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US 5,532,487 AGranted
Near-infrared measurement and control of polyamide processes
AssigneeE. I. Du Pont de Nemours and Company
InventorsAnn M. Brearley, Harvey S. Gold
Life of this patent
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Abstract
This invention relates to a method for the measurement and control of polyamides and polyamide precursor mixtures by means of near-infrared spectroscopy.
Claims13
A method for measuring and controlling at least one characteristic of a dimonomeric polyamide, copolyamide, or polyamide precursor mixture in a polymerization process stream, comprising the steps of:
- (a) creating a predictive model for the value of the characteristic;
- (b) acquiring spectra by measuring the near-infrared absorbance of the polyamide, copolyamide or polyamide precursor mixture in-line at least one selected point in the polymerization process stream at wavelengths within the near-infrared range;
- (c) applying spectral pretreatment to the measurements of step (b) to obtain a pretreated spectrum;
- (d) applying the predictive model to the spectrum to calculate a predicted value of the characteristic;
- (e) comparing the predicted value of the characteristic to a preselected desired value of the characteristic;
- and
- (f) controlling the characteristic by making an adjustment to at least one process variable of the polymerization process stream.
4 more elements
A method for measuring at least one characteristic of a solid phase dimonomeric polyamide or copolyamide and controlling said characteristic in a polymerization process stream, comprising the steps of:
- (a) creating a predictive model for the value of the characteristic;
- (b) acquiring spectra by measuring the near-infrared absorbance of the polyamide or copolyamide at-line within the near-infrared range;
- (c) applying spectral pretreatment to the measurements of step (b) to obtain a pretreated spectrum;
- (d) applying the predictive model to the spectrum to calculate a predicted value of the characteristic;
- (e) comparing the predicted value of the characteristic to a preselected desired value of the characteristic;
- and
- (f) controlling the characteristic by making an adjustment to at least one process variable of the polymerization process stream.
4 more elements
Dependencies are inferred from the claim text.