Desmodur®, Desmocap® and Desmoseal® - market leaders in prepolymers for adhesives applications
Prepolymers are a group of materials representing a reactive intermediate between monomeric isocyanates and polyurethane polymers. They are the reaction product of a polyol component with a surplus of a polyisocyanate component. The properties of these prepolymers and the finished adhesives or sealants can largely be modified by selecting a suitable polyol component (like polyester or polyester) and the polyisocyanate component (like aromatic or aliphatic), by the molar ratio of these two reaction partners and by the subsequent formulation (catalyst, filler, plasticizer,...).
The applications listed above represent the most common applications, however, other applications are possible, too. Please discuss your applications with our experts for a suitable solution.
Desmodur® E prepolymers contain free isocyanate groups. Therefore, they can be used like an NCO-component in formulations of solvent-based, solventfree and waterfree adhesives and sealants. By selecting a suitable prepolymer the processing conditions of the adhesive or sealant formulation can be adjusted and the mechanical properties of the finished product can precisely be fine-tuned. The crosslinking usually happens by moisture-curing through ambient humidity. Due to this virtual one-component curing mechanism, these products are mostly sold as "moisture-curing one-component products". Although it is quite possible to formulate them as two-component systems also, mostly with short-chain polyols or polyamines (formation of poly-urea). Prepolymers often offer advantages during formulation, like longer pot-life, increased initial bond strength, a reduced content of low-molecular substances or a more favorable balance of the components in the mixture.
Bayer MaterialScience also offers a series of Desmodur® E with a low residual monomer content (content of non-polymer-bound isocyanate components). These products make it possible to produce polyurethane adhesives and sealants that are not subject to particular labeling requirements.
Desmocap ® prepolymers are a special kind of prepolymer in that their isocyanate group is blocked. Therefore the reactivity of the product is decreased. A fast reaction can be slowed down that way or the reaction temperature can be increased. These products can be used for applications like flexible sealants or for rendering epoxy systems more flexible. Other applications are possible as well. Please contact our technical experts to discuss your project.
Elastic adhesives, flexibilisation of epoxy resins
Desmoseal® S products are silane terminated prepolymers that combine the advantages of polyurethane sealant systems with the advantages of silicone technology. Find out more
Desmoseal® M for polyurethane sealants
Bayer MaterialScience offers polyurethane prepolymers for moisture-curing one-component sealants under the trade name Desmoseal® M. These sealants can also be used to elastify harder systems like those based on Desmodur® E 21.