{"id":9193,"date":"2025-01-03T10:09:09","date_gmt":"2025-01-03T02:09:09","guid":{"rendered":"https:\/\/www.textile-fabric.com\/archives\/9193"},"modified":"2025-01-03T10:09:09","modified_gmt":"2025-01-03T02:09:09","slug":"how-is-color-fastness-rated","status":"publish","type":"post","link":"https:\/\/www.textile-fabric.com\/?p=9193","title":{"rendered":"How is color fastness rated?"},"content":{"rendered":"
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Most of the current color fastness test methods are based on simulation tests or comprehensive tests based on the environment and conditions of action, and the fastness grade is evaluated based on the discoloration of the sample after the test and the staining of the lining fabric. What is special is that the color fastness to light is rated by the blue label, while the color fastness to dry cleaning will evaluate the staining by solvents. <\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n

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When rating color fastness, changes in the three attributes of color should be comprehensively assessed, that isChanges in hue, lightness and purity<\/span>.<\/span><\/span> p><\/p>\n

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\n1. Hue: Hue refers to the appearance of a color. Among the three attributes, hue can be used to distinguish colors. According to different wavelengths of light, colors have properties such as red, yellow or green, which is called hue. <\/section>\n<\/section>\n
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\n2. Brightness: Depending on the degree of light reflection on the surface of the object, the brightness of the color will be different. The brightness of this color is called brightness. <\/section>\n<\/section>\n
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\n3. Purity: Purity refers to the degree of saturation of a color. The simpler the light wavelength, the higher the purity of the hue, and vice versa. <\/section>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n
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Color fastness rating can be divided intoGaze Rating and Instrument Rating<\/span><\/span><\/p>\n

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Gaze rating<\/span><\/p>\n

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It requires that the background should be neutral gray, approximately between level 1 and level 2 of this gray sample card (approximately Munsell color card N5). The lighting conditions should be northern daylight (9:00-15:00) on a sunny day, or an equivalent light source with an illumination of 600lx and above. The incident light is at an angle of approximately 45\u00ba to the textile surface, and the observation direction is roughly perpendicular to the textile surface. Cover the original and The color of the plate of the sample after the test should be consistent, preferably neutral color or gray or black, and the size and shape should be roughly the same. Rating personnel should wear neutral gray work clothes, and the rating process should avoid the influence of environmental colors. <\/p>\n<\/section>\n<\/section>\n<\/section>\n

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Color fastness rating:<\/span>After test sample and Compare it as it is and see that the degree of discoloration is close to that of the gray card. <\/span><\/p>\n<\/section>\n<\/section>\n

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Stain fastness rating:<\/span>Paper after trial Compare with the untested lining to get a close staining grade. <\/span><\/p>\n<\/section>\n<\/section>\n

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Instrument rating:<\/span><\/p>\n

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The principle of instrument rating is to use the absolute reflectance of a known standard white plate for calibration, measure the spectral power distribution of the sample reflection or its own reflectance photometric characteristics, and then calculate the object’s radiance under the standard illumination body based on the spectral measurement data. The tristimulus values, chromaticity coordinates, CIELAB uniform color space, etc. are converted into gray card series of discoloration and stain fastness through a series of formulas. <\/p>\n

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Sometimes when reading the report, you will have questions. Why is the test result of color fastness to soaping and discoloration shown on the test report level 3? When the standard requirement is \u22653-4, is it still judged as unqualified? Is the report judgment wrong? <\/p>\n

In fact, the result is correct. The color fastness evaluation grade 3-4 is not an interval in the general mathematical concept. It is a grade, which means that the test result is between grade 3 and grade 4. <\/p>\n<\/section>\n<\/section>\n<\/section>\n

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Attachment: Problems and solutions for unqualified color fastness<\/strong><\/p>\n<\/section>\n<\/section>\n<\/section>\n

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\n1 \uff0e Color fastness to water, washing and perspiration<\/strong><\/section>\n
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\n1) FAQ<\/span><\/section>\n
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Staining is not up to standard<\/span><\/p>\n

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\n2) Cause Analysis<\/span><\/section>\n
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The floating color on the cloth is related to the transfer of some colored fiber particles;

\nIt is related to the selected dye species, dyeing process and post-processing process;

\nAcetate and nylon have good coloring rates for a variety of dyes at lower temperatures;

\nThermal migration phenomenon when dyeing with disperse dyes;

\nWater has a plasticizing effect on spandex. Under wet conditions, the dye that enters the amorphous area of \u200b\u200bspandex can easily migrate to the fiber surface. Under the action of external force, the transfer of dye can easily occur, staining the lining cloth;

\nIn fact, in elastic fabrics containing spandex, the proportion of spandex filaments is quite low and is usually not exposed on the surface of the fabric. The color fastness problem of spandex will not seriously affect the color fastness of the entire fabric. The color fastness problem of spandex-containing elastic fabrics is mainly due to the color fastness problems of cotton, polyester, nylon and other fibers on the surface of the fabric itself;\u2019<\/span><\/p>\n

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\n3) How to improve<\/span><\/section>\n
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Improve fabric dyeing properties, such as dye penetration, sufficient color fixation, strengthen soaping, washing, reduction cleaning, and fully remove floating colors;

\nUse color-fixing agents to improve the fabric’s water resistance and color fastness to washing;

\nUse corresponding additives to prevent sweat from destroying the dye carrier structure<\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n

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\n2 \uff0e Color fastness to sunlight<\/strong><\/section>\n<\/section>\n<\/section>\n<\/section>\n
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\n1) Unqualified factors<\/section>\n<\/section>\n<\/section>\n<\/section>\n

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Fabric organizational structure;

\nMolecular structure of dye\u00b2;

\nThe bonding state of fiber and dye changes with dye concentration;

\nColor matching using dyes with different light fastnesses;

\nDyes with good diffusion properties and uniform penetration within the fiber have high color fastness to sunlight;<\/span><\/p>\n

Some additives applied to fabrics will affect the color fastness to sunlight;<\/span><\/p>\n

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\n2) How to improve<\/section>\n<\/section>\n<\/section>\n<\/section>\n

Choose the dye correctly

\nFormulate and implement reasonable dyeing process conditions to make the fabric dyed evenly and thoroughly and fully fixed; strengthen the avoidance of adverse effects of post-finishing

\nAfter dyeing, soap and wash to fully remove floating color

\nUsing light fastness enhancer

\nUse anti-UV finishing agents where appropriate<\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n

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\n3 .Chlorine bleaching and non-chlorine bleaching color fastness<\/strong><\/section>\n
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\n1<\/section>\n
\n1) Unqualified factors<\/section>\n
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Active chlorine reacts with dyes, causing oxidative decomposition of dyes;

\nPeroxide reacts with the dye matrix, causing the dye to change color or fade, or destroy the combination of the dye and the fiber;

\nThe color fastness of dyes to chlorine bleaching and non-chlorine bleaching is related to the dye structure;<\/span><\/p>\n

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\n2<\/section>\n
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Reasonably screen dyes and choose dyes with chlorine bleaching resistance and non-chlorine bleaching structureMaterial;

\nFully scouring before dyeing and washing after dyeing, strive to remove impurities and keep the fabric neutral, because the presence of impurities, acid and alkalinity will accelerate the decomposition of dyes under chlorine bleaching and non-chlorine bleaching conditions;

\nUse chlorine-resistant color fixing agent to improve the chlorine resistance of the dye and strengthen the combination of dye and fiber;

\nUse active chlorine capture agents to prevent dyes from being affected by active chlorine. The disadvantage is that most of these additives are not durable and are rarely used;<\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n

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\n4 .Color fastness of denim fabric to ozone<\/strong><\/section>\n
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1) Unqualified factors<\/span><\/p>\n<\/section>\n<\/section>\n

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Indigo will decompose into indigo under the action of strong oxidants, and ozone has a strong oxidizing effect;

\nIndigo should be red, but the phenomenon seen in the actual test is more yellowish, which is related to the purity of the dye used, other chemicals added in the dyeing process, the fabric and the finishing process;<\/p>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n

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2) How to improve<\/span><\/p>\n<\/section>\n<\/section>\n

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Choose dyes whose structure is resistant to ozone oxidation

\nAntioxidant and anti-yellowing additive<\/p>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n

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\n5 \uff0e Phenol yellowing<\/strong><\/section>\n
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White fabrics sometimes turn yellow during storage. The yellowed parts will disappear and return to their original white color after acid treatment. If alkali solution is added again, the yellow color will return. . The main reason is phenol yellowing. <\/span><\/p>\n

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1) Reason<\/span><\/p>\n<\/section>\n<\/section>\n

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The antioxidant BHT (2,6-di-tert-butyl-p-cresol) commonly used in packaging materials and nitrogen oxides (NOx) in the air A chemical reaction occurs to generate DTNP (2,6-di-tert-butyl-p-nitrophenol). DTNP is colorless in an acidic state and easily sublimates and transfers at room temperature. When encountering alkaline substances, it immediately turns yellow. . <\/span><\/p>\n

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2) How to improve<\/span><\/p>\n<\/section>\n<\/section>\n

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Use BHT-free packaging materials, such as PE film, wrapping paper and cartons

\nAdd low-volatile acids such as citric acid, oxalic acid or tartaric acid to maintain the acid pH value of the processed cloth at around 4.5 to 6.0

\nChoose additives that do not contain BHT and are not easily absorbed, such as weak cationic softeners\u00b2

\nAvoid air pollution and reduce NOx concentration in cloth processing and storage places

\nFluorescent whitening agent treatment (the acid and alkali resistance of the fluorescent whitening agent must be considered)<\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n

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\n6 \uff0e Color fastness of pigment printed fabrics<\/strong><\/section>\n
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Pigment printing: It is a printing method in which insoluble pigments are mechanically fixed on the fabric with the help of adhesive. <\/span><\/p>\n

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\n1) FAQ<\/span><\/section>\n
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Poor color fastness to dry and wet rubbing

\nThe printed surface is whitish

\nAfter the washability test, it was found that the printed parts were cracked, peeled off or even broken<\/span><\/p>\n

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\n2) Analysis of reasons for failure<\/span><\/section>\n
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Printing adhesives are divided into three categories: hard monomers, soft monomers and functional monomers. Adding more hard monomers will help improve printing The color fastness to rubbing will make the printed area feel hard and prone to cracking, the light resistance will steadily decrease, and it will easily turn yellow.

\nAdding too much soft monomer can improve the feel and light resistance, but the film strength is too low, which reduces the color fastness to rubbing.

\nPolyacrylic acid swells easily under wet conditions, which reduces the strength of the film and the color fastness to wet rubbing. <\/span><\/p>\n

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\n3) How to improve<\/span><\/section>\n
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Choose the right adhesive

\nUse appropriate softener

\nPay attention to the baking and color-fixing process<\/span><\/p>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n<\/section>\n

<\/div>\n

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Extended reading: https:\/\/www.china-fire-retardant.com\/post\/9375.html<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Most of the current color fastness test methods are based on simulation tests or comprehensive tests based on the environment and conditions of action, and the fastness grade is ev…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[46],"class_list":["post-9193","post","type-post","status-publish","format-standard","hentry","category-textile-fabric-news","tag-db"],"_links":{"self":[{"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=\/wp\/v2\/posts\/9193","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9193"}],"version-history":[{"count":0,"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=\/wp\/v2\/posts\/9193\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9193"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9193"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.textile-fabric.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9193"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}