The Urethane Systems business unit of specialty chemicals company LANXESS presented innovative material developments at this year’s Polyurethane Manufacturers Association (PMA) annual meeting. They presented two new prepolymers of the Adiprene range that are produced using low free (LF) technology so they contain very low diisocyanate content. The PMA took place August 7-9 in Salt Lake City, Utah, USA.
Meeting highest requirements
One of the most challenging applications for polyurethane casting systems is high-temperature applications. As polyurethane chemistries have advanced over the years, casting systems are being used more frequently in this high-performance segment. Ian Laskowitz, Applications Development Manager for Urethane Systems at LANXESS, highlighted at the PMA Meeting the novel Adiprene LF TR400 high-temperature prepolymer, which is based on polycarbonate.
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In the pilot plant in Latina, Italy, LANXESS is researching and developing prepolymers |
This low free TDI prepolymer is cured with MCDEA (4,4'-methylenebis(3-chloro-2,6-diethyl-aniline) It is much easier to process than comparable prepolymer systems for high-temperature applications. For example, it offers a manageable processing/pour life. The resulting cast elastomers demonstrate have improved high-performance properties that comparable established polyurethane high-temperature system and have excellent high-temperature property retention. Thus, the tear strength is hardly reduced at elevated temperatures. A further strength is high resistance to heat aging at 150 ⁰C.
Laskowitz’s presentation expanded on the use of physical property testing at high temperature, comparing this new prepolymer to standard cast urethane materials, as well as high temperature physical property retention after heat aging at high application temperatures. The processing needs of the materials were also discussed.
Easy processing and enhanced performance
LANXESS developed a unique 1K blocked prepolymer, Adiprene K LFM E820, based on caprolactam (CAP) blocked prepolymer and diamine curatives. This was the focus of the presentation given by Senior Chemist George Brereton at the PMA annual meeting.
Less viscous blocked prepolymer systems, which are based on LF technology, allow for chemistries with non-traditional raw materials, including more viscous polycarbonate polyols and unique amine types. These stable 1K systems provide processors with numerous advantages, including increased control of the curing process and increased product consistency from batch to batch. Without restriction on pot life, these systems allow for the processing of large parts, complex contour designs, and roto-molding of hollow parts. These systems can offer enhanced thermos-mechanical performance, processing ease, and enhanced industrial hygiene.
The variety of possible applications of blocked LF prepolymers ranges from small thicknesses of 1-2 mm to really large parts up to several tons. For example, these systems are used as abrasive pad binders or coatings of industrial rollers, as well as in the impregnation of industrial belts. Another advantage for the processor is the elimination of the need for a mixing and metering system, which pays off in terms of component costs. Potential applications include dynamic bend stiffeners for thick cables such as submarine cables, industrial rolls, components for wind turbine rotor blades or large composite structures.
The LANXESS Urethane Systems business unit is one of the world’s leading suppliers of polyurethane systems for elastomers, coatings, adhesives and sealants with special focus on solvent-free and monomer-free systems, and provides its customers decades of urethane chemistry know-how, comprehensive application expertise, and deep manufacturing experience.
