All four blowing
agents yielded properties generally similar to HCFC-22 blown foam.
Session 4 on foaming polyurethanes will include the following presentations: "HFC blowing
agents for rigid insulation foams," Lotbar Zipfel and Christoph Meurer, Solvay Fluor, Germany; "Recent developments in the use of HFC-245fa blowing
agent for rigid polyurethane foam," Saskia Walraedt, Honeywell, Belgium; "New developments in applications of methylal as blowing
agent for rigid, flexible, integral skin and microcellular polyurethane foams," Michel Beaujean, Lambiotte & Cie, S.
Figure 4 shows time snapshots of the calculated core blowing
Session D on "Blowing
agents" will explore developments in zero ODP (ozone depletion potential) blowing
agents for the rigid foam industry.
Isotron line of HCFCs used as physical blowing
agents for PUR, PS, and PE.
In closed-cell foams, the ever-changing climate for blowing
agents is said to require quick and accurate measurements of heat transmission, and state-of-the-art data acquisition is essential.
As the uncured slab expands (from thermal expansion, curing or sponging caused by blowing
agents), the probe rides on the sample surface and a read-out of the expansion is graphed on the TA recorder.
Highlighting new BA-14 CoEx system, claimed to be the industry's largest six-layer coex machine designed for lab use, and the new tandem-blow process for simultaneous top and bottom blowing
of two bottles per parison, tail-to-tail.
As the blades pull back and blowing
is completed, the plastic self-seals and forms a ribbed structure.
The conversion to "cleaner" blowing
agents in the polyurethane foam business is largely done, and now much effort is being directed toward optimizing formulations to deliver better foams that are also easier to process and lower in cost.
In addition to these exothermal products, a separate line of endo-thermal blowing
agents is available.