An anti-aging and wear-resistant PE board and its production process

Abstract

The present invention relates to an anti-aging and wear-resistant PE board and its production process, belonging to the technical field of polymer composite materials. The components of the PE board are: 3.6-4.4 wt% of zinc white powder, 0.13-0.18 wt% of modified antioxidant, 1.1-1.4 wt% of lubricant, and 0.7-0.9 wt% of compatibilizer, with the balance being HDPE resin; the modified antioxidant is obtained by transesterification reaction of bromo-n-alkyl alcohol and diethyl thiodiacetate to form a thioester compound containing a bromoalkyl chain, and then etherification reaction of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol with its terminal bromoalkyl group to introduce a terminal hindered phenol structure for modification; the modified antioxidant interacts with zinc white powder, successfully solving the defects of migration and loss of the traditional antioxidant system, interfacial oxidation and poor dispersibility, and realizing the synergistic improvement of anti-aging, wear resistance and mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite materials, and specifically, relates to an anti-aging and wear-resistant PE board and its production process. Background Art

[0002] Polyethylene (PE) boards are widely used in fields such as construction, packaging, automobiles, and logistics due to their advantages of light weight, chemical corrosion resistance, easy processing, and low cost. However, when PE materials are used outdoors or in high-load environments for a long time, they are easily affected by ultraviolet rays, thermal-oxidative aging, and mechanical wear, resulting in significant degradation of mechanical properties, surface powdering and cracking, and deterioration of wear resistance, which seriously restricts their service life. Therefore, the existing technology mainly improves the anti-aging performance of PE boards by adding antioxidant components, but the traditional technology still has the following defects:

[0003] Traditional antioxidant systems mainly use hindered phenol or thioester organic antioxidants to inhibit oxidation reactions by capturing free radicals or decomposing peroxides. However, organic antioxidants have a low molecular weight and poor compatibility with the PE matrix, and are prone to segregation through migration, exudation, etc. during long-term use, resulting in a sharp decline in antioxidant efficiency over time. Moreover, taking the traditional hindered phenol and thioester compound system as an example, it can only partially inhibit different stages of the oxidation chain reaction, but there is a lack of molecular-level synergistic effect between the two, making it difficult to block the diffusion of the chain reaction caused by interfacial oxidation.

[0004] To make up for the deficiencies of organic antioxidants, inorganic light stabilizers are often introduced in the existing technology to delay photoaging by reflecting or scattering ultraviolet rays. Although these inorganic particles can reflect most ultraviolet rays, there will still be multiple reflections and diffuse reflections on their surfaces due to differences in the incident angle of light, especially forming a local light irradiation enhancement area at the particle-matrix interface. The photo-thermal oxidation reaction in this area causes the PE molecular chain to break, generating oxidation products such as carbonyl groups, accelerating interfacial degradation. In addition, the binding ability of these inorganic particles to the PE matrix is not strong, resulting in the shedding of inorganic particles during mechanical friction, forming abrasive wear and exacerbating wear. Summary of the Invention

[0005] In order to solve the technical problems mentioned in the background art, the purpose of the present invention is to provide an anti-aging and wear-resistant PE board and its production process.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An anti-aging and wear-resistant PE board, whose components are: 3.6 - 4.4 wt% of zinc white powder, 0.13 - 0.18 wt% of modified antioxidant, 1.1 - 1.4 wt% of lubricant, and 0.7 - 0.9 wt% of compatibilizer, and the balance is HDPE resin.

[0008] The modified antioxidant is prepared by the following method:

[0009] Step A1: Premix diethyl thiodiacetate, p-toluenesulfonic acid and anhydrous toluene, then add n-alkyl bromoalcohol and mix. Introduce dry nitrogen for protection, heat up to 110 - 120 °C and stir for reflux reaction for 6 - 8 h. After the reaction, remove toluene by distillation under reduced pressure. Cool to room temperature, add saturated sodium bicarbonate solution for washing, remove the aqueous phase and dry under vacuum to obtain the intermediate.

[0010] Furthermore, the feeding ratio of diethyl thiodiacetate, n-alkyl bromoalcohol, p-toluenesulfonic acid and anhydrous toluene is 10 mmol : 22 - 25 mmol : 0.1 - 0.13 g : 60 - 80 mL. Under the acidic catalytic system, n-alkyl bromoalcohol and diethyl thiodiacetate carry out transesterification reaction to form a thioester compound containing a bromoalkyl chain. The reaction route is as follows:

[0011]

[0012] Preferably, the n-alkyl bromoalcohol is one of 8-bromo-1-octanol and 10-bromo-1-decanol.

[0013] Step A2: Dissolve 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, then slowly add sodium hydride and stir at room temperature for 1 - 1.5 h. Then add the intermediate and heat up to 80 - 100 °C and stir for reaction for 3 - 4.5 h. After the reaction, cool and add water for washing, remove the aqueous phase and dry under vacuum to obtain the modified antioxidant.

[0014] Furthermore, the feeding ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is 10 mmol : 20 mmol : 0.15 - 0.2 g : 100 - 150 mL. Under the catalysis of sodium hydride, the intermediate and 3,5-di-tert-butyl-4-hydroxybenzyl alcohol carry out etherification reaction to introduce a terminal hindered phenol structure for modification. The reaction route is as follows:

[0015]

[0016] Preferably, the lubricant is composed of calcium stearate and oxidized polyethylene wax, which synergistically lubricate inside and outside, facilitating the forming of the plate and improving the surface quality of the plate.

[0017] Preferably, the compatibilizer is maleic anhydride grafted polyethylene, which improves the dispersibility of each additive and is beneficial to improving the overall mechanical properties of the plate.

[0018] A production process of an anti-aging and wear-resistant PE plate includes the following processes:

[0019] Process S1: Mix the raw material components of each component. The mixture is plastically extruded, drawn into strips and cooled and pelletized to obtain modified PE pellets.

[0020] Process S2: Soften, extrude, mold and press, and roll and shape the modified PE pellets to obtain an anti-aging and wear-resistant PE board.

[0021] Furthermore, during the plasticizing and extruding process, the plasticizing temperature is 220 ± 5 °C; the softening and extruding temperature is 180 ± 10 °C, and the pressure for molding and pressing is 25 MPa.

[0022] Advantages of the present invention:

[0023] Through molecular structure innovation and interface synergy mechanism, the present invention develops an interaction between a modified antioxidant and zinc white powder, successfully solving the defects of migration and loss, interface oxidation, and poor dispersibility of the traditional antioxidant system, and realizing the synergistic improvement of anti-aging, wear resistance, and mechanical properties; the specific action mechanism is as follows: The thioester group in the modified antioxidant molecule chelates with the zinc ions on the surface of zinc white powder, directly anchors on the surface of zinc white powder, inhibits the generation of peroxides at the UV reflection interface, blocks the starting point of the oxidation chain reaction. Even if a certain amount of peroxides are generated, the hindered phenolic groups at both ends can efficiently scavenge and decompose alkoxy radicals and alkylperoxy radicals, forming stable phenoxy radicals, preventing the diffusion of the chain reaction, thereby forming a dual synergistic antioxidant mechanism to long-term inhibit the oxidation chain reaction; at the same time, due to the chelation binding effect, with zinc white powder as the anchoring matrix, it inhibits the migration and segregation of the modified antioxidant, improves the interfacial binding ability of zinc white powder, forms an interface optimization, improves the mechanical properties of the composite system, and inhibits the shedding and wear of zinc white powder. Specific embodiments

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] Example 1, preparation of an anti-aging and wear-resistant PE board, the implementation process is as follows:

[0026] I. Synthesis of modified antioxidant

[0027] Step A1: Take diethyl thiodiacetate, p-toluenesulfonic acid, and anhydrous toluene, stir and premix, then add 8-bromo-1-octanol and mix, introduce dry nitrogen for protection, heat up to 110 °C, set the stirring rate to 60 r / min, and reflux for 8 h. During the reaction, control the feeding ratio of diethyl thiodiacetate, 8-bromo-1-octanol, p-toluenesulfonic acid, and anhydrous toluene to be 10 mmol: 22 mmol: 0.1 g: 60 mL. After the reaction, distill off toluene under reduced pressure, cool to room temperature, add saturated sodium bicarbonate solution for washing, remove the aqueous phase and dry under vacuum to obtain an intermediate.

[0028] Step A2: Take 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, stir and dissolve them, apply rapid stirring at 120 r / min, slowly add sodium hydride and stir at room temperature for 1.5 hours, then add the intermediate and heat to 80°C, stir and react at 60 r / min for 4.5 hours. During the reaction, the feed ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is controlled to be 10mmol:20mmol:0.15g:100mL. After the reaction is completed and cooled, water is added for mixing, the aqueous phase is removed and vacuum dried to obtain a modified antioxidant.

[0029] 2. Preparation of PE board

[0030] Prepare the materials according to the components: 3.6wt% zinc white powder, commercially available 800 mesh coating powder; 0.13wt% modified antioxidant, homemade in this embodiment; 1.2wt% lubricant, mixed with industrial grade calcium stearate and OP-25 type oxidized polyethylene wax in a mass ratio of 2:1; 0.7wt% compatibilizer, 900E type maleic anhydride grafted polyethylene, and the remainder 5000S type HDPE resin.

[0031] Step S1: Add the raw materials of each component into a high-speed mixer and mix them at a high speed of 600r / min for 15min. The mixed material is sent to an extruder, plasticized and extruded at 220±5℃, and then stretched into strips, cooled and pelletized to obtain modified PE pellets.

[0032] Step S2: Soften and extrude the modified PE pellets at 180±10°C, feed the softened material into a flat die, control the pressure to 25MPa to form a molded plate, and then roll-press to shape, thereby obtaining an anti-aging and wear-resistant PE plate.

[0033] Example 2, preparation of anti-aging and wear-resistant PE board, the implementation process is as follows:

[0034] 1. Synthesis of modified antioxidant

[0035] Step A1: Take diethyl thiodiacetate, p-toluenesulfonic acid and anhydrous toluene and stir to premix, then add 10-bromo-1-decanol and mix, introduce dry nitrogen protection, heat to 120°C, set the stirring rate to 90r / min, reflux reaction for 6h, during the reaction, control the feed ratio of diethyl thiodiacetate, 10-bromo-1-decanol, p-toluenesulfonic acid and anhydrous toluene to be 10mmol:25mmol:0.13g:80mL, after the reaction is completed, evaporate to remove toluene under reduced pressure, cool to room temperature, add saturated sodium bicarbonate solution to wash, remove the aqueous phase and vacuum dry to obtain an intermediate.

[0036] Step A2: Take 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, stir and dissolve them, apply rapid stirring at 150 r / min, slowly add sodium hydride and stir at room temperature for 1 hour, then add the intermediate and heat to 100°C, stir and react at 60 r / min for 3 hours. During the reaction, the feed ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is controlled to be 10mmol:20mmol:0.2g:150mL. After the reaction is completed and cooled, water is added for mixing, the aqueous phase is removed and vacuum dried to obtain a modified antioxidant.

[0037] 2. Preparation of PE board

[0038] Prepare the materials according to the components: 4.4wt% zinc white powder, commercially available 800 mesh coating powder; 0.18wt% modified antioxidant, homemade in this embodiment; 1.4wt% lubricant, mixed with industrial grade calcium stearate and OP-25 type oxidized polyethylene wax in a mass ratio of 2:1; 0.9wt% compatibilizer, 900E type maleic anhydride grafted polyethylene, and the remainder 5000S type HDPE resin.

[0039] Step S1: Add the raw materials of each component into a high-speed mixer and mix them at a high speed of 600r / min for 15min. The mixed material is sent to an extruder, plasticized and extruded at 220±5℃, and then stretched into strips, cooled and pelletized to obtain modified PE pellets.

[0040] Step S2: Soften and extrude the modified PE pellets at 180±10°C, feed the softened material into a flat die, control the pressure to 25MPa to form a molded plate, and then roll-press to shape, thereby obtaining an anti-aging and wear-resistant PE plate.

[0041] Example 3, preparation of anti-aging and wear-resistant PE board, the implementation process is as follows:

[0042] 1. Synthesis of modified antioxidant

[0043] Step A1: Take diethyl thiodiacetate, p-toluenesulfonic acid and anhydrous toluene, stir and premix, then add 8-bromo-1-octanol and mix, introduce dry nitrogen protection, heat to 110°C, set the stirring rate to 60r / min, reflux reaction for 7.5h, during the reaction, control the feed ratio of diethyl thiodiacetate, 8-bromo-1-octanol, p-toluenesulfonic acid and anhydrous toluene to be 10mmol:23mmol:0.11g:65mL, after the reaction is completed, evaporate to remove toluene under reduced pressure, cool to room temperature, add saturated sodium bicarbonate solution to wash, remove the aqueous phase and vacuum dry to obtain an intermediate.

[0044] Step A2: Take 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, stir and dissolve them, apply rapid stirring at 120 r / min, slowly add sodium hydride and stir at room temperature for 1.3 hours, then add the intermediate and heat to 90°C, stir and react at 60 r / min for 4 hours. During the reaction, the feed ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is controlled to be 10mmol:20mmol:0.17g:120mL. After the reaction is completed and cooled, water is added for mixing, the aqueous phase is removed and vacuum dried to obtain a modified antioxidant.

[0045] 2. Preparation of PE board

[0046] Prepare the materials according to the components: 3.9wt% zinc white powder, commercially available 800 mesh coating powder; 0.15wt% modified antioxidant, homemade in this embodiment; 1.1wt% lubricant, mixed with industrial grade calcium stearate and OP-25 type oxidized polyethylene wax in a mass ratio of 2:1; 0.8wt% compatibilizer, 900E type maleic anhydride grafted polyethylene, and the remainder is 5000S type HDPE resin.

[0047] Step S1: Add the raw materials of each component into a high-speed mixer and mix them at a high speed of 600r / min for 15min. The mixed material is sent to an extruder, plasticized and extruded at 220±5℃, and then stretched into strips, cooled and pelletized to obtain modified PE pellets.

[0048] Step S2: Soften and extrude the modified PE pellets at 180±10°C, feed the softened material into a flat die, control the pressure to 25MPa to form a molded plate, and then roll-press to shape, thereby obtaining an anti-aging and wear-resistant PE plate.

[0049] Example 4, preparation of anti-aging and wear-resistant PE board, the implementation process is as follows:

[0050] 1. Synthesis of modified antioxidant

[0051] Step A1: Take diethyl thiodiacetate, p-toluenesulfonic acid and anhydrous toluene and stir to premix, then add 10-bromo-1-decanol and mix, introduce dry nitrogen protection, heat to 120°C, set the stirring rate to 90r / min, reflux reaction for 7h, during the reaction, control the feed ratio of diethyl thiodiacetate, 10-bromo-1-decanol, p-toluenesulfonic acid and anhydrous toluene to be 10mmol:25mmol:0.11g:80mL, after the reaction is completed, evaporate to remove toluene under reduced pressure, cool to room temperature, add saturated sodium bicarbonate solution to wash, remove the aqueous phase and vacuum dry to obtain an intermediate.

[0052] Step A2: Take 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, stir and dissolve them, apply rapid stirring at 150 r / min, slowly add sodium hydride and stir at room temperature for 1.2 hours, then add the intermediate and heat to 90°C, stir and react at 60 r / min for 4 hours. During the reaction, the feed ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is controlled to be 10mmol:20mmol:0.18g:140mL. After the reaction is completed and cooled, water is added for mixing, the aqueous phase is removed and vacuum dried to obtain a modified antioxidant.

[0053] 2. Preparation of PE board

[0054] Prepare the materials according to the components: 4.1wt% zinc white powder, commercially available 800 mesh coating powder; 0.16wt% modified antioxidant, homemade in this embodiment; 1.2wt% lubricant, mixed with industrial grade calcium stearate and OP-25 type oxidized polyethylene wax in a mass ratio of 2:1; 0.7wt% compatibilizer, 900E type maleic anhydride grafted polyethylene, and the remainder 5000S type HDPE resin.

[0055] Step S1: Add the raw materials of each component into a high-speed mixer and mix them at a high speed of 600r / min for 15min. The mixed material is sent to an extruder, plasticized and extruded at 220±5℃, and then stretched into strips, cooled and pelletized to obtain modified PE pellets.

[0056] Step S2: Soften and extrude the modified PE pellets at 180±10°C, feed the softened material into a flat die, control the pressure to 25MPa to form a molded plate, and then roll-press to shape, thereby obtaining an anti-aging and wear-resistant PE plate.

[0057] As a comparative example, referring to Example 4, the modified antioxidant was replaced with 0.1 wt % of antioxidant 1010 and 0.06 wt % of antioxidant 412S, and the rest of the implementation process was exactly the same.

[0058] Samples were taken from the plate prepared as above, and tensile properties were tested according to ASTM D638-22, and wear resistance was tested according to ASTM D4060-19. The specific test results are shown in Table 1:

[0059] Table 1

[0060] Tensile strength / MPa Elongation at break / % Wear / mg Example 1 23.9 352 18.3 Example 2 25.7 315 11.9 Example 3 24.5 339 15.5 Example 4 25.1 357 13.6 Comparative example 24.3 342 14.8

[0061] As can be seen from the test results in Table 1, the above samples all maintain good strength and toughness, and compared with pure PE plates, the wear is no higher than 20 mg, showing a certain wear resistance. From the comparison of the test data of each experiment, it can be seen that as the proportion of zinc white powder component increases, the tensile strength and wear resistance show an upward trend, while the elongation at break decreases. Combining Example 4 and the comparative example, the PE plates prepared by compounding with the existing combination antioxidant have slightly lower strength, toughness and wear resistance.

[0062] Samples were taken from the plates prepared as above, and an accelerated aging test was carried out with reference to the ASTM G155-21 standard. The test cycle was 2000 h. Tensile and wear resistance tests were carried out on the aged specimens according to the above standard, and the change rates of the corresponding performance indicators were calculated. The specific test results are shown in Table 2:

[0063] Table 2

[0064] Change rate of tensile strength / % Change rate of elongation at break / % Change rate of wear / % Example 1 -7.14 -9.11 12.93 Example 2 -4.06 -9.32 14.05 Example 3 -4.82 -5.77 12.19 Example 4 -3.55 -6.08 10.62 Comparative example -10.29 -18.61 31.74

[0065] As can be seen from the test results in Table 2, after the accelerated aging of the plates in the comparative example, the decline in tensile strength and elongation at break is obvious, the wear increases significantly, and a large amount of powder debris can be seen falling off during the test.

[0066] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0067] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of this patent, they should fall within the protection scope of the present invention.

Claims

1. An anti-aging and wear-resistant PE board, characterized in that, The specific components are: 3.6 - 4.4 wt% of zinc white powder, 0.13 - 0.18 wt% of modified antioxidant, 1.1 - 1.4 wt% of lubricant, and 0.7 - 0.9 wt% of compatibilizer, with the balance being HDPE resin; The modified antioxidant is prepared by the following method: Step A1: Premix diethyl thiodiacetate, p-toluenesulfonic acid and anhydrous toluene, then add n-alkyl bromide alcohol and mix, introduce dry nitrogen for protection, heat up to 110 - 120 °C and stir for reflux reaction for 6 - 8 h to obtain an intermediate; Step A2: Mix 3,5-di-tert-butyl-4-hydroxybenzyl alcohol and dimethylformamide, then slowly add sodium hydride and stir at room temperature for 1 - 1.5 h, then add the intermediate and heat up to 80 - 100 °C and stir for reaction for 3 - 4.5 h to obtain the modified antioxidant.

2. The anti-aging and wear-resistant PE board according to claim 1, characterized in that, The feeding ratio of diethyl thiodiacetate, n-alkyl bromide alcohol, p-toluenesulfonic acid and anhydrous toluene is 10 mmol: 22 - 25 mmol: 0.1 - 0.13 g: 60 - 80 mL.

3. The anti-aging and wear-resistant PE board according to claim 2, characterized in that, The n-alkyl bromide alcohol is one of 8-bromo-1-octanol and 10-bromo-1-decanol.

4. The anti-aging and wear-resistant PE board according to claim 2, characterized in that, The feeding ratio of the intermediate, 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, sodium hydride and dimethylformamide is 10 mmol: 20 mmol: 0.15 - 0.2 g: 100 - 150 mL.

5. An anti-aging and wear-resistant PE board according to claim 1, characterized in that The lubricant is composed of calcium stearate and oxidized polyethylene wax.

6. The anti-aging and wear-resistant PE board according to claim 1, characterized in that, The compatibilizer is maleic anhydride grafted polyethylene.

7. A production process of the anti-aging and wear-resistant PE board according to any one of claims 1-6, characterized in that, It includes the following processes: Process S1: Mix the raw materials of each component, and the mixture is plastically extruded, drawn into strips, cooled and pelletized to obtain modified PE pellets; Process S2: Softly extrude the modified PE pellets, press them into plates by die pressing, and roll and shape them to obtain the anti-aging and wear-resistant PE plate.

8. The production process of an anti-aging and wear-resistant PE board according to claim 7, characterized in that, During the plastic extrusion process, the plasticizing temperature is 220 ± 5 °C; the soft extrusion temperature is 180 ± 10 °C, and the die pressing pressure for plate making is 25 MPa.