Appeal No. 2003-0401
Application 09/490,954
Specifically, the invention contemplates the
utilization of a single fiber glass facing sheet to
transport a previously formed half-thickness core
during the resin impregnating and prepreg curing
operations within a conventional horizontal treater;
the weight of the facing sheet and half-core
combination being adjusted so that by simply inverting
the combination on another combination with the half
cores thereof in engagement a final composite of
desired thickness is obtained after laminating under
heat and pressure.
The IBM Technical Disclosure Bulletin discloses a
multilayered sheet formed by cutting a roll of epoxy resin-
impregnated glass fiber cloth prepreg into rectangular sheets and
inverting alternate sheets to ensure neutralization of inherent
stresses of the glass fiber cloth during subsequent operations to
form a printed circuit board (page 1). Specifically, the IBM
Technical Disclosure Bulletin states (page 1):
Prepreg, used in the manufacture of multilayered
printed circuit boards, consists of continuous glass
fiber cloth impregnated with liquid epoxy resin which
is then dried to remove residual solvents. Rolls of
prepreg are cut into rectangular sheets, stacked and
interleaved with copper sheets to form a layup which is
placed under pressure, heat, and vacuum to cure the
epoxy to a rigid laminate. Because the laminate must
maintain good bonding between layers, particular
attention has to be paid to environmental conditions
and to the accuracy of the stacking operation which
requires the inversion of alternate sheets to ensure
neutralization of inherent stresses of the glass cloth
during subsequent lamination operations.
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