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On-Line Method to Measure Flow Number And Conversion During An Impregnation Process

IP.com Disclosure Number: IPCOM000120399D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Gotro, JT: AUTHOR [+2]

Abstract

Disclosed is a method that provides a direct measure of the degree of conversion, on-line during the impregnation process. Using established calibrations, the flow number is obtained. This is a much more accurate method compared to the present flow test (which is an off-line test) and allows for both process monitoring and closed loop process control.

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On-Line Method to Measure Flow Number And Conversion During An Impregnation
Process

      Disclosed is a method that provides a direct measure of
the degree of conversion, on-line during the impregnation process.
Using established calibrations, the flow number is obtained.  This is
a much more accurate method compared to the present flow test (which
is an off-line test) and allows for both process monitoring and
closed loop process control.

      The on-line monitor passes a laser beam through the moving web,
consisting of a thermosetting polymer/glass cloth composite (herein
referred to as prepreg).  The laser is tuned to a specific infrared
absorbance which directly monitors the change in a given chemical
species.  The moving web averages the absorbance variations due to
non-uniformities in the woven glass cloth.  The laser has sufficient
power to easily pass through the prepreg web twice, and still yield
adequate signal-to-noise for quantitative measurement of the
absorbance.  The laser is tuned to monitor a specific absorption that
is directly related to the degree of cure in the polymer.  This
absorbance is empirically related to the flow number.  This is an
improvement over the present flow test in that the laser method is
much more accurate, and is performed on-line in relatively short
times (30 second analysis time, maximum).  The present flow test is
performed off-line and requires 7 minutes.

      The lasers and detector assemblies are mounted at the exit of
the tower, but before the wind-up station.  In treaters with on-line
sheeters (prepreg slitting devices), the lasers and detectors would
be mounted to scan the web prior to the sheeters.  This would allow
direct sorting of in-spec and out-of-spec prepreg.

      One requirement on an on-line system is the...