You are so right, never forget in any discussion involving EU legislation that this is the organisation that declared carrots to be fruit, and cucumbers over a certain length illegal to sell (but not if cut in half). Regards Mike -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of b_ellis Sent: Wednesday, August 14, 2002 1:42 PM To: [log in to unmask] Subject: Re: [TN] Bromine Joyce If I may be cynical, the EU don't STUDY anything, they just enact restrictions (examples: lead-free solder, trichloroethylene etc. to the power of hundreds). Brian joyce wrote: > > BRIAN, > are they going to take them back after use? (like the leadfree group > proposed for the lead containing solder). Does EU got a task group study > this? wow! I thought just the fire insurance goes up as side effect (as the > otherside argue about the health insurance goes down)... > > jk > > >-----Original Message----- > >From: TechNet [mailto:[log in to unmask]]On Behalf Of b_ellis > >Sent: Wednesday, August 14, 2002 2:16 AM > >To: [log in to unmask] > >Subject: Re: [TN] Bromine > > > > > >Joyce, > > > >Not to mention that the new stuffs (nitrogen- and phosphorus- organics) > >may leach just as much ... or more! > > > >Brian > > > >joyce wrote: > >> > >> Dave, > >> agree with you on the toxins... the engineering method is to > >determine what > >> is probability of burning at what temp. produce what kind of > >result. Most > >> of the Flame retardant product is UL 94-0 rating... as long as > >you replace > >> something with the same performance: corrosion, UL, material > >compatibility > >> etc.etc. and low cost...I am sure everybody would be happy. > >However, few of > >> the traps some of us went into are the "flashy" stuff, promise a lot, > >> implemented at the product level without sufficient test in real > >life data. > >> To replace a deficient product with an "unknown" is very scary. Costly > >> lesson to learn. > >> ...my 2.cents. > >> jk > >> > >> >-----Original Message----- > >> >From: TechNet [mailto:[log in to unmask]]On Behalf Of David Fish > >> >Sent: Tuesday, August 13, 2002 1:05 PM > >> >To: [log in to unmask] > >> >Subject: Re: [TN] Bromine > >> > > >> > > >> >Brian > >> > > >> >Bromine always seemed like such a 'nice' chemical, didn't it? > >> > > >> >Let me take you in a different direction. Brominated flame retardant > >> >incineration produces toxins: > >> >* polybrominated biphenyl ether (PBBE) > >> >* polybrominated biphenyl oxide (PBBO) > >> > > >> >Dave Fish > >> > > >> >----- Original Message ----- > >> >From: "b_ellis" <[log in to unmask]> > >> >To: <[log in to unmask]> > >> >Sent: Tuesday, August 13, 2002 5:14 AM > >> >Subject: [TN] Bromine > >> > > >> > > >> >> Yet once again, bromine has raised its head in a couple of recent > >> >> threads on this list. I'm beginning to question whether > >brominated fire > >> >> retardants are as bad as they are made out to be or whether they are > >> >> just painted bad. Unfortunately, my knowledge of polymer chemistry is > >> >> insufficient to form a judgement. Here is what I'm thinking: > >> >> > >> >> The basic manufacture of epoxy resins is in two stages, the > >> >> prepolymerisation and the crosslinking. I won't go into more than the > >> >> basics, as I know that the subject is very complex. The epoxy group is > >> >> provided by epichlorohydrin which is reacted with bisphenol A (BPA) in > >> >> the presence of an alkali (NaOH), the latter serving to > >react with the > >> >> liberated chlorine atom to form NaCl, during the > >prepolymerisation. Most > >> >> of the latter is removed for electrical grade resins, but some remains > >> >> (hence the high dielectric constant and poor power factors). > >> >> > >> >> The epoxy groups are subsequently reacted with cross linking > >agents for > >> >> the final polymerisation (curing) of the resin. Theoretically, if all > >> >> the components are stoichiometric, the resultant cured resin is > >> >> perfectly homogeneous with uniformly-sized molecules. In > >practice, this > >> >> is never perfect. > >> >> > >> >> The bromine comes in with FR-4 by using tetrabromobisphenol A > >(TBBPA) in > >> >> place of some of the BPA. This has the characteristic of releasing HBr > >> >> and Br2 when heated to combustion temperature, this, being heavy, > >> >> blankets the burning resin and excludes oxygen, thereby extinguishing > >> >> the flame. TBBPA is identical to BPA other than that 4 of the H atoms > >> >> are replaced by Br atoms, which are therefore covalently bonded to two > >> >> of the non-cyclic carbon atoms. There is therefore no question of any > >> >> ionic bromide being present in FR-4. Why then do bromide ions > >leach out > >> >> of FR-4, as has been proved time and time again? (Let's > >discount bromide > >> >> activated fluxes from this equation.) > >> >> > >> >> I have several thoughts on the matter: > >> >> a) could it be that the TBBPA is supplied with excess free Br atoms or > >> >> with brominated impurities that are less stable? > >> >> b) could it be that pressing temperatures already start a breakdown of > >> >> the TBBPA, allowing free HBr to float around the resin > >matrix? (This may > >> >> explain why FR-4 is marginally poorer electrically than G-10) > >> >> c) could it be that the NaOH is capturing some Br from the > >TBBPA during > >> >> prepolymerisation? > >> >> d) could it be that the TBBPA is astoichiometrically in excess, > >> >> providing an easily attacked molecule? > >> >> e) could it be that there are no free bromide ions at all, until our > >> >> extraction fluid hydrolyses some organobromine compound? (If > >this is so, > >> >> then our ion extraction/ion chromatography tests become less > >meaningful, > >> >> as providing a means of a reaction!) > >> >> > >> >> I think we need the thoughts of a specialist polymer chemist > >to obtain a > >> >> much better understanding of what is happening and its > >influence on the > >> >> reliability of our FR-4 substrated assemblies. > >> >> > >> >> Anyone any ideas???? > >> >> > >> >> Brian > >> >> > >> >> > >> > >>-------------------------------------------------------------------------- > >> >------- > >> >> Technet Mail List provided as a free service by IPC using > >LISTSERV 1.8e > >> >> To unsubscribe, send a message to [log in to unmask] with > >following text in > >> >> the BODY (NOT the subject field): SIGNOFF Technet > >> >> To temporarily halt or (re-start) delivery of Technet send e-mail to > >> >[log in to unmask]: SET Technet NOMAIL or (MAIL) > >> >> To receive ONE mailing per day of all the posts: send e-mail to > >> >[log in to 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previous posts at: > http://listserv.ipc.org/archives > > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional > > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > > ext.5315 > > -------------------------------------------------------------------------- > -- > > ----- > > > > -------------------------------------------------------------------------- > ------- > > Technet Mail List provided as a free service by IPC using LISTSERV 1.8e > > To unsubscribe, send a message to [log in to unmask] with following text in > > the BODY (NOT the subject field): SIGNOFF Technet > > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > > Search the archives of previous posts at: http://listserv.ipc.org/archives > > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional > > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > > -------------------------------------------------------------------------- > ------- > > -------------------------------------------------------------------------- -- > ----- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > 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