On one of the IKO web pages there is a description on how shingles are made.
From what I understand, the plastic is applied to the back of each shingle
so that it does not stick to the machine that is making them. Therefore, I
conclude that the shingles are probably being propelled between two rollers,
one on top and bottom. The one on top applies the tar to the shingle, but
as the shingle moves off the rollers the tar from the top roller can get on
the bottom one. This causes tar to get on the bottom of the shingle and the
plastic is applied to prevent the tar from getting on the other parts of the
machine and stops the shingles from sticking. Seems reasonable to me
anyway. Cheers, R
"Nehmo Sergheyev" wrote in message
news
- Joe -
But getting back to the IKO answer above - it doesn't explain what
these strips are covering up.

Their logic is that the tape is there to keep the shingles from
sticking to each other. Which means that what-ever is UNDER the tape
is sticky and shouldn't come into contact with other shingles while
bundled. So why put this stuff on the shingles in the first place?

- Nehmo -
Picture the shingle correctly oriented with the granular surface up.
What's UNDER the tape on the bottom of the shingle is the next shingle.
While in a package, the tape is above the adhesive spots of the next
shingle. While installed on the roof, the tape is above a part of the
next shingle where there is no adhesive because each shingle is offset
from the next shingle. Thus, the tape serves a function while the
shingle is in a package, but serves no function after the shingle is
installed.

The *other* adhesive on the bottom of a shingle that holds the tape on
only does that.

--
*********************
* Nehmo Sergheyev *
*********************