BCC Research Flame 2008 Conference Session2

Glade Squires, Ameribrom, Inc., Fort Lee, NJ

VECAP is a product stewardship initiative of the Bromine Science and Environmental Forum (BSEF) to address the very low levels of brominated flame retardants (BFRs) detected in the environment. Although the levels detected are well below those established as safe for both human health and the environment, detection is a cause for action. In response to this, BSEF established and launched the VECAP program initially for Deca-BDE in the EU and then in 2006 expanded the program to North America and other brominated flame retardants. The goal of VECAP is to identify, control, reduce and where possible, eliminate emissions of BFRs. Results to date, have demonstrated that VECAP is both a practical and cost effective means to voluntarily reduce emissions throughout the supply chain. The VECAP model is completely supported by the European regulatory authorities as a sustainable solution for managing brominated flame retardants.

2:00-2:30 p.m.
Brominated Aryl Phospholane Flame Retardants
Bob A. Howell, Y-J. Cho, Center for Applications in Polymer Science, Central Michigan University, Mt. Pleasant, MI

For most applications polymeric materials must contain flame retardant additives. Traditionally organohalogen compounds, particularily brominated aromatics, have been utilized in this application. They are generally readily available in relatively pure form at acceptable cost and are effective gas phase flame retardants. However, increasing concern about the accumulation of organohalogen compounds in the environment make the development of flame retardants that are effective at very low loading particularly attractive. Compounds that display two modes of action might impart sufficient flame retardancy at much lower levels than traditional organohalogen flame retardants. Brominated aryl phospholanes contain both bromine (for gas phase activity) and phosphorus (for solid phase activity). The carbon-carbon bond of these five-membered hetrocycles undergoes thermolysis at modest temperatures to generate a diradical capable of initiating polymerization of vinyl monomers. The resulting polymer contains flame retarding units in the mainchain.

2:30-3:00 p.m.
Synthesis and Properties of Flame-Retardant Epoxy Resins Based on Phosphacyclic Derivatives
Manfred Doering, Alexander Schaefer, Sebastian Seibold, Michael Ciesielski, Institute for Technical Chemistry, Research Center Karlsruhe, Karlsruhe, Germany

Epoxy resins are one of the most versatile classes of polymers with a great variety of applications. They are generally used as coatings, in fiber-reinforced composite materials, as casting resins and adhesives. Especially in electronic and electrical industries as well as aircraft and vehicle construction, fire resistance of these materials is of particular importance. Recently, phosphorus-modified epoxy resins have received most attention in literature as well as in industry too. Depending on the process engineering (prepreging, injection processes) different phosphorus derivates should be used. In principle, flame retardancy of epoxies can be achieved by using phosphorus additives, hardeners and epoxy preformulations. Since a phosphacyclic compound, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), was developed in the early 1970´s, a large number of applications and modifications of this flame retardant have been published. These systems are commercially applied for printed circuit boards and laminates. We developed syntheses of new heterocyclic and open-chain phosphorus compounds and introduce these molecules as additive as well as reactive components in epoxy resins with different hardeners and applications. In addition, we investigate the influence of sulphur or nitrogen in that molecules on the flame-retardant efficiency.

3:00-3:30 p.m. Coffee Break

Chairman: Bernhard Schartel, BAM Federal Institute for Materials Research and Testing, Berlin, Germany

3:30-4:00 p.m.
Zinc Stannates as Alternative Synergists in Flame Retardant Systems
G. Smart, A. R. Horrocks, D. Price, B. Kandola, Centre for Materials Research and Innovation, University of Bolton, Bolton, UK

Zinc stannates, including hydroxyl stannate, are used as a component within synergistic fire retardant systems usually in conjunction with halogenated species in a number of polymers. Their behaviour is similar to antimony III oxide (ATO) in that they enhance the effectiveness of the halogenated and, principally brominated retardant (Br-FR), present. Unlike antimony III oxide, they are relatively non-toxic and are specific in their synergistic activity. Thus zinc stannate/Br-FR interactions depend on the brominated (halogenated) species and probably also on the polymer matrix within which they are present. This paper reviews the published literature with regard to this synergistic specificity as well as the role of zinc stannates as synergists in halogenated polymers, notably poly(vinyl chlorifde), PVC. While unmodified PVC is self-extinguishing, in many applications organic plasticisers are added which provides additional fuel and so reduces the inherent flame retardancy conferred by the chlorine present, as seen by a significantly lowered LOI values, for example. When present in both flexible and rigid PVC formulations, zinc stannates give good additional fire retardancy and so may offset the effect of added plasticiser in the former. Published research shows that particle size is important with respect to efficiency and there is evidence of an increase in flame retardant properties when ultrafine particles of these tin-based fire retardants are used in the polymer formulations generally. Finally, the review will show that while there are concerns regarding the use of certain Br-FRs, which in some cases have led to their bans or restrictions on usage, coupled with toxicological issues regarding ATO, there are significant opportunities for zinc stannates. These are firstly as an ATO replacement in combination with selected Br-FRs of low environmental hazard as well as potential synergists with other flame retardant/polymeric formulations.

4:00-4:30 p.m.
New Flame Retardants for Polyesters based on Metal Phosphinates
Wolfgang Wanzke, Sebastian Hörold, Elke Schlossser, Clariant Produkte (Deutschland) GmbH, Division Pigments & Additives, Development Flame Retardants, Gersthofen, Germany

For the past few years, the new metal phosphinate flame retardants have been widely used in reinforced polyamides, mainly for electrical and electronic (E&E) applications. These products have gained market share in competition with halogen and red phosphorus based flame retardants due to the balanced property profile, compensating for some weaknesses of the other materials. Many original equipment manufacturers (OEMs) in the E&E industry request halogen free flame retarded components for their products and have set up road maps to phase out halogenated additives and PVC. Thermoplastic polyesters have proven to be very demanding materials for replacement of brominated flame retardants by other additives but in the meantime competitive formulations based on metal phosphinates have been developed. This paper presents new formulations for flame retarded polyesters and polyester based elastomers with comparative data on their profiles with regard to electrical, physical, processing and related properties. Since their industrial development in the late 1990s, metal phosphinates have been extensively investigated from a toxicological and environmental point of view. The set of data was further expanded during their market introduction since 2001 The metal phosphinate flame retardant is environmentally friendly and non-toxic. Therefore, it is not labeled as a hazardous substance according to regulations.

4:30-5:00 p.m.
The Effect of Zeolite-Based Waste Catalyst on the Flame Retardance of Thermoplastic Polyurethanes
Luciana R. M. Estevão, Agência Nacional do Petróleo, Gas Natural e Biocombustíveis-ANP, SCM, Rio de Janeiro, Brazil; Luciana G. Bastos, Milene L. A. Desmarais, Escola de Química, UFRJ, Rio de Janeiro, Brazil; Michel Le Brás, Services Généraux, Ecole Nationale Supérieure de Chimie de Lille, USTL, Villeneuve d'Ascq Cedex, France; Regina S. V. Nascimento, Instituto de Química - DQO, UFRJ, Rio de Janeiro, Brazil

Thermoplastic polyurethanes (TPU) are responsible for approximately 30% of thermoplastic elastomer consumption in the current market and its demand tends to increase. However, the high rates of accidents due to its high flammability points to the necessity of developing new flame retarded systems. Previous studies have shown that the the zeolite-based spent oil refinery catalyst (MEC) presents a flame retardancy enhancing effect when added to an intumescent mixture of ammonium polyphosphate (APP) and pentaerythritol (PER) in ethylenic copolymers. This work considers the use of MEC as an additive to the intumescent mixture in order to confer better flame retardance to TPUs. Four types of TPU materials, with different hardness, have been tested: 74-A, 95-A, 65-D and 75-D. Given that polyurethane is a carboniferous agent itself, only the APP was used as intumescent additive. The APP/MEC ratio used was 30:5 which, according to previous results1, gave the best results. The studied systems (Pure TPU, TPU + APP, TPU + MEC and TPU + APP + MEC) were analyzed through heating microscopy, Limiting Oxygen Index (LOI), thermogravimetric analysis (TGA) and UL-94 tests. The results have shown that APP or MEC, when used individually, do not increase the LOI values, but when combined, they can provide a synergistic effect. Heating microscopy and TGA results have confirmed the synergy observed with the LOI tests. They have shown char formation and lower mass loss at temperature of 800ºC. Another effect observed with the MEC and APP addition was the modification of the viscosity of the material, since they prevented the TPU from dripping, improving its classification from V2 to V0 in UL-94 test. This study shows the great potential for the spent oil refinery catalyst as an additive for flame retarded TPU.

5:00-5:30 p.m.
Some New Halogen-free Flame Retardants for Polyolefins
Yu-Zhong Wang, Center for Degradable and Flame-Retardant Polymeric Materials, College of Chemistry, Sichuan University, Chengdu, China.

Some new halogen-free flame retardants for polyolefins were synthesized. Their structures were characterized by FTIR spectra and 1H-NMR spectra, and different flame retardant formulations were designed to prepare flame-retardant polyethylene, polypropylene and EVA with good comprehensive properties, respectively. LOI, UL-94 and Cone calorimeter tests were used to evaluate the flame retardancy of those materials. The thermally decomposing behaviors and char layers of those materials were investigated using thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM) respectively. Some possible flame retardant mechanisms were proposed.

5:30-6:00 p.m.
Materials in Navy Applications
Usman Sorathia, NAVSEA, Carderock Division, West Bethesda, MD

There is a need for light weight materials in the next generation of U.S. Navy vessels. The newer light weight materials tend to be plastic or combustible in nature, and hence there is a concern for fire, smoke, and toxicity of these materials. In order to permit these new materials in the Navy construction, fire performance criteria has been established for many applications. This paper will discuss such criteria for innerspring mattress, blankets; thermal, acoustic, and fire insulation; composites for topside applications, gaskets, GRP piping, coatings, etc.

6:00-7:30 p.m.
Reception, all attendees invited

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