The textile and apparel testing technology mainly includes fiber content analysis and inspection, chemical analysis inspection, down inspection, color fastness inspection, physical index inspection and other aspects. The following 23 hot issues will be shared in 5 sections.
Section 1 Fiber content detection
Question 1: How to make qualitative and quantitative analysis for fabrics containing protein-modified polyacrylonitrile fiber?
Answer: The protein component of the protein-modified polyacrylonitrile fiber may change during the printing and dyeing process of the fabric. This change will bring difficulties to the qualitative identification of the fiber, especially the quantitative analysis of the fiber composition. When the common qualitative identification methods such as combustion method, microscopy method, dissolution method, and infrared spectroscopy cannot be accurately qualitative, the amino acid analysis method can be used in conjunction with the qualitative identification. When an abnormal dissolution phenomenon is found in the process of quantitative analysis using the dissolution method, the physical method may be preferred for quantitative analysis.
Question 2: When fabrics containing conductive fibers are tested for fiber content, can the test report include the name of the conductive fiber?
Answer: Conductive fibers and anti-static fabrics are recommended to use surface (or volume, etc.) specific resistance, anti-static performance and other items to test to prove their functions. As currently GB/T 29862-2013 "Identification of Textile Fiber Content" and standard reference documents do not have the name and definition of conductive fiber, it is not recommended to issue this name during fiber content testing.
Question 3: How to qualitatively identify metal coated fibers?
Answer: Observed under a microscope, metal-coated fibers have significant characteristics in both longitudinal and cross-sectional shapes, especially the longitudinal characteristics are more obvious, usually in a black opaque state, and the cross-section is a flat rectangle or nearly circular with black borders. The metal element analysis method can be used to test the metal content of the fiber to further confirm whether a fiber is a metal-coated fiber. If it is confirmed that the surface of the fiber is metal-coated by microscope method, metal content test method, etc., it can be issued as "metal-coated fiber".
Question 4: How to label the composition of artificial leather clothing fabrics?
Answer: It can be marked according to the following two standards. One is FZ/T 81018-2014 "Woven Artificial Leather Clothing" Standard 3.1 Instructions: "The artificial leather fabric should be marked with the main type of coating, and the instructions for the remaining finished products are in accordance with GB 5296.4."; The other is FZ/T 73028-2009 "Knitted Artificial Leather Clothing" Standard 4.1.1 "Artificial leather fabrics are only marked with artificial leather types, and the instructions for use of other products shall be implemented in accordance with the provisions of GB 5296.4", that is, artificial leather fabrics can only be marked with the main type of coating ( Types of artificial leather).
Question 5: How to identify POM fiber? How to issue a test report?
Answer: The use of qualitative identification methods such as dissolution method, melting point method, infrared spectroscopy and other qualitative identification methods can confirm that the chemical composition of the fiber is "polyoxymethylene". Before its uniform naming is not included in the standard of chemical fiber genus name, it is based on The provisions of B.5 in GB/T 29862-2013 "Identification of Textile Fiber Content" can be marked as "new chemical fiber", and if necessary, the manufacturer may be required to provide relevant certification materials.
Section 2 Inspection of down garments
Question 6: How to deal with the residual fat rate test in Appendix C of GB/T 14272-2011 "Down Clothing" when the results of two parallel samples are unbalanced and the difference is large?
Answer: It is recommended to refer to FZ/T 20018-2010 "Determination of Dichloromethane Soluble Substances in Wool Textiles" and GB/T 6504-2008 "Test Method for Oil Content of Chemical Fibers" Method A- Extraction Method: The test results are based on two samples The arithmetic mean of the two parallel tests is greater than 20%, the third sample test should be carried out, and the test results are expressed as the arithmetic mean of the three tests.
Question 7: When preparing the down cleanliness and oxygen consumption test sample solution of GB/T 14272-2011 "Down Clothing", the down sample failed to be completely immersed in water after 30 minutes of shaking, and floated on the water. How to deal with it?
Answer: Filter according to the standard requirements, test the cleanliness and oxygen consumption of the sample liquid, and note in the original record such as "The sample is not completely immersed in water".
Question 8: In the GB/T 14272-2011 "Down Clothing" standard, the container volume of the odor test item has specific regulations, but there is no uniform requirement for the material, production requirements and the opening size of the lid. Determining factors lead to differences in the test results of the samples. In order to improve the accuracy and consistency of the test results, how should the container be selected?
Answer: The GB/T 14272-2011 standard is currently being revised, and the inspection method is still under discussion. The new version of GB/T 10288 (currently submitted for approval) may be cited. The new version of GB/T 10288 has clearly stipulated that the container for odor testing is 1000mL jar with lid.
Question 9: According to the method a of GB/T 14272-2011 "Down Clothing", the anti-drilling down test is to take samples directly from the clothes. In some down jackets, the gall cloth and the fabric are quilted together. During the test, should the two layers of cloth participate in the under-drilling test or separately?
Answer: To simulate the downhole condition in the taking state, the sample will not be processed except for the closed cut.
Question 10: How to carry out classification and rating in the inspection of carded tyres?
Answer: Chapter 4 of the standard GH/T 1020-2000 "Carded Tire" stipulates that the item of "sensory requirements" shall be carried out on the carded tyre in accordance with the text description of serrated cotton in GB 1103-1999 "Fine Cotton" and the grade physical standard. Grading. However, starting from September 1, 2013, GB 1103.1-2012 "Cotton Part 1: Sawtooth Processing Fine Cotton" has cancelled the "grade" indicator and changed it to "color grade", and the corresponding grade physical standard has also been cancelled (grade physical The standard is valid for one year, and now the country no longer produces and updates uniformly). Therefore, it is necessary to be cautious when inspecting and determining the raw cotton grade of carded fetus according to the standard GH/T 1020-2000 "Carded Tire".
Section 3 Chemical Inspection
Question 11: GB/T 21294-2014 "Methods for the Inspection of Physical and Chemical Properties of Clothing" Appendix E. The selection of octylphenol standard products in the content test of alkyl phenol (AP), whether it is necessary to indicate which standard product to choose in the test report type?
Answer: GB/T 21294-2014 Appendix E Alkylphenol (AP) content test, E.2.3 stipulates "nonylphenol and octylphenol standard products: purity>99%, various isomer mixtures". Because octylphenol has different isomers, the spectra given in this standard are not all spectra of octylphenol isomers, but only typical examples. Since the standard varieties or CAS numbers selected by various testing agencies are different, it is recommended to mark the CAS numbers of the corresponding standard substances in the test report.
Question 12: When will the internal standard be added in the test method of GB 19601-2013 "Limits and Determination of 23 Harmful Aromatic Amines in Dyestuff Products"?
Answer: The test found that the different addition time of the internal standard has a great impact on the test results. Compared with GB/T 17592-2011 "Determination of Banned Azo Dyes in Textiles", this method standard is inconsistent with the addition time of the internal standard, and the operation should be strictly in accordance with the standard. If there is any deviation, it should be noted.
Question 13: GB/T 2912.1-2009 "Determination of formaldehyde in textiles Part 1: Free and hydrolyzed formaldehyde (water extraction method)" method stipulates in sample preparation 7, "If the formaldehyde content is too low, increase the sample The amount is 2.5g to get the most satisfactory accuracy." How to understand that the formaldehyde content is too low? In which case should the sample size be increased to 2.5g?
Answer: The content is too low, that is, the content is close to the detection limit. In this case (for example, A product, the index value is ≤20mg/kg), the sample volume should be increased to 2.5g to improve the accuracy of the test.
Question 14: When testing leather or fur for formaldehyde, do the samples need to be processed for humidity control?
Answer: Although humidity control may lose some formaldehyde, it can avoid the problem of inconsistent results between testing agencies due to the large difference in humidity between north and south. According to 220.127.116.11 of GB/T 19941-2005 "Leather and Fur Chemical Test-Determination of Formaldehyde Content", the sample is air-conditioned (humidity conditioning) before weighing.
Section 4 Physical Inspection
Question 15: The FZ/T 73012—2008 "Bra" standard stipulates that the color fastness to rubbing is only tested in the vertical direction. Generally, the size of the side wings (including some cup fabrics) of the sample basically does not meet the sampling requirements for the color fastness to rubbing. The GB cited in this standard /T 3920—2008 "Textile color fastness test color fastness to rubbing" mentioned that the ISO 105-X16 rotary device can be used for small area printing. Can it be used as a reference?
Answer: In this case, if the length of the fabric satisfies the effective friction stroke, the two ends of the fabric can be spliced with other fabrics to complete the test, or the customer can be required to provide a fabric test. The test is not performed on the parts that cannot meet the sampling requirements. The test results of reciprocating friction and rotary friction in GB/T 3920-2008 "Textile color fastness test color fastness to rubbing" are different. At present, the rotary friction method cannot be used to replace the reciprocating friction method for FZ/T 73012— 2008 "Bra" rubbing color fastness test.
Question 16: Do I need to remove the stitches between the upper and lower layers for the color fastness test of the sandwich fabric?
Answer: For the integrated weaving sandwich fabric structure, as a whole test, there is no need to remove the stitches; if it is a quilted interlayer fabric and the quilting is dense, the stitches will damage the fabric, and it can also be used as an overall test. When using multi-fiber lining, test the surface layer and bottom layer separately; when using single-fiber lining, choose the lining and test method according to the composite fabric. For samples with a large quilting distance and the surface layer, bottom layer and interlayer are obviously separable when sampling, the color fastness of the surface layer and the bottom layer are tested separately.
Section Section 5 Physical Inspection
Question 17: How to determine the number of times of detergent addition in multiple washing tests?
Answer: If there are no specific detergent addition requirements in the standard, for continuous multiple washings and there is no drying program in the washing room, only add detergent during the first washing program; for multiple washing and drying cycles of washing once and drying once Test, you should add detergent every time you wash.
Question 18: When testing the mesh density of FZ/T 62014-2009 "Mosquito Nets", how to determine the vertical and horizontal direction of the sample? How to assess the mesh density of the mosquito net? Is this standard suitable for the assessment of the mesh density of woven mosquito nets?
Answer: The vertical and horizontal directions of the sample are usually determined according to the vertical and horizontal directions of the fabric; the net density of the mosquito net product standard assessment is based on the functions of anti-mosquito and ventilation. Product innovation may cause the vertical density to be greater than the horizontal density. Consider from a functional point of view. It is recommended that the number of holes per unit area be used for assessment when the standard is revised. This standard does not apply to the assessment of the vertical and horizontal mesh density of woven mosquito nets.
Question 19: How to choose the sampling location for seam strength test in GB/T 21294-2014 "Methods for the Inspection of Physical and Chemical Properties of Clothing"?
Answer: Take the hem seam at the test part of the top; the side seam at the trouser test part; the hem seam and/or side seam at the test part of the skirt, or take samples at the positions specified in the corresponding product standards.
Question 20: How to rate the water resistance and wetness test of laminated or coated fabrics?
Answer: Laminated or coated fabrics are tested in accordance with the GB/T 4745—2012 "Testing and Evaluation of Textile Waterproof Performance by Wetting Method." Observe the surface carefully from an angle to determine whether the surface is wet; for the wet test, if it is determined that the test surface is not wet and the reverse surface has water seepage, grade it according to the test surface, and note the water seepage/wetness of the reverse surface.
Question 21: Is the distortion rate of non-straight pendulum products evaluated after washing?
Answer: After washing, the distortion rate is only evaluated for straight pendulum products, and non-straight pendulum products are not tested.
Question 22: Using GB/T 3917.1-2009 to test the woven elastic fabric, the fabric is not completely torn, how to deal with the result?
Answer: This standard does not apply to woven elastic fabrics. If the customer requires testing, record the test value and remark such as "The sample is an elastic fabric and is not completely torn."
Question 23: Issues related to crack testing
①The sample is a fabric, and the sample preparation is made when the product standard (FZ/T 81007, GB/T 2660, etc.) is used: Since the above-mentioned product standard test object is the finished product, there is no need to provide the fabric sample preparation method. Because the needle, thread, and sewing process used in sample preparation have a greater impact on the test results, it is recommended that the customer submit the stitched sample for inspection.
②The crack test of fabrics with different organizational structures: samples are taken from different parts, and the results are listed by part
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