Halogen-free,flame-retardant PUF Clariant GmbH has obtained a United States’ patent for its invention relating to a halogen-free, flame-retardant rigid polyurethane foam (PUF), wherein a blend of oxalkylated alkylphosphonic acids and ammonium polyphosphate is present as flame retardant, and to a technology for its production. Oxalkylated alkylphosphonic acids are used in a mixture with ammonium polyphosphate for producing halogen-free, flame-retardant rigid PUF of this type. The same product can also be obtained by means of a process for producing a halogen-free, flame-retardant rigid PUF from polyisocyanates and polyols in the presence of blowing agents, stabilizers, activators and/or other conventional auxiliaries and additives. It comprises reacting organic polyisocyanates with compounds having at least two hydrogen atoms capable of reaction with isocyanates, in the presence of blowing agents, stabilizers and a flame-retardant combination of oxalkylated alkylphosphonic acids of the formula I and ammonium polyphosphate. The blowing agent is preferably water and/or pentane. Oxethylated alkylphosphonic acids of the formula I are preferably compounds that are liquid at processing temperature. Website: www.freepatentsonline.com Rigid PUF with reduced density BASF Aktiegesellschaft has obtained a United States’ patent for its process to produce rigid polyurethane foam (PUF) with reduced density. The production process involves reacting organic and/or modified organic polyisocyanates with at least one higher molecular weight compound having at least two reactive hydrogen atoms and, if desired, low molecular weight chain extenders and/or crosslinkers in the presence of blowing agents, catalysts and, if desired, other auxiliaries and/or additives. The blowing agent comprises a mixture of cyclopentane, at least one compound that is homogeneously miscible with cyclopentane selected from the group consisting of alkanes and alkenes having 3 or 4 carbon atoms in the molecule, and carbon dioxide produced from water and isocyanate, and wherein the higher molecular weight compound having at least two reactive hydrogen atoms comprise polyethers, which contain aromatics and nitrogen. The blowing agent mixture contains propane, n-butane, isobutane, cis-trans-2-butene and/or trans-trans-2-butene. About 0.1-10 per cent by weight of cyclopentane is used and the alkanes/alkenes having 3 or 4 carbon atoms in the molecule are used in an amount of 0.1-6 per cent by weight, based in each case on the entire amount of the foam. Website: www.freepatentsonline.com Additive for HFC-134a foam systems HFC-134a, an alternative to HCFC-141b in polyurethane foam applications, has limited solubility in polyurethane raw materials such as polyols. This issue can be alleviated by a careful selection of polyols and utilizing co-blowing agents, such as water. Researchers in the United States have studied the potential for utilizing trans-1, 2-dichloroethylene (TDCE), a liquid at room temperature with no ozone depletion potential (ODP) and very low global warming potential (GWP), with several HFC-134a-polyol combinations. Results indicate that the presence of TDCE can lower the vapour pressure of certain HFC-134a-polyol blends. More importantly, the presence of TDCE allows one to reduce HFC-134 levels, significantly lowering the overall vapour pressure of HFC-134a-containing systems. Finally, the presence of TDCE dramatically reduces the viscosity of HFC-134a-polyols blends, which is important for some applications. Website: www.cel.sagepub.com Production of polymer polyol The combination of high solids polyols and liquid carbon dioxide (CO2) blowing techniques required for making high load bearing polyurethane foams (PUF) can create operational issues for foam manufacturers. Shell Eastern Chemicals (Pte.) Ltd., Singapore, is offering a special filtration technique that ensures Caradol polymer polyols are compatible with the latest production methods. Liquid CO2 is the most effective and environmentally acceptable blowing agent used for producing PUF. This has placed increased demand on the performance of the polymer polyol on foaming machinery equipped for CO2. With CO2, the foaming mixture has to be kept under very high pressure until the point at which it is discharged or ‘laid down’. Foaming machines typically have small apertures in the discharge device for depressurizing the mixture immediately before the laying down process. These apertures can become blocked, however, due to the nature of the polyols, which contain small polymer particles held in a stable suspension. Larger agglomerates of particles can get stuck in the laying down device, causing blockage. Around 6 ppm of particles larger than 50 µm are enough to cause a problem. Particle size in the filtered SAN grades of Caradol does not exceed 25 µm, allowing smooth and continuous processing for long production runs. Foam physical properties are unaffected by the filtration. Contact: Shell Eastern Chemicals (Pte.) Ltd., Shell House, UE Square, 83 Clemenceau Avenue, Singapore 239920. Tel: +65 6384 8000. Website: www.shellchemicals.com “Green” foaming system Metecno-Aluma Shield, based in the United States, produces metal insulated composite panels using an ozone-safe blowing agent.  Pentane is being used in place of HCFC-141b.  The new foaming system provides several benefits, including zero ozone depletion potential and global warming potential. The pentane-based foaming system complies with the EPA ban on HCFC-141b, while providing a long-term environmental option. It is especially ideal for builders and specifiers who want to demonstrate their commitment to the environment. The pentane blowing agent used, Exxsol from ExxonMobil, is the winner of the EPA 2003 Stratospheric Ozone Protection Award. With regard to fire performance, the metal insulated composite panels have been tested in accordance with UL 723/ASTM E84 Tunnel Test and FM 4880 Full-Scale Corner Test standards and achieved a Class 1 rating.  Website: www.alumashield.com