Dennis:
I remember when we used to order it green, remember the Westinghouse material. It was called G-10 for a long time until they started using brominated resins, at least that's what I remember. Hence the FR (flame retardant)
Ciba kept the Pigments group.
I know some of the manufacturers out there use a green pigment, and you are correct it is loaded with Cl.
I have also seen a lot of work done with the yellow and blue. Probimer 52 had blue in the hardener to turn the yellow resin to green. The common yellow that is the cheapest, and most available is highly chlorinated, and will not allow anyone to pass the " halogen free" or should we correctly say halogen minimized standards.
So My point was it's not rocket science to get most of the halogen out when you make the mask blue. do you agree? ( of course this doesn't take into account the residuals in the epoxy, and other components, but that is only a minor portion of the total)
Of course they would use blue to symbolize green, makes perfect sense. Why use a green leaf that could be understood? Maybe they couldn't get a patent on a green leaf, so they used blue!
Russ Smith
-----Original Message-----
From: Dennis Fritz [mailto:[log in to unmask]]
Sent: Monday, April 07, 2003 2:00 PM
To: [log in to unmask]
Subject: Re: [TN] New Topic: Why are most solder mask requirements,for
GREENmas...
Couple comments on Russ Smith's posting:
1. I too heard that older laminate had a greenish hue, as the epoxy adhesion
promoter on the early glass fabric gave laminate a green tint (seems it was
chrome based, not silane?). Seems that 30 years ago, I remember the term
G-10, and not all was FR-4.
2. Slight correction on the pigments - blue is the color of non-halogen
phthalocyanine pigment, and green is the color when nearly fully chlorinated.
Think that is still the predominant blue/green pigment in many applications
- paints, inks, solder mask, etc. I have even heard that the environmentally
friendly Japanese symbol is a "blue leaf" symbolizing "green" ingredient
content. However, I have no confirmation. Russ, just a curious aside - Ciba
bought the DuPont blue/green pigment plant from DuPont in Delaware. It may
not have come into the Vantico fold, however.
Denny Fritz
MacDermid
---------------------------------------------------
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
-----------------------------------------------------
|
