Could the incidences of yellow banding across the displays of some new iPhone 4 handsets be down to rushed manufacturing and side-effects of the chemicals used in producing the new Apple smartphone? That's one suggestion today; buried in the discussion over at Apple Insider, one source claims the discoloration is down to the adhesive used to bond the layers of glass in the screen together. That adhesive - Organofunctional Silane Z-6011 - requires a period of drying time post-application; the source suggests that Apple - or their manufacturing partners - rushed through that process and that the blotches should disappear after a few days of use.
Apple is using a bonding agent called Organofunctional Silane Z-6011 to bond the layers of glass. Apparently, Apple (or more likely Foxconn) is shipping these products so quickly that the evaporation process is not complete. However, after one or two days of use, especially with the screen on, will complete the evaporation process and the yellow "blotches" will disappear.
How do I know? I was involved in pitching Z-6011 to Apple.
Now, we're neither chemists nor engineers, but there do seem to be multiple issues of the banding problem already reported at Apple's support site, and from what we've read of the bonding adhesive it's made clear that ethanol and silanol groups will be given off post-application and that manufacturers should allow either air-drying or forced-drying time for that to happen. Apple has reportedly experienced production delays in the run up to the launch, and has publicly confirmed that the white iPhone 4 is experiencing unforeseen manufacturing issues and won't be available until late next month. It's certainly possible that the demands of a very public launch date have forced Foxconn to rush the process somewhat.
Still, if the Apple Insider forum source is correct, the discoloration problem should fix itself as the iPhone 4 display sandwich dries out. Apple are still yet to publicly comment on the issue, though some support site users who initially experienced the yellow blotches are now saying that, having been using their handsets for a few hours (often in relatively warm climates), the patches are no longer visible.