Preparation method of modified cerium oxide for high toughness and ultraviolet resistant nylon and nylon

Abstract

The application discloses a preparation method of modified cerium oxide for high-toughness and ultraviolet-resistant nylon and the nylon. The preparation method comprises the following steps: S10, adding modified cerium oxide and sodium polycarboxylate into water according to a mass ratio of (9-12):1, and performing first sand grinding to obtain a first solution; S20, uniformly mixing the first solution and octamethylcyclotetrasiloxane according to a mass ratio of (8-10):1, and performing second sand grinding to obtain a second solution; S30, drying the second solution to obtain solid modified cerium oxide; and S40, crushing the solid modified cerium oxide to obtain modified cerium oxide. The sodium polycarboxylate and the octamethylcyclotetrasiloxane are used to modify the cerium oxide, so that the obtained modified cerium oxide is uniformly dispersed when used for preparing the nylon, and meanwhile, the toughness and the ultraviolet resistance of the prepared nylon are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of modified rare earth metal oxide materials, and particularly relates to a preparation method of modified cerium oxide for high-toughness and UV-resistant nylon and the nylon. Background Art

[0002] Nylon is one of the most widely used engineering plastics, widely used in daily life and across various fields. Modification of nylon with inorganic materials is common on the market, but modification with rare earth materials is less common. Cerium oxide, a rare earth material, has been shown to absorb light of varying wavelengths, from ultraviolet to visible light, within a narrow wavelength range. This makes it suitable for applications such as protecting polymers from UV aging. Therefore, the addition of cerium oxide to nylon could improve its UV resistance and hold great market potential. However, the direct addition of cerium oxide reduces the nylon's toughness, failing to achieve the desired effect. Therefore, the key challenge currently remains in finding a way to simultaneously enhance the UV resistance and toughness of nylon treated with cerium oxide.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a method for preparing modified cerium oxide for high-toughness and UV-resistant nylon and nylon. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a method for preparing modified cerium oxide for high-toughness and UV-resistant nylon, comprising the following steps:

[0006] S10, adding the unmodified cerium oxide and sodium polycarboxylate to water in a mass ratio of (9-12):1, and performing a first sand milling to obtain a first solution; wherein, after the first sand milling, the cerium oxide particle size in the first solution satisfies D100 less than 1 μm;

[0007] S20, mixing the first solution and octamethylcyclotetrasiloxane in a mass ratio of (8-10):1, and performing a second sand milling to obtain a second solution; wherein after the second sand milling, the particle size of the modified cerium oxide in the second solution satisfies D50 of 10 μm to 20 μm;

[0008] S30, drying the second solution to obtain solid-state modified cerium oxide;

[0009] S40, crushing the solid-state modified cerium oxide to obtain modified cerium oxide.

[0010] In one embodiment of the present invention, step S20 includes: mixing the first solution and octamethylcyclotetrasiloxane in a mass ratio of (8-10):1, adding sodium polyacrylate, mixing again, and performing a second sand milling to obtain the second solution;

[0011] The added mass of the sodium polyacrylate is 2% to 4% of the mass of the first solution.

[0012] In one embodiment of the present invention, in step S20, performing a second sanding to obtain a second solution includes:

[0013] Sand milling is performed at a rotation speed of 1500 rpm to 3000 rpm using zirconium oxide beads with a particle size of 0.3 mm to 0.5 mm as a grinding medium. Sampling is performed at preset intervals to detect the particle size of the modified cerium oxide until the particle sizes of two adjacent modified cerium oxides are the same. Then, sand milling is stopped to obtain the second solution.

[0014] In one embodiment of the present invention, in step S10, the mass of the water is 9 to 11 times the mass of the cerium oxide before modification.

[0015] In one embodiment of the present invention, in step S10, the first sanding comprises: sanding at a rotation speed of 2500 rpm to 4000 rpm using zirconium oxide beads with a particle size of 0.1 mm to 0.3 mm as a grinding medium so that the cerium oxide satisfies D100 less than 1 μm.

[0016] In one embodiment of the present invention, in step S30, the drying is performed by spray drying;

[0017] The spray drying adopts a spray drying system, the operating power frequency range of the fan of the spray drying system is 45Hz-60Hz, the inlet air temperature is 200℃-220℃; the speed of the feed peristaltic pump of the spray drying system is 20rpm-25rpm.

[0018] In one embodiment of the present invention, in step S40, the pulverization is performed by air flow pulverization;

[0019] The air flow pulverization adopts an air flow pulverization system. The gas used in the air flow pulverization system is dehydrated and deoiled compressed air. The gas pressure is 1.0MPa to 1.2MPa. The feed rate of the air flow pulverization system is 90g / min to 100g / min.

[0020] In a second aspect, the present invention provides a nylon comprising a nylon resin and modified cerium oxide prepared by the above-mentioned preparation method; wherein the mass content of the modified cerium oxide is 0.1% to 2%.

[0021] In one embodiment of the present invention, the nylon is prepared by a masterbatch method;

[0022] The masterbatch method comprises: mixing the modified cerium oxide and the nylon resin in a mass ratio of 1:9 to prepare a masterbatch;

[0023] The masterbatch and the nylon resin are then mixed and heated in a mass ratio of 1:(1-20) to prepare the nylon.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1, the preparation method of the modified cerium oxide for high toughness and anti-ultraviolet nylon provided by the present invention, first adopt sodium polycarboxylate and cerium oxide before modification to mix, then add octamethylcyclotetrasiloxane and realize the modification of cerium oxide.On the one hand, the anion layer of sodium polycarboxylate provides electrostatic repulsion, and the hydrophobic layer of octamethylcyclotetrasiloxane reduces water molecule infiltration, and both cooperate to suppress the reunion of cerium oxide particles in different media (aqueous phase / organic phase).On the other hand, the hydrophilic segment of sodium polycarboxylate can maintain the dispersibility of cerium oxide particles in aqueous phase, the hydrophobization of octamethylcyclotetrasiloxane can reduce the interfacial energy of cerium oxide particles and organic phase, sodium polycarboxylate and octamethylcyclotetrasiloxane make good dispersibility in the cerium oxide modification process by " hydrophilic-hydrophobic microregion ", also be conducive to the cerium oxide after modification when being used to prepare nylon, more evenly dispersed in nylon resin, can again with polymer (nylon resin) good compatibility, improve the performance of prepared nylon.

[0026] 2. Flexible Si-O-Si segments are introduced into the modified cerium oxide obtained by the preparation method provided by the present invention, and the Si-O bonds are relatively long, so that the nylon material prepared using the modified cerium oxide can absorb energy through the movement of the segments when subjected to force, thereby improving the toughness of the nylon material; at the same time, the electronic transition energy level of the Si-O bond is relatively high, and can absorb ultraviolet rays (especially ultraviolet rays with a wavelength of 200nm to 280nm), which can reduce the degradation of nylon matrix materials such as nylon resin by ultraviolet rays, and the Si-O bond has a high bond energy and is difficult to be broken by ultraviolet light, thereby improving the durability of nylon.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the scanning electron microscope characterization of cerium oxide before modification;

[0029] Figure 2 is a scanning electron microscope characterization image of cerium oxide after the first sanding in Example 1 of the present invention;

[0030] Figure 3is a scanning electron microscope characterization image of the modified cerium oxide prepared in Example 1 of the present invention;

[0031] Figure 4 is a scanning electron microscope characterization image of the modified cerium oxide prepared in Example 2 of the present invention;

[0032] Figure 5 is a scanning electron microscope characterization image of the modified cerium oxide prepared in Example 3 of the present invention;

[0033] Figure 6 This is a scanning electron microscope characterization image of the modified cerium oxide prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0034] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of a preparation method of modified cerium oxide for high-toughness and UV-resistant nylon and nylon proposed in accordance with the present invention, in combination with the accompanying drawings and specific implementation methods.

[0035] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of those features. Furthermore, the terms "comprises," "comprising," or any other variations are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not explicitly listed.

[0037] An embodiment of the present invention provides a method for preparing modified cerium oxide for high-toughness and UV-resistant nylon, comprising steps S10 to S40.

[0038] S10. Adding the unmodified cerium oxide and sodium polycarboxylate to water in a mass ratio of (9-12):1, performing a first sand milling to obtain a first solution; wherein, after the first sand milling, the particle size of the cerium oxide in the first solution satisfies D100 less than 1 μm.

[0039] S20, the first solution is mixed with octamethylcyclotetrasiloxane according to a mass ratio (8-10):1, and then second sanding is performed to obtain a second solution; wherein the particle size of the modified cerium oxide in the second solution after the second sanding satisfies D50 of 10-20 μm.

[0040] S30, the second solution is dried to obtain solid modified cerium oxide.

[0041] S40, the solid modified cerium oxide is crushed to obtain modified cerium oxide.

[0042] In the preparation method of the modified cerium oxide provided by the application, sodium polycarboxylate (PAAS) is first mixed with unmodified cerium oxide, and then octamethylcyclotetrasiloxane (D4) is added to modify the cerium oxide. - Na + The -COO - in the sodium polycarboxylate can be preferentially adsorbed on the surface of the cerium oxide particles through ionic bonds or hydrogen bonds, and at the same time, the long carbon chain structure on the surface of the cerium oxide particles forms an extended hydration layer, which prevents particle agglomeration through steric exclusion and improves the dispersibility of the unmodified cerium oxide particles.

[0043] That is, the sodium polycarboxylate occupies the high-polarity sites on the surface of the cerium oxide particles through strong electrostatic / hydrogen bonding, forcing the octamethylcyclotetrasiloxane to mainly react with the non-polar regions or the remaining small amount of -OH, thereby avoiding excessive aggregation of the hydrophobic layer and forming a more uniform “hydrophilic-hydrophobic microregion” structure.

[0044] The preparation method provided in the embodiment of the present invention introduces a flexible Si-O-Si segment in modified cerium oxide by octamethylcyclotetrasiloxane, and the Si-O bond is longer, so that the nylon material prepared by modified cerium oxide can absorb energy by segment motion when subjected to force, thereby improving the toughness of the nylon material. At the same time, the electronic transition energy level of the Si-O bond is higher, and it can absorb part of the ultraviolet light (especially the ultraviolet light UV wavelength is 200nm~280nm), which can reduce the degradation of nylon matrix materials such as nylon resin by ultraviolet rays, and the bond energy of the Si-O bond is high, which is more difficult to be broken by ultraviolet light, thereby improving the durability of nylon. In this way, by modifying cerium oxide with octamethylcyclotetrasiloxane, the anti-ultraviolet performance and toughness of nylon can be improved simultaneously, so that the mechanical properties, light resistance and service life of the nylon obtained are greatly improved.

[0045] In the present invention, the mass ratio of pre-modified cerium oxide to sodium polycarboxylate is (9-12):1. Within this mass range, sodium polycarboxylate can form a hydrophilic bonding layer of appropriate density on the surface of the pre-modified cerium oxide particles, facilitating the formation of an amphiphilic surface structure in conjunction with the subsequently added octamethylcyclotetrasiloxane. If the amount of sodium polycarboxylate is too small, the pre-modified cerium oxide cannot be effectively and stably dispersed in water. If the amount of sodium polycarboxylate is too large, on the one hand, excessive sodium polycarboxylate will occupy too many reactive sites on the surface of the cerium oxide particles, and excessive steric hindrance will make it difficult for the subsequently added octamethylcyclotetrasiloxane to bind to the surface of the cerium oxide particles. On the other hand, it will also lead to increased liquid viscosity, affecting the fluidity of the aqueous solution, reducing the dispersibility of the pre-modified cerium oxide, and increasing the risk of aggregation of the pre-modified cerium oxide particles. For example, the mass ratio of pre-modified cerium oxide to sodium polycarboxylate can be 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, or 12:1, etc.

[0046] In the present invention, the mass ratio of the first solution to octamethylcyclotetrasiloxane is (8-10):1. If the amount of octamethylcyclotetrasiloxane used is too small, the surface of the cerium oxide particles cannot be effectively covered, resulting in incomplete modification and easily causing performance defects. For example, the octamethylcyclotetrasiloxane cannot effectively bind to the reactive sites on the surface of the cerium oxide particles, resulting in a weak covalent Si-O-Si bond. This can easily fall off under mechanical shear and other forces during the preparation of nylon doped with modified cerium oxide, reducing the toughness of the nylon and affecting the interfacial bonding between the modified cerium oxide particles and the nylon matrix. If the amount of octamethylcyclotetrasiloxane used is too large, the excess octamethylcyclotetrasiloxane may cover the carboxylate sites of the sodium polycarboxylate, reducing the dispersibility and stability of the cerium oxide particles. It may also increase the risk of side reactions, such as self-polymerization of octamethylcyclotetrasiloxane to form oligomers. For example, the mass ratio of the first solution to octamethylcyclotetrasiloxane can be 8:1, 8.5:1, 9:1, 9.5:1, or 10:1.

[0047] Furthermore, the mass ratio of cerium oxide to sodium polycarboxylate before modification is 10:1, and the mass ratio of the first solution to octamethylcyclotetrasiloxane is 10:1. At this ratio, the sodium polycarboxylate and octamethylcyclotetrasiloxane exhibit a more synergistic effect, allowing the cerium oxide particles to be evenly dispersed in the aqueous solution, improving the uniformity of the particle size of the prepared modified cerium oxide. Furthermore, when the prepared modified cerium oxide is used to prepare nylon, it has high dispersibility in the nylon matrix and excellent interfacial bonding with the nylon matrix, which can improve the toughness and UV resistance of the prepared material.

[0048] In one example, in step S10, the mass of water is 9 to 11 times the mass of the cerium oxide before modification. This is because too little water can easily lead to uneven dispersion of the cerium oxide before modification, resulting in poor modification effect; too much water can result in too low a concentration of the cerium oxide before modification, and excessive water can increase subsequent drying time. Long periods of high-temperature drying can easily lead to thermal damage to the modified cerium oxide particles.

[0049] In one example, in step S10, zirconia (ZrO2) beads with a particle size of 0.1 mm to 0.3 mm are used as grinding media at a rotation speed of 2500 rpm to 4000 rpm, and sand-milling is performed so that cerium oxide satisfies D100 less than 1 μm.

[0050] In one embodiment of the present invention, step S20 includes: uniformly mixing the first solution with octamethylcyclotetrasiloxane in a mass ratio of (8-10):1, adding sodium polyacrylate, mixing again, and performing a second sand milling to obtain a second solution. After the second sand milling, the modified cerium oxide particles in the second solution meet the D50 of 10μm to 20μm. The added mass of sodium polyacrylate is 2% to 4% of the mass of the first solution. The hydrophobic layer formed by octamethylcyclotetrasiloxane may have gaps due to steric hindrance. In this embodiment, by adding sodium polyacrylate with linear chains, the linear chains fill these gaps, preventing water penetration and further suppressing the aggregation of the modified cerium oxide particles during high-temperature processing during the preparation of nylon, thereby improving the dispersion uniformity of the modified cerium oxide particles and making the prepared nylon have better toughness and UV resistance. For example, the added mass of sodium polyacrylate can be 2%, 2.5%, 3%, 3.5%, or 4% of the mass of the first solution.

[0051] In one example, in step S20, a second sand milling is performed to obtain a second solution, which includes: sand milling at a rotation speed of 1500rpm to 3000rpm and using zirconium oxide beads with a particle size of 0.3mm to 0.5mm as a grinding medium, sampling and detecting the particle size of the modified cerium oxide at preset intervals until the particle sizes of the modified cerium oxide are the same for two adjacent times, stopping sand milling, and obtaining the second solution.

[0052] In one example, in step S30, drying is performed by spray drying. In the spray drying system, the operating power frequency range of the fan is 45 Hz to 60 Hz, the inlet air temperature is 200° C. to 220° C., and the speed of the feed peristaltic pump of the spray drying system is 20 rpm to 25 rpm.

[0053] In one example, in step S40, the pulverization is performed by air flow pulverization. In the air flow pulverization system, the gas used is dehydrated and deoiled compressed air, the gas pressure is 1.0 MPa to 1.2 MPa, and the feed rate of the air flow pulverization system is 90 g / min to 100 g / min.

[0054] An embodiment of the present invention further provides a nylon comprising a nylon resin and modified cerium oxide prepared by the preparation method disclosed in any one of the above embodiments.

[0055] In one example, the mass content of the modified cerium oxide is 0.1% to 2%. For example, in the above-mentioned nylon, the mass content of the modified cerium oxide can be 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, 1.8% or 2%.

[0056] In one example, nylon is prepared using a masterbatch method. Specifically, the masterbatch method includes:

[0057] The modified cerium oxide and nylon resin were mixed in a mass ratio of 1:9 to prepare a masterbatch;

[0058] The masterbatch is then mixed with nylon resin in a mass ratio of 1:(1-20) and heated to prepare nylon.

[0059] The preparation method of the modified cerium oxide provided by the present invention and the performance of nylon doped with the modified cerium oxide are further described below with reference to specific examples.

[0060] Example 1

[0061] S10, adding 100g of pre-modified cerium oxide and 10g of sodium polycarboxylate to 1000g of water, and then sand-milling the mixed aqueous solution of pre-modified cerium oxide and sodium polycarboxylate for the first time at a speed of 3000rpm using zirconium oxide beads with a particle size of 0.3mm to 0.4mm, so that the particle size of cerium oxide satisfies D100 less than 1μm (measured particle size, the particles contain multiple original crystals), to obtain a first solution. Figure 2 As shown in the figure, it is the scanning electron microscope (SEM) characterization picture of cerium oxide after the first sanding, which is similar to the Figure 1Compared with the SEM characterization image of cerium oxide before modification without sand grinding, the cerium oxide particles after sand grinding are more uniformly spherical (the original crystal particle size of cerium oxide is marked in the characterization image; among them, L1=23.37nm, L2=22.35nm, L3=25.45nm, L4=20.08nm, L5=37.36nm) and have better dispersion.

[0062] S20, taking 100g of the first solution and 10g of octamethylcyclotetrasiloxane, mixing them evenly, adding 2g of sodium polyacrylate and mixing evenly. Then, sand milling the mixture for a second time at a speed of 2000rpm using zirconium oxide beads with a particle size of 0.3mm to 0.5mm. During the sand milling process, the particle size was measured every 2 minutes. When the particle size of the modified cerium oxide was the same in two adjacent steps, sand milling was stopped to obtain a second solution.

[0063] S30: spray drying the second solution to obtain solid modified cerium oxide. The spray drying is performed using a spray drying system, wherein the operating power supply frequency range of the spray drying system fan is 45 Hz to 60 Hz, the inlet air temperature is 200° C. to 220° C., and the speed of the feed peristaltic pump of the spray drying system is 20 rpm to 25 rpm.

[0064] S40. The solid modified cerium oxide is subjected to air flow milling. The air flow milling adopts an air flow milling system. The air flow milling system uses dehydrated and deoiled compressed air with a gas pressure of 1.0 MPa to 1.2 MPa. The air flow milling system feeds a material at a rate of 90 g / min to 100 g / min. The modified cerium oxide after the air flow milling has a particle size D50 of less than 1 μm (measured particle size), thereby obtaining a modified cerium oxide powder. Steps S10 to S40 in Example 1 are repeated multiple times to obtain multiple batches of modified cerium oxide powder, and the obtained modified cerium oxide powder is defined as modified cerium oxide 1.

[0065] The prepared modified cerium oxide 1 was detected by scanning electron microscopy, and the obtained characterization diagram is as follows: Figure 3 As shown, the modified cerium oxide particles are uniformly spherical.

[0066] Example 2

[0067] The difference between Example 2 and Example 1 is that in step S10, 90 g of pre-modified cerium oxide and 10 g of sodium polycarboxylate are added to 1100 g of water; in step S20, 80 g of the first solution and 10 g of octamethylcyclotetrasiloxane are mixed uniformly, and then 2.4 g of sodium polyacrylate is added and mixed uniformly.

[0068] The remaining steps are the same as those in Example 1. The modified cerium oxide powder prepared is defined as modified cerium oxide 2. The characterization image of modified cerium oxide 2 obtained by scanning electron microscopy is shown in FIG. Figure 4 shown.

[0069] Example 3

[0070] The difference between Example 3 and Example 1 is that in step S10, 110 g of unmodified cerium oxide and 10 g of sodium polycarboxylate are added to 990 g of water; in step S20, 100 g of the first solution and 10 g of octamethylcyclotetrasiloxane are mixed uniformly, and then 4 g of sodium polyacrylate is added and mixed uniformly.

[0071] The remaining steps are the same as those in Example 1. The modified cerium oxide powder prepared is defined as modified cerium oxide 3. The characterization image of modified cerium oxide 3 obtained by scanning electron microscopy is shown in FIG. Figure 5 shown.

[0072] Example 4

[0073] The difference between Example 4 and Example 1 is that in step S10, 120 g of pre-modified cerium oxide and 10 g of sodium polycarboxylate are added to 1200 g of water; in step S20, 90 g of the first solution and 10 g of octamethylcyclotetrasiloxane are mixed uniformly, and then 2.7 g of sodium polyacrylate is added and mixed uniformly.

[0074] The remaining steps are the same as those in Example 1. The modified cerium oxide powder prepared is defined as modified cerium oxide 4. The characterization diagram of modified cerium oxide 4 obtained by scanning electron microscopy is shown in FIG. Figure 6 .

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 1 is that in step S10, 140 g of pre-modified cerium oxide and 10 g of sodium polycarboxylate are added to 1400 g of water. The remaining steps are the same as in Example 1. The prepared modified cerium oxide powder is defined as modified cerium oxide 5.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 1 is that in step S10, 80 g of pre-modified cerium oxide and 10 g of sodium polycarboxylate are added to 800 g of water. The remaining steps are the same as in Example 1, and the prepared modified cerium oxide powder is defined as modified cerium oxide 6.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 3 and Example 1 is that in step S20, 120 g of the first solution and 10 g of octamethylcyclotetrasiloxane are mixed. The remaining steps are the same as in Example 1, and the prepared modified cerium oxide powder is defined as modified cerium oxide 7.

[0081] Comparative Example 4

[0082] Comparative Example 4 differs from Example 1 in that 60 g of the first solution and 10 g of octamethylcyclotetrasiloxane are mixed in step S20. The remaining steps are the same as in Example 1, and the modified cerium oxide powder obtained is defined as modified cerium oxide 8.

[0083] Example 5

[0084] A nylon is prepared by mixing the modified cerium oxide 1 prepared in Example 1 with a nylon resin, specifically including:

[0085] Step 1: 20 g of the modified cerium oxide is mixed with 180 g of a nylon resin (PA) and heated, the heating temperature is 270°C, and the mixture is extruded through an extruder; at the same time, the extruded material is solidified after the external temperature is reduced, and the length of the master batch particles is 3 mm.

[0086] Step 2: 150 g of the master batch particles are mixed with 1350 g of a nylon resin (PA) and heated, the heating temperature is 270°C, and the mixture is heated to a viscous liquid, and then passed through a drawing machine, a 1400-mesh screen is installed at the pump head to simulate the drawing state, and a nylon filament is obtained, which is defined as nylon filament 1. The change in the pre-pump pressure during the preparation of the nylon filament 1 is observed, and the monitoring data are shown in Table 1.

[0087] Table 1. Change in pre-pump pressure with time during preparation of nylon filament 1

[0088]

[0089] Example 6

[0090] Example 6 differs from Example 5 in that 15 g of the master batch particles are mixed with 1485 g of a nylon resin (PA) in step 2.

[0091] The remaining operations are the same as in Example 5, and a nylon filament is obtained, which is defined as nylon filament 2. The change in the pre-pump pressure during the preparation of the nylon filament 2 is observed, and the monitoring data are shown in Table 2.

[0092] Table 2. Change in pre-pump pressure with time during preparation of nylon filament 2

[0093]

[0094] Example 7

[0095] Example 7 differs from Example 5 in that 75 g of the master batch particles are mixed with 1425 g of a nylon resin (PA) in step 2.

[0096] The remaining operations are the same as in Example 5, and a nylon filament is obtained, which is defined as nylon filament 3. The change in the pre-pump pressure during the preparation of the nylon filament 3 is observed, and the monitoring data are shown in Table 3.

[0097] Table 3. Changes of pump pressure over time during the preparation of nylon yarn 3

[0098]

[0099] Example 8

[0100] The difference between Example 8 and Example 5 is that in step 2, 225 g of masterbatch particles are mixed with 1275 g of nylon resin (PA).

[0101] The remaining operations were the same as those in Example 5, and the obtained nylon yarn was defined as nylon yarn 4. The changes in the pump front pressure during the preparation of nylon yarn 4 were observed, and the monitoring data are shown in Table 4.

[0102] Table 4. Changes of pump pressure over time during the preparation of nylon yarn 4

[0103]

[0104] Example 9

[0105] The difference between Example 9 and Example 5 is that in step 2, 300 g of masterbatch particles are mixed with 1200 g of nylon resin (PA).

[0106] The remaining operations were the same as those in Example 5, and the obtained nylon yarn was defined as nylon yarn 5. The changes in the pump front pressure during the preparation of nylon yarn 5 were observed, and the monitoring data are shown in Table 5.

[0107] Table 5. Changes of pump pressure over time during the preparation of nylon yarn 5

[0108]

[0109] Comparative Example 5

[0110] Nylon is prepared by mixing cerium oxide (particle size D50 is 10 μm to 20 μm) before modification with nylon resin, specifically including:

[0111] Step 1: Take 20g of cerium oxide before modification and mix it evenly with 180g of nylon resin (PA), heat the mixture to 270°C, and extrude it through an extruder; while it is being extruded, the external temperature is lowered, and the liquid material is solidified and cut to form masterbatch particles with a length of 3mm.

[0112] Step 2: 150g of the masterbatch pellets were mixed with 1350g of nylon resin (PA) and heated at 270°C until a viscous liquid slurry formed. The slurry was then passed through a wire drawing machine with a 1400-mesh screen installed at the pump head to simulate the wire drawing process. The resulting nylon yarn was defined as nylon 6. The changes in the pump pressure during the preparation of nylon 6 were observed, and the monitoring data are shown in Table 6.

[0113] Table 6. Changes of pump pressure over time during the preparation of nylon 6

[0114]

[0115] Comparative Example 6

[0116] The modified cerium oxide 5 prepared in Comparative Example 1 was used to prepare a nylon yarn, which was defined as nylon yarn 7, through the same process as in Example 5. The changes in the pre-pump pressure during the preparation of nylon yarn 7 were observed, and the monitoring data are shown in Table 7.

[0117] Table 7. Changes in pump pressure over time during the preparation of nylon yarn 7

[0118]

[0119] Comparative Example 7

[0120] The modified cerium oxide 6 prepared in Comparative Example 2 was used in the same process as in Example 5 to prepare a nylon yarn defined as nylon yarn 8. The changes in the pump front pressure during the preparation of nylon yarn 8 were observed, and the monitoring data are shown in Table 8.

[0121] Table 8. Changes of pump pressure over time during the preparation of nylon yarn 8

[0122]

[0123] Comparative Example 8

[0124] The modified cerium oxide 7 prepared in Comparative Example 3 was used to prepare a nylon yarn, which was defined as nylon yarn 9, through the same process as in Example 5. The changes in the pump front pressure during the preparation of nylon yarn 9 were observed, and the monitoring data are shown in Table 9.

[0125] Table 9. Changes in pump pressure over time during the preparation of nylon yarn 9

[0126]

[0127] Comparative Example 9

[0128] Using the modified cerium oxide 8 prepared in Comparative Example 4, the nylon yarn prepared by the same process as in Example 5 was defined as nylon yarn 10. The changes in the pump front pressure during the preparation of nylon yarn 10 were observed, and the monitoring data are shown in Table 10.

[0129] Table 10. Changes of pump pressure over time during the preparation of nylon yarn 10

[0130]

[0131] Combined with the experimental results of Examples 1 to 4, it is shown that spherical modified cerium oxide with uniform particle size can be prepared within the parameter range disclosed in the present invention.

[0132] Examples 5 to 8 are nylons prepared using modified cerium oxide. Under a high-density screen of 1400 mesh (aperture of about 10 μm), the nylon drawing state is simulated, and the change in the pump-front pressure corresponding to each nylon yarn over time is monitored. Compared with Comparative Example 5 (doped with unmodified ordinary cerium oxide), within the monitoring time range of 30 minutes, the change in the pump-front pressure of the nylon doped with modified cerium oxide is small, indicating that the addition of modified cerium oxide can greatly improve the toughness of the nylon yarn. In Comparative Example 5, the pump-front pressure increases sharply at 10 minutes, indicating that there are breakages and blockages during the drawing process, resulting in increased pressure. In addition, comparing the pump-front pressure monitoring results of Example 6 with that of Comparative Example 5, even if the doping amount of modified cerium oxide in nylon is as low as 0.1%, the pump-front pressure remains relatively stable for 30 minutes, which can also effectively improve the toughness of nylon.

[0133] Compared with Example 5, the pump pressure increased during the preparation of nylon filament using the modified cerium oxide 5 obtained in Comparative Example 1 in Comparative Example 6. This is because the amount of sodium polycarboxylate used in the preparation of modified cerium oxide 5 was reduced, resulting in uneven dispersion of the cerium oxide before modification, which in turn prevented effective coverage with octamethylcyclotetrasiloxane and resulted in insufficient modification.

[0134] Compared with Example 5, in Comparative Example 7, the pump pressure increased during the preparation of nylon filaments using the modified cerium oxide 6 obtained in Comparative Example 2. This is because the excessive amount of sodium polycarboxylate used in the preparation of modified cerium oxide 6 increased the viscosity of the aqueous solution of the pre-modified cerium oxide, which was not conducive to the dispersion of the pre-modified cerium oxide particles. At the same time, the sodium polycarboxylate occupied a large area on the surface of the pre-modified cerium oxide particles, forming a large steric hindrance, which affected the binding of octamethylcyclotetrasiloxane with the pre-modified cerium oxide particles, reduced the modification effect, and thus reduced the toughness of the prepared nylon.

[0135] Compared with Example 5, in Comparative Example 8, the pump pressure increased during the preparation of nylon yarn using the modified cerium oxide 7 obtained in Comparative Example 3. This is because the amount of octamethylcyclotetrasiloxane used in the preparation of modified cerium oxide 7 was relatively small, resulting in incomplete modification and performance defects, which affected the properties of the prepared nylon.

[0136] Compared with Example 5, the pump pressure increased during the preparation of nylon filaments using the modified cerium oxide 8 obtained in Comparative Example 9. This is because the excessive amount of octamethylcyclotetrasiloxane used in the preparation of modified cerium oxide 8 may affect the formation of the amphiphilic surface structure and thus the dispersibility of the modified cerium oxide in the nylon resin.

[0137] The above is further detailed description of the present application in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, and all of them shall be deemed as falling within the protection scope of the present application.

Claims

1. A method for preparing modified cerium oxide for high-toughness and UV-resistant nylon, characterized in that: The following steps are involved: S10, adding the unmodified cerium oxide and sodium polycarboxylate to water in a mass ratio of (9-12):1, and performing a first sand milling to obtain a first solution; wherein, after the first sand milling, the cerium oxide particle size in the first solution satisfies D100 less than 1 μm; S20, mixing the first solution and octamethylcyclotetrasiloxane in a mass ratio of (8-10):1, and performing a second sand milling to obtain a second solution; wherein after the second sand milling, the particle size of the modified cerium oxide in the second solution satisfies D50 of 10 μm to 20 μm; S30, drying the second solution to obtain solid-state modified cerium oxide; S40, crushing the solid-state modified cerium oxide to obtain modified cerium oxide.

2. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to claim 1, characterized in that: Step S20 includes: mixing the first solution and octamethylcyclotetrasiloxane in a mass ratio of (8-10):1, adding sodium polyacrylate, mixing again, and performing a second sand milling to obtain the second solution; The added mass of the sodium polyacrylate is 2% to 4% of the mass of the first solution.

3. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to claim 2, characterized in that: In step S20, performing a second sand grinding to obtain a second solution includes: Sand milling is performed at a rotation speed of 1500 rpm to 3000 rpm using zirconium oxide beads with a particle size of 0.3 mm to 0.5 mm as a grinding medium. Sampling is performed at preset intervals to detect the particle size of the modified cerium oxide until the particle sizes of two adjacent modified cerium oxides are the same. Then, sand milling is stopped to obtain the second solution.

4. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to claim 1, characterized in that: In step S10, the mass of the water is 9 to 11 times the mass of the cerium oxide before modification.

5. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to claim 4, characterized in that: In step S10 , the first sanding includes sanding until the cerium oxide particle size satisfies D100 less than 1 μm at a rotation speed of 2500 rpm to 4000 rpm and using zirconium oxide beads with a particle size of 0.1 mm to 0.3 mm as a grinding medium.

6. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to any one of claims 1 to 5, characterized in that: In step S30, the drying is performed by spray drying; The spray drying adopts a spray drying system, the operating power frequency range of the fan of the spray drying system is 45Hz-60Hz, the inlet air temperature is 200℃-220℃; the speed of the feed peristaltic pump of the spray drying system is 20rpm-25rpm.

7. The method for preparing modified cerium oxide for high-toughness and UV-resistant nylon according to any one of claims 1 to 5, characterized in that: In step S40, the pulverization is performed by air flow pulverization; The air flow pulverization adopts an air flow pulverization system. The gas used in the air flow pulverization system is dehydrated and deoiled compressed air. The pressure of the gas is 1.0MPa to 1.2MPa. The feed rate of the air flow pulverization system is 90g / min to 100g / min.

8. A nylon, characterized in that: The invention comprises nylon resin and modified cerium oxide prepared by the preparation method according to any one of claims 1 to 7; wherein the mass content of the modified cerium oxide is 0.1% to 2%.

9. The nylon according to claim 8, characterized in that The nylon is prepared by a masterbatch method; The masterbatch method comprises: mixing the modified cerium oxide and the nylon resin in a mass ratio of 1:9 to prepare a masterbatch; The masterbatch and the nylon resin are then mixed and heated in a mass ratio of 1:(1-20) to prepare the nylon.

Images