1
What is silk network degree
The product of network processing is called network wire, also known as interlaced wire. It uses compressed air flow to spray, impact and collide the filament bundles, so that Irregular intersections occur between individual filaments in the filament bundle, forming knotted filaments with good cohesion properties.
If pre-oriented yarn (POY) is processed through the network, it can increase the cohesion between POY monofilaments, improve its post-processing performance, and make it have better Excellent unwinding performance, it is not easy to produce filaments, broken ends and loose loops during stretching and deformation.
When the drawn yarn and textured yarn are processed through the network, the processes of doubling, twisting, and sizing can be omitted in the weaving process, and the yarn can be directly processed. The network yarn is woven on the machine, and can reduce the breakage rate and increase labor productivity by 10% to 20%. The fabric has a certain wooly feel, is not easy to pill, and does not have the brightness of synthetic filament.
2
How to measure network degree
The “needle construction method” is often used to measure network degree, which is the simplest method. He uses small needles to insert into the network filaments for combing, thereby measuring the distance and distribution between network points of the network filaments. The measuring device is shown in Figure 14-5.
When measuring, first insert the winding bobbin of the network filament into the bobbin holder of the measuring instrument, and pull one end of the wire with your hand to withdraw from the bobbin. Wire, pass through the guide wheel, take a 1m sample, clamp it with a chuck, and hang a weight equivalent to 1/10 of the fiber fineness vertically from the lower end of the wire (if measuring 167dtex filament, hang a 16·7cN weight code), and then use a 4g thin steel needle to insert into the upper end of the silk strip, so that the silk strip is roughly divided into 2 bundles.
Hang a weight equivalent to 1/5 of the fineness at each end of the thin steel needle, so that the steel needle falls at a speed of 2cm/s. Write down The distance the needle falls. Repeat the above test 50 to 100 times, find the average distance X of the steel needle falling 50 times or 100 times, and take its reciprocal to get the network degree.
3
Internet silk Network degree
The network stability (network elimination rate, %) is measured by adding the lower end of the network filament measured by the network degree above. Static load of 2.2cN/dtex, leave it for 1 minute, remove the load, measure the network degree, and take the average of five times. Calculate the network cancellation rate according to the following formula:
Network cancellation rate (%) = (1-G/E) × 100
In the formula: E——not added Network degree before load; G——Network degree after adding 2.2cN/dtex load.
4
Internet silk loops Stable
(1) Winding wire twist:On a winch with a frame circumference of 1m, use 0.01 The pre-tension of cN/dtex is used to wind the silk skein so that the total fiber fineness is 2500dtex.
For example, when skeining a 167dtex filament, the number of turns is calculated according to formula (11-7).
The number of turns of the silk strand = the total fineness of the silk strand (dtex)/the fineness of the silk sliver (dtex)*2=2500/(167*2)=7.
(2) Measure the length a of the wire twist:The wire twist is maintained for lmin under a load of 25cN (0.01cN/dtex), and measure a. The load value is calculated based on the total fineness of the undeformed raw silk strand, which is 0.5cN/dtex.
(3) Measure the length b of the wire twist: Maintain the wire twist under a load of 1250cN for 1 min, and measure b. The load value is calculated based on the fineness of the undeformed raw silk strand, which is 0.5cN/dtex.
(4) Calculate the loop instability I1:I1(%)=(b-a)/a*100.
(5) Measure the length c of the strand:After measuring the length b of the strand, relax it for lmin, and then add a load of 25cN (0.0lcN/dtex). The load value is as follows Calculate the fineness of the undeformed raw silk skein. After lmin, measure the length c of the skein.
(6) Calculate the instability I2 of the wire loop: I2 (%) = c-a/a*100.
5
Boiling water for air textured yarn Shrinkage
(1) Winding wire twist: The wire is wound under a pre-tension of 0.018cN/dtex Knit, each circle is 1m, 8 circles in total.
(2) Measure the length of the strand a:The load of the dry strand is the value of the total fineness of the undeformed original strand plus 0.018cN/dtex, Measure the length a after 1 minute.
(3) Shrinking treatment:Shrink the strands in 95°C distilled water containing 1g/L Erkamtol Ba-Bager, an anionic active agent, for 15 minutes in a tension-free state. .
(4) Drying:Use a cloth or paper towel to absorb the water attached to the skein, and then dry at 50°C for 30 minutes.
(5) Measure the length of the skein b: The load of the skein is taken as the value of the total fineness of the skein of the undeformed raw silk.0.018cN/dtex, and measure the length b after 1 minute.
(6) Calculate the shrinkage rate of boiling water:Shrinkage rate of boiling water (%) = a-b/b *100.
6
Air textured wire loop Height and density
The effect of deformation of air-textured yarn and its post-processing weaving performance and fabric feel, style, loop height and mesh density Therefore, this is an extremely important indicator of air deformation yarn.
(1) Measurement of wire loop height:Because the wire mesh size is different, the distribution is uneven, and the discreteness is large, so it is generally expressed by statistical values. The definition of DuPont in the United States is as follows:
Wire loop height = (maximum wire loop outer diameter – wire body diameter)/2
In actual measurement, since the probability of the wire loops being distributed along the surface of the wire strip is equal, the size of the wire loops can be known as long as the projection height of one side is measured with a projector. In this way, the testing efficiency can be doubled and the error can be reduced by half.
(2) Determination of loop density:The loop height of air textured yarn is low and the density is high. At present, the domestic hairiness meter is used to measure, but the resolution does not meet the requirements, so the error is large. Visual inspection with a projector can also be used. This is a method of measuring the number of single-side screen projections of air-textured yarns and then calculating them.
7
A network of air-textured wires Degree
Network is a main feature of the air deformation silk body, and the number of network points reflects the network effect.
Since the aggregation density, cohesion force, diameter, etc. of fibers in network points are different from those in non-nodes, the degree of network affects the bending stiffness and density of air deformed yarns. , bulkiness, evenness and dyeing uniformity all have a certain impact, so the determination of its network degree is very important.
Due to the high network density of air-textured wires (more than 3 to 5 times higher than network wires), and the length of network points cannot be ignored, the network of air-textured wires The degree is expressed by measuring the number of complete network points per meter of wire, and then taking the average to express it, rather than dividing the distance between nodes by a fixed length like network wire to obtain the network degree.
8
Diameter of air-textured wire
The diameter of the thread is an important parameter in the design of fabric structure. It is related to the thickness, stiffness, feel, etc. of the fabric. Photoelectric scanning method is used to measure diameter abroad. Since there is no such instrument in China, a projector is used to measure the diameter. However, since the cross-section of the air-deformed wire is approximately elliptical, a synchronous rotator can be added to the projector, so that the projection length of the major and minor axes of the ellipse can be measured, and then its equivalent diameter D can be calculated.
D=√ab
Where a and b are the projection lengths of the long and short axes respectively.
9
Dynamic instability
The stress experienced by the yarn during the weaving process or direct use changes within a certain range. Under this dynamic load, the yarn The strip structure will undergo significant changes resulting in irreversible deformation.
A simple device can be designed to push the crossbeam to reciprocate up and down through the rotation of the cam, thereby measuring the elongation change rate of the wire under dynamic load, expressed in this way Dynamic instability of deformed yarn S.
S(%)=（L2-L1）/L1 *100
In the formula ：L1——Initial length; L2——Length after adding dynamic load
