Ultraviolet resistant heat-insulating polypropylene material and preparation method thereof

Abstract

The application discloses an anti-ultraviolet heat-insulating polypropylene material and a preparation method thereof, and relates to the technical field of high-performance polypropylene, which comprises the following components: 65-85 parts of polypropylene resin, 5-20 parts of a compatilizer, 3-30 parts of a filler, and 0-5.0 parts of an auxiliary agent; the filler is composed of hollow glass beads with low thermal conductivity and mica powder with sheet layer barrier capacity, and the filler is surface-modified; the anti-ultraviolet compound is chemically bonded to the surface of the filler through Zn-Ti co-deposition and PDA-mediated grafting reaction, the polarity of the filler is improved, the dispersibility of the filler in the polypropylene resin is improved, the interfacial bonding force between the polypropylene is improved, the stress concentration is reduced, the tensile strength and impact toughness of the material are improved, and the overall mechanical property is enhanced; the modified filler can effectively absorb UVB / UVA, the hydroxyl phenyl structure of the modified filler can effectively quench free radicals, and the ultraviolet shielding property of the modified filler and the polypropylene material is improved.

Description

Technical Field

[0001] This invention relates to the field of high-performance polypropylene technology, specifically to an anti-ultraviolet heat-insulating polypropylene material and its preparation method. Background Technology

[0002] Polypropylene resin is widely used in packaging and other fields due to its abundant monomer sources, excellent mechanical properties, outstanding chemical stability, good processing performance, and low price. However, in practical applications, polypropylene materials are often exposed to solar radiation. Ultraviolet radiation, the highest energy form of solar radiation, is often accompanied by thermal radiation. When the temperature rises, thermal degradation and photodegradation occur simultaneously, accelerating the degradation process of the material. Because the chemical bond energy of polypropylene highly overlaps with the energy of ultraviolet radiation, its chemical bonds become extremely fragile under ultraviolet light. Atoms automatically absorb ultraviolet energy, transitioning from the ground state to an unstable excited state, leading to molecular chain breakage and triggering a series of physicochemical changes.

[0003] In industrial production, a common method to improve the UV aging resistance of polypropylene is to add additives such as antioxidants and UV stabilizers. These additives can effectively consume various unstable free radicals generated during the aging process of polypropylene, thereby slowing down the aging process and improving the material's anti-aging performance. However, these small-molecule additives contain polar groups such as ester groups, amino groups, and phenolic hydroxyl groups, which have poor compatibility with non-polar polypropylene. This can easily lead to additive aggregation and migration, making it difficult to ensure uniform dispersion of the additives in the polypropylene matrix during processing and use. This not only reduces the material's anti-aging performance but may also harm the environment in which it is used.

[0004] In view of this, we propose an anti-ultraviolet heat-insulating polypropylene material and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-ultraviolet heat-insulating polypropylene material and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an anti-ultraviolet heat-insulating polypropylene material, comprising the following components: 65-85 parts polypropylene resin, 5-20 parts compatibilizer, 3-30 parts filler, and 0-5.0 parts additives.

[0007] More preferably, the polypropylene resin includes one or both of homopolymer polypropylene and copolymer polypropylene. Homopolymer polypropylene has a lower melt index, making it suitable for injection molding / blow molding; copolymer polypropylene has high impact resistance, meeting the performance requirements of packaging bottles.

[0008] More preferably, the filler is one or a mixture of hollow glass beads, mica powder, aluminum silicate fiber, aerogel, hydrotalcite, titanium dioxide, zinc oxide, indium tin oxide (ITO), antimony tin oxide (ATO), and tungsten bronze compound (MxWO3).

[0009] In the above technical solutions, hollow glass beads (glass microspheres) block heat conduction through their hollow structure, reducing the effective thermal conductivity and significantly reducing density, thus possessing lightweight and heat insulation properties. Mica sheets, with their layered structure, can extend the heat conduction path and reflect some infrared radiation, but the effect is poor, requiring a high filling volume. Alumina silicate fiber networks can block heat convection and conduction, improving the material's high-temperature resistance, but the heat insulation effect is limited. Aerogels (such as SiO2) with their nanoporous structure can suppress gas conduction and radiative heat transfer, exhibiting ultra-low thermal conductivity and excellent heat insulation. Hydrotalcite (LDH) absorbs heat through the decomposition of interlayer water molecules, and its layered structure blocks heat diffusion, providing good medium- and high-temperature heat insulation performance, while also possessing flame-retardant properties. Titanium dioxide has a high refractive index, reflecting some infrared light, but its own thermal conductivity is relatively high, resulting in poor heat insulation, although it has excellent ultraviolet shielding performance. Zinc oxide is similar to titanium dioxide, with a slightly lower thermal conductivity. ITO / ATO has the ability to reflect infrared radiation through free electrons, while tungsten bronze (M... x WO3 exhibits selective absorption / reflection of NIR due to plasma resonance effect, resulting in excellent thermal insulation performance.

[0010] Based on the above-mentioned filler properties, the filler is selected as a composite of hollow glass beads with low thermal conductivity and mica powder with sheet barrier capability, with a mass ratio of (2-3):1.

[0011] More preferably, the additives include, but are not limited to, one or more of the following: ultraviolet absorbers, light stabilizers, antioxidants, nucleating agents, lubricants, antistatic agents, and heat stabilizers.

[0012] In the above technical solutions, antioxidants effectively prevent the degradation of polypropylene resin during high-temperature processing and extrusion. Ultraviolet absorbers and light stabilizers inhibit the long-term aging of polypropylene resin; their combined use produces a synergistic effect, significantly improving the light weather resistance of polypropylene resin. Lubricants reduce friction between the polypropylene resin melt and the screw / die during processing, preventing melt fracture. Nucleating agents increase the crystallinity of polypropylene resin and enhance its rigidity, thereby ensuring that the produced products possess excellent and durable quality.

[0013] More preferably, the compatibilizer is maleic anhydride-grafted polypropylene (PP-g-MAH).

[0014] In the above technical solution, maleic anhydride-grafted polypropylene (PP-g-MAH) has polar anhydride groups, which can effectively improve the dispersibility of fillers in polypropylene resin and reduce agglomeration. In addition, PP-g-MAH can also enhance the compatibility between antioxidants, light stabilizers and other additives and polypropylene resin, and reduce the migration of additives.

[0015] A method for preparing an anti-ultraviolet heat-insulating polypropylene material includes the following process steps: mixing polypropylene resin, compatibilizer, filler and additives, extruding and granulating to obtain the polypropylene material.

[0016] More preferably, the filler is dried at 80±5℃ for 4 to 6 hours before mixing to remove moisture and prevent agglomeration.

[0017] More preferably, the mixing is carried out in a high-speed mixer at a speed of 500-800 rpm for a duration of 5-8 minutes.

[0018] More preferably, the extrusion granulation is carried out in a twin-screw extruder with a length-to-diameter ratio of 40:1, and the segmented temperatures are: 175-185℃, 195-205℃, 205-215℃, and 195-205℃ respectively.

[0019] More preferably, the filler undergoes surface modification, specifically as follows:

[0020] S1. Mix the filler, anhydrous zinc acetate, and ethanol aqueous solution, add titanium tetrachloride, and disperse evenly; add dopamine hydrochloride to adjust the pH of the system to 7.8-8.2, transfer to a reaction vessel, and react at 115-125℃ for 18-24 hours; centrifuge to remove the supernatant; wash with ethanol and water, centrifuge, and dry to obtain Zn-Ti composite filler;

[0021] S2. Disperse the Zn-Ti composite filler and the UV-resistant compound in anhydrous toluene and stir at 80-100℃ for 15-30 min; add catalyst A and react for 6-12 h; add 0.1M hydrochloric acid to terminate the reaction, precipitate in cold methanol, centrifuge, wash, and vacuum dry to obtain the modified filler.

[0022] More preferably, in S1, the Zn-Ti composite filler comprises the following components by mass: 10 parts filler, 3.7 to 5.5 parts anhydrous zinc acetate, 1.1 to 1.7 parts titanium tetrachloride, and 0.1 to 0.5 parts dopamine hydrochloride;

[0023] The ratio of filler to ethanol-water solution is (0.4–0.8) g / 100 mL;

[0024] In an aqueous ethanol solution, the volume ratio of ethanol to water is 1:1.

[0025] More preferably, in S2, the mass ratio of Zn-Ti composite filler to UV-resistant compound is 10:(1-3);

[0026] Catalyst A is stannous octoate, and its dosage is 1 to 5‰ of the total mass of the reaction system.

[0027] More preferably, the UV-resistant compound is one of methyl 2-(4-hydroxy-3-methylphenyl)acetate (CAS: 64360-47-0), 3,5-di-tert-butyl-4-hydroxyphenylacetic acid (CAS: 1611-03-6), methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS: 6386-38-5), and ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS: 36294-24-3).

[0028] In the above technical solution, the specific reaction mechanism of step S1 is as follows: Zinc acetate (Zn(OAc)2) provides zinc ions (Zn2+), which combine with hydroxyl groups (-OH) on the filler surface or the hydrolysis products of titanium tetrachloride (Ti-OH) to form coordination bonds or composite oxides (Zn-O-Ti). Titanium tetrachloride (TiCl4) hydrolyzes to generate Ti(OH)4 or TiO2 nanoparticles, which are co-deposited with Zn2+ on the filler surface to form a Zn-Ti composite layer. Dopamine hydrochloride (DA·HCl) undergoes oxidative self-polymerization under weakly alkaline conditions to form polydopamine (PDA), which coats the filler and enhances surface active sites (such as -NH2, -OH), providing anchoring sites for subsequent grafting. Ethanol aqueous solution is used to adjust solvent polarity, promoting the hydrolysis of TiCl4 and uniform coating of PDA.

[0029] In step S2, the UV-resistant compound undergoes transesterification, condensation, or esterification reactions with the -NH2 group of the PDA or the -OH group on the filler surface via ester / carboxyl groups, forming covalent grafts to load the UV-resistant organic structure onto the filler surface. Stannous octoate is selected as the catalyst to catalyze the reaction and promote the chemical bonding between the UV-resistant compound and the PDA / filler. Furthermore, nonpolar anhydrous toluene is added to the system to prevent moisture interference.

[0030] The modified filler prepared by the above method achieves chemical bonding of UV-resistant compounds through Zn-Ti co-deposition and PDA-mediated grafting reaction. The PDA and Zn-Ti coating on the surface of the modified filler improves its polarity, significantly enhancing its dispersibility in polypropylene resin, which helps to fully utilize the filler's properties. The modified filler can absorb UVB / UVA, and its hydroxyphenyl structure quenches free radicals, significantly improving its UV shielding ability. Furthermore, PDA and grafted chains enhance the interfacial adhesion between the filler and polypropylene, improving their interfacial bonding ability. Therefore, the modified filler possesses both UV shielding and interfacial compatibility.

[0031] After the modified filler prepared above is added to PP, (1) in terms of mechanical properties: the Zn-Ti / PDA layer can improve the interfacial bonding force between the filler and PP, reduce stress concentration, and improve its tensile strength and impact toughness, thus enhancing its mechanical properties. (2) in terms of UV aging resistance: the grafted 3,5-di-tert-butyl-4-hydroxyphenyl structure can capture and quench the free radicals generated by PP photo-oxidation, delaying yellowing and embrittlement; Zn-Ti oxides (such as TiO2) and UV-resistant compounds synergistically absorb ultraviolet rays, thereby improving the UV aging resistance of PP. (3) in terms of thermal stability: the PDA and Zn-Ti layers can delay the thermal degradation of PP, increase the thermal decomposition initiation temperature, and improve the thermal stability of the prepared polypropylene material. In summary, the polypropylene material with added modified filler has comprehensively improved UV aging resistance, mechanical strength and thermal stability, which can meet the UV protection requirements of packaging materials.

[0032] More preferably, the compatibilizer is functionalized polyethylene, specifically prepared by the following process:

[0033] (1) Mix EVA (ethylene-vinyl acetate copolymer) and xylene, heat to 120-140℃ and reflux to dissolve; add sodium hydroxide and react for 20-30 min; cool to room temperature and precipitate with anhydrous ethanol; wash the crude product with acid, water and ethanol, and dry it under vacuum at 50℃ to constant weight to obtain hydroxyl-functionalized polyethylene.

[0034] (2) Mix hydroxyl-functionalized polyethylene and UV-resistant compound at 60-80°C; add catalyst B and toluene, and heat to 100-160°C for 4-7 hours; evaporate under reduced pressure, wash and dry to obtain functionalized polyethylene.

[0035] More preferably, in step (1), the mass ratio of EVA to sodium hydroxide is 10:(0.18~0.22).

[0036] Sodium hydroxide was added in the form of a sodium hydroxide-ethanol mixed solution with a concentration of 0.1M;

[0037] The ratio of EVA to xylene is 10g / 100mL.

[0038] More preferably, in step (2), the mass ratio of hydroxyl-functionalized polyethylene to the UV-resistant compound is 100:(0.5-2.0).

[0039] Catalyst B is p-toluenesulfonic acid, and its dosage is 2.0% to 3.0% of the total mass of the reaction system.

[0040] The amount of toluene used is 5 to 10 times the mass of the hydroxyl-functionalized polyethylene; preferably, the ratio of toluene to hydroxyl-functionalized polyethylene is 10 g / 80 mL.

[0041] More preferably, in step (2), the reaction is carried out in a nitrogen atmosphere to prevent oxidation of phenolic hydroxyl groups; 0.1% BHT (butylated hydroxytoluene) is added to suppress free radical side reactions.

[0042] In the above technical solution, in step (1), the vinyl acetate (VAc) unit in EVA (ethylene-vinyl acetate copolymer) undergoes saponification under the catalysis of sodium hydroxide, hydrolyzing to generate hydroxyl groups (-OH), thus obtaining hydroxyl-functionalized polyethylene (EVA-OH). In step (2), the anti-UV compound reacts with the hydroxyl groups of EVA-OH through ester / carboxyl groups via transesterification, condensation, or esterification. By introducing hydroxyl groups through EVA saponification and then reacting them with the anti-UV compound, chemical grafting is achieved, resulting in a functionalized polyethylene product that possesses polarity, UV resistance, and thermal stability, significantly superior to unmodified EVA.

[0043] The functionalized polyethylene produced has a hydroxyl structure, which significantly improves its polarity; the grafted phenol structure absorbs UV and quenches free radicals, which significantly enhances its UV stability; the phenolic hydroxyl groups in its structure have antioxidant properties and can delay thermal degradation, thus improving its thermal stability; the enhanced polarity matching improves the interfacial adhesion and optimizes the compatibility, making it suitable as a compatibilizer to be added to polypropylene materials.

[0044] When functionalized polyethylene is added to PP as a compatibilizer, (1) in terms of interfacial compatibility: the polar groups of functionalized polyethylene form hydrogen bonds or chemical bonds with the modified filler, reducing phase separation and improving dispersibility. (2) in terms of mechanical properties: the interfacial bonding force is improved, and stress transmission is more effective; the compatibilizer can act as a toughening phase, absorbing impact energy, thus enhancing mechanical properties. (3) in terms of UV aging resistance: the grafted 3,5-di-tert-butyl-4-hydroxyphenyl structure directly captures the free radicals generated by PP photo-oxidation, and plays a synergistic protective role with the modified filler (containing Zn-Ti / PDA), jointly shielding UV and extending the outdoor service life of the material.

[0045] More preferably, the UV-resistant compound is prepared by the following process:

[0046] Under a nitrogen atmosphere, methyl gallate and diethylene glycol dimethyl ether were mixed, and 1,4-diacetylbenzene and sodium hydride were added. The mixture was refluxed at 80–85 °C for 6–8 h. Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added, and the reaction was continued for 8–10 h. The mixture was filtered and purified to obtain the diketone compound.

[0047] A diketone compound, potassium carbonate, and anhydrous tetrahydrofuran were mixed, and p-bromomethylbenzoic acid was added. The mixture was heated to 65–70 °C and refluxed for 6–8 h. The mixture was then evaporated under reduced pressure and recrystallized to obtain the UV-resistant compound.

[0048] More preferably, the molar ratio of methyl gallate, 1,4-diacetylphenyl, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and sodium hydride is 1:(1.0-1.1):(1.1-1.5):(2.1-2.5).

[0049] More preferably, the mass ratio of the diketone compound, p-bromomethylbenzoic acid, and potassium carbonate is 1:(1.0-1.1):(0.8-0.9).

[0050] The ratio of diketone compound to anhydrous tetrahydrofuran is 3.5 g / 100 mL.

[0051] In the above technical solution, the first step involves a stepwise reaction: under the action of sodium hydride, 1,4-diacetylbenzene reacts sequentially with methyl gallate and methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to form a molecule with a conjugated diketone (-CO-CH2-CO-) and tert-butylphenol structure, denoted as the diketone compound. The second step involves the reaction of bromomethylbenzoic acid with the phenolic hydroxyl site of the diketone compound. Potassium carbonate neutralizes the generated HBr, driving the reaction forward, ultimately generating a compound possessing the following functional groups: conjugated diketone, tert-butylphenol, and carboxybenzyl, denoted as the anti-UV compound, exhibiting UV absorption, free radical scavenging, and enhanced polarity and reactivity.

[0052] When used as an anti-UV compound to modify fillers, its carboxyl group (-COOH) forms hydrogen bonds or ester bonds with the -OH or -NH2 (PDA) on the filler surface, improving dispersibility; the diketone structure absorbs UVB, and tert-butylphenol quenches free radicals, exerting a synergistic effect of UV shielding, which is complementary to the Zn-Ti / PDA layer of the filler (which absorbs UVA).

[0053] When it is used as an anti-UV compound in the preparation of functionalized polyethylene, its carboxyl group (-COOH) condenses with the hydroxyl group of EVA-OH to form a more stable ester bond; covalent grafting can prevent the precipitation of small molecule anti-UV agents and extend durability.

[0054] When the functionalized polyethylene and modified fillers are applied to polypropylene materials, (1) the diketone and tert-butylphenol structures cover the UVB / UVA bands; together with the TiO2 (shielding the entire band) of the Zn-Ti filler and the phenolic hydroxyl group inhibiting the PP photo-oxidation chain reaction, they jointly improve the material's resistance to ultraviolet aging. (2) The anti-ultraviolet compounds form chemical bonds with the fillers and compatibilizers, reducing phase separation and improving tensile / impact strength, thus enhancing the mechanical properties of the polypropylene material. (3) The conjugated diketone and phenolic structures delay the onset temperature of PP thermal degradation, thereby improving the thermal stability of the polypropylene material. (4) The chemically bonded anti-ultraviolet agents prevent volatilization / precipitation during processing or use, and the tert-butyl group reduces the oxidative yellowing of the phenolic hydroxyl group, thus improving the processing and durability of the polypropylene material.

[0055] More preferably, the lubricant is zinc stearate.

[0056] The metal ions in the lubricant can form a stable six-membered ring chelate with the carbonyl oxygen atom (diketone) in the UV-resistant compound, which has strong absorption in the 280-400 nm range, further enhancing the UV absorption capacity of polypropylene materials; it can also inhibit free radical chain reactions and delay PP aging.

[0057] An application of an anti-ultraviolet heat-insulating polypropylene material involves injection blowing or extrusion blowing of the obtained polypropylene material, followed by post-processing to obtain a packaging container.

[0058] More preferably, the process conditions for injection blow molding are: injection section temperature 190~210℃, blow molding pressure 0.8~1.2MPa, and mold temperature 40~60℃.

[0059] More preferably, the extrusion temperature of the blow molding is 180-200°C, and the parison sag is controlled to avoid uneven wall thickness.

[0060] More preferably, the post-treatment process conditions are: placing in a 60°C oven for 2 hours to reduce internal stress.

[0061] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0062] 1. The present invention describes an anti-UV heat-insulating polypropylene material. Through Zn-Ti co-deposition and PDA-mediated grafting reaction, anti-UV compounds are chemically bonded to the filler surface, improving the filler polarity and significantly enhancing its dispersibility in polypropylene resin. This increases interfacial bonding strength, reduces stress concentration, and improves tensile strength and impact toughness, thereby enhancing mechanical properties. The modified filler can absorb UVB / UVA, and its hydroxyphenyl structure quenches free radicals, significantly improving the UV shielding properties of both the filler and the resulting polypropylene material.

[0063] 2. The UV-resistant and heat-insulating polypropylene material described in this invention introduces hydroxyl groups through EVA saponification, followed by reaction with UV-resistant compounds to achieve chemical grafting. This results in a functionalized polyethylene product that possesses polarity, UV resistance, and thermal stability. The polar groups of the functionalized polyethylene form hydrogen bonds or chemical bonds with the modified filler, reducing phase separation and improving dispersibility. The interfacial bonding force is enhanced, and stress transfer is more effective. The compatibilizer can act as a toughening phase, absorbing impact energy and thus enhancing mechanical properties. The grafted 3,5-di-tert-butyl-4-hydroxyphenyl structure directly captures free radicals generated by PP photo-oxidation, working synergistically with the modified filler to shield UV rays and extend the material's outdoor service life.

[0064] 3. The UV-resistant heat-insulating polypropylene material described in this invention is prepared by reacting 1,4-diacetylbenzene, methyl gallate, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and p-bromomethylbenzoic acid to generate a UV-resistant compound that combines conjugated diketones, tert-butylphenol, and carboxybenzyl groups. This compound has the characteristics of UV absorption, free radical capture, and improved polarity and reactivity, and can further improve the UV aging resistance, mechanical properties, thermal stability, processing, and durability of polypropylene materials. Detailed Implementation

[0065] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] In the following specific embodiments, all "parts" refer to parts by weight, unless otherwise specified;

[0067] The polypropylene resin is homopolymer polypropylene (Shanghai Petrochemical H2800) and copolymer polypropylene (Basel RP340R) in a mass ratio of 7:3;

[0068] The filler is a composite of hollow glass beads (3M iM16K) and mica powder (Anhui Gerui Mica-325) in a mass ratio of 3:1.

[0069] Maleic anhydride-grafted polypropylene: DuPont Fusabond M613;

[0070] The ultraviolet absorber is UV-531;

[0071] The light stabilizer is BASF Tinuvin 770;

[0072] The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1;

[0073] The lubricant is zinc stearate;

[0074] EVA: Yanshan Petrochemical Company, number average molecular weight (Mn) 15100 g / mol, vinyl acetate molar fraction 7 mol%

[0075] In an aqueous ethanol solution, the volume ratio of ethanol to water is 1:1.

[0076] Example 1: A method for preparing an anti-ultraviolet heat-insulating polypropylene material, comprising the following process steps:

[0077] Step 1: Under a nitrogen atmosphere, methyl gallate and diethylene glycol dimethyl ether were mixed, and 1,4-diacetylbenzene and sodium hydride were added. The mixture was refluxed at 80°C for 8 hours. Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added, and the reaction was continued for another 8 hours. The mixture was filtered and purified to obtain a diketone compound. The molar ratio of methyl gallate, 1,4-diacetylbenzene, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and sodium hydride was 1:1.0:1.1:2.1. The ratio of methyl gallate to diethylene glycol dimethyl ether was 3.5 g / 100 mL.

[0078] A diketone compound, potassium carbonate, and anhydrous tetrahydrofuran were mixed, and p-bromomethylbenzoic acid was added. The mixture was heated to 65°C and refluxed for 8 hours. The mixture was then evaporated under reduced pressure and recrystallized to obtain the UV-resistant compound. The mass ratio of the diketone compound, p-bromomethylbenzoic acid, and potassium carbonate was 1:1.0:0.8, and the ratio of the diketone compound to anhydrous tetrahydrofuran was 3.5 g / 100 mL.

[0079] Step 2, 2.1. Mix the packing material, anhydrous zinc acetate, and ethanol-water solution, add titanium tetrachloride, and disperse evenly; add dopamine hydrochloride to adjust the pH of the system to 7.8, transfer to a reaction vessel, and react at 115℃ for 18 hours; centrifuge to remove the supernatant; wash with ethanol and water, centrifuge, and dry to obtain Zn-Ti composite packing material; the Zn-Ti composite packing material comprises the following mass components: 10 parts packing material, 3.7 parts anhydrous zinc acetate, 1.1 parts titanium tetrachloride, and 0.1 parts dopamine hydrochloride; the ratio of packing material to ethanol-water solution is 0.4 g / 100 mL;

[0080] The Zn-Ti composite filler and the UV-resistant compound were dispersed in anhydrous toluene and stirred at 80°C for 15 min. 1‰ stannous octoate catalyst was added, and the reaction was allowed to proceed for 6 h. The reaction was terminated by adding 0.1 M hydrochloric acid, and the mixture was precipitated in cold methanol, centrifuged, washed, and vacuum dried to obtain the modified filler. The mass ratio of Zn-Ti composite filler to the UV-resistant compound was 10:1.

[0081] 2.2. Mix EVA and xylene, heat to 120℃ and reflux to dissolve; add 0.1M sodium hydroxide-ethanol mixed solution, react for 20 min; cool to room temperature, precipitate with anhydrous ethanol, wash the crude product with acid, water, and ethanol, and dry under vacuum at 50℃ to constant weight to obtain hydroxyl-functionalized polyethylene; the mass ratio of EVA to sodium hydroxide is 10:0.18; the ratio of EVA to xylene is 10 g / 100 mL;

[0082] Hydroxyl-functionalized polyethylene and an anti-UV compound were mixed at 60°C under a nitrogen atmosphere; 2.0% toluenesulfonic acid and toluene were added as catalysts, and the mixture was heated to 100°C and reacted for 7 hours; the mixture was then evaporated under reduced pressure, washed, and dried to obtain functionalized polyethylene; the mass ratio of hydroxyl-functionalized polyethylene to the anti-UV compound was 100:0.5; and the ratio of toluene to hydroxyl-functionalized polyethylene was 10 g / 80 mL.

[0083] The compatibilizer is functionalized polyethylene and maleic anhydride-grafted polypropylene in a mass ratio of 1:4.

[0084] Step 3: Mix 75 parts polypropylene resin, 10 parts compatibilizer, 10 parts modified filler, and 0.1 parts lubricant in a high-speed mixer at a speed of 500 rpm for 8 minutes; then extrude and granulate the mixture in a twin-screw extruder with an aspect ratio of 40:1 and segment temperatures of 175℃, 195℃, 205℃, and 195℃ to obtain the polypropylene material.

[0085] Example 2: A method for preparing an anti-ultraviolet heat-insulating polypropylene material, comprising the following process steps:

[0086] Step 1: Under a nitrogen atmosphere, methyl gallate and diethylene glycol dimethyl ether were mixed, and 1,4-diacetylbenzene and sodium hydride were added. The mixture was refluxed at 82°C for 7 hours. Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added, and the reaction was continued for 9 hours. The mixture was filtered and purified to obtain a diketone compound. The molar ratio of methyl gallate, 1,4-diacetylbenzene, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and sodium hydride was 1:1.05:1.3:2.3. The ratio of methyl gallate to diethylene glycol dimethyl ether was 3.5 g / 100 mL.

[0087] A diketone compound, potassium carbonate, and anhydrous tetrahydrofuran were mixed, and p-bromomethylbenzoic acid was added. The mixture was heated to 68°C and refluxed for 7 hours. The mixture was then evaporated under reduced pressure and recrystallized to obtain the UV-resistant compound. The mass ratio of the diketone compound, p-bromomethylbenzoic acid, and potassium carbonate was 1:1.05:0.85, and the ratio of the diketone compound to anhydrous tetrahydrofuran was 3.5 g / 100 mL.

[0088] Step 2, 2.1. Mix the packing material, anhydrous zinc acetate, and ethanol aqueous solution, add titanium tetrachloride, and disperse evenly; add dopamine hydrochloride to adjust the pH of the system to 8.0, transfer to a reaction vessel, and react at 120℃ for 21 h; centrifuge to remove the supernatant; wash with ethanol and water, centrifuge, and dry to obtain Zn-Ti composite packing material; the Zn-Ti composite packing material comprises the following mass components: 10 parts packing material, 4.6 parts anhydrous zinc acetate, 1.4 parts titanium tetrachloride, and 0.3 parts dopamine hydrochloride; the ratio of packing material to ethanol aqueous solution is 0.6 g / 100 mL;

[0089] The Zn-Ti composite filler and the UV-resistant compound were dispersed in anhydrous toluene and stirred at 90°C for 18 min. 3‰ stannous octoate catalyst was added, and the reaction was allowed to proceed for 9 h. The reaction was terminated by adding 0.1 M hydrochloric acid, and the product was precipitated in cold methanol, centrifuged, washed, and vacuum dried to obtain the modified filler. The mass ratio of Zn-Ti composite filler to UV-resistant compound was 10:2.

[0090] 2.2. Mix EVA and xylene, heat to 130℃ and reflux to dissolve; add 0.1M sodium hydroxide-ethanol mixed solution, react for 25 min; cool to room temperature, precipitate with anhydrous ethanol, wash the crude product with acid, water, and ethanol, and dry under vacuum at 50℃ to constant weight to obtain hydroxyl-functionalized polyethylene; the mass ratio of EVA to sodium hydroxide is 10:0.2; the ratio of EVA to xylene is 10 g / 100 mL;

[0091] Hydroxyl-functionalized polyethylene and an anti-UV compound were mixed at 70°C under a nitrogen atmosphere; 2.50% toluenesulfonic acid and toluene were added as catalysts, and the mixture was heated to 120°C and reacted for 5.5 hours; the mixture was then evaporated under reduced pressure, washed, and dried to obtain functionalized polyethylene; the mass ratio of hydroxyl-functionalized polyethylene to the anti-UV compound was 100:1.2; and the ratio of toluene to hydroxyl-functionalized polyethylene was 10 g / 80 mL.

[0092] The compatibilizer is functionalized polyethylene and maleic anhydride-grafted polypropylene in a mass ratio of 1:1.

[0093] Step 3: Mix 75 parts polypropylene resin, 15 parts compatibilizer, 15 parts modified filler, and 0.3 parts lubricant in a high-speed mixer at 700 rpm for 6 minutes; then extrude and granulate the mixture in a twin-screw extruder with an aspect ratio of 40:1 and segment temperatures of 180℃, 200℃, 210℃, and 200℃ to obtain the polypropylene material.

[0094] Example 3: A method for preparing an anti-ultraviolet heat-insulating polypropylene material, comprising the following process steps:

[0095] Step 1: Under a nitrogen atmosphere, methyl gallate and diethylene glycol dimethyl ether were mixed, and 1,4-diacetylbenzene and sodium hydride were added. The mixture was refluxed at 85°C for 6 hours. Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added, and the reaction was continued for 10 hours. The mixture was filtered and purified to obtain a diketone compound. The molar ratio of methyl gallate, 1,4-diacetylbenzene, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and sodium hydride was 1:1.1:1.5:2.5. The ratio of methyl gallate to diethylene glycol dimethyl ether was 3.5 g / 100 mL.

[0096] A diketone compound, potassium carbonate, and anhydrous tetrahydrofuran were mixed, and p-bromomethylbenzoic acid was added. The mixture was heated to 70°C and refluxed for 6 hours. The mixture was then evaporated under reduced pressure and recrystallized to obtain the UV-resistant compound. The mass ratio of the diketone compound, p-bromomethylbenzoic acid, and potassium carbonate was 1:1.1:0.9, and the ratio of the diketone compound to anhydrous tetrahydrofuran was 3.5 g / 100 mL.

[0097] Step 2, 2.1. Mix the packing material, anhydrous zinc acetate, and ethanol aqueous solution, add titanium tetrachloride, and disperse evenly; add dopamine hydrochloride to adjust the pH of the system to 8.2, transfer to a reaction vessel, and react at 125℃ for 24 hours; centrifuge to remove the supernatant; wash with ethanol and water, centrifuge, and dry to obtain Zn-Ti composite packing material; the Zn-Ti composite packing material comprises the following mass components: 10 parts packing material, 5.5 parts anhydrous zinc acetate, 1.7 parts titanium tetrachloride, and 0.5 parts dopamine hydrochloride; the ratio of packing material to ethanol aqueous solution is 0.8 g / 100 mL;

[0098] The Zn-Ti composite filler and the UV-resistant compound were dispersed in anhydrous toluene and stirred at 100℃ for 30 min. 5‰ stannous octoate catalyst was added, and the reaction was allowed to proceed for 12 h. The reaction was terminated by adding 0.1 M hydrochloric acid, and the product was precipitated in cold methanol, centrifuged, washed, and vacuum dried to obtain the modified filler. The mass ratio of Zn-Ti composite filler to UV-resistant compound was 10:3.

[0099] 2.2. Mix EVA and xylene, heat to 140℃ and reflux to dissolve; add 0.1M sodium hydroxide-ethanol mixed solution, react for 30 min; cool to room temperature, precipitate with anhydrous ethanol, wash the crude product with acid, water, and ethanol, and dry under vacuum at 50℃ to constant weight to obtain hydroxyl-functionalized polyethylene; the mass ratio of EVA to sodium hydroxide is 10:0.22; the ratio of EVA to xylene is 10 g / 100 mL;

[0100] Hydroxyl-functionalized polyethylene and an anti-UV compound were mixed at 80°C under a nitrogen atmosphere; 3.0% toluenesulfonic acid and toluene were added as catalysts, and the mixture was heated to 140°C and reacted for 4 hours; the mixture was then evaporated under reduced pressure, washed, and dried to obtain functionalized polyethylene; the mass ratio of hydroxyl-functionalized polyethylene to the anti-UV compound was 100:2.0; and the ratio of toluene to hydroxyl-functionalized polyethylene was 10 g / 80 mL.

[0101] Step 3: Mix 75 parts polypropylene resin, 20 parts compatibilizer functionalized polyethylene, 20 parts modified filler, and 0.5 parts lubricant in a high-speed mixer at 800 rpm for 5 minutes; then extrude and granulate the mixture in a twin-screw extruder with an aspect ratio of 40:1 and segment temperatures of 185℃, 205℃, 215℃, and 205℃ to obtain the polypropylene material.

[0102] Example 4: A method for preparing an anti-ultraviolet heat-insulating polypropylene material, comprising the following process steps:

[0103] Step 1: The UV-resistant compound is 3,5-di-tert-butyl-4-hydroxyphenylacetic acid; Steps 2-3 are the same as in Example 1, and polypropylene material is obtained.

[0104] Comparative Example 1: A method for preparing an UV-resistant heat-insulating polypropylene material, comprising the following process steps:

[0105] The compatibilizer is maleic anhydride-grafted polypropylene, and the other steps are the same as in Example 4 to obtain polypropylene material; the polypropylene material includes 75 parts polypropylene resin, 10 parts compatibilizer, 10 parts modified filler, and 0.1 parts lubricant.

[0106] Comparative Example 2: A method for preparing an UV-resistant heat-insulating polypropylene material, comprising the following process steps:

[0107] The compatibilizer is maleic anhydride-grafted polypropylene, and the filler is dried at 80℃ for 5 hours.

[0108] The other steps are the same as step 3 in Example 4, to obtain polypropylene material; the polypropylene material includes 75 parts polypropylene resin, 10 parts compatibilizer, 10 parts filler, 0.2 parts antioxidant, 0.3 parts ultraviolet absorber, and 0.2 parts light stabilizer.

[0109] Experiment: Polypropylene materials obtained in Examples 1-4 and Comparative Examples 1-2 were used to prepare samples. Their properties were tested and the test results were recorded.

[0110] Mechanical property testing: The tensile properties of the specimens were tested with reference to GB / T 1040.2, with a tensile rate of 50 mm / min and the specimens being dumbbell-shaped; The impact properties of the specimens were tested with reference to GB / T 1043, with the specimens being unnotched specimens and the specimen dimensions being 80 mm × 10 mm × 4 mm.

[0111] UV aging resistance test: Based on GB / T 16422.3 as the reference standard, the light source exposure test method was adopted. The sample was placed in a xenon lamp aging chamber (wavelength 290-800 nm, irradiance 0.5 W / m²@340 nm, black panel temperature 60℃, relative humidity 50%) and aged for 1000 hours. The tensile strength retention rate was then tested (comparing the data before and after aging).

[0112] Thermal insulation performance test: The thermal conductivity of the sample was tested using a thermal conductivity meter with GB / T 10295 as the reference standard.

[0113]

[0114] Based on the data in the table above, the following conclusions can be clearly drawn:

[0115] The polypropylene materials obtained in Examples 1-4 are compared with those obtained in Comparative Examples 1-2. The test results show that...

[0116] Compared to the comparative example and Example 4, the polypropylene materials obtained in Examples 1-3 exhibit higher tensile strength, impact strength, and tensile strength retention, as well as lower thermal conductivity. This clearly demonstrates that the present invention improves the mechanical properties, UV aging resistance, and thermal insulation properties of the prepared polypropylene materials.

[0117] Compared to Example 1, the UV-resistant compound in Example 4 was 3,5-di-tert-butyl-4-hydroxyphenylacetic acid; the compatibilizer in Comparative Example 1 was maleic anhydride-grafted polypropylene; and the polypropylene materials in Comparative Example 2 were all conventional components. The polypropylene materials obtained in Comparative Examples 1-2 and Example 4 showed decreased tensile strength, impact strength, and tensile strength retention, while their thermal conductivity increased. This indicates that the design of the polypropylene material composition and preparation process in this invention can promote a comprehensive improvement in its mechanical properties, UV resistance, and thermal insulation performance.

[0118] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A UV-resistant heat-insulating polypropylene material, characterized in that: It includes the following components: 65-85 parts polypropylene resin, 5-20 parts compatibilizer, 3-30 parts filler, and 0-5.0 parts additives; The filler undergoes surface modification, and the specific process is as follows: S1. Mix the filler, anhydrous zinc acetate, and ethanol aqueous solution, add titanium tetrachloride, and disperse evenly; add dopamine hydrochloride, adjust the pH of the system to 7.8-8.2, transfer to a reaction vessel, and react at 115-125℃ for 18-24h to obtain Zn-Ti composite filler; S2. Disperse the Zn-Ti composite filler and the UV-resistant compound in anhydrous toluene and stir at 80-100℃ for 15-30 min; add catalyst A and react for 6-12 h to obtain the modified filler; The compatibilizer is functionalized polyethylene, specifically prepared by the following process: (1) Mix EVA and xylene, heat to 120-140℃ and reflux to dissolve; add sodium hydroxide and react for 20-30 min to obtain hydroxyl-functionalized polyethylene; (2) Mix hydroxyl-functionalized polyethylene and UV-resistant compound at 60-80°C; add catalyst B and toluene, and heat to 100-160°C for 4-7 hours to obtain functionalized polyethylene; The UV-resistant compound is one of methyl 2-(4-hydroxy-3-methylphenyl)acetate, 3,5-di-tert-butyl-4-hydroxyphenylacetic acid, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or is prepared by the following process: Under a nitrogen atmosphere, methyl gallate and diethylene glycol dimethyl ether were mixed, and 1,4-diacetylbenzene and sodium hydride were added. The mixture was refluxed at 80-85°C for 6-8 hours. Methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added, and the reaction was continued for 8-10 hours to obtain a diketone compound. A diketone compound, potassium carbonate, and anhydrous tetrahydrofuran were mixed, and p-bromomethylbenzoic acid was added. The mixture was heated to 65-70°C and refluxed for 6-8 hours to obtain an anti-UV compound. The filler is a composite of hollow glass beads and mica powder, with a mass ratio of (2-3):

1.

2. The UV-resistant heat-insulating polypropylene material according to claim 1, characterized in that: The preparation method includes the following process steps: mixing polypropylene resin, compatibilizer, filler and additives, extruding and granulating to obtain polypropylene material.

3. The UV-resistant heat-insulating polypropylene material according to claim 1, characterized in that: In S1, the Zn-Ti composite packing comprises the following components by mass: 10 parts packing, 3.7–5.5 parts anhydrous zinc acetate, 1.1–1.7 parts titanium tetrachloride, and 0.1–0.5 parts dopamine hydrochloride; In S2, the mass ratio of Zn-Ti composite filler to UV-resistant compound is 10:(1-3).

4. The UV-resistant heat-insulating polypropylene material according to claim 1, characterized in that: The mass ratio of hydroxyl-functionalized polyethylene to UV-resistant compound is 100:(0.5-2.0).

5. The UV-resistant heat-insulating polypropylene material according to claim 1, characterized in that: The molar ratio of methyl gallate, 1,4-diacetylbenzene, methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and sodium hydride is 1:(1.0-1.1):(1.1-1.5):(2.1-2.5); the mass ratio of diketone compound, p-bromomethylbenzoic acid, and potassium carbonate is 1:(1.0-1.1):(0.8-0.9).

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