SN/T 3896.8-2020Import and export textiles-quantitative analysis of fibers-near infrared method - Part 8: Mixture of cotton and polyamide (English PDF)

Foreword

The SN/T 3896 "Near Infrared Method for Quantitative Analysis of Import and Export Textile Fibers" includes the following parts.

--Part 1: The mixture of polyester fiber and cotton;

--Part 2: The mixture of polyester fiber and polyurethane elastic fiber;

--Part 3: The mixture of polyamide fiber and polyurethane elastic fiber;

--Part 4: The mixture of cotton and polyurethane elastic fiber;

--Part 5: Mixture of polyester fiber and viscose fiber;

--Part 6: Mixture of polyester fiber and polyamide fiber;

--Part 7: Mixture of polyester fiber and polyamide fiber;

--Part 8: Mixture of cotton and polyamide fiber;

This part is part 8 of SN/T 3896.

This part was drafted in accordance with the rules given in GB/T 1.1-2009.

This part is proposed and managed by the General Administration of Customs of the People's Republic of China.

Drafting organizations of this section. Zhongshan Customs, Nanchang Customs, Guangzhou Customs and Ganzhou Customs.

1 Scope

This part of SN/T 3896 stipulates the principle, equipment,, and equipment for the rapid determination of fiber content in cotton and polyamide mixtures by near infrared spectroscopy.

Sample and environmental requirements, measurement procedures, result processing, test reports.

This part is applicable to the rapid measurement of fiber content in cotton and polyamide fiber blended fabrics other than coated fabrics and pigment printing fabrics.

It is determined that the cotton content of the sample is between 0% and 100%.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 2910.1 Textile Quantitative Chemical Analysis Part 1: General Test Rules GB/T 2910.7 Quantitative Chemical Analysis of Textiles Part 7: Mixture of Polyamide Fiber and Certain Other Fibers (Formic Acid Method) FZ/T 01057 (all parts) Textile fiber identification test method

3 Terms and definitions

The following terms and definitions apply to this document.

Calibration model

The mathematical model of the relationship between the near-infrared spectrum of the sample and the corresponding chemical standard value established by the chemometric method, the calibration model Including qualitative models and quantitative models. The qualitative model is based on a large amount of information and data, based on expert experience and existing knowledge, Use the methods of computer and mathematical reasoning to complete the process of automatic identification and evaluation of shapes, patterns, curves, numbers and graphics; quantification the model is a mathematical relationship established between the concentration of a substance (or other physical and chemical properties) and the response value of the analytical instrument.

Note. The near-infrared qualitative model of the mixture of cotton and polyamide fiber is the identification model to determine whether the sample contains cotton and polyamide fiber. Cotton and polyamide the near-infrared quantitative model of the mixture of amine fiber, that is, the establishment of the near-infrared spectrum of the mixture of cotton and polyamide fiber using chemometric methods the mathematical relationship between the sample fiber content obtained by the standard method (GB/T 2910.1, GB/T 2910.7).

Homogeneous sample

The sample of any organization structure composed of a blending ratio (except for the core-spun yarn) or the difference between multiple measured values at different points on the front and back no more than 3% of the samples, the others are non-homogeneous samples.

Monitor samples

Homogeneous samples of the same species used to monitor the stability of the daily work of the near-infrared spectrometer.

Note. This sample is an essential accessory for a near-infrared spectrometer equipped with a cotton/polyamide fiber near-infrared analysis model.

Identification of fiber content the nominal value of the fiber content percentage of the textile to be tested, such as "35% cotton/65% polyamide fiber", "75% cotton/25% polyamide fiber".

4 Principle

The near-infrared spectrum of textiles reflects the chemical properties of CH, OH, CO, etc. in textile fiber molecules after textiles absorb near-infrared light.

The over-frequency vibration or rotation of the bond reflects the absorption characteristics of the near-infrared light of the textile; the chemometric method is used to establish cotton and polyamide the standard method of measuring the fiber content of the fiber mixture and the calibration model between the near-infrared spectroscopy, so that through the calibration model, the measurement Test the fiber content of the blend of cotton and polyamide fiber.

5 Equipment

5.1 Near-infrared spectrometer. Fourier transform type near-infrared spectrometer or raster scanning type optical fiber spectrometer.

5.2 Sampling accessories. rapid determination of textile fibers equipped with photosensitive devices-near infrared spectroscopy sampling accessories (see appendix A), the device Set the mass to (1 500~1 700) g.

Note. When using a Fourier transform near-infrared spectrometer for sample measurement, in order to determine the thickness of the sample to be tested, this sampling accessory should be used;

This sampling accessory is not required when measuring samples with a tracing type optical fiber spectrometer.

6 Sample and environmental requirements

7 Measurement procedure

8 Test report

The test report should include (but not limited to).

--The name and number of the calibration model;

--The scope of use of the calibration model;

--Instrument model;

-The name and number of the sample;

--Ambient temperature and humidity during sample test;

--The result of the sample measurement;

--Using the determination method standard;

- When there is a suspected sample, the type of the suspected sample and relevant information about its handling shall be provided;

--Testers and test time;

-All details that are not specified in this section, or deviate from this section, and may affect the measurement results.

Appendix A

(Normative appendix) Fast determination of textile fiber--principle of sampling accessory by near infrared spectroscopy and schematic diagram of accessory

Figure A.1 Rapid determination of textile fiber-schematic diagram of sampling accessory by near infrared spectroscopy

Figure A.2 Rapid determination of textile fibers-schematic diagram of sampling accessories for near infrared spectroscopy

Appendix B

(Informative appendix) Cotton/polyamide fiber calibration model parameters B.1 Near-infrared spectrometer and technical parameters Fourier transform near-infrared spectrometer, light source is tungsten lamp, detector is Peltier cooled indium gallium arsenide detector, scanning range is (4 000~10 000) cm-1, the resolution is 8 cm-1, the number of scans is 32 times, the signal-to-noise ratio is 10 000.1, and the wavelength is accurate ±0.2 cm-1;

Raster scanning optical fiber spectrometer, the spectral range (1 000~1 800) nm, the detector is an indium gallium arsenide detector, and the wavelength accuracy is ±0.2 nm, wavelength repeatability is <=0.05 nm, resolution is 2 nm, scanning times is 10 times, with optical fiber.

B.2 Quantitative model B.2.1 Quantitative model of Fourier transform near infrared spectrometer the near-infrared quantitative model of cotton/polyamide fiber is established by partial least square method. The specific parameters of the model are shown in Table B.1.

table...