Basic knowledge of textile and clothing inspection and testing

 

    1) Main items:

 

    Color fastness to washing, color fastness to dry cleaning, color fastness to rubbing, color fastness to light, color fastness to perspiration, color fastness to water, color fastness to chlorine bleaching, color fastness to non-chlorine bleaching, color fastness to hot pressing Degree and so on.

 

    2) Basic content:

 

    Washing color fastness: The sample is sewn together with the standard lining fabric, washed, washed and dried, and washed under suitable temperature, alkalinity, bleaching and friction conditions, so that the test results can be obtained in a short time . The friction during the process is accomplished by rolling and impacting with a small bath ratio and an appropriate number of stainless steel beads. Finally, the standard lining fabric and the sample are graded with a special gray card for color fastness, and the test results are obtained. Different test methods have different temperature, alkalinity, bleaching and friction conditions and sample size, and the specific ones should be selected according to test standards and customer requirements. Generally, the colors with poor color fastness to washing are turquoise blue, brilliant blue, black scarlet, navy blue and so on.

 

    Color fastness to dry cleaning: Same as color fastness to washing, except that washing is changed to dry cleaning.

 

    Color fastness to rubbing: Put the sample on the rubbing fastness tester, rub it with a standard white cloth under a certain pressure for a certain number of times. Each group of samples needs to do dry rubbing color fastness and wet rubbing color fastness. The color stained on the standard rubbing white cloth is graded with a gray card, and the grade obtained is the measured rubbing color fastness. The color fastness to rubbing needs to be tested for dry rubbing and wet rubbing. All the colors on the sample must be rubbed.

 

    Light fastness: Textiles are usually exposed to light when they are in use. Light can destroy dyes and cause the well-known "fading", which makes colored textiles lighter and darker, and some color changes will also occur. , It is necessary to test the color fastness. The light fastness test is to put the sample and blue wool standard cloth of different fastness grades together under the specified conditions for sunlight exposure, and the sample and the blue wool The cloth is compared to evaluate the light fastness. The higher the blue wool standard cloth, the better the light fastness.

 

    Color fastness to perspiration: sew the sample and the standard lining fabric together, put it in the sweat solution, clamp it on the perspiration fastness tester, put it in an oven at a constant temperature, and then separate the lining fabric of the sample After drying, the standard lining fabric and the special gray card for color fastness of the sample are graded, and the test results are obtained. Different test methods have different perspiration liquid ratios, different sample sizes, and different test temperatures and times.

 

    Color fastness to water stain: The sample is stitched together with the standard lining fabric, and after being fully immersed in water under certain conditions, it is clamped on the perspiration fastness tester, placed in an oven at a constant temperature, and then the sample is attached to it. The lining fabric is dried separately, and finally the standard lining fabric and the special gray card for color fastness of the sample are graded, and the test results are obtained. Different test methods have different sample size, different test temperature and time.

 

    Color fastness to chlorine bleaching: After washing the fabric in a chlorine bleaching solution under certain conditions, evaluate the degree of color change, which is the color fastness to chlorine bleaching.

 

    Color fastness to non-chlorine bleaching: After the fabric is washed under washing conditions with non-chlorine bleaching, the degree of color change is evaluated. This is the color fastness to non-chlorine bleaching.

 

    Color fastness to hot pressing: After covering the dry sample with a cotton lining fabric, press it for a certain period of time in a heating device at a prescribed temperature and pressure, and then use a gray scale to evaluate the discoloration of the sample and the staining of the lining fabric . The color fastness of hot pressing includes dry pressing, wet pressing, and wet pressing. The specific test method should be selected according to different customer requirements and test standards.

 

 

 

    1) Main test items:

 

    Formaldehyde test, pH value test, water repellency test, oil repellency test, antifouling test, flame retardant test, fiber composition analysis, banned azo dye test, etc.

 

    2) Basic content:

 

    Formaldehyde test: A certain amount of free formaldehyde or released formaldehyde in a certain amount of fabric is extracted by a certain method, and then the formaldehyde content is calculated through a colorimetric test.

 

    In the current market, textile products can be finished with resin to improve the wrinkle resistance of the product. This resin finishing agent is directly synthesized from formaldehyde, so a certain amount of formaldehyde will remain on the fabric after finishing with these resins. In addition, in order to improve the color fastness, the crosslinking agent in the pigment printing paste and the fixing agent used after the dyeing of direct dyes and reactive dyes will cause a certain amount of formaldehyde to remain on the clothing materials. These formaldehyde can be measured by certain test methods.

 

    pH value test: Use a pH meter to accurately measure the acidity and alkalinity of the fabric solution. The value read on the pH meter is the measured pH value.

 

    Water-repellent, oil-repellent, and anti-fouling test: Use a certain method to test the resistance of fabrics to water, oil, and stains, mainly for fabrics that have undergone three-proof finishing.

 

    Flame-retardant test: Put the sample on the flame-retardant tester for burning according to the regulations, and see the flame spread time.

 

    Fiber composition analysis: Firstly, qualitatively analyze the fibers of the fabric. There are many types of qualitative analysis, including combustion method, melting point method, hand-sensing visual method, microscope section analysis method, etc. Generally, the microscope section analysis method is used, that is, the fiber section is sliced ​​with a slicer. After observing under a microscope, judging the type of fiber according to its appearance, and then qualitatively analyzing different fibers with different solvents to calculate the specific component content.

 

    Banned azo dye test: It is one of the most important quality control items in the international textile and apparel trade, and one of the most basic quality indicators of ecological textiles. At present, it is mainly analyzed and tested by gas chromatograph. There are three methods for azo dye testing, textiles (textiles other than polyester and leather), polyester (polyester), and leather (leather), so the ingredients of the product must be provided when doing the azo test. 

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