The dyeing and finishing process of recycled polyester knitted fabrics is introduced. It is pointed out that the performance of recycled polyester itself has a certain impact on the dyeing effect, so each batch of recycled polyester needs to be re-sampled before dyeing; the temperature rise curve of recycled polyester knitted fabrics should be designed slower, with a dyeing temperature of 125°C, a dyeing time of 20 minutes, and a dyeing pH value of 4.0 ~ 5.0; when restoring and cleaning, the pH value should be controlled not to exceed 11.0; the color fastness to washing, acid perspiration and light of the recycled polyester dyed in this way is comparable to that of ordinary polyester, and can reach level 4 or above. .
In addition, it is pointed out that the oil content of recycled polyester is higher than that of ordinary polyester. In the pre-treatment stage, pre-treatment additives should be preferred, the amount of degreasing agent should be increased, and the pre-treatment temperature should be increased; for regeneration Polyester knitted fleece fabrics should be padded with antistatic agents before fleecing, and the production processes and process parameters between fleecing, carding, and shearing should be reasonably designed to achieve a good fleece effect.
Recycled polyester
The so-called recycled polyester is the use of complete cycle chemical recycling technology. Wasted polyester fabrics, clothing or polyester waste are recycled centrally, crushed into granules, then decomposed into polyester raw materials through chemical treatment, and finally spun into polyester. According to statistics, 1.00t of waste polyester bottles can be used to produce about 0.98t of recycled polyester, saving 6.00t of oil and 3m3 of landfill space. For this reason, the recycling of waste plastics and the production and use of recycled polyester are inevitable choices for developing a circular economy and building a resource-saving society.
Compared with ordinary polyester, recycled polyester has better hygroscopicity and air permeability, and can be widely used in the production of sportswear. However, recycled polyester has a high oil content, high rigidity, and is not as strong and heat-resistant as ordinary polyester. Each batch of recycled polyester produced by the manufacturer has certain differences in performance and color, which increases the difficulty of subsequent processing.
At present, there are many studies on the spinning and weaving of recycled polyester. This article discusses the dyeing and finishing process of recycled polyester knitted fabrics.
1 Test
1.1 Fabric
Recycled polyester knitted fabric: instrumented with 22.22tex(200D)/100f Yuhui recycled FDY polyester filament is terry yarn, and 8.33tex (75D)/36fDTY polyester low elastic yarn is terry yarn connecting yarn.
Ordinary polyester knitted fabrics: towels using 22.22tex (200D)/100f Yihua Yuhui FDY polyester filament as terry yarn and 8.33tex (75D)/36fDTY polyester low elastic yarn as connecting yarn. cloth.
1.2 Reagents and instruments
Reagents: disperse dye RubineS-2GFL [Clais Chemical Group (China)], high temperature leveling agent 3620 (Shanghai Hansong Textile Technology Co., Ltd.), acetic acid (industrial grade), sodium acetate (industrial grade), chelating dispersant YH-56 (Shanghai Yihua Industrial Chemicals Co., Ltd.), etc.
Instruments: Datacolor650 color measuring and matching instrument (Datacolor Company of the United States), Burst Tester (Mullen RTesters Company of the United States), Washing Color Fastness Testing Machine (James H.heal&Co.Ltd.HalifaxEngland), Light Fastness Testing machine (James H.heal Co., Ltd., UK), perspiration color fastness oven (Nantong Hongda Company), etc.
1.3 Dyeing process prescription and curve
1.3.1 Process prescription
RubineS-2GFLl%
HAC0.8g/L
Warm leveling agent 36200.8g/L
NaAcl.0g/L
Chelating dispersant YH-560.3g/L
1.3.2 Process curve (omitted)
1.4 Test method
1.4.1 Test of color difference
Use Datacolor650 color measurement and matching instrument to test the color difference △Ecmc of different batches of fabrics after dyeing.
1.4.2 Test of relative dye uptake rate Relative dye uptake rate-A/B×1000/(1) In the formula: A is the K/S value dyed under certain conditions; B It is the K/S value of the fabric dyed at 135°C and 30 minutes. The K/S value is measured by Datacolor650 color measurement and matching instrument.
1.4.3 The test force score is directly measured and read out by the Datacolor650 color measurement and matching instrument. The meaning of its value is the percentage of staining depth of the test sample and the standard sample. The dyeing sample of recycled polyester fabric at 125°C and 30 minutes was used as the standard sample.
1.4.4 Test of bursting strength retention rate
The bursting strength test is in accordance with the American Society for Testing and Materials standard ASTM D3786-2001 “Standard for hydraulic bursting strength of fabrics
>Testing methods are carried out according to the provisions of the Film Burst Strength Tester Act. The calculation of the strength retention rate P is as shown in formula (2): P-(Po-Pl)/PO×100% (2) where: Po is the bursting strength of the fabric before treatment; Pl is the bursting strength of the fabric after treatment Strong.
1.4.5 Testing of color fastness to washing Color fastness to washing shall be carried out in accordance with the provisions of IS0105C06-2010 “Tests on color fastness of textiles – Part C06: Color fastness to household and commercial washing” test.
1.4.6 The color fastness to acid and perspiration is tested in accordance with the test of color fastness to acid and perspiration in IS0105E04-2009 “Textiles Color Fastness Test Part E04: Color Fastness to Perspiration”. Fastness requirements are tested.
1.4.7 Test of color fastness to light The color fastness to light test is in accordance with IS0105802-1994 “Textiles Color Fastness Test Part B02: Color Fastness to Artificial Light: Xenon The test shall be carried out according to the requirements of Arc Lamp Test.
1.4.8 Color fastness rating The color fastness rating is in accordance with IS0105A02-1993 “Textiles Color Fastness Test Part A02: Gray Sample Card for Evaluating Discoloration” and IS0105A03- 1993 “Textiles Color Fastness Test Part A03: Gray Sample Card for Evaluating Staining” were conducted separately.
2 Results and Discussion
2.1 The influence of the properties of recycled polyester itself on the dyeing effect. Due to the relatively complex production process of recycled polyester fiber, Long and diverse raw materials, so it is produced�Heat setting process. The specific control methods are shown in Table 6.
3.3 The napping, carding and shearing process of recycled polyester knitted fabrics
Before napping of recycled polyester knitted fabrics
Table 6 Comparison of heat-setting surface temperatures of recycled polyester and ordinary polyester fabrics
The preferred antistatic agent for pad rolling , reduce lint, control the fabric feeding tension, the speed of straight needles and curved needles during the napping process, and optimize the knife distance, brush distance, speed and other process parameters during the shearing process. For example, in the napping process, ordinary polyester knitted fabrics straight needles and curved needles The needle speed difference is 15r/min, while the difference between the straight needle and the curved needle speed of recycled polyester knitted fabric is 19r/min, which can ensure that the tension of the recycled polyester fabric is small during the napping process, which can effectively solve the problem of napping of recycled polyester knitted velvet fabrics. It is easy to remove hair during the process and achieve a good suede effect.
4 Conclusion
4.1 The properties of recycled polyester knitted fabrics have a certain impact on the dyeing effect. The performance of recycled polyester is unstable, and each batch of recycled polyester needs to be re-sampled before dyeing.
4.2 The temperature rise curve of regenerated polyester knitted fabrics should be designed to be slower, with a dyeing temperature of 125°C, a dyeing time of 20 minutes, and a dyeing pH value of 4.0 to 5.0; when regenerating polyester knitted fabrics are restored and cleaned, the pH should be controlled as much as possible. The value cannot exceed 11.0.
4.3 For recycled polyester, attention should be paid to the adjustment and control of process conditions during the pre-treatment, shaping and napping stages. </p
