Domestic first – 30D/72F light mesh size-free DTY (for 400T pongee) yarn technology sharing

ForewordRecently, The textile industry is still sluggish. In order to better meet market demand and further reduce costs, "Suzhou Ruizhen Fiber" recently developed 30/72 light mesh pulp-free D...


Recently, The textile industry is still sluggish. In order to better meet market demand and further reduce costs, “Suzhou Ruizhen Fiber” recently developed 30/72 light mesh pulp-free DTY. This product can be woven without sizing, and the fabric style after dyeing and finishing is no less than that of sizing weaving. It is mainly used in the warp and weft directions of 400T pongee. At present, it has been highly recognized after being used by customers. By using slit warping, the desizing process in the dyeing factory is eliminated, and the comprehensive cost per meter of cloth can be reduced by about 0.4 yuan.

For polyester DTY There are generally two types of water-jet looms: sizing weaving and sizing-free weaving.The difference lies in the lightness and weight of the yarn network points. Light mesh yarns need to be sized for weaving, and the warp network points are opened after dyeing, finishing and desizing. Sizing-free yarn needs to increase the network points to make the yarn cohesion better to achieve the purpose of sizing-free weaving. However, increasing the network points will cause ant spots to appear on the cloth surface and light transmission. The two are contradictory.

Now share the yarn craft as follows :



Raw material preparation

Polyester yarn: Tongkun Group Hengyou Factory Semi-gloss POY51dtex /72f. Its physical indicators are as follows: breaking strength 2.53cN/dtex, elongation at break 132.9%, thermal stress 63.8cN, oil content 0.32%.

Oil: JD-202GA special oil for ultra-fine denier polyester yarn produced by Jinerdi Lubricant (Zhejiang) Co., Ltd.



Equipment and process flow

Production equipment: Domestic Jinggong 1000V texturing machine, equipped with Inovance Technology online tension monitoring system, Suzhou Hongyi top roller, Holley twist stopper, French expanded PU disk (diameter 52.5, hardness 86 degrees), network device customized with 2.0mm aperture .

Test equipment: Changzhou Textile Instrument Factory Co., Ltd. YG086 yarn length measuring machine, Changzhou YG023B-11 fully automatic single yarn strength machine, German Schmidt handheld tension meter

Process flow: This product is produced on the Jinggong 1000V texturing machine. The production process flow is shown in Figure 1.

Polyester yarn → cutter → one roller → twist stopper → first hot box → cooling plate → false twister → warp tension → two rollers → network device → Second hot box → three rollers → probe → oiling → roll forming



texturing process

This test used imitation ultra-fine denier porous 51dtex/72f polyester POY filament is used as the main raw material. The main parameters of the texturing process are machine speed, draft ratio, upper hot box temperature, false twister D/Y ratio, lower hot box temperature, network pressure, etc. In order to choose appropriate parameters, we selected 13 zones and a total of 156 spindle positions on the 1000V texturing machine for trial production. We selected 5 different sets of process parameters. Each set of parameters produced 156 pieces of finished yarn. Different parameters have different effects on the finished yarn. The appearance and dyeing performance are shown in Table 1 below.

The sample shows: the machine processing speed is 600m/min, the draft ratio is 1.69, the upper The hot box temperature is 180°C, the lower hot box temperature is 160°C, the D/Y ratio is 1.55, the main network pressure is 0.15 MPa, the yarn outlet ratio is -6.5%, and the winding ratio is -5.5%. The finished yarn has the best appearance and dyeing performance.



Technical points

(1) Wool control

The monofilament of this product is 0.42DPF (30D÷72F=0.416). The control of wool is the difficulty in processing ultra-fine denier yarn. Here, we focus on introducing it.

First, the vehicle speed should not be too high. In order to maintain yarn quality, the texturing speed should be reduced as much as possible to reduce and prevent fiber breakage during the stretching and deformation process. The raw material status is 51 decitex, a 2.0mm aperture network device is selected, the network pressure is 0.15Mpa, and the number of network points per meter is 88.

The second is to use low-hardness PU disks. Due to the fineness of the fiber monofilament, if the PU disk is improperly selected, it is easy to wear and cause lint, incomplete untwisting, tight spots, etc. Even if the process is adjusted, the situation cannot be improved well. For this reason, we selected high-quality, low-hardness French expanded PU disks, with an assembly method of 1-5-1 and a D/Y ratio of 1.56. The PU disk is made of soft material and can be processed flexibly with little damage to the filament, allowing the filament to obtain a more complete and stable structure and improve its strength. At the same time, when producing ultra-fine denier yarn, it can reduce the finished fiber and improve the dyeing uniformity. It can also lay the foundation for increasing the subsequent processing speed and improve customer satisfaction.

The third is to use high-quality twist stoppers. During the stretching and deformation process of the yarn, the functions of the twist stopper: 1. Act as a pulley when the silk path changes direction at a small angle; 2. The angle of the twist stopper allows the twist of the yarn to be retained in the hot box for deformation As well as shaping, the twist is not transmitted in the direction of one roller. Therefore, if the twist stopper is improperly selected, it can easily damage the fiber and cause filament. After many comparisons, we finally selected the Holley twist stopper, which has relatively stable production and no lint.

(2) Selection of network nozzle and pressure

The function of the network nozzle is to stretch and deform the polyester yarn in It is bundled before entering the second hot box for shaping to facilitate subsequent weaving. For this reason, the selection of network nozzles and the selection of network pressure are crucial. During the trial production phase of this product, we selected network nozzles with different hole shapes and diameters, and used different pressures for sample comparison. The test results are shown in Table 2 below:

From the test parameters and results, the A2.0 network device and the network pressure of 0.15Mpa are the best, and the customer recognition is high. Other conclusions are also drawn from the test: Network The smaller the aperture, the more network points, and vice versa

(3) Selection of oil agent

On the one hand , when the yarn is nearly 3 kg fully wound, the winding tension is low at this time. If the oil agent is selected appropriately, the yarn will jump in the yarn detector, causing the yarn detector to misjudge the wire cutting, resulting in unnecessary Beheaded.

On the other hand, when oiling the tow, attention must be paid to the oiling rate and the control of the oiling rate uniformity between spindle positions. In terms of oiling rate, The speed of the tanker and the level of the oil level play a decisive role, but we cannot simply think that the speed of the tanker is directly proportional to the amount of oil. We must also pay attention to the influence of the kinematic viscosity of the oil, ambient temperature, winding tension, etc. These factors All will affect the oiling rate and uniformity. After many comparisons, we finally selected the JD-202GA type special oil for ultra-fine denier polyester yarn, and the feedback on the finished product was good.



Finished product physical performance indicators

When the speed of the 312-ingot texturing machine is 600 meters/minute, the daily output is 0.88 tons, the finished product has a fixed weight of 3 kilograms, and the excellent rate is 92%.

The physical indicators are as follows: breaking strength 4.02cN/tex, elongation at break 21.3%, oil content 2%.

Weaving conditions: speed 600-680 rpm, efficiency 98-99%.

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