FZ/T 50015-2009Test and assessment for dyeing uniformity of viscose filament yarn (English PDF)

3.1 Yarn irregularity

After the weft-knitted fabric is dyed, the uneven thickness of yarns in the loop results in uneven thickness of the warp loops or uneven density between the sets.

3.2 Color strip

Chromatic yarn

Zebra yarn

After weft-knitting dyeing, the thickness of the filaments in the knitted fabric loops is uniform, but there is a section or more of color difference between the

-- Dye solution (0.08 g/L);

-- Liquor ratio: 1:100 (reduce the liquor ratio appropriately for rope and jet dyeing; control the liquor ratio at 1:20 ~ 1:100; remain the concentration of the dye solution unchanged).

Note: add the reagents in the dye liquor in the order of sodium carbonate- sodium sulfate-dye; prepare in time during dyeing.

6.8 Centrifuge: household dehydration machine or other centrifugal dehydration

device.

6.9 Tension meter (0 cN ~ 350 cN).

6.10 General laboratory equipment, special markers.

7.1 Sampling

-- According to the number of spinning machines and the doffing time, the manufacturing plant randomly and uniformly selects a certain number of packages from each doffing package; the number of the selected dyeing performance samples shall be determined by each manufacturing plant;

-- Take out laboratory samples of loose parts as needed;

-- The sampling of laboratory samples in batch samples shall be in accordance with GB/T 6502.

7.5.1 Conditions and observations

Use the D65 standard light source to illuminate above the working point, with gray surroundings and no scattered light around. Use an illuminance meter to test that the illuminance of the working point is greater than or equal to 600 lx.

The incident light is at an angle of 45° with the sample surface; the direction of eye observation is roughly perpendicular to the sample surface.

Smoothly unfold the sample garter; place it on top of the gray card; move it slowly to observe the sample section by section. Use the frame compression frame that is provided by GB/T 250 to press the deepest and shallowest sample;

access it visually according to the gray scale.

Compare the dark and light spots, stripes, bands and patterns in the same garter belt with the surroundings; evaluate it visually according to the gray scale.

7.5.2 Evaluation rules

7.5.2.1 The sample shall be uniformly colored and free of variegation that is caused by the dyeing process, before it can participate in the dyeing uniformity assessment. When uneven dye is found, weave and dye again.

7.5.2.2 For the range of the dyed sample (including the depth strips in the same section of the garter), the gray scale shall be assessed according to the GB/T

250 comparison.

7.5.2.3 Blue uneven dyes, stripes, bands, patterns: set it as a qualified product

when there are two or less samples; set it as a non-standard product when there are three or more samples. Shallow uneven dyes, stripes, bands, patterns:

set it as a qualified product when there is one sample; set it as a non-standard product when there are two or more.

When shallow color strips cause the sample to break, it is deemed as a non- standard product.

7.5.2.4 When there is yarn irregularity, set the sample of the uniform thin filament segment as qualified product.