isocyanate and the main raw material for the production of polyurethane (PU). MDI can be divided into two categories as a whole: pure MDI (dibenzyl methane diisocyanate) and polymerized MDI (containing a mixture of a certain proportion of pure MDI and polyphenyl polymethylene polyisocyanate), among which pure MDI is mainly used in synthetic leather paste, spandex, and shoe sole stock, etc; Polymerized MDI is mainly used for polyurethane hard foam (such as insulation layers in refrigerators and freezers), polyurethane elastomers, and adhesives.
TDI is the abbreviation for toluene diisocyanate, a colorless, transparent or light yellow liquid that is an organic compound with strong irritating gases.
TDI is an important basic chemical raw material for the production of polyurethane materials, which is used for organic synthesis, production of foam plastics, coatings and chemical reagents.
What is the difference between TDI and MDI?
MDI and TDI are substitutes for each other and are both raw materials for producing polyurethane. However, due to differences in structure and performance, the segmented uses are greatly different: MDI is mainly used for polyurethane hard foam and semi hard foam, applied in insulation materials, automotive accessories, and the construction industry; TDI is mainly used in polyurethane soft foam, applied in industries such as furniture padding, sound-absorbing materials, and toys. Due to the highly toxic nature of TDI, its application is limited to some extent, and it is not as widespread as MDI.