Anti-aging composite material and PA6 fiber multistage synergistic anti-oxidation aging treatment method

Abstract

The invention relates to the technical field of high-molecular compounds, and provides an anti-aging composite material and a multi-stage synergistic anti-oxidation aging treatment method for PA6 fiber, the anti-aging composite material comprises the following components by mass: 94-97% of PA6 resin; 1.5 to 3% of a composite antioxidant; 0.8-2% of modified cerium oxide; and 0.5-1% of a lubricant. The preparation method of the modified cerium oxide comprises the following steps: weighing a predetermined amount of nano cerium oxide and a predetermined amount of a silane coupling agent; the preparation method comprises the following steps: preparing a solution with the concentration of 10% from a silane coupling agent, and heating for hydrolysis reaction to prepare a hydrolyzed silane coupling agent; and adding nano cerium oxide, and heating to generate a coupling reaction, thereby obtaining the modified cerium oxide. Therefore, the composite antioxidant and the modified cerium oxide respectively generate unique antioxidant effects in each oxidation stage of fiber production. The anti-aging capability of the fiber is obviously improved. And the smoothness of the fiber surface is better, the spinning end breakage rate is low, and the quality of a textile finished product is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer compounds, and particularly relates to an anti-aging composite material and a multi-stage synergistic anti-oxidation aging treatment method for PA6 fibers. Background Art

[0002] PA6 (polycaprolactam) fibers are widely used in fields such as automobiles and textiles due to their high strength, wear resistance, and chemical resistance. However, the amide bonds in its molecular chain are easily affected by thermal oxygen aging and ultraviolet rays, resulting in a decline in mechanical properties.

[0003] Existing disclosed anti-aging methods, such as a highly wear-resistant glass fiber-reinforced nylon material and its preparation method disclosed in Chinese Patent Application CN117844242A, "Weigh nylon resin, antioxidant, lubricant, wear-resistant agent, nano-ceria, titanium dioxide, and coupling agent according to parts by weight, and uniformly mix the above raw material components and add them from the main feeding port of a twin-screw extruder." This application adds anti-aging components such as antioxidants, nano-ceria, and coupling agents together during the mixing process, making the overall anti-aging effect of the product a mechanical superposition of the effects of each component, resulting in a "bottleneck" in the improvement of the product's anti-aging performance. Summary of the Invention

[0004] Aiming at the above defects, the present invention mainly provides an anti-aging composite material to solve the technical problem of the bottleneck in the improvement of the anti-aging performance of PA6 products.

[0005] To solve the above problems, the present invention provides an anti-aging composite material, which includes the following components by mass percentage: PA6 resin: 94 - 97%; Compound antioxidant: 1.5 - 3%; Modified cerium oxide: 0.8 - 2%; Lubricant: 0.5 - 1%.

[0006] According to the anti-aging composite material of the present invention, the compound antioxidant is a compound of AT-168 and AT-626, and the weight ratio of the two is 2:1.

[0007] According to the anti-aging composite material of the present invention, the preparation steps of the compound antioxidant are: weigh AT-168 and AT-626 respectively according to the weight ratio, and then mix them at a rotation speed of 20 - 30 rpm for 30 - 40 minutes.

[0008] According to the anti-aging composite material of the present invention, AT-168 and AT-626 of the compound antioxidant are dried before mixing; The steps of the drying treatment are: place the two in a vacuum drying oven at a temperature of 60 ± 5°C, a vacuum degree of ≤100 Pa, and dry for 4 - 6 hours.

[0009] For the anti-aging composite material according to the present invention, the preparation steps of the modified cerium oxide include: Weigh a predetermined amount of nano cerium oxide and silane coupling agent, and the mass ratio of the two is 1: 0.05-0.2; Configure the silane coupling agent into a 10% concentration solution, heat it to undergo a hydrolysis reaction to obtain a hydrolyzed silane coupling agent; Then add nano cerium oxide, heat it to undergo a coupling reaction to obtain modified cerium oxide; the heating temperature is 120 °C, and the reaction time is: 30-100 min.

[0010] For the anti-aging composite material according to the present invention, the particle size of the nano cerium oxide does not exceed 50 nm.

[0011] For the anti-aging composite material according to the present invention, the lubricant is calcium stearate.

[0012] A multi-stage synergistic antioxidant aging treatment method for PA6 fibers includes the following steps: S1. Prepare the materials of each component according to the mass ratio of the anti-aging composite material described above; S2. Divide the compound antioxidant into two equal parts; S3. In the initial stage of the melt spinning of PA6 resin, the melting temperature ≤ 220 °C; add the first part of the compound antioxidant; S4. In the final stage of the melt spinning of PA6 resin, the melting temperature is 240-260 °C; add the second part of the compound antioxidant and modified cerium oxide; S5. In the wire drawing and cooling stage, perform microwave irradiation treatment on the PA6 fibers; microwave frequency: 2.45 GHz; irradiation power: 300-500 W; irradiation time: 10-20 s.

[0013] For the multi-stage synergistic antioxidant aging treatment method of PA6 fibers according to the present invention, the PA6 resin in step S1 is vacuum dried at 100 °C for 4 hours to make its moisture content ≤ 0.02%.

[0014] For the multi-stage synergistic antioxidant aging treatment method of PA6 fibers according to the present invention, the lubricant is added in step S3.

[0015] In summary, for the anti-aging composite material of the present invention, its compound antioxidant and modified cerium oxide respectively produce unique antioxidant effects in each oxidation stage of fiber production. The present invention also provides a multi-stage synergistic antioxidant aging treatment method for PA6 fibers, which significantly improves the anti-aging ability of the fibers. And the smoothness of the fiber surface is good, the spinning breakage rate is low, and the quality of the textile finished product is improved. Description of the Drawings

[0016] Figure 1It is the schematic diagram of the hydrolysis reaction of the silane coupling agent of the present invention; Figure 2 It is the schematic diagram of the coupling reaction between cerium oxide and hydrolyzed KH-550 of the present invention; Figure 3 It is the schematic diagram of the grafting reaction between the modified cerium oxide and PA6 of the present invention. Specific embodiments

[0017] See Figure 1 , the present invention provides an anti-aging composite material, which includes the following components by mass percentage: PA6 resin: 94-97%; Compound antioxidant: 1.5-3%; Modified cerium oxide: 0.8-2%; Lubricant: 0.5-1%.

[0018] Optionally, the lubricant of the present invention is calcium stearate.

[0019] As an embodiment, the compound antioxidant of the present invention is a compound of AT-168 and AT-626, and the weight ratio of the two is 2:1; Furthermore, the preparation steps of the compound antioxidant are: respectively weigh 250 g of AT-168 (chemical name: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], white powder) and AT-626 (chemical name: bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, light yellow powder) according to the weight ratio; then add the two into the mixing bin of a high-speed mixer and mix at a speed of 20-30 rpm for 30-40 minutes.

[0020] To prevent the antioxidant from hydrolysis or caking due to moisture during the subsequent melting process. Preferably, AT-168 (hindered phenol type) and AT-626 (phosphite type) of the compound antioxidant of the present invention are dried before mixing; The steps of the drying treatment are: place the two in a vacuum drying oven at a temperature of 60±5°C, a vacuum degree of ≤100 Pa, and dry for 4-6 hours.

[0021] As an embodiment, the preparation steps of the modified cerium oxide of the present invention include: Weigh a predetermined amount of nano-cerium oxide and silane coupling agent (KH-550), and the mass ratio of the two is 1: 0.05-0.2; See Figure 1 , configure the silane coupling agent into a 10% concentration solution, heat it to undergo a hydrolysis reaction, and obtain a hydrolyzed silane coupling agent; See Figure 2, and then cerium oxide nanoparticles are added, and a coupling reaction occurs upon heating to obtain modified cerium oxide; the heating temperature is 120 °C, and the reaction time is 30 - 100 min.

[0022] Optionally, the cerium oxide nanoparticles have a particle size not exceeding 50 nm and good dispersibility.

[0023] The present invention also provides a method for multi-stage synergistic antioxidant aging treatment of PA6 fibers, comprising the following steps: S1, prepare the materials of each component according to the mass ratio of the anti-aging composite material; As a preferred embodiment, the PA6 resin is vacuum dried at 100 °C for 4 hours to make its moisture content ≤ 0.02%; S2, divide the compound antioxidant into two equal parts; S3, in the initial stage of the melt spinning of PA6 resin, the melting temperature ≤ 220 °C; add the first part of the compound antioxidant; In the present invention, the compound antioxidant is added in the initial stage of the melting of PA6 (temperature ≤ 220 °C). AT-168 in the compound antioxidant captures free radicals through a hydrogen donation mechanism, can scavenge free radicals in the initial stage of the oxidation of the PA6 melt, and inhibits the oxidation of the PA6 melt at this stage.

[0024] S4, in the final stage of the melt spinning of PA6 resin, the melting temperature is 240 - 260 °C; add the second part of the compound antioxidant and the modified cerium oxide; AT-626 in the compound antioxidant of the present invention decomposes hydroperoxides to eliminate peroxides generated during the oxidation of the PA6 melt, and forms a "dual blocking" mechanism with AT-168 to achieve dynamic complementarity and inhibit the oxidation of the PA6 melt during the extrusion process.

[0025] At the same time, the decomposition temperatures of AT-626 (decomposition temperature ≥ 220 °C) and AT-168 (decomposition temperature ≤ 180 °C) are different, and the two form a complementarity in different melting temperature ranges to avoid gaps in inhibiting oxidation.

[0026] See Figure 3 , and the modified cerium oxide undergoes a grafting reaction with PA6.

[0027] In the present invention, the modified cerium oxide is added in the later stage of the extrusion of the PA6 melt (melting temperature 240 - 260 °C), which can reduce its decomposition at high temperatures and retain sufficient reactants for subsequent grafting reactions. Under the action of the shear force of the extruder, the modified cerium oxide powder is uniformly dispersed in the PA6 melt, improving the degree of completion of the grafting reaction.

[0028] At the same time, the modified cerium oxide particles can also fill the surface microcracks of PA6, reduce the oxygen permeation rate, and improve the antioxidant ability of PA6 in the high-temperature range (240 - 260 °C) of melt spinning.

[0029] Preferably, the melt spinning of the present invention is completed in a twin-screw extruder.

[0030] As an implementation manner, the first portion of the compound antioxidant in step S3 can be put into the front material port of the extruder; the second portion of the compound antioxidant and the modified cerium oxide in step S4 can be put into the middle material port or the rear material port of the extruder. By utilizing the temperature difference in the extrusion direction of the extruder, the feeding operations of different steps are respectively carried out, realizing continuous production operations.

[0031] Optionally, the lubricant is added to the twin-screw extruder in step S3.

[0032] See Figure 3 , S5, the fiber drawing and cooling stage, the PA6 fiber is subjected to microwave irradiation treatment; microwave frequency: 2.45 GHz; irradiation power: 300 - 500 W; irradiation time: 10 - 20 s; The local heating effect of microwave irradiation promotes the reaction between the amino group (-NH 2 ) of the modified cerium oxide and the carboxyl group (-COOH) at the end of the PA6 molecular chain to form an amide bond (-NH-CO-), realizing the anchoring of the modified cerium oxide, avoiding its migration to the fiber surface, improving the uniformity of the distribution of the modified cerium oxide in the PA6 fiber, and further improving the anti-aging performance of the PA6 fiber.

[0033] The present invention sets multiple groups of process parameters to prepare multiple PA6 fiber specimens as examples.

[0034] At the same time, a conventional melt spinning process is adopted to prepare a comparative example specimen.

[0035] To make the test results comparable, the production parameters of the melt spinning of the example specimens and the comparative example specimens of the present invention are the same (melt temperature, extrusion time, equipment specifications, etc.).

[0036] After each example specimen and comparative example specimen are prepared, the tensile strength is detected. Then all specimens are subjected to artificial aging treatment, and then the tensile strength is tested again, and the tensile strength retention rate after artificial aging is calculated. Specifically: The artificial aging step of the example specimen is: hot oxygen aging at 150 °C for 1000 hours.

[0037] The artificial aging step of the comparative example specimen is: hot oxygen aging at 150 °C for 800 hours.

[0038] The example specimens and comparative example specimens after artificial aging treatment are selected for textile production, and their spinning breakage rates are detected.

[0039] The parameters and test results of each example and comparative example are shown in Table 1 (Note: Only the changed parameters are listed in Table 1. For the same components and steps, please refer to the previous text and will not be elaborated here). Compared with the PA6 fibers without anti-aging treatment, the PA6 fibers treated by the multi-stage cooperative anti-oxidation and anti-aging treatment method of the present application still have a high tensile strength after artificial aging treatment, significantly improving the anti-aging ability of the fibers. Moreover, the surface of the fibers is smooth, the spinning breakage rate is low, and the quality of the textile products is improved.

[0040] Table 1 Parameters and test results of each example and comparative example

[0041] 。

[0042] In summary, the present invention provides an anti-aging composite material, which combines a composite antioxidant and modified cerium oxide, and produces unique antioxidant effects at each oxidation stage of fiber production. The present invention also provides a multi-stage cooperative anti-oxidation and anti-aging treatment method for PA6 fibers, significantly improving the anti-aging ability of the fibers. Moreover, the surface of the fibers is smooth, the spinning breakage rate is low, and the quality of the textile products is improved.

[0043] Certainly, the present invention may also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. An anti-aging composite material, characterized in that: In terms of mass percentage, it includes the following components: PA6 resin: 94-97%; Compound antioxidant: 1.5-3%; Modified cerium oxide: 0.8-2%; Lubricant: 0.5-1%.

2. The anti-aging composite material according to claim 1, characterized in that: The composite antioxidant is a compound of AT-168 and AT-626, and the weight ratio of the two is 2:

1.

3. The anti-aging composite material according to claim 2, characterized in that: The preparation steps of the composite antioxidant are as follows: AT-168 and AT-626 are weighed respectively according to the weight ratio, and then the two are mixed at a rotation speed of 20-30 rpm for 30-40 minutes.

4. The anti-aging composite material according to claim 3, characterized in that: The composite antioxidants AT-168 and AT-626 are dried before mixing; The drying process comprises placing the two in a vacuum drying oven at a temperature of 60±5° C. and a vacuum degree of ≤100 Pa for drying for 4-6 hours.

5. The anti-aging composite material according to claim 1, characterized in that: The preparation steps of the modified cerium oxide include: Weigh a predetermined amount of nano-cerium oxide and a silane coupling agent, the mass ratio of the two being 1: 0.05-0.2; The silane coupling agent is prepared into a 10% concentration solution, and heated to cause a hydrolysis reaction to obtain a hydrolyzed silane coupling agent; Then, nano-cerium oxide is added and heated to produce a coupling reaction to obtain modified cerium oxide; the heating temperature is 120° C. and the reaction time is 30-100 minutes.

6. The anti-aging composite material according to claim 4, characterized in that: The particle size of the nano cerium oxide is no more than 50 nm.

7. The anti-aging composite material according to claim 1, characterized in that: The lubricant is calcium stearate.

8. A PA6 fiber multi-stage synergistic anti-oxidation and aging treatment method, characterized in that: The steps include: S1, preparing the materials of each component according to the mass ratio of the anti-aging composite material according to any one of claims 1 to 7; S2, the composite antioxidant was divided into two equal parts; S3, the initial stage of melt spinning of PA6 resin, the melting temperature is ≤220℃; the first compound antioxidant is added; S4, the final stage of melt spinning of PA6 resin, the melting temperature is 240~260℃; the second portion of composite antioxidant and modified cerium oxide are added; S5, spinning cooling stage, the PA6 fiber is subjected to microwave irradiation treatment; microwave frequency: 2.45 GHz; irradiation power: 300-500 W; irradiation time: 10-20 s.

9. The PA6 fiber multi-stage synergistic anti-oxidation and aging treatment method according to claim 8, characterized in that: The PA6 resin in step S1 is vacuum dried at 100° C. for 4 hours to reduce its moisture content to ≤0.02%.

10. The PA6 fiber multi-stage synergistic anti-oxidation and aging treatment method according to claim 8, characterized in that: The lubricant is added in step S3.

Images