POLYURETHANES ARE VERSATILE
Polyurethanes are among the most versatile plastics materials. Polyurethanes can be used in a comprehensive range of applications.
Polyurethanes can be tailored from feather-light to heavyweight and from highly flexible to very rigid. Foams range in density from low to high. There are integral skin foams and solid polyurethanes, such as elastomers.
Polyurethane systems for a wide range of applications must fulfil various requirements depending on the end-product and processing performance.
RIGID POLYURETHANE FOAMS
For rigid foams, low thermal conductivity and good temperature resistance are usually important. It is also important that systems have excellent flow properties that enable the foam to fill narrow cavities.
Rigid foams are used in the manufacture of refrigerators and freezers and in the construction sector in insulation boards, panels and preinsulated pipes.
CONFERENCE PAPER
- BROENNUM, Chemical Research Centre, Shell Louvain-la-Neuve
CFC-Free Polyurethane Pipe Insulation Foams for Use in district Heating Systems
JOURNAL OFCELLULAR PLASTICS, Volume 28 – May 1992
This paper was presented at Polyurethanes World Congress 1991, Nice
PATENTS
POLYETHER-POLYOL, METHOD FOR PRODUCTION THEREOF, POLYETHER-POLYOL BLEND, AND RIGID POLYURETHANE FOAM
Inventor(s): BROENNUM THOMAS [BE]; SANGHA PARMINDER SINGH [NL]; STEINMETZ JOHANNES CORNELIS [BE] +
Applicant(s): SHELL INT RESEARCH [NL] +
Priority number(s): EP19950203399 19951207
Also published as: EP0778302 (A1) EP0778302 (B1) US5824714 (A) TW505672 (B) SK155796 (A3)
Bibliographic data: US6538043 (B1) ― 2003-03-25
Co-initiated polyether polyol and process for its preparation
Inventor(s): BRONNUM THOMAS [BE]; HASSELAAR MELIS [NL]; SANGHA PARMINDER SINGH [NL]; VAN TIGGELEN FRANCOISE [BE] +
Applicant(s): SHELL OIL CO [US] +
Application number: US20010786775 20010308
Priority number(s): EP19980203026 19980910 ; WO1999EP06658 19990908
Also published as: WO0015689 (A1) US2003125407 (A1) RU2222550 (C2) PL346538 (A1) ES2207279 (T3)
FLEXIBLE POLYURETHANE FOAMS
Flexible, low to medium-high density foams include hypersoft, high resilience, high load-bearing and viscoelastic types. Cell size can vary from very fine to coarse but foams always have at least a partially open-celled structure.
Major areas of application for flexible foams are in furniture and bedding, automotive seating and a wide variety of industrial applications.
INTEGRAL SKIN FOAMS
Integral skin foams are blown with at least one physical blowing agent, which, using a combination of overpack and correct mould temperature creates a densification of the surface, known as the skin.
Integral skin foams can be open- or closed-cell, flexible, semi-flexible or rigid. Integral skin foams are used in a broad range of applications in the automotive sector, and in furniture and cabinets.
FOAM FORMULATIONS AND RAW MATERIALS
Polyurethane systems are formulated from two major types of raw materials, polyols and diisocyanates.
Polyols are mostly polyether-based or polyester-based.
The most common diisocyanates are toluene diisocyanate (TDI) or 4,4′-methylenediphenyl diisocyanate or mixtures of polyisocyanates with 4,4′ diphenylmethane diisocyanate as the main component (polymeric MDI).
Other components in polyurethane systems are additives, i.e. catalysts, surfactants and blowing agents.
