- Email: [email protected]
New technology for assessing HCFC replacements
Fehruay
I!298
Nitrogen compounds are mainly used in the rubber industry and their growth is largely determined by the overall growth of the rubber industry, which is mature and dominated by tyres. Thioesters, which are slowest in growth, are used in much the same way as phosphorus, blended with other antioxidants to produce a variety of synergistic effects. Contact: Business Commicnications Co Inc, 25 Van Zant Street, Norwalk, CT 06855, USA; tel: + I-203 853 4266; fax: -CI-203 853 0348
EQUIPMENT System gives “unsurpassed” polymer characterization A new triple detection system, claimed to give “unsurpassed” characterization of polymer systems, has been introduced by Polymer Laboratories, UK. The PL-GPC210 is claimed to be the only truly integrated GPC/SEC system designed to incorporate any or all of the functions of absolute MW (molecular weight) light scattering, viscosity and high-performance refractive index detection. It will operate on polymers from ambient temperature to 210°C. In addition to carrying out GPC/SEC analysis, the system can accurately perform, from a single run, the following calculations: absolute MW, radius of gyration, determination of long chain branching and intrinsic viscosity. A key tectors highly heated system
advantage of the system is that all deand columns are situated inside a controlled oven environment without transfer lines, cold spots or excessive tubing or dead volume.
Contact: Polymer Laboratories Ltd Essex Road, Church Stretton SY6 6AX, UK; tel: +44-1694 72358I;.fax: +44-1694 722171
0199X Elsevier Science
Additives fbr Polymers
NEW TECHNOLOGY New technology for assessing HCFC replacements New experimental technology has been developed by Bayer Corporation USA in the search for new, environmentally safe polyurethane foam systems. Following the agreement to phase out CFC blowing agents, a number of candidates has been evaluated as potential replacements. with varying degrees of satisfaction, depending on the type of foam. Rigid foam has been the problem In recent years, however, HFC-24Sa has emerged as the leading potential replacement for HCFC-14 1b in rigid foams (which have excellent thermal insulation properties and are widely used in refrigerators and freezers). From July 2001, when US energy standards will become 25-30% more stringent, it is likely that foams produced with a replacement such as HIT-24Sa will not only have to match HCFC-14 1b foams, but actually outperform them. To reduce the k-factor (insulation value) of the foam, Bayer therefore set the target of identifying the input variables affecting the desired physical properties. In ten separate experiments on Bayer’s foam machine, the level of catalysts, processing temperatures of both masterbatch (resin) and isocyanate, and viscosity of the formulation were varied. The effects on the physical properties (k-factors at 2”C/35”F and 24”C/75”F, minimum fill density and freeze stable density, percent overpack to. freeze stable density, demould properties and gel time of the foam) were then compared with a previously reported fHFC-245a system and a commercial HCFC- 14 1b system. The experiments were designed to optimize variables to produce the required information with a limited number of experiments Contact: Bayer Carp, 100 Bayer Road Pittsburgh, PA I52059741, IJSA. tel: +1-412 777 2000
I!298
Nitrogen compounds are mainly used in the rubber industry and their growth is largely determined by the overall growth of the rubber industry, which is mature and dominated by tyres. Thioesters, which are slowest in growth, are used in much the same way as phosphorus, blended with other antioxidants to produce a variety of synergistic effects. Contact: Business Commicnications Co Inc, 25 Van Zant Street, Norwalk, CT 06855, USA; tel: + I-203 853 4266; fax: -CI-203 853 0348
EQUIPMENT System gives “unsurpassed” polymer characterization A new triple detection system, claimed to give “unsurpassed” characterization of polymer systems, has been introduced by Polymer Laboratories, UK. The PL-GPC210 is claimed to be the only truly integrated GPC/SEC system designed to incorporate any or all of the functions of absolute MW (molecular weight) light scattering, viscosity and high-performance refractive index detection. It will operate on polymers from ambient temperature to 210°C. In addition to carrying out GPC/SEC analysis, the system can accurately perform, from a single run, the following calculations: absolute MW, radius of gyration, determination of long chain branching and intrinsic viscosity. A key tectors highly heated system
advantage of the system is that all deand columns are situated inside a controlled oven environment without transfer lines, cold spots or excessive tubing or dead volume.
Contact: Polymer Laboratories Ltd Essex Road, Church Stretton SY6 6AX, UK; tel: +44-1694 72358I;.fax: +44-1694 722171
0199X Elsevier Science
Additives fbr Polymers
NEW TECHNOLOGY New technology for assessing HCFC replacements New experimental technology has been developed by Bayer Corporation USA in the search for new, environmentally safe polyurethane foam systems. Following the agreement to phase out CFC blowing agents, a number of candidates has been evaluated as potential replacements. with varying degrees of satisfaction, depending on the type of foam. Rigid foam has been the problem In recent years, however, HFC-24Sa has emerged as the leading potential replacement for HCFC-14 1b in rigid foams (which have excellent thermal insulation properties and are widely used in refrigerators and freezers). From July 2001, when US energy standards will become 25-30% more stringent, it is likely that foams produced with a replacement such as HIT-24Sa will not only have to match HCFC-14 1b foams, but actually outperform them. To reduce the k-factor (insulation value) of the foam, Bayer therefore set the target of identifying the input variables affecting the desired physical properties. In ten separate experiments on Bayer’s foam machine, the level of catalysts, processing temperatures of both masterbatch (resin) and isocyanate, and viscosity of the formulation were varied. The effects on the physical properties (k-factors at 2”C/35”F and 24”C/75”F, minimum fill density and freeze stable density, percent overpack to. freeze stable density, demould properties and gel time of the foam) were then compared with a previously reported fHFC-245a system and a commercial HCFC- 14 1b system. The experiments were designed to optimize variables to produce the required information with a limited number of experiments Contact: Bayer Carp, 100 Bayer Road Pittsburgh, PA I52059741, IJSA. tel: +1-412 777 2000