Technologien

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.

Product examples:

Isocyanate-
base
NCO-content in %
Viscosity
mPas at 23°C
Application (examples)
Desmodur® E 29
MDI
24.0
220
e.g. for primer for parquet/hardwood floor adhesion, corrosion protection
Desmodur® E 21
MDI
16.0
5400
e.g. for wood adhesives
Desmodur® E XP 2715
MDI
16.0
340 (100°C)
intermediate for the production of low-monomeric hotmelts

Some starting formulations:


BBB 6082

1K adhesive (Desmodur® E 23 / Desmophen® 5035 BT / Härter® DT)




BBB 6083

1K adhesive (Desmodur® E 23 / Desmophen® 5035 BT / Härter® DT

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.

Product examples:

Isocyanate-base
Residual monomer- content in %
NCO-
content in %
Viscosity
mPas at 23°C
Application examples
Desmodur VP LS 2397
MDI
< 0,3
~ 5,7
10000 (50°C)
Reactive polyurethane hotmelts, flexible packaging
Desmodur XP 2617
HDI
< 0,5
~ 12,5
4250
Lightfast adhesives


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.

Product examples:

NCO-content % blocked
Viscosity
mPas at 23°C
Molecular weight
g/mol
Application (examples)
Desmocap® 11
~ 2.4
100000
1750
Elastic adhesives, flexibilisation of epoxy resins
Desmocap® 12
~ 1.6
40000
2630
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.

Viscosity
mPas at 25°C
NCO-content in %
Plasticizer
Applications
Desmoseal® M 280
33000
2.1
20% Mesamoll
For moisture-curing one-component sealants and elastic adhesives

Some starting formulations:


BBB 6039

1K PUR adhesive, Shore A 45 (Desmoseal® M 280)




BBB 6040

1K PUR adhesive, Shore A 45 (Desmoseal® M 280)




BBB 6041

1K PUR sealant, Shore A 50 (Desmoseal® M 280)




BBB 6042

1K PUR sealant, Shore A 30 (Desmoseal® M 280 / Desmodur® E 15)


Look for more information on the product range for sealants in the section Applications - Sealants

Have a look at this additional information:

.PIC / Prepo Products
MS00063645


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