Three-proofing finishing process for polyester / spandex knitted fabric

Abstract

The invention belongs to the technical field of textile, and discloses a three-proofing finishing process for polyester / spandex knitted fabric, which comprises the steps of fine pretreatment, three-proofing finishing agent padding, sectional drying, tension control sizing and post-treatment curing. Low-temperature enzymolysis and environment-friendly surfactant synergistic pretreatment are carried out, so that the cleanliness of the fabric is improved; a finishing agent compounded by a fluorine-containing copolymer, a cross-linking agent and a penetrating agent is adopted, and the adhesion stability is enhanced by combining a two-dipping and two-rolling process; the thermal damage of the spandex is reduced through sectional drying and tension setting; carrying out post-treatment curing to promote cross-linking and remove the free finishing agent. The water resistance, oil repellency, decontamination performance and washability of the polyester-spandex knitted fabric are remarkably improved, meanwhile, the elasticity and breathability of the fabric are kept, the process is controllable, and the method is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of textiles, specifically a three-proofing finishing process for polyester-nylon knitted fabric. BACKGROUND

[0002] Polyester-nylon knitted fabric occupies an important position in the textile field due to its unique performance advantages. It skillfully combines the high-strength characteristics of polyester fibers with the high-elasticity characteristics of spandex, and this perfect combination makes it shine in many application scenarios and is widely and massively used in sports clothing, outdoor equipment, and home textiles. Whether it is the toughness and durability required during exercise or the pursuit of comfort and elasticity in daily wear, polyester-nylon knitted fabric can meet the needs well. However, during actual use, this type of fabric also exposes some disturbing problems. Its surface is prone to adsorbing oil stains, just like a magnet naturally attracts iron filings, oil stains will quickly adhere to the surface of the fabric; at the same time, it is also easy to stain various stains, and once stained, it is difficult to remove easily. In order to improve this situation, the traditional three-proofing finishing process has emerged, but this process has many defects that cannot be ignored: Firstly, in the pretreatment link, high-temperature strong alkali cleaning method is often used. This method is like a double-edged sword. On the one hand, the high-temperature strong alkali environment is extremely detrimental to spandex, and it can easily accelerate the aging process of spandex, just like excessive exposure to sunlight can make rubber products become fragile and brittle, and the elasticity and other properties of spandex will gradually decline under the action of high-temperature strong alkali; on the other hand, this cleaning method also has the problem of incomplete cleaning, and if it is not cleaned thoroughly, the subsequent finishing agent will not adhere uniformly, thereby affecting the stability of the three-proofing effect and failing to achieve the expected long-lasting protection effect.

[0003] Secondly, the bonding force between the finishing agent and the fiber is very weak. This is like the adhesion between two objects is not enough, and it is easy to separate under the action of external force. In actual use, the fabric treated by this finishing process has poor washability. Usually, after 5-10 washes, the three-proofing performance of the fabric will decrease significantly, and the original waterproof, oil-proof, and stain-proof effects will be greatly reduced, and the fabric cannot continue to provide effective protection.

[0004] Thirdly, in the drying and setting process, a single high-temperature treatment method is often used. This high-temperature environment is undoubtedly a severe test for spandex. It can easily cause spandex to shrink, just like the principle of thermal expansion and contraction, spandex will gradually shrink and deform under high temperature; at the same time, it can also cause the elasticity of spandex to decrease, making the fabric lose its original softness and elasticity and good recovery, thereby affecting the service life of the fabric and making the originally durable fabric become fragile.

[0005] Fourthly, there is a difficult-to-reconcile contradiction between the three-proofing performance and the air permeability. In the process of pursuing the three-proofing effect, it is often difficult to take into account the air permeability of the fabric. After the fabric is treated by the traditional three-proofing finishing process, the air permeability of the fabric often decreases by more than 30%. It is like that the fabric is put on a thick “armor”, although the stains and moisture from the outside are blocked, but the circulation of air is also hindered, so that the wearer feels stuffy and not breathable when moving, which greatly affects the comfort of wearing.

[0006] In summary, it has become a key problem to be solved in the field to develop a finishing process for polyester-nylon knitted fabric that can simultaneously take into account the stability of three-proofing effect, wash resistance, fabric mechanical properties and air permeability, and it is also an important direction to promote the further development of the polyester-nylon knitted fabric industry. SUMMARY

[0007] The purpose of the present application is to provide a three-proofing finishing process for polyester-nylon knitted fabric to solve the problems raised in the background art.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical solution: Step 1: fine pretreatment A low-temperature environmentally friendly cleaning system is used to achieve deep cleaning while avoiding nylon aging, which specifically includes: Pre-washing: immerse the polyester-nylon knitted fabric in deionized water at 40-50℃, add 0.5-1g / L of alkaline protease (enzyme activity ≥ 20 million U / g), and stir and clean for 10-15 minutes. The alkaline protease can specifically decompose protein impurities (such as protein additives remaining from the spinning process) on the surface of the fabric, and the low-temperature environment (40-50℃) can ensure enzyme activity and avoid premature aging of nylon due to high temperature.

[0009] Main washing: change the washing liquid, add 1-2g / L of environmentally friendly non-ionic surfactant (such as fatty alcohol polyoxyethylene ether AEO-9) and 0.3-0.5g / L of sodium citrate (pH buffer), maintain the temperature at 40-50℃, the bath ratio is 1:15-1:20, and stir and clean for 15-20 minutes. The non-ionic surfactant can efficiently remove oil stains and spinning oil, and the sodium citrate can maintain the stability of the system pH, avoiding damage to the fiber due to acid-alkali fluctuations.

[0010] Neutralization: add 0.1-0.2g / L of glacial acetic acid, adjust the pH to 6.5-7.0, and clean for 5 minutes. Neutralize the residual alkali to provide a neutral environment for the subsequent finishing agent to adhere, avoiding the influence of acid and alkali on the stability of the finishing agent.

[0011] Dehydration: Use centrifugal dehydrator, speed 800-1000r / min, dehydration to water content ≤30%. Control the water content to avoid excessive dilution of finishing agent during subsequent padding, ensuring stable adhesion.

[0012] Step 2: Three-proofing finishing agent padding treatment Three-proofing finishing agent formula (mass percentage): Fluorine-containing copolymer (such as perfluoroalkyl ethyl acrylate, solid content 30%) 8-12%, water-based isocyanate crosslinking agent (NCO content 12%) 1-3%, silicone penetrant (such as polyether modified silicone oil) 0.5-1%, deionized water to 100%; adjust pH to 5.0-6.0 with citric acid, stir evenly and stand for 10 minutes. Fluorine-containing copolymer is the core component of three-proofing function, which can form a low surface energy layer on the fiber surface; water-based isocyanate crosslinking agent enhances the bonding force through covalent reaction with fiber and fluorine-containing copolymer, improving wash resistance; silicone penetrant promotes the diffusion of finishing agent into the fiber interior, avoiding uneven effect caused by only adhering to the surface.

[0013] Padding process: adopt two-dip-two-pad method, first padding pressure 0.2-0.25MPa (initial penetration), second padding pressure 0.25-0.3MPa (uniform adhesion), control the padding liquor rate to 45-55% (preferably 50%). Precise control of padding liquor rate can avoid waste of finishing agent or insufficient adhesion, ensuring process stability.

[0014] Step 3: Staged drying Use gradient heating method to reduce spandex heat damage: Pre-drying: temperature 80-100℃ (preferably 90℃), time 30-50 seconds (preferably 40 seconds), quickly remove more than 80% free water on the surface of the fabric to avoid water evaporation caused by subsequent high temperature, which may cause fabric shrinkage.

[0015] High temperature drying: temperature 150-160℃ (preferably 155℃), time 60-80 seconds (preferably 70 seconds), to make the finishing agent preliminary curing, the water content of the fabric after drying ≤5%. High temperature promotes the preliminary combination of finishing agent and fiber, while reducing the risk of spandex aging by shortening the time.

[0016] Step 4: Tension control setting Setting equipment: use needle plate stenter setting machine, tension 10-15N / m (adjust according to fabric gram weight, 170-200g / ㎡ corresponds to 10-12N / m), to avoid excessive tension leading to fabric stretching deformation or too small leading to shrinkage.

[0017] Setting parameters: temperature 150-170℃ (preferably 160℃), time 80-120 seconds (preferably 100 seconds), wind speed 8-10m / s. High temperature promotes the deep reaction of crosslinking agent with fiber and finishing agent, and uniform wind speed ensures uniform heating of the fabric, further improving the stability of the three-proofing effect.

[0018] Step 5: Post-treatment ripening Low-temperature ripening: place the set fabric in an environment with a temperature of 40-50℃ (preferably 45℃) and a relative humidity of 60-70%, and let it stand for 24-48 hours (preferably 36 hours) to promote the complete crosslinking and solidification of the finishing agent and enhance wash resistance.

[0019] Cold water washing: wash with 15-25℃ deionized water for 10-15 minutes to remove unbound free finishing agent and avoid residual finishing agent blocking the fiber gaps and affecting air permeability.

[0020] Air drying: natural air drying or low-temperature drying at 30-40℃ to avoid secondary heat damage and ensure fabric elasticity and air permeability.

[0021] Preferably, the composition of the polyester-nylon knitted fabric is 90% polyester fiber + 10% spandex, with a grammage of ≥170g / m².

[0022] Preferably, the non-ionic surfactant in step one is fatty alcohol polyoxyethylene ether AEO-9.

[0023] Preferably, in step two, the fluorine-containing copolymer is perfluoroalkyl ethyl acrylate with a solid content of 30%; the NCO content of the water-based isocyanate crosslinking agent is 12%; and the organic silicon penetrating agent is polyether modified silicone oil.

[0024] Preferably, in step two, the pick-up rate is 50%.

[0025] Preferably, in step three, the pre-drying temperature is 90℃ and the time is 40 seconds; and the high-temperature drying temperature is 155℃ and the time is 70 seconds.

[0026] Preferably, in step four, the setting temperature is 160℃ and the time is 100 seconds; and when the polyester-nylon knitted fabric has a grammage of 170-200g / m², the tension is 10-12N / m.

[0027] Preferably, in step five, the standing temperature is 45℃ and the time is 36 hours; and the deionized water temperature is 20℃ and the washing time is 12 minutes.

[0028] The beneficial effects of the present application are as follows: 1. The polyester-nylon knitted fabric treated by the process of the present application performs outstandingly in waterproofing, oil-repellent and stain removal. The waterproofing level reaches or exceeds level 4 in GB / T 4745-2012 standard, meaning that the fabric can withstand at least 10 kPa of hydrostatic pressure without water penetration. The oil-repellent level reaches level 5 or above in AATCC 118-2013 standard, showing extremely strong resistance to oil stain adhesion. The stain removal rate is as high as 90% or above, effectively resisting various daily stains. This stable and efficient three-proofing performance ensures the fabric's persistent cleanliness and beauty in various use scenarios. 2. By optimizing the finishing agent formula and padding process, the fabric's waterproofing and oil-repellent levels can still maintain more than 80% of the initial value after 20 standard washes. This improvement significantly extends the fabric's service life, reduces performance degradation caused by frequent washing, and meets consumers' demand for high-quality and durable products. While improving the fabric's three-proofing performance, this process also considers its breathability. The treated fabric's air permeability reaches or exceeds 1000 mm / s, far superior to that of fabrics treated by traditional processes (usually not more than 700 mm / s). This good breathability ensures the fabric's comfort during wear, keeping it dry and breathable even in humid or high-temperature environments. 3. By using low-temperature pretreatment technology (40-50℃ alkaline protease cleaning), the process avoids damage to spandex fibers caused by high temperatures, effectively preventing the elastic decline caused by spandex aging. At the same time, the segmented drying and tension control setting technology further reduces the negative impact of thermal and mechanical stress on the fabric, ensuring that the spandex breaking elongation retention rate is not less than 90%, thereby maintaining the fabric's original elasticity and service life. The parameters of each step in this process are clear and easy to operate, providing reliable technical support for industrial mass production. From fine pretreatment to three-proofing finishing agent padding, to segmented drying, tension control setting, and post-treatment curing, each step is carefully designed and optimized to ensure the stability and consistency of the process. At the same time, this process can be flexibly adjusted according to different fabric weights, showing strong adaptability and versatility, meeting the market's diversified needs. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The three-proofing finishing process flow chart for the polyester-nylon knitted fabric of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0031] As Figure 1 shown, the embodiment of the present application provides a three-proofing finishing process for polyester and nylon knitted fabric; Example 1 Fabric: 90% polyester fiber + 10% spandex, 170g / m2.

[0032] Process steps: Fine pretreatment: Pre-washing: 45℃ deionized water, add 0.8g / L alkaline protease (enzyme activity 200,000 U / g), stirring and cleaning for 12 minutes; Main washing: change the washing solution, add 1.5g / L AEO-9 and 0.4g / L sodium citrate, 45℃, bath ratio 1:18, stirring and cleaning for 18 minutes; Neutralization: add 0.15g / L glacial acetic acid, adjust pH to 6.8, clean for 5 minutes; Dehydration: centrifugal dehydration at 900r / min, moisture content 28%.

[0033] Three-proofing finishing agent padding: Finishing agent formula: 10% perfluoroalkyl ethyl acrylate (solid content 30%) + 2% water-based isocyanate (NCO content 12%) + 0.8% polyether modified silicone oil, deionized water to 100%, citric acid to adjust pH to 5.5; Double padding: first pressure 0.23MPa, second pressure 0.28MPa, padding rate 50%.

[0034] Segmented drying: Pre-drying: 90℃, 40 seconds; High temperature drying: 155℃, 70 seconds, moisture content 4%.

[0035] Tension control setting: Needle plate tentering machine, tension 12N / m, 160℃, 100 seconds, air speed 9m / s.

[0036] Post-treatment curing: 45℃, relative humidity 65% environment for 36 hours; 20℃ deionized water cleaning for 12 minutes; Natural air drying.

[0037] Test results: waterproof level 4, oil repellency level 5, stain removal rate 92%; waterproof level 3, oil repellency level 4 after 20 times of washing; spandex elongation retention rate 92%; air permeability 1050mm / s.

[0038] Example 2 Fabric: 90% polyester fiber + 10% spandex, 200g / m2.

[0039] Process steps: Fine pretreatment: Pre-washing: 50°C deionized water, add 1g / L alkaline protease (enzyme activity 200,000 U / g), stirring for 15 minutes; Main washing: change the washing solution, add 2g / L AEO-9 and 0.5g / L sodium citrate, 50°C, bath ratio 1:20, stirring for 20 minutes; Neutralization: add 0.2g / L glacial acetic acid, adjust pH to 7.0, wash for 5 minutes; Dehydration: centrifugal dehydration at 1000r / min, moisture content 25%.

[0040] Three-proofing finishing agent padding: Finishing agent formula: 12% perfluoroalkyl ethyl acrylate (solid content 30%) + 3% water-based isocyanate (NCO content 12%) + 1% polyether modified silicone oil, deionized water to 100%, citric acid to adjust pH to 6.0; Double padding: first pressure 0.25MPa, second pressure 0.3MPa, pick-up rate 55%.

[0041] Segmented drying: Pre-drying: 100°C, 50 seconds; High temperature drying: 160°C, 80 seconds, moisture content 3%.

[0042] Tension control setting: Needle plate tentering machine, tension 15N / m, 170°C, 120 seconds, air speed 10m / s.

[0043] Post-treatment curing: 50°C, relative humidity 70% environment for 48 hours; 25°C deionized water washing for 15 minutes; 40°C low temperature drying.

[0044] Test results: waterproof level 5, oil repellency level 6, stain removal rate 95%; after 20 times of washing, waterproof level 4, oil repellency level 5; spandex elongation retention rate 91%; air permeability 1020mm / s.

[0045] The person skilled in the art can know that the parameters in the above embodiments can be fine-tuned according to the actual fabric characteristics (such as thickness, density), as long as the core idea of the fine pretreatment, segmented drying, tension setting and post-treatment maturation of the application is followed, all belong to the protection scope of the application.

[0046] It should be noted that, in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0047] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A process for finishing a polyester-nylon knitted fabric against water, oil and dirt, characterized in that: The process comprises the following steps: Step one, fine pretreatment: using low-temperature environmental cleaning system to treat polyester and nylon knitted fabric, including pre-washing, main washing, neutralization and dehydration; The pre-washing is to immerse the polyester and nylon knitted fabric in deionized water at 40-50℃, add 0.5-1g / L of alkaline protease, and stir for 10-15 minutes; the main washing is to add 1-2g / L of non-ionic surfactant and 0.3-0.5g / L of sodium citrate after changing the washing liquid, and stir for 15-20 minutes at 40-50℃ with a bath ratio of 1:15-1:20; the neutralization is to add 0.1-0.2g / L of glacial acetic acid to adjust the pH to 6.5-7.0, and wash for 5 minutes; the dehydration is to use a centrifugal dehydrator at a speed of 800-1000r / min to dehydrate to a moisture content of ≤30%; Step two, three-proofing finishing agent dip treatment: immerse the pretreated polyester and nylon knitted fabric in three-proofing finishing agent, and use two-dip-two-pad method for treatment; the three-proofing finishing agent comprises, by mass percentage, 8-12% of fluorine-containing copolymer, 1-3% of water-based isocyanate crosslinking agent, 0.5-1% of organic silicon penetrant, and the balance of deionized water, and the pH is adjusted to 5.0-6.0 with citric acid; Step three, segmented drying: pre-drying and high-temperature drying are carried out in sequence; the pre-drying temperature is 80-100℃, and the time is 30-50 seconds; the high-temperature drying temperature is 150-160℃, and the time is 60-80 seconds, and the moisture content of the dried fabric is ≤5%; Step four, tension control setting: using a needle plate stenter setting machine, setting at a temperature of 150-170℃ under a tension of 10-15N / m for 80-120 seconds, and the wind speed is 8-10m / s; Step five, post-treatment curing: the set fabric is placed in an environment of 40-50℃ and 60-70% relative humidity for 24-48 hours, then washed with 15-25℃ deionized water for 10-15 minutes, and finally dried.

2. A process for finishing a polyester- cotton knitted fabric with a three-protective finish according to claim 1, characterized in that: The polyester and nylon knitted fabric comprises 90% polyester fiber and 10% spandex, and the grammage is ≥170g / m2.

3. The process as claimed in claim 1, wherein the process is carried out by using a three-proofing finishing agent. The non-ionic surfactant in step one is fatty alcohol polyoxyethylene ether AEO-9.

4. The process as claimed in claim 1, wherein the process is carried out by using a three-proofing finishing agent. The fluorine-containing copolymer in step two is perfluoroalkyl ethyl acrylate with a solid content of 30%; the NCO content of the water-based isocyanate crosslinking agent is 12%; the organic silicon penetrant is polyether modified silicone oil.

5. A process for finishing a polyester- cotton knitted fabric with a three-protective finish according to claim 1, characterized in that: The padding rate in step two is 50%.

6. A process for finishing a polyester- cotton knitted fabric with a three-protective finish according to claim 1, characterized in that: The pre-drying temperature in step three is 90℃, and the time is 40 seconds; the high-temperature drying temperature is 155℃, and the time is 70 seconds.

7. The process as claimed in claim 1, wherein the process is carried out by using a three-proofing finishing agent. The setting temperature in step four is 160℃, and the time is 100 seconds; when the polyester and nylon knitted fabric has a grammage of 170-200g / m2, the tension is 10-12N / m.

8. The process as claimed in claim 1, wherein the process is carried out by using a three-proofing finish of polyester-nylon knitted fabric. The standing temperature in step five is 45℃, and the time is 36 hours; the deionized water temperature is 20℃, and the washing time is 12 minutes.

9. The process as claimed in claim 1, wherein the process is carried out by using a three-proofing finishing agent for polyester-nylon knitted fabric. The first dip padding pressure in the two-dip-two-pad of step two is 0.2-0.25MPa, the second dip padding pressure is 0.25-0.3MPa, and the padding rate is 45-55%.

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