Well, from what I can tell comparing the data sheets,
the ITEQ IT-158 has a LOWER peel strength than the Grace MTC-97,
(Iteq is around 7-8? Grace is 11?)

And if you are using low-profile copper clad, it will be even lower

sorry I can't help more than that,
Jack

.
On Thu, 12 Jan 2012 13:24:40 -0700, Woolley, Mark D. (Mark) <[log in to unmask]> wrote:

>Let me add a bit more information on this issue.  
>1.	The material we are having issues with is Iteq IT-158.  We are
>not seeing any issues with any of the other laminates we are using such
>as Grace 	MTC-97.  The Iteq material has higher Tg, Td and pull
>strength per specification than the Grace MTC-97 material.
>2.	The pad layout is identical across the product line.  This
>includes the distance to the edge of the panel.  The pads that are
>lifting are on the 	outside of the laminate.  No internal
>delaminations have been seen in the cross sections I have made. Internal
>delamination si not suspected 	because the product operates when it is
>connected back together.
>3.	The reflow profile is for Pb-free soldering using SAC305 solder.
>The peak temperatures, duration of the temperature and time above
>liquidus is the 	same on all reflow profiles of similar products.
>
>So I don't think the design is at fault, nor the processing at the
>assembly house.  The pads are for 8-pin RJ-45 jacks using a standard
>pattern.
>
>I am seeing a ring of cleared copper on the PWB side of the pulled pad.
>This is troubling me because I can think of no reason it should be there
>unless the etchant was able to get beneath the copper pad.  I can post
>an image if someone will be so good as to point me to the picture upload
>page. (much appreciated).
>
>
>mark
>Mark Woolley |PTRL Laboratory | Avaya | 1300 West 120th Ave |
>Westminster, CO 80234  USA |
>Voice (Lab): (303) 538-2166 | email: [log in to unmask] |
>
>

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