Preparation method of anti-yellowing chinlon 6 FDY (Fully Drawn Yarn)

Abstract

The invention provides a preparation method of anti-yellowing chinlon 6 FDY (Fully Drawn Yarn), and relates to the technical field of chinlon fiber preparation. The preparation method of the anti-yellowing chinlon 6 FDY comprises the following steps that chinlon 6 slices and composite anti-yellowing master batches are mixed according to the mass ratio of 95: 5, the composite anti-yellowing master batches comprise a hindered amine light stabilizer, a benzotriazole ultraviolet light absorber, a polylactic acid dispersing agent and a phosphite antioxidant, and the mixture is dried for 4-6 hours at the temperature of 80-100 DEG C after being mixed; melting the pretreated raw materials at 270-275 DEG C, dispersing through a static mixer, and conveying to a spinning assembly through a metering pump; the nascent fibers are sequentially subjected to gradient stretching through three drafting rollers, the total stretching multiple is 1.4-1.5 times, and the final winding speed is 5500-6000 m / min. Through a composite anti-yellowing system, the hindered amine light stabilizer, the benzotriazole ultraviolet light absorber, the polylactic acid dispersing agent, the phosphite antioxidant and other components are scientifically proportioned to form a synergistic effect.

Description

Technical Field

[0001] The invention relates to the technical field of nylon fiber preparation, in particular to a method for preparing yellowing-resistant nylon 6FDY. Background Art

[0002] Nylon 6 (polycaprolactam) fiber has excellent mechanical properties and wear resistance and is widely used in textiles, industrial materials and other fields. However, nylon 6 is prone to yellowing during high-temperature processing, long-term light exposure or storage, seriously affecting the product appearance and service life. In the existing technology, anti-yellowing methods mainly include:

[0003] 1. Post-finishing process: Surface treatment is performed by padding with anti-yellowing agents (such as anti-phenolic yellowing agents and anti-heat yellowing agents), but there are problems such as poor wash resistance and the effect decreases with the number of washes.

[0004] 2. Single additive blending: such as adding hindered amine light stabilizers (HALS) or benzotriazole UV absorbers, but the synergistic effect of a single system is insufficient and the anti-yellowing effect is limited.

[0005] 3. Spinning process optimization: such as nitrogen protection spinning, but the equipment is complex and the cost is high.

[0006] Therefore, it is of great significance to develop a method for preparing nylon 6FDY that does not require post-finishing, has long-lasting anti-yellowing properties, and is environmentally friendly. Summary of the Invention

[0007] (1) Technical problems solved

[0008] In response to the shortcomings of the existing technology, the present invention provides a method for preparing yellowing-resistant nylon 6FDY. Through the coordinated optimization of the composite anti-yellowing system and the spinning process, the long-term anti-yellowing performance of the fiber under high temperature and light is achieved, while the production process is simplified and the cost is reduced, thus solving the problems raised by the above-mentioned background technology.

[0009] (2) Technical solution

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for preparing anti-yellowing nylon 6FDY, comprising the following steps:

[0011] Step 1: Raw material pretreatment:

[0012] The nylon 6 chips were mixed with a composite anti-yellowing masterbatch in a mass ratio of 95:5, wherein the composite anti-yellowing masterbatch contained a hindered amine light stabilizer, a benzotriazole ultraviolet absorber, a polylactic acid dispersant, and a phosphite antioxidant, and the mixture was dried at 80-100° C. for 4-6 hours.

[0013] Step 2: Melt Spinning:

[0014] The pretreated raw materials are melted at 270-275°C, dispersed in a static mixer, and then transported to the spinning assembly through a metering pump. The spinning temperature is controlled at 270-273°C, and the side blowing parameters are wind temperature 20-25°C, wind speed 0.3-0.5m / s, and relative humidity 75-85%.

[0015] Step 3: Stretch and shape:

[0016] The spun fibers are sequentially stretched by three drafting rollers for gradient stretching, with a total stretching ratio of 1.4-1.5 times and a final winding speed of 5500-6000 m / min.

[0017] Preferably, in step 1, the mass percentages of the components in the composite anti-yellowing masterbatch are: 20-30% hindered amine light stabilizer, 10-15% benzotriazole ultraviolet absorber, 5-10% polylactic acid dispersant, 5-8% phosphite antioxidant, and the balance is nylon 6 carrier resin.

[0018] Preferably, the hindered amine light stabilizer is RIASORB UV-2020, and the benzotriazole ultraviolet absorber is UV-327.

[0019] Preferably, the molecular weight of the polylactic acid dispersant is 800-5000 g / mol, and a dispersed structure in which the molecular segments are compatible with nylon 6 is formed in the masterbatch.

[0020] Preferably, the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, which forms a free radical capture synergistic system with the hindered amine light stabilizer in the masterbatch.

[0021] Preferably, in step 2, the composite anti-yellowing masterbatch is prepared by a twin-screw extruder with an extrusion temperature of 240-250° C. and a screw speed of 200-300 r / min.

[0022] Preferably, in step 2, the diameter of the spinneret holes of the spinning assembly is 0.2-0.3 mm, and the number of holes is 36-72 holes.

[0023] Preferably, in step three, in the stretching and shaping process:

[0024] The temperature of the first drafting roller is 60-70℃, the speed is 4000-4500m / min, and the stretching ratio is 1.2-1.3 times;

[0025] The temperature of the second drafting roller is 90-100℃, the speed is 5000-5500m / min, and the stretching ratio is 1.1-1.2 times;

[0026] The temperature of the third drafting roller is 110-120°C, the speed is 5500-6000m / min, and the stretching ratio is 1.05-1.1 times.

[0027] (3) Beneficial effects

[0028] The present invention provides a method for preparing yellowing-resistant nylon 6FDY, which has the following beneficial effects:

[0029] 1. The combination of hindered amine light stabilizers and benzotriazole UV absorbers synergistically improves the anti-yellowing effect through the dual mechanisms of capturing free radicals and absorbing UV rays. The polylactic acid dispersant enhances the dispersion of the masterbatch in nylon 6 and prevents agglomeration.

[0030] 2. By combining anti-yellowing masterbatch (hindered amines + benzotriazoles) with spinning process optimization, the anti-yellowing performance of the fiber is significantly improved, without the need for post-finishing, which is environmentally friendly and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1:

[0034] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing yellowing-resistant nylon 6FDY, comprising the following steps:

[0035] Step 1: Raw material pretreatment:

[0036] Nylon 6 chips and composite anti-yellowing masterbatch are mixed in a mass ratio of 95:5, wherein the composite anti-yellowing masterbatch is composed of the following components (mass percentage):

[0037] Hindered amine light stabilizer (RIASORB UV-2020): 20%;

[0038] Benzotriazole UV absorber (UV-327): 10%;

[0039] Polylactic acid dispersant: 5%, wherein the molecular weight of the polylactic acid dispersant is 800 g / mol, and the molecular chain segments formed in the masterbatch are dispersed in a structure compatible with nylon 6;

[0040] Phosphite antioxidant: 5%, wherein the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, which forms a free radical capture synergistic system with the hindered amine light stabilizer in the masterbatch;

[0041] Carrier resin (nylon 6): balance;

[0042] After mixing, dry at 80°C for 4 hours to remove moisture;

[0043] Step 2: Melt Spinning:

[0044] The pretreated raw materials were added to the screw extruder at an extrusion temperature of 240°C, a screw speed of 200 r / min, and a melt temperature controlled at 270°C. After being dispersed in a static mixer, the raw materials were transported to the spinning assembly by a metering pump. The spinneret diameter of the spinning assembly was 0.2 mm, the number of holes was 36, the spinning temperature was controlled at 270°C, and the side blowing parameters were a wind temperature of 20°C, a wind speed of 0.3 m / s, and a relative humidity of 75%.

[0045] Step 3: Stretch and shape:

[0046] The spun fiber is sequentially stretched by three drafting rollers with a total stretching ratio of 1.4 times and a final winding speed of 5500m / min. Specifically:

[0047] The temperature of the first drafting roller is 60°C, the speed is 4000m / min, and the stretching ratio is 1.2 times;

[0048] The second drafting roller temperature is 90°C, the speed is 5000m / min, and the stretching ratio is 1.1 times;

[0049] The temperature of the third drafting roller is 110° C., the speed is 5500 m / min, and the stretching ratio is 1.05 times.

[0050] Example 2:

[0051] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing yellowing-resistant nylon 6FDY, comprising the following steps:

[0052] Step 1: Raw material pretreatment:

[0053] Nylon 6 chips and composite anti-yellowing masterbatch are mixed in a mass ratio of 95:5, wherein the composite anti-yellowing masterbatch is composed of the following components (mass percentage):

[0054] Hindered amine light stabilizer (RIASORB UV-2020): 25%;

[0055] Benzotriazole UV absorber (UV-327): 13%;

[0056] Polylactic acid dispersant: 8%, wherein the polylactic acid dispersant has a molecular weight of 3000 g / mol and forms a dispersed structure in the masterbatch in which the molecular segments are compatible with nylon 6;

[0057] Phosphite antioxidant: 7%, wherein the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, which forms a free radical capture synergistic system with the hindered amine light stabilizer in the masterbatch;

[0058] Carrier resin (nylon 6): balance;

[0059] After mixing, dry at 90°C for 5 hours to remove moisture;

[0060] Step 2: Melt Spinning:

[0061] The pretreated raw materials were added to the screw extruder at an extrusion temperature of 245°C, a screw speed of 250 r / min, and a melt temperature controlled at 273°C. After being dispersed in a static mixer, the raw materials were transported to the spinning assembly by a metering pump. The spinneret diameter of the spinning assembly was 0.3 mm, the number of holes was 48, the spinning temperature was controlled at 272°C, and the side blowing parameters were a wind temperature of 23°C, a wind speed of 0.4 m / s, and a relative humidity of 80%.

[0062] Step 3: Stretch and shape:

[0063] The spun fiber is sequentially stretched by three drafting rollers with a total stretching ratio of 1.5 times and a final winding speed of 5800 m / min. Specifically:

[0064] The temperature of the first drafting roller is 65°C, the speed is 4200m / min, and the stretching ratio is 1.2 times;

[0065] The second drafting roller temperature is 95°C, the speed is 5300 m / min, and the stretching ratio is 1.2 times;

[0066] The temperature of the third drafting roller is 115° C., the speed is 5800 m / min, and the stretching ratio is 1.05 times.

[0067] Example 3:

[0068] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing yellowing-resistant nylon 6FDY, comprising the following steps:

[0069] Step 1: Raw material pretreatment:

[0070] Nylon 6 chips and composite anti-yellowing masterbatch are mixed in a mass ratio of 95:5, wherein the composite anti-yellowing masterbatch is composed of the following components (mass percentage):

[0071] Hindered amine light stabilizer (RIASORB UV-2020): 30%;

[0072] Benzotriazole UV absorber (UV-327): 15%;

[0073] Polylactic acid dispersant: 10%, wherein the polylactic acid dispersant has a molecular weight of 5000 g / mol and forms a dispersed structure in the masterbatch in which the molecular segments are compatible with nylon 6;

[0074] Phosphite antioxidant: 8%, wherein the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, which forms a free radical capture synergistic system with the hindered amine light stabilizer in the masterbatch;

[0075] Carrier resin (nylon 6): balance;

[0076] After mixing, dry at 100°C for 6 hours to remove moisture;

[0077] Step 2: Melt Spinning:

[0078] The pretreated raw materials were added to the screw extruder at an extrusion temperature of 250°C, a screw speed of 300 r / min, and a melt temperature controlled at 275°C. After being dispersed in a static mixer, the raw materials were transported to the spinning assembly by a metering pump. The spinneret diameter of the spinning assembly was 0.3 mm, the number of holes was 72, the spinning temperature was controlled at 273°C, and the side blowing parameters were a wind temperature of 25°C, a wind speed of 0.5 m / s, and a relative humidity of 85%.

[0079] Step 3: Stretch and shape:

[0080] The spun fiber is sequentially stretched by three drafting rollers with a total stretching ratio of 1.5 times and a final winding speed of 6000 m / min. Specifically:

[0081] The temperature of the first drafting roller is 70°C, the speed is 4500m / min, and the stretching ratio is 1.3 times;

[0082] The second drafting roller temperature is 100°C, the speed is 5500m / min, and the stretching ratio is 1.1 times;

[0083] The temperature of the third drafting roller is 120° C., the speed is 6000 m / min, and the stretching ratio is 1.05 times.

[0084] Comparative Example:

[0085] A method for preparing yellowing-resistant nylon 6FDY comprises the following steps:

[0086] Step 1: Raw material pretreatment:

[0087] Nylon 6 chips and hindered amine masterbatch were mixed at a mass ratio of 95:5, and then dried at 80°C for 4 hours to remove moisture;

[0088] Step 2: Melt Spinning:

[0089] The pretreated raw materials were added to the screw extruder at an extrusion temperature of 240°C, a screw speed of 200 r / min, and a melt temperature controlled at 270°C. After being dispersed in a static mixer, the raw materials were transported to the spinning assembly by a metering pump. The spinneret diameter of the spinning assembly was 0.2 mm, the number of holes was 36, the spinning temperature was controlled at 270°C, and the side blowing parameters were a wind temperature of 20°C, a wind speed of 0.3 m / s, and a relative humidity of 75%.

[0090] Step 3: Stretch and shape:

[0091] The spun fiber is sequentially stretched by three drafting rollers with a total stretching ratio of 1.4 times and a final winding speed of 5500m / min. Specifically:

[0092] The temperature of the first drafting roller is 60°C, the speed is 4000m / min, and the stretching ratio is 1.2 times;

[0093] The second drafting roller temperature is 90°C, the speed is 5000m / min, and the stretching ratio is 1.1 times;

[0094] The temperature of the third drafting roller is 110° C., the speed is 5500 m / min, and the stretching ratio is 1.05 times.

[0095] Experimental example:

[0096] The performance of nylon 6FDY prepared in Example 1, Example 2, Example 3 and the comparative example was tested, and the results are shown in the following table:

[0097]

[0098] In summary, the nylon 6FDY prepared by the present invention has the following significant effects:

[0099] 1. Significant long-term anti-yellowing performance. The present invention uses a composite anti-yellowing system to scientifically proportion multiple ingredients such as hindered amine light stabilizers, benzotriazole UV absorbers, polylactic acid dispersants and phosphite antioxidants to form a synergistic effect. Hindered amine light stabilizers can effectively capture free radicals, benzotriazole UV absorbers can absorb ultraviolet energy, and phosphite antioxidants form a free radical capture synergistic system with hindered amine light stabilizers to resist fiber yellowing factors from multiple aspects. Under high temperature and light conditions, the color stability of the fiber can be maintained for a long time, avoiding the problem of limited anti-yellowing effect of single additive blends in the prior art, and ensuring the long-lasting beauty of nylon 6FDY during actual use.

[0100] 2. The production process is environmentally friendly and streamlined. The direct blending of a composite anti-yellowing masterbatch and nylon 6 chips eliminates the need for post-finishing, reduces chemical use and wastewater discharge during production, and complies with environmental protection requirements. This also avoids the drawback of poor washability associated with surface treatment, simplifies the production process, and improves efficiency. Optimized spinning process parameters, such as precise control of melt temperature, spinning temperature, side-blowing parameters, and stretching and shaping, reduce production costs while ensuring fiber quality, addressing the complex and high-cost challenges of traditional nitrogen-shielded spinning equipment.

[0101] 3. Excellent comprehensive fiber performance. As can be seen from the experimental data, the nylon 6FDY prepared by the present invention has high breaking strength. The breaking strengths of Examples 1, 2, and 3 all reach 5.2-5.3 cN / dtex, which is much higher than the 3.4 cN / dtex of the comparative example, indicating that the fiber has good physical strength and durability. The elastic recovery rate is also high, reaching 98-99%, while the comparative example is only 76%. This shows that the nylon 6FDY of the present invention can better recover its original shape after being deformed by force, and has a wider applicability and better user experience in textile applications. In addition, the yellowing index is low. The yellowing index of Examples 1, 2, and 3 is all 1.1-1.2, which is significantly lower than 3.5 of the comparative example, fully demonstrating its excellent anti-yellowing performance.

[0102] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing yellowing-resistant nylon 6FDY, characterized by: The following steps are involved: Step 1: Raw material pretreatment: The nylon 6 chips were mixed with a composite anti-yellowing masterbatch in a mass ratio of 95:5, wherein the composite anti-yellowing masterbatch contained a hindered amine light stabilizer, a benzotriazole ultraviolet absorber, a polylactic acid dispersant, and a phosphite antioxidant, and the mixture was dried at 80-100° C. for 4-6 hours. Step 2: Melt Spinning: The pretreated raw materials are melted at 270-275°C, dispersed in a static mixer, and then transported to the spinning assembly through a metering pump. The spinning temperature is controlled at 270-273°C, and the side blowing parameters are wind temperature 20-25°C, wind speed 0.3-0.5m / s, and relative humidity 75-85%. Step 3: Stretch and shape: The spun fibers are sequentially stretched by three drafting rollers for gradient stretching, with a total stretching ratio of 1.4-1.5 times and a final winding speed of 5500-6000 m / min.

2. The method for preparing yellowing-resistant nylon 6FDY according to claim 1, wherein: In step 1, the mass percentages of the components in the composite anti-yellowing masterbatch are: 20-30% hindered amine light stabilizer, 10-15% benzotriazole ultraviolet absorber, 5-10% polylactic acid dispersant, 5-8% phosphite antioxidant, and the balance is nylon 6 carrier resin.

3. The method for preparing yellowing-resistant nylon 6FDY according to claim 2, wherein: The hindered amine light stabilizer is RIASORB UV-2020, and the benzotriazole ultraviolet absorber is UV-327.

4. The method for preparing yellowing-resistant nylon 6FDY according to claim 2, wherein: The polylactic acid dispersant has a molecular weight of 800-5000 g / mol and forms a dispersed structure in which the molecular segments are compatible with nylon 6 in the masterbatch.

5. The method for preparing yellowing-resistant nylon 6FDY according to claim 2, wherein: The phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, which forms a free radical capture synergistic system with the hindered amine light stabilizer in the masterbatch.

6. The method for preparing yellowing-resistant nylon 6FDY according to claim 1, wherein: In step 2, the composite anti-yellowing masterbatch is prepared by a twin-screw extruder with an extrusion temperature of 240-250° C. and a screw speed of 200-300 r / min.

7. The method for preparing yellowing-resistant nylon 6FDY according to claim 1, wherein: In step 2, the diameter of the spinneret holes of the spinning assembly is 0.2-0.3 mm, and the number of holes is 36-72 holes.

8. The method for preparing yellowing-resistant nylon 6FDY according to claim 1, wherein: In step three, in the stretching and shaping process: The temperature of the first drafting roller is 60-70℃, the speed is 4000-4500m / min, and the stretching ratio is 1.2-1.3 times; The temperature of the second drafting roller is 90-100℃, the speed is 5000-5500m / min, and the stretching ratio is 1.1-1.2 times; The temperature of the third drafting roller is 110-120°C, the speed is 5500-6000m / min, and the stretching ratio is 1.05-1.1 times.

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