Optics: measuring and testing – By dispersed light spectroscopy – With raman type light scattering
Reexamination Certificate
2001-09-27
2004-03-23
Smith, Zandra V. (Department: 2877)
Optics: measuring and testing
By dispersed light spectroscopy
With raman type light scattering
C264S408000, C264S409000
Reexamination Certificate
active
06710869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a process for determining the dye uptake of polyethylene terephthalate fibres.
2. Description of the Related Art
A well-known, long-used method of determining the dye uptake of polyethylene terephthalate fibres is to employ a comparative test in which various fibre samples have their different uptakes of a standard dye determined. To this end small pieces of yam of different samples are knitted into a hose. Next, the hose is dyed with a dye critics to the material under critical conditions, i.e., the time during which the knitted hose is contacted with the liquid in which the dye is dissolved is too short to effect full saturation of the hose with dye or complete uptake of the dye from the bath. In addition, such a test employs dyes which have a slow uptake by the fibrous material in question, and the determination is carried out at a comparatively low temperature. The dye uptake is then evaluated visually by indicating whether a yam sample's dye uptake is superior, inferior or normal as compared with that of the yam sample next to it. Major drawbacks of this known method are that:
the results obtained are relative
the determination is dependent on the person carrying out the test
the method is complex and time-/labour-intensive
only comparatively large differences in dye uptake can be made visible
Admittedly, it is possible to do away with the subjective elements present in this determination by using photometric equipment (e.g., a HunterLab spectrometer), but it was found that in that case the knitted structure of the hose has a major effect on the determination.
For that reason there is great need for a method of swiftly and simply determining the dye uptake of polyethylene terephthalate fibres in such a manner as will enable an absolute comparison among the fibre samples. The invention now provides a process by which this requirement is satisfied fully or for the most part.
SUMMARY OF THE INVENTION
The invention consists in that in order to determine their dye uptake, the polyethylene terephthalate fibres are irradiated with high-intensity monochromatic light and a light-sensitive sensor is used to measure the Raman scattering and compare it with that of an earlier established model on the basis of Raman spectra of polyethylene terephthalate fibres of known composition and structure, whereupon a model is used to calculate the density, which constitutes a quantitative measure of the dye uptake, use being made in the calculation of measurement points from a number of regions within the spectral measuring range of 598 to 1900 cm
−1
, where out of a total number of measurement points of 100%:
a. 40-100% originates from the spectral region of category X,
b. 0-30% originates from the spectral region of category Y, and
c. 0-60% originates from the spectral region Q belonging to neither category X nor category Y,
the spectral regions of the categories X and Y, respectively, being formed by:
Category X
Category Y
704-714 cm
−1
796-802 cm
−1
876-890 cm
−1
1128-1132 cm
−1
984-1056 cm
−1
1292-1382 cm
−1
1086-1106 cm
−1
1596-1616 cm
−1
1172-1204 cm
−1
1398-1414 cm
−1
1434-1490 cm
−1
1690-1762 cm
−1
and the measurement points from the spectral region of category X originating from at least six out of the eight sub-regions of category X.
The invention also pertains to polyester fibres selected for uniform dye uptake by means of the aforementioned process.
REFERENCES:
patent: 3861129 (1975-01-01), Doschko
patent: 4156071 (1979-05-01), Knox
patent: 5849232 (1998-12-01), Ochi et al.
patent: WO 91/11695 (1991-08-01), None
patent: WO 99/12019 (1999-03-01), None
Furer, V. L., et al., “Band Intensities in Raman Spectra of Polyethylene Terephthalate and Model Aromatic Complex Esters,” Journal of Applied Spectroscopy, vol. 53, No. 4, pp. 1057-1061, Oct. 1990.
Wong, W. F., et al., “Analysis of the deformation of gel-spun polyethylene fibres using Raman spectroscopy,” Journal of Materials Science, vol. 29, No. 2, pp. 510-519, Jan. 1994.
Everall, Neil, et al., “Performance Analysis of an Integrated Process Raman Analyzer Using a Multiplexed Transmission Holographic Grating, CCD Detection, and Confocal Fiber-Optic Sampling,” Applied Spectroscopy, vol. 49, No. 5, pp. 610-615, May 1995.
Everall, Neil J., “Measurement of Orientation and Crystallinity in Uniaxially Drawn Poly(ethylene terephthalate) Using Polarized Confocal Raman Microscopy,” Applied Spectroscopy, vol. 52, No. 12, pp. 1498-1504, Dec. 1998.
De Weijer Anton P.
Swieringa Erik
Van Wijk Robert J.
Acordis Industrial Fibers GmbH
Oliff & Berridg,e PLC
Smith Zandra V.
Stock Gordon J
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