Document rpVEo1MBXmKR3ZQnEJ11MmZ5a

from Virginia Pitts at (slew Haven subject poLYV|NYL CHLOR|DE _ Current Awareness NHTIS 71-30 Supplement II Project 8625-001 COPY TO D. Goodman M. Lapkin (2) J. H. Ludes C. W. MacMullen R. E. Maize!) M. A. Raymond D. Ryker T. R. C. (4) Attached is our most recent collection of patents and articles on polyvinyl chloride. We have also included a few references on Toxicology problems in the vinyl chloride area. As in the past, we will obtain copies of abstracted articles or full copies of those in which only the first page has been included as you request them. Sources: British Plastics - March 1971 Flooring - April, May 1971 F&S Index of Corporations and industries - March 2-May 4, 1971 Modern Plastics - April - May 1971 Plastics and Rubber Weekly - March - April 1971 Plastics Technology - April 1971 Plastics World - April-May 1971 SPE Journal - April-May 1971 OLI 7528 WHY FILE THIE COFYf IF YOU MUST RETAIN IT. SPECIFY A DEFINITE RETENTION PERIODl ONE YEAR OTHER. PLASTICS it RUBBER WEEKLY: January 29, 1971 TO)1*1 [0 Lf 1 Li uu PAGE 19 ARE plastics a fire hazard? How can die hazards be assessed? How can they be ameliorated? A good basis to start from is an article by Dr Helmut Birkner and Dr Klaus Diebel, in German, in the house journal of Chemische Werke Hills, called Der Lichtbogen. The article begins from the viewpoint of plastics in building construction, notes the confusion--as in Britain -- in terminology arising irom the lack of definition, and goes on to the German standard classification of building materials, in DIN 4102, which groups the com bustibles into three groups: difficult to burn, easy to burn, and something be tween the two. The DIN test is described and it* is noted that various matei ials fall into various groups. For some building purposes, only the highest group is permitted, `difficult iu burn wi-.htn the meaning of DIN 4102'. Rather than translate the a nbiguous German into equally ambiguous English, it is better to begin at the beginning. AM organic compounds hav ing.. carbon: carbon or carlion: hydrogen bonds arc combustible: it is inherent in the molecule and differs mainly in temperature. That may not be saying much that is helpful when you consider how com bustible even metals can be. But it does mean that there can be no actual incombus tibility of organic polymers, whatever treatment you give them. , What is useful to remem ber about polymers is that there is a wide range of combustibility, of ignition tiuuperatures, of continuity by CHARLES JENNINGS extinguishing. Also, remem looked at from the point of ber that It takes two to make view of the essential require a fire: the substance that ments of a good fireproofing burns and the atmosphere it agent (reduction of burning, burns in. no deleterious effects on pro From these considerations cessing or working, no degra has been devised a test, dation of physical properties, called the oxygen index of and non - toxicity,) com inflammability. Oil, which promises are often neces has proved to be one of the sary. most precise and re Flameproofing agents, like producible of the several in dices of flammability or com bustibility yet developed.for polymeric materials. Essentially, the index is halogen--, phosphorous--. and antimony containing compounds are considered in some detail by the authors who present an interesting Ihe percentage concentration table of the flameproofing of oxygen, in a mixture of substances referred to in oxygen and nitrogen, which recent patent specifications. will just sustain equilibrium burning of the material un der test Three types In an article in Der Licht bogen, the authors call it the They are classified into 'J' oxygen index anth quote three types: (1) organic ad figures like:-- ditives like chlorinated paraf ptfe ........................ 0.95 fins, bromine compounds, and pvc ........................ 0.45 halogen phosphates, (2) in pc ........................... 0.26 organics like antimony tri- pp ........................ 0.17 oxide, zinc and barium pe .................... 0.17 borates, (3) synergists like it will be noticed that the peroxides and hydra/.ine. earth's 'atmosphere -- with Of course, proportions are which we are almost always crucial and the form of the concerned in cases of fire -- polymer -- fitm, foam and has a J figure of 0.21, so block -- is important. that pc will not just burn in An important part of the air under ordinary con paper is devoted to test ditions, but pp and pe will. methods. Differential thermal Those J figures are for the analysis (DTA) and thermo- uncompoundcd polymers but gravimetry (TGA) give the they can be substantially most fundamental insight raised by adding suitable into what goes on during `fireproofing' agents. burning, but the more Birkner and Diebel discuss simplified and practical tests, such agents, dividing them generally imitative of the Into throe clones: filler ad special condition* of each ditives, reactive ingredients, situation, differ so widely In and after treatments. The the conditions of testing and reactive ingredients are. assessment of results that broadly, the most potent and HUU have' been forced to the most popular, giving an design their own test for in-built protection. their development work measuring and improving the burning characteristics of plastics are fined down to the small area of a single material, polyurethane, and a single form of that material, flexible foam, they seem to be only a little easier to solve. That is the general mes sage of the paper by R. M. Pruitt in Journal of Cellular Plastics, November/December 1970, pp. 262-6, on the self extinguishing characteristics The cause seems to be that the mixture produces a foam which, on ignition, melts and flows away but then chars and so insulates the foam from the heat of the flame. This effect leads on to the idea--an old one--of using incombustible, inorganic sub stances, incorporated by soaking the finished foam in a suitable solution or dis persion, followed by drying out of flexible urethane foam. Pruitt recommends In opening his paper, the 1 MgNHiPOi and the similar author thrashed about over calcium salt, both of which the same ground of am are cheap and effective biguity and lack of definition, although expensive to in as worried the German corporate. authors, pointing out that Pruitt concludes with an 'of some fifty tests for . flexible foams, none con- j sistcntly correlate with foam . in service conditions'. ; Pruitt also classifies flame- ; resistance treatments into three kinds: (1) intumescenl, shielding materials, (2) dilut ing fillers, (3) chemical inter ference with the burning. The last has been the traditional approach, generally involving halogen- and/or phosphorus-containing compounds. But Pruitt makes two valuable points not men- | tioned by the Germans. These are that bromine is ! more efficient than chlorine 1 and that both have a syner- I gistic effect with phosphorus. ( A large part of the paper is, ; in fact, devoted to examin- ' O ing the relationships between these three elements. Physical effects on the rate of burning must not be over looked. They are very ob CO vious in urethane foam when comparing the results of using different typos of iso cyanate, such as TDI and MDI. Each of these, used alone, produces foams which are not self-extinguishing, yet. used together, the produco a foam which 1* self examination of how far a practical burning test -- a small, uncovered cushion of the foam, ignited by a sheet of burning newspaper -- cor relates with the standard laboratory lest ASTM D1G92. Correia lion was indeed so poor that Pruitt pointedly remarks: `we must ask our selves if we want to con tinue playing the test-passing game.' This final judgment may not be entirety acceptable because the `service test' it self is not above suspicion, being not really representa tive of what actually happens lo an upholstered seat when there is a fire in a room or a vehicle. 9 t