Sewing Thread only makes up a small percent of the cost of the sewn product, but shares 50% of the responsibility of the seam. The good color fastness of the thread makes it resistant to the various chemical and physical agents the thread is exposed to during manufacturing and during its useful life, especially during washing, perspiration, sublimation, etc. This ensures no bleeding of the color into the garment. Also, it should be dyed evenly and uniformly.
Table of Contents
Dyeing of three types of sewing thread
After the sewing thread yarn is manufactured, it is wound on dye tubes so it can proceed to one of the dye houses for dyeing.
Different fiber types are dyed with different dye types and temperatures to achieve the desired shade and color fastness requirements.
- Polyester threads- Normally dyed with Disperse Dyes at high temperatures (265° F / 129° C) using high energy dyes to ensure good colorfastness.
- Nylon threads- Normally dyed with Acid or Chromatic dyes to achieve the desired shade.
- Natural fibers including cotton and rayon- Can be dyed with either Vat, Fiber Reactive, or Direct dyes depending on the color fastness requirements and the color shade to be achieved. Generally, Vat-dyed natural fibers have the best color fastness characteristics.
Why industrial sewing thread should conduct colorfastness testing
Colorfastness is the resistance of a fabric to change in its color characteristics or to transfer its colorant(s) to adjacent materials. Colorfastness issues can be caused by:
Fiber type: Fibers must be compatible with their chosen dye. A cellulosic fiber and a vat dye together have good resistance to fading, for instance, while polyesters perform well with substantive dyes.
Dye type: The larger the dye molecule is, the easier it will attach to the fiber. Some dyes are also water-soluble, while others are insoluble.
Poor color fastness can cause fabric shade variation or color fastness test the staining of other products. Any number of activities associated with regular use can reveal these issues, including:
- Sun exposure
- Dry cleaning
Read More: The Best Polyester Thread for Sewing Machine
Five types of colorfastness testing of industrial sewing thread
Colorfastness during washing
Colorfastness during washing is one of sewn product manufacturers’ main concerns. An industrial sewing thread item must withstand repeated washing throughout its lifecycle without losing its color properties or staining sewn product it’s washed with.
Detergent washing testing determines the resistance of industrial sewing thread colors to domestic or commercial laundering procedures. The two main standards for detergent washing are ISO 105 C06 and AATCC 61.
Aim for a color change rating of 4 and a color staining rating of 3 to 5 for detergent washing.
Colorfastness to Crocking(wet and dry rubbing)
“Crocking” is an industry term referring to a transfer of a colorant through rubbing. The crocking test determines the resistance of industrial sewing thread colors to rubbing off and staining other materials. An industrial sewing thread with poor color fastness could rub colorants off on consumers, furniture, other textiles, or miscellaneous items.
ISO 105 X12 and AATCC 8 are the primary standards for measuring color fastness to crocking. The standards are partly equivalent and largely similar in their test methods.
Colorfastness to light
Colorfastness to light is a measure of how permanent color is on fabric after exposure to light. Both natural and synthetic fabrics of industrial sewing thread are subject to discoloration under UV rays (sunlight) and fluorescent light, as colorants by nature absorb certain wavelengths. But sewn product manufacturers don’t want the colored fabric and industrial sewing thread to fade too quickly over the course of its life.
Colorfastness to light testing might be particularly important to importers of clothing worn predominately outdoors. But even retail display lighting can cause fading.
ISO 105 B02 and AATCC 16 are the most common international standards for color fastness to light. Both standards test fabrics under a Xenon Arc lamp that closely resembles natural sunlight. But the standards vary significantly in their assessment methods.
Colorfastness to perspiration
The color fastness to perspiration test determines the resistance of industrial sewing thread colors to human perspiration.
Fabric dyes and human perspiration can often react and cause color fading in industrial sewing thread. A color fastness test for perspiration is particularly relevant for industrial sewing thread OFsports apparel and swimwear, which will most likely be exposed to heavy perspiration during use.
ISO 105 E04 and AATCC 15 are the two main standards for perspiration testing. For this test, the lab attaches a strip of industrial sewing thread to the test specimen to measure staining.
The lab then compares the staining of the industrial sewing thread to the Grey Scale for Staining, with a desired grade 3 rating. The lab compares the color of the test specimen with the Grey Scale for Color Change, with a desired grade 4 rating.
Colorfastness to water
Colorfastness to water determines the resistance of industrial sewing thread colors to immersion in water.
You might think this test sounds like the washing test. But color fastness to water testing is specifically used to measure the migration of color to another fabric when wet and in close contact. The washing test also typically uses a basic PH solution due to the addition of detergent, while this test is conducted at neutral PH levels.
ISO 105 E01 and AATCC 107 are the most common standards for color fastness tests to water. The standards are technically equivalent, but the testing methods vary slightly between them.
Some color fastness tests might be more important to you than others, depending on the design and intended use of your industrial sewing thread of textile products. Other standards also exist for color fastness to sea water, chlorinated water, hot pressing, and other unique conditions.
Colorfastness issues aren’t usually noticeable until after the sale. But industrial sewing thread fading and staining can cause serious headaches for your business when customers later discover these issues.