This standard specifies the determination methods of the linear density of packaged yarn below 2000tex, including seven methods. This standard is applicable to all types of yarn. GB/T 4743-1995 Determination of linear density of yarn - skein method GB/T4743-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of linear density of yarn by the skein method
Textiles-Yarn from packages-DeterminationOf linear density(mass per unit length)bytheskeinmethodGB/T4743--1995
Replaces GB4743-84
This standard adopts the international standard IS02060.2-1993 "Textiles--Yarn from packages-Determination of linear density (mass per unit length) by the skein method" 1 Subject content and scope of application
This standard specifies the determination methods of linear density of yarn from packages below 2000tex, including seven methods. This standard is applicable to all kinds of yarns.
2 Reference standards
GB2910 Quantitative chemical analysis method for three-component fiber blends GB2911 Quantitative chemical analysis method for three-component fiber blends GB6529 Standard atmosphere for humidification and testing of textiles GB9995 Determination of moisture content and moisture regain of textile materials - Oven method FZ/T01026 Quantitative chemical analysis method for four-component fiber blends FZ/T01035 General system for indicating linear density of textile materials (tex system) 3 Terms
3.1 Commercial moisture regain When calculating linear density or commercial mass, an agreed value used together with the drying mass of the textile material is officially adopted as moisture regain. 3.2 Commercial allowance When calculating linear density or commercial mass, an agreed value used in conjunction with the drying mass of textile materials is equal to the sum of commercial regain and the approved allowance for the finishing agent.
4 Principle
Linear density is the mass of yarn per unit length. Therefore, the mass of a fixed length of yarn is weighed under certain conditions and the linear density can be obtained by calculation. 5 Instruments
5.1 Yarn length measuring device
The circumference of the yarn should be sufficient to obtain the required yarn length by the number of full turns. The recommended circumference is 1000±0.5mm. It has a traverse guide device to avoid yarn accumulation. It is equipped with an active feeding system for quantitative tension control: or by other methods [see Appendix A (Supplement)) to enable its tension to be quantitatively controlled. 5.2 Oven
The temperature can be maintained at 105±3℃: the sample is not exposed to direct heat radiation. The ventilation rate is at least once every 4 minutes, and the air can pass freely through the sample. It should also have a device to shut off the air flow and a weighing device in the sample box. The air supplied to the oven shall be any temperature and humidity agreed upon by both parties. 5.3 Balance
Sensitivity shall be one thousandth of the weight of the hank to be weighed 5.4 Auxiliary equipment
Sample rack, corrosion-resistant metal wire mesh weighing basket marked with empty weight, etc. 5.5 Cleaning or extraction equipment, if necessary, equipped with C (see Appendix B (Supplement)). 6 Standard atmosphere
Prehumidification, humidity conditioning and standard atmosphere for test shall be in accordance with the provisions of GB6529. 7 Sampling
In accordance with the provisions of relevant product standards.
8 Test steps
8.1 Prehumidification and humidity conditioning
Prehumidify the sample for at least 4 hours, then expose it to the standard atmosphere for test for 24 hours, or expose it for at least 30 minutes, and the mass change shall not exceed 0.1% 8.2 Shake the test hank
Shake the hank according to the specified sample length and winding tension, and the knot shall be shorter than 1 cm. If the length of the skein needs to be checked, the yarn frame arm should be retracted and the yarn removed.
8.2.1 Skein length
When the linear density is less than 12.5tex: 200m: a.
b.When the linear density is between 12.5 and 100rex: 100mc.When the linear density is greater than 100tex: 10m. 8.2.2 Yarn tension
For non-deformed yarn and bulked yarn: 0.5±0.1cN/tex; for knitted velvet and woolen yarn: 0.25±0.05cN/rex; for other deformed yarns: 1.0±0.2cN/tex. 8.2.3 Number of samples
As specified in the relevant product standards. In the absence of such standards, it should be determined by mathematical statistics based on the precision and probability level required for the test results. At least 4 packages of filament yarns shall be tested, and at least 10 packages of staple yarns shall be tested. At least 1 skein of yarn shall be taken from each package. If the coefficient of variation of linear density is to be calculated, at least 20 samples shall be tested. 8.3 Weighing
8.3.1 Method 1: Measurement of linear density of conditioned yarn Directly weigh the mass of the conditioned test skein. 8.3.2 Method 2: Measurement of linear density of dried yarn Dry the test skein at 105±3°C to constant weight, i.e., continue drying until the mass change is not significant within a time interval of 20 minutes: 0.1%. When weighing, the air flow and electric heating must be turned off, and weighing should be started after 1 minute and completed within 10 minutes. 8.3.3 Method 3: Measurement of linear density of yarn with commercial regain The steps are the same as those of Method 2. 8.3.4 Method 4: Measurement of linear density of washed yarn after conditioning Wash the skein according to Appendix B, dry it, pre-condition it, condition it, and weigh it. 8.3.5 Method 5: Measurement of linear density of washed yarn after drying. Wash and dry the skein according to Appendix B, and then operate according to Method 2. 8.3.6 Method 6: Measurement of linear density of washed yarn with commercial regain. The steps are the same as those in Method 5.
8.3.7 Method 7: Measurement of linear density of washed yarn with commercial allowable ...
9Calculation
Linear density (tex unit) = hank mass (g) × (1 + R or K) × 1000 / hank length (m) Note: For details of tex units, please refer to FZ/T01035, including millitex (mtex), decitex (dtex), tex (tex), and kilotex (ktex). In the formula, R and K are the commercial regain and commercial allowance of the yarn, respectively. For blended yarns, R and K are calculated by weighting the commercial regain and content ratio of the fibers contained (measured in dry weight). This ratio is known or determined by GB2910 or GB2911 or FZ/T01026. When calculating the linear density, the corresponding hank mass is substituted according to the selected method. When it is required to correct the mass of the dried hank measured under non-standard atmospheric conditions, When correct, proceed according to Appendix A of GB9995. For methods 1, 2, 4, and 5, R and K are both equal to zero. The calculated linear density is retained to three significant figures. The coefficient of variation is retained to one decimal place. 10 Test report
Should state that the test is carried out in accordance with this standard and should include the following: a.
Average linear density expressed in Tex system
Number of specimens:
Length of each skein of yarn;
Coefficient of variation of linear density (if measured): The procedure selected, the specified commercial regain or commercial allowance (if applicable): The sampling plan used;
Standard atmosphere used for the test:
Ambient temperature and humidity of the oven:
Any details that deviate from this standard.
Additional notes:
This standard is proposed by the China National Textile and Apparel Council.
This standard is under the jurisdiction of the Standardization Institute of the China National Textile and Apparel Council. This standard was drafted by the Standardization Institute of the China National Textile and Apparel Council. The main drafters of this standard are Wei Hong, Wang Jun and Shen Liping. A1 Instrument
Appendix A
Method for verifying the length of the skeined yarn Yarn loop length meter method (supplement)Www.bzxZ.net
The yarn loop length meter is an instrument for testing the length of the yarn loop under certain load conditions. It consists of two round metal pegs with a diameter of about 1.25 cm and a length of 5 to 6 cm, which are in the same vertical plane. One of them is fixed to the frame of the instrument, and the other is mounted on a lever of a simple load-adding system. The fulcrum of the lever is a low-friction rolling bearing, which is also mounted on the frame. At least one of the two pegs should be able to rotate freely around the axis. There is a finger at the end of the lever. The markings are marked and a scale is mounted on the frame to indicate the ratio of the actual loop length of the hank to the circumference of the yarn frame (r). A2 Procedure
Hang the hank on two pegs to avoid bunching. Apply a tension (cN) equal to 2X the number of hank turns X nominal linear density (tex) X specified winding tension (cN/tex) and read the r value.
A3 Requirements
When r exceeds the limit of ±0.2%, the yarn length measuring device winding tension should be adjusted. B1 Principle
Appendix B
Method for cleaning yarn to remove finishing materials
(Supplement)
The hank should be scoured under conditions that remove all oils, finishing agents or other substances that are normally removed during the wet processing of fabrics made from such yarns. This condition is considered to have been met when the yarn is extracted with one or more suitable finishing agents that have no swelling effect on the fibers being tested and show less than 0.1% residual finishing agent. B2 Reagents and Equipment The following reagents and equipment are required for the scouring test of skeins: B2.1 Neutral soap flakes or detergent.
B2.2 Soft, distilled or demineralized water. B2.3 A water pan made of a corrosion-resistant material such as monel, aluminium, stainless steel or porcelain, heated by a closed steam coil or jacket, or by gas or electricity, fitted with drainage and a soft water supply, and designed to be flushed by overflow. NOTE: A domestic automatic washing machine or a small corrosion-resistant container such as a glass or stainless steel beaker may be substituted for the water pan specified above. B2.4 A roller mangle or centrifugal dehydrator. B2.5 Bags made of desized and bleached nylon, polyester fabric or other material, which have been previously scoured and have a known dry weight. The size of each bag should be large enough to allow the test hank to form a porous, loose mass and to allow the scouring solution to flow freely into and out of the hank.
B2.6 Oven (see 1.2).
B2.7 Balance (see 5.3).
B3 Procedure
Place the hank in a bag (B2.5) of known dry weight. Immerse each bag containing the hank in a water pan (B2.3). The pan must contain at least 25 ml of water per gram of hank to be scoured, and each litre of water must contain 0.5 g of neutral soap or an equivalent amount of other detergent (B2.1). The pan is kept boiling and agitated for 30 min. After scouring, rinse with soft water (B2.2) at 75 ± 3 ° C until all surface scum is removed. If boiling is known to be harmful to the fibers under test, the temperature of the washing liquid shall be agreed upon by the parties concerned. Drain the excess liquid, squeeze dry, and then rinse thoroughly with soft water at 75 ° C for 10 min with stirring. Repeat squeezing and rinsing with soft water at 75 ° C for 10 min with stirring. Repeat squeezing and rinsing with soft water at room temperature for 10 min with stirring. Squeeze the hank a final time. B4 Verification of the effect of scouring
The effect of scouring can be verified by extracting some of the scourged and dried yarn with a solvent in which the fibres being tested are insoluble. If the amount of extractable matter obtained exceeds 0.1%, the scouring must be improved by using more or better detergent, higher temperature, more vigorous stirring, longer time or a second scouring. NOTE: When it is shown that the results obtained by extraction alone are the same as those obtained by the reliable scouring procedure or that there is a constant ratio between the two, extraction can be used for routine testing of known products, but extraction should not be used instead of scouring for new or unknown materials.
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